Abstract Small molecules that induce non-apoptotic cell death are of fundamental mechanistic interest and may be useful to treat certain cancers. Here, we report that tegavivint, a drug candidate undergoing human clinical trials, can activate a unique mechanism of non-apoptotic cell death in sarcomas and other cancer cells. This lethal mechanism is distinct from ferroptosis, necroptosis and pyroptosis and requires the lipid metabolic enzyme trans-2,3-enoyl-CoA reductase (TECR). TECR is canonically involved in the synthesis of very long chain fatty acids but appears to promote non-apoptotic cell death in response to CIL56 and tegavivint via the synthesis of the saturated long-chain fatty acid palmitate. These findings outline a lipid-dependent non-apoptotic cell death mechanism that can be induced by a drug candidate currently being tested in humans.

Despite suppressive antiretroviral therapy (ART), HIV-1 persists in latent reservoirs that seed new HIV infections if ART is interrupted, necessitating lifelong therapy for people with HIV. Activation of latent HIV during ART could improve recognition and elimination of infected cells by the immune system. Protein kinase C (PKC) isozymes increase HIV transcription and hence are potential latency reversal agents. However, the clinical utility of PKCs for this application is limited due to toxicity, which is poorly understood. Our studies showed that PKC activation with multiple classes of agonists leads to widespread platelet activation, consistent with disseminated intravascular coagulation, at concentrations that were similar to those required for T-cell activation. Differential expression analysis indicated that PKC-ε and PKC-η isoforms are expressed at high levels in human CD4+ T cells but not in platelets. Using structure-based drug design, we developed a novel PKC agonist, C-233, with increased selectivity for PKC-ε. C-233 increased both supernatant HIV RNA and p24 expression ex vivo after treatment of CD4+ T cells from ART-suppressed people with HIV. C-233 was 5-fold more potent for T-cell activation relative to platelet activation. Our studies support the use of structure-based drug design to create selective novel PKC agonists for the safe activation of HIV reservoirs and improved tolerability.
Copyright: © 2025 Irrinki et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.

NKG2D ligands (NKG2DLs) are broadly expressed in cancer. To target these, we describe an adaptor chimeric antigen receptor (CAR) termed NKG2D/Dap10-12. Herein, T cells are engineered to co-express NKG2D with a fusion protein that comprises Dap10 joined to a Dap12 endodomain. NKG2D/Dap10-12 T cells elicit compelling efficacy, eradicating or controlling NKG2DL-expressing tumors in several established xenograft models. Importantly, durable responses, long-term survival, and rejection of tumor re-challenge are reproducibly achieved. Efficacy is markedly superior to a clinical stage CAR analog, comprising an NKG2D-CD3ζ fusion. Structure-function analysis using an extended CAR panel demonstrates that potency is dependent on membrane proximity of signaling units, high NKG2D cell surface expression, adaptor structure, provision of exogenous Dap10, and inclusion of one rather than three immune tyrosine activation motifs per signaling unit. Potent therapeutic impact of NKG2D/Dap10-12 T cells is also underpinned by enhanced oxidative phosphorylation, reduced senescence, and transcriptomic re-programming for increased ribosomal biogenesis.
Copyright © 2024 The Author(s). Published by Elsevier Inc. All rights reserved.

The coronavirus disease 2019 (COVID-19) reportedly exacerbates cancer outcomes. However, how COVID-19 influences cancer prognosis and development remains poorly understood. Here, we investigated the effect of Severe Acute Respiratory Syndrome Corona Virus 2 (SARS-CoV-2), the etiological agent of COVID-19, on cellular cancer phenotypes the expression of cancer-related markers, and various proinflammatory cytokines. We infected prostate (22RV1) and colorectal (DLD-1) cancer cell lines, which express angiotensin-converting enzyme 2 (ACE2), with spike pseudovirus (sPV) and laboratory stocks of live SARS-CoV-2 viruses. After infection, we quantified changes in the cellular cancer phenotypes, the gene expression levels of some cancer markers, including Ki-67, BCL-2, VIM, MMP9, and VEGF, and proinflammatory cytokines. Phenotypic analysis was performed using MTT and wound healing assays, whereas gene expression analysis was carried out using real-time quantitative PCR (RT-qPCR). We show that SARS-CoV-2 infection impacts several key cellular pathways involved in cell growth, apoptosis, and migration, in prostate and colorectal cancer cells. Our results suggest that SARS-CoV-2 infection does influence various cancer cellular phenotypes and expression of molecular cancer markers and proinflammatory cytokines, albeit in a cell-type-specific manner. Our findings hint at the need for further studies and could have implications for evaluating the impact of other viruses on cancer progression.
© 2024. The Author(s).

Cancer immunotherapy approaches that elicit immune cell responses, including T and NK cells, have revolutionized the field of oncology. However, immunosuppressive mechanisms restrain immune cell activation within solid tumors so additional strategies to augment activity are required.
We identified the co-stimulatory receptor NKG2D as a target based on its expression on a large proportion of CD8+ tumor infiltrating lymphocytes (TILs) from breast cancer patient samples. Human and murine surrogate NKG2D co-stimulatory receptor-bispecifics (CRB) that bind NKG2D on NK and CD8+ T cells as well as HER2 on breast cancer cells (HER2-CRB) were developed as a proof of concept for targeting this signaling axis in vitro and in vivo.
HER2-CRB enhanced NK cell activation and cytokine production when co-cultured with HER2 expressing breast cancer cell lines. HER2-CRB when combined with a T cell-dependent-bispecific (TDB) antibody that synthetically activates T cells by crosslinking CD3 to HER2 (HER2-TDB), enhanced T cell cytotoxicity, cytokine production and in vivo antitumor activity. A mouse surrogate HER2-CRB (mHER2-CRB) improved in vivo efficacy of HER2-TDB and augmented NK as well as T cell activation, cytokine production and effector CD8+ T cell differentiation.
We demonstrate that targeting NKG2D with bispecific antibodies (BsAbs) is an effective approach to augment NK and CD8+ T cell antitumor immune responses. Given the large number of ongoing clinical trials leveraging NK and T cells for cancer immunotherapy, NKG2D-bispecifics have broad combinatorial potential.
© 2024. The Author(s).