High expression levels of polymeric immunoglobulin receptor are correlated with chemoresistance and poor prognosis in pancreatic cancer

Development and Validation of the Predictive and Prognostic ChemoResist Signature in Resected Pancreatic Ductal Adenocarcinoma: Multicohort Study

OBJECTIVE

To develop and validate a signature to precisely predict prognosis in pancreatic ductal adenocarcinoma (PDAC) undergoing resection and adjuvant chemotherapy.

BACKGROUND

PDAC is largely heterogeneous and responds discrepantly to treatment.

METHODS

A total of 551 consecutive patients with PDAC from 3 different cohorts of tertiary centers were initially enrolled. Genetic events of the 4 most commonly mutated genes in PDAC and expressions of 12 PI3K/AKT/mammalian target of rapamycin (mTOR) pathway markers were examined. A 9-feature signature for the prediction of chemotherapy benefits was constructed in the training cohort using the least absolute shrinkage and selection operator Cox regression model and validated in 2 independent cohorts.

RESULTS

Utilizing the least absolute shrinkage and selection operator model, a predictive and prognostic signature, named ChemoResist, was established based on KRAS single nucleotide variant (SNV), phosphatase and tensin homologue (PTEN), and mTOR expressions, and 6 clinicopathologic features. Significant differences in survival were observed between high and low-ChemoResist patients receiving chemotherapy in both the training [median overall survival (OS), 17 vs 42 months, P < 0.001; median disease-free survival (DFS), 10 vs 23 months, P < 0.001] and validation cohorts (median OS, 18 vs 35 months, P = 0.034; median DFS, 11 vs 20 months, P = 0.028). The ChemoResist classifier also significantly differentiated patient survival in whole patients regardless of chemotherapy. Multivariable-adjusted analysis substantiated the ChemoResist signature as an independent predictive and prognostic factor. For predicting 2-year OS, the ChemoResist classifier had significantly higher areas under the curve than TNM stage (0.788 vs 0.636, P < 0.001), other clinicopathologic characteristics (0.505-0.668), and single molecular markers (0.507-0.591) in the training cohort. Furthermore, patients with low ChemoResist scores exhibited a more favorable response to adjuvant chemotherapy compared with those with high ChemoResist scores (hazard ratio for OS: training, 0.22 vs 0.57; validation, 0.26 vs 0.50; hazard ratio for DFS: training, 0.35 vs 0.54; validation, 0.18 vs 0.59). The ChemoResist signature was further validated in the total cohort undergoing R0 resection.

CONCLUSIONS

The ChemoResist signature could precisely predict survival in PDAC undergoing resection and chemotherapy, and its predictive value surpassed the TNM stage and other clinicopathologic factors. Moreover, the ChemoResist classifier could assist with identifying patients who would more likely benefit from adjuvant chemotherapy.

Examining the Use of Serum Biomarkers to Guide Early Detection of Pancreatic Cancer

BACKGROUND

Pancreatic cancer is estimated to become the second leading cause of cancer-related death by 2030 because of high malignancy, late diagnosis, inefficient therapy, and a lack of available screening for early detection.

OBJECTIVES

This article presents current clinical data supporting the use of serum biomarker signatures as a modality for early pancreatic ductal adenocarcinoma (PDAC) diagnosis and treatment.

METHODS

A clinical case study highlights the use of serum biomarker signatures in PDAC diagnosis. Clinical guidelines on PDAC were obtained from the National Comprehensive Cancer Network, the National Cancer Institute, StatPearls Publishing, the American Cancer Society, and the Pancreatic Cancer Detection Consortium.

FINDINGS

Screening barriers involve a low incidence and histologic heterogeneity of disease, as well as a need for prospective multicenter analysis of proposed biomarkers. Because the poor prognosis of PDAC is attributed to late detection, the development of a clinical guideline for biomarker-based screening warrants interprofessional awareness and advocacy in oncology clinical practice.

LINC00870 promotes imatinib resistance in gastrointestinal stromal tumor via inhibiting PIGR glycosylation modifications

Imatinib is the first-line targeted therapy for gastrointestinal stromal tumor (GIST), but resistance frequently occurs during treatment, limiting its efficacy and clinical application. We performed high-throughput sequencing of tissue specimens from imatinib-resistant GIST patients, and identified significantly high expression of polymeric immunoglobulin receptor (PIGR) in imatinib-resistant cell lines. Further investigation revealed that PIGR binds specifically to LINC00870. The findings from in vitro cell functional experiments provide evidence of a strong association between LINC00870 and PIGR and the processes of proliferation and metastasis in GIST. Overexpression of LINC00870 in GIST significantly inhibits the glycosylation modification and secretion of the extracellular region of PIGR, leading to immune dysregulation. The inhibition of PIGR or LINC00870 effectively surmounts imatinib resistance. Our study identified PIGR as a critical molecule in regulating GIST imatinib resistance and elucidated the mechanism by which PIGR promotes imatinib resistance through LINC00870 inhibition of PIGR glycosylation modifications. These findings provide a new theoretical basis for blocking drug resistance and improving prognosis in GIST.

Enhancing liver fibrosis detection: a novel PIGR-utilizing approach in chronic hepatitis B injury assessment

BACKGROUND

Chronic Hepatitis B (CHB) is a leading cause of liver fibrosis and cirrhosis worldwide. The early detection of liver fibrosis remains challenging due to the lack of specific symptoms and noninvasive biomarkers with high sensitivity. The polymeric immunoglobulin receptor (PIGR) has recently emerged as a potential biomarker for liver fibrosis. This study aims to evaluate the utility of PIGR in CHB patients as a biomarker for liver fibrosis.

METHODS

This retrospective study analyzed 150 CHB patients from 2018 to 2023. Based on liver biopsy results, 34 patients were classified as having liver fibrosis, while 116 were categorized as non-fibrosis. Clinical data were compared to assess the relationship between PIGR expression levels and serum fibrosis indices. Logistic regression was performed to identify factors influencing liver fibrosis, and the predictive value of PIGR was evaluated using a receiver operating characteristic (ROC) curve.

RESULTS

Significant differences were observed in collagen type IV (CIV), procollagen type III N-terminal peptide (PCIIINP), and hyaluronic acid (HA) levels between the fibrosis and non-fibrosis groups (P < 0.05). PIGR levels were significantly higher in the fibrosis group (P < 0.05) and positively correlated with HA, laminin (LN), PCIII, and CIV levels (P < 0.05). Logistic regression identified HA, LN, PCIIINP, and CIV as risk factors, with PIGR being an independent predictor (P < 0.05). At a cutoff value of 0.35, PIGR showed an area under the curve (AUC) of 0.839, with 81.90% sensitivity, 79.41% specificity, and a Youden's index of 0.613. PIGR also provided a higher net benefit than APRI.

CONCLUSION

PIGR levels are significantly elevated in CHB-related liver fibrosis and correlate closely with established fibrosis markers. As an independent predictor, PIGR demonstrates high diagnostic accuracy and holds promise as a non-invasive biomarker for detecting liver fibrosis in CHB patients, with significant potential for clinical application.

Molecular biomarkers involved in the progression of gallbladder inflammatory lesions to invasive cancer: A proteomic approach

The progression of gallbladder inflammatory lesions to invasive cancer remains poorly understood, necessitating research on biomarkers involved in this transition. This study aims to identify and validate proteins associated with this progression, offering insights into potential diagnostic biomarkers for gallbladder cancer (GBC). Label-free liquid chromatography-assisted tandem mass spectrometry (LC-MS/MS) proteomics was performed on samples from ten cases each of GBC and inflammatory lesions, with technical duplicates. Validation was conducted through the enzyme-linked immunosorbent assay (ELISA) using 80 samples (40 GBC and 40 inflammatory lesions). Bioinformatics tools analyzed protein-protein interaction (PPI) networks and pathways. Statistical correlations with clinicopathological variables were assessed. Prognostic evaluation utilized Kaplan-Meier survival analysis and Cox regression analyses. mRNA expressions were studied using real-time-polymerase chain reaction (RT-PCR). Out of 5714 proteins analyzed, 621 were differentially expressed. Three upregulated (the S100 calcium-binding protein P [S100P], polymeric immunoglobulin receptor [PIGR], and complement C1q-binding protein [C1QBP]) and two downregulated (transgelin [TAGLN] and calponin 1 [CNN1]) proteins showed significant expression. Pathway analysis implicated involvement of proteoglycans in cancer and glycosaminoglycan metabolism. Significant correlations were observed between protein concentrations and clinicopathological variables. Prognostic factors, such as tumor size, lymph node metastasis, and preoperative bilirubin levels were associated with overall survival (OS). Protein-based assays demonstrated higher resolution compared to mRNA analysis, suggesting their utility in GBC risk stratification. S100P, PIGR, C1QBP, TAGLN, and CNN1 emerge as potential protein-based biomarkers involved in the progression from gallbladder inflammatory lesions to invasive cancer. These findings hold promise for improved diagnostic and prognostic strategies in GBC management.

Comparative proteomics analysis of the mouse mini-gut organoid: insights into markers of gluten challenge from celiac disease intestinal biopsies

Introduction

Organoid models enable three-dimensional representation of cellular systems, providing flexible and accessible research tools, and can highlight key biomolecules. Such models of the intestinal epithelium can provide significant knowledge for the study of celiac disease and provide an additional context for the nature of markers observed from patient biopsy data.

Methods

Using LC-MS/MS, the proteomes of the crypt and enterocyte-like states of a mouse mini-gut organoid model were measured. The data were further compared with published biopsy data by comparing the changes induced by gluten challenge after a gluten-free diet.

Results and discussion

These analyses identified 4,850 protein groups and revealed how 400 putative biomarkers of dietary challenge were differentially expressed in the organoid model. In addition to the extensive changes within the differentiated cells, the data reiterated the disruption of the crypt-villus axis after gluten challenge. The mass spectrometry data are available via ProteomeXchange with the identifier PXD025690.

Polymeric immunoglobulin receptor (pIgR) in cancer

BACKGROUND

The polymeric immunoglobulin receptor (pIgR) is a transmembrane transporter of polymeric IgA through the intestinal epithelium. Its overexpression has been reported in several cancers, but its role as a diagnostic and prognostic biomarker of oncogenesis is currently unclear.

METHOD

A literature search was conducted to summarize the functions of pIgR, its expression levels, and its clinical implications.

RESULTS

pIgR expression has previously been investigated by proteomic analysis, RNA sequencing, and tissue microarray at the level of both RNA and protein in various cancers including pancreatic, esophageal, gastric, lung, and liver. However, studies have reported inconsistent results on how pIgR levels affect clinical outcomes such as survival rate and chemotherapy resistance. Possible explanations include pIgR mRNA levels being minimally correlated with the rate of downstream pIgR protein synthesis, and the diversity of antibodies used in immunohistochemistry studies further magnifying this ambiguity. In ovarian cancer cells, the transcytosis of IgA accompanied a series of transcriptional changes in intracellular inflammatory pathways that inhibit the progression of cancer, including the upregulation of IFN-gamma and downregulation of tumor-promoting ephrins. These findings suggest that both the levels of pIgR and secreted IgA from tumor-infiltrating B cells affect clinical outcomes.

CONCLUSION

Overall, no direct correlation was observed between the levels of pIgR inside tumor tissue and the clinical features in cancer patients. Measuring pIgR protein levels with a more specific and possibly chemically defined antibody, along with tumoral IgA, is a potential solution to better understand the pathways and consequences of pIgR overexpression in cancer cells.

Expression of polymeric immunoglobulin receptor (PIGR) and the effect of PIGR overexpression on breast cancer cells

Polymeric immunoglobulin receptor (PIGR) has a major role in mucosal immunity as a transporter of polymeric immunoglobulin across the epithelial cells. The aim of this study was to determine the effect of PIGR on cellular behaviours and chemo-sensitivity of MCF7 and MDA-MB468 breast cancer cell lines. Basal levels of PIGR mRNA and protein expression in MCF7 and MDA-MB468 cells were evaluated by real time quantitative polymerase chain reaction and Western blotting, respectively. MCF7/PIGR and MDA-MB468/PIGR stable cell lines, overexpressing the PIGR gene, were generated using a lentiviral vector with tetracycline dependent induction of expression. Cell viability, cell proliferation and chemo-sensitivity of PIGR transfected cells were evaluated and compared with un-transfected cells to determine the effect of PIGR overexpression on cell phenotype. The levels of PIGR mRNA and protein expression were significantly higher in MDA-MB468 cells than in MCF7 cells (380-fold, p < 0.0001). However, the differential expression of PIGR in these two cell lines did not lead to significant differences in chemosensitivity. Viral overexpression of PIGR was also not found to change any of the parameters measured in either cell line. PIGR per se did not affect cellular behaviours and chemosensitivity of these breast cancer cell lines.

Differential plasma proteomes of the patients with Opisthorchiasis viverrini and cholangiocarcinoma identify a polymeric immunoglobulin receptor as a potential biomarker

In Southeast Asian countries, nitrosamine compounds and the liver fluke Opisthorchis viverrini have long been identified as carcinogens for cholangiocarcinoma (CHCA). In order to effectively treat O. viverrini infections and prevent the development of CHCA, methods for disease detection are needed. This study aims to identify biomarkers for O. viverrini infection and CHCA. In the discovery phase, technical triplicates of five pooled plasma pools (10 plasma each) of healthy control subjects (noOVCCA), O. viverrini subjects (OV), and cholangiocarcinoma subjects (CCA), underwent solution-based digestion, with the label-free method, using a Thermo Scientific™ Q Exactive™ HF hybrid quadrupole-Orbitrap mass spectrometer and UltiMate 300 LC systems. The noOVCCA, OV, and CCA groups demonstrated different profiles and were clustered, as illustrated by PCA and heat map analysis. The STRING and reactome analysis showed that both OV and CCA groups up-regulated proteins targeting immune system-related proteins. Differential proteomic profiles, S100A9, and polymeric immunoglobulin receptor (PIGR) were specifically expressed in the CCA group. During the validation phase, another 50 plasma samples were validated via the PIGR sandwich ELISA. Using PIGR >1.559 ng/ml as a cut-off point, 78.00% sensitivity, 71.00% specificity, and AUC = 0.8216, were obtained. It is sufficient to differentially diagnose cholangiocarcinoma patients from healthy patients and those with Opisthorchiasis viverrini. Hence, in this study, PIGR was identified and validated as a potential biomarker for CHCA. Plasma PIGR is suggested for screening CHCA, especially in an endemic region of O. viverrini infection.

The Underlying Roles of Exosome-Associated PIGR in Fatty Acid Metabolism and Immune Signaling in Colorectal Cancer

The polymeric immunoglobulin receptor (PIGR), an exosome-associated glycoprotein, plays an important role in the occurrence and development of different tumors. This study aimed to investigate whether PIGR is essential for colorectal cancer (CRC). Comprehensive bioinformatics analysis and immunohistochemistry (IHC) revealed that expression of PIGR was significantly decreased in CRC patients. Upregulated PIGR displayed favorable prognostic values in CRC patients. Several algorithms, such as TISIDB and TIMER, were used to evaluate the roles of PIGR expression in the regulation of immune response in CRC. Moreover, GSEA enrichment analysis indicated the underlying role of PIGR in the regulation of fatty acid metabolism in CRC. Taken together, our findings might provide a new potential prognostic and immune-associated biomarker for CRC and supply a new destination for PIGR-related immunotherapy in clinical treatment.

Patient pIgR-enriched extracellular vesicles drive cancer stemness, tumorigenesis and metastasis in hepatocellular carcinoma

BACKGROUND & AIMS

Extracellular vesicles (EVs) play a pivotal role in connecting tumor cells with their local and distant microenvironments. Herein, we aimed to understand the role (on a molecular basis) patient-derived EVs play in modulating cancer stemness and tumorigenesis in the context of hepatocellular carcinoma (HCC).

METHODS

EVs from patient sera were isolated, quantified and characterized. The EVs were vigorously tested, both in vitro and in vivo, through various functional assays. Proteomic analysis was performed to identify the functional components of EVs. The presence and level of polymeric immunoglobulin receptor (pIgR) in circulating EVs and tumor and non-tumorous tissues of patients with HCC were determined by ELISA, immunoblotting, immunohistochemistry and quantitative PCR. The functional role and underlying mechanism of EVs with enhanced pIgR expression were elucidated. Blockade of EV-pIgR with neutralizing antibody was performed in nude mice implanted with patient-derived tumor xenografts (PDTXs).

RESULTS

Circulating EVs from patients with late-stage HCC (L-HCC) had significantly elevated pIgR expression compared to the EVs released by control individuals. The augmenting effect of L-HCC-EVs on cancer stemness and tumorigenesis was hindered by an anti-pIgR antibody. EVs enriched with pIgR consistently promoted cancer stemness and cancerous phenotypes in recipient cells. Mechanistically, EV-pIgR-induced cancer aggressiveness was abrogated by Akt and β-catenin inhibitors, confirming that the role of EV-pIgR depends on the activation of the PDK1/Akt/GSK3β/β-catenin signaling axis. Furthermore, an anti-pIgR neutralizing antibody attenuated tumor growth in mice implanted with PDTXs.

CONCLUSIONS

This study illustrates a previously unknown role of EV-pIgR in regulating cancer stemness and aggressiveness: EV-pIgR activates PDK1/Akt/GSK3β/β-catenin signaling cascades. The blockade of the intercellular communication mediated by EV-pIgR in the tumor microenvironment may provide a new therapeutic strategy for patients with cancer.

LAY SUMMARY

The World Health Organization estimates that more than 1 million patients will die from liver cancer, mostly hepatocellular carcinoma (HCC), in 2030. Understanding the underlying mechanism by which HCC acquires aggressive attributes is crucial to improving the diagnosis and treatment of patients. Herein, we demonstrated that nanometer-sized extracellular vesicles released by tumors promote cancer stemness and tumorigenesis. Within these oncogenic vesicles, we identified a key component that functions as a potent modulator of cancer aggressiveness. By inhibiting this functional component of EVs using a neutralizing antibody, tumor growth was profoundly attenuated in mice. This hints at a potentially effective therapeutic alternative for patients with cancer.

Tumor mutation burden (TMB)-associated signature constructed to predict survival of lung squamous cell carcinoma patients

Lung squamous cell carcinoma (LUSC) is a common type of lung cancer with high incidence and mortality rate. Tumor mutational burden (TMB) is an emerging biomarker for selecting patients with non-small cell lung cancer (NSCLC) for immunotherapy. This study aimed to reveal TMB involved in the mechanisms of LUSC and develop a model to predict the overall survival of LUSC patients. The information of patients with LUSC were obtained from the cancer genome atlas database (TCGA). Differentially expressed genes (DEGs) between low- and the high-TMB groups were identified and taken as nodes for the protein-protein interaction (PPI) network construction. Gene oncology (GO) enrichment analysis and gene set enrichment analysis (GSEA) were used to investigate the potential molecular mechanism. Then, we identified the factors affecting the prognosis of LUSC through cox analysis, and developed a risk score signature. Kaplan-Meier method was conducted to analyze the difference in survival between the high- and low-risk groups. We constructed a nomogram based on the risk score model and clinical characteristics to predict the overall survival of patients with LUSC. Finally, the signature and nomogram were further validated by using the gene expression data downloaded from the Gene Expression Omnibus (GEO) database. 30 DEGs between high- and low-TMB groups were identified. PPI analysis identified CD22, TLR10, PIGR and SELE as the hub genes. Cox analysis indicated that FAM107A, IGLL1, SELE and T stage were independent prognostic factors of LUSC. Low-risk scores group lived longer than that of patients with high-risk scores in LUSC. Finally, we built a nomogram that integrated the clinical characteristics (TMN stage, age, gender) with the three-gene signature to predict the survival probability of LUSC patients. Further verification in the GEO dataset. TMB might contribute to the pathogenesis of LUSC. TMB-associated genes can be used to develope a model to predict the OS of lung squamous cell carcinoma patients.

Role of Polymeric Immunoglobulin Receptor in IgA and IgM Transcytosis

Transcytosis of polymeric IgA and IgM from the basolateral surface to the apical side of the epithelium and subsequent secretion into mucosal fluids are mediated by the polymeric immunoglobulin receptor (pIgR). Secreted IgA and IgM have vital roles in mucosal immunity in response to pathogenic infections. Binding and recognition of polymeric IgA and IgM by pIgR require the joining chain (J chain), a small protein essential in the formation and stabilization of polymeric Ig structures. Recent studies have identified marginal zone B and B1 cell-specific protein (MZB1) as a novel regulator of polymeric IgA and IgM formation. MZB1 might facilitate IgA and IgM transcytosis by promoting the binding of J chain to Ig. In this review, we discuss the roles of pIgR in transcytosis of IgA and IgM, the roles of J chain in the formation of polymeric IgA and IgM and recognition by pIgR, and focus particularly on recent progress in understanding the roles of MZB1, a molecular chaperone protein.