Tryptase expression as a prognostic marker in patients with resected gastric cancer

Role of mast cells activation in the tumor immune microenvironment and immunotherapy of cancers

The mast cell is an important cellular component that plays a crucial role in the crosstalk between innate and adaptive immune responses within the tumor microenvironment (TME). Recently, numerous studies have indicated that mast cells related to tumors play a dual role in regulating cancers, with conflicting results seemingly determined by the degranulation medium. As such, mast cells are an ignored but very promising potential target for cancer immunotherapy based on their immunomodulatory function. In this review, we present a comprehensive overview of the roles and mechanisms of mast cells in diverse cancer types. Firstly, we evaluated the infiltration density and location of mast cells on tumor progression. Secondly, mast cells are activated by the TME and subsequently release a range of inflammatory mediators, cytokines, chemokines, and lipid products that modulate their pro-or anti-tumor functions. Thirdly, activated mast cells engage in intercellular communication with other immune or stromal cells to modulate the immune status or promote tumor development. Finally, we deliberated on the clinical significance of targeting mast cells as a therapeutic approach to restrict tumor initiation and progression. Overall, our review aims to provide insights for future research on the role of mast cells in tumors and their potential as therapeutic targets for cancer treatment.

A robust six-gene prognostic signature based on two prognostic subtypes constructed by chromatin regulators is correlated with immunological features and therapeutic response in lung adenocarcinoma

Accumulating evidence has demonstrated that chromatin regulators (CRs) regulate immune cell infiltration and are correlated with prognoses of patients in some cancers. However, the immunological and prognostic roles of CRs in lung adenocarcinoma (LUAD) are still unclear. Here, we systematically revealed the correlations of CRs with immunological features and the survival in LUAD patients based on a cohort of gene expression datasets from the public TCGA and GEO databases and real RNA-seq data by an integrative analysis using a comprehensive bioinformatics method. Totals of 160 differentially expressed CRs (DECRs) were identified between LUAD and normal lung tissues, and two molecular prognostic subtypes (MPSs) were constructed and evaluated based on 27 prognostic DECRs using five independent datasets (p =0.016, <0.0001, =0.008, =0.00038 and =0.00055, respectively). Six differentially expressed genes (DEGs) (CENPK, ANGPTL4, CCL20, CPS1, GJB3, TPSB2) between two MPSs had the most important prognostic feature and a six-gene prognostic model was established. LUAD patients in the low-risk subgroup showed a higher overall survival (OS) rate than those in the high-risk subgroup in nine independent datasets (p <0.0001, =0.021, =0.016, =0.0099, <0.0001, =0.0045, <0.0001, =0.0038 and =0.00013, respectively). Six-gene prognostic signature had the highest concordance index of 0.673 compared with 19 reported prognostic signatures. The risk score was significantly correlated with immunological features and activities of oncogenic signaling pathways. LUAD patients in the low-risk subgroup benefited more from immunotherapy and were less sensitive to conventional chemotherapy agents. This study provides novel insights into the prognostic and immunological roles of CRs in LUAD.

Mast cells inhibit colorectal cancer development by inducing ER stress through secreting Cystatin C

Mast cells (MCs) are abundantly distributed in the human intestinal mucosa and submucosa. However, their roles and mechanisms in the development of colorectal cancer (CRC) are still unclear. In the present research, we found that the infiltration density of MCs in CRC tissues was positively correlated with improved patients' prognoses. Moreover, MCs suppressed the growth and induced the apoptosis of CRC cells in vitro and in vivo but had no effect on normal colonic epithelial cells. The present study revealed that MCs specifically induced endoplasmic reticulum stress (ERS) and activated the unfolded protein response (UPR) in CRC cells but not in normal cells, which led to the suppression of CRC development in vivo. Furthermore, we found that the secreted Cystatin C protein was the key factor for the MC-induced ERS in CRC cells. This work is of significance for uncovering the antitumor function of MCs in CRC progression and identifying the potential of CRC to respond to MC-targeted immunotherapy.

Intratumoral interleukin-9 delineates a distinct immunogenic class of gastric cancer patients with better prognosis and adjuvant chemotherapeutic response

Interleukin-9 (IL-9) is a T cell cytokine that is associated with inflammation and allergy, but the expression level of IL-9 in gastric cancer and its clinical significance are less well established. Our study aims to uncover the critical role of IL-9 in the progression of gastric cancer. Here, a total of 453 patients with gastric cancer undergoing curative resection were enrolled for immunohistochemical analyses, and Kaplan-Meier analysis was conducted to compare overall survival of patients in different subgroups. We further investigated the correlation between IL-9 expression and functional status of intratumoral CD8⁺ T cells by means of Flow cytometry. Moreover, in vitro study was preformed to further explore the influence of IL-9 on anti-tumor immunity. Results indicated that gastric cancer patients with high IL-9 expression showed improved overall survival and gained more benefit from 5-fluorouracil-based adjuvant chemotherapy (ACT). High IL-9 expression was associated with increased numbers and elevated function of intratumoral CD8⁺ T cells. In vitro study revealed that recombinant human IL-9 (rhIL-9) exhibit anti-tumor activity via enhancing the function of intratumoral CD8⁺ T cells. Moreover, we found rhIL-9 could augment the efficacy of Pembrolizumab in gastric cancer. In summary, these results suggest that IL-9 expression could act as an independent predictor for overall survival and ACT response and enhancing IL-9 signaling might represent an important therapeutic strategy in gastric cancer.

Latency-associated Peptide Identifies Immunoevasive Subtype Gastric Cancer With Poor Prognosis and Inferior Chemotherapeutic Responsiveness

OBJECTIVE

To examine the clinical significance of LAP to predict survival outcomes and chemotherapeutic responsiveness in gastric cancer.

BACKGROUND

LAP has been shown to possess significant immunoregulatory roles in several malignancies. However, the role and clinical significance of LAP in gastric cancer still remains unknown.

METHODS

Four hundred and fifty-six tumor tissue microarray specimens, 80 fresh tumor tissue samples of gastric cancer patients from Zhongshan Hospital, Fudan University and transcriptomic and clinical data of 328 gastric cancer patients from the Cancer Genome Atlas were analyzed. LAP expression and immune contexture were examined by immunohistochemistry, CIBERSORT, and flow cytometry. Clinical outcomes of patient subgroups were compared by Kaplan-Meier curves, Cox model and interaction test.

RESULTS

High LAP expression predicted poor overall survival (P < 0.001, P < 0.001, and P = 0.022) and inferior therapeutic responsiveness to fluorouracil-based adjuvant chemotherapy (P = 0.008 for interaction) in gastric cancer. LAP was associated with immunoevasive tumor microenvironment featured by dysfunctional CD8 T cells infiltration (P < 0.001). The LAP-associated dysfunctional CD8 T cells had an exhausted phenotype with decreased effector molecules such as interferon-γ, granzyme B, and perforin, but also elevated programmed cell death protein-1, which resulted in poor prognosis and inferior therapeutic responsiveness.

CONCLUSIONS

This study revealed that LAP could identify immunoevasive subtype gastric cancer, indicating LAP might be a potential immunotherapeutic target and facilitate patient counseling on individualized adjuvant therapy and follow-up scheduling in gastric cancer.

High infiltration of mast cells is associated with improved response to adjuvant chemotherapy in gallbladder cancer

Recent studies have reported that tumor‐infiltrating mast cells (TIM) play an important role in tumor regression, but the effect of TIM in gallbladder cancer (GBC) remains unclear. The present study aims to investigate the prognostic value of TIM in GBC patients and its responsiveness to gemcitabine‐based adjuvant chemotherapy (ACT). A total of 298 GBC patients from Zhongshan Hospital were recruited for this study. TIM infiltration was measured by immunohistochemical staining. Accumulation of TIM is significantly associated with prolonged overall survival in GBC patients. The benefit from gemcitabine‐based ACT was superior among patients with high infiltration of TIM with GBC. Multivariate analysis identified TIM infiltration as an independent prognostic factor for overall survival. A heatmap showed that TIM‐activated gene signatures were positively correlated with CD8+ T cells' gene signatures. Gene set enrichment analysis (GSEA) suggested that TIM was related to multiple T cell‐related processes and signaling pathways, including the interferon gamma signaling pathway and the leukocyte migration signaling pathway. It was confirmed that CD8+ T cell infiltration was positively correlated with high TIM infiltration in tissue microarray (TMA), suggesting that TIM infiltration was linked to the immune surveillance in GBC. TIM can be used as an independent prognostic factor and a predictor of therapeutic response of gemcitabine‐based ACT in GBC patients, which may mediate immune surveillance by recruiting and activating CD8+ T cells in GBC.

Mast Cells in the Tumor Microenvironment

Mast cells are tissue-resident, innate immune cells that play a key role in the inflammatory response and tissue homeostasis. Mast cells accumulate in the tumor stroma of different human cancer types, and increased mast cell density has been associated to either good or poor prognosis, depending on the tumor type and stage. Mast cells play a multifaceted role in the tumor microenvironment by modulating various events of tumor biology, such as cell proliferation and survival, angiogenesis, invasiveness, and metastasis. Moreover, tumor-associated mast cells have the potential to shape the tumor microenvironment by establishing crosstalk with other tumor-infiltrating cells. This chapter reviews the current understanding of the role of mast cells in the tumor microenvironment. These cells have received much less attention than other tumor-associated immune cells but are now recognized as critical components of the tumor microenvironment and could hold promise as a potential target to improve cancer immunotherapy.

Clinical and transcriptional signatures of human CD204 reveal an applicable marker for the protumor phenotype of tumor-associated macrophages in breast cancer

Background: Tumor-associated macrophages in human breast cancer are poorly understood. Specific tumor-associated macrophage-related molecular mechanisms among different intrinsic molecular subtypes remain unclear. Here, we have identified and explored the roles of the tumor-associated macrophages novel marker: CD204 in different subtypes of breast cancer.

Results: CD204 was upregulated in four subtypes of breast cancer, and this was associated with poor survival outcomes. CD204 could promote tumor cell proliferation, migration, and invasion and was involved in immune system-related pathways among all subtypes. Special pathways in each subtype were also found. High CD204 mRNA expressions were associated with high proportions of protumor immune cell populations, and most immunoinhibitors positive correlated with CD204 expression in all subtypes.

Conclusions: These findings contribute to a better understanding and managing the protumor phenotype of tumor-associated macrophages in different subtypes of breast cancer.

Methods: The expression of CD204 and its clinical outcome were analyzed. The roles of CD204 in the regulation of tumor cell proliferation, migration, and invasion were studied. Potential pathways influenced by CD204 were displayed. Immune cell infiltration in different CD204 mRNA expression status and correlations between CD204 and immunoinhibitors were also analyzed.

Tumour-associated macrophages-derived CXCL8 determines immune evasion through autonomous PD-L1 expression in gastric cancer

OBJECTIVE

Our previous studies have identified CXCL8 as the crucial chemokine responsible for gastric cancer metastasis mediated by loss of RACK1. However, the regulatory effect of CXCL8 on immune surveillance in gastric cancer remains obscure.

DESIGN

Flow cytometry analyses were performed to examine major source of CXCL8 and phenotypes of immune cells in fresh tumour tissues from 76 patients with gastric cancer. Real-time PCR was performed to analyse CXCL8 mRNA level in gastric cancer tissues. For immunohistochemical analyses, a total of 420 patients with gastric cancer undergoing curative resection were enrolled. In vitro culture of fresh tumour tissue was performed to evaluate the potential therapeutic effect of blocking CXCL8 pathway in gastric cancer.

RESULTS

Increased level of CXCL8 indicates poor clinical outcome and tumour progression in patients with gastric cancer. In gastric cancer tissues, CXCL8 is predominantly secreted by macrophages and colony stimulating factor 2 (CSF-2) facilitates macrophage-derived CXCL8 secretion. High level of CXCL8 is associated with decreased CD8⁺ T cells infiltration and Ki67⁺ CD8⁺ T cells proportion. Moreover, CXCL8 also inhibits CD8⁺ T cells function by inducing the expression of PD-L1 on macrophages. Finally, we show that a small-molecule CXCR2 inhibitor, reparixin, drives the decreased programmed death-ligand 1 (PD-L1⁺) macrophages and promotes antitumour immunity. Accordingly, high levels of CXCL8⁺ macrophages are positively correlated with poor prognosis in patients with gastric cancer.

CONCLUSIONS

CXCL8 is predominantly secreted by macrophages and contributes to the immunosuppressive microenvironment by inducing PD-L1⁺ macrophages in gastric cancer. CXCL8 inhibitors may drive antitumour response, providing potential therapeutic effects for patients with gastric cancer.

Increased intratumoral mast cells foster immune suppression and gastric cancer progression through TNF-α-PD-L1 pathway

Background

Mast cells are prominent components of solid tumors and exhibit distinct phenotypes in different tumor microenvironments. However, the nature, regulation, function, and clinical relevance of mast cells in human gastric cancer (GC) are presently unknown.

Methods

Flow cytometry analyses were performed to examine level and phenotype of mast cells in samples from 114 patients with GC. Multivariate analysis of prognostic factors for overall survival was performed using the Cox proportional hazards model. Kaplan-Meier plots for patient survival were performed using the log-rank test. Mast cells, T cells and tumor cells were isolated or generated, stimulated and/or cultured for in vitro and in vivo function assays.

Results

Patients with GC showed a significantly higher mast cell infiltration in tumors. Mast cell levels increased with tumor progression and independently predicted reduced overall survival. These tumor-infiltrating mast cells accumulated in tumors by CXCL12-CXCR4 chemotaxis. Intratumoral mast cells expressed higher immunosuppressive molecule programmed death-ligand 1 (PD-L1), and mast cells induced by tumors strongly express PD-L1 proteins in both time-dependent and dose-dependent manners. Significant correlations were found between the levels of PD-L1⁺ mast cells and pro-inflammatory cytokine TNF-α in GC tumors, and tumor-derived TNF-α activated NF-κB signaling pathway to induce mast cell expression of PD-L1. The tumor-infiltrating and tumor-conditioned mast cells effectively suppressed normal T-cell immunity through PD-L1 in vitro, and tumor-conditioned mast cells contributed to the suppression of T-cell immunity and the growth of human GC tumors in vivo; the effect could be reversed by blocking PD-L1 on these mast cells.

Conclusion

Thus, our results illuminate novel immunosuppressive and protumorigenic roles of mast cells in GC, and also present a novel mechanism in which PD-L1 expressing mast cells link the proinflammatory response to immune tolerance in the GC tumor milieu.

Electronic supplementary material

The online version of this article (10.1186/s40425-019-0530-3) contains supplementary material, which is available to authorized users.

Intratumoral IL17-producing cells infiltration correlate with antitumor immune contexture and improved response to adjuvant chemotherapy in gastric cancer

BACKGROUND

Tumor IL17-producing (IL17A+) cells infiltration has different prognostic values among various cancers. The objective of this study was to assess the effect of IL17A+ cells in gastric cancer.

PATIENTS AND METHODS

The study included two patient cohorts, the Cancer Genome Atlas cohort (TCGA, n = 351) and the Zhongshan Hospital cohort (ZSHC, n = 458). The TCGA and ZSHC were used for mRNA-related and cells infiltration-related analyses, respectively. The roles of IL17A mRNA and IL17A+ cells in overall survival (OS), response to adjuvant chemotherapy (ACT), and immune contexture were evaluated. Another independent cohort was included to identify the correlation between mRNA of IL17A and IL17A+ cells infiltration (the preliminary Zhongshan Hospital cohort, PZSHC, n = 21).

RESULTS

The infiltration of IL17A+ cells was positively correlated with the expression of IL17A mRNA (Spearman's ρ = 0.811; P < 0.001). High IL17A mRNA expression and intratumoral IL17A+ cells were correlated with improved OS and remained to be significant after adjusted for confounders. Patients with TNM II/III disease whose tumor present higher intratumoral IL17A+ cells or lower peritumoral IL17A+ cells can benefit more from ACT. Elevated IL17A mRNA expression and increased intratumoral IL17A+ cells infiltration was associated with more antitumor mast cells and nature killer cells infiltration and less pro-tumor M2 macrophages infiltration. High IL17A mRNA expression represented a Th17 cells signature and immune response process and was correlated with increased cytotoxic GZMA, GZMB, IFNG, PRF1, and TNFSF11 expression.

CONCLUSIONS

IL17A mRNA expression and intratumoral IL17A+ cells infiltration were correlated with antitumor immune contexture. IL17A+ cells infiltration could be used as an independent prognostic biomarker for OS and predictive biomarker for superior response to ACT, and further prospective validation needs to be conducted.

Degranulation of mast cells induced by gastric cancer-derived adrenomedullin prompts gastric cancer progression

Mast cells are prominent components of solid tumors and exhibit distinct phenotypes in different tumor microenvironments. However, their precise mechanism of communication in gastric cancer remains largely unclear. Here, we found that patients with GC showed a significantly higher mast cell infiltration in tumors. Mast cell levels increased with tumor progression and independently predicted reduced overall survival. Tumor-derived adrenomedullin (ADM) induced mast cell degranulation via PI3K-AKT signaling pathway, which effectively promoted the proliferation and inhibited the apoptosis of GC cells in vitro and contributed to the growth and progression of GC tumors in vivo, and the effect could be reversed by blocking interleukin (IL)-17A production from these mast cells. Our results illuminate a novel protumorigenic role and associated mechanism of mast cells in GC, and also provide functional evidence for these mast cells to prevent, and to treat this immunopathogenesis feature of GC.

Review of recent efforts to discover biomarkers for early detection, monitoring, prognosis, and prediction of treatment responses of patients with gastric cancer

Gastric cancer (GC) is the leading cause of cancer-related death worldwide. Despite recent advances in diagnosis and therapy, the prognosis of patients with GC is poor. Many patients have inoperable disease upon diagnosis or experience recurrent disease after curative gastrectomy. Unfortunately, tumor markers for GC, such as serum carcinoembryonic antigen and carbohydrate antigen 19-9, lack sufficient sensitivity and specificity. Therefore, effective biomarkers are required to detect early GC and to predict tumor recurrence and chemosensitivity. Areas covered: Here we aimed to review recent developments in techniques that improve the detection of aberrant expression of GC-associated molecules, including protein coding genes, microRNAs, long noncoding RNAs, and methylated promoter DNAs. Expert commentary: Detection of genetic and epigenetic alterations in gastric tissue or in the circulation will likely improve the diagnosis and management of GC to achieve significantly improved outcomes.