Enhancement Of Antitumor Immunity Research Articles

Targeting GSDME-mediated macrophage polarization for enhanced antitumor immunity in hepatocellular carcinoma.

Despite the notable efficacy of anti-PD1 therapy in the management of hepatocellular carcinoma (HCC) patients, resistance in most individuals necessitates additional investigation. For this study, we collected tumor tissues from nine HCC patients receiving anti-PD1 monotherapy and conducted RNA sequencing. These findings revealed significant upregulation of GSDME, which is predominantly expressed by tumor-associated macrophages (TAMs), in anti-PD1-resistant patients. Furthermore, patients with elevated levels of GSDME+ macrophages in HCC tissues presented a poorer prognosis. The analysis of single-cell sequencing data and flow cytometry revealed that the suppression of GSDME expression in nontumor cells resulted in a decrease in the proportion of M2-like macrophages within the tumor microenvironment (TIME) of HCC while concurrently augmenting the cytotoxicity of CD8 + T cells. The non-N-terminal fragment of GSDME within macrophages combines with PDPK1, thereby activating the PI3K-AKT pathway and facilitating M2-like polarization. The small-molecule Eliprodil inhibited the increase in PDPK1 phosphorylation mediated by GSDME site 1. The combination of Eliprodil and anti-PD1 was effective in the treatment of both spontaneous HCC in c-Myc + /+;Alb-Cre + /+ mice and in a hydrodynamic tail vein injection model, which provides a promising strategy for novel combined immunotherapy.

Assembly of 2′,3′-Cyclic guanosine Monophosphate-Adenosine monophosphate and their spontaneous intracellular disassembly for enhanced antitumor immunity via natural STING pathway activation

The stimulator of interferon genes (STING) pathway plays an important role in remodeling the immunosuppressive tumor microenvironment (TME). Cyclic dinucleotides (CDNs), the natural ligands of STING, activate innate immunity to enhance tumor immunogenicity. However, the anionic properties of CDNs result in poor membrane permeability, while their rapid metabolism by enzymes hinders the efficient targeting and activation of STING in vitro and in vivo. To improve the bioavailability and antitumor immunity of CDNs, we designed a hydrogen-bonding-based supramolecular approach for 2′,3′-cyclic guanosine monophosphate (GMP)-adenosine monophosphate (AMP) (cGAMP). Leveraging the synthetic molecules cytosine-uracil-hexane (CUH), we formulated supramolecular micelles of cGAMP via specific hydrogen bonds in aqueous solutions. Micelles comprising the CUH-cGAMP complex enhanced the biological efficacy of cGAMP by increasing its stability, thereby prolonging the activation of STING-mediated innate and adaptive immunity. We demonstrated that CUH-cGAMP stands as a promising candidate for immunotherapy, exhibiting significant inhibition of tumor growth in a CT26 syngeneic mouse model.

Low-dose SAHA enhances CD8+ T cell-mediated antitumor immunity by boosting MHC I expression in non-small cell lung cancer.

Non-small cell lung cancer (NSCLC) is a highly aggressive type of lung cancer with poor responses to traditional therapies such as surgery, radiotherapy, and chemotherapy. While immunotherapy has become an effective approach for treating multiple types of cancer, solid tumors frequently exhibit immune escape through various mechanisms, including downregulation of MHC I expression. However, whether the upregulation of MHC I expression can improve the immunotherapeutic effect on NSCLC remains unexplored. Suberoylanilide hydroxamic acid (SAHA) is a potent histone deacetylase (HDAC) inhibitor that has been applied clinically to treat lymphoma, but a high dose of SAHA kills tumor cells and normal cells without preference. Here, we report that low-dose SAHA enhances CD8+ T cell-mediated antitumor immunity by upregulating MHC I expression in NSCLC cells. Flow cytometric analysis, quantitative real-time PCR and western blot were used to analyze the expression of MHC I, STAT1 and Smad2/3 in both human and mouse NSCLC cell lines after SAHA treatment. The nuclear translocation of phosphorylated STAT1 and Smad2/3 was investigated by western blot and immunofluorescence staining. The mechanisms underlying STAT1 and Smad2/3 upregulation were analyzed through database searches and chromatin immunoprecipitation-qPCR. Finally, we assessed the antitumor effect of specific CD8+ T cells with SAHA treatment in vivo and in vitro. We showed that low-dose SAHA upregulated the expression of MHC I in NSCLC cell lines without affecting cell viability. We also provided evidence that high levels of MHC I induced by SAHA promoted the activation, proliferation, and cytotoxicity of specific CD8+ T cells in mouse models. Mechanistically, low-dose SAHA increased the levels of H3K9ac and H3K27ac in the promoters of the STAT1, Smad2 and Smad3 genes in NSCLC cells by inhibiting HDAC activity, resulting in elevated expression levels of STAT1, Smad2 and Smad3. The nuclear translocation of phosphorylated STAT1 and Smad2/3 markedly upregulated the expression of MHC I in NSCLC cells. Low-dose SAHA enhances CD8+ T cell-mediated antitumor immunity by boosting MHC I expression in NSCLC cells. Thus, we revealed a key mechanism of SAHA-mediated enhanced antitumor immunity, providing insights into a novel immunotherapy strategy for NSCLC.

GSK-3β in Dendritic Cells Exerts Opposite Functions in Regulating Cross-Priming and Memory CD8 T Cell Responses Independent of β-Catenin.

GSK-3β plays a critical role in regulating the Wnt/β-catenin signaling pathway, and manipulating GSK-3β in dendritic cells (DCs) has been shown to improve the antitumor efficacy of DC vaccines. Since the inhibition of GSK-3β leads to the activation of β-catenin, we hypothesize that blocking GSK-3β in DCs negatively regulates DC-mediated CD8 T cell immunity and antitumor immunity. Using CD11c-GSK-3β-/- conditional knockout mice in which GSK-3β is genetically deleted in CD11c-expressing DCs, we surprisingly found that the deletion of GSK-3β in DCs resulted in increased antitumor immunity, which contradicted our initial expectation of reduced antitumor immunity due to the presumed upregulation of β-catenin in DCs. Indeed, we found by both Western blot and flow cytometry that the deletion of GSK-3β in DCs did not lead to augmented expression of β-catenin protein, suggesting that GSK-3β exerts its function independent of β-catenin. Supporting this notion, our single-cell RNA sequencing (scRNA-seq) analysis revealed that GSK-3β-deficient DCs exhibited distinct gene expression patterns with minimally overlapping differentially expressed genes (DEGs) compared to DCs with activated β-catenin. This suggests that the deletion of GSK-3β in DCs is unlikely to lead to upregulation of β-catenin at the transcriptional level. Consistent with enhanced antitumor immunity, we also found that CD11c-GSK-3β-/- mice exhibited significantly augmented cross-priming of antigen-specific CD8 T cells following DC-targeted vaccines. We further found that the deletion of GSK-3β in DCs completely abrogated memory CD8 T cell responses, suggesting that GSK-3β in DCs also plays a negative role in regulating the differentiation and/or maintenance of memory CD8 T cells. scRNA-seq analysis further revealed that although the deletion of GSK-3β in DCs positively regulated transcriptional programs for effector differentiation and function of primed antigen-specific CD8 T cells in CD11c-GSK-3β-/- mice during the priming phase, it resulted in significantly reduced antigen-specific memory CD8 T cells, consistent with diminished memory responses. Taken together, our data demonstrate that GSK-3β in DCs has opposite functions in regulating cross-priming and memory CD8 T cell responses, and GSK-3β exerts its functions independent of its regulation of β-catenin. These novel insights suggest that targeting GSK-3β in cancer immunotherapies must consider its dual role in CD8 T cell responses.

Striking an alliance between Tcells and macrophages for enhanced cancer immunotherapy.

A new study by Yamada-Hunter etal. reveals a novel approach to promote synergy-rather than antagonism-between macrophages and engineered Tcells, leading to enhanced antitumor immunity.

KDM3A Ablation Activates Endogenous Retrovirus Expression to Stimulate Antitumor Immunity in Gastric Cancer.

The success of immunotherapy for cancer treatment is limited by the presence of an immunosuppressive tumor microenvironment (TME); Therefore, identifying novel targets to that can reverse this immunosuppressive TME and enhance immunotherapy efficacy is essential. In this study, enrichment analysis based on publicly available single-cell and bulk RNA sequencing data from gastric cancer patients are conducted, and found that tumor-intrinsic interferon (IFN) plays a central role in TME regulation. The results shows that KDM3A over-expression suppresses the tumor-intrinsic IFN response and inhibits KDM3A, either genomically or pharmacologically, which effectively promotes IFN responses by activating endogenous retroviruses (ERVs). KDM3A ablation reconfigures the dsRNA-MAVS-IFN axis by modulating H3K4me2, enhancing the infiltration and function of CD8 T cells, and simultaneously reducing the presence of regulatory T cells, resulting in a reshaped TME in vivo. In addition, combining anti-PD1 therapy with KDM3A inhibition effectively inhibited tumor growth. In conclusions, this study highlights KDM3A as a potential target for TME remodeling and the enhancement of antitumor immunity in gastric cancer through the regulation of the ERV-MAVS-IFN axis.

Enhancing antitumor immunity and achieving tumor eradication with IL11RA mRNA immunotherapy

Current methods for delivering genes to target tumors face significant challenges, including off-target effects and immune responses against delivery vectors. In this study, we developed a novel approach using messenger RNA (mRNA) to encode IL11RA for local immunotherapy, aiming to harness the immune system to combat tumors. Our research uncovered a compelling correlation between IL11RA expression and CD8 + T cell levels across multiple tumor types, with elevated IL11RA expression correlating with improved overall survival. Examination of the Pan-Cancer Atlas dataset showed a significant reduction in IL11RA expression in various cancer types compared to normal tissue, raising questions about its potential role in tumorigenesis. To achieve efficient in vivo expression of IL11RA, we synthesized two mRNA sequences mimicking the wild-type protein. These mRNA sequences were formulated and capped to ensure effective delivery, resulting in robust expression within tumor sites. Our investigation into IL11RA mRNA therapy demonstrated its effectiveness in controlling tumor growth when administered both intratumorally and intravenously in mouse models. Additionally, IL11RA mRNA treatment significantly stimulated the expansion of CD8 + T cells within tumors, draining lymph nodes, and the spleen. Transcriptome analysis revealed distinct transcriptional patterns associated with T cell functions. Using multiple deconvolution algorithms, we found substantial infiltration of CD8 + T cells following IL11RA mRNA treatment, highlighting its immunomodulatory effects within the tumor microenvironment. In conclusion, IL11RA mRNA therapy presents a promising strategy for tumor regression with potential immunomodulatory effects and clinical implications for improved survival outcomes.

Abstract PO1-04-03: Phase I/II Trial of Ibrutinib Plus Trastuzumab in HER2-Positive Metastatic Breast Cancer

Abstract Background: Ibrutinib is a first-in-class inhibitor of Bruton’s tyrosine kinase that has demonstrated potent inhibition of ErbB/HER family receptor tyrosine kinases in preclinical models. Ibrutinib also displays immunomodulatory effects, shifting the profile of the immune response from Th2-type to Th1-type cytokines (Dubovsky et al. 2013), resulting in enhanced antitumor immunity. As there is a need for novel HER2-targeted therapies following progression on established anti-HER2–directed therapies, and as combining multiple HER2-directed agents is more effective than single-agent therapy (Blackwell et al. 2012), this study explored the safety and efficacy of ibrutinib in combination with trastuzumab in patients (pts) with HER2-positive metastatic breast cancer (MBC) (NCT03379428). Trial design: Phase I was a dose-escalation study to define the recommended Phase II dose (RP2D) of ibrutinib plus trastuzumab. The primary objective of Phase II was to define the clinical benefit rate (CBR = complete response [CR] + partial response [PR] + stable disease [SD] ≥ 6 months) of ibrutinib plus trastuzumab; secondary objectives were to determine objective response rate (ORR = CR + PR), overall survival (OS), progression-free survival (PFS), and safety/tolerability. Pts had HER2-positive MBC with measurable disease per RECIST v1.1, disease progression on or within 6 months of completing ado-trastuzumab emtansine (T-DM1) therapy, and ≤4 (Phase I) or ≤5 (Phase II) prior chemotherapy regimens for MBC, with no limit on prior endocrine therapies. Results: 26 pts were treated in Phases I and II: median age, 65.1 y; 15.4% Asian, 15.4% Black, 46.2% Caucasian, 19.2% Hispanic, and 3.8% Other; 46.2% with ECOG performance status (PS) of 0, 42.3% with PS of 1, and 7.7% with PS of 2. Median prior lines of therapy for MBC was 2 (range: 0, 6); median prior lines of therapy in any setting was 4 (range: 1, 9). In any setting, 88.5% of pts had prior treatment (Tx) with trastuzumab, 80.8% had prior Tx with pertuzumab, and 100% had prior Tx with T-DM1. 0% of pts had brain, 38.5% had bone, 23.1% had liver, and 42.3% had lung metastases. All pts were HER2+ by local pathology, 61.5% positive by IHC and 42.3% by FISH; 12 pts had ER+ and/or PR+ and 14 pts had ER-/PR- cancers. The starting dose of ibrutinib for Phase I was 560 mg. Of the 3 pts enrolled at this dose level, all experienced grade 3 or higher adverse events (AEs), with 2 of the pts experiencing serious AEs (grade 4 alanine aminotransferase [ALT] increased and grade 5 respiratory failure). As such, 420 mg of ibrutinib was selected as the RP2D. At the time of data extraction, across Phase I/II, 16 pts (61.5%) experienced a Tx-related adverse event (TRAE). The most common (≥5%) TRAEs of any grade were bruising and rash (each 19.2%); fatigue and thrombocytopenia (each 15.4%); anemia, diarrhea, and edema (each 11.5%); and ALT increased, aspartate aminotransferase increased, blurred vision, ecchymoses, mucositis, nausea, pruritus, and vomiting (each 7.7%). A total of 5 pts (19.2%) experienced grade 3 or 4 TRAEs; no grade 5 TRAEs were reported. 26 pts were treated with ibrutinib and trastuzumab, and 26 pts were in the evaluable population. 1 pt had CR for an ORR of 3.8% (95% CIs: 0.1, 19.6); 9 pts had SD, and 4 pts had SD for ≥6 months for a CBR of 19.2% (95% CIs: 6.6, 39.4). Median OS was 27.1 months (range: 0.30, 27.1), and median PFS was 2.0 months (range: 0.03, 27.1). The PFS rate at 12 months was 34.6% (95% CIs: 15.6, 54.6). Conclusion: Ibrutinib plus trastuzumab had a manageable safety profile; however, the CBR did not reach the protocol-specified goal of 28%, and these results do not support further clinical investigation. An in-depth evaluation of the immune effects of ibrutinib in these pts is ongoing. Citation Format: Joyce O'Shaughnessy, Andrea Glidden, Tracy Locke, Amy Scales. Phase I/II Trial of Ibrutinib Plus Trastuzumab in HER2-Positive Metastatic Breast Cancer [abstract]. In: Proceedings of the 2023 San Antonio Breast Cancer Symposium; 2023 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2024;84(9 Suppl):Abstract nr PO1-04-03.

High Manganese Content of Lipid NanoMn (LNM) by Microfluidic Technology for Enhancing Anti-Tumor Immunity.

Immunotherapy is a clinically effective method for treating tumors. Manganese can activate the cGAS-STING signaling pathway and induce an anti-tumor immune response. However, its efficacy is hindered by non-specific distribution and low uptake rates. In this study, we employed microfluidic technology to design and develop an innovative preparation process, resulting in the creation of a novel manganese lipid nanoparticle (LNM). The lipid manganese nanoparticle produced in this process boasts a high manganese payload, excellent stability, the capacity for large-scale production, and high batch repeatability. LNM has effectively demonstrated the ability to activate the cGAS-STING signaling pathway, induce the production of pro-inflammatory cytokines, and inhibit tumor development. Notably, LNM does not require combination chemotherapy drugs or other immune activators. Therefore, LNM presents a safe, straightforward, and efficient strategy for anti-tumor immune activation, with the potential for scalable production.

Abstract LB077: CSF-1R inhibition with Pimicotinib (ABSK021) enhanced anti-tumor efficacy of KRASG12C inhibitors in preclinical non-small cell lung cancer mouse models

Abstract Background: KRAS mutations are highly prevalent oncogenic drivers in human cancers and KRASG12C is the most frequent mutations found in KRAS-mutant non-small lung cancer (NSCLC). It is reported that tumor associated macrophages (TAMs) are enriched in KRAS-driven transgenic lung cancer models. Depletion of macrophage results in a significant decrease in tumor burden and increased survival. Sotorasib (AMG510), the first KRASG12C inhibitor approved by FDA, has been found to modulate tumor immunity, impacting the recruitment of macrophages. CSF-1R signaling is critical for macrophage proliferation and survival. CSF-1R inhibition depletes TAMs and reprograms tumor microenvironment (TME), resulting in enhancement of anti-tumor immunity. Therefore, the combination of KRASG12C and CSF-1R inhibitors may synergize to enhance anti-tumor efficacy. Pimicotinib (ABSK021) is a potential best-in-class small molecule inhibitor of CSF-1R in clinical development of multiple indications. Here, we conducted in vivo experiments to explore the combined effects of KRASG12C and CSF-1R inhibitors. Methods: In vivo efficacy studies were performed to evaluate the combined treatment of KRASG12C inhibitors (AMG510 and ABSK071, a next-generation inhibitor targeting KRASG12C with better inhibitory activity) and CSF-1R inhibitor (ABSK021) in NCI-H2122 PBMC humanized mice and LLC syngeneic mice. RNA sequencing was employed to investigate the mechanism of action underlying the synergistic anti-tumor effect. Immunohistochemistry (IHC) was utilized to examine the changes of immune cell populations in TME. Results: The combinatory regimen of ABSK021 and KRASG12C inhibitors showed improved anti-tumor effects than each single agent alone in both mouse NSCLC models. Bioinformatics and follow-up analysis revealed a reduction in immune suppressive TAMs in tumors treated with ABSK021 alone or in combination with KRASG12C inhibitors. Furthermore, modulation of TME related to anti-tumor immunity, such as activated CD4 T, CD8 T and NK cells, was increased, and pro-tumor immunity, such as MDSC, regulatory T cells, was decreased in combination group. IHC results confirmed that ABSK021 addition led to macrophage depletion and more CD8 T cell infiltration in TME. Conclusions: For the first time, we demonstrate that the combined inhibition of KRASG12C and CSF-1R leads to superior therapeutic efficacy in preclinical NSCLC mouse models. This results suggests a potential novel therapeutic regimen that could yield improved clinical benefit to patients. Citation Format: Nannan Zhang, Bin Shen, Shenyan Liu, Cheng Dai, Haiyan Ying, Fushen Guo, Zhixuan Zhu, Wan Shi, Min Tu, Jie Wang, Jie Zhang, Manqi Liu, Qi Zhang, Zhui Chen. CSF-1R inhibition with Pimicotinib (ABSK021) enhanced anti-tumor efficacy of KRASG12C inhibitors in preclinical non-small cell lung cancer mouse models [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 2 (Late-Breaking, Clinical Trial, and Invited Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(7_Suppl):Abstract nr LB077.

Blocking senescence and tolerogenic function of dendritic cells induced by γδ Treg cells enhances tumor-specific immunity for cancer immunotherapy

BackgroundRegulatory T (Treg) cells are a key component in maintaining the suppressive tumor microenvironment and immune suppression in different types of cancers. A precise understanding of the molecular mechanisms used...

Abstract 4026: The combination of DLL4/VEGF-a blockade and immunomodulation can eliminate MHC class I negative tumors in mice

Abstract CTX-009 is a bispecific antibody targeting VEGF-A and DLL4 which is undergoing clinical investigation in patients with multiple tumor types, including biliary tract and colon cancers. In biliary tract cancers, checkpoint inhibitor therapy has been shown to improve outcomes when combined with chemotherapy. In an effort to increase the breadth and duration of response of CTX-009, we set out to investigate the combined anti-tumor efficacy of this bispecific antibody and immunotherapy in preclinical models. Here we report the evaluation of the combination of the mouse surrogates of CTX-009 and CTX-471, an agonistic anti-mouse CD137 antibody, or monoclonal antibodies that disrupt the PD-1/PD-L1 signaling axis. Coupling VEGF-A/DLL4 targeting with either CD137 agonism or PD-1/PD-L1 blockade markedly increased the anti-tumor efficacy of the individual treatments alone in multiple syngeneic mouse tumor models. Tumor growth inhibition was accompanied by pharmacodynamic evidence consistent with enhancement of anti-tumor immunity. Notably, the combination of CTX-009 and CTX-471 retained potent anti-tumor activity even in a tumor line (MC38) which was made MHC I deficient through the deletion of the beta 2 microglobulin gene. This system may model the clinically relevant unmet need characterized by tumor escape through the loss of antigen presentation machinery such as HLA LOH. Interestingly, the model cell lines CT26 and MC38 failed to thrive in the B2M-deficient setting and depletion of NK cells markedly increased their ability to grow. This implies that NK cells might be involved in controlling tumor growth in this setting, and that the combined action of CTX-471 and CTX-009 in the tumor stroma enhances NK cell activity. The findings presented here suggest that CTX-009 may provide enhanced clinical benefit when combined with immunomodulatory agents, such as agonistic anti-CD137 antibodies or PD-1/PD-L1 blockers in tumors where immune checkpoint inhibitors have failed. Citation Format: Diana I. Albu, Rachael Duffy, Amy Daniel Ulumben, Jason Kong, Jessica Zolotarevsky, Melissa Brundin, Mei Su, Ruturaj Jadhav, Kris F. Sachsenmeier, Bing Gong, Thomas J. Schuetz, Alberto Visintin. The combination of DLL4/VEGF-a blockade and immunomodulation can eliminate MHC class I negative tumors in mice [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 4026.

Abstract 2921: Extended treatment with IAP inhibitor xevinapant post radiotherapy improves therapeutic efficacy and promotes antitumor immunity in preclinical models

Abstract Background: Xevinapant is a first-in-class, oral IAP (inhibitor of apoptosis protein) inhibitor designed to restore cancer cell sensitivity to apoptosis induced by radiotherapy (RT) and chemotherapy. In a randomized phase 2 study of patients with unresected locally advanced squamous cell carcinoma of the head and neck, xevinapant + chemoradiotherapy (CRT) significantly improved locoregional control at 18 months, 3-year progression-free survival and nearly doubled 5-year overall survival vs. placebo + CRT (53% vs. 28%). Two phase 3 trials, in which patients receive 6 cycles of xevinapant or placebo monotherapy (3 cycles in combination with standard-of-care (C)RT followed by 3 cycles of monotherapy), are ongoing. Based on the roles of IAPs in apoptosis and tumor immunity, continual dosing of xevinapant post RT may deliver additional therapeutic benefit through modulation of multiple tumor microenvironment (TME) compartments. Methods: The impact on antitumor efficacy of xevinapant dosing duration was evaluated in A1419 (head and neck), LLC (lung) and MC38 (colorectal) syngeneic tumor-bearing mice treated with vehicle control, RT alone (3.6Gy, QD, 5 days), or RT + xevinapant (100 mg/kg, QD, 1, 2, or 4 weeks). To assess treatment-mediated TME modulation in MC38 tumors, RNAseq and FACS-based immune profiling was performed, followed by functional validation with ex vivo ELISpot assays, in vitro immunogenic cell death assays, T cell activation assays, and macrophage polarization and viability assays. To evaluate the effect of xevinapant on RT-induced cancer associated fibroblast (CAF) activation and CAF-modulated immune phenotype, activation assay and cytokine profiling was performed. Results: In the tumor models tested, RT in combination with extended xevinapant dosing markedly improved efficacy and prolonged survival compared to treatment arms of RT with shorter xevinapant dosing durations, RT alone, and vehicle control. RNAseq and FACS analyses suggested a TME with enhanced antitumor immunity, while ELISpot and in vitro T cell assays confirmed that extended xevinapant dosing promoted antigen-specific T cell response and T cell activation. Furthermore, macrophage polarization and viability assays suggested that xevinapant reduced the viability of M2 macrophages which may have contributed to the increased M1:M2 macrophage ratio and the improved antitumor immune response observed in vivo. In addition, via the suppression of RT-mediated CAF activation, xevinapant may promote M1 polarization of macrophages and recruitment of T cells by upregulating GM-CSF and CXCL10 in CAFs. Conclusions: Extended dosing of xevinapant post concurrent RT improved antitumor efficacy and prolonged survival of tumor-bearing mice. Mechanistic investigation suggested that such benefit may be, in part, modulated by xevinapant enhanced antitumor immunity. Citation Format: Tsz-Lun Yeung, Feng Jiang, Hui Huang, Huakui Yu, Li-Ya Chiu, Mathilde Bonnemaison, Bo Marelli, Roberta Ferretti, Ralph Lindemann, Christina Esdar. Extended treatment with IAP inhibitor xevinapant post radiotherapy improves therapeutic efficacy and promotes antitumor immunity in preclinical models [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 2921.

Abstract 5305: M9657, a tumor-targeted anti-CD137 agonist, induced significant antitumor immunity in combination with anti-PD-1 antibody

Abstract Background: M9657, a first-in-class tumor-targeted conditional immune agonist, was developed to boost antitumor immune responses in the tumor microenvironment (TME) by targeting CD137. The immune agonism potency of M9657 was validated through in vitro assays and in vivo efficacy studies in syngeneic tumor models using the surrogate antibody FS122m. Combining CD137 agonists and antiPD(L)-1 antibodies presents a novel therapeutic strategy to overcome immune checkpoint inhibitor (ICI) resistance and enhance antitumor activity via complementary mechanisms. Anti-PD-(L)-1 antibodies can reverse the suppressive immune signals, and CD137 agonists can boost T cell activation, improving antigen presentation and cytokine release. Methods: The antitumor immunity of M9657 + pembrolizumab (anti-PD-1 antibody) combination therapy was assessed using in-vitro luciferase and ex-vivo functional assays. In vivo antitumor efficacy was investigated with the M9657 surrogate (FS122m) and anti-mPD-1 in syngeneic tumor models expressing Mesothelin (MSLN). Results: The combination of M9657 and pembrolizumab displayed dose-dependent immune agonism potency and significantly enhanced tumor cell cytotoxicity and CD8+ T cell cytokine release relative to single agent treatments. In various syngeneic tumor models, the combination of FS122m with antimPD1 significantly increased antitumor efficacy relative to monotherapies, with more mice achieving complete tumor regression and prolonged median survival. Tumor-cured mice after combination treatment exhibited resistance to the primary tumor rechallenge, indicating the generation of tumor antigen-specific antitumor immunity and long-term immune protectivity. Conclusion: The combination of M9657 with anti-PD-(L)1 could overcome primary ICI therapy resistance and improve the antitumor efficacy of current anti-PD-(L)1 therapy in the clinic. Our findings support a combination strategy to combine M9657 with anti-PD-(L)1 in a clinical setting, potentially leading to enhanced antitumor immunity and improved patient outcomes. Future studies should investigate the safety and efficacy of this combination therapy in human patients. Sponsored by the healthcare business of Merck KGaA, Darmstadt, Germany (CrossRef Funder ID: 10.13039/100009945) Citation Format: Chunxiao Xu, Sireesha Yalavarthi, Hong Zhang, Uma Mahesh Gundra, Clotilde Bourin, Laura Helming. M9657, a tumor-targeted anti-CD137 agonist, induced significant antitumor immunity in combination with anti-PD-1 antibody [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 5305.

Low-dose targeted radionuclide therapy synergizes with CAR T cells and enhances tumor response.

Ionizing radiation has garnered considerable attention as a combination partner for immunotherapy due to its potential immunostimulatory effects. In contrast to the more commonly used external beam radiation, we explored the feasibility of combining chimeric antigen receptor (CAR) T cell therapy with targeted radionuclide therapy (TRT), which is achieved by delivering β-emitting 177Lu-DOTATATE to tumor via tumor-infiltrating CAR T cells that express somatostatin receptor 2 (SSTR2). We hypothesized that the delivery of radiation to tumors could synergize with CAR T therapy, resulting in enhanced antitumor immunity and tumor response. To determine the optimal dosage and timing of 177Lu-DOTATATE treatment, we measured CAR T cell infiltration and expansion in tumors longitudinally through positron emission tomography (PET) using a SSTR2-specific positron-emitting radiotracer,18F-NOTA-Octreotide. In animals receiving CAR T cells and a low-dose (2.5 Gy) of TRT following the administration of 177Lu-DOTATATE, we observed a rapid regression of large subcutaneous tumors, which coincided with a dramatic increase in serum proinflammatory cytokines. Tumor burden was also reduced when a higher radiation dose (6 Gy) was delivered to the tumor. However, this higher dose led to cell death in both the tumor and CAR T cells. Our study suggests that there may exist an optimum range of TRT dosage that can enhance T cell activity and sensitize tumor cells to T cell killing, which may result in more durable tumor control compared to a higher radiation dose.

Notch signaling genes and CD8+ T-cell dynamics: Their contribution to immune-checkpoint inhibitor therapy in oral squamous cell carcinoma: A retrospective study.

Aberrant Notch signaling pathway has been related with the tumorigenesis in head and neck region, involving oral cavity. Here, we report the correlation between mutations in the Notch signaling pathway and CD8+ T-cell infiltration via PD-L1, which lead to enhanced antitumor immunity and may target for immune-checkpoint inhibitors (ICIs) therapy. This retrospective study analyzed the results of immunohistochemical staining for PD-L1 and CD8+ T-cell infiltration in 10 patients and whole-exome sequencing (WES) was conducted on five of these patients to identify frequently mutated genes. Four of 10 patients were positive for PD-L1 and CD8+ T. By analyzing WES in three of these four patients, we notably identified the mutations of NOTCH1, FBXW7, and noncoding RNA intronic mutation in NOTCH2NLR in two of these three patients. This study may enable better selection of ICI therapy with CD8+ T-cell infiltration via PD-L1 expression for oral squamous cell carcinoma patients with mutations in Notch signaling pathway.

Co-delivery of doxorubicin and STING agonist cGAMP for enhanced antitumor immunity

Many chemotherapeutic agents can induce immunogenic cell death (ICD), which leads to the release of danger-associated molecular patterns (DAMPs) and tumor-associated antigens. This process promotes dendritic cells (DCs) maturation and cytotoxic T lymphocyte (CTL) infiltration. However, cancer cells can employ diverse mechanisms to evade the host immune system. Recent studies have shown that stimulator of interferon genes (STING) agonists, such as cGAMP, can amplify ICD-triggered immune responses and enhance the infiltration of immune cells into the tumor microenvironment (TME). Building upon these findings, we constructed a doxorubicin (DOX) and cGAMP co-delivery system (DOX/cGAMP@NPs) for melanoma and triple-negative breast cancer (TNBC) therapy. The results demonstrated that DOX could effectively destroy tumors and induce the release of DAMPs by ICD. Furthermore, in orthotopic 4T1 tumors mice model and subcutaneous B16 tumor mice model, cGAMP could promote the maturation of DCs and CD8+ T cell activation and infiltration by inducing the secretion of type I interferons and pro-inflammation cytokine, which amplified the antitumor immune response induced by DOX. This strategy also promoted the depletion of immunosuppressive cells, potentially alleviating the immunosuppressive TME. In conclusion, our study highlights the combination of DOX-induced ICD and the immune-enhancing properties of cGAMP holds significant implications for future research and clinical applications.

Current Technologies and Future Perspectives in Immunotherapy towards a Clinical Oncology Approach.

Immunotherapy is now established as a potent therapeutic paradigm engendering antitumor immune response against a wide range of malignancies and other diseases by modulating the immune system either through the stimulation or suppression of immune components such as CD4+ T cells, CD8+ T cells, B cells, monocytes, macrophages, dendritic cells, and natural killer cells. By targeting several immune checkpoint inhibitors or blockers (e.g., PD-1, PD-L1, PD-L2, CTLA-4, LAG3, and TIM-3) expressed on the surface of immune cells, several monoclonal antibodies and polyclonal antibodies have been developed and already translated clinically. In addition, natural killer cell-based, dendritic cell-based, and CAR T cell therapies have been also shown to be promising and effective immunotherapeutic approaches. In particular, CAR T cell therapy has benefited from advancements in CRISPR-Cas9 genome editing technology, allowing the generation of several modified CAR T cells with enhanced antitumor immunity. However, the emerging SARS-CoV-2 infection could hijack a patient's immune system by releasing pro-inflammatory interleukins and cytokines such as IL-1β, IL-2, IL-6, and IL-10, and IFN-γ and TNF-α, respectively, which can further promote neutrophil extravasation and the vasodilation of blood vessels. Despite the significant development of advanced immunotherapeutic technologies, after a certain period of treatment, cancer relapses due to the development of resistance to immunotherapy. Resistance may be primary (where tumor cells do not respond to the treatment), or secondary or acquired immune resistance (where tumor cells develop resistance gradually to ICIs therapy). In this context, this review aims to address the existing immunotherapeutic technologies against cancer and the resistance mechanisms against immunotherapeutic drugs, and explain the impact of COVID-19 on cancer treatment. In addition, we will discuss what will be the future implementation of these strategies against cancer drug resistance. Finally, we will emphasize the practical steps to lay the groundwork for enlightened policy for intervention and resource allocation to care for cancer patients.

RCAd-LTH-shPD-L1, a double-gene recombinant oncolytic adenovirus with enhanced antitumor immunity, increases lymphocyte infiltration and reshapes the tumor microenvironment

BackgroundWith the successful development of modern immunotherapy, immune checkpoint inhibitors (ICIs) are currently considered potential therapeutic options for patients with cancer. However, the therapeutic potential of ICIs in human cancer...

Enhancing antitumor immunity with stimulus-responsive mesoporous silicon in combination with chemotherapy and photothermal therapy.

Due to the immunosuppressive tumor microenvironment (TME) and potential systemic toxicity, chemotherapy often fails to elicit satisfactory anti-tumor responses, so how to activate anti-tumor immunity to improve the therapeutic efficacy remains a challenging problem. Photothermal therapy (PTT) serves as a promising approach to activate anti-tumor immunity by inducing the release of tumor neoantigens in situ. In this study, we designed tetrasulfide bonded mesoporous silicon nanoparticles (MSNs) loaded with the traditional drug doxorubicin (DOX) inside and modified their outer layer with polydopamine (DOX/MSN-4S@PDA) for comprehensive anti-tumor studies in vivo and in vitro. The MSN core contains GSH-sensitive tetrasulfide bonds that enhance DOX release while generating hydrogen sulfide (H2S) to improve the therapeutic efficacy of DOX. The polydopamine (PDA) coating confers acid sensitivity and mild photothermal properties upon exposure to near-infrared (NIR) light, while the addition of hyaluronic acid (HA) to the outermost layer enables targeted delivery to CD44-expressing tumor cells, thereby enhancing drug accumulation at the tumor site and reducing toxic side effects. Our studies demonstrate that DOX/MSN@PDA-HA can reverse the immunosuppressive tumor microenvironment in vivo, inducing potent immunogenic cell death (ICD) of tumor cells and improving anti-tumor efficacy. In addition, DOX/MSN@PDA-HA significantly suppresses tumor metastasis to the lung and liver. In summary, DOX/MSN@PDA-HA exhibits controlled drug release, excellent biocompatibility, and remarkable tumor inhibition capabilities through synergistic chemical/photothermal combined therapy.