Immunogenic hypofractionated radiotherapy sensitising head and neck squamous cell carcinoma to anti-PD-L1 therapy in MDSC-dependent manner.

BACKGROUND: Enhancing the response rate of immunotherapy will aid in the success of cancer treatment. Here, we aimed to explore the combined effect of immunogenic radiotherapy with anti-PD-L1 treatment in immunotherapy-resistant HNSCC mouse models. METHODS: The SCC7 and 4MOSC2 cell lines were irradiated in vitro. SCC7-bearing mice were treated with hypofractionated or single-dose radiotherapy followed by anti-PD-L1 therapy. The myeloid-derived suppressive cells (MDSCs) were depleted using an anti-Gr-1 antibody. Human samples were collected to evaluate the immune cell populations and ICD markers. RESULTS: Irradiation increased the release of immunogenic cell death (ICD) markers (calreticulin, HMGB1 and ATP) in SCC7 and 4MOSC2 in a dose-dependent manner. The supernatant from irradiated cells upregulated the expression of PD-L1 in MDSCs. Mice treated with hypofractionated but not single-dose radiotherapy were resistant to tumour rechallenge by triggering ICD, when combined with anti-PD-L1 treatment. The therapeutic efficacy of combination treatment partially relies on MDSCs. The high expression of ICD markers was associated with activation of adaptive immune responses and a positive prognosis in HNSCC patients. CONCLUSION: These results present a translatable method to substantially improve the antitumor immune response by combining PD-L1 blockade with immunogenic hypofractionated radiotherapy in HNSCC.

Bioengineering of BRAF and COX2 inhibitor nanogels to boost the immunotherapy of melanoma via pyroptosis.

Glutathione-responsive nanogels (CDNPs) crosslinked via crosslinker DBHD with the BRAF inhibitor dabrafenib and the COX2 inhibitor celecoxib were fabricated. The CDNPs can effectively induce tumor cell pyroptosis to activate robust antitumor immunity. Additionally, CDNPs combined with αPD-1 antibody greatly inhibited tumor growth in a melanoma mouse model with a prolonged survival time.

pH-responsive nanoprodrugs combining a Src inhibitor and chemotherapy to potentiate antitumor immunity via pyroptosis in head and neck cancer.

As the prominent feature of the development and progression of head and neck squamous cell carcinoma (HNSCC) is immunosuppression, therapeutic strategies to restore antitumor immunity have shown promising prospects. The efficacy of chemotherapy, a mainstay in HNSCC treatment, is exemplified by cytotoxic effects as well as immunostimulation, whereas compensatory activation of prosurvival signals in tumor tissues may compromise its efficacy. Aberrant activation of Src is present in many human malignancies including HNSCC, and is implicated in chemotherapy resistance. In this regard, tumor-microenvironment-responsive prodrug nanomicelles (PDO NPs) are rationally designed to combine chemotherapy (oxaliplatin, OXA) and Src inhibitors (dasatinib, DAS) for HNSCC therapy. PDO NPs are constructed by chemically modifying small-molecule prodrugs (DAS-OXA) loaded in block copolymer iPDPA with pH-triggered transforming capability. PDO NPs can controllably release drugs in response to tumor acidity, thus increasing tumor accumulation and therapeutic efficacy. Moreover, PDO NPs can elicit pyroptosis of tumor cells and induce T-cell-mediated antitumor immunity in murine HNSCC models. In summary, nanoprodrugs integrating Src inhibitors enhance the immunological effects of chemotherapy and provide insight into promising approaches for augmenting immunochemotherapy for HNSCC. STATEMENT OF SIGNIFICANCE: In this study, pH-responsive nanomicelles (PDO NPs) were constructed by loading a small molecular prodrug synthesized by the Src inhibitor dasatinib and the chemotherapy drug oxaliplatin into the amphiphilic block copolymer iPDPA to improve the immunological effects of chemotherapy for HNSCC. These nanomicelles can efficiently accumulate in tumor cells and achieve pH-responsive drug release. The PDO NPs can induce pyroptosis of tumor cells and potentiate antitumor immunity in subcutaneous and syngenetic orthotopic HNSCC mouse models, which may present a promising strategy to enhance immunochemotherapy for HNSCC.

Inhibition of DNMT1 potentiates antitumor immunity in oral squamous cell carcinoma.

Epigenetic alterations, including DNA methylation, play crucial roles in the tumor. Epigenetic drugs like DNA methyltransferase-1 (DNMT1) inhibitors have been exhibited positive effects in cancer treatment. However, the role of DNMT1 in oral squamous cell carcinoma (OSCC) is less clearly described. What is more, the effects on the immune microenvironment of DNMT1 have not become appreciated. In this research, we determine the expression levels of DNMT1 and the association of prognosis by analyzing human OSCC tissue microarrays. Two different types of immunocompetent mouse OSCC models were established to explore the effects of DNMT1 inhibitor on the tumor microenvironment(TME). We identified DNMT1 was highly expressed both in human and mouse OSCC tissues. The expression levels of DNMT1 was also correlated with the immunosuppressive molecules and tumor-promoter such as VISTA, PD-L1, B7-H4, and PAK2, indicating a worse prognosis. Of particular concern is that DNMT1 inhibition improved TME and delayed tumor growth by decreasing myeloid-derived suppressor cells (MDSCs) and increasing tumor-infiltrating T cells. Our data suggests that DNMT1 play a key role in OSCC and has a possible immunotherapeutic marker treatment.

Impacts of Mercury Exposure Levels and Sources on the Demethylation of Methylmercury Through Human Gut Microbiota.

This study aims to investigate methylmercury (MeHg) demethylation processes in human gut. Here, we determined the compositions and MeHg demethylation rates of gut microbiota in residents from different Hg exposure levels (Wanshan (WS) town and Yangtou (YT) town) and different Hg exposure sources (Zhuchang (ZC) town and YT town) regions. MeHg and inorganic Hg exposure levels in residents of WS town were significantly higher than those of YT and ZC town. Desulfovibrio and Methanogens, which related to Hg methylation/demethylation, showed significantly higher abundance in WS and ZC, comparing with YT. In vitro experiments demonstrated that human intestinal microbiota could degrade MeHg directly. Besides, gut microbiota in WS and ZC exhibited significantly higher demethylation rates than YT, suggesting Desulfovibrio and Methanogens may play important roles in intestinal MeHg demethylation. This study highlights Hg exposure levels and sources may affect demethylation efficiency of gut microbiota, which provides new insights for MeHg demethylation processes in human body.

Microenvironment-Responsive Prodrug-Induced Pyroptosis Boosts Cancer Immunotherapy.

The absence of tumor antigens leads to a low response rate, which represents a major challenge in immune checkpoint blockade (ICB) therapy. Pyroptosis, which releases tumor antigens and damage-associated molecular patterns (DAMPs) that induce antitumor immunity and boost ICB efficiency, potentially leads to injury when occurring in normal tissues. Therefore, a strategy and highly efficient agent to induce tumor-specific pyroptosis but reduce pyroptosis in normal tissues is urgently required. Here, a smart tumor microenvironmental reactive oxygen species (ROS)/glutathione (GSH) dual-responsive nano-prodrug (denoted as MCPP) with high paclitaxel (PTX) and photosensitizer purpurin 18 (P18) loading is rationally designed. The ROS/GSH dual-responsive system facilitates the nano-prodrug response to high ROS/GSH in the tumor microenvironment and achieves optimal drug release in tumors. ROS generated by P18 after laser irradiation achieves controlled release and induces tumor cell pyroptosis with PTX by chemo-photodynamic therapy. Pyroptotic tumor cells release DAMPs, thus initiating adaptive immunity, boosting ICB efficiency, achieving tumor regression, generating immunological memory, and preventing tumor recurrence. Mechanistically, chemo-photodynamic therapy and control-release PTX synergistically induce gasdermin E (GSDME)-related pyroptosis. It is speculated that inspired chemo-photodynamic therapy using the presented nano-prodrug strategy can be a smart strategy to trigger pyroptosis and augment ICB efficiency.

TIGIT/CD155 blockade enhances anti-PD-L1 therapy in head and neck squamous cell carcinoma by targeting myeloid-derived suppressor cells.

OBJECTIVES: Anti-PD-1/PD-L1 therapy has recently been approved for head and neck squamous cell carcinoma (HNSCC). However, given that large numbers of patients with HNSCC do not respond to PD-1/PD-L1 antibodies, combination strategies for elevating the response rate need to be further investigated. The goal of this study was to explore the possibility of dual-targeting CD155/TIGIT and PD-1/PD-L1 signalling in HNSCC. MATERIALS AND METHODS: Multiplex flow cytometry was performed to determine the co-expression of CD155 and PD-L1 in human HNSCC and transgenic HNSCC mouse models. The combined application of TIGIT mAb and PD-L1 mAb in a mouse model was used to explore the therapeutic effect. RESULTS: CD155 and PD-L1 were highly co-expressed on myeloid-derived suppressor cells (MDSCs) derived from patients with HNSCC and were inversely associated with the percentage of tumour CD3+ T and effector memory T cells. CD155+PD-L1+ MDSCs in the mouse model were gradually enriched in the tumour microenvironment in the middle and late stages of tumour progression. Anti-PD-L1 treatment alone upregulated the expression of CD155 on MDSCs and while anti-TIGIT treatment upregulated the expression of PD-L1 on MDSCs in mice. The combined blockade of TIGIT/CD155 and PD-1/PD-L1 signalling in mice significantly inhibited tumour growth, enhanced the percentages of effector T cells and cytokine secretion and elicited immune memory effects. CONCLUSION: Our study indicated that CD155+PD-L1+ MDSCs are enriched in the tumour microenvironment and blocking TIGIT/CD155 can effectively enhance the response rate of HNSCC to PD-L1 mAb therapy, which provides the clinical potential of co-targeting TIGIT/CD155 and PD-1/PD-L1 signalling.

Long Non-coding RNA LINC02195 as a Regulator of MHC I Molecules and Favorable Prognostic Marker for Head and Neck Squamous Cell Carcinoma.

The loss of major histocompatibility complex class I (MHC I) molecules is an important mechanism by which cancer cells escape immunosurveillance in head and neck squamous cell carcinoma (HNSCC). Several long non-coding RNAs (lncRNAs) have been implicated in immune response and regulation including antigen processing and presentation. However, few studies on lncRNAs regulating MHC I expression in HNSCC have been conducted. In this study, MHC I related lncRNAs were identified from the The Cancer Genome Atlas (TCGA) HNSCC database. One of the lncRNAs, long intergenic non-protein coding RNA 2195 (LINC02195), was found to be associated with genes encoding MHC I molecules and patient prognosis in the TCGA database. KEGG and GO analyses suggested that LINC02195 was closely related to antigen processing and presentation. qRT-PCR revealed high expression of LINC02195 in human HNSCC tissues and HNSCC cell lines compared with normal mucosal tissues. in situ hybridization of the HNSCC tissue microarray revealed a correlation between high LINC02195 expression and a favorable prognosis in our patient cohort. Silencing of LINC02195 decreased MHC I protein expression, as evidenced by western blotting. Multiplex immunochemistry was performed to reveal the positive correlation between high LINC02195 expression and an increased number of CD8+ and CD4+ T cells in the tumor microenvironment. Based on our study, LINC02195 is a promising prognostic marker and a target for future therapeutic interventions.

Expression of inositol polyphosphate 4-phosphatase type II and the prognosis of oral squamous cell carcinoma.

Inositol polyphosphate 4-phosphatase type II (INPP4B) is a phosphoinositide phosphatase that plays complex roles in the pathogenesis of different tumors. We aimed to explore the expression, clinicopathological significance, and prognostic value of INPP4B in oral squamous cell carcinoma (OSCC). Tissue microarrays that included samples from 176 primary OSCCs, 42 normal mucosae, and 69 dysplastic tissues were used for immunostaining analyses of INPP4B protein. Aperio ScanScope CS scanner and aperio quantification software were used to scan the microarrays and score the staining, respectively. We also evaluated the correlation between INPP4B expression and clinical parameters, pathological grades, node-positive status, and immune-related markers. Expression of INPP4B was statistically significantly upregulated in human primary OSCC tissues compared with dysplastic and normal tissues. Additionally, we found that patients with strong expression of INPP4B had a statistically significantly poorer overall survival than patients with weak expression of INPP4B. Furthermore, our study indicated that expression of INPP4B in OSCC was positively associated with expression of p-S6Ser235/236 , p-CADSer1859 , and certain immune checkpoints (B7-H4, Galectin-9). Therefore, INPP4B may be an independent prognostic indicator for patients with OSCC, in which it might function as an oncoprotein.

Expression and clinicopathologic significance of coxsackie-adenovirus receptor in oral squamous cell carcinoma.

OBJECTIVE: This study aimed to explore the relationship between the expression of the coxsackie-adenovirus receptor (CAR) in oral squamous cell carcinoma (OSCC) and the clinicopathologic parameters associated with the disease. The diagnostic and prognostic potential of CAR in OSCC was also investigated. STUDY DESIGN: Immunohistochemistry was performed on human tissue microarrays, containing 42 oral mucosa, 69 dysplasia, and 176 OSCC tissue sections, to reveal the expression pattern of CAR. Statistical analysis was used to determine the correlation between CAR expression and the patient survival rate as a measure of the prognostic value of CAR. RESULTS: CAR was overexpressed in human OSCC tissues (P = .002), and higher expression of CAR was associated with a lower survival rate, which was not statistically significant (P = .123). In addition, patients with OSCC in the human papillomavirus (HPV)-positive group showed significantly higher CAR expression compared with the HPV- negative group (P = .0491). CONCLUSIONS: This study indicated that CAR expression was upregulated in human OSCC and that patients with OSCC with higher expression of CAR had a lower survival rate. Moreover, CAR expression may be associated with HPV infection.