Immune Checkpoint Inhibitor Resistance Research Articles

ARID1A is a Coactivator of STAT5 that Contributes to CD8+ T Cell Dysfunction and Anti-PD-1 Resistance in Gastric Cancer.

ARID1A deletion mutation contributes to improved treatment of several malignancies with immune checkpoint inhibitors (ICIs). However, its role in modulating of tumor immune microenvironment (TIME) of gastric cancer (GC) remains unclear. Here, we report an increase of CD8+ T cells infiltration in GC patients with ARID1A-mutation (MUT), which enhances sensitivity to ICIs. Kaplan-Meier survival analysis showed that ARID1A-mutation patients with gastrointestinal malignancies benefit from immunotherapy. Transcriptome analysis implicated that ARID1A regulates STAT5 downstream targets to inhibit T-cell mediated toxicity. Integrated dual luciferase assay and ChIP-qPCR analyses indicated that ARID1A coordinated with STAT5 to facilitate the transcription of the immunosuppressive factors TGF-β1 and NOX4. ARID1A recruited canonical BAF complex (cBAF) subunits, including SMARCB1 and SMARCD1, to sustain DNA accessibility. Downregulation of ARID1A reduced chromatin remodeling into configurations which make GC more sensitive to ICIs. In addition, targeting STAT5 effectively improved anti-PD-1 efficiency in ARID1A-wild type (WT) GC patients. Taken together, ARID1A is a coactivator of STAT5, function as a chromatin organizer in GC ICIs resistance, and targeting STAT5 is an effective strategy to improve the efficiency of ICIs in GC.

Reverse resistance to immune checkpoint inhibitor in a patient with recurrent cardia cancer by intratumoral injection of recombinant human adenovirus type 5: a case report and literature review

Advanced metastatic cardia cancer is an intractable malignance with poor prognosis. It is often accompanied by upper digestive tract obstruction, which seriously affects the quality of patients. Therefore, effective relief of eating obstruction is an important goal in the treatment of cardia cancer. Immune checkpoint inhibitors (ICIs) have shown significant efficacy in cardia cancer, but only a small percentage of patients will benefit from them due to immune resistance. Oncolytic viruses have been shown to enhance the efficacy of ICIs by altering the immune microenvironment. This indicates that oncolytic virus has the potential value of overcoming the immune resistance of cardia cancer. Here, we present a case with local recurrent and multiple metastatic cardia cancer accompanied by eating obstruction. After 4 cycles of chemotherapy plus ICI therapy, the patient´s metastases were significant shrink, but the recurrent carida lesion were almost unchanged. Then we implemented exploratory local injection of recombinant human adenovirus type 5(H101) into recurrent cardia lesion by painless gastroscopy. Surprisingly, the cardia lesion shrank significantly, and the eating obstruction was greatly relieved. We also observed a significant increase of infiltrated CD4+T cells in biopsy tissues after H101 treatment. Our study not only conformed the value of oncolytic viruses to reverse ICI resistance in patients with gastric cancer, but also revealed its underlying impact on immune microenvironment.

OSU-T315 overcomes immunosuppression in triple-negative breast cancer by targeting the ILK/NF-κB signaling pathway to enhance immunotherapeutic efficacy

Triple negative breast cancer (TNBC) is an aggressive and immunogenic subtype of breast cancer. The absence of biomarker has given immune checkpoint inhibitors (ICIs) a broad prospect in this type of breast cancer. The infiltration of regulatory T cells (Tregs) expressing transcription factor forkhead box P3 (Foxp3) in the tumor microenvironment (TME) is the key factor leading to ICIs resistance. Therefore, elimination of tumor antigen-specific Tregs may be an important aspect of improving ICIs efficacy. In this study, it based on the Gene Expression Omnibus and The Cancer Genome Atlas database, along with in vivo and in vitro experimental models, to verified that the high expression of integrin-linked kinase (ILK) in TNBC is the key differential factor leading to the high infiltration of Foxp3+-Tregs in the TME. Then, we selected ILK-specific inhibitor, OSU-T315, to intervene in vitro and vivo. Importantly, we found that OSU-T315 blocked the secretion of CCL17/CCL22 in tumor cells by inhibiting the ILK/NF-κB pathway, resulting in the apoptosis of Foxp3+-Tregs and decreased programmed cell death-1 (PD-1) expression. Therefore, our findings indicate a novel mechanism of OSU-T315 with potential therapeutic application in TNBC.

Research progress of tumor-associated macrophages in immune checkpoint inhibitor tolerance in colorectal cancer.

The relevant mechanism of tumor-associated macrophages (TAMs) in the treatment of colorectal cancer patients with immune checkpoint inhibitors (ICIs) is discussed, and the application prospects of TAMs in reversing the treatment tolerance of ICIs are discussed to provide a reference for related studies. As a class of drugs widely used in clinical tumor immunotherapy, ICIs can act on regulatory molecules on cells that play an inhibitory role-immune checkpoints-and kill tumors in the form of an immune response by activating a variety of immune cells in the immune system. The sensitivity of patients with different types of colorectal cancer to ICI treatment varies greatly. The phenotype and function of TAMs in the colorectal cancer microenvironment are closely related to the efficacy of ICIs. ICIs can regulate the phenotypic function of TAMs, and TAMs can also affect the tolerance of colorectal cancer to ICI therapy. TAMs play an important role in ICI resistance, and making full use of this target as a therapeutic strategy is expected to improve the immunotherapy efficacy and prognosis of patients with colorectal cancer.

T cells Instruct Immune Checkpoint Inhibitor Therapy Resistance in Tumors Responsive to IL-1 and TNFα Inflammation.

Resistance to immune checkpoint inhibitors (ICIs) is common, even in tumors with T cell infiltration. We thus investigated consequences of ICI-induced T cell infiltration in the microenvironment of resistant tumors. T cells and neutrophil numbers increased in ICI-resistant tumors following treatment, in contrast to ICI-responsive tumors. Resistant tumors were distinguished by high expression of IL-1 Receptor 1 (IL1R1), enabling a synergistic response to IL-1 and TNFα to induce G-CSF, CXCL1, and CXCL2 via NF-κB signaling, supporting immunosuppressive neutrophil accumulation in tumor. Perturbation of this inflammatory resistance circuit sensitized tumors to ICIs. Paradoxically, T cells drove this resistance circuit via TNF both in vitro and in vivo. Evidence of this inflammatory resistance circuit and its impact also translated to human cancers. These data support a mechanism of ICI resistance, wherein treatment-induced T cell activity can drive resistance in tumors responsive to IL-1 and TNFα, with important therapeutic implications.

Effectiveness of radiotherapy in delaying treatment changes in primary or secondary immunorefractory oligoprogressive patients: preliminary results from a single-center study.

To investigate whether the addition of radiotherapy could be an appropriate option to delay the time-to-next systemic treatment (TTNsT) in patients with oligoprogressive solid tumors who had acquired or innate resistance to immune checkpoint inhibitors (ICIs). Patients with oligoprogressive disease treated with ICIs and radiotherapy at our Institute from January 2019 to June 2023 were retrospectively identified. Patients were stratified as primary or secondary immunorefractory according to the time of onset of ICI resistance. TTNsT and Time-To-Resistance (TTR) were the primary outcomes. Secondary outcomes included: post-radiotherapy first progression-free survival (pR-PFS), Local Control (LC), Overall Survival (OS), and treatment-related toxicities. In addition, out-of-field effects (such as the abscopal effect) of radiotherapy have been hypothesized. The survival rates were analyzed using the Kaplan-Meier method and long-rank test. 40 out of 105 screened patients with oligoprogressive disease met the inclusion criteria. Of these, 28 had an acquired drug resistance while 12 had an innate drug resistance. Radiotherapy was offered as a local treatment approach in all patients. RT techniques were classified into three regimens: standard palliative hypofractionated radiotherapy (hypo-RT), stereotactic radiotherapy (SRS/SBRT), and lattice radiotherapy (LRT). After a median follow-up of 22.5months, the median TTR was 4months (range 3-4) in patients with innate resistance vs 14months (range 7-36) in patients with acquired resistance. Median TTNsT among patients with acquired and those with innate resistance was not reached (NR) vs 24months (range 7-72). Overall, only six patients suffered from a local failure. Although out-of-field effects of radiotherapy were hypothesized, we were unable to record them as they did not occur during the observation period. Regardless of the radiation dose, there was no observable ≥ Grade 2 acute or late treatment-related toxicity. Our preliminary results seem to confirm that the integration of radiotherapy and ICIs may allow for the continuation of systemic therapy beyond progression, which can have a subsequent benefit in terms of survival outcomes even in patients with innate resistance.

Mechanism of immune checkpoint inhibitor resistance in colorectal cancer patients and its interventional strategies

Mechanism of immune checkpoint inhibitor resistance in colorectal cancer patients and its interventional strategies

The Adenosinergic Pathway in Non-Small Cell Lung Cancer.

Immune checkpoint inhibitors (ICIs) targeting PD-(L)1 and CTLA-4 have revolutionized the systemic treatment of non-small cell lung cancer (NSCLC), achieving impressive results. However, long-term clinical benefits are only seen in a minority of patients. Extensive research is being conducted on novel potential immune checkpoints and the mechanisms underlying ICI resistance. The tumor microenvironment (TME) plays a critical role in modulating the immune response and influencing the efficacy of ICIs. The adenosinergic pathway and extracellular adenosine (eADO) are potential targets to improve the response to ICIs in NSCLC patients. First, this review delves into the adenosinergic pathway and the impact of adenosine within the TME. Second, we provide an overview of relevant preclinical and clinical data on molecules targeting this pathway, particularly focusing on NSCLC.

LTBR acts as a novel immune checkpoint of tumor-associated macrophages for cancer immunotherapy.

Tumor-associated macrophages (TAMs) greatly contribute to immune checkpoint inhibitor (ICI) resistance of cancer. However, its underlying mechanisms and whether TAMs can be promising targets to overcome ICI resistance remain to be unveiled. Through integrative analysis of immune multiomics data and single-cell RNA-seq data (iMOS) in lung adenocarcinoma (LUAD), lymphotoxin β receptor (LTBR) is identified as a potential immune checkpoint of TAMs, whose high expression, duplication, and low methylation are correlated with unfavorable prognosis. Immunofluorescence staining shows that the infiltration of LTBR+ TAMs is associated with LUAD stages, immunotherapy failure, and poor prognosis. Mechanistically, LTΒR maintains immunosuppressive activity and M2 phenotype of TAMs by noncanonical nuclear factor kappa B and Wnt/β-catenin signaling pathways. Macrophage-specific knockout of LTBR hinders tumor growth and prolongs survival time via blocking TAMimmunosuppressive activity and M2 phenotype. Moreover, TAM-targeted delivery of LTΒR small interfering RNA improves the therapeutic effect of ICI via reversing TAM-mediated immunosuppression, such as boosting cytotoxic CD8+ T cells and inhibiting granulocytic myeloid-derived suppressor cells infiltration. Taken together, we bring forth an immune checkpoint discovery pipeline iMOS, identify LTBR as a novel immune checkpoint of TAMs, and propose a new immunotherapy strategy by targeting LTBR+ TAMs.

Molecular Susceptibility and Treatment Challenges in Melanoma.

Melanoma is the most aggressive subtype of cancer, with a higher propensity to spread compared to most solid tumors. The application of OMICS approaches has revolutionized the field of melanoma research by providing comprehensive insights into the molecular alterations and biological processes underlying melanoma development and progression. This review aims to offer an overview of melanoma biology, covering its transition from primary to malignant melanoma, as well as the key genes and pathways involved in the initiation and progression of this disease. Utilizing online databases, we extensively explored the general expression profile of genes, identified the most frequently altered genes and gene mutations, and examined genetic alterations responsible for drug resistance. Additionally, we studied the mechanisms responsible for immune checkpoint inhibitor resistance in melanoma.

Role of gut microbiome in the outcome of lymphoma patients treated with checkpoint inhibitors-The MicroLinf Study.

Biomarkers for immune checkpoint inhibitors (ICIs) response and resistance include PD-L1 expression and other environmental factors, among which the gut microbiome (GM) is gaining increasing interest especially in lymphomas. To explore the potential role of GM in this clinical issue, feces of 30 relapsed/refractory lymphoma (Hodgkin and primary mediastinal B-cell lymphoma) patients undergoing ICIs were collected from start to end of treatment (EoT). GM was profiled through Illumina, that is, 16S rRNA sequencing, and subsequently processed through a bioinformatics pipeline. The overall response rate to ICIs was 30.5%, with no association between patients clinical characteristics and response/survival outcomes. Regarding GM, responder patients showed a peculiar significant enrichment of Lachnospira, while non-responder ones showed higher presence of Enterobacteriaceae (at baseline and maintained till EoT). Recognizing patient-related factors that may influence response to ICIs is becoming critical to optimize the treatment pathway of heavily pretreated, young patients with a potentially long-life expectancy. These preliminary results indicate potential early GM signatures of ICIs response in lymphoma, which could pave the way for future research to improve patients prognosis with new adjuvant strategies.

Peptide-stimulated T cells bypass immune checkpoint inhibitor resistance and eliminate autologous microsatellite instable colorectal cancer cells

Two hypermutated colon cancer cases with patient-derived cell lines, peripheral and tumor-infiltrating T cells available were selected for detailed investigation of immunological response.T cells co-cultured with autologous tumor cells showed only low levels of pro-inflammatory cytokines and failed at tumor recognition. Similarly, treatment of co-cultures with immune checkpoint inhibitors (ICI) did not boost antitumor immune responses. Since proteinase inhibitor 9 (PI-9) was detected in tumor cells, a specific inhibitor (PI-9i) was used in addition to ICI in T cell cytotoxicity testing. However, only pre-stimulation with tumor-specific peptides (cryptic and neoantigenic) significantly increased recognition and elimination of tumor cells by T cells independently of ICI or PI-9i.We showed, that ICI resistant tumor cells can be targeted by tumor-primed T cells and also demonstrated the superiority of tumor-naïve peripheral blood T cells compared to highly exhausted tumor-infiltrating T cells. Future precision immunotherapeutic approaches should include multimodal strategies to successfully induce durable anti-tumor immune responses.

Pharmacokinetic (PK) and pharmacodynamic (PD) findings from a phase 1b study of ATR inhibitor tuvusertib + anti-PD-L1 avelumab in patients with advanced unresectable solid tumors.

2614 Background: Ataxia telangiectasia and Rad3-related protein (ATR) kinase is critical in the DNA damage response, and its inhibition modulates antitumor immunity. The combination of ATR inhibitor (ATRi) + immune checkpoint inhibitor (ICI) has shown activity in patients with ICI-resistant tumors and may have the potential to overcome ICI resistance and induce antitumor immune responses. Methods: Part B1 of the open-label, multicenter study DDRiver Solid Tumors 320 investigated safety, tolerability, PK, and PD, including effects on immune cells, of ATRi tuvusertib in combination with the ICI avelumab (anti-PD-L1) in patients with advanced unresectable solid tumors. Flow cytometry was used to analyze tuvusertib target inhibition via γ-H2AX modulation in the CD45+ fraction of ex-vivo stimulated peripheral blood mononuclear cells, and to explore the effect on the peripheral immunophenotype. Tuvusertib PK samples were analyzed by a validated bioanalytical liquid chromatography/mass spectrometry method. Results: 22 patients were enrolled and treated with tuvusertib 180 mg once daily on a schedule of 2 weeks (w) on treatment followed by a treatment break of 1 or 2 w, and avelumab 800 mg once every 2 weeks (Q2W). The 2 w on/1 w off schedule, corresponding to the recommended dose for expansion (RDE) for tuvusertib monotherapy, was chosen for further exploration. At this schedule, 2 of 9 patients evaluable for dose-limiting toxicity (DLT) experienced DLTs: Grade 3 ALT and Grade 3 AST increase (n=1), and Grade 3 anemia requiring transfusion (n=1). A patient with chordoma experienced a RECIST v1.1 partial response. Preliminary PK data for tuvusertib suggested rapid absorption with median Tmax range of ~2–3 h and mean elimination half-life range of ~2.93 to 4.23 h, with ~2-fold accumulation of steady-state area-under-the-curve following multiple doses. Exposure of tuvusertib in combination with avelumab was consistent with tuvusertib monotherapy exposure (1). PD showed complete or almost complete target inhibition at 1–6 h after tuvusertib 180 mg followed by rebound above baseline after 24 h on days 1 and 8 of cycle 1. No clear trend of variation in absolute counts of myeloid-derived suppressor cells, T and B lymphocytes, monocytes, and natural killer cell subtypes was detected. Conclusions: Tuvusertib and avelumab were combined at established monotherapy doses with no new safety findings. Tuvusertib PD and exposure data were in line with monotherapy observations. The combination did not cause any consistent change of the immunophenotype. Given the accumulating evidence of ATRi as an immunosensitiser (2), further evaluation of this combination in patients with ICI-resistant advanced solid tumors is warranted. 1. Yap T et al., Ann Oncol 2022;33(suppl_7):S197–S224. 2. Besse B et al., JTO 2022;17(suppl_9):S41–S42. Clinical trial information: NCT05396833 .

A phase II trial of nivolumab plus axitinib in patients with anti-PD1 refractory advanced melanoma.

TPS9600 Background: A significant portion of patients (pts) with advanced melanoma (mel) either do not respond or become refractory to immune checkpoint inhibitor (ICI) therapy, with no established second line treatment regimen. A key ICI resistance mechanism includes formation of an immunosuppressive tumor microenvironment (TME). We have shown that high oxidative metabolism (OXPHOS) of mel tumor cells is associated with a hostile TME (1). Furthermore, this is associated with high intra-tumoral hypoxia (ITH). In mel tumor cells with high OXPHOS, CD8+ tumor infiltrating lymphocytes (TIL) display increased exhaustion and decreased functionality (decreased IFN-γ and TNF-α production). Pts with metastatic mel who progressed on ICI had tumor cells with high OXPHOS and ITH. Axitinib is a VEGFR small molecule tyrosine kinase inhibitor with high inhibitory activity for VEGFR 1-3. We previously showed that low dose axitinib reduces ITH in B16 murine mel, and our pre-clinical data show that axitinib synergizes with ICI to produce an improved tumor response (2). We hypothesize that axitinib will re-sensitize mel to ICI by modulating angiogenesis and reducing ITH and resultant T cell dysfunction. Methods: This is an investigator-initiated, single arm phase II trial of nivolumab plus axitinib for pts with unresectable stage III or IV cutaneous, acral, or mucosal mel who have progressed on prior anti-PD1 based therapy in the adjuvant or metastatic setting (NCT04493203). Pts previously treated with concomitant anti-CTLA4, anti-LAG3, BRAF/MEK inhibitors, and/or pts with brain metastases (asymptomatic or stable treated disease x 2 weeks) are eligible. Pts will receive nivolumab 480 mg IV every 4 wks with axitinib PO 5 mg twice daily for up to 2 years, or until progression or unacceptable toxicity. Pts will undergo biopsy at baseline and at 12 wks, with optional biopsy at progression. Pts will receive an oral dose of pimonidazole 0.5 mg/m2 prior to each biopsy to permit in-vivo evaluation of ITH. Staging scans (full body PET-CT or CT and MRI brain) will be obtained at baseline, with restaging scans at 12 week intervals. Primary endpoint: overall response rate (ORR) by RECIST 1.1. Responses are determined by Blinded Independent Central Review (BICR). Secondary endpoints: safety analysis, progression-free survival (PFS) and overall survival (OS). Extensive correlative translational analyses will focus on immunophenotypic changes in the TME, ITH, profiling of tumor cell metabolism, and TIL function. The null hypothesis that the true ORR is 10% will be tested versus a one-sided alternative hypothesis of ≥25%, using Simon’s minimax two-stage design. This design has a type I error rate 0.08 and power 0.81 when the true response rate is 0.25. PFS and OS will be estimated via Kaplan-Meier method. 31 of planned 31 pts have been enrolled in January 2024, with no data analysis yet available. 1. Najjar et al., JCI Insight 2019. 2. Scharping et al., Nat Immunol 2021. Clinical trial information: NCT04493203 .

A phase 2, multicenter, open-label, dose-optimization study evaluating telomere-targeting agent THIO sequenced with cemiplimab in patients with advanced NSCLC: Updated results.

8601 Background: Despite recent approvals for the first-line (1L) treatment of advanced non-small-cell lung cancer (NSCLC), long-term prognosis remains poor with a 5-year survival rate of 28% and limited options exist in patients (pts) refractory or resistant to immune checkpoint inhibitors (ICI). THIO (6-thio-2’-deoxyguanosine) is a small molecule, first-in-class direct cancer telomere-targeting agent that selectively targets telomerase positive (TERT+) cancer cells. It is incorporated de novo in synthesized telomeres leading to chromatin uncapping, generation of DNA damage signals, and rapid apoptosis. In advanced cancer animal models, THIO followed by an ICI demonstrated the ability to overcome ICI resistance. Methods: Here we describe a phase 2 dose-optimization study (NCT05208944) for adults with advanced NSCLC who progressed or relapsed after 1–4 prior treatment (tx) lines including 1L ICI alone or in combination with platinum chemotherapy. Following a safety lead-in of 10 pts who received THIO 360 mg IV [120 mg QD, D1–3] followed by 350 mg IV cemiplimab on D5 Q3W, the study proceeded to a 2-stage design with pts randomized to 1 of 3 arms: THIO 60 mg, 180 mg, or 360 mg, all followed by cemiplimab Q3W. In Stage 1 if at least 8 of 19 pts/arm achieved disease control, an additional 22 pts could be enrolled in that arm (up to 41 pts/arm). Study endpoints include safety (DLTs and AEs/SAEs) and efficacy (ORR, DCR, DOR, PFS, and OS). Results: Recruitment into the 360 mg arm was paused after 4 pts following 1 instance of G4 ALT Increase and AST Increase (without clinical presentation). At the end of Stage 1 cut-off (13-Nov-2023), the DCR greatly exceeded the threshold required for Stage 2 expansion in both arms: 60 mg 14/16 (88%); 180 mg 11/13 (85%). The 180 mg dose was selected for further investigation by the trial’s Safety Review Committee based on superior efficacy (31% PR rate; 54% reduction in tumor burden). As of 8-Jan-2024, 56 pts received ≥1 dose of THIO in the 60 and 180 mg arms (24 and 32 pts, respectively). Prior lines of tx at study entry were: 60 mg (1L 75%, 2L 21%, 3L 4%); 180 mg (1L 66%, 2L 31%, 4L 3%). Most pts received platinum chemotherapy prior to study entry (60 mg 88%; 180 mg 78%). Across all pts treated n=70, most AEs were G1/2. The most frequent related AEs were AST increase (23%), ALT increase (20%), and nausea (11%). All instances of LFT elevations were without clinical symptoms and resolved to baseline. Conclusions: THIOfollowed by cemiplimab was generally well tolerated in this difficult-to-treat population (all pts progressing following ICI tx and the majority following platinum chemotherapy). Based on safety and promising efficacy, the 180 mg dose was selected for further development. Enrollment is ongoing and is expected to be completed in Feb-2024. Updated primary endpoint data, including preliminary durability data, will be presented. Clinical trial information: NCT05208944 .

Effect of aberrant N-glycosylation of PD-L1 on the potency of anti-PD-1 treatments.

e14599 Background: Immune checkpoint inhibitors (ICIs) targeting the PD1/PDL1 axis have revolutionized the way we treat cancer patient. Yet, response rate to these treatments remains low. Post translational modifications of PD-L1 in the form of N-glycosylation play a crucial role in both receptor-ligand interaction and in the potency of PD1/PDL1 ICIs. Understanding the effect of each N-glycosylation site is crucial for patient stratification for treatment groups and may help to increase response rate to anti-PD1/PDL1 ICIs. We recently developed the Immune-Checkpoint Artificial Reporter (IcAR) technology to assess specific ICI potency for target tumors including clinical samples. Using IcAR expressing recombinant human PD1 receptor we can analyze clinical response of patients to PD1-PDL1 blocking drugs and analyze the glycan-modified PDL1 expressing cancer cells. Methods: We have created two cell lines (MDA-MB231 and MCF7) overexpressing PD-L1 in its wildtype form, single mutated glycosylation sites (N35A, N192A, N200A, N219A) and all sites mutated together (Nx4). Using IcAR-PD1 we measured the functional binding of the different mutated cell lines, cell derived xenografts (CDX) and fixed cell samples to evaluate baseline binding. Later we have incubated IcAR-PD1 and mutated cell liens together with multiple clinically used PD1/PDL1 ICIs to evaluate the inhibition of interaction of each ICI. Results: While staining and functional interaction of PDL1 and single mutants is similar, removing all four N-glycosylation sites (Nx4) decreased both the staining of PDL1 and functional binding. Interestingly, blocking capacity of different ICIs was impaired by N35A PDL1 mutation, and was absolute through all concentration (2.5 to 40 ug/mL) when employed on the Nx4 cell lines. While anti-PDL1 ICIs were managed to block PD-1/PD-L1 interaction trough all cell lines and mutants, the inhibitory capacity of anti-PD1 ICIs was impaired by glycosylation, especially on N35. Conclusions: Aberrant glycosylation of PD-L1 impair the potency of anti-PD-1 treatment in cancer cell lines. These results might explain why patients with negative PD-L1 staining (Nx4), might respond to ICIs, and suggest an explanation of mechanism in which patients with high PD-L1 staining (i.e. N35), might not respond to anti-PD-1 treatments. Our results shed a light on the mechanism of ICI resistance and response – using this knowledge patient will be stratify better into treatment groups, getting oncology a step closer to precision immunology.

MIIP downregulates PD-L1 expression through HDAC6 in cutaneous melanoma

PurposeImmune checkpoint inhibitors have improved the objective response rate and survival of melanoma patients. However, there are still many melanoma patients suffering from disease progression due to primary or secondary immune checkpoint inhibitor resistance, as is observed in the failure of anti-PD1/PD-L1 therapy. While the expression of valuable markers, such as TMB, MSI, and PD-L1, could serve as effective predictors of anti-checkpoint inhibitor therapies, tumor cell PD-L1 expression and its regulating mechanism would significantly affect the anti-PD-1 immunotherapy response and efficacy. Therefore, it is urgent to determine the function of PD-1/PD-L1 expression in melanoma and its associated pathways to enhance the efficacy of anti-PD-1 therapies.MethodsA cohort of 133 patients with histologically confirmed melanoma from Tianjin Medical University Cancer Institute & Hospital were included in this study. We performed immunohistochemical staining to detect the expression of Migration and invasion inhibitory protein (MIIP), HDAC6 and PD-L1. Kaplan–Meier and log-rank test were used for survival analysis. As for vitro, Western blot was used in melanoma cell lines to verify the signaling pathway that MIIP regulates PD-L1 expression.ResultsMIIP expression was decreased in melanoma and that the negative expression of MIIP was correlated with worse overall survival. The positive expression of HDAC6, a molecule that is downstream of MIIP, had a positive trend with decreased overall survival. At the same time, the positive expression of PD-L1, a crucial costimulatory molecule, was associated with decreased overall survival. Furthermore, there was a positive association between HDAC6 and PD-L1 protein expression (p < 0.01), and this correlation is more prominent in cutaneous melanoma than acral melanoma. In cutaneous melanoma cell lines, we found that increasing MIIP led to decreased HDAC6, pSTAT3, and PD-L1 expression. Knocking down MIIP led to increased HDAC6, pSTAT3, and PD-L1 expression. Combining the published results, showing that HDAC6 can regulate PD-L1 expression through STAT3, our present data suggest that MIIP inhibits the expression of PD-L1 by downregulating HDAC6 in melanoma. Most importantly, methods for targeting MIIP-HDAC6-PD-L1 pathways, such as treatment with HDAC6 inhibitors, might indicate a new therapeutic approach for enhancing immune checkpoint inhibitor therapies in melanoma.ConclusionsOur findings highlight the immunomodulatory effects of MIIP in the inhibition of PD-L1 expression by downregulating HDAC6 in melanoma. Methods for targeting MIIP-HDAC6-PD-L1 pathways might be new therapeutic approaches for enhancing immune checkpoint inhibitor therapies in melanoma.

Multi-omics analysis of macrophage-associated receptor and ligand reveals a strong prognostic signature and subtypes in hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is a significant contributor to morbidity and mortality worldwide. The interaction between receptors and ligands is the primary mode of intercellular signaling and plays a vital role in the progression of HCC. This study aimed to identify the macrophage-related receptor ligand marker genes associated with HCC and further explored the molecular immune mechanisms attributed to altered biomarkers. Single-cell RNA sequencing data containing primary and recurrent samples were downloaded from the China National GeneBank. Cell types were first identified to explore differences between immune cells from different sample sources. CellChat analysis was used to infer and analyze intercellular communication networks quantitatively. Three molecular subtypes were constructed based on the screened twenty macrophage-associated receptor ligand genes. Bulk RNA-Seq data were downloaded from The Cancer Genome Atlas and Gene Expression Omnibus databases. After the screening, the minor absolute shrinkage and selection operator (LASSO) regression model was employed to identify key markers. After collecting peripheral blood and clinical information from patients, an enzyme-linked immunosorbent assay (ELISA) was used to detect the correlation between key markers and IL-10, one of the macrophage markers. After developing a new HCC risk adjustment model and conducting analysis, it was found that there were significant differences in immune status and gene mutations between the high-risk and low-risk groups of patients based on macrophage-associated receptor and ligand genes. This study identified SPP1, ANGPT2, and NCL as key biological targets for HCC. The drug-gene interaction network analysis identified wortmannin, ribavirin, and tarnafloxin as potential therapeutic drugs for the three key markers. In a clinical cohort study, patients with immune checkpoint inhibitor (ICI) resistance had significantly higher expression levels of OPN, ANGPT2, NCL, and IL-10 than patients with ICI-responsiveness. These three key markers were positively correlated with the expression level of IL-10. The signature based on macrophage-associated receptor and ligand genes can accurately predict the prognosis of patients with HCC and the sensitivity to immunotherapy. These results may help guide the development of targeted prevention and personalized treatment of HCC.

Janus kinase inhibitor overcomes resistance to immune checkpoint inhibitor treatment in peritoneal dissemination of gastric cancer in C57BL/6 J mice

BackgroundCancer immunotherapy aims to unleash the immune system’s potential against cancer cells, providing sustained relief for tumors responsive to immune checkpoint inhibitors (ICIs). While promising in gastric cancer (GC) trials, the efficacy of ICIs diminishes in the context of peritoneal dissemination. Our objective is to identify strategies to enhance the impact of ICI treatment specifically for cases involving peritoneal dissemination in GC.MethodsThe therapeutic efficacy of anti-PD1, CTLA4 treatment alone, or in combination was assessed using the YTN16 peritoneal dissemination tumor model. Peritoneum and peritoneal exudate cells were collected for subsequent analysis. Immunohistochemical staining, flow cytometry, and bulk RNA-sequence analyses were conducted to evaluate the tumor microenvironment (TME). A Janus kinase inhibitor (JAKi) was introduced based on the pathway analysis results.ResultsAnti-PD1 and anti-CTLA4 combination treatment (dual ICI treatment) demonstrated therapeutic efficacy in certain mice, primarily mediated by CD8 + T cells. However, in mice resistant to dual ICI treatment, even with CD8 + T cell infiltration, most of the T cells exhibited an exhaustion phenotype. Notably, resistant tumors displayed abnormal activation of the Janus Kinase-Signal Transducer and Activator of Transcription (JAK-STAT) pathway compared to the untreated group, with observed infiltration of macrophages, neutrophils, and Tregs in the TME. The concurrent administration of JAKi rescued CD8 + T cells function and reshaped the immunosuppressive TME, resulting in enhanced efficacy of the dual ICI treatment.ConclusionDual ICI treatment exerts its anti-tumor effects by increasing tumor-specific CD8 + T cell infiltration, and the addition of JAKi further improves ICI resistance by reshaping the immunosuppressive TME.

Acquired resistance to immunotherapy and chemoradiation in MYC amplified head and neck cancer

The proto-oncogene MYC encodes a nuclear transcription factor that has an important role in a variety of cellular processes, such as cell cycle progression, proliferation, metabolism, adhesion, apoptosis, and therapeutic resistance. MYC amplification is consistently observed in aggressive forms of several solid malignancies and correlates with poor prognosis and distant metastases. While the tumorigenic effects of MYC in patients with head and neck squamous cell carcinoma (HNSCC) are well known, the molecular mechanisms by which the amplification of this gene may confer treatment resistance, especially to immune checkpoint inhibitors, remains under-investigated. Here we present a unique case of a patient with recurrent/metastatic (R/M) HNSCC who, despite initial response to nivolumab-based treatment, developed rapidly progressive metastatic disease after the acquisition of MYC amplification. We conducted comparative transcriptomic analysis of this patient’s tumor at baseline and upon progression to interrogate potential molecular processes through which MYC may confer resistance to immunotherapy and/or chemoradiation and used TCGA-HNSC dataset and an institutional cohort to further explore clinicopathologic features and key molecular networks associated with MYC amplification in HNSCC. This study highlights MYC amplification as a potential mechanism of immune checkpoint inhibitor resistance and suggest its use as a predictive biomarker and potential therapeutic target in R/M HNSCC.