Molecular Revolution in Cancer Treatment. Linda H. Malkas, PhD

Transcription

1 Molecular Revolution in Cancer Treatment Linda H. Malkas, PhD

2 Nothing to disclose DISCLOSURE

3 Current Cancer Molecular Therapeutics It is a disease exhibiting heterogeneity making it difficult to treat successfully even with the most intensive multi-modal therapies available Identify tumor-associated characteristics for cancer selectivity defects in protein structure and interactions errors in cell signaling identify genome, transcriptome, and protein biomarkers that are relevant to cancer therapy and precision medicine search for- or improvement of - clinical agents that can selectively target tumors

4 Cancer: unmet need and a novel therapeutic strategy Newer inhibitory therapeutic strategies largely rely on the targeting of a single enzymatic activity in cancer cells, resulting in general good initial tumor response followed by the development of drug resistance A better approach to anticancer therapeutics would be targeting of key hub factors in molecular pathways critical for cancer cell growth and evolution such as DNA repair Targeting of molecular hubs would result in the shutting down of a myriad of functions in cancer cells and making it more difficult for these cells to develop resistant clones Targeting of molecular hubs in cancer cells could effectively lead to cancer cures

5 Why DNA Repair is Important

6 Eukaryotic DNA replication fork

7 Click to edit Master title style

8 Cancer Cell s DNA Replication Apparatus Is Altered in Function and Structure Human Cell DNA Synthesome MCF 10A MCF 7 Hs578Bst Hs578T MDA- MB468 PCNA Profile in Human Breast Tumor

9 PCNA IDCL Interactions Facilitate DNA Replication and Repair Protein-Protein Interaction Site Disordered Structure

10 Mapping the cancer associated domain

11 The L126-Y133 region is structurally altered and more exposed to protein-protein interaction in cancer-associated PCNA

12 Antibody Detects Caner Cells in Tissue Normal DCIS Invasive Metastatic

13 capcnaab Staining of Individual Slides

14 QUESTION Is capcna Expression Limited to Breast Cancer Cells?

15 Prostate Caner Tissues A: PCa; B: PCa + Adjacent Normal Epithelia; C: PCa; D: high grade Prostatic Intraepithelial Neoplasia Comparison of capcna staining in Adjacent Normal, high grade PIN, and PCa

16 Anti-caPCNA Pab-Fab2 staining of Cervical Cancer

17 Summary of Tissues Successfully Stained with the Rabbit Polyclonal Anti-caPCNA Antibody 1) Breast Cancer 2) Prostate Cancer 3) Ovarian Cancer 4) Esophageal Cancer 5) Neuroblastoma 6) Melanoma 7) Thyroid Cancer 8) Cervical Cancer 9) Colon Cancer 10) Glioblastoma 11) Pancreatic Cancer

18 Therapeutic Drug Discovery No-No Rules Drugs can only be made against proteins with enzymatic activities Drugs shouldn t be made against disordered regions in proteins Drugs can t be made to block protein-protein interactions

19 capcna Target Therapeutics Two Approaches Being Pursued - Peptide - Small molecules

20 Our Strategy + DNA damaging agent Damaged DNA PCNA + Repair Proteins Repaired DNA DNA damaging + Damaged DNA agent capcna Ca PEP + Repair Proteins Damaged DNA PCNA has many protein binding partners

21 How I See PCNA

22 What happened when you take a hub out?

23 Selective cytotoxicity of R9-caPep in NB cells

24 capep enhances the activity of cisplatin

25 Verifying capep sequence itself is cytotoxic to cancer cells

26 capep sequence inhibits NB tumor growth

27 capep inhibits DSB repair in cancer cells

28 Inhibition of DNA replication and induction of S-phase arrest and apoptosis by R9-caPep

29 R9-caPep interferes with replication fork extension

30 MYCN over-expression confers R9-caPep sensitivity

31 QUESTION Why does myc expression in neuroblastoma enhance sensitivity to capep?

32 MYCN amplification is associated with high Chk1 signaling and replication stress

33 High Chk1 expression is linked to poor prognosis

34 R9-caPep works synergistically with Chk1 inhibitors

35 Dysregulation of replication initiation and induction of DNA damage and apoptosis by R9-caPep and Chk1 inhibitors

36 capep action 1. Functional and structural basis: The L126-Y133 region of PCNA is functionally important and structurally altered in cancer cells. 2. Target validation: A cell permeable peptide harboring the L126-Y133 sequence selectively kill cancer cells, without causing significant toxicity to normal cells. ( 4 publications on 3 cancer types) 3. Druggability: The L126-Y133 region delineates a known small molecule binding pocket.

37 capeptide forms a cavity within capcna The Caldera

38 capep and its binding partners

39 Drug Discovery

40 AOH1996 in NCI-60 panel screen Median IC50=~320 nm

41 AOH1996 inhibits the growth of human neuroblastoma and small cell lung cancer cells

42 AOH1996 causes cell cycle arrest in cancer cells

43 Mechanism of action: Inhibition

44 Potential of AOH1996 in combination therapy of existing chemotherapeutic drugs

45 AOH small molecules have no thyroid hormone activity

46 Relative AOH1160 Concentrations Improved stability of AOH1996 in liver microsomes 1.2 Fig 4. Stability of AOH1160 in human Liver microsomes NADPH - NADPH Incubation time (min)

47 AOH1996 is stable to amide hydrolysis

48 AOH1996 is orally available to mice

49 Effect of AOH1996 on xenograft tumor growth in mice Vehicle AOH1996

50 14-Day Oral Toxicity Study of AOH1160 and AOH1996 in Mice Clinical and Anatomic Pathology Report CONCLUSIONS: The objective of this study was to determine the toxicity of AOH1996 in male and female Es1e/SCID mice following 14 days of oral, once daily administration. None of the observations in clinical pathology (hematology and clinical chemistry) parameters, macroscopic observations, or histopathology findings were considered a direct effect of the test article. The no-observed-adverse-effect level (NOAEL) for AOH1996 in this study was 100 mg/kg/day, the highest dose level tested.

51 Future Plans Complete IND-enabling preclinical studies and submit an IND application at end of year

52 T u m o r V o lu m e (c m 3 ) Targeting capcna for Cancer Treatment IMPACT Identified and validated a cancer-specific region (L126-Y133) of capcna as an anti-cancer drug target Developed an orally active small molecule compound (AOH1996), which targets this PCNA region and selectively kills cancer cells at sub-micromolar concentrations Virtual screen targeting the L126-Y133 region Vehicle only AOH D a y s a fte r tu m o r im p la n ta tio n Medicinal chemistry to improve potency and metabolic stability Malkas Funding Horne W81XWH-14-LCRP-CA Malkas W81XWH Hickey Reckamp Alex s Lemonade Stand Shared Resources APCF, DDSB, MMSBD Publications Gu et al. Plos One 2014 Gu et al. EBioMedicine 2014 Smith et al. Mol Pharmacology 2015 Start-Up Company Synold Chung Penetrates BBB and active against glioblastoma RLL, LLC FDA pre-ind package submitted and answered

53 Summary DNA repair is a critical pathway for cell survival and a good target for anticancer drug development (ex. PARP inhibitors) Identified and validated a cancer-specific region of PCNA as a therapeutic target Developed a potent small molecule compound (a snowstorm) that targets this PCNA region and selectively kills a broad-spectrum of cancer cells Protein-protein interaction sites and disordered protein domains can be used for drug targets Targeting important molecular hubs in cancer cells can be a viable drug development strategy

54 Shutting down hub to hub (or huba huba)

55

56 Acknowledgments City of Hope Dr. Robert Hickey Dr. Long Gu Dr. Shanna Smith Dr. Caroline Li Mr. Robert Lingeman Dr. David Horne Dr. John Williams Dr. Binghui Shen Dr. Yate-Ching Yuan Dr. Yun Yen Dr. Jeremy Stark Dr. Hua Yu Dr. Andreas Hermann St. Jude s Cancer Center Dr. John Sandoval TGen Dr. Daniel Von Hoff Greater Baltimore Center Dr. Lauren Schnaper University of Maryland Dr. Pamela Bechtel Dr. Jennifer Sekowski Indiana University Dr. Sunil Badve Dr. George Sandusky Dr. Beamon Argawal Dr. Jianying Liu Dr. George Sledge Dr. Fei Shen Ms. Lacey Dobrolechi Torrey Pines Institute Dr. Gregg Fields Albany Molecular Research, Inc. (AMR) University of Arizona Dr. Paul Myrdal

57 Thank you NIH/NCI DoD Research Group CDMRP Geyer Foundation Vera Bradley Foundation St. Baldrick s Foundation The ANNA Foundation Lung Cancer Research Foundation Alex s Lemonade Stand Foundation STOP CANCER Anna Olivia Healey AOH