Guoying Zhou

Background: The immunosuppressive tumor microenvironment in hepatocellular carcinoma (HCC) limits the efficacy of current immunotherapies. The interplay between the emerging inhibitory receptor NKG2A and its activating counterpart NKG2C, both binding HLA-E, and its interaction with the PD-1-PD-L1 pathway in cancer remains unclear. This study aims to delineate the functional network formed by these pathways in shaping the immunosuppressive landscape of HCC. Methods: We analyzed public databases and performed immunohistochemistry on HCC tissues to assess HLA-E expression and prognostic relevance. Tumor-infiltrating lymphocytes from patient samples were examined by flow cytometry to evaluate the functional impact of NKG2A, NKG2C, and PD-1 expression on T and NK cells. Single-cell RNA and T cell receptor (TCR) sequencing were employed to characterize immune subset heterogeneity. Functional assays and mouse models were used to evaluate the effects of NKG2A and PD-1 blockade. Results: In the absence of CD8 ⁺ T cell infiltration, elevated HLA-E expression in HCC tissue correlated with poorer overall survival in non-immunotherapy-treated patients. Conversely, in the presence of CD8 ⁺ T cells, high HLA-E expression was linked to an inflammatory tumor microenvironment characterized by IFN-γ-producing T cells, and increased major histocompatibility complex I, which was associated with improved patient response to immunotherapy. Tumor-infiltrating CD8 ⁺ T and NK cells from HCC patients upregulated NKG2A, conferring tissue-resident memory and tumor-reactive characteristics while simultaneously impairing cytotoxic function. Single-cell RNA and TCR sequencing revealed differential expression patterns of NKG2A, NKG2C, and PD-1 in different T and NK cell subsets, with NKG2A ⁺ PD-1 ⁺ T cells relevant to antigen-specific clonal expansion. Mechanistically, the inhibitory effect mediated by the NKG2A-HLA-E axis contributed more prominently than the stimulatory role of the NKG2C-HLA-E axis in suppressing antitumor immunity. Furthermore, the NKG2A-HLA-E axis acted cooperatively with the PD-1-PD-L1 axis to promote CD8 ⁺ T cell dysfunction. Combined blockade of NKG2A and PD-1 enhanced the cytotoxic activity of tumor-infiltrating CD8 ⁺ T and NK cells, resulting in potent tumor eradication in vitro and in vivo, outperforming single-agent treatments. Conclusions: Our findings identify the NKG2A-HLA-E axis as an important immunoregulatory pathway associated with immune suppression in HCC and provide a rationale for further evaluation of combined NKG2A and PD-1 blockade strategies.

The roles of NKG2A-HLA-E and TIM3-galectin 9 immune checkpoint pathways in pancreatic ductal adenocarcinoma (PDAC) progression remain incompletely characterized. This study investigates their contributions to PDAC and therapeutic potential. The expressions of ligands HLA-E and galectin 9 and receptors NKG2A and TIM3 were analyzed through bioinformatics, immunohistochemistry, and flow cytometry. Effects of HLA-E and galectin 9 overexpression on pancreatic epithelial cells were assessed by Transwell, wound healing, and CCK-8 assays. Ligand-receptor interactions and their impact on lymphocyte function were examined by multiplex immunofluorescence, single-cell RNA-sequencing, and functional assays. The expression of ligands HLA-E and galectin 9 was elevated in PDAC cancer tissues compared with both normal tissues and benign lesions. The overexpression of HLA-E enhanced the migratory and invasive ability of pancreatic epithelial cells. Moreover, the high expression of HLA-E and galectin 9 correlated with worse overall survival in PDAC patients. Mechanistically, increased NKG2A expression in both tumor stroma and parenchyma was associated with impaired function of tumor-infiltrating T cells and NK cells. Spatial analyses further revealed colocalization of NKG2A⁺ T cells with high HLA-E-expressing tumor regions, indicating an active and localized immunosuppressive circuit. Single-cell profiling showed that NKG2A⁺ and TIM3⁺ tumor-infiltrating T cells exhibited exhausted signatures, particularly when co-expressing PD-1. Importantly, dual blockade of NKG2A or TIM3 with PD-1 enhanced the anti-tumor response of CD8⁺ and CD4⁺ T cells, mediated by SHP-1 inhibition and ERK activation. This study identifies NKG2A-HLA-E and TIM3-galectin 9 pathways as key mechanisms in PDAC progression and immune inhibition and provides a mechanistic rationale for combining their blockade with PD-1-PD-L1 blockade as a potential therapeutic strategy.

Background: Detecting low-frequency mutations is crucial for predicting prognosis and monitoring minimal residual disease (MRD) in acute myeloid leukemia (AML). However, the presence of abundant wild-type sequences hinders the detection of rare mutant alleles. We present a highly sensitive method called ACE (Amplifying–Cleaving–Enriching) to selectively enrich mutant sequences. Methods: ACE includes three steps: (1) initial PCR amplification using biotin-labeled primers, (2) cleavage of wild-type sequences with a specific restriction enzyme, and (3) enrichment of undigested mutant alleles via streptavidin-labeled magnetic beads. Results: Using two rounds of ACE, we achieved over 80,000-fold enrichment of mutant sequences carrying FLT3-TKD, enabling the detection of mutant alleles at levels as low as 0.0001% in AML patient blood samples. Additionally, the ACE method can be adapted to nearly any driver mutation by introducing wild-type-specific restriction sites through PCR with mismatched primers, which has been validated in the IDH1 mutation. Furthermore, the ACE method can be flexibly integrated into conventional detection techniques including Sanger sequencing, quantitative real-time PCR, allele-specific PCR, and even with advanced techniques like droplet digital PCR. Conclusions: ACE significantly enhances the sensitivity of existing techniques for rare mutation detection and holds potential for broad clinical applications.

Immune checkpoint blockade, which enhances the reactivity of T cells to eliminate cancer cells, has emerged as a potent strategy in cancer therapy. Besides T cells, natural killer (NK) cells also play an indispensable role in tumor surveillance and destruction. NK Group 2 family of receptor A (NKG2A), an emerging co-inhibitory immune checkpoint expressed on both NK cells and T cells, mediates inhibitory signal via interaction with its ligand human leukocyte antigen-E (HLA-E), thereby attenuating the effector and cytotoxic functions of NK cells and T cells. Developing antibodies to block NKG2A, holds promise in restoring the antitumor cytotoxicity of NK cells and T cells. In this review, we delve into the expression and functional significance of NKG2A and HLA-E, elucidating how the NKG2A-HLA-E axis contributes to tumor immune escape via signal transduction mechanisms. Furthermore, we provide an overview of clinical trials investigating NKG2A blockade, either as monotherapy or in combination with other therapeutic antibodies, highlighting the responses of the immune system and the clinical benefits for patients. We pay special attention to additional immune co-signaling molecules that serve as potential targets on both NK cells and T cells, aiming to evoke more robust immune responses against cancer. This review offers an in-depth exploration of the NKG2A-HLA-E pathway as a pivotal checkpoint in the anti-tumor responses, paving the way for new immunotherapeutic strategies to improve cancer patient outcomes.

Hepato-pancreato-biliary (HPB) cancer is a serious category of cancer including tumors originating in the liver, pancreas, gallbladder and biliary ducts. It is limited by two-dimensional (2D) cell culture models for studying its complicated tumor microenvironment including diverse contents and dynamic nature. Recently developed three-dimensional (3D) bioprinting is a state-of-the-art technology for fabrication of biological constructs through layer-by-layer deposition of bioinks in a spatially defined manner, which is computer-aided and designed to generate viable 3D constructs. 3D bioprinting has the potential to more closely recapitulate the tumor microenvironment, dynamic and complex cell-cell and cell-matrix interactions compared to the current methods, which benefits from its precise definition of positioning of various cell types and perfusing network in a high-throughput manner. In this review, we introduce and compare multiple types of 3D bioprinting methodologies for HPB cancer and other digestive tumors. We discuss the progress and application of 3D bioprinting in HPB and gastrointestinal cancers, focusing on tumor model manufacturing. We also highlight the current challenges regarding clinical translation of 3D bioprinting and bioinks in the field of digestive tumor research. Finally, we suggest valuable perspectives for this advanced technology, including combination of 3D bioprinting with microfluidics and application of 3D bioprinting in the field of tumor immunology.

Background: Immunotherapy with immune checkpoint inhibitors (ICIs) is being explored to improve cholangiocarcinoma (CCA) therapy. However, it remains difficult to predict which ICI will be effective for individual patients. Therefore, the aim of this study is to develop a co-culture method with patient-derived CCA organoids and immune cells, which could represent anti-cancer immunity in vitro. Methods: CCA organoids were co-cultured with peripheral blood mononuclear cells or T cells. Flow cytometry, time-lapse confocal imaging for apoptosis, and quantification of cytokeratin 19 fragment (CYFRA) release were applied to analyse organoid and immune cell behaviour. CCA organoids were also cultured in immune cell-conditioned media to analyse the effect of soluble factors. Results: The co-culture system demonstrated an effective anti-tumour organoid immune response by a decrease in live organoid cells and an increase in apoptosis and CYFRA release. Interpatient heterogeneity was observed. The cytotoxic effects could be mediated by direct cell–cell contact and by release of soluble factors, although soluble factors only decreased viability in one organoid line. Conclusions: In this proof-of-concept study, a novel CCA organoid and immune cell co-culture method was established. This can be the first step towards personalised immunotherapy for CCA by predicting which ICIs are most effective for individual patients.

Liver cancer is one of the most prevalent cancers, and the third most common cause of cancer-related mortality worldwide. The therapeutic options for the main types of primary liver cancer—hepatocellular carcinoma (HCC) and cholangiocarcinoma (CCA)—are very limited. HCC and CCA are immunogenic cancers, but effective immune-mediated tumour control is prevented by their immunosuppressive tumour microenvironment. Despite the critical involvement of key co-inhibitory immune checkpoint interactions in immunosuppression in liver cancer, only a minority of patients with HCC respond to monotherapy using approved checkpoint inhibitor antibodies. To develop effective (combinatorial) therapeutic immune checkpoint strategies for liver cancer, in-depth knowledge of the different mechanisms that contribute to intratumoral immunosuppression is needed. Here, we review the co-inhibitory pathways that are known to suppress intratumoral T cells in HCC and CCA. We provide a detailed description of insights from preclinical studies in cellular crosstalk within the tumour microenvironment that results in interactions between co-inhibitory receptors on different T-cell subsets and their ligands on other cell types, including tumour cells. We suggest alternative immune checkpoints as promising targets, and draw attention to the possibility of combined targeting of co-inhibitory and co-stimulatory pathways to abrogate immunosuppression.

High recurrence rates after resection of hepatocellular carcinoma (HCC) with curative intent impair clinical outcomes of HCC. Cancer/testis antigens (CTAs) are suitable targets for cancer immunotherapy if selectively expressed in tumor cells. The aims were to identify CTAs that are frequently and selectively expressed in HCC-tumors, and to investigate whether CTAs could serve as biomarkers for occult metastasis. Tumor and paired tumor-free liver (TFL) tissues of HCC-patients and healthy tissues were assessed for mRNA expression of 49 CTAs by RT-qPCR and protein expression of five CTAs by immunohistochemistry. Twelve CTA-mRNAs were expressed in ≥10% of HCC-tumors and not in healthy tissues except testis. In tumors, mRNA and protein of ≥ 1 CTA was expressed in 78% and 71% of HCC-patients, respectively. In TFL, CTA mRNA and protein was found in 45% and 30% of HCC-patients, respectively. Interestingly, CTA-expression in TFL was an independent negative prognostic factor for post-resection HCC-recurrence and survival. We established a panel of 12 testis-restricted CTAs expressed in tumors of most HCC-patients. The increased risk of HCC-recurrence in patients with CTA expression in TFL, suggests that CTA-expressing (pre-)malignant cells may be a source of HCC-recurrence, reflecting the relevance of targeting these to prevent HCC-recurrence.

Metabolic reprogramming universally occurs in cancer. Mitochondria act as the hubs of bioenergetics and metabolism. The morphodynamics of mitochondria, comprised of fusion and fission processes, are closely associated with mitochondrial functions and are often dysregulated in cancer. In this study, we aim to investigate the mitochondrial morphodynamics and its functional consequences in human liver cancer. We observed excessive activation of mitochondrial fusion in tumor tissues from hepatocellular carcinoma (HCC) patients and in vitro cultured tumor organoids from cholangiocarcinoma (CCA). The knockdown of the fusion regulator genes, OPA1 (Optic atrophy 1) or MFN1 (Mitofusin 1), inhibited the fusion process in HCC cell lines and CCA tumor organoids. This resulted in inhibition of cell growth in vitro and tumor formation in vivo, after tumor cell engraftment in mice. This inhibitory effect is associated with the induction of cell apoptosis, but not related to cell cycle arrest. Genome-wide transcriptomic profiling revealed that the inhibition of fusion predominately affected cellular metabolic pathways. This was further confirmed by the blocking of mitochondrial fusion which attenuated oxygen consumption and cellular ATP production of tumor cells. In conclusion, increased mitochondrial fusion in liver cancer alters metabolism and fuels tumor cell growth.