program cell death cell suicide extrinsic pathway intrinsic pathway various regulators proapoptotic antiapoptotic drugs tragedy regulators factor affecting p53 BCL2 cytochrome c positive regulators negative regulators

1. Apoptosis as a Target for Novel
Drugs(Proapoptotic & Antiapoptotic
Drugs)

2. Content:
Apoptosis significance
 Molecular mechanisms of apoptosis
signalling pathways
Regulatory mechanisms in apoptosis signal
Disease as a dysregulated of apoptosis
Apoptosis
• The significance of Apoptosis
• • Morphologicalfeatures of
• apoptosis
• • Molecularmechanisms of apoptosis
• signalling pathways.

3. Apoptosis
Specialized form of programmed cell death without an inflammatory response
 It is an active process regulated by proteins that often affects only single cells or
small groups of cells.
Mechanisms of Apoptosis
 Regulated by biochemical pathways that control balance of death- and
survival-inducing signals and ultimately activation of enzymes called caspases

6. Mechanisms of Apoptosis

7. Why should a cell commit suicide?
 Needed for proper normal development as mitosis
Examples - resorption of the tadpole tail in frog
 formation of fingers and toes of fetus
Removal by sloughing off of endometrium
 Cells infected with viruses
 Cells of immune system
 Cells with DNA damage
 Cancer cells (Uncontrolled proliferated cells)

8. Apoptosis: Role in Disease
Diseases of excess apoptosis: Tissue atrophy
Neurodegeneration
Parkinson's disease
Alzheimer's disease
Huntington's disease etc.
HIV myocardial infarction stroke
Thin skin
• Diseases of insufficient apoptosis: Hyperplasia
Cancer Autoimmunity

9. Regulators Ligand and
pharmacology approach

10. Positive regulators (proapoptotic)
P53
Fas CD95
Caspases
BAX BAK
BAD BID PUMA
Negative regulators (antiapoptotic )
Bcl2
Bcl-xl
Mcl-1

11. Targeting Death Receptors
TRAIL receptors CD95/Fas TNF
Major pathway of apoptosis is mediated by cellular death receptors belonging to
tumor necrosis factor (TNF) receptor superfamily
 Activation of a surface death receptor by its death ligand, TNF-a, CD95 ligand
(CD95L) or TNF-related apoptosis-inducing ligand (TRAIL) leads to intracellular
recruitment of death-inducing signaling complex (DISC) by means of protein/
protein interactions involving death domains
Atezolizumab-PDL-1(programmed death ligand ) for urothelial carcinoma non
small cell lung cancer
Avelumab-PDL-1 (programmed death ligand )merkel cell carcinoma
Basiliximab- CD95 for acute graft rejection
Nivolumab –malignant melanoma

12. BAX
Majority of BAX is found in cytosol
 Initiation of apoptotic signaling bax undergoes a conformational shift induction
of apoptosis
 BAX is membrane-associated and in particular mitochondrial membrane
associated
Expression of BAX is upregulated by tumor suppressor protein p53 and BAX has
been shown to be involved in p53-mediated apoptosis
Drugs that activate BAX such as ABT737
 BH3 mimetic as anticancer treatments by inducing apoptosis in cancer cells by
binding of HA-BAD to bcl-xl and disruption of bax:bcl-xl interaction was found to
partly reverse paclitaxel resistance in human ovarian cancer cells

13. Bad, Bid, Bim, Puma
 BH3-only proteins (Bad, Bid, Bim, Puma, and Noxa) sensors of cellular damage
and inactivate prosurvival Bcl-2 family
 Puma and Noxa are transcriptional targets of p53 and play a role in p53-
induced apoptosis Puma (p53 upregulated modulator of apoptosis)
Puma and Noxa are direct transcriptional targets of p53

14. TP53 (tumor suppressor gene p53)
 Critical tumour suppressor is mutated in ~50% of human cancers
 Activated in response to many stress stimuli, including activation of oncogenes
and DNA damage.
Combined loss of p53 effectors of apoptosis (puma plus noxa) and cell cycle
arrest/cell senescence (p21) does not cause spontaneous tumour development
 Fludarabine --purine analog currently applied in CLL patients and it removes CLL
cells by activating p53 and then downstream bh3-only family members,
consequent on the induction of DNA
Cyclophosphamide can kill tumor cells by causing DNA damaging by activation of
the intrinsic apoptosis pathway by tumor suppressor p53

16. Caspases -cysteine-aspartic proteases
• Caspase-1 caspase-3 caspase-6 caspase-9 FKBP12/
Roles of caspases such as cell proliferation, tumor suppression, cell
differentiation, neural deficiency
Caspase -3 can lead to excessive programmed cell death
 in several neurodegenerative diseases where neural cells are lost alzheimer
disease development and ageing
Caspase-1 causing autoimmune diseases
 A family of cysteine proteases, play a central role in apoptosis

17. IAPs and SMAC
Inhibitors of apoptosis proteins (IAP) human IAP family consists of 8 members
LCL161 -- drug that promotes cancer cell death by antagonizing IAPs and inhibits
caspase-3, -7 and -9
Survivin is an IAP member containing a single BIR domain, which is expressed to
high levels in cancer cells, but not in normal cells

18. Bcl-2 proteins
BCL-2 is a human proto-oncogene located on chromosome 18
Endoplasmic reticulum nuclear envelope and in outer membrane of
mitochondria
 Translocation is also found in some B-cell lymphoma as Damage to Bcl-2
gene identified as a cause of a number of cancers, including melanoma
breast prostate chronic lymphocytic leukemia and lung cancer
A possible cause of schizophrenia and autoimmunity
Venetoclax – antiapoptotic protein bcl2 inhibitor used for CLL

20. Gossypol
First compound that shows inhibition of bcl-2, bcl-xl and mcl-1
 Type of enantiomerism that arises from restricted rotation (−)gossypol isomer
shows greater cytotoxicity than (+)isomer in several human cancer cell
 gossypol and its analogs bind and interact with anti-apoptotic proteins bcl-2 and
bcl- XL, and induce cytochrome c release and bak activation in whole cells as well
as in isolated mitochondria that express high levels of bcl-2
 Further studies show that gossypol also induces bax/bak-independent activation
of apoptosis and cytochrome c release via a conformational change in bcl-2
Obatoclax mesylate (GX15-070), another drug targeting the bcl-2 family,
has also shown efficacy in phase III clinical trials

21. Histone deacetylase inhibitors
 HDAC -----new class of targeted anticancer agents that exert antitumor activity
by induce growth arrest and apoptosis
 Precise mechanism by hdac is induce apoptosis has not been clarified, but most
studies suggest on intrinsic pathway
 Recent studies show ----a rapid and extensive upregulation of noxa and bim
caused by HDAC is in CLL and other leukemic cells
HDAC inhibitors ---influence death receptors TRAIL (TNF related apoptosis
inducing ligand), DR5 (death receptor 5), fas, TNF (tumor necrosis factor) and
tnf-related ligands fas-l, LIGHT and TLA1 (transparent leaf area peptide)
Inhibition of those death receptors and their ligands inhibits apoptosis induced
by HDAC inhibitors

22. HDAC inhibitors and in different cancers to varying degrees.

24. Herbal Medicine as Inducers of Apoptosis in Cancer
Treatment
• Curcumin (Diferolelyl methane) phenol compound derived from rhizome of
curcuma specie increases response of tumor cells to doxorubicin through
blocking NF-Kβ signaling pathway
• Phase II clinical trial studies have shown curcumin is not toxic to human to a dose
of 8000 mg/day
• Ginger -phenol complex rhizome is used widely in traditional medicine Phenol
compounds of this plant show cytotoxic activity apoptosis in cancer cells
• Quercetin induces apoptosis by quercetin stimulated through release of
cytochrome-c to the cytosol and activating of caspase9

25. Referance
Targeting Oncogenic Mutant p53 for Cancer Therapy Alejandro Parrales1
Histone Deacetylase Inhibitors as Anticancer Drugs Tomas Eckschlager,1
BCL2 inhibitors as anticancer drugs: a plethora of misleading BH3 mimetics
Ryan S. Soderquist
Apoptosis-based therapies and drug targets U Fischer1 and K Schulze-Osthoff*,
Apoptosis: target for novel drugs John J. Alam
THE PHARMACOLOGICAL BASIS OF THERAPEUTICS
Robbins BASIC PATHOLOGY
• Herbal Medicine as Inducers of Apoptosis in Cancer Treatment Elham
Safarzadeh, Siamak Sandoghchian
• THIRTEENTH EDITION

26. THANKYOU