Molecular Cell Biology Bio 5068 Cancer Oncogenes Tumor

Molecular Cell Biology (Bio 5068) Cancer: Oncogenes, Tumor Suppressor Genes And the Tumor Microenvironment Ron Bose, MD Ph. D Assoc. Professor of Oncology, WUSM December 6, 2019

Outline 1. Cancer as a Cellular Disease a. Oncogenes b. Tumor Suppressor Genes c. The Cancer Genome Atlas (TCGA) project 2. Cancer at the Tissue Level – the Microenvironment a. Immunotherapy for Cancer – 2018 Nobel Prize

Definitions 1. Oncogenes are Gain of Function (GOF) events in Cancer a. Typically are genetically Dominant events 2. Tumor Suppressor Genes are Loss of Function (LOF) events in Cancer a. Typically are genetically Recessive events

Definitions

Mechanisms to create an Oncogene 1. Mutation (GOF/Activating) 2. Gene Amplification 3. Chromosomal Translocating that is GOF 4. Viral Oncogenes – Human Papilloma Virus (HPV) – Retroviruses

HPV Oncogenes Outline

Ras genes are Commonly Mutated Oncogenes • KRAS – mutated in: 40% of colorectal cancer 50% of lung cancers 90% pancreatic cancers ON • HRAS – seen in bladder cancer. • NRAS – mutated in: 10% of leukemias

Mechanisms to inactivate a Tumor Suppressor Gene 1. Mutation a. LOF mutations b. Truncating mutations – frameshift or nonsense mutations 2. Gene Deletion 3. Chromosomal Translocation 4. Inherited loss of 1 copy + somatic loss of 2 nd copy Example: RB 1 Retinoblastoma

Retinoblastoma

Loss of Heterozygosity

The 20/20 rule of thumb – Genetics of Oncogenes/TSG’s Notice the clustered missense/point mutations >20% mutations are Truncating Mutations, ie-frameshift or nonsense mutations

The 20/20 rule of thumb – Genetics of Oncogenes/TSG’s c. Bio. Portal Data on 46, 588 patient cancers Is this an Oncogene or a TSG? 1000 cases 620 cases 1344 cases Is this an Oncogene or a TSG?

The 20/20 rule of thumb – Genetics of Oncogenes/TSG’s c. Bio. Portal Data on 46, 588 patient cancers Is this an Oncogene or a TSG? HER 2 (gene symbol ERBB 2) Is this an Oncogene or a TSG? Bose et al. , Cancer Discovery 2013

HER 2 Alterations in Colorectal Cancer Any HER 2 alterations in colorectal cancer 14/212 = 7% Ampli fication Mutations 6 212 3 212 5 212 V 777 L 2 patients L 755 S S 310 F I 263 T V 842 I 4 patients A 466 T R 678 Q R 868 W N 1219 S Kavuri et al. , Cancer Discovery, 2015

HER 2 Mutations Transform Colonic Epithelial Cells HER 2 WT V 777 L V 842 I L 755 S S 310 F Kavuri et al. , Cancer Discovery, 2015

HER 2 Mutations Cause Resistance to Anti-EGFR Monoclonal Antibodies A Cetuximab B Panitumumab DIFI cells NCI-H 508 cells C D IC 50 (ug/ml) Parental HER 2 -WT V 842 I L 866 M L 755 S V 777 L S 310 F 0. 42 +/- 0. 04 1. 30 +/- 0. 10 > 70 > 200 IC 50 (ug/ml) Parental HER 2 -WT V 842 I L 866 M L 755 S V 777 L S 310 F 0. 18 +/- 0. 02 0. 31 +/- 0. 03 > 70 > 200 Kavuri et al. , Cancer Discovery, 2015

HER 2 Mutant Colon Cancer Cells are Very Sensitive to Neratinib and Afatinib Kavuri et al. , Cancer Discovery, 2015

HER 2 mutant Colorectal Patient Derived Xenografts PDX M 051. HER 2 L 866 M + amplification 2200 Placebo 2000 Tumor Size (mm 3) 1800 Trastuzumab 1600 Neratinib 1400 1200 Trastuzumab+ Neratinib 1000 800 600 400 200 0 -20 -15 -10 -5 0 5 10 15 20 25 30 Time (days) Kavuri et al. , Cancer Discovery, 2015

Genetic Alterations in APC, KRAS lead to development of Colorectal Cancer (CRC) BOTTOM LINE: No One Gene causes Cancer. Cells need a series of TSG loss and Oncogene activation events to become Cancerous Other alterations: HER 2, PIK 3 CA Dr. Bert Vogelstein Ludwig Professor of Oncology at Johns Hopkins School of Medicine

Cells need a series of TSG and Oncogene changes to form Cancer

For many cancers, their most dangerous feature is their ability to metastasize to other parts of the body. Many cancer patients die because of the mets, not the primary site of cancer.

The NIH TCGA Project has provided Amazing Understanding of the Gene Changes in Cancer 30+ back to back articles providing the final analysis of the TCGA project were published in the April issues of Cell, Cancer Cell, and Cell Systems

How to Access and Search TCGA Data

Outline 1. Cancer as a Cellular Disease a. Oncogenes b. Tumor Suppressor Genes c. The Cancer Genome Atlas (TCGA) project 2. Cancer at the Tissue Level – the Microenvironment a. Immunotherapy for Cancer – 2018 Nobel Prize

Cancer at the Tissue Level

Cancer at the Tissue Level Cancer associated fibroblasts (CAF) having an important interaction with the cancer cells

Cancer at the Tissue Level – Microenvironment is Different at a Site of Metastasis

Cancers often Suppress T-Cell Responses

Conclusions 1. Oncogenes are Gain of Function/Dominant Gene changes in Cancer 2. Tumor Suppressor Genes are Loss of Function/Recessive gene changes in Cancer 3. There is NO ONE gene for cancer. Cancer is caused by a series of Oncogene and Tumor Suppressor Gene alterations. 4. The tumor microenvironment influences the behavior of the cancer cell. When cancers metastasize, they have to adapt to a new microenvironment. 5. Understanding how cancer cells interact with another cell type, the Tlymphocyte, led to a new treatment for cancer, called Immunotherapy (IO) or more precisely, Immune Checkpoint Blockade.