Targeting Autophagy

Autophagy is regarded as the intracellular recycling machinery for degrading and reusing cytosolic materials. It acts as a node connecting many cellular events, therefore, targeting autophagy could eliminate the need to target multiple pathways. Autophagy has been shown to play a role in many diseases, such as cancer, autoimmune, CNS, metabolic and infectious disorders. However, targeting autophagy is complex because there are different types of autophagy and they all involve various cellular pathways that are not well understood. Many studies have shown that autophagy can also have a binary function, for instance, acting as a tumor suppressor or a tumor enhancer in cancer. Despite such complexities, it is promising to see many preclinical and clinical studies underway using already approved autophagy drugs and novel inhibitors. Cambridge Healthtech Institute’s symposium on Targeting Autophagy taps into the recent excitement in this field by bringing together a group of experts who are uncovering new mechanisms and inhibitors to help drug discovery. This symposium will be followed by a conference that focuses on targeting the ubiquitin-proteasome system and will draw on some of the synergies between these two areas of research.

Final Agenda

Tuesday, September 25

8:00 am Pre-Conference Symposia and Short Course Registration

8:00 Morning Coffee

UNDERSTANDING THE CELLULAR EFFECTS OF TARGETING AUTOPHAGY

9:00 Welcome Remarks

Tanuja Koppal, PhD, Conference Director, Cambridge Healthtech Institute

9:05 Chairperson’s Opening Remarks

Jeff MacKeigan, PhD, Professor of Cancer Biology and Complex Diseases, College of Human Medicine, Michigan State University

9:15 Autophagy in Cancer: Known and Unique Targets

Jeff MacKeigan, PhD, Professor of Cancer Biology and Complex Diseases, College of Human Medicine, Michigan State University

Our lab uses predictive computational modeling and cell-based measurements to accurately model the autophagic process. We are now extending our models to predict the therapeutic benefit of inhibiting autophagy in cancer. Our research suggests that targeting known and unique kinases in the autophagy pathway can uncover more selective and potent small molecule inhibitors as compared to current lysomotropic agents.

9:45 Downregulation of Autophagy by a Cancer-Specific Ubiquitin Ligase Targeting AMPK

Ryan Potts, PhD, Associate Member, Department of Cell and Molecular Biology, St. Jude Children’s Research Hospital

AMP-activated protein kinase (AMPK) is a master sensor and regulator of cellular energy status. Upon metabolic stress, AMPK suppresses anabolic and promotes catabolic processes, including autophagy, to regain energy homeostasis. Here, I will discuss a widespread mechanism to suppress AMPK through its ubiquitination and degradation by the cancer-specific MAGE-A3/6-TRIM28 ubiquitin ligase. Recent findings on the regulation of MAGE-A3/6 protein stability under nutrient deprivation will also be discussed.

10:15 Targeting Autophagy in Colorectal Cancer Cells: A Relevant Strategy?

Steve Jean, PhD, Assistant Professor, Department of Anatomy and Cell Biology, Université de Sherbrooke

APC loss, and KRAS activation, two hallmarks of CRC, are linked to increased autophagic flux, suggesting a potential involvement of autophagy in CRC. Through in vivo approaches on CRC cell lines, we found that the outcome of autophagy inhibition in a complex system is unpredictable. Hence, the relationship between autophagy inhibition and cancer driver/passenger mutations must be clarified before autophagy inhibition can be considered as a therapeutic avenue in CRC.

10:45 Sponsored Presentation (Opportunity Available)

11:00 Networking Coffee Break with Poster Viewing

11:30 Leveraging Autophagy’s Ability to Regulate Apoptosis to Improve Cancer Therapy

Andrew Thorburn, DPhil, Chair, Department of Pharmacology, University of Colorado, School of Medicine

In this presentation, I will discuss how autophagy inhibition sensitizes tumor cells to undergo apoptosis and necroptosis and how this can be leveraged to enhance the activity of other anti-cancer agents.

12:00 pm Regulation of Innate Immunity by Selective Autophagy

Aditya Murthy, PhD, Scientist, Cancer Immunology, Genentech, Inc.

Molecular mechanisms by which autophagy limits inflammation remain poorly understood. We have recently shown that loss of the autophagy gene Atg16L1 promotes interferon-mediated pathology via accumulation of the signaling adaptor TRIF. Multiplexed proteomics identified SQSTM1/p62 and Tax1BP1 as autophagy receptors for TRIF. Human macrophages harboring the Crohn’s disease-associated ATG16L1 variant (T300A) exhibited elevated cytokine production upon TLR3/4 stimulation. These findings implicate selective autophagy as a key immunoregulatory node in innate immunity.

12:30 Extrinsic Roles of Tumor-Intrinsic Autophagy

Christina H. Eng, PhD, Senior Principal Scientist, Pfizer Oncology R&D

The role of autophagy in cancer has been extensively examined, yet the impact of autophagy inhibition on neoplastic disease varies greatly and depends on a number of factors such as genetic context and tumor landscape. Metabolic stress such as nutrient and oxygen limitation, oncogenic mutations, and chemotherapeutic treatment are all situations that may fuel the dependence on autophagy in tumorigenic cells. Our findings indicate that autophagic activity in malignant cells does not promote tumorigenesis in a cancer-cell intrinsic manner, but alters extrinsic host responses to tumor growth.

1:00 Sponsored Presentation (Opportunity Available)

1:00 Pre-Conference Short Course Registration

1:15 Enjoy Lunch on Your Own

Exploring Tools & Assays To Probe And Quantify The Autophagy Cascade

2:45 Chairperson’s Remarks

Ian Ganley, PhD, Programme Leader, The MRC Protein Phosphorylation and Ubiquitylation Unit, The Sir James Black Centre, School of Life Sciences, University of Dundee

2:55 Illuminating Mitochondrial Autophagy in Vivo

Ian Ganley, PhD, Programme Leader, The MRC Protein Phosphorylation and Ubiquitylation Unit, The Sir James Black Centre, School of Life Sciences, University of Dundee

Mitophagy, the autophagy of mitochondria, is an essential quality control (QC) mechanism of pathophysiological relevance with strong links to Parkinson’s disease, cancer and inflammatory disorders. However, if and how mitophagy proceeds within specific cellular subtypes in vivo has remained unclear, largely due to a lack of tractable models. To address this, we developed “mito-QC”, a fluorescent reporter mouse that allows the facile assessment of mitophagy and mitochondrial architecture in vivo.

3:25 Phenotypic Screening Paradigms for Autophagy Pathway Regulators

Philip A. Bergman, BS, Investigator III, Chemical Biology and Therapeutics, Novartis Institutes for BioMedical Research, Inc.

To identify novel autophagy pathway nodes, we established phenotypic pooled CRISPR screening paradigms and mapped regulators of autophagy cargo and cargo receptors in mammalian cells. As proof of concept, we performed a genome-wide screen for the autophagy cargo receptor p62 and validated mTOR signaling and the entire macroautophagy machinery as key regulators of p62 turnover. Here, we will present our progress in applying phenotypic screening paradigms to identify novel autophagy pathway nodes.

GOING BEYOND AUTOPHAGY

3:55 Regulation and Consequences of Autophagy and Non-Canonical Autophagy Resembling LC3-Associated Phagocytosis or LAP

Michael Overholtzer, PhD, Associate Member, Cell Biology Program, Memorial Sloan Kettering Cancer Center

Autophagy proteins have parallel functions in non-autophagic processes that involve LC3 lipidation. Notably, LC3-Associated Phagocytosis or LAP was discovered as a parallel function of core autophagy proteins that lipidate LC3 onto phagosomes and other endocytic membranes. Here I will discuss new data uncovering regulation of LAP and the consequences of this process that differ from macroautophagy. The engagement of LAP by lysosomotropic drugs, including chloroquine, will also be discussed.

4:25 Roles for Autophagy Genes beyond Autophagy: Control of Exosome Release and Exosome-Mediated Metastasis

Derrick Gibbings, PhD, Assistant Professor, Cellular and Molecular Medicine, University of Ottawa

Autophagy and autophagy-related genes (Atg) have been attributed prominent roles in tumorigenesis, tumor growth, and metastasis. Extracellular vesicles called exosomes are also implicated in cancer metastasis. Here, we demonstrate that exosome production is strongly reduced in cells lacking Atg5 and Atg16L1, but this is independent of Atg7 and canonical autophagy. These findings uncover mechanisms controlling exosome release and identify means by which autophagy-related genes can contribute to metastasis in autophagy-independent pathways.

4:55 Closing Comments

Tanuja Koppal, PhD, Conference Director, Cambridge Healthtech Institute

5:00 Close of Symposium

5:00 Pre-Conference Dinner Short Course Registration