Poorly cohesive gastric cancer with increased epithelial‑mesenchymal transition is associated with a poor prognosis

The present study examined the surgical outcome and prognosis of patients with poorly cohesive carcinoma (PCC), and characterized the molecular pathological factors, epithelial-mesenchymal transition (EMT) and interstitial signals of the disease. A total of 281 patients who underwent gastric cancer (GC) surgery between April 2015 and August 2020 were included. Furthermore, tissue samples from another 197 patients with GC who underwent surgery between 1999 and 2003 were assessed using a tissue microarray. Preoperatively treated cases and endoscopic submucosal dissection cases were excluded, and multiple blocks containing the invasion region were collected for tissue microarray. For tissue microarray analysis, the clinicopathological factors of protein wnt3a (wnt3a), leucine-rich repeat-containing G-protein coupled receptor 5, transforming growth factor-β-induced, phosphorylated serine/threonine-protein kinase mTOR and E-cadherin expression were collected as EMT markers. The results of the surgical case evaluation and tissue microarray indicated that PCC was more common in younger patients and women, as the ratio of women to men was higher in the PCC group compared with that in the non-PCC group. However, none of the results revealed that the prognosis was worse in all patients with PCC compared with the non-PCC group. Furthermore, in the tissue microarray study, PCC samples exhibited significantly decreased expression of the cell adhesion molecule E-cadherin, suggesting enhanced EMT, which activates wnt3a signaling. PCC with increased EMT was significantly associated with a poor prognosis.

Periostin in Cancer-Associated Fibroblasts Promotes Esophageal Squamous Cell Carcinoma Progression by Enhancing Cancer and Stromal Cell Migration

Cancer-associated fibroblasts (CAFs) in the tumor microenvironment are involved in the progression of various cancers, including esophageal squamous cell carcinoma (ESCC). CAF-like cells were generated through direct co-culture of human bone marrow-derived mesenchymal stem cells, one of CAF origins, with ESCC cells. Periostin (POSTN) was found to be highly expressed in CAF-like cells. After direct co-culture, ESCC cells showed increased malignant phenotypes, such as survival, growth, and migration, as well as increased phosphorylation of Akt and extracellular signal-regulated kinase (Erk). Recombinant human POSTN activated Akt and Erk signaling pathways in ESCC cells, enhancing survival and migration. The suppression of POSTN in CAF-like cells by siRNA during direct co-culture also suppressed enhanced survival and migration in ESCC cells. In ESCC cells, knockdown of POSTN receptor integrin β4 inhibited Akt and Erk phosphorylation, and survival and migration increased by POSTN. POSTN also enhanced mesenchymal stem cell and macrophage migration and endowed macrophages with tumor-associated macrophage-like properties. Immunohistochemistry showed that high POSTN expression in the cancer stroma was significantly associated with tumor invasion depth, lymphatic and blood vessel invasion, higher pathologic stage, CAF marker expression, and infiltrating tumor-associated macrophage numbers. Moreover, patients with ESCC with high POSTN expression exhibited poor postoperative outcomes. Thus, CAF-secreted POSTN contributed to tumor microenvironment development. These results indicate that POSTN may be a novel therapeutic target for ESCC.

Identification of potential LncRNAs as papillary thyroid carcinoma biomarkers based on integrated bioinformatics analysis using TCGA and RNA sequencing data

The roles and mechanisms of long non-coding RNAs (lncRNAs) in papillary thyroid cancer (PTC) remain elusive. We obtained RNA sequencing (RNA-seq) data of surgical PTC specimens from patients with thyroid cancer (THCA; n = 20) and identified differentially expressed genes (DEGs) between cancer and cancer-adjacent tissue samples. We identified 2309 DEGs (1372 significantly upregulated and 937 significantly downregulated). We performed Gene Ontology, Kyoto Encyclopedia of Genes and Genomes, gene set enrichment, and protein-protein interaction network analyses and screened for hub lncRNAs. Using the same methods, we analyzed the RNA-seq data from THCA dataset in The Cancer Genome Atlas (TCGA) database to identify differentially expressed lncRNAs. We identified 15 key differentially expressed lncRNAs and pathways that were closely related to PTC. Subsequently, by intersecting the differentially expressed lncRNAs with hub lncRNAs, we identified LINC02407 as the key lncRNA. Assessment of the associated clinical characteristics and prognostic correlations revealed a close correlation between LINC02407 expression and N stage of patients. Furthermore, receiver operating characteristic curve analysis showed that LINC02407 could better distinguish between cancerous and cancer-adjacent tissues in THCA patients. In conclusion, our findings suggest that LINC02407 is a potential biomarker for PTC diagnosis and the prediction of lymph node metastasis.

PCLassoLog: A protein complex-based, group Lasso-logistic model for cancer classification and risk protein complex discovery

Risk gene identification has attracted much attention in the past two decades. Since most genes need to be translated into proteins and cooperate with other proteins to form protein complexes to carry out cellular functions, which significantly extends the functional diversity of individual proteins, revealing the molecular mechanism of cancer from a comprehensive perspective needs to shift from identifying individual risk genes toward identifying risk protein complexes. Here, we embed protein complexes into the regularized learning framework and propose a protein complex-based, group Lasso-logistic model (PCLassoLog) to discover risk protein complexes. Experiments on deep proteomic data of two cancer types show that PCLassoLog yields superior predictive performance on independent datasets. More importantly, PCLassoLog identifies risk protein complexes that not only contain individual risk proteins but also incorporate close partners that synergize with them. Furthermore, selection probabilities are calculated and two other protein complex-based models are proposed to complement PCLassoLog in identifying reliable risk protein complexes. Based on PCLassoLog, a pan-cancer analysis is performed to identify risk protein complexes in 12 cancer types. Finally, PCLassoLog is used to discover risk protein complexes associated with gene mutation. We implement all protein complex-based models as an R package PCLassoReg, which may serve as an effective tool to discover risk protein complexes in various contexts.

Ginsenoside Rh1 regulates gastric cancer cell biological behaviours and transplanted tumour growth in nude mice via the TGF-β/Smad pathway

Gastric cancer (GC) is one of the most prevalent malignancies of the digestive tract. Ginsenoside Rh1 was reported to exert effects on GC. The current study set out to explore the mechanism underlying Ginsenoside Rh1 effects on GC. With oxaliplatin (OXA) serving as the positive control, human GC cells AGS were treated with 0, 10, 25, 50, 74, or 100 μM of ginsenoside Rh1 for 48 h. Proliferation, migration, invasion, and apoptosis were subsequently assessed by means of MTT, scratch test, Transwell, and TUNEL, respectively. AGS cells were further jointly treated with Rh1 and the TGF-β/Smad pathway activator Kartogenin, followed by detection of TGF-β/Smad pathway effects on AGS biological behaviours. Moreover, TGF-β/Smad pathway activation was detected with a Western blot assay. Furthermore, xenograft tumour models were established and tumour growth was recorded. Ki-67 expression patterns and apoptosis were detected with immunohistochemistry and TUNEL, respectively. In vitro, Ginsenoside Rh1 repressed AGS cell proliferation, migration, and invasion, and further promoted apoptosis, with a concentration of 50 μM Rh1 exerting the equivalent effects as OXA. In vivo, Ginsenoside Rh1 inhibited GC proliferation and induced tumour cell apoptosis. Mechanistically, Ginsenoside Rh1 reduced TGF-β1 and TGF-β2 levels and Smad2 and Smad3 phosphorylation levels. Collectively, our findings highlighted that ginsenoside Rh1 inhibited GC cell growth and tumour growth in xenograft tumour models via inhibition of the TGF-β/Smad pathway.

Pan-Cancer Analysis of the Associations of TGFBI Expression With Prognosis and Immune Characteristics

Transforming growth factor-beta-induced (TGFBI) protein has important roles in tumor growth, metastasis, and immunity. However, there is currently no pan-cancer evidence regarding TGFBI. In this study, we conducted a pan-cancer analysis of TGFBI mRNA and protein expression and prognoses of various cancer types using public databases. We also investigated the associations of TGFBI expression with tumor microenvironment (TME) components, immune cell infiltration, tumor mutational burden (TMB), and microsatellite instability (MSI), along with the TGFBI genetic alteration types. The results showed that TGFBI expression varied among different cancer types, and it was positively or negatively related to prognosis in various cancers. TGFBI expression was also significantly correlated with TME components, TMB, MSI, immune cell infiltration, and immunoinhibitory and immunostimulatory gene subsets. These findings indicate that TGFBI participates in various immune responses and it may function as a prognostic marker in various cancers. The findings may be useful for developing immunotherapies that target TGFBI.

The role of transforming growth factor β in upper gastrointestinal cancers: A systematic review

Esophageal and gastric malignancies are associated with poor prognosis, in part due to development of recurrences or metastases after curative treatment. The transforming growth factor β (TGF-β) pathway might play a role in the development of treatment resistance. In this systematic review, we provide an overview of preclinical studies investigating the role of TGF-β in esophageal and gastric malignancies. We systematically searched MEDLINE/PubMed and EMBASE for eligible preclinical studies describing the effect of TGF-β or TGF-β inhibition on hallmarks of cancer, such as proliferation, migration, invasion, angiogenesis and immune evasion. In total, 2107 records were screened and 45 articles were included, using mouse models and 45 different cell lines. TGF-β failed to induce apoptosis in twelve of sixteen tested cell lines. TGF-β could either decrease (five cell lines) or increase proliferation (seven cell lines) in gastric cancer cells, but had no effect in esophageal cancer cells. In all esophageal and all but two gastric cancer cell lines, TGF-β increased migratory, adhesive and invasive capacities. In vivo studies showed increased metastasis in response to TGF-β treatment. Additionally, TGF-β was shown to induce vascular endothelial growth factor production and differentiation of cancer-associated fibroblasts and regulatory T-cells. In conclusion, we found that TGF-β enhances hallmarks of cancer in most gastric and esophageal cancer cell lines, but not in all. Therefore, targeting the TGF-β pathway could be an attractive strategy in patients with gastric or esophageal cancer, but additional clinical trials are needed to define patient groups who would benefit most.

Eugenol and capsaicin exhibit anti-metastatic activity via modulating TGF-β signaling in gastric carcinoma

The transforming growth factor-β (TGF-β) signaling is considered to be a key player in gastric cancer metastasis, and the inhibition of the TGF-β/SMAD4 signaling pathway may be a novel strategy for therapeutic interventions in cancer. Here, the anti-metastatic activity of two phytochemicals, eugenol and capsaicin, has been studied, and their potential to antagonize TGF-β has been investigated in gastric cancer cells. Both the phytochemicals exhibited anti-metastatic activity by inhibiting the TGF-β signaling pathway independent of P21 or P53, with capsaicin proving to be more potent than eugenol. However, unlike eugenol, the inhibitory effect of capsaicin on the TGF-β signaling pathway and metastasis was found to be dependent on SMAD4, which was validated in SMAD4-knocked down AGS cell and SMAD4-null SW620 cell line. Furthermore, the use of recombinant TGF-β and TGF-β receptor inhibitor LY2109761 confirmed that the anti-metastatic activity of eugenol is partially and that of capsaicin is principally mediated through the TGF-β signaling pathway. Identifying phytochemicals with the potential to inhibit cancer metastasis by targeting the TGF-β signaling pathway has immense scope for developing a therapeutic strategy against cancer metastasis.

Diagnostic and therapeutic potencies of miR-18a-5p in mixed-type gastric adenocarcinoma

Mixed-type gastric adenocarcinoma (by Lauren Classification) has poor clinical outcomes with few targeted treatment options. The primary objective of this study was to find the prognostic factors, accurate treatment approaches, and effective postoperative adjuvant therapy strategies for patients with mixed-type gastric adenocarcinoma (GA). A microRNA sequencing data set and the corresponding clinical parameters of patients with gastric cancer were obtained from The Cancer Genome Atlas. Differentially expressed microRNAs (DEMs) of diffuse- and intestinal-type GA were, respectively, determined. Kaplan-Meier and log-rank tests were subsequently carried out to evaluate the prognostic relevance of each DEM. To study the common factors between diffuse- and intestinal-type GA, a pathway enrichment analysis was performed on the target genes of identified DEMs using the PANTHER database. After data preprocessing, we analyzed a total of 230 samples from 210 patients with GA. Eighty-six DEMs in diffuse-type GA samples and 59 DEMs in intestinal-type GA samples were, respectively, identified (p  2.0). The Kaplan-Meier survival method further screened out six prognosis-related DEMs for diffuse-type GA and seven prognosis-related DEMs for intestinal-type GA (p < 0.05). MiR-18a-5p was found to be the only common prognosis-related DEM between diffuse- and intestinal-type GA. The common signaling pathways further revealed that target genes of miR-18a-5p are involved in mixed-type GA progression. This study suggests that miR-18a-5p acts as a potential target for treatment, and common signal pathways provide a rich basis to seek reliable and effective molecular targets for the diagnosis, clinical treatment, and postoperative adjuvant therapy strategy of mixed-type GA.

The role of the extracellular matrix protein TGFBI in cancer

The secreted extracellular protein, transforming growth factor beta induced (TGFBI or βIGH3), has roles in regulating numerous biological functions, including cell adhesion and bone formation, both during embryonic development and during the pathogenesis of human disease. TGFBI has been most studied in the context of hereditary corneal dystrophies, where mutations in TGFBI result in accumulation of TGFBI in the cornea. In cancer, early studies focused on TGFBI as a tumor suppressor, in part by promoting chemotherapy sensitivity. However, in established tumors, TGFBI largely has a role in promoting tumor progression, with elevated levels correlating to poorer clinical outcomes. As an important regulator of cancer progression, TGFBI expression and function is tightly regulated by numerous mechanisms including epigenetic silencing through promoter methylation and microRNAs. Mechanisms to target TGFBI have potential clinical utility in treating advanced cancers, while assessing TGFBI levels could be a biomarker for chemotherapy resistance and tumor progression.

Stromal Protein-Mediated Immune Regulation in Digestive Cancers

Simple Summary

Solid cancers are surrounded by a network of non-cancerous cells comprising different cell types, including fibroblasts, and acellular protein structures. This entire network is called the tumor microenvironment (TME) and it provides a physical barrier to the tumor shielding it from infiltrating immune cells, such as lymphocytes, or therapeutic agents. In addition, the TME has been shown to dampen efficient immune responses of infiltrated immune cells, which are key in eliminating cancer cells from the organism. In this review, we will discuss how TME proteins in particular are involved in this dampening effect, known as immunosuppression. We will focus on three different types of digestive cancers: pancreatic cancer, colorectal cancer, and gastric cancer. Moreover, we will discuss current therapeutic approaches using TME proteins as targets to reverse their immunosuppressive effects.

Abstract

The stromal tumor microenvironment (TME) consists of immune cells, vascular and neural structures, cancer-associated fibroblasts (CAFs), as well as extracellular matrix (ECM), and favors immune escape mechanisms promoting the initiation and progression of digestive cancers. Numerous ECM proteins released by stromal and tumor cells are crucial in providing physical rigidity to the TME, though they are also key regulators of the immune response against cancer cells by interacting directly with immune cells or engaging with immune regulatory molecules. Here, we discuss current knowledge of stromal proteins in digestive cancers including pancreatic cancer, colorectal cancer, and gastric cancer, focusing on their functions in inhibiting tumor immunity and enabling drug resistance. Moreover, we will discuss the implication of stromal proteins as therapeutic targets to unleash efficient immunotherapy-based treatments.

TGFβ Signaling in the Tumor Microenvironment

Transforming growth factor beta (TGFβ) is a pleiotropic growth factor. Under normal physiological conditions, TGFβ maintains homeostasis in mammalian tissues by restraining the growth of cells and stimulating apoptosis. However, the role of TGFβ signaling in the carcinogenesis is complex. TGFβ acts as a tumor suppressor in the early stages of disease and as a tumor promoter in its later stages where cancer cells have been relieved from TGFβ growth controls. Overproduction of TGFβ by cancer cells lead to a local fibrotic and immune-suppressive microenvironment that fosters tumor growth and correlates with invasive and metastatic behavior of the cancer cells. Here, we present an overview of the complex biology of the TGFβ family, and we discuss the roles of TGFβ signaling in carcinogenesis and how this knowledge is being leveraged to develop TGFβ inhibition therapies against the tumor.

Hypoxia-Induced TGFBI as a Serum Biomarker for Laboratory Diagnosis and Prognosis in Patients with Pancreatic Ductal Adenocarcinoma

OBJECTIVE

To explore novel biomarkers for patients with pancreatic ductal adenocarcinoma (PDAC), from the perspective of tumor hypoxia.

METHODS

We screened 29 differentially expressed and hypoxia-upregulated genes from the Oncomine database. A total of 12 secretory proteins that interact with hypoxia-inducible factor 1 (HIF-1A) were selected by STRING (protein-protein interaction networks). After excluding enzymes and collagens, insulin-like growth factor-binding protein 3 (IGFBP3), glycoprotein NBM (GPNMB), transforming growth factor-β-induced (TGFBI), and biglycan (BGN) were detected by sandwich enzyme-linked immunosorbent assay (ELISA) in patients with cancer and healthy control individuals.

RESULTS

The serum level of TGFBI was significantly elevated in patients with PDAC, compared with healthy controls; the assay could discriminate among cases of PDAC in different clinical stages. The amount of TGFBI was significantly decreased after treatment. The combination of TGFBI and cancer antigen (CA) 19-9 was more accurate than TGFBI or CA 19-9 alone as diagnostic markers. Also, TGFBI might be used as a prognostic marker according to the PROGgeneV2 Pan Cancer Prognostics Database.

CONCLUSIONS

Serum TGFBI, combined with CA 19-9, offers higher diagnostic value than other methods for patients with PDAC. Also, TGFBI might be used as a prognostic marker.

CD36 Expression Is Associated with Cancer Aggressiveness and Energy Source in Esophageal Squamous Cell Carcinoma

BACKGROUND

Esophageal squamous cell carcinoma (ESCC) is an important cause of cancer-related death worldwide. CD36, a long-chain fatty acid (FA) receptor, can initiate metastasis in human oral squamous cell carcinoma (SCC), and its expression is associated with poor prognosis in several cancers. The clinical significance of CD36 expression and its function in ESCC remain unknown.

METHODS

We examined the clinical significance of CD36 expression in 160 ESCC samples using immunohistochemical staining. Functional analysis was performed to determine the association between CD36 and ESCC characteristics (proliferative ability, invasive ability, and energy source dependency).

RESULTS

Thirty (18.8%) ESCC cases showed high CD36 expression, indicating a significant association with progression. CD36 suppression inhibited proliferation and invasiveness in ESCC cells. ESCC cells with CD36 suppression used specific essential amino acids (EAAs) as energy sources. Cell viability depended on FAs under CD36 expression. The viability of ESCC cells with CD36 suppression depended on EAAs but not FAs.

CONCLUSIONS

CD36 may be a good biomarker and therapeutic target in ESCC. Our data provide new insights into the basic mechanism of CD36-dependent energy utilization for ESCC survival. CD36 might be a key regulator of the dependency of FAs as energy source in ESCC cells.

High RAD18 Expression is Associated with Disease Progression and Poor Prognosis in Patients with Gastric Cancer

BACKGROUND

RAD18 plays an important role in DNA damage repair by inducing monoubiquitinated PCNA (mUB-PCNA) in both cancer and normal tissues. Previous studies have not determined the significance of RAD18 expression in clinical gastric cancer (GC) samples. Thus, this study aimed to clarify the expression and functional significance of RAD18 in GC.

METHODS

Overall, 96 resected GC samples were subjected to an immunohistochemical analysis of RAD18. GC cell lines were also subjected to functional RNA interference analyses of RAD18.

RESULTS

RAD18 expression was predominantly nuclear and was observed at higher levels in GC tissues than in normal tissues. In GC tissues, strong RAD18 expression was associated with progression of lymph node metastasis (p = 0.0001), lymphatic invasion (p = 0.0255), venous invasion (p < 0.0001), recurrence (p = 0.028), and disease stage (p = 0.0253). Moreover, GC patients with high tumor RAD18 expression had shorter overall survival (p = 0.0061) and recurrence-free survival durations (p = 0.035) than those with low tumor RAD18 expression. RAD18 knockdown inhibited GC proliferation and invasiveness and increased chemosensitivity by suppressing mUB-PCNA.

CONCLUSIONS

RAD18 expression may be a useful marker of progression and poor prognosis of GC. Moreover, therapeutic strategies that target RAD18 might be a novel chemosensitizer to eradicate the refractory GC.

Tumor-associated macrophages promote ovarian cancer cell migration by secreting transforming growth factor beta induced (TGFBI) and tenascin C

A central and unique aspect of high-grade serous ovarian carcinoma (HGSC) is the extensive transcoelomic spreading of tumor cell via the peritoneal fluid or malignant ascites. We and others identified tumor-associated macrophages (TAM) in the ascites as promoters of metastasis-associated processes like extracellular matrix (ECM) remodeling, tumor cell migration, adhesion, and invasion. The precise mechanisms and mediators involved in these functions of TAM are, however, largely unknown. We observed that HGSC migration is promoted by soluble mediators from ascites-derived TAM, which can be emulated by conditioned medium from monocyte-derived macrophages (MDM) differentiated in ascites to TAM-like asc-MDM. A similar effect was observed with IL-10-induced alternatively activated m2c-MDM but not with LPS/IFNγ-induced inflammatory m1-MDM. These observations provided the basis for deconvolution of the complex TAM secretome by performing comparative secretome analysis of matched triplets of different MDM phenotypes with different pro-migratory properties (asc-MDM, m2c-MDM, m1-MDM). Mass spectrometric analysis identified an overlapping set of nine proteins secreted by both asc-MDM and m2c-MDM, but not by m1-MDM. Of these, three proteins, i.e., transforming growth factor beta-induced (TGFBI) protein, tenascin C (TNC), and fibronectin (FN1), have been associated with migration-related functions. Intriguingly, increased ascites concentrations of TGFBI, TNC, and fibronectin were associated with short progression-free survival. Furthermore, transcriptome and secretome analyses point to TAM as major producers of these proteins, further supporting an essential role for TAM in promoting HGSC progression. Consistent with this hypothesis, we were able to demonstrate that the migration-inducing potential of asc-MDM and m2c-MDM secretomes is inhibited, at least partially, by neutralizing antibodies against TGFBI and TNC or siRNA-mediated silencing of TGFBI expression. In conclusion, the present study provides the first experimental evidence that TAM-derived TGFBI and TNC in ascites promote HGSC progression.

Role of Cancer-Associated Fibroblast in Gastric Cancer Progression and Resistance to Treatments

Although the survival of gastric cancer (GC) patients has gradually improved, the outcomes of advanced GC patients remain unsatisfactory despite standard treatment with conventional chemotherapy or targeted agents. Several studies have shown that cancer-associated fibroblasts (CAFs), a major component of tumor stroma in GC, may have significant roles in GC progression and resistance to treatments. CAFs are a major source of various secreted molecules in the tumor microenvironment, which stimulate cancer cells and other noncancerous components of GC. Surprisingly, these factors could be involved in gastric carcinogenesis. Cytokines, including interleukin-6 and interleukin-11, or growth factors, such as fibroblast growth factor produced from CAFs, can directly activate GC cells and consequently lead to the development of an aggressive phenotype. Galectin-1 or hepatocyte growth factor can be involved in CAF-derived neovascularization in GC. In addition, recent studies showed that CAFs can affect tumor immunity through M2 polarization of tumor-associated macrophages. Finally, the current study aimed to introduce several inhibitory agents and evaluate their suppressive effects on CAFs in patients with GC progression. However, further studies are required to evaluate their safety and select appropriate patients for application in clinical settings.

Role of the transforming growth factor-β signaling pathway in the pathogenesis of colorectal cancer

The transforming growth factor-β (TGF-β) signaling pathway plays an important role in cancer cell proliferation, growth, metastasis, and apoptosis. It has been shown that TGF-β acts as a tumor suppressor in the early stages of the disease, and as a tumor promoter in its late stages. Mutations in the TGF-β signaling components, the TGF-β receptors and cytoplasmic signaling transducers, are frequently observed in colorectal carcinomas. Exploiting specific TGF-β receptor agonist and antagonist with antitumor properties may be a way of controlling cancer progression. This review summarizes the regulatory role of TGF-β signaling in the pathogenesis of colorectal cancer.