Journal for Immunotherapy of Cancer最新文献

Background: Myeloid-derived suppressor cells (MDSCs) have a dominating presence in the postoperative period, mediating the suppression of natural killer (NK) cells and promoting cancer metastases after surgery. However, their phenotype and effects on postoperative cellular immunity remain incompletely understood. This study aims to functionally characterize surgery-induced (sx) MDSCs and identify potential therapeutic strategies to mitigate their immunosuppressive effects.

Methods: We used multicolor flow cytometry to characterize sx-MDSCs from n=55 patients with cancer undergoing surgery at various time points. Furthermore, single-cell RNA sequencing was performed on a cohort of patients. Our functional ex vivo sx-MDSC:NK cell suppression assay was used to investigate the activity of sx-MDSCs and to screen a 147 small molecule library to identify sx-MDSC antagonists. Lastly, we used preclinical murine models of postoperative metastases to evaluate the therapeutic potential of the inhibitors identified.

Results: Sx-MDSCs significantly expanded after surgery and single-cell RNA sequencing identified signatures resembling immunosuppressive monocytes, including an upregulation of PI3K signaling. These sx-MDSCs also suppressed NK cell activity from patient samples and the small molecule screen identified PI3K-γ inhibitors as potent modulators of sx-MDSC activity. In our murine models, inhibiting PI3K-γ with specific inhibitors reduced postoperative metastases, further corroborating the role of this pathway in sx-MDSC-mediated immune suppression.

Conclusions: Our findings highlight the critical role of PI3K-γ signaling in postoperative sx-MDSC-mediated immune suppression. Targeting this pathway with PI3K-γ inhibitors represents a promising therapeutic strategy to prevent NK cell suppression and reduce postoperative metastases.

Background: Non-small cell lung cancer (NSCLC) is the most common type of lung cancer and the leading cause of cancer-related deaths. Immune checkpoint inhibitors (ICIs) of programmed death-1 (PD-1)/programmed death ligand-1 signaling induce tumor regression in some patients with NSCLC, but most patients with NSCLC exhibit resistance to ICIs therapy. NSCLC shapes the potent tumor immunosuppressive microenvironment (TIME) that underlies tumor immune tolerance and acquired resistance. Therefore, elucidating the cellular and molecular mechanisms by which NSCLC establishes and sustains the TIME is essential for developing novel strategies to overcome immune resistance and enhance the clinical benefit of ICIs.

Methods: The correlation between sterile alpha motif domain and histidine-aspartate domain-containing protein 1 (SAMHD1) expression and ICIs was analyzed via immunohistochemistry. Cell migration assay was performed to assess the effect of SAMHD1 on macrophage recruitment. Multicolor flow cytometry was performed to analyze the effect of SAMHD1 knockdown on the tumor microenvironment. SAMHD1 regulation of the dual specificity phosphatase 6-extracellular regulated protein kinases 1/2 (DUSP6-ERK1/2) pathway was verified by RNA sequencing and western blotting.

Results: Here, we identify the SAMHD1 as a potential therapeutic target and a major determinant of poor response to ICIs in patients with NSCLC. Tumors with high SAMHD1 expression show resistance to anti-PD-1 antibody (αPD-1) treatment, whereas tumors with low SAMHD1 expression are highly sensitive. SAMHD1-dependent resistance to αPD-1 is characterized by increased tumor-associated macrophages (TAMs) infiltration and reduced CD8+T cell numbers. Mechanistically, SAMHD1 regulates the expression of macrophage-associated chemokines by influencing the activation of the DUSP6-ERK1/2 pathway, which contributes to TAMs aggregation within NSCLC tumors to shape an immunosuppressive microenvironment. The HIV accessory protein viral protein-x (VPX) specifically degrades SAMHD1 to promote HIV replication. Similarly, the vpx-engineered oncolytic adenovirus (oAd-vpx) targets SAMDH1 degradation to enhance oncolytic adenovirus replication and weaken the hostile immune microenvironment shaped by TAMs, thereby triggering a CD8+T-cell-dependent antitumor immune response. The combination of oAd-vpx and αPD-1 inhibits tumor growth and enhances sensitivity to ICIs in both mouse and human NSCLC.

Conclusions: This research identifies a key mechanism of SAMHD1-driven immunosuppression and highlights its important role in oncolytic adenovirus therapy. This study provides a theoretical basis for targeting SAMHD1 as a drug therapy strategy in patients with NSCLC.

Background: Chimeric antigen receptor (CAR) T cell therapy has shown remarkable success in hematologic malignancies but faces substantial challenges in solid tumors. One of the main obstacles is the extracellular matrix (ECM), which serves as the physical barrier that hinders T cell infiltration into tumor tissues.

Methods: We engineered CAR-T cells targeting mesothelin or B7H3 to co-express matrix metalloproteinase-3 (MMP3). We evaluated the effects of MMP3 overexpression on CAR-T cell proliferation, activation, cytotoxicity, and tumor infiltration using both in vitro Matrigel-based assays and in vivo xenograft and syngeneic models enriched with cancer-associated fibroblasts (CAFs).

Results: MMP3 overexpression did not impair CAR-T cell proliferation, activation, or cytotoxicity. However, it significantly enhanced their capacity to invade through ECM and improved tumor cell killing in vitro. In CAF-enriched xenograft models, MMP3-engineered CAR-T cells demonstrated superior tumor infiltration, expansion, and antitumor activity. Notably, MMP3 overexpression rescued the function of B7H3 CAR-T cells in the stringent CAF-enriched tumor microenvironment, while conventional CAR-T cells showed limited activity. Importantly, MMP3 overexpression also conferred potent antitumor activity in an immunocompetent mouse model, underscoring its therapeutic benefit in a more physiologically and clinically related setting.

Conclusions: These findings suggest that MMP3 engineering is a simple yet effective strategy to overcome stromal barriers and enhance the efficacy of CAR-T cell therapy in solid tumors.

Purpose: This study was conducted to assess the clinical significance of programmed cell death-ligand 1 (PD-L1)-positive circulating tumor cells (CTCs) as predictive biomarkers for the efficacy of PD-(L)1 inhibitor-based treatment in advanced hepatocellular carcinoma (HCC).

Experimental design: We enrolled 59 patients with unresectable HCC who received immunotherapy-based treatment and analyzed CTCs, PD-L1⁺CTCs and molecules in peripheral blood. An innovative telomerase reverse transcriptase-based method was applied to detect specific CTCs. Kaplan-Meier analysis and Cox regression were used to evaluate clinical outcomes, such as progression-free survival (PFS) and overall survival (OS).

Results: CTCs were detected in 86.4% (51/59) of patients, with a PD-L1-positive rate of 83.7% (41/49). Compared with the "PD-L1⁺CTC Low" group, the "PD-L1⁺CTC High" group had significantly shorter PFS (median PFS: 7.72 vs 16.1 months, p=0.037) and shorter OS (median OS: 13.89 vs 36.97 months, p=0.031). The "PD-L1⁺CTC Fewer & Low" group had the longest survival outcomes (median PFS: 17.03 months, median OS: 36.97 months), whereas the "PD-L1⁺CTC More & High" group had the poorest outcomes (median PFS: 5.3 months, median OS: 10.77 months) (p<0.05). Multivariate analysis revealed that the PD-L1⁺CTC count and ratio were an independent predictor of PFS. Significant correlations were found between PD-L1⁺CTC and several immune-related molecules, such as immune checkpoint molecules (CD28, TIM-3, and CD80) and regulatory factors (BDNF, and BLTA).

Conclusions: PD-L1⁺CTCs are potential indicators correlating with the shorter PFS and OS of immunotherapy-based treatment in patients with advanced HCC. The "PD-L1⁺CTC Low & Fewer" classification was associated with better clinical outcomes and immune-related molecules.

Background: Insufficient infiltration of CD8⁺ T cells in the tumor microenvironment (TME) critically restricts antitumor immunity and cancer immunotherapy efficacy. The purpose of this study was to identify novel tumor cell-intrinsic regulators of T-cell infiltration and to elucidate their mechanisms of action.

Methods: We performed a genome-wide Sleeping Beauty transposon mutagenesis screen in murine breast cancer models. Protein-protein interactions were identified by mass spectrometry and validated by co-immunoprecipitation. Gene and protein expression levels were assessed by reverse transcription and quantitative PCR and western blotting. T-cell infiltration and function were evaluated using flow cytometry, immunohistochemistry (IHC), multiplex IHC, and by analyzing bulk and single-cell RNA sequencing data complemented by bioinformatic analysis. The specific dephosphorylation sites on LGALS1 were confirmed through phosphomimetic mutant experiments. T-cell infiltration was further validated using an in vitro T-cell transendothelial migration assay and in vivo mouse models.

Results: Our screening identified 39 candidate genes, with tumor cell-intrinsic dual-specificity phosphatase 22 (DUSP22) expression correlating with enhanced CD8⁺ T-cell accumulation and suppressed tumor progression. Overexpression of DUSP22 resulted in increased CD8⁺ T-cell infiltration and enhanced T-cell function. Mechanistically, DUSP22 binds to LGALS1 and dephosphorylates it at the Ser8 and Thr58 residues, leading to LGALS1 degradation and subsequent alleviation of LGALS1-mediated immunosuppression. In human breast cancer samples, LGALS1 expression was negatively correlated with both DUSP22 levels and CD8⁺ T-cell infiltration. Therapeutic targeting of the DUSP22-LGALS1 axis significantly enhanced CD8⁺ T-cell infiltration and synergized with anti-programmed cell death protein-1 therapy to boost antitumor responses.

Conclusions: Our findings unveil a novel phosphorylation-dependent DUSP22-LGALS1 axis that reprograms the immunosuppressive TME. This work thus proposes a promising therapeutic strategy to overcome immune checkpoint blockade resistance in breast cancer.

Background: Nanosecond pulsed electric field (nsPEF) ablation has demonstrated limited and transient efficacy in suppressing tumor progression. Oncolytic peptide LTX-315 is known to elicit a strong antitumor immune response and durable immune memory. This study aimed to investigate whether LTX-315 could enhance nsPEF-induced antitumor immunity in liver cancer.

Methods: Both cell assays and mouse models were used to evaluate the therapeutic efficacy of nsPEF, LTX-315, and combination therapy. Flow cytometry and immunofluorescence were performed to assess the tumor immune microenvironment. Co-culture models were established to evaluate the functional modulation of immune cells.

Results: nsPEF upregulated the programmed cell death 1 ligand 1 (PD-L1) expression in liver cancer cells, leading to CD8⁺ T-cell dysfunction. LTX-315 reduced the nsPEF-mediated elevated PD-L1 level and restored the cytotoxicity of CD8+ T cells. Furthermore, LTX-315 acted with nsPEF to induce enhanced immunogenic cell death for the activation of dendritic cells and CD8+ T cells. In addition, LTX-315 improved antigen processing and presentation in nsPEF-treated liver cancer cells. Notably, the combination of nsPEF and LTX-315 achieved durable tumor control and prolonged survival of the tumor-bearing mice, by promoting the migration of dendritic cells to tumor-draining lymph nodes, the infiltration of immune cells within the tumor and potential immune memory to prevent tumor metastasis.

Conclusions: LTX-315 functions as an immune stimulant to improve the antitumor efficacy of nsPEF. The combination of nsPEF and LTX-315 represents a promising interventional immunotherapy strategy for liver cancer.

Key points: LTX-315; Antitumor immune response; nsPEF; Liver cancer.

Background: Tumor-associated macrophages (TAMs) are key drivers of the immunosuppressive tumor microenvironment (TME), thereby limiting the efficacy of immune checkpoint inhibitors (ICIs). However, the underlying mechanisms remain unclear.

Methods: Both genetic (Akr1b3 knockout) and pharmacologic (epalrestat) approaches were employed to examine the impact of Aldo-keto reductase family 1 member B1 (AKR1B1) inhibition on TAMs and T-cell function in vitro and in vivo. Mechanistic insights were obtained through RNA sequencing, flow cytometry, immunofluorescence staining, and co-culture assays. To assess therapeutic relevance, 4T1 breast cancer and LLC lung carcinoma mouse models were used to evaluate the effects of epalrestat on tumor growth, immune infiltration, and T-cell responses. Clinical relevance was validated in patient cohorts with triple-negative breast cancer (TNBC) and lung adenocarcinoma (LUAD).

Results: AKR1B1 is highly expressed in TAMs and correlates with CD8⁺ T-cell dysfunction. Targeting AKR1B1 enhances antitumor immunity by reprogramming TAMs. Mechanistically, AKR1B1 modulates macrophage metabolism via the glutathione/reactive oxygen species axis, suppressing nuclear factor κB activation and downregulating C-C motif chemokine ligand 5 (CCL5) production, thereby inducing CD8⁺ T-cell dysfunction and establishing an immunosuppressive TME. Inhibition of AKR1B1, either by gene knockout or selective pharmacologic blockade, reprograms TAMs toward an immunostimulatory phenotype, increases CCL5-CCR5 (C-C motif chemokine receptor 5) signaling, restores CD8⁺T cell effector function, and strengthens antitumor immunity. Clinically, high AKR1B1 expression is associated with poor prognosis and immune suppression in TNBC and LUAD. Notably, targeting AKR1B1 improves responses to ICIs in both breast and lung cancer models.

Conclusions: AKR1B1 as a critical regulator of TAM-mediated immunosuppression and highlight its therapeutic potential to enhance the efficacy of ICIs.

Introduction: An adaptive immune response to cancer requires three main signals: antigen presentation and recognition ("signal 1"), costimulation ("signal 2"), and secreted immunostimulatory cytokines ("signal 3"). Expression of these signals in tumors via non-viral gene delivery represents a promising strategy to reprogram the tumor microenvironment (TME) and prime antitumor immunity.

Methods: We used modular polymeric poly(beta-amino ester)-based nanoparticles (NPs) to investigate codelivery of plasmids encoding signal 3s (interleukin (IL)-2, IL-12, IL-15, IL-23, IL-35, or granulocyte-macrophage colony-stimulating factor) and signal 2s (4-1BBL, CD80, CD86, or OX40L) to B16F10 melanoma tumors in vivo. Downstream immune responses and impact on the TME were assessed via flow cytometry and spatial proteomics using a 27-marker PhenoCycler panel.

Results: Ex vivo flow cytometry and PhenoCycler tissue analysis revealed that multiple signal 2/3 NP combinations led to decreased tumor growth, increased immune-cell infiltration, and skewing of adaptive and innate populations towards immunostimulatory phenotypes with increased CD8⁺ T-cell and M1 macrophage infiltration. Signal 2/3 NPs also drove antigen presentation on tumor and antigen-presenting cells (APCs) (macrophages, dendritic cells), and led to induction of major histocompatibility complex class I and class II on melanoma cells. Evaluation of putative biomarkers of treatment response to signal 2/3 NP delivery demonstrated that multiple markers of an inflamed TME correlated negatively with tumor growth, with antigen presentation induction highly correlated with tumor size reduction. Spatial analysis on top-performing NP formulations demonstrated that immune cell populations entered the TME via both the tumor-stroma interface and intratumoral vessels; CD8⁺ T cells and proinflammatory M1 macrophages were brought into proximity. Furthermore, top NP formulations increased the density of intratumoral CD8⁺-CD4⁺-proinflammatory APC triads, which have been identified as key structures for immunotherapy-mediated clearance of solid tumors.

Conclusions: These results demonstrate the utility of a modular NP design for systematic screening of signal 2/3 delivery to melanoma in vivo and highlight the benefit of in-depth profiling via spatial proteomics to evaluate local antitumor immune responses. The results provide insight into the mechanisms underpinning this therapeutic reprogramming strategy, emphasizing the relationship between signal 2/3 NPs and their ability to drive signal 1 for productive antitumor responses in vivo.

Background: Immune checkpoint inhibitors have transformed melanoma therapy but frequently cause immune-related adverse events (irAEs), including colitis, that limit treatment. Reliable biomarkers predicting toxicity remain lacking.

Methods: In this retrospective, multicenter study, we analyzed pretreatment serum samples from 331 patients with metastatic melanoma treated with anti-CTLA-4 (ipilimumab), anti-PD-1 (pembrolizumab or nivolumab), or combination ipilimumab/nivolumab. IgG autoantibody reactivity against 832 human protein antigens, including autoimmune targets, cytokines, tumor-associated antigens, and cancer pathway proteins, was profiled using multiplex bead-based arrays. Statistical analysis (Significance Analysis of Microarrays and Cox regression) identified autoantibody signatures associated with subsequent irAEs and immune-related colitis (ir-colitis).

Results: We detected 47 autoantibodies predictive of irAEs, with KRT7, RPLP2, UBE2Z, and GPHN emerging as the strongest markers. Anti-KRT7 and anti-GPHN were specifically predictive in patients receiving PD-1 monotherapy, whereas anti-RPLP2 was associated with irAEs in ipilimumab/nivolumab combination therapy. For ir-colitis, 38 autoantibodies were identified, with five (PIAS3, RPLP0, UBE2Z, KRT7, and SDCBP) showing consistent predictive value across treatment groups. Anti-PIAS3 and anti-RPLP0 increased ir-colitis risk, while anti-SDCBP conferred protection. Notably, predictive profiles differed between PD-1-based and CTLA-4-based regimens, underscoring divergent mechanisms of toxicity. Several autoantibodies predictive of irAEs or ir-colitis also correlated with clinical outcome. ATG4D, MAGEB4, and IL4R were associated with prolonged progression-free and overall survival, whereas FGFR1 predicted both reduced irAE risk and inferior survival, consistent with the link between heightened immune activation, toxicity, and therapeutic benefit.

Conclusions: This study, to our knowledge, is the largest pretreatment autoantibody screen in melanoma immunotherapy, demonstrates that serum autoantibody profiles can stratify patients at risk for irAEs and ir-colitis. The identified signatures connect tumor-related and immunity-related antigens, stress-response pathways, and autoimmune mechanisms. Pretreatment autoantibody profiling offers a promising biomarker-driven approach for individualizing risk assessment, improving patient selection, and guiding early intervention strategies to enhance the safety of immune checkpoint blockade in melanoma. Beyond toxicity prediction, our findings also suggest that specific autoantibodies may reflect underlying immune activation states linked to therapeutic response.