Mutations and Cancer

Question 1

How to somatic cells and germline cells differ? How would mutations in these cells affect the individual? The offspring of the individual?

Answer 1

Cells that are not in the germline are called somatic cells. This refers to all the cells of the body apart from the gametes. If there is a mutation or other genetic change in the germline, it can be potentially passed to the offspring, but a change in a somatic cell will not be.

Question 2

What is cancer? what role do oncogenes and tumor-suppressor genes play in the formation of cancer? What are checkpoint proteins and what is their role in the cell cycle and cancer? What causes cancer? What are the hallmarks of cancer?

Answer 2

Abnormal cells divide without control and are able to invade other tissues. Cancer cells can spread to other parts of the body through the blood and lymph systems.

Oncogenes are mutations of normal genes called “proto-oncogenes.” These “proto-oncogenes” control what kind of cell it is and how often it divides. When this gene mutates into an oncogene, it becomes a bad gene that can become permanently turned on or activated when it is not supposed to be. Tumor suppressor genes are normal genes that slow down cell division, repair DNA mistakes, or tell cells when to die (apoptosis). When tumor suppressor genes don’t work properly, cells can grow out of control, which can lead to cancer.

Cell cycle checkpoints are control mechanisms that ensure the fidelity of cell division in eukaryotic cells. These checkpoints verify whether the processes at each phase of the cell cycle have been accurately completed before progression into the next phase.

Question 3

Describe the significance of p53

Answer 3

p53 is a tumor suppressor protein that in humans is encoded by the TP53 gene. p53 is crucial in multicellular organisms, where it regulates the cell cycle, and thus functions as a tumor suppressor that is involved in preventing cancer.

Question 4

What are the current tools used to screen, diagnose and treat cancer?

Answer 4

Imaging Cancer for Screening – label with fluorescent probe and run through microfluidic device to count cancer cells: probing cancer cells

Diagnose
Test to confirm cancer
Biopsy-remove a sample of cells and complete a microscopic evaluation (can determine type of cancer and grade of cancer (stage 1-4))
Gene sequencing to determine therapeutic route

Treatment
Radiation and Chemotherapy (damage or destroy rapidly dividing cells)
Targeted Therapy (Target receptors – ex. Selective estrogen receptor modulators (SERM) – Tamoxifin)

Question 5

what are molecular and immuno-therapeutic treatments for cancer, why are the “better” than more traditional therapies? How are nanoparticles being used to treat cancer?

Answer 5

Molecular Therapy

• Inactivate oncogene product via immunotherapy
• Philadelphia chromosome: produces abnormal tyrosine kinase and increases cell division
• Gleevec: specifically targets TK and lead to 90% survival

Immunotherapy

• Harness body’s immune system to fight cancer
• Use a viral vector with engineered gene sequence to label cancer cells (may need to select multiple surface markers to be specific), induce the release of tumor antigens, prevent the formation of new blood vessels (anti-angiogenesis)

Nanoparticles

• apply antibodies to gold nanoparticles to target cancer cells
• use light (phototherapy) to selectively heat nanoparticles and kill cancer cells without affecting healthy cells
• use nanoparticles to specifically deliver chemotherapy-decrease multidrug resistance