Mitochondrial-targeted brequinar liposome boosted mitochondrial-related ferroptosis for promoting checkpoint blockade immunotherapy in bladder cancer

Checkpoint blockade immunotherapy (CBI) have exhibited remarkable benefits for cancer therapy. However, the low responsivity of CBI hinders its application in treatment of bladder cancer. Ferroptosis shows potential for increasing the responsivity of CBI by inducing immunogenic cell death (ICD) process. Herein, we developed a mitochondrial-targeted liposome loaded with brequinar (BQR) (BQR@MLipo) for enhancing the mitochondrial-related ferroptosis in bladder cancer in situ. It could be found that BQR@MLipo could selectively accumulate into mitochondria and inactivate dihydroorotate dehydrogenase (DHODH), which induced extensive mitochondrial lipid peroxidation and ROS, finally triggering ferroptosis of bladder cancer cells to boost the release of intracellular damage-associated molecular patterns (DAMPs) such as calreticulin (CRT), adenosine triphosphate (ATP), high mobility group box 1 (HMGB1). In addition, BQR@MLipo further promoted the release of mtDNA into the cytoplasm to activate the cGAS-STING pathway for the secretion of IFN-β, which would increase the cross-presentation of antigens by dendritic cells and macrophage phagocytosis. Furthermore, the in vivo studies revealed that BQR@MLipo could remarkably accumulate into the bladder tumor and successfully initiate the infiltration of CD8+ T cells into tumor microenvironment for enabling efficient CBI to inhibit bladder tumor growth. Therefore, BQR@MLipo may represent a clinically promising modality for enhancing CBI in bladder tumor.

Dual antibody-aided mesoporous nanoreactor for H2O2 self-supplying chemodynamic therapy and checkpoint blockade immunotherapy in triple-negative breast cancer

Triple-negative breast cancer (TNBC) represents a formidable challenge due to the absence of estrogen receptor (ER), progesterone receptor (PR), and human epidermal growth factor receptor 2 (HER2) expression, rendering it unresponsive to conventional hormonal and targeted therapies. This study introduces the development of mesoporous nanoreactors (NRs), specifically mPDA@CuO2 NRs, as acid-triggered agents capable of self-supplying H2O2 for chemodynamic therapy (CDT). To enhance therapeutic efficacy, these NRs were further modified with immune checkpoint antagonists, specifically anti-PD-L1 and anti-CD24 antibodies, resulting in the formation of dual antibody-aided mesoporous nanoreactors (dAbPD-L1/CD24-mPDA@CuO2 NRs). These NRs were designed to combine CDT and checkpoint blockade immunotherapy (CBIT) for precise targeting of 4T1 TNBC cells. Remarkably, dAbPD-L1/CD24-mPDA@CuO2 NRs exhibited tumor-targeted CDT triggered by H2O2 and successfully activated immune cells including T cells and macrophages. This integrated approach led to a remarkable inhibition of tumor growth by leveraging the collaborative effects of the therapies. The findings of this study introduce a novel and promising strategy for the integrative and collaborative treatment of refractory cancers, providing valuable insights into addressing the challenges posed by aggressive breast cancer, particularly TNBC.

TRIM22 negatively regulates MHC-II expression

The development of cancer treatment has recently achieved a remarkable breakthrough, and checkpoint blockade immunotherapy has received much attention. To enhance the therapeutic efficacy of checkpoint blockade immunotherapy, recent studies have revealed the importance of activation of CD4⁺ T cells via an increase in major histocompatibility complex (MHC) class II molecules in cancer cells. Here, we demonstrate that tripartite motif-containing (TRIM) 22, negatively regulates MHC-II expression. Gene knockout of TRIM22 using Cas9-sgRNAs led to an increase of MHC-II proteins, while TRIM22 overexpression remarkably decreased MHC-II proteins. mRNA levels of MHC-II and class II transactivator (CIITA), which plays an essential role in the regulation of MHC-II transcription, were not affected by TRIM22. Furthermore, TRIM22 knockout did not suppress the degradation of MHC-II protein but rather promoted it. These results suggest that TRIM22 decreases MHC-II protein levels through a combination of multiple mechanisms other than transcription or degradation. We showed that inhibition of TRIM22 can increase the amount of MHC-II expression in cancer cells, suggesting a possibility of providing the biological basis for a possible therapeutic target to potentiate checkpoint blockade immunotherapy.

A novel human anti-TIGIT monoclonal antibody with excellent function in eliciting NK cell-mediated antitumor immunity

TIGIT is an emerging novel checkpoint target that is expressed on both tumor-infiltrating T cells and NK cells. Some current investigational antibodies targeting TIGIT have also achieved dramatic antitumor efficacy in late clinical research. Most recently, the relevance of NK cell-associated TIGIT signaling pathway to tumors' evasion of the immune system has been clearly revealed, which endows NK cells with a pivotal role in the therapeutic effects of TIGIT blockade. In this article, we describe a novel anti-TIGIT monoclonal antibody, AET2010, which was acquired from a phage-displayed human single-chain antibody library through a cell panning strategy. With emphasis on its regulation of NK cells, we confirmed the excellent ex vivo and in vivo antitumor immunity of AET2010 mediated by the NK-92MI cells. Intriguingly, our work also revealed that AET2010 displays a lower affinity but parallel avidity and activity relative to MK7684, an investigational monoclonal antibody from MSD, implying a reasonable balance of potency and potential side effects for AET2010. Together, these results are promising and warrant further development of AET2010.

Circulating biomarkers predictive of tumor response to cancer immunotherapy

Introduction: The advent of checkpoint blockade immunotherapy has revolutionized cancer treatment, but clinical response to immunotherapies is highly heterogeneous among individual patients and between cancer types. This represents a challenge to oncologists when choosing specific immunotherapies for personalized medicine. Thus, biomarkers that can predict tumor responsiveness to immunotherapies before and during treatment are invaluable. Areas covered: We review the latest advances in 'liquid biopsy' biomarkers for noninvasive prediction and in-treatment monitoring of tumor response to immunotherapy, focusing primarily on melanoma and non-small cell lung cancer. We concentrate on high-quality studies published within the last five years on checkpoint blockade immunotherapies, and highlight significant breakthroughs, identify key areas for improvement, and provide recommendations for how these diagnostic tools can be translated into clinical practice. Expert opinion: The first biomarkers proposed to predict tumor response to immunotherapy were based on PD1/PDL1 expression, but their predictive value is limited to specific cancers or patient populations. Recent advances in single-cell molecular profiling of circulating tumor cells and host cells using next-generation sequencing has dramatically expanded the pool of potentially useful predictive biomarkers. As immunotherapy moves toward personalized medicine, a composite panel of both genomic and proteomic biomarkers will have enormous utility in therapeutic decision-making.

The potentiated checkpoint blockade immunotherapy by ROS-responsive nanocarrier-mediated cascade chemo-photodynamic therapy

Checkpoint inhibitors, such as anti-PD-1/PD-L1 antibodies, have been proven as a promising type of immunotherapy in a number of cancers, but the relatively low response rates limit their scope of clinical application. Here, we report the use of cascade chemo-photodynamic therapy (chemo-PDT) with reactive oxygen species (ROS)-sensitive lipid-polymer hybrid nanoparticles ^TKHNP-C/D to potentiate the antitumor efficacy of anti-PD-L1 antibody (aPD-L1). Under light irradiation, ^TKHNP-C/D not only induced photodynamic therapy (PDT) but also boosted intracellular DOX release via the rapid degradation of its hydrophobic core, promoting an efficient cascade of chemo-PDT to inhibit tumor growth by a single treatment. More importantly, the cascade chemo-PDT could evoke anticancer immune responses and efficiently synergize with aPD-L1 to generate an abscopal effect, which could simultaneously inhibit primary and distant tumor growth.

Emerging predictors of the response to the blockade of immune checkpoints in cancer therapy

Checkpoint blockade-based immunotherapy offers new options and powerful weapons for the treatment of cancer, but its efficacy varies greatly among different types of cancer and across individual patients. Thus, the development of the right tools that can be used to identify patients who could benefit from this therapy is of utmost importance in order to maximize the therapeutic benefit, minimize risk of toxicities, and guide combination approaches. Multiple predictors have emerged that are based on checkpoint receptor ligand expression, tumor mutational burden, neoantigen and microsatellite instability, tumor-infiltrating immune cells, and peripheral blood biomarkers. In this review, we discuss the current state and progress of predictors as aids in checkpoint blockade-based immunotherapy in cancer.

The Role of Neoantigens in Naturally Occurring and Therapeutically Induced Immune Responses to Cancer

Definitive experimental evidence from mouse cancer models and strong correlative clinical data gave rise to the Cancer Immunoediting concept that explains the dual host-protective and tumor-promoting actions of immunity on developing cancers. Tumor-specific neoantigens can serve as targets of spontaneously arising adaptive immunity to cancer and thereby determine the ultimate fate of developing tumors. Tumor-specific neoantigens can also function as optimal targets of cancer immunotherapy against established tumors. These antigens are derived from nonsynonymous mutations that occur during cellular transformation and, because they are foreign to the host genome, are not subject to central tolerance. In this review, we summarize the experimental evidence indicating that cancer neoantigens are the source of both spontaneously occurring and therapeutically induced immune responses against cancer. We also review the advances in genomics, bioinformatics, and cancer immunotherapy that have facilitated identification of neoantigens and have moved personalized cancer immunotherapies into clinical trials, with the promise of providing more specific, safer, more effective, and perhaps even more generalizable treatments to cancer patients than current immunotherapies.