The biology of ERK presentation power point presentation

The biology of ERK presentation power point presentation

1. ERK/MAPK SIGNALIING PATHWAY AND PI3K/AKT/MTOR PATHWAY GROUP MEMBER: GEOFFREY OGETO- GMOP/M/4078/09/24 Namaru N Peter- GMOP/M/3858/09/24 Joy Njeri- GMOP/M/4104/09/24 Neha Ashok Bilakhia- GMOP/M/4091/09/24

2. OBJECTIVES MECHANISM OF ERK/MAPK PATHWAY MECHANISM OF PI3K/AKT/MTOR PATHWAY ANLAYZING THE ROLE OF THESES MECHANISMS IN CANCER THERAPEUTICS. ARE WE MAKING HEADWAY?

3. ERK-MAPK PATHWAY

4. ERK/MAPK SIGNALING Extra cellular signal- regulated kinase 1/2 (ERK) belongs to the mitogen-activated protein Kinase family, which plays a role in signaling cascades and transmits extracellular signals in a sequential activation of 3-4 layers of protein kinases known as MAP4k, MAP3K, MAP2K AND MAPK. The extracellular signal/ligand-( epidermal growth factor , tyrosine kinase a/b, insulin and many more) binds to the tyrosine kinase receptor present on the cytoplasmic membrane triggering dimerization of the kinase which leads to activation of the receptor. There is also auto phosphorylation of the tyrosine kinase receptor (TRK) on tyrosine domain leading to a SHC protein to attach to the phosphorylated TRK causing translocation of growth factor receptor-bound protein 2 (Grb2) from nucleus to cytoplasm which can be blocked by PTEN .

5. CONT’ Where the Grb2 attaches and gets to the SHC protein and in-turn gets phosphorylated allowing SOS (son of sevenless ) to attach to the active GRB2 forming a complex Grb2-SOS complex. Ras is a small G protein and product of Ras oncogene. RAS acts an upstream activating protein in MAP4K layer and RAF being a protein kinase specifically a MAP3K protein. RAS in its inactive state is RAS-GDP and in its active state is RAS-GTP the activation is caused by activated Grb2-SOS complex as SOS is a guanosine nucleotide exchanger factor that mediates removal of GDP to GTP. Raf-1 plays an important role in RAS/RAF/MEK/ERK cell proliferation signaling pathway. B-RAF a subtype of RAF is the strongest Kinase and has the highest mutation rate.

6. CONT’ RAS activates RAF by phosphorylation on catalytic domain activating a down stream MEK/MAPK signaling pathway. Mitogen activated protein kinase (MEK) MEK 1/2 protein kinase that gets phosphorylated by active RAF. MEK is dual phosphorylated at serine and threonine or serine aa this specificity avoids errors in the ERK activation. ERK is protein kinase in the MAPK layer MEK 1/2 catalysis dual phosphorylation of ERK which causes translocation of ERK to cytoplasm. The activated ERK1/2 gets transferred to nucleus and regulates transcription factors through phosphorylation. This transcription factors include C-FOS proto-oncogene While through the MEKK4/7 pathway regulates transcription factors C-JUN are activated MEKK 3/6 pathway regulates transcription factors ATF2 and P53. MEKK2/3 and MEK5 regulate transcription factors NUR 77. The binding induces gene expression and regulate cell proliferation, apoptosis, differentiation, transcription.

7. Where does ERK/MAPK pathway regulate the cell cycle? In most cells, some form of sustained ERK activity is required for cells to activated genes that induce cell cycle entry and suppress negative regulators of the cell cycle entry. Two important targets include cyclin D complexes cdk4 and cdk6 which are phosphorylated by ERK. The transition from G1 to S is coordinated by cyclin D complexes through hypo-phosphorylated retinoblastoma protein (RB), normally bound to E2F TF which inhibits transcription activity. When there is uncontrolled exposure to extracellular signals the E2F is activated and the cell cycle is uncontrolled.

8. TUMORGENESIS ERK 1/2 signaling pathway is involved in Cell survival Promotes proliferation lack of apoptosis Invasion and metastasis of tumor cells occur in three stages Adhesion- tumor cells break away from primary tumor and adhere to basement membrane. Degradation-become invasive Migration- enter the blood stream to target organs. GABRP exhibited significantly increased cell migration and invasion and ERK activation.

9. PI3K/AKT/MTOR PATHWAY The ligand or the extracellular signal-( epidermal growth factor , tyrosine kinase a/b, insulin and many more) binds to the tyrosine kinase receptor present on the cytoplasmic membrane on binding causes dimerization of the kinase which leads to activation of the receptor. There is also auto phosphorylation of the tyrosine kinase receptor (TRK) on tyrosine domain leading to a IRS protein to attach to the phosphorylated TRK causing phospho- inositide 3 kinase (PI3K). PI3K contains 2 domains the P85 domain which is the regulatory domain and the p110 domain which is the catalytic domain on attachment to IRS protein it is phosphorylated but is still not active as it requires RAS GTP to get activated. The active PI3K phosphorylates PIP2 (phosphatidylinositol(4,5) diphosphate )_phosphorylates position 3 of the inositol sugar to PIP3 phosphatidylinositol (3,4,5)-triphosphate position. PIP3 attaches with PDK 1/2 (Phospho-inositol dependent kinase1/2) which in turn phosphorylates PDK/AKT protein. PTEN converts PIP3 back to PIP2 making it a regulatory protein or a tumor suppressor. The activated PDK/AKT protein phosphorylates BAD a pro-apoptotic protein which is bound to BCL2 to detach. BCL2 prevents apoptosis and allowing cell survival. FOXO 3a another protein which binds to DNA and causes transcription of proapoptotic protein but on phosphorylation doesn’t allow transcription and leads to cell survival. GSK-3 β inhibits eif-2b which is responsible for initiation of translation on phosphorylation of GSK-3 β allowing eif-2b to initiated translation.

10. MTOR Activated PI3K/AKT/PKB inhibits TSC1/2 Tuberous sclerosis complex protein causing activation of RHEB GTP which is required for MTORC1 RICTOR activation. The activation of MTORC1 RICTOR causes the following Ribosome formation through the activation of RNA POL1 transcription factors. Increase translation of proteins and prevents protein degradation through S6- kinase and through inhibition of eif-4e protein responsible for inhibiting translation.

11. WHERE DOES PI3K/AKT/MTOR PATHWAY REGULATE THE CELL CYCLE It regulates the G1/S phase and G2/M phase either by direct phosphorylation of target proteins or indirectly by regulating protein expression levels. G1/S phase GSK3 that inhibits cyclin d complexes cdk4/6 become activated loss of P53 that causes activation cyclin E /cdk2 no apoptosis G2/M Normally Weel HU, Myt1 inhibit and cdc25b TF activates cyclin b but in uncontrolled exposure causes uncontrolled growth

12. Tumorigenesis Genetic mutations mainly occur on: PI3K- P110 catalytic domain mutation rate is 11-14% in cancers. Most prevalent seen in breast, endometrial cariconoma , uterine and cervical cancer, gall bladder and non-small lung call cancer and gastric. Mutation of PI3K-P110 causes cell proliferation and survival. 2. MTOR GENE- encodes the MTOR protein which results in continues protein activation, ribosome formation and increased translation i.e uncontrolled cell growth. 10% of melanomas have MTORC1 protein mutations and patients always have poor prognosis. Most MTORC1 mutations occur in endometrial cancers, renal cell and bladder cancers, colorectal carcinomas. Also MTOR C2 mutations. 3. AKT GENE- AKT1/2/3 mutations lead to cell survival, growth and migration. Occurance of AKT1 E17k in breast cancer is the highest and is also responsible for acceleration of resistance to chemotherapeutic agents and leads to variety of malignant tumors.

13. CONT’ 4 mutations of PTEN GENE- encodes PTEN (tumor suppressor) ensures PIP3 is converted to PIP2 preventing further activation of AKT/PDK protein. Dysfunction of PTEN is caused by inactivation mutations Homozygous deletions Loss of heterozygosity (LOH) Epigenetic modifications. All this lead to accumulation of PIP3 and activates catabolic downstream of AKB/MTOR pathway leading to cell proliferation, increased translation of proteins and proliferation, decrease in apoptosis. PTEN neddylation is closely associated with tumor development . PTEN mutations are found in approximately 80% of patients with breast and thyroid cancers, glioblastoma (29%) and prostate(30%).

14. CHEMOTHERAPEUTICS ARE WE MAKING HEADWAY?

15. PI3K/AKT/mTOR Pathway Inhibitors PI3K Inhibitors Alpelisib ( Piqray ) MOA : Alpelisib selectively inhibits the alpha isoform of PI3K (PI3K α), blocking PIP3 formation, reducing downstream AKT signaling, and inhibiting cancer cell growth. Pharmacologically relevant effects : Used in HR-positive, HER2-negative breast cancer with PIK3CA mutations. Adverse effects : Hyperglycemia, rash, diarrhea, decreased appetite, elevated liver enzymes.

16. PI3K/AKT/mTOR Pathway Inhibitors: p13K inhibitors 2. Idelalisib ( Zydelig ) MOA : Idelalisib selectively inhibits the delta isoform of PI3K (PI3K δ), reducing the proliferation of malignant B-cells. Pharmacologically relevant effects : Approved for chronic lymphocytic leukemia (CLL), small lymphocytic lymphoma (SLL), and follicular B-cell non-Hodgkin lymphoma. Adverse effects : Diarrhea/colitis, hepatotoxicity, pneumonitis, severe cutaneous reactions, neutropenia.

17. PI3K/AKT/mTOR Pathway Inhibitors: p13k inhibitors 3. Copanlisib ( Aliqopa ) MOA : Inhibits PI3K isoforms (both alpha and delta), blocking PIP3 production and downstream signaling. Pharmacologically relevant effects : Approved for relapsed follicular lymphoma. Adverse effects : Hypertension, hyperglycemia, pneumonitis, infections, diarrhea.

18. PI3K/AKT/mTOR Pathway Inhibitors cont : AKT INHIBITORS 1.CAPIVASERTIB: MOA : Selective inhibitor of AKT, preventing phosphorylation and activation of downstream targets involved in cell growth and survival. Pharmacologically relevant effects : In development for solid tumors such as prostate and breast cancers. Adverse effects : Hyperglycemia, rash, diarrhea, nausea, fatigue. IPATASERTIB MOA: Inhibits AKT, reducing phosphorylation of downstream substrates such as mTOR, limiting cell proliferation . Pharmacologically relevant effects: Used for prostate cancer in combination therapies. Adverse effects : Diarrhea, rash, nausea, fatigue, hyperglycemia .

19. PI3K/AKT/mTOR Pathway Inhibitors cont : mTOR Inhibitors ( Rapalogs ) 1.Everolimus ( Afinitor ) MOA : Inhibits mTORC1, reducing cell proliferation and angiogenesis. Pharmacologically relevant effects : Used for advanced kidney cancer, breast cancer, and neuroendocrine tumors. Adverse effects : Stomatitis, fatigue, hyperglycemia, dyslipidemia, pneumonitis, infections.

20. PI3K/AKT/mTOR Pathway Inhibitors cont : mTOR Inhibitors ( Rapalogs ) 2.Temsirolimus ( Torisel ) MOA : Prodrug of sirolimus, inhibits mTORC1 to block protein synthesis and cell growth. Pharmacologically relevant effects : Used for advanced renal cell carcinoma. Adverse effects : Rash, stomatitis, fatigue, hyperglycemia, hyperlipidemia, infections.

21. PI3K/AKT/mTOR Pathway Inhibitors cont : mTOR Inhibitors ( Rapalogs ) 3.Rapamycin (Sirolimus) MOA : Binds to FKBP12, inhibiting mTORC1, blocking protein synthesis and cell proliferation. Pharmacologically relevant effects : Used mainly as an immunosuppressant in organ transplantation. Adverse effects : Mouth ulcers, infections, hyperlipidemia, thrombocytopenia, increased cancer risk.

22. PI3K/AKT/mTOR Pathway Inhibitors: Dual mTORC1/mTORC2 Inhibitors 1.Torin1 MOA : Inhibits both mTORC1 and mTORC2, suppressing cell growth, proliferation, and survival signaling. Pharmacologically relevant effects : Preclinical research drug for cancer therapy. Adverse effects : Hyperglycemia, gastrointestinal toxicity, potential for immune suppression. 2.AZD8055 MOA : Potent ATP-competitive inhibitor of mTORC1 and mTORC2, blocking cell growth and survival. Pharmacologically relevant effects : In clinical trials for solid tumors. Adverse effects : Gastrointestinal toxicity, hyperglycemia, liver dysfunction.

23. MAPK/ERK Pathway Inhibitors 1.RAS Inhibitors 2.Sotorasib (AMG510) MOA : Irreversibly binds to and inhibits mutant KRAS G12C, blocking downstream signaling and tumor growth. Pharmacologically relevant effects : Approved for non-small cell lung cancer (NSCLC) with KRAS G12C mutations. Adverse effects : Diarrhea, hepatotoxicity, fatigue, nausea, cough.

24. MAPK/ERK Pathway Inhibitors: RAS Inhibitors Adagrasib (MRTX849) MOA : Selective inhibitor of KRAS G12C, binding to the inactive GDP-bound state of KRAS. Pharmacologically relevant effects : In clinical trials for NSCLC and other cancers. Adverse effects : Diarrhea, nausea, fatigue, hepatotoxicity.

25. MAPK/ERK Pathway Inhibitors: RAS Inhibitors b. Rigosertib MOA : Targets downstream RAS effector proteins, blocking RAS-mediated signaling in malignant cells. Pharmacologically relevant effects : Used in myelodysplastic syndromes. Adverse effects : Diarrhea, fatigue, nausea, urinary tract infections.

26. 2.MAPK/ERK Pathway Inhibitors: RAF Inhibitors c.Vemurafenib ( Zelboraf ) MOA: Selectively inhibits mutant BRAF V600E, preventing activation of downstream MEK and ERK signaling. Pharmacologically relevant effects: Used for BRAF V600E mutation-positive melanoma. Adverse effects : Arthralgia, rash, photosensitivity, QT prolongation, skin lesions.

27. REFERENCES YAN-JUN GUO, WEI-WEI PAN, SHENG-BENG LIU, ZHONG-FEI SHEN, YING XU AND LING-LING HU, epk / mapk signalling pathway and tumorigensis (review), doi : 10.389/etm.2020.8454, december,2019. YAN PENG, YUANYUAN WANG, CHENG ZHUO, WUXUAN MEI AND CHANGCHUN ZENG, PI3K/AKT/MTOR pathwya and its role in cancer therapeutics are we making headway?, 24 march 2022, doi : 10.3389/fonc.2022.819128. Zheng Y, Jiang Y. mTOR Inhibitors at a Glance. Mol Cell Pharmacol . 2015;7(2):15-20. PMID: 27134695; PMCID: PMC4849280. Martorana F, Motta G, Pavone G, Motta L, Stella S, Vitale SR, Mandela L, Vigneri P. AKT Inhibitors: New Weapons in the Fight Against Breast Cancer? Front Pharmacol . 2021 Apr 29;12:662232. doi : 10.3389/fphar.2021.662232. PMID: 33995085; PMCID: PMC8118639 https://cancercommons.org/latest-insights/mapk-pathway-in-cancer-new-treatments/