Loss of GABARAP mediates resistance to immunogenic chemotherapy in multiple myeloma.

ABSTRACT: Immunogenic cell death (ICD) is a form of cell death by which cancer treatments can induce a clinically relevant antitumor immune response in a broad range of cancers. In multiple myeloma (MM), the proteasome inhibitor bortezomib is an ICD inducer and creates durable therapeutic responses in patients. However, eventual relapse and resistance to bortezomib appear inevitable. Here, by integrating patient transcriptomic data with an analysis of calreticulin (CRT) protein interactors, we found that GABA type A receptor-associated protein (GABARAP) is a key player whose loss prevented tumor cell death from being perceived as immunogenic after bortezomib treatment. GABARAP is located on chromosome 17p, which is commonly deleted in patients with high risk MM. GABARAP deletion impaired the exposure of the eat-me signal CRT on the surface of dying MM cells in vitro and in vivo, thus reducing tumor cell phagocytosis by dendritic cells and the subsequent antitumor T-cell response. Low GABARAP was independently associated with shorter survival in patients with MM and reduced tumor immune infiltration. Mechanistically, we found that GABARAP deletion blocked ICD signaling by decreasing autophagy and altering Golgi apparatus morphology, with consequent defects in the downstream vesicular transport of CRT. Conversely, upregulating autophagy using rapamycin restored Golgi morphology, CRT exposure, and ICD signaling in GABARAPKO cells undergoing bortezomib treatment. Therefore, coupling an ICD inducer, such as bortezomib, with an autophagy inducer, such as rapamycin, may improve patient outcomes in MM, in which low GABARAP in the form of del(17p) is common and leads to worse outcomes.

Education and electronic medical records and genomics network, challenges, and lessons learned from a large-scale clinical trial using polygenic risk scores.

Polygenic risk scores (PRS) have potential to improve health care by identifying individuals that have elevated risk for common complex conditions. Use of PRS in clinical practice, however, requires careful assessment of the needs and capabilities of patients, providers, and health care systems. The electronic Medical Records and Genomics (eMERGE) network is conducting a collaborative study which will return PRS to 25,000 pediatric and adult participants. All participants will receive a risk report, potentially classifying them as high risk (∼2-10% per condition) for 1 or more of 10 conditions based on PRS. The study population is enriched by participants from racial and ethnic minority populations, underserved populations, and populations who experience poorer medical outcomes. All 10 eMERGE clinical sites conducted focus groups, interviews, and/or surveys to understand educational needs among key stakeholders-participants, providers, and/or study staff. Together, these studies highlighted the need for tools that address the perceived benefit/value of PRS, types of education/support needed, accessibility, and PRS-related knowledge and understanding. Based on findings from these preliminary studies, the network harmonized training initiatives and formal/informal educational resources. This paper summarizes eMERGE's collective approach to assessing educational needs and developing educational approaches for primary stakeholders. It discusses challenges encountered and solutions provided.

DAMPening Tumor Immune Escape: The Role of Endoplasmic Reticulum Chaperones in Immunogenic Chemotherapy.

Significance: Preclinical and clinical research in the past two decades has redefined the mechanism of action of some chemotherapeutics that are able to activate the immune system against cancer when cell death is perceived by the immune cells. This immunogenic cell death (ICD) activates antigen-presenting cells (APCs) and T cells to induce immune-mediated tumor clearance. One of the key requirements to achieve this effect is the externalization of the damage-associated molecular patterns (DAMPs), molecules released or exposed by cancer cells during ICD that increase the visibility of the cancer cells by the immune system. Recent Advances: In this review, we focus on the role of calreticulin (CRT) and other endoplasmic reticulum (ER) chaperones, such as the heat-shock proteins (HSPs) and the protein disulfide isomerases (PDIs), as surface-exposed DAMPs. Once exposed on the cell membrane, these proteins shift their role from that of ER chaperone and regulator of Ca2+ and protein homeostasis to act as an immunogenic signal for APCs, driving dendritic cell (DC)-mediated phagocytosis and T-mediated antitumor response. Critical Issues: However, cancer cells exploit several mechanisms of resistance to immune attack, including subverting the exposure of ER chaperones on their surface to avoid immune recognition. Future Directions: Overcoming these mechanisms of resistance represents a potential therapeutic opportunity to improve cancer treatment effectiveness and patient outcomes.