The pancreatic ductal adenocarcinoma (PDAC) microenvironment contains dense desmoplastic stroma dominated by cancer-associated fibroblasts (CAFs) and is crucial to cancer development and progression. Several studies have revealed that thrombospondin 2 (THBS2) is a valuable serological-marker in PDAC. However, the detailed mechanism of the cancer-stroma interactome remains unclear. Here we showed that elevated THBS2 expression in PDAC was predominantly restricted to stroma and correlated with tumor progression and poor prognosis by quantitative proteomics and immunohistochemistry analyses. RNA in situ hybridization confirmed that CAFs but not neoplastic cells expressed THBS2 in precancerous lesions and its levels gradually increased with disease progression in genetically engineered mouse models. Mechanistically, cancer cell-secreted TGF-β1 activated CAFs to induce THBS2 expression via the p-Smad2/3 pathway. Consequently, CAF-derived THBS2 bound to the membrane receptors integrin α_vβ₃/CD36 and activated the MAPK pathway in PDAC cells to promote tumor growth and adhesion in vitro and in vivo. Inhibition of integrin α_vβ₃, CD36, MEK and JNK rescued THBS2-induced malignant phenotypes. In conclusion, the TGF-β1-THBS2-integrin α_vβ₃/CD36-MAPK cascade forms a complex feedback circuit to mediate reciprocal interactions of pancreatic cancer cells-CAFs. THBS2 may act as a novel therapeutic-target to block the cancer-stroma communication.

Pancreatic ductal adenocarcinoma (PDAC) is the most lethal cancer in humans, with a 5‐year survival rate of <5%. Recently, glypican‐1 (GPC1)‐expressing circulating exosomes were found to be a promising diagnostic tool for PDAC. However, the aberrant expression of GPC1 has not been systematically evaluated in large‐scale clinical samples of PDAC. Here, we performed a comprehensive analysis of GPC1 mRNA and protein expression features. Included in this study were 178 PDAC patients from the cancer genome atlas (TCGA) and 186 subjects whose tissues were used in immunohistochemical staining assays. We demonstrated that GPC1 mRNA was silenced in normal pancreata; however, it was re‐expressed in PDAC tissues probably because of the promoter hypomethylation. The GPC1 protein was barely expressed in the normal and adjacent noncancerous pancreata. In tumor tissues, 59.7% (111/186) of the detected samples showed positive expression. Notably, GPC1 was elevated in 63.6% (34/55) of early stage cases. High levels of GPC1 were associated with poorer differentiation and larger tumor diameters. Kaplan–Meier analysis showed a significant difference in overall survival between the groups categorized by GPC1 expression (P = 0.0028). Multivariate analyses indicated that GPC1 was a significant risk factor for poor overall survival with a 1.82‐fold increase in the hazard ratio (P = 0.0022). In conclusion, during pancreatic tumorigenesis, GPC1 was ectopically expressed and served as an independent poor prognostic factor. Our findings highlighted the alluring prospect of GPC1 as an early diagnostic and prognostic marker as well as a therapeutic target for PDAC.

Currently, imaging, fecal immunochemical tests (FITs) and serum carcinoembryonic antigen (CEA) tests are not adequate for the early detection and evaluation of metastasis and recurrence in colorectal cancer (CRC). To comprehensively identify and validate more accurate noninvasive biomarkers in urine, we implement a staged discovery-verification-validation pipeline in 657 urine and 993 tissue samples from healthy controls and CRC patients with a distinct metastatic risk. The generated diagnostic signature combined with the FIT test reveals a significantly increased sensitivity (+21.2% in the training set, +43.7% in the validation set) compared to FIT alone. Moreover, the generated metastatic signature for risk stratification correctly predicts over 50% of CEA-negative metastatic patients. The tissue validation shows that elevated urinary protein biomarkers reflect their alterations in tissue. Here, we show promising urinary protein signatures and provide potential interventional targets to reliably detect CRC, although further multi-center external validation is needed to generalize the findings.

Esophageal squamous cell carcinoma (ESCC) is one of the fatal malignancies worldwide. It has an increased propensity to metastasize via lymphogenous routes in an early stage. The prognosis of patients with lymph node metastases (LNM) is often worse than that of patients without metastases. Although several factors have been found to influence metastasis, the mechanisms of preference for specific metastatic routes remain poorly understood. Herein, we provide evidence that the intrinsic hypersensitivity of tumor cells to ferroptosis may proactively drive lymphatic metastasis. Serum autoantibodies associated with LNM of early ESCC were screened using a whole-proteome protein array containing 19 394 human recombinant proteins, and an anti-BACH1 autoantibody was first identified. Pan-cancer analysis of ferroptosis-related genes with preferential lymphatic metastasis and preferential hematogenous metastasis based on The Cancer Genome Atlas data was performed. Only BACH1 showed significant overexpression in tumors with preferential lymphatic metastasis, whereas it was downregulated in most tumors with preferential nonlymphatic metastasis. In addition, it was found that the serum levels of autoantibodies against BACH1 were elevated in early-stage patients with LNM. Interestingly, BACH1 overexpression and ferroptosis induction promoted LNM but inhibited hematogenous metastasis in mouse models. Transcriptomic and lipidomic analyses found that BACH1 repressed SCD1-mediated biosynthesis of monounsaturated fatty acids, especially oleic acid (OA). OA significantly attenuated the ferroptotic phenotypes and reversed the metastatic properties of BACH1-overexpressing cells. OA addition significantly rescued the ferroptotic phenotypes and reversed the metastatic properties of BACH1-overexpressing cells. Importantly, the concentration gradient of OA between primary lesions and the lymph resulted in the chemoattraction of tumor cells to promote invasion, thus facilitating lymphatic metastasis. BACH1-induced ferroptosis drives lymphatic metastasis via the BACH1-SCD1-OA axis. More importantly, this study confirms that ferroptosis is a double-edged sword in tumorigenesis and tumor progression. The clinical application of ferroptosis-associated agents requires a great caution.

Objective Tumor metastasis is a complex, multistep process that depends on tumor cells and their communication with the tumor microenvironment. A p53 gain-of-function mutant has been shown to enhance the tumorigenesis, invasion, and metastasis abilities of tumor cells. This study aimed to investigate the roles of p53 R273H mutation in the tumor microenvironment. Methods The in vitro and in vivo effects of the p53 R273H mutant on the invasion and metastasis of HCT116 cells were investigated. Exosomes from wild-type and HCT116-TP53(R273H) cells were cocultured with mouse embryonic fibroblasts (MEFs). The roles of differentially expressed exosomal microRNAs identified by microarray analysis were investigated. The functions of the p53 R273H mutant in tumor cells were also investigated via gene expression microarray and quantitative polymerase chain reaction (qPCR) analyses. Results Introducing p53 R273H mutant into HCT116 cells significantly potentiated pulmonary metastasis in vivo. In the presence of exosomes derived from HCT116-TP53(R273H) cells, the exosomes were taken up by MEFs and became activated. Microarray analysis showed that the p53 R273H mutation increased the exosomal levels of miR-21-3p and miR-769-3p. Intriguingly, in clinical samples, miR-21-3p and miR-769-3p levels were significantly higher in patients with a p53 mutation than in those without this mutation. Furthermore, both miR-21-3p and miR-769-3p activated fibroblasts and exerted a synergistic effect via their target genes on the transforming growth factor-β (TGF-β)/Smad signaling pathway. The activated fibroblasts excreted cytokine TGF-β and may have reciprocally induced cancer cells to undergo epithelial-mesenchymal transition (EMT). Indeed, HCT116-TP53(R273H) cells showed increased expression of ZEB1 and SNAI2 and decreased transcription of several cell adhesion molecules. Conclusions The mutant p53-exosomal miR-21-3p/miR-769-3p-fibroblast-cytokine circuit appears to be responsible for communication between tumor and stromal cells, with exosomal miRNAs acting as a bridge. miR-21-3p and miR-769-3p are potential predictive markers of pulmonary metastasis and candidate targets for therapeutic interventions.

Metastasis to regional lymph nodes or distal organs predicts the progression of the disease and poor prognosis in esophageal squamous cell carcinoma (ESCC). Previous studies demonstrated that BTB and CNC homology 1 (BACH1) participates in various types of tumor metastasis. However, the function of BACH1 in ESCC was rarely reported. The present study demonstrated that BACH1 protein was overexpressed in ESCC tissues compared with paired esophageal epithelial tissues according to immunohistochemical staining (IHC). Higher levels of BACH1 mRNA were associated with decreased overall survival (OS) and shorter disease‐free survival (DFS) of ESCC patients based on an analysis of The Cancer Genome Atlas (TCGA) datasets. BACH1 significantly enhanced the migration and invasion of ESCC in vitro. Mechanistically, BACH1 promoted the epithelial–mesenchymal transition (EMT) by directly activating the transcription of CDH2, SNAI2, and VIM, as determined by chromatin immunoprecipitation‐quantitative polymerase chain reaction (ChIP‐qPCR). BACH1 overexpression significantly enhanced CDH2 promoter activity according to the results of a luciferase assay. The results of subsequent experiments indicated that BACH1 enhanced the growth of tumor xenografts. The density of CD31⁺ blood vessels and the expression of vascular endothelial growth factor C (VEGFC) in tumor xenografts were significantly associated with BACH1 levels according to the results of IHC and immunofluorescence (IF) analyses performed in vivo. Moreover, ChIP‐qPCR analysis demonstrated that the transcriptional activity of VEGFC was also upregulated by BACH1. Thus, BACH1 contributes to ESCC metastasis and tumorigenesis by partially facilitating the EMT and angiogenesis, and BACH1 may be a promising therapeutic target or molecular marker in ESCC.