MCB: Kurssammanfattning Flashcards

Question

Cancer genetics according to Theodor Boveri

Answer 1

Boveri gave the chromosomal theory of heredity. Showed that fertilization of sea-urchin eggs by two sperm eggs gave multiple cell poles that cause unequal segregation of chromosomes - Specific chromosomes gave rise to particular phenotypes - Genetic imbalance can result in death - Individual chromosomes must carry different information Predicted the cell cycle and much of the biology of cancers.

Answer 2

Subsitution of one DNA base pair to another Missense : substitution of one aa Nonsense: base substitution --> premature stop codon Splicing effect: Base substitution near intron-exon junctions.

Answer 3

Hybrid chromosome result of joining one part of chromosome to another. Gives - Structurally changed gene version and its protein - Gene under new trancriptional contorl

Answer 4

Often give increase levels of mRNA and protein expression Amplified genes may form two types of microscoplcally abnormal chr. config.: DM : Double minutes, small paired extrachromosomal chromatin bodies segregating randomly during mitosis HSR: Homogenously staining regions, expanded chromosomal regions that do not exhibit normal banding patterns

Answer 5

Single base - complete chromosomes Large deletions inactivate all the genes included within it In frame deletion: Consequence depend on funciton of deleted segment Out of frame deletion: Consequence is frameshift - premature stop codon

Answer 6

Single base to kbps Less common as mutation events in cancer genes In frame insertions Out of frame insertion - consequence is frame shift - premature stop codon

Answer 7

Occurring but does not give an advantage to the cells. Genetic changes that do not confer any selective advantage in cancer developement.

Answer 8

Can make a difference, giving more proliferation. Genetic changes that give selective advantages to clones during cancer developement.

Answer 9

mutation in one of the enzymes present used to repair the cells Accumulation speeds up.

Answer 10

Mutations that are acquired as opposed to inherited

Answer 11

Pattern of mutations produced by a mutational process

Answer 12

Total genetic changes observed in the cancer genome: sum of all mutational signatures occurring in a lifetime

Answer 13

Variation in length of homopolymeric regions (particularly poly(A) sequences) – Variation in the length of dinucleotide and trinucleotide repeat regions – Associated with defective Mismatch Repair (MMR)

Answer 14

– Abnormal variation in gross chromosome number (aneuploidy) * Loss of chromosomes can be balanced (duplication of the remaining WT chromosome) or result in loss of heterozygosity (LOH) – Increased rate of chromosomal alterations * 10-100 fold increased rate of chromosome gain or loss and similar rates for LOH at specific genomic sites. – The molecular origin of CIN is less well established * Abnormal centrosome function in cancer cells can cause chromosome instability – Centrosome overduplication resulting in multifocal spindles and grossly abnormal mitoses * Improper behavior of the mitotic spindle can be due to defects in mitotic checkpoints

Answer 15

In the metaphase, microtubules will attach to the chromosome. Many proteins are involved in the fine tuning of this process. In the prometaphase the chromosomes ae not yet aligned correctly and you cannot start pulling apart the chromatids yet. CDC20 and APC/C complex will drive the process of chromosomal segregation. If bound to MAD2 it is inactive.

Answer 16

Premature anaphase entry. 50% of MAD2 removed in order to induce. Gives chromosome loss

Answer 17

Separain-securin forms a complex to help cleave aligned the cohesins correctly during the metaphase. If not working then incorrect cutting of chromosome

Answer 18

chromosome shattering. Cancer genomes usually have strange things such as reshuffled genomes in cancer. Chromosomal breakage leads to non-homologus end joining wich lead to the loss of the cell.

Answer 19

Cancerous syndrome in human. Very large protein, that is very different from the Anaphase Promoting Complex. Large protein with different domains. Some parts b-cathein degradation proteins. Microtubule binding domain binding to kinetochore of chromosomes. - tumor suppressor gene, keeps genes away from being expressed unless it has a signal that signifies it. - APC mutant cells have no connection to microtubules - Gene for colon cancer - Germline mutation cause FAP - Very important for Wnt signalling pathway

Answer 20

The pathway is simple. APC is part of a complex with B-catenin and axin/conduction. Allows phosphorylated B-catenin to be ubiquitylated. Cytoplasmic B-cathein will be degraded in the absence of Wnt signal

Answer 21

* Oxidative agents side effect of its own mitochondrial energy metabolism. Reactive oxygen species (ROS) attack DNA. Much more oxidation of DNA when you have a higher metabolic rate * Spontaneous disintegration of DNA Hydrolysis of nucleotides - abasic sites Deamination of cytosine, adenine, guanine and 5-methylcytosine converts these bases to miscoding Uracil, Hypoxanthine, Xanthine and Thymine * Radiation UV, Gamma and X-ray * Food constitutents Aromatic amines - causes DNA damage and is highly mutagenic * Chemical agents Mustard gas, genotoxic compounds present in cigarette smoke *Physical carcinogens Asbestos - leads to inflammatory condition that will cause colleteral damage *Aflatoxin Important to store food safely to reduce risk *Inflammation can be mutagenic -Caused by for example hepatitus B and C, HPV -Chronic inflammation in lungs of smokers

Answer 22

Test to estimate if a product is carcinogenic or not. Take for instance rat liver cells and homogenize them. Then add test compound that you assume could be cancerous. Then you add this to Salmonella which cannot grow on a medium without histidine. If the product is mutagenic, a mutation will happen leading to histidin being produced; hence Salmonella will grow. Still used today.

Answer 23

- DNA alkyltransferases: Single repair proteins that directly revert certain injuries The easiest and most perfect DNA repair mechanism is mediated by O6-alkylguanine-DNA alkyltransferase - Nucleotide excision-repair (NER): Deals with whole class of helix distorting lesions which generally obstruct transcription, Lesions of exogenous origin, Most versatile in lesion recognition, Only one DNA strand is affected - Base excision-repair (BER): Small chemical alterations of bases are targeted by BER, Lesions of endogenous origin, Only one DNA strand is affected, Mutations arisen due to metabolic action. - Mismatch Repair (MMR): Repairs base mismatches, single base loops, insertion and deletion loops (mainly replication errors) , Used to solve replication errors. DNA polymerase has issues with repeated codons. - Homologous recombination, Double strand breaks (DSB) - both strands are affected (most difficult to repair. Seems to dominate during S and G2 (DNA is already replicated). HDR or NHEJ - End joining; DSB repair, Most active in G1 (no second copy available) – much less accurate

Answer 24

Disease inherited strictly autosomal recessive. Median age of skin cancer onset is 8 years. The incidence of basal cell carcinoma is 1000 fold to unaffected individuals. A mutation in XP that makes you unable to handle UV damage. The repair system is not working.

Answer 25

A variant of XP that is clinically indistinguishable from the normal XP. The XPV gene is the DNA polymerase η that has a error rate 6000x that of high fidelity DNA pol and can bypass DNA lesions and incorporates nucleotides opposite of DNA damage

Answer 26

Homology directed repair (HDR) A crucial role during the normal cell-devision cycle (repairing strand breaks arising during DNA replication). Have for certain neurogenesis defects been seen in DSB repair mutants.

Answer 27

Nonhomologous end-joining (NHEJ) Error-prone repair process. Responsible for the rejoining of DSB during V(D)J recombination.

Answer 28

Identify coding regions, mix WT and mutated DNA and denaturate. When DNA is kept ss you can see the base complimentary interaction. Radioactivity is used to detect mutations because sporadic mutations will not be identified by Sanger since only a part of the fragments will be mutated. Mutation has to be present in more than 50% of the cells to be detected by Sanger. With radioactivity you have an enormous sensitivity.

Answer 29

If you would run the heteroduplexes on a gel you would see mobility shifts. +of the triethylammonium ion interacts electrostatistically with -charge of DNA. Determines precisely amount dsDNA present. For heteroduplexes, they don’t binds as strong to the column and will come out much earlier. The WAVE system is a fully automated dHPLC system that uses UV and/or fluorescence to detect DNA. SYBR green for example is very sensitive. It is a computer controlled automated data acquisition. The technique is very precise is detecting mutations.

Answer 30

qPCR, can use intercalating dyes to detect DNA, such as SYBR green. One big disadvantage with SYBRgreen is if you add too much then it will be toxic to TAG polymerase. ?Heteroduplexes melt easier than homoduplexes, but if you have too little SYBR green you wont be able to detect it.

Answer 31

- RNA virus oncogene - Cellular proto-oncogene - DNA virus oncogene - Cellular tumor suppressor gene

Answer 32

- Signalling molecule - Signal receptor - Intracellular transducers - Apoptotic proteins - DNA repair proteins - Cell cycle control proteins - Transcription factors

Answer 33

v-erbB is the EGF receptor with extracellular domain missing The EGF receptor is heavily amplified in many cancers. Just a single mutation from Val to Glu make the ligand receptor Her2 independent and it starts acting as a oncopotein.

Answer 34

- Transfect mouse with DNA from human tumor cells - Culture for 2 weeks - Focus of transformed NIH/3T3 cell growing among untransformed cells - Extract DNA, transform new mouse cells - Second cycle - Extract genomic DNA - Introduce into phage vector - Plate phage on E.coli - Put replica on filter paper using alu probe - Oncogene

Answer 35

Viral infections are linked to at least 15% of all malignant tumors in humans - the second most common identified risk factor for human cancer after tobacco smoking. Both RNA and DNA viruses are linked to various forms of human malignancies. Retroviruses are rare cancer causes in humans. Oncogenic DNA viruses are important causative agent in human cancer The amount of virus-associated cancers may further increase with the improvement of viral detection techniques.

Answer 36

There is a belt in Africa and some parts of South East Asia of Burkitts-lymphoma (BL). It seems to be an quite clear overlap between the spread of malaria and BL First human tumor associated with virus B-cell lymphoma Most common tumor form in African children

Answer 37

3 subtypes; Endemic: Associated with malaria and EBV infection 100% Spoaridc: Predominantely North America and EU, rarely EBV infetion Immunodeficiency-associated: Most seen in HIV patients and <50% associated with EBV

Answer 38

Most people will be infected by EBV virus at some part of their life. It seems like in certain regions of the world EBV causes cancer. As long as you have a stable immune system you can counter the infection. EBV gene products have tropism for B-cells During an infection the B-cells are activated. If going on for a long time, like if you have HIV infection, the B-cells are chronically activated and we see a constant rearrangement where the risk that something goes wrong increase. The EBV virus might be able to infect the B-cells and with the use of Pf, that is prevalent in areas with malaria, the release of virus from the B-cells can be activated. --> increase of infected B cells which will increase peripheral viral load and decrease T-cell immunity.

Answer 39

EBNA-1: constantly expresssed in BL EBNA-2: transactivator of cellular functions key protein in immortalization of B cells in culture EBNA3A and 3B: growth stimulation of B cells LMP1: is able to induce tumorigenic transformation of rodent fibroblasts it inhibits cell differentiation and alters cytokeratin expression

Answer 40

In Burkitt’s lymphoma the expression of c-myc is placed under control of the transcription-controlling sequences of an immunoglobin gene * Chr 14 – heavy-chain immunoglobin gene – 75 % of translocations in BL * Chr 22 – l antibody light-chain gene – 16 % of translocations in BL * Chr 2 – k antibody light-chain gene – 9 % of translocations in BL

Answer 41

-African BL -B-cell lymphomas of immunosuppressed patients - HIV patients -Some cases of Hodgkins lymphoma -Nasopharyngeal carcinomas (NPC) - South east asia.

Answer 42

Over 2 billion peopel. 40% lifetime risk of HCC, a type of liver cancer

Answer 43

HPV exists in about 120 different strains Only vaccination against most common ones. Most common strains in human tumors are HPV-16 and -18, account for 70% of cervical cancer cases

Answer 44

30-60% of sexually active men and women infected with genital HPV, mostly asymptomatically

Answer 45

a) Infection of basal/suprabasal keratinocytes b) Non-cytosolic virus replication, expression of early crf genes; gives distal movement of infected cells, 'late' gene expression and capsid formation and viral DNA linearization d) Viral DNA linearization - Viral DNA integration into host cell genome - unprotected viral oncoprotein production and host cell transformation e) Invasive neoplasia

Answer 46

6 Early proteins E1-2, E4-7 * Limited viral replication accompanied by E1 and E2 expression in undifferentiated keratinocytes in basal layers of stratified epithelium * E6 and E7 expressed in more distal layers * If breaks happen in E2, E2 mediated transcriptional repression of E6 and E7 will be lifted -> dysplasia * 3 proteins essential for transformation to HIV in humans (E5), E6, E7 * E6 triggers destruction of p53 * E7 degrades pRb that is a tumor suppressor protein 2 late proteins, L1-2

Answer 47

- Somatic cell fusion; HELA X normal fibroblasts gave reversion of tumorigenicity - Microcell fusion; transfer of single tagged normal chromosomes able to suppress tumorigenicity in specific cell lines - Familial cancer; Gene that conferred inherited tumor susceptibly behave mendelian dominant

Answer 48

Tumorigenicity is the tendency for cultured cells to give rise to either benign or malignant growing tumors when infected to in immunologically nonresponsive animals.

Answer 49

A rare childhood tumor. Abnormal proliferation of the retina. Quite common that the children have bilateral cancer - Most common at a very young age. Points towards something in the germline of those children. With children of bilateral retinoblastoma the incidence of other cancers over time is very common.

Answer 50

Clonal evolution. If you have a situaition with majority of S4 cells, it is still important to know about S1, S2 and M2 (other populations present) If we remove S4, other populations will take the lead. We want to wipe out all populations.

Answer 51

It has been thought that when cells get their differentiation it is the end of their story, it will not change. But now it has been seen that normal cells have some sort of plasticity. - Niche cells - Stem cells: Give rise to progeny, very controlled programme. Has a very important function in replenishing (påfyllning) the organ.

Answer 52

One idea with tumor cells is that the founder mutation needs to be in a normal stem cells like APC, because then the progenitors are massively more proliferated and more mutations will occur.

Answer 53

- Two hits needed to induce tumor formation from normal tumor suppressor gene - WIth tumor suppressor gene that has a germline mutation in one allele - only 1 hit needed to induce mutation. The first hit is inherited

Answer 54

Selected mutation so level of B-cat is higher than normal but not too high - if cell start to proliferate too fast cell will go into phase when unable to divide anymore

Answer 55

Loss of heterozygosity Long arm for breast cancer chromosome >50% of cases lost. Perhaps tumor suppressor genes present there. Look at SNPs but mostly length polymorphism to see if gene is LOH. PCR to amplify polymorphism

Answer 56

Ratio of alleles can be disturbed by variety of chromosomal mechanisms; chromosomal aneuploidy, local amplificiation, LOH ( At x Bn) / (Bt x An) <- A & B intensities of the 2 alleles; n- normal, t - tumor. AIF = infinite (LOH pure tumor population) AIF = >5 - LOH (Tumor cell population 80% pure) AIF = 2-5 - Can be explained by range of chromosomal mechanisms AIF = <2 - Trisomies and hard to distinguish AIF from experimental noise

Answer 57

- Disregard weak AIF and complex patterns of AI - LOH in defined histological subclasses should be excluded - Common regions of LOH should be confirmed in a series of tumors

Answer 58

TUMOR SUPPRESSOR: MiRNAs can function as tumor suppressors by inhibiting the expression of oncogenes, which are genes that promote the development of cancer. When miRNAs bind to complementary sequences in the mRNA of an oncogene, they can prevent the mRNA from being translated into protein. This can inhibit the proliferation of cancer cells and help to prevent the formation of tumors. ONCOGENE: miRNAs can also function as oncogenes by promoting the expression of genes that are involved in cancer development. For example, certain miRNAs may promote the proliferation of cancer cells or inhibit the apoptosis (programmed cell death) of cancer cells, leading to the formation of tumors.

Answer 59

Telomeres give a finite replicative life span of the chromosomes Once they become smaller than a threshold length, the senescence phenotype is provoked.

Answer 60

Prevent ends of linear chromosomes from appearing as DNA breaks, protect chromosome ends from degradation and fusion, allow complete chromosome replication and position chromosomes within the nucleus.

Answer 61

Replication of linear chromosomes - end replication problem as some RNA terminal primer will not be replace with DNA. Always a loss of DNA during replication of the lagging strand.

Answer 62

cell stops dividing and performing normal function

Answer 63

If cells are able to bypass senescence, eventually they will reach second proliferative block, often referred to as “CRISIS” when the absolute critical length of telomeres are reached. This is characterized by genomic instability and massive cell death. 1 of 10^7 emerge from this cell population in crisis have the ability to maintain their telomeres at stable length and spawn clone of ‘immortalized’

Answer 64

Bypassing senescence can be induced by introduction of SV40 Large T- antigen or HPV E6 and E7 - functional inhibition of Rb and p53. Cells bypassing senescence will continue to divide with further shortening of their telomeres (20-30 additional doublings)

Answer 65

Telomeres are not the only determinants of senescence. 1. If they were, that would mean that activation of telomerase into any cells should result in the immortalization of those cells 2. Introduction of oncogenes such as H-ras and raf result in induction of a senescent phenotype indistinguishable from cells undergoing replicative senescence 3. Young human diploid fibroblasts become senescent when exposed to DNA damaging agents or oxidative stress 4. Rodent cells express telomerase and maintain very long telomeres yet undergo senescence in culture

Answer 66

- Cell proliferation (short telomeres) - DNA damage - Oncogenes - Strong mitogens/ stress All potential cancer causing events

Answer 67

SAF or senescence associated foci are structures formed within cells in response to cellular senescence. SAFs are composed of proteins. SAFs are thought to play a role in the regulation of senescence and may be involved in the development of age-related diseases.

Answer 68

Ribonucleoprotein. Telomerase is a reverse transcriptaste; making DNA from an RNA template. Telomerase holoenzyme adds the DNA repeats to ends of chromosomes in the process called telomere extension. The enzyme consists of TERT (telomerase reverse transcriptase) and TER (telomerase RNA). TERT uses TER as template to make the telomere repeats and add them to the end of chromosomes. The main function of telomerase is to maintain the length of telomeres.Telomerase helps to prevent telomere shortening by adding telomere repeats to the ends of chromosomes, thereby maintaining their length. Telomerase is active in most cancer cells, which helps them to evade cell senescence and replicate indefinitely. In normal, non-cancerous cells, telomerase is usually only active during development and in certain types of stem cells.

Answer 69

Alternative lengthening of telomeres (ALT) is a mechanism by which some cells can maintain telomere length and evade senescence in the absence of telomerase. In some cancer cells and some normal cells, such as certain human immortal cell lines and some mouse embryonic stem cells, telomerase is not active and yet these cells are able to maintain telomere length and evade senescence. This is because these cells use the ALT mechanism to maintain telomere length. The ALT mechanism involves the use of homologous recombination to exchange telomere repeats between chromosomes. This process results in the synthesis of new telomeres, which allows the cells to maintain telomere length and evade senescence. The ALT mechanism is thought to be responsible for maintaining telomere length in approximately 10-15% of human cancers

Answer 70

Group of proteins that helps to protect the telomeres. Consists of 6 proteins; TRF1, TRF2, TIN2, TPP1, POT1 and Rap1. Proteins work together to protect telomers and prevent them to be recognized as DNA damage. Helps maintain telomere structure. Regulate activity of telomerase

Answer 71

Trp53+ - Apoptosis - Cell Cycle Arrest - Senescence --> - Stem cell dysfunction --> - Degenerative pathologies --> Ageing Trp53- - End-to end fusions - Endoreduplication --> - Breakage-fusion-bridge cycles - Polyploidy or aneuploidy --> Cellular transformation --> Cancer metastasis

Answer 72

Part of Shelterin complex present on mammalian telomeres, binds to telomere repeats. Inhibition with dominant negative allele lead to deprotection of telomerase. Cellular consequences; apoptosis or sensecnece. Inhibition gives breakage of chomosomes at new positions

Answer 73

Mitosis not done as it should due to unprotected chromatid ends because of loss of telomere cap --> leading to ends fusing together and these give rise to breakage that is new --> followed by enabling fusion with non homologus chromosomes.

Answer 74

* Ulcerative colitis (UC) - Chronic inflammation contributes to cancer via telomere collapse - Non progressors - no cancer - Progessors: multiple intestinal cancers * Dyskeratosis Congenita (DC) - Defective telomerase function explains rare familial syndrome. - DC humans have defects in highly regenerative tissues like skin and bone marrow + reduced chromosomal stability. - X linked form of disease; mutation in Dyskerin (associates with hTR) - Autosomal dominant forms caused by inheritance of mutant hTR and hTERT alleles * Also fuel growth for some tumors

Answer 75

a) Primary tumor b) Proliferation/ Angiogenesis c) Detachment /invasion - local invasion e) Embolism /circulation f) Transport - survives in the circulation g) Organ arrest h) Adherence to vessel wall i) Extravasation j) Metastasis

Answer 76

- Mesenchymal - Amoboid invasion - Collective cluster invasion - Collective strand invasion

Answer 77

- Large class of transmembrane molecules involved in direct cellular communication with the ECM. - Large family of heterodimeric complexes. - Major function to modulate attachment - which is implicated in growth, development, adhesion, migration and morphology.

Answer 78

Hallmark of epithelial differentiation. Loss of E-cad is one of the most wide abberrations in cell to environment interaction in human cancer Loss of E-cad not enough to induce EMT - Adhesion - Motility - Proliferation - Actin Cytoskeleton - Transcriptional/ Nuclear Role - Receptor Signalling

Answer 79

Epithelial Mesenchymal Transition (EMT) A natural occurring process. But is awakened very open in cancer cells with epithelial origin giving them a lot of plasticity. Epithelial-mesenchymal transition (EMT) is a process that involves the transformation of cells from an epithelial phenotype to a mesenchymal phenotype. During EMT, cells undergo a number of changes at the molecular and cellular level. These changes include the downregulation of epithelial markers, such as E-cadherin, and the upregulation of mesenchymal markers, such as vimentin. Cells also become more motile and invasive, and they may gain the ability to migrate and invade other tissues. EMT is a normal process that occurs during development, but it can also be induced in response to various stimuli, such as injury or inflammation. EMT is thought to play a role in a variety of physiological and pathological processes, including tissue repair, wound healing, and cancer progression.

Answer 80

- Epithelial cells form the lining of organs and tissues in the body and are characterized by their ability to form tight junctions with their neighbors and by their ability to adhere to the underlying extracellular matrix. - Mesenchymal cells, on the other hand, are more mobile and have a more fibroblast-like appearance. They are also more prone to migrate and are involved in tissue remodeling and repair.

Answer 81

Parallell progression - In models of pancreatic cancer. By lineage tracing these cells when they are benign already undergo EMT and cells start to migrate. Metastasis before we even have cancer. Possible recurrence - expression of mesenchymal markers after chemotherapy. These tumors are extremely aggressive, start to invade and migrate even more.

Answer 82

Name - Type transcription factor SNAI1 - C2H2 type zinc finger SNAI2 - C2H2 type zinc finger Twist - bHLH Goosecoid - Paired homeodomain FOXC2 - Winged helix/ forkhead ZEB1 - 2-handded zinc finger/ homeodomain ZEB2 - 2-handed zinc-finger / homeodomain E12/E47 - bHLH, still under disccusion if possible to induce EMT.

Answer 83

- Post-translational control - Transcriptional control - Differentiated splicing - Non-coding RNA regulation

Answer 84

Leads towards mesenchymal direction

Answer 85

Balances ZEB transcription factor function. Lowered in many cancer cells .Defects in the regulation of ZEB by miR200 have been implicated in several diseases, including cancer, where ZEB deregulation can contribute to the development of a more aggressive and invasive tumor. If inhibited, more mesenchymal state.

Answer 86

MET is an early event during preprogramming of mouse fibroblasts. Sox2, Klf5, Oct4 and Myc are the transcription factors used. Preventing MET impairs the iPSC generation. Klf4 induces e-cad expression, giving rise to MET. BMP signalling induces MET. Fibroblast reprogramming into iPSCs entails a MET.

Answer 87

K14 snail mice are a strain of genetically modified mice that express a protein called snail1 in their skin cells. Snail1 is a transcription factor that is involved in the process of epithelial-mesenchymal transition (EMT), which is a process that occurs during the development of an embryo. EMT is important for the proper formation of organs and tissues, but it can also be reactivated in adults, leading to the development of cancer or other diseases. Mice with Snail had higher rate of proliferation and an epithelium with more layers. Snail+ mice also had a much higher rate of tumors. Snail+ animals have much more stem cells and progenitors, which probably fuel much more tumors frequently popping up. CD34+ is upregulated with Snail+ animals. Leads to dysregulation of chromosomal regulation. Foxm1 turned on very strongly, usually not that much expressed. For snail+ animals we see issues with spindle formation.

Answer 88

Regulates skin tumor initiation, stemness and progression Very low expression is enough to increase p53 cell apoptosis.

Answer 89

Regulates skin tumor initiation, stemness and malignant progression Very low expression is enough to increase p53 cell apoptosis.

Answer 90

Preneoplastic dissemination refers to the spread of preneoplastic cells, which are cells that have undergone genetic or epigenetic changes that increase their risk of becoming cancerous, but have not yet developed into cancer.

Answer 91

Does not show abnormal proliferation but already in other sites

Answer 92

Circulating tumor cells. If EMT is detected here with breast and prostate cancer it is linked to unfavorable otcome.

Answer 93

* Lack of angiogenesis * Immune surveillance * Balanced proliferation and apoptosis * EMT state of DTCs

Answer 94

- Insoluble ECM, contains collagens, laminins, fibronectin, vitronectin, tenascin and proteoglycan - Stroma; consists out of fibroblasts, adipose, vasculature and resident immune cells - Conventional millieu of cytokines and growth factor

Answer 95

Cell death from loss of connection to ECM. TrKB is a suppressor of anoikis.

Answer 96

It has been believed that the circulation is a hostile environment for tumor cells and that the majority is killed in it, but has been seen that most cancer cells succesfully extravasate after 3 days of injection → 80% of cells survived. After extravasation only a small proportion (≈2% of original inoculum) of extravasated cells began to grow to form micrometastasis. Only 0.02% of original inoculum succeeded in forming macroscopic metastases. Large population of single cells (≈36% of inoculum) observed in liver tissue at 2 weeks after injection - intact but dormant

Answer 97

– Compounds that are structurally similar to naturally occuring substances such as vitamins, purins, pyrimidine bases, nucleosides and amino acids (e.g. 5-fluorouracil (pyrimidine analogue) – Antimetabolites interact with the cellular function in one of the following ways * Substituting for a metabolite that is normally incorporated into a key molecule such as DNA, RNA * Competing with a normal metabolite for occupation of a catalytic site of a key enzyme * Competing with a normal metabolite that acts at an important enzyme regulatory site or receptor – Most antimetabolites have their greatest activity during S phase

Answer 98

– Inhibiting DNA replication affords a logical approach for retarding tumor growth – Alkylating agents -highly reactive molecules that react via the alkyl group chemical group (R-CH2) – most used alkylating agents bind the major groove of DNA at the N7 position of guanine – Many antitumour agents currently in the cancer armamentarium have two alkyl groups that form crosslinks and are known as bifunctional * DNA alkylators (mono), DNA cross-linkers (bifunctional) – Cisplatin, carboplatin, and oxaliplatin inhibit DNA synthesis through the formation of intrastrand crosslinks in the DNA and formation of DNA adducts. These compounds are widly used in the treatment of malignancies

Answer 99

(also known as anti-mitotic agents or microtubule-active drugs) – Antimicrotubule agents are devided into two groups depending on whether they polymerize or depolymerize – Microtubules play important roles in the movement of intracellular vesicles and organelles such as the Golgi apparatus, chromosomes (prevent assembly of the mitotic spindle) and mitochondria

Answer 100

Anti-cancer drugs should act upon or in some way exploit the precise molecular abnormalities that drive malignant progression and should be more efficacious and selective against cancer cells than current agents which are largely cytotoxic in nature For the future cancer therapy will become more personal by sequencing methods enabling a more precise treatment.

Answer 101

- Focus on new molecular targets driving molecular pathology and progression of human cancers; Intellectual framework to discover new drugs with improved efficacy and selectivity. - Using of HTS, combinatorial chemistry and microarrays; accelerates drug discovery and development - Use of pharmacokinetic and pharmacodynamic endpoints; enhances rationality and hypothesis testing power of early clinical trials, basis for early go/no-go, reduce risk at late-stage failure - Developmenet of diagnostic, prognostic and pharmacogenomic biomarkers; enables targeting of individualized treatments to patients most likely to benefit

Answer 102

Not all need to be met to go on in drug discovery program. However, if several are met, it will give increased confidence and reduced risk for project - Frequency of genetic or epigenetic deregulation of the target/pathway in human cancer - Demonstration in a model system that target contributes to malignant phenotype - Evidence of reversal of malignant phenotype; by for example gene KO, dominant negative, antisense, RNAi, antibodies, peptides, drug leads - Availability of a robust efficient biological test cascade to support drug discovery program - Ability to run a robust cost-effective HTS - Availability of a structure-based drug design approach

Answer 103

Small molecule drug inhibitor of Bcr-AbI tyrosine kinase that acts in CML leukemia and Ph+ ALL. Inhibits proliferation of cancer and induce cancer cell death. Took 40 years to develop Chronic dosing needed to maintain inhibition of target.

Answer 104

Growth factor receptor Expressed in several human tumors in varying percentage.

Answer 105

Inhibition of EGFR-TK in the cell inhibits EGFR-TK signalling independent from induction. For example Iressa and Tarceva. Give cancer cell death and stop cancer cell division For Iressa treatment only carriers of mutation of EGFR receptor responsive

Answer 106

Basket/bucket trials - Single drug targeting a single mutation Umbrella trials - Multiple drugs targeting multiple mutations Exceptional responder trials - Any cancer types and drug where's a patient had an unusually robust clinical benefit

Answer 107

PARP - acts to repair broken DNA. Binds rapidly and directly ss breaks, once bound, modifies itself producing large branched changed of Poly, then recruits repair enzymes and gives repaired DNA. Inhibiting PARP has been shown to have a synthetic lethal effect with defects in certain DNA repair pathways, such as BRCA1 or BRCA2. This has led to the development of PARP inhibitors as a potential treatment for certain types of cancer, such as breast and ovarian cancer, that have defects in these DNA repair pathways.

Answer 108

Retinoblastoma tumors have not genetic inactivation of p53. MDM2 and MDMX proteins control p53 in the cell. MDMX gene amplified in these particular tumors. Nutlin-3 is a drug that can be used to reduce amount of MDM2 and MDMX. With nutlin 3 and topotecan the relative amount of bound MDM2 and MDMX overtime decreases a lot.

Answer 109

Phage display

Answer 110

– Choice of target antigen (cancer specific, limit cross reactivity healthy tissue - all cancer cells should carry it – Antigens which are shedded from the cell surface not preferable) – Immunogenecity of the antibodies (induction of human anti-mouse ab (HAMA’s) – Penetration in solid tumors (endothelial barrier, stromal and epithelial barriers and high interstitial pressure) – Half life of antibody – Ability of antibodies to recruit immune effector functions (to overcome this humanized (chimeric) ab have been engineered. This is a human antibody with a complementarity determining region (CDR) of another species (95% human/5% mouse)

Answer 111

- Large protein complex responsible for degradation of proteins in cells - Involved in wide range of biological processes - Dysregulation linked to number of diseases

Answer 112

- Major pathway for degradation of proteins in cells - Ubiquitination; marks protein for degradation and targets to the proteasome , a large complex within cells breaking down proteins into their constituent aa. - Dysregulation linked to number of dieseses

Answer 113

Nf-kappaB is a transcription factor that plays a central role in regulating the immune response and inflammation in the body. It is activated in response to various stimuli, including stress, inflammation, and infection, and plays a role in the expression of genes involved in immune and inflammatory responses. Dysregulation of Nf-kappaB signaling has been linked to a number of diseases, including cancer, autoimmune disorders, and inflammatory diseases.

Answer 114

PS-341, also known as bortezomib, is a medication that is used to treat multiple myeloma, a type of blood cancer that affects plasma cells in the bone marrow. It belongs to a class of medications called proteasome inhibitors, which work by inhibiting the activity of the proteasome, a complex in cells that breaks down proteins. By inhibiting the proteasome, PS-341 disrupts the degradation of certain proteins that are involved in cancer cell survival and proliferation, leading to the death of cancer cells. PS-341 is usually administered intravenously as part of a combination chemotherapy regimen. It has been shown to be effective in the treatment of multiple myeloma and has also been studied for the treatment of other types of cancer. Drug has passed phase III. It is still unclear which, if any, are the key substrate proteins of the 26S proteasome in response to PS-341. NF-kB signalling is dependent on proteasome activity – might explain the induction of apoptosis by PS-341 – especially in myeloma PS-341 is reducing tumor replication, angiogenesis and fostering apoptosis Future will focus on additional targets as the specific ubiquitin ligsaes involved in the degradation of oncogenic and cell cycle control proteins

Answer 115

Cancer treatment using viruses that have natural tropism for cancer cells. Still an experimental treatment, is studied in clinical trials. Several viruses in clinical trials, pRB and p53 pathway interactions with adenoviral gene products among those studied.

Answer 116

The new holy grail of cancer therapy? RNAi is an interplay of initiator DICER and effector RISC - RNAi, or RNA interference, is a natural process that occurs in cells and is involved in the regulation of gene expression. - It works by degrading specific mRNA molecules, preventing them from being translated into protein. - RNAi can be triggered by the introduction of small RNA molecules, called small interfering RNAs (siRNAs), into cells. These siRNAs can be designed to specifically target the mRNA of a particular gene --> degradation of that mRNA and the suppression of the corresponding protein.

Answer 117

RNAi has potential as a cancer therapy because many cancer cells have altered gene expression patterns that contribute to their uncontrolled growth and proliferation. By targeting specific genes with RNAi, it may be possible to inhibit the growth and survival of cancer cells. RNAi is still an experimental treatment and is being studied in clinical trials for a variety of cancer types. It has shown some promise as a cancer therapy, particularly in combination with other therapies, but more research is needed to determine its safety and effectiveness.

Answer 118

CTLA4 mediated immune checkpoint induced in T-cells by initial response to antigen. High affinity TCR ligands give higher level of CTLA4. CTLA4 lowers the signal of Tcells to maintain a constant level. Ipilmumab blocks CTLA-4, which prevent the T-cells inhibition.

Answer 119

Major role of PD1 is to regulate inflammatory response in tissue by effector T-cells recognizing antigen in peripheral tissue. Activated T-cells upregulated PD1. -Some tumour cells arm themselves with a shield of molecules called PD-l1. Lymphocytes possess PD-1 receptors which, by bonding to these traps, destroy their capacity to attack

Answer 120

PD-1 Inhibitors CTLA-4 inhibitors PD-L1 inhibitors - T-lymphocytes are the cells of the immune system identifying tumour cells and destroying them. -Some tumour cells arm themselves with a shield of molecules called PD-l1. Lymphocytes possess PD-1 receptors which, by bonding to these traps, destroy their capacity to attack - The new drugs based on antibodies block PD-1 from the cells of the immune system and PD-L1 from tumour cells to prevent their fatal action - Lymphocytes, once freed from their blindness of the drug, regain defence pontential. Recognice cancer and reduce it.

Answer 121

* To increase response rates and overcome resistance combinations of different checkpoint inhibitors have been made: * Checkmate trial 067: nivolumab + ipulimumab combination treatment resulted in a higher response rate and longer progression free survival compared to ipulimumab alone. * 3 year overall survival: 58 % nivolumab + ipulimumab ; 52 % nivolumab, 34% ipulimumab * Treatment related adverse events occured in 59 % of the nivolumab + ipulimumab group and only 21% in the nivolumab and 28% in the ipulimumab group.

Answer 122

TIL stands for "tumor-infiltrating lymphocytes." TILs are immune cells that have migrated into a tumor and are thought to play a role in the body's immune response to cancer. Some researchers are studying TILs as a potential therapy for cancer, with the idea being to isolate TILs from a patient's tumor, grow them in the lab, and then reinfuse them back into the patient in an effort to boost the patient's immune response to the cancer. This approach is still in the early stages of research, and it is not yet clear how effective it will be as a treatment for cancer.

Answer 123

1. Get blood with T-cells from patient 2. Create CAR-T cells that react to cancer cells 3. Grow many CAR T cells 4. Inject CAR T Cells into patient 5. CAR T cells attack cancer cells The same can also be done with NK-cells