Loss of Parkinson's susceptibility gene LRRK2 promotes carcinogen-induced lung tumorigenesis

Pathological links between neurodegenerative disease and cancer are emerging. LRRK2 overactivity contributes to Parkinson’s disease, whereas our previous analyses of public cancer patient data revealed that decreased LRRK2 expression is associated with lung adenocarcinoma (LUAD). The clinical and functional relevance of LRRK2 repression in LUAD is unknown. Here, we investigated associations between LRRK2 expression and clinicopathological variables in LUAD patient data and asked whether LRRK2 knockout promotes murine lung tumorigenesis. In patients, reduced LRRK2 was significantly associated with ongoing smoking and worse survival, as well as signatures of less differentiated LUAD, altered surfactant metabolism and immunosuppression. We identified shared transcriptional signals between LRRK2-low LUAD and postnatal alveolarization in mice, suggesting aberrant activation of a developmental program of alveolar growth and differentiation in these tumors. In a carcinogen-induced murine lung cancer model, multiplex IHC confirmed that LRRK2 was expressed in alveolar type II (AT2) cells, a main LUAD cell-of-origin, while its loss perturbed AT2 cell morphology. LRRK2 knockout in this model significantly increased tumor initiation and size, demonstrating that loss of LRRK2, a key Parkinson’s gene, promotes lung tumorigenesis.

[SEPARATE ASPECTS OF LEGAL RESPONSIBILITY OF MEDICAL WORKERS ON THE EXAMPLE OF UKRAINE, GERMANY, FRANCE, THE USA]

The purpose of the study is to determine and analyze the features of the legal responsibility of medical workers for non-fulfillment or improper fulfillment of their professional duties. General scientific and special methods were used. The logical method of convergence from simple to complex made it possible to determine the main features of the legal responsibility of medical workers in the context of the analysis of the essence of medical activity and legal responsibility. The systemic-structural method made it possible to determine the place of civil responsibility of medical workers in Germany, France, the United States among other types of legal responsibility. Logical-legal and formal-legal methods made it possible to formulate the concepts "legal responsibility of medical workers as an institution of objective law" and "legal responsibility as an element of legal relations." The comparative legal method was used in the analysis of the legislation of foreign countries and Ukraine. We have established that a medical workers are special subjects and are held legally responsibility for failure to perform or improper performance of their professional duties, which are directly related to the nature of their work. A medical professional can potentially be brought to legal responsibility from the moment he begins to engage in his medical activity. The reality of the fact of bringing a medical professional to legal responsibility depends on the availability of the necessary grounds for its occurrence. The grounds for bringing a medical worker to legal responsibility are: the fact of committing a deliberate crime or an unjustified medical error; negative consequences for the life and health of the patient; a causal relationship between the fact of a deliberate crime or unjustified medical error and negative consequences for the patient. The main types of legal liability of medical workers include: criminal law, administrative law, civil law, disciplinary. The relationship between a patient and medical professionals in the USA, France, Germany is private, and is referred to as private law. These relations are mainly governed by the norms of civil law. In this regard, responsibility for "culpable defects" in the provision of medical services by medical workers is reduced to compensation for material and moral harm to the patient. Ukraine needs to develop and carry out a set of actions aimed at ensuring the protection of human rights, life and health in the medical field.

Diverse mechanisms of autophagy dysregulation and their therapeutic implications: does the shoe fit?

In its third edition, the Vancouver Autophagy Symposium presented a platform for vibrant discussion on the differential roles of macroautophagy/autophagy in disease. This one-day symposium was held at the BC Cancer Research Centre in Vancouver, BC, bringing together experts in cell biology, protein biochemistry and medicinal chemistry across several different disease models and model organisms. The Vancouver Autophagy Symposium featured 2 keynote speakers that are well known for their seminal contributions to autophagy research, Dr. David Rubinsztein (Cambridge Institute for Medical Research) and Dr. Kay F. Macleod (University of Chicago). Key discussions included the context-dependent roles and mechanisms of dysregulation of autophagy in diseases and the corresponding need to consider context-dependent autophagy modulation strategies. Additional highlights included the differential roles of bulk autophagy versus selective autophagy, novel autophagy regulators, and emerging chemical tools to study autophagy inhibition. Interdisciplinary discussions focused on addressing questions such as which stage of disease to target, which type of autophagy to target and which component to target for autophagy modulation. Abbreviations: AD: Alzheimer disease; AMFR/Gp78: autocrine motility factor receptor; CCCP: carbonyl cyanide m-chlorophenylhydrazone; CML: chronic myeloid leukemia; CVB3: coxsackievirus B3; DRPLA: dentatorubral-pallidoluysian atrophy; ER: endoplasmic reticulum; ERAD: ER-associated degradation; FA: focal adhesion; HCQ: hydroxychloroquine; HD: Huntingtin disease; HIF1A/Hif1α: hypoxia inducible factor 1 subunit alpha; HTT: huntingtin; IM: imatinib mesylate; MAP1LC3B: microtubule associated protein 1 light chain 3 beta; NBR1: neighbour of BRCA1; OGA: O-GlcNAcase; PDAC: pancreatic ductal adenocarcinoma; PLEKHM1: pleckstrin homology and RUN domain containing M1; polyQ: poly-glutamine; ROS: reactive oxygen species; RP: retinitis pigmentosa; SNAP29: synaptosome associated protein 29; SPCA3: spinocerebellar ataxia type 3; TNBC: triple-negative breast cancer.

A new quinoline-based chemical probe inhibits the autophagy-related cysteine protease ATG4B

The cysteine protease ATG4B is a key component of the autophagy machinery, acting to proteolytically prime and recycle its substrate MAP1LC3B. The roles of ATG4B in cancer and other diseases appear to be context dependent but are still not well understood. To help further explore ATG4B functions and potential therapeutic applications, we employed a chemical biology approach to identify ATG4B inhibitors. Here, we describe the discovery of 4-28, a styrylquinoline identified by a combined computational modeling, in silico screening, high content cell-based screening and biochemical assay approach. A structure-activity relationship study led to the development of a more stable and potent compound LV-320. We demonstrated that LV-320 inhibits ATG4B enzymatic activity, blocks autophagic flux in cells, and is stable, non-toxic and active in vivo. These findings suggest that LV-320 will serve as a relevant chemical tool to study the various roles of ATG4B in cancer and other contexts.

Clinical Applications of Autophagy Proteins in Cancer: From Potential Targets to Biomarkers

Autophagy, a lysosome-mediated intracellular degradation and recycling pathway, plays multiple context-dependent roles in tumorigenesis and treatment resistance. Encouraging results from various preclinical studies have led to the initiation of numerous clinical trials with the intention of targeting autophagy in various cancers. Accumulating knowledge of the particular mechanisms and players involved in different steps of autophagy regulation led to the ongoing discovery of small molecule inhibitors designed to disrupt this highly orchestrated process. However, the development of validated autophagy-related biomarkers, essential for rational selection of patients entering clinical trials involving autophagy inhibitors, is lagging behind. One possible source of biomarkers for this purpose is the autophagy machinery itself. In this review, we address the recent trends, challenges and advances in the assessment of the biomarker potential of clinically relevant autophagy proteins in human cancers.

Abstract 4722: Evaluation of the prognostic value of ATG4B expression in different breast cancer subtypes

Introduction: Autophagy, a lysosome-mediated degradation and recycling process, functions as an adaptive survival response during various stressful conditions including hypoxia and chemotherapy. The cysteine protease ATG4B, an important component of the autophagy pathway, is becoming a promising therapeutic target, but its value as a prognostic marker in breast cancer has not been investigated yet. Our recent studies established a novel association between ATG4B and HER2 positive breast cancer.

Objective: The aim of this study was to investigate the prognostic value of ATG4B in different breast cancer subtypes using a large population-based cohort.

Methods/Experimental Design: We evaluated ATG4B cytoplasmic expression by immunohistochemistry on tissue microarrays constructed from a cohort of 2003 breast cancer patients seen at the British Columbia Cancer Agency. For this large, well-characterized cohort detailed clinical information was available, including age, histology, tumor grade, tumor size, lymph node status, type of local and adjuvant systemic therapy, and dates of first recurrence and death. Median follow-up time was 12.4 years. ATG4B expression was scored by two independent observers using a categorized H-score system. Survival analyses were performed using the Kaplan-Meier function and Cox proportional hazards regression models to evaluate the association of ATG4B expression with breast cancer-specific survival, stratified by intrinsic subtype. Results: ATG4B expression was significantly lower in basal-like vs. non-basal (p<0.001), basal vs. HER2 overexpressed (p=0.0029), and triple-negative vs. non-triple-negative (p<0.001) breast cancer subtypes. In HER2 positive breast cancers, high (H-score >200) ATG4B expression was significantly associated with poor overall survival (hazard ratio (HR) =1.90, 95% confidence interval (CI) =1.10 to 3.27, p=0.033), disease specific survival (HR=2.23, CI =1.23 to 4.04, p=0.016), and relapse-free survival (HR=1.92, CI=1.09 to 3.39, p=0.037). However, in Luminal A breast cancers, high (H-score>150) ATG4B expression was strongly associated with improved overall survival (HR=0.71, CI=0.55 to 0.93, p=0.012) and disease-specific survival (HR=0.43, CI=0.26 to 0.67, p=0.00009).

Conclusion: High ATG4B expression is a poor prognostic marker in HER2 positive breast cancer, but a favorable prognostic factor in the Luminal A subtype. Validation analyses are planned on a further set of 1989 cases.

Citation Format: Svetlana Bortnik, Basile Tessier Cloutier, Jamie Magrill, Samuel Leung, Aline Talhouk, Karen Gelmon, Stephen Yip, Tony NG, Torsten Nielsen, Sharon Gorski. Evaluation of the prognostic value of ATG4B expression in different breast cancer subtypes [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 4722. doi:10.1158/1538-7445.AM2017-4722

Techniques for the Detection of Autophagy in Primary Mammalian Cells

Autophagy is a lysosomal catabolic pathway responsible for the degradation of cytoplasmic constituents. Autophagy is primarily a survival pathway for recycling cellular material in times of nutrient starvation, and in response to hypoxia, endoplasmic reticulum stress, and other stresses, regulated through the mammalian target of rapamycin pathway. The proteasomal pathway is responsible for degradation of proteins, whereas autophagy can degrade cytoplasmic material in bulk, including whole organelles such as mitochondria (mitophagy), bacteria (xenophagy), or lipids (lipophagy). Although signs of autophagy can be present during cell death, it remains controversial whether autophagy can execute cell death in vivo. Here, we will introduce protocols for detecting autophagy in mammalian primary cells by using western blots, immunofluorescence, immunohistochemistry, flow cytometry, and imaging flow cytometry.

Abstract 2902: The effectiveness of autophagy inhibition in sensitizing triple-negative breast cancer cells to chemotherapy

Introduction: High recurrence rates, drug resistance after initial response to chemotherapy, and overall poor prognosis along with the limited treatment options make triple-negative breast cancers (TNBCs) a major clinical challenge. Autophagy, an evolutionary conserved degradation and recycling process, has been shown to function as an adaptive survival response to chemotherapy. Previous studies have indicated higher expression of autophagy markers in TNBCs compared to other breast cancer subtypes, as well as their dependence on autophagy for survival. Our laboratory has also shown in xenograft models an enhanced effectiveness of chemotherapy for the treatment of TNBC when given in combination with autophagy inhibition (AI). These results support TNBCs as a good candidate for AI to improve efficacy of existing therapeutic regimens. However, currently available agents for AI in cancer patients have limited effectiveness, and development of more potent autophagy inhibitors (AIs) is underway.

Objective: Develop and test new tools for more potent AI in vivo.

Experimental Design: We are employing in vitro models using TNBC lines MDA-MB-231 and SUM159PT, as well as their derivatives R8 and R75, resistant to Epirubicin (EPI) and other anthracyclines. We are evaluating effects of various AIs, including lysosomotropic agents HCQ and lys05, siRNAs and shRNAs targeting autophagy-related (Atg) proteins, and small molecule inhibitors (under development) of ATG4B protein. In vivo xenograft mouse models of MDA-MB-231 and R8 are being used to evaluate the effects of combinatorial therapy with EPI and AI.

Methods: For the assessment of autophagy levels before and after AI we used autophagy flux (degradative completion of autophagy) assays. We evaluated the effects of chemotherapy alone and in combination with AIs on parent and resistant sub-lines by assessing their proliferation. For in vivo studies, TNBC cells are injected subcutaneously in Rag2M mice. Treatment with EPI, AI, or their combination is administered after tumor formation. Treatment efficacy is evaluated by tumor volume measurements; tumors are also assessed for the expression of autophagy markers.

Results: Our in vitro experiments showed enhanced cytotoxicity of lys05 compared to HCQ either alone or in combination with EPI. However, the use of lys05 in vivo gives contradictory results and requires further evaluation. AI targeting ATG4B, using shRNA-inducible monoclonal cell lines derived from MDA-MB-231 cells and novel small molecule inhibitors of ATG4B, significantly affected cancer cell proliferation in vitro, and is currently being investigated in vivo.

Conclusion: Novel approaches to AI may serve as useful tools to assess the effects of AI in vitro and in vivo. Our preliminary results suggest that more potent AIs may improve the effectiveness of treatment of TNBC.

Supported by CIHR GPG102167 and CIHR/AVON OBC127216.

Citation Format: Svetlana Bortnik, Suganthi Chittaranjan, Jing Xu, Wieslawa H. Dragowska, Jianghong An, Adrienne Kyle, Nancy E. Go, Lubomir Vezenkov, Courtney Choutka, Amy Leung, Suzana Kovacic, Damien Bosc, Karen Gelmon, Marcel Bally, Steven Jones, Robert Young, Sharon Gorski. The effectiveness of autophagy inhibition in sensitizing triple-negative breast cancer cells to chemotherapy. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 2902. doi:10.1158/1538-7445.AM2015-2902

Autophagy: from structure to metabolism to therapeutic regulation

Multidisciplinary approaches are increasingly being used to elucidate the role of autophagy in health and disease and to harness it for therapeutic purposes. The broad range of topics included in the program of the Vancouver Autophagy Symposium (VAS) 2013 illustrated this multidisciplinarity: structural biology of Atg proteins, mechanisms of selective autophagy, in silico drug design targeting ATG proteins, strategies for drug screening, autophagy-metabolism interplay, and therapeutic approaches to modulate autophagy. VAS 2013 took place at the British Columbia Cancer Research Centre, and was hosted by the CIHR Team in Investigating Autophagy Proteins as Molecular Targets for Cancer Treatment. The program was designed as a day of research exchanges, featuring two invited keynote speakers, internationally recognized for their groundbreaking contributions in autophagy, Dr Ana Maria Cuervo (Albert Einstein College of Medicine, Bronx, NY) and Dr Jayanta Debnath (University of California, San Francisco). By bringing together international and local experts in cell biology, drug discovery, and clinical translation, the symposium facilitated rich interdisciplinary discussions focused on multiple forms of autophagy and their regulation and modulation in the context of cancer.

Abstract 1684: Autophagy inhibition as an effective strategy for sensitizing triple-negative breast cancer cells to chemotherapy

Introduction: Triple-negative breast cancer (TNBC), defined by a lack of expression of the estrogen, progesterone and HER-2 receptors, remains a major clinical challenge due to higher recurrence rates and poorer prognosis compared to other subtypes of breast cancer. Tumors that initially respond to chemotherapy - the core treatment option for the patients with an advanced disease - eventually develop resistance. New therapeutic options are urgently required for TNBC. Autophagy, a lysosome-mediated degradation and recycling process, has been shown to function as an adaptive survival response during chemotherapy. Previous studies in other cancer subtypes have indicated that autophagy inhibition can restore chemotherapeutic sensitivity and enhance treatment response.

Objective: Generate proof-of-principle evidence for autophagy inhibition as an effective treatment strategy for TNBC.

Experimental Design: We are employing in vitro models using TNBC lines MDA-MB-231 and SUM159PT, as well as their derivative lines (R8 and R75, respectively) resistant to Epirubicin (EPI) and other anthracyclines. In vivo xenograft mouse models of MDA-MB-231 and R8 are being used to evaluate the effects of combinatorial therapy with EPI and autophagy inhibitor hydroxychloroquine (HCQ).

Methods: We assessed levels of autophagy in TNBC cell lines treated with EPI, developed EPI- resistant sub-lines, and compared basal autophagy levels in parental and resistant lines, using autophagy flux (degradative completion of autophagy) assays. We evaluated the effects of chemotherapy alone and in combination with autophagy inhibitors (HCQ or siRNAs targeting autophagy-related (Atg) proteins) on both parent and resistant sub-lines by assessing their viability. For in vivo studies, MDA-MB-231 cells were injected subcutaneously in Rag2M mice. After tumor formation, mice were treated with EPI, HCQ or their combination, and treatment efficacy was evaluated by tumor volume measurements. Autophagy levels in tumors were also assessed.

Results: TNBC cells demonstrated increased autophagy in response to EPI treatment in vitro and in vivo. EPI- resistant lines showed at least 1.5 fold increased basal autophagy levels compared to their parental lines suggesting a possible adaptive role for autophagy in development of chemoresistance. Knock-down of Atg proteins by siRNA dramatically reduced the viability of EPI-resistant sub-lines, which indicates dependence of drug-resistant cells on autophagy for survival. Resistance of MDA-MB-231-R8 cells to EPI was reverted by autophagy inhibition in vitro. Combination of EPI with HCQ in vivo showed an enhanced tumor response to treatment compared to monotherapy with EPI. Additional in vivo studies are in progress.

Conclusion: Our preliminary results suggest that autophagy inhibition may be an effective strategy for the treatment of chemo-refractory TNBC cells.

Citation Format: Svetlana Bortnik, Suganthi Chittaranjan, Wieslawa H. Dragowska, Namal Abeysundara, Amy Chen, Lindsay DeVorkin, Nancy Dos Santos, Nancy Erro Go, Amy Leung, Dana Masin, Maria Rizza, Dita Strutt, Sherry Weppler, Jing Xu, Hong Yan, Karen Gelmon, Donald Yapp, Marcel Bally, Sharon M. Gorski. Autophagy inhibition as an effective strategy for sensitizing triple-negative breast cancer cells to chemotherapy. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 1684. doi:10.1158/1538-7445.AM2013-1684