Lecture 7 - Anticancer Meds Flashcards
Cancer
also known as a malignant tumor or malignant neoplasm, is a group of diseases involving abnormal cell growth with the potential to invade or to spread to other parts of the body
____ have a higher chance of getting cancer and a higher chance of dying earlier
men
List the 3 top cancers for men and women in Canada
Men:
1) Prostate
2) Colorectal
3) Lung
Women:
1) Breast
2) Lung
3) Colorectal
Cancer is primarily a disease of ____ age
old
Malignant
if tumor invades surrounding tissue (cancerous)
Benign
if tumor has no effect on surrounding tissue (non-cancerous)
Metastatic
if individual cells break away and start a new tumor elsewhere (cancerous)
Describe the path to cancer
-Clonal proliferation
-Starts from a single cell
-Expansion in steps
-Pre-malignant states
(Polyp, MDS, MGUS)
-Serial accumulation of mutations
(Clonal evolution, resistance)
List some hallmarks of cancer
- Self sufficiency in growth signals
- Insensitivity to anti-growth signals
- Evading apoptosis
- Limitless reproductive potential
- Sustained angiogenesis
- Tissue invasion and metastases
- Genomic instability
Is cancer a genetic disease?
Yes
Cancer arises from the accumulation of _____ changes (somatic mutations)
*Genetic selection at the level of single cells
genetic
Most cancers incur a minimum of ______ different gene mutations
5 (6-9)
We don’t inherit cancer but we do inherit _______ to cancer
dispositions (susceptibility)
_______ is a hallmark of cancer cells
Aneuploidy
What is aneuploidy?
The presence of an abnormal number of chromosomes in a cell
2 components of Etiology of cancer
Nature:
-What we inherit
Nurture
-Environmental factor (what we do to our body) ex. smoking, UV radiation, etc.
You need an _____ and an elongated promoter to lead to cancer
initiator
Tumor initiators = ______
mutagens
Tumor Promoters = _____ ______
proliferation inducers
List some tumor initiators (mutagens)
- X rays
- UV light
- DNA alkylating agents
List some tumor promoters (proliferation inducers)
- Phorbol esters
- Inflammation
- Alcohol
- Estrogens and Androgens
- Epstein-Barr Virus
Cell cycle phases:
G1 (gap phase)
the cell grows and prepares to synthesize DNA
Cell cycle phases:
S (synthesis phase)
in which the cell synthesizes DNA
Cell cycle phases:
G2 (second gap phase)
in which the cell prepares to divide
Cell cycle phases:
M (mitosis phase)
cell division occurs
Cell cycle phases:
G0 (arrest/quiescent)
cell is in resting state
Cell cycle phases:
Checkpoint 1
G1/S checkpoint:
Cell monitors size and DNA integrity
Cell cycle phases:
Checkpoint 2
G2/M checkpoint:
Cell monitors DNA synthesis and damage
Cell cycle phases:
Checkpoint 3
M checkpoint:
Cell monitors spindle formation and attachment to kinetochores
What protein complexes are involved in the cell cycle?
- Cyclins
- Cyclin dependent kinases (Cdks)
Are Cdk (cyclin dependent kinases) levels stable?
yes
Are cyclin levels stable?
no they change throughout the cell cycle
The ability to drive through the checkpoint are reliant on ??
cyclins and cdks (oncogenes)
*cdk = cyclin dependent kinase
Cdks must bind to the correct ___ in order to function
cyclin
What do kinases do?
enzymes that add phosphate groups to proteins to convert them from an “off” to an “on” state
Describe the pathogenesis of cancer:
_____ are activated
___ ______ ____ are inactivated
Oncogenes are activated
Tumor suppressor genes are inactivated
Oncogene = ?
gas pedal
Tumor suppressor genes = ?
brakes
What is p53?
a class tumor suppressor
What is Rb?
also a classic tumor suppressor
Rb binds to a protein called ____
E2F1
*when bound to Rb, E2F1 can’t function
_______ = drives cell cycle forward and bypasses checkpoints
Oncogenes
______ = an amplified oncogene
HER2/neu
*a growth factor receptor
25-30% of ____ cancers over-express HER2/neu
breast
____ is used as a treatment for breast cancers that over-express HER2/neu
Herceptin
___ = a frequently mutated oncogene
Ras
Translocations can be ? (2)
- Balanced
- Reciprocal
Aneuploidy can be ? (4)
- Pseudodiploid
- Hyperdiploid
- Complex
- Random loss or gain
- Loss of tumor suppressor function
- Proto-oncogenic gain of function (into oncogene)
What is the Philadelphia chromosome?
- Translocation between chromosome 22 and chromosome 9
- Classic oncogenic rearrangement associated with a variety of leukemias
- BCR-ABL tyrosine kinase fusion
- Imatinib (Gleevec) is an Abl-kinase targeted tyrosine kinase inhibitor (TKi) used in the treatment of the Ph+ CML and other tumors
When is chemotherapy most effective?
when growth fraction is high
Describe early stages of tumour growth?
- high growth fraction
- short doubling times
Describe late stages of tumour growth?
- low growth fraction
- long doubling times
Benign = ?
non-cancerous
“polyp”
Malignant = ?
cancerous
Malignant epithelial = ?
carcinoma
Malignant mesenchyme = ?
sarcoma
Malignant hematopoietic = ?
leukemia, lymphoma, myeloma
Hyperplasia
increased number of cells
Hypertrophy
increased size of cells
Dysplasia
disorderly proliferation
Neoplasia
abnormal new growth
Anaplasia
lack of differentiation
Tumor
originally meant any swelling, but now equated with neoplasia (abnormal new growth)
Metastasis
growth at a distant site
Bening tumor ends in “___”
“oma”
ex. adenoma
ex. fibroma
ex. lipoma
Malignant cancer ends in ______ or ______
carcinoma or sarcoma
ex. adenocarcinoma
ex. fibrosarcoma
ex. liposarcoma
ex. leukemia and lymphoma (don’t follow the rule wtf)
Describe the stages of tumor progression
- Hyperplasia
- Dysplasia
- Carcinoma in situ (not cross the basal lamina)
- Cancer (malignant tumors) - Metastasis
_____ = non-invasive
benign
_____ = invasive/metastatic
malignant
How do we classify cancers?
Grade - How bad do the cells look?
Stage - Where has the cancer spread?
T = Tumour N = Nodes (Lymph) M = Metastases
Grade 1 Cancer
Well differentiated
Grade 2 Cancer
Moderately differentiated
Grade 3 Cancer
Poorly differentiated
Grade 4 Cancer
Anaplastic (now all the cells look really different)
As the cancer stage increases, survival rates ____
decrease
If cancer spreads to another part of the body, it keeps it’s old _____
name
For ex. if kidney cancer spreads to the lungs, it is called kidney cancer which has metastasized to the lung
List some cancer factors affecting outcome
- Growth fraction
- Doubling time
- Type
- Stage
- Resistance
List some patient factors affecting outcome
- Overall health
- Bone marrow capacity
- Liver function
- Kidney function
- Age
- Compliance
Describe radiation
- Ionization and excitation of atoms that kills cells
- Cell killing, nausea, vomiting, fatigue, somnolence
- Late effect; fibrosis and gliosis
- Skin and mucosal reactions are accentuated by other modalities like chemotherapy
-Definitive, adjuvant, palliative
Purpose of primary chemotherapy
shrink of eliminate tumor
Purpose of neoadjuvant chemotherapy
make tumor more amenable to other therapies
Purpose of adjuvant chemotherapy
eradicate micro metastasis
Purpose of palliation chemotherapy
symptom control
What does CR Response to chemotherapy mean?
complete disappearance for at least 1 month
What does PR Response to chemotherapy mean?
50% of > reduction in tumor size or markers and no new disease for 1 month
What does SD Response to chemotherapy mean?
no reduction or growth
What does Progression Response to chemotherapy mean?
25% increase in tumor size
What are some cell cycle specific agents?
- antimetabolites
- vinca alkaloids
What are some cell cycle non-specific agents?
- doxorubicin
- cisplatin
Drugs that act only on a specific portion of the cell cycle (CCS) drugs will be least effective at treating cancers who have ____ growth fractions
low
It is common to follow treatment with a _____ drug with a ____ drug so that cancer cells are recruited into the cell cycle, where CCS drugs can be more effective
follow treatment with a NCCS drug with a CCS drug
CCS:
Plant alkaloids target which phase?
G2-M
CCS:
DNA synthesis inhibitors target which phase?
S
CCS:
They are ____ dependent (duration and timing more important than dose)
scheduele
CCS:
Only ___ cells killed
proliferating (high growth factor tumors preferentially eliminated)
NCCS:
What cells are killed?
Both proliferating and non-proliferating cells are killed (attack both high and low growth factor tumors)
NCCS:
They are ___ dependent (total dose is more important than schedule)
dose
Why are cancer chemotherapeutics typically given in cycles?
to allow normal cells time to recover from the treatment
Fractional kill hypothesis:
In order to reduce the impact of the recovery/resistance problem, the key principles to antineoplastic drug therapy are:
? (3)
- Use high doses (including increasing doses during treatment; called DOSE ESCALATION)
- Minimize recovery intervals (cell kill hypothesis)
- Employ sequential scheduling during combination therapy
What are some critical factors to treatment?
- Early start to the treatment
- Treatment must continue past the time when cancer cells can be detected using conventional techniques
- Appropriate scheduling of treatment courses and care to ensure sufficient log-kill is obtained are also crucial factors that enable success
List 3 types of chemotherapy treatments
1) Inhibitors of cell growth (Growth Factor Proteins ex. hormones)
2) Inhibitors of DNA Duplication
3) Inhibitors of Cell Division
Describe the wide range of drugs for chemotherapy
1) Non cell cycle dependent (Genotoxic agents)
2) Cell cycle dependent
- Cytoskeletal inhibitors
- Topoisomerase inhibitors
- Antimetabolites
- Hormonal therapy
3) Others
What drugs are cell-cycle independent?
- Platinating agents
- Alkylating agents
What drugs target S phase?
- Vinca alkaloids
- 5-fluorouracil
- Methotrexate
- Hydroxyurea
- Doxorubicin
- Cytarabine
- Gemcitabine
- Etoposide
What drugs target G2 phase?
-Bleomycin
What drugs target M phase?
- Taxanes
- Vinca alkaloids
- Etoposide
look at slide 82 for a review man
omg if i have time man
Genotoxic agents are ?
non cell-cycle specific
NCCS
Anti-metabolites target __ phase
S
Cytoskeletal inhibitors target _____ phase
mitosis
Topoisomerase inhibitors target ___ phase
G2
Steroid hormones target ___ phase
G1
Genotoxic Agents (NCCS): MOA
- affect the function of nucleic acids
- bind directly to DNA
- inhibit DNA replication enzymes
- DNA damage leads to apoptosis
- *prevent the separation of strands
- *Induce mispairing that renders them non-functional
Genotoxic Agents (NCCS): Include \_\_\_\_\_ and \_\_\_\_\_\_ agents
Include alkylating and intercalating agents
Genotoxic Agents (NCCS): List the most common genotoxic agents
1) Platinum based chemotherapeutic agents:
- cisplatin
- carboplatin
- xaliplatin
2) Doxorubicin analogs
3) Cyclophosphamide-pro drug, orally active, less side effects in normal cells
Describe Antimetabolites (S phase - CCS):
- Structurally similar to natural metabolites
- Prevents cells from carrying out vital functions and they are unable to grow and survive
- Interfere with the production of nucleic acids, RNA and DNA
- If new DNA cannot be made, cells are unable to divide !!!
Antimetabolites (S phase - CCS):
List some
1) Folate antagonists
ex. Methotrexate
2) Purine antagonists
ex. Thiopurine methyltransferase
3) Pyrimidine antagonists
ex. 5-Fluorouracil
Antimetabolites (S phase - CCS):
Describe folate antagonists
Ex. Methotrexate
- Folate antagonists inhibit dihydrofolate reductase, an enzyme involved in the formation of purine and pyrimidine nucleotides for DNA synthesis
- Without DNA replication, cell growth is blocked
Antimetabolites (S phase - CCS):
Describe the next generation Folate Antagonist
Permetrexed:
- Inhibits DHFR
- Inhibits thymidylate synthase (TS)
- Inhibits glycinamide ribonucleotide formyl transferase (GRFT)
*More effectively inhibits DNA and RNA synthesis
Antimetabolites (S phase - CCS):
Describe folinic acid
Folinic Acid (Leucovorin):
- Used with methotrexate and antifolates to reduce (rescue therapy) myelosuppresion (often the most significant dose limiting adverse rx)
- THF analog that can be used as a methyl donor
- DHFR insensitive
Antimetabolites (S phase - CCS):
Purine Antagonists:
MOA
Purine antagonists prevent continued replication of DNA, and therefore cell division:
6-Mercaptopurine (6-MP) - looks like Adenine
6-Thioguanine (6-TG) - looks like Guanine
Antimetabolites (S phase - CCS):
Purine Antagonists:
Describe thiopurine methyltransferase (TPMT)
- Metabolism of thiopurine drugs such as azathioprine, 6-Mercaptopurine and 6-Thioguanine
- TPMT catalyzes the S-methylation of thiopurine drugs
- Defects in the TPMT gene leads to decreased methylation and decreased inactivation of 6MP leading to enhanced bone marrow toxicity which may cause myelosuppresion, anemia, bleeding tendency, leukopenia & infection
Antimetabolites (S phase - CCS):
Purine Antagonists:
What does TPMT polymorphism result in?
As TPMT is a deactivation pathway, the result is more active drug, increased toxicity (similar to an overdose situation)
Antimetabolites (S phase - CCS):
Pyrimidine antagonists:
MOA
-Block synthesis of pyrimidine containing nucleotides
(dCTP and dTTP in DNA; CTP and UTP in RNA)
-Stop DNA/RNA synthesis and inhibit cell division
Antimetabolites (S phase - CCS):
Pyrimidine antagonists:
List some pyrimidine Antagonists used in cancer therapy
1) 5-Fluorouracil (5-FU)
2) Cytarabine (cytosine arabinoside, ARA-C)
Antimetabolites (S phase - CCS):
Pyrimidine antagonists:
MOA of 5-FU
inhibit thymidylate synthase
which prevents cell growth probs
What is the mitotic spindle?
attaches to kinetochores, helps align chromosomes and then separates them
What is MAD and BUB?
Part of the spindle checkpoint that halt the cell cycle until all chromosomes are aligned at the middle of the cell
Cytoskeletal inhibitors (Mitosis phase): List 2 drugs affecting this category
Taxanes:
- Paclitaxel
- Docetaxel
Vinca alkaloids:
- Vincristine
- Vimblastin
- Vindesine
Cytoskeletal inhibitors (Mitosis phase): How do they work?
- Affect the mechanics of cell division
- Without proper microtubule formation, cell division is not possible
Cytoskeletal inhibitors (Mitosis phase):
How do Taxanes (Paclitaxel, Docetaxel) work?
- affect anaphse
- affect depolymerization
Cytoskeletal inhibitors (Mitosis phase):
How do Vinca alkaloids (Vincrinstine, Vimblastin, Vindesine) work?
- affect metaphase
- affect polymerization
Cytoskeletal inhibitors (Mitosis phase):
Main side effect of taxanes?
female infertility by ovarian damage
Topoisomerase 1 inhibitors (G2 phase):
What do Topoisomerase inhibitors do?
Topoisomerase (Top1) inhibitors interfere with the action of topoisomerase enzymes (Top 1 and 2), which are enzymes that control the changes in DNA structure by catalyzing the breaking and rejoining of the phosphodiester backbone of DNA strands during the normal cell cycle.
Blocks the ligation step of the cell cycle, generating single and double stranded breaks that harm the integrity of the genome = apoptosis and cell death
Topoisomerase 1 inhibitors (G2 phase):
List some
Topotecan
Irinotecan
Topoisomerase 2 inhibitors (G2 phase):
List some
Etoposide
Teniposide
Steroid hormones (G1 phase):
Describe the MOA
1) Steroid hormone enters target cell
2) Hormone binds to receptor, induces conformational change
3) Hormone-receptor complex binds to DNA, induces start of transcription
4) Many mRNA transcripts are produced, amplifying the signal
5) Each transcript is translated many times, further amplifying the signal
Steroid hormones (G1 phase):
Hormone Therapy
Objective ?
starve cancer cells from hormonal signals necessary for growth
Steroid hormones (G1 phase):
Hormone Therapy
Approach ?
- hormone blocking drugs at target cells
- prevent hormone production
Steroid hormones (G1 phase):
List some types of hormonal antagonists
1) Selective estrogen receptor modulators (SERMs)
2) Aromatase Inhibitors (AIs)
3) Selective androgen receptor modulators (SARMs)
Steroid hormones (G1 phase):
SERMs:
ER = ?
positive breast cancer cells
Steroid hormones (G1 phase): SERMs:
List some
- Tamoxifen
- Raloxifene
- Toremifene
*If you’re ER negative, these drugs won’t work for you ?
Steroid hormones (G1 phase): SERMs:
MOA
inhibition of estrogen’s growth stimulating effects
Steroid hormones (G1 phase): SERMs:
Describe Tamoxifen Chemotherapy
- Anti-estrogen affinity is dependent on primary metabolite, endoxifen (100x more active)
- CYP2D6 enzyme is responsible for metabolism of tamoxifen
- Can’t give endoxifen alone
- Have to give tamoxifen and then have the other rxns in liver happen, and have tamoxifen converted into endoxifen
Steroid hormones (G1 phase): SERMs:
Tamoxifen main DDI ?
Antidepressants
- paroxetine
- fluoxetine
- bupropion
Steroid hormones (G1 phase): Aromatase Inhibitors:
List some
Exemestane
Anastrozole
Letrozole
Steroid hormones (G1 phase): Aromatase Inhibitors:
MOA
Prevents conversion of hormones into estrone and estradiol
Steroid hormones (G1 phase):
Specific Androgen Receptor Modulators (SARMs):
List some
Flutamide
Bicalutamide
*Competitively bind AR
Principles of drug selection for combination therapy?
- active when used alone
- different mechanisms of action (including different mechanisms for the development of resistance) and/or different chemical classes
- NCCS vs CCS or active in different stages of cell cycle
- different toxicities
Combination therapy can result in?
- Synergistic effects (ex. Cytarabine and 6-Thioguanine)
- Decreased development of resistance
- Broader cell kill in cancers that consist of a heterogenous tumour cell population
List some adverse effects of chemotherapy drugs
Bone marrow depression
- Anemia
- Bleeding
- Infections
- Secondary cancers (Procarbazine)
Teratogenesis
Carcinogenesis
Resistance
How can we tell there is resistance to Methotrexate?
Increased concentrations of DHRF enzyme in cancer cells (gene amplification)
What is P-glycoprotein?
- First multi drug resistance mechanism to be characterized
- P-glycoprotein is transmembrane ATP-dependent efflux pump
- Actively transports many types of chemotherapy from cells
- Overexpression in cancers causes drug resistance
- P-glycoprotein inhibitors tested in clinical trials
List 5 forms of resistance mechanisms to chemotherapy
1) Increased expression of target proteins
2) Failure of the drugs to enter cancer cell or increased intracellular drug ejection rate
3) Drugs fail to reach target cells
4) The target molecule is no longer present
5) The target molecule is altered (mutation/deletion)
List 3 drugs involved in Monoclonal Antibody Therapy?
- Rituximab
- Trastuzumab
- Cetuximab
Monoclonal Antibody Therapy:
Describe Rituximab
- binds to CD20 antigen (receptor) present on the cell surface of B-lymphocytes
- binding to CD20 targets the cell to complement-activated phagocytosis and antibody-dependent apoptosis
- inhibit proliferation of lymphocytes and lymphoma cells
Monoclonal Antibody Therapy:
Describe Trastuzumab
-binds to human epidermal growth factor receptor protein-2 (HER2)
Monoclonal Antibody Therapy:
Describe Cetuximab
-chimeric (mouse/human) monoclonal antibody against epidermal growth factor receptor protein (EGFR)
List 2 antibody-drug conjugates
Brentuximab vedotin
Trastuzumab emtansine