Regorafenib induces damage-associated molecular patterns, cancer cell death and immune modulatory effects in a murine triple negative breast cancer model

Optimization of Immunotherapy Strategies Based on Spatiotemporal Heterogeneity of Tumour-Associated Tissue-Resident Memory T Cells

Tissue-resident memory T cells (TRMs) reside in peripheral tissues and provide rapid immune defence against local infection and tumours. Tumour-associated TRMs share common tissue-resident features and formation mechanisms, representing some unique subsets of tumour-infiltrating lymphocytes (TILs). However, differences in the tumour microenvironment(TME) and tumour evolution stage result in TRMs exhibiting temporal and spatial heterogeneity of phenotype and function not only at different stages, before and after treatment, but also between tumours originating from different tissues, primary and metastatic cancer, and tumour and adjacent normal tissue. The infiltration of TRMs is often associated with immunotherapy response and favourable prognosis; however, due to different definitions, it has been shown that some subtypes of TRMs can also have a negative impact. Therefore, it is crucial to precisely characterise the TRM subpopulations that can influence the therapeutic efficacy and clinical prognosis of various solid tumours. Here, we review the spatiotemporal heterogeneity of tumour-associated TRMs, as well as the differences in their impact on clinical outcomes. We also explore the relationship between TRMs and immune checkpoint blockade (ICB) and TIL therapy, providing insights into potential new targets and strategies for immunotherapy.

Regorafenib induces DNA damage and enhances PARP inhibitor efficacy in pancreatic ductal carcinoma

BACKGROUND

There is increasing interest in enhancing the response of the PARP inhibitor olaparib, which is currently approved for pancreatic ductal adenocarcinoma (PDAC) patients with defects in DNA damage repair associated with germline BRCA1/2 mutations. Moreover, agents that can mimic these defects in the absence of germline BRCA1/2 mutations are an area of active research in hopes of increasing the number of patients eligible for treatment with PARP inhibitors. The extent to which regorafenib, an FDA-approved tyrosine kinase inhibitor, can be used to enhance the efficacy of PARP inhibitors in PDAC cells without known BRCA1/2 mutations remains to be investigated.

METHODS

Comet assay, cell cycle analysis, western blotting, and immunofluorescent detection of H2AXS139 were used to evaluate the extent to which regorafenib induces DNA damage in PDAC cell lines. The effects of regorafenib, either alone or in combination with PARPi inhibitors, on PDAC cell death were assessed by Annexin V/PI co-staining assay in cell lines and by immunohistochemistry staining for cleaved caspase-3 in mouse tumors and in ex vivo slice cultures of human PDAC tumors. Flow cytometry-based analysis was used to evaluate the ability of regorafenib to reprogram PDAC tumor microenvironment.

RESULTS

We now show that regorafenib, a tyrosine-kinase inhibitor with efficacy in several gastrointestinal malignancies, can enhance the response of olaparib in pancreatic cancer. While regorafenib induces DNA damage and limits the ability of PDAC cells to resolve the damage, regorafenib by itself does not induce apoptosis. However, regorafenib in combination with olaparib further induces DNA damage in vitro, in tumor-bearing mice, and in ex vivo slice cultures of human PDAC tumors, resulting in increased apoptosis compared to olaparib alone. Notably, we show that the efficacy of the combination treatment is not dependent on cytolytic T cells.

CONCLUSIONS

Together, these findings demonstrate that regorafenib can attenuate DNA damage response and potentiate the efficacy of PARP inhibitors in PDAC tumors.

Engineering nanomedicines for immunogenic eradication of cancer cells: Recent trends and synergistic approaches

Resistance to cancer immunotherapy is mainly attributed to poor tumor immunogenicity as well as the immunosuppressive tumor microenvironment (TME) leading to failure of immune response. Numerous therapeutic strategies including chemotherapy, radiotherapy, photodynamic, photothermal, magnetic, chemodynamic, sonodynamic and oncolytic therapy, have been developed to induce immunogenic cell death (ICD) of cancer cells and thereby elicit immunogenicity and boost the antitumor immune response. However, many challenges hamper the clinical application of ICD inducers resulting in modest immunogenic response. Here, we outline the current state of using nanomedicines for boosting ICD of cancer cells. Moreover, synergistic approaches used in combination with ICD inducing nanomedicines for remodeling the TME via targeting immune checkpoints, phagocytosis, macrophage polarization, tumor hypoxia, autophagy and stromal modulation to enhance immunogenicity of dying cancer cells were analyzed. We further highlight the emerging trends of using nanomaterials for triggering amplified ICD-mediated antitumor immune responses. Endoplasmic reticulum localized ICD, focused ultrasound hyperthermia, cell membrane camouflaged nanomedicines, amplified reactive oxygen species (ROS) generation, metallo-immunotherapy, ion modulators and engineered bacteria are among the most innovative approaches. Various challenges, merits and demerits of ICD inducer nanomedicines were also discussed with shedding light on the future role of this technology in improving the outcomes of cancer immunotherapy.

Potentials and future perspectives of multi-target drugs in cancer treatment: the next generation anti-cancer agents

Cancer is a major public health problem worldwide with more than an estimated 19.3 million new cases in 2020. The occurrence rises dramatically with age, and the overall risk accumulation is combined with the tendency for cellular repair mechanisms to be less effective in older individuals. Conventional cancer treatments, such as radiotherapy, surgery, and chemotherapy, have been used for decades to combat cancer. However, the emergence of novel fields of cancer research has led to the exploration of innovative treatment approaches focused on immunotherapy, epigenetic therapy, targeted therapy, multi-omics, and also multi-target therapy. The hypothesis was based on that drugs designed to act against individual targets cannot usually battle multigenic diseases like cancer. Multi-target therapies, either in combination or sequential order, have been recommended to combat acquired and intrinsic resistance to anti-cancer treatments. Several studies focused on multi-targeting treatments due to their advantages include; overcoming clonal heterogeneity, lower risk of multi-drug resistance (MDR), decreased drug toxicity, and thereby lower side effects. In this study, we'll discuss about multi-target drugs, their benefits in improving cancer treatments, and recent advances in the field of multi-targeted drugs. Also, we will study the research that performed clinical trials using multi-target therapeutic agents for cancer treatment.

HMGB1 in the interplay between autophagy and apoptosis in cancer

Lysosome-mediated autophagy and caspase-dependent apoptosis are dynamic processes that maintain cellular homeostasis, ensuring cell health and functionality. The intricate interplay and reciprocal regulation between autophagy and apoptosis are implicated in various human diseases, including cancer. High-mobility group box 1 (HMGB1), a nonhistone chromosomal protein, plays a pivotal role in coordinating autophagy and apoptosis levels during tumor initiation, progression, and therapy. The regulation of autophagy machinery and the apoptosis pathway by HMGB1 is influenced by various factors, including the protein's subcellular localization, oxidative state, and interactions with binding partners. In this narrative review, we provide a comprehensive overview of the structure and function of HMGB1, with a specific focus on the interplay between autophagic degradation and apoptotic death in tumorigenesis and cancer therapy. Gaining a comprehensive understanding of the significance of HMGB1 as a biomarker and its potential as a therapeutic target in tumor diseases is crucial for advancing our knowledge of cell survival and cell death.