Silencing of ER-resident oxidoreductase PDIA3 inhibits malignant biological behaviors of multidrug-resistant gastric cancer

Single-cell analysis identified PDIA3 as regulator of malignant characteristics and macrophage function in human cancers

Protein disulfide isomerase A3 (PDIA3) is an endoplasmic reticulum (ER) protein. It has different functions including glycoprotein folding in the ER. The unfavorable prognosis of cancer patients was related to the abnormal PDIA3 expression level. However, it is unclear how PDIA3 correlates with the malignant characteristics of different tumors and its impact on tumor immunity. Pan-cancer data were downloaded from several databases for large-scale bioinformatics analysis. The immunological functions of PDIA3 were systematically explored at the single-cell sequencing level, including cell communication, cell metabolism, cell evolution and epigenetic modification. We performed immunofluorescence staining to visualize PDIA3 expression and infiltration of macrophages in pan-cancer samples. Further, we performed a loss-of-function assay of PDIA3 in vitro. The CCK8 assay, clone formation assay, and transwell assay were performed. M2 macrophages were co-cultured with different cell lines before the transwell assay was performed. The immunofluorescence staining of pan-cancer samples presented a higher expression of PDIA3 than those of the paired normal tissues. According to single-cell sequencing analysis, expression of PDIA3 was closely associated with cell communication, cell metabolism, cell evolution and epigenetic modification. The knockdown of PDIA3 in tumor cells inhibited cell proliferation and invasion, and restrained cocultured M2 macrophage migration. Furthermore, PDIA3 displayed predictive value in immunotherapy response in human cancer cohorts, indicating a potential therapeutic target. Our study showed that PDIA3 was associated with tumor malignant characteristics and could mediate the migration of M2 macrophages in various tumor types. PDIA3 could be a promising target to achieve tumor control and improve the immune response on a pan-cancer scale.

An emerging role of N-glycosylation in cancer chemoresistance

Chemoresistance poses a significant obstacle in the effective treatment of cancer, limiting the success of chemotherapy regimens. N-glycosylation, the most important post-translational modification (PTM), plays multifaceted roles in the intricate landscape of cancer progression, particularly drug resistance in cancer cells. This review explores the complex relationship between N-glycosylation and chemoresistance in cancer. Altered glycosylation patterns have been proven to impact drug efflux mechanisms in cancer cells, which can further influence the intracellular concentration of chemotherapy drugs. Moreover, N-glycosylation also plays a regulatory role in cell signaling pathways and apoptosis regulators, continuously affecting the stemness and survival of cancer cells under the selective pressure of chemotherapy. Additionally, the impact of the tumor microenvironment on glycosylation patterns adds complexity to this interplay. This review discusses current research findings, challenges, and future directions based on the roles of N-glycosylation in cancer chemoresistance, emphasizing the potential for targeted therapeutic interventions to enhance the effectiveness of chemotherapy and improve patient outcomes.

Downregulation of PDIA3 inhibits gastric cancer cell growth through cell cycle regulation

OBJECTIVE

Protein disulfide isomerase A3 (PDIA3) promotes the correct folding of newly synthesized glycoproteins in the endoplasmic reticulum. PDIA3 is overexpressed in most tumors, and it may become a biomarker of cancer prognosis and immunotherapy. Our study aims to detect the expression level of PDIA3 in gastric cancer (GC) and its association with GC development as wells as the underlying mechanisms.

METHODS

GC cell lines with PDIA3 knockdown by siRNA, CRISPR-cas9 sgRNAs or a pharmacological inhibitor of LOC14 were prepared and used. PDIA3 knockout GC cells were established by CRISPR-cas9-PDIA3 system. The proliferation, migration, invasion and cell cycle of GC cells were analyzed by cell counting kit-8 assay, wound healing assay, transwell assay and flow cytometry, respectively. Immunodeficient nude mice was used to evaluate the role of PDIA3 in tumor formation. Quantitative PCR and western blot were used for examining gene and protein expressions. RNA sequencing was performed to see the altered gene expression.

RESULTS

The expressions of PDIA3 in GC tissues and cells were increased significantly, and its expression was negatively correlated with the three-year survival rate of GC patients. Down-regulation of PDIA3 by siRNA, LOC14 or CRISPR-cas9 significantly inhibited proliferation, invasion and migration of GC cells TMK1 and AGS, with cell cycle arrested at G2/M phase. Meanwhile, decreased PDIA3 significantly inhibited growth of tumor xenograft in vivo. It was found that cyclin G1 (encoded by CCNG1 gene) expression was decreased by downregulation of PDIA3 in GC cells both in vitro and in vivo. In addition, protein levels of other cell cycle related factors including cyclin D1, CDK2, and CDK6 were also significantly decreased. Further study showed that STAT3 was associated with PDIA3-mediated cyclin G1 regulation.

CONCLUSION

PDIA3 plays an oncogenic role in GC. Our findings unfolded the functional role of PDIA3 in GC development and highlighted a novel target for cancer therapeutic strategy.

The role of PDIA3 in oral squamous cell carcinoma and its value as A diagnostic and prognostic biomarker

Background

This study aimed to investigate the role of protein disulfide isomerase A3 (PDIA3) in oral squamous cell carcinoma (OSCC) and evaluate its significance as a diagnostic and prognostic biomarker.

Methods

Comprehensive bioinformatics analysis of the OSCC dataset from The Cancer Genome Atlas (TCGA) was performed. PDIA3 was depleted in CAL27 and SCC25 OSCC cells by transfection with PDIA3-specific siRNA oligos. The effects of PDIA3 downregulation on cell viability, apoptosis, and cell migration were evaluated using CCK8, ELISA, and wound healing assays, respectively.

Results

The mRNA and protein expression of PDIA3 was significantly up-regulated in OSCC tissues compared to adjacent normal tissues. Knockdown of PDIA3 led to significantly decreased cell viability, increased apoptosis, and suppressed migratory ability in OSCC cells. The Kaplan-Meier survival curve showed that patients with higher PDIA3 expression levels had shorter survival than those with low PDIA3 levels. The receiver operating characteristic (ROC) curve indicated that PDIA3 had high sensitivity and accuracy for detecting OSCC (area under the curve (AUC): 0.917, CI: 0.879-0.955). Univariate and multivariate Cox regression analyses identified PDIA3 as an independent prognostic factor of OSCC. Furthermore, the depletion of PDIA3 inhibited AKT activity in OSCC cells. Gene set enrichment analysis (GSEA) indicated that PDIA3 is involved in various important biological functions and signaling pathways closely related to cancer development.

Conclusion

PDIA3 plays an oncogenic role in OSCC and represents a good candidate as a diagnostic and prognostic biomarker for OSCC.

Protein Disulfide Isomerase A3 (PDIA3): A Pharmacological Target in Glioblastoma?

The protein disulfide isomerase A3 (PDIA3) is directly or indirectly involved in various physiopathological processes and participates in cancer initiation, progression and chemosensitivity. However, little is known about its involvement in glioblastoma. To obtain specific information, we performed cellular experiments in the T98G and U-87 MG glioblastoma cell lines to evaluate the role of PDIA3. The loss of PDIA3 functions, either through inhibition or silencing, reduced glioblastoma cells spreading by triggering cytotoxic phenomena. PDIA3 inhibition led to a redistribution of PDIA3, resulting in the formation of protein aggregates visualized through immunofluorescence staining. Concurrently, cell cycle progression underwent arrest at the G1/S checkpoint. After PDIA3 inhibition, ROS-independent DNA damage and the activation of the repair system occurred, as evidenced by the phosphorylation of H2A.X and the overexpression of the Ku70 protein. We also demonstrated through a clonogenic assay that PDIA3 inhibition could increase the chemosensitivity of T98G and U-87 MG cells to the approved glioblastoma drug temozolomide (TMZ). Overall, PDIA3 inhibition induced cytotoxic effects in the analyzed glioblastoma cell lines. Although further in vivo studies are needed, the results suggested PDIA3 as a novel therapeutic target that could also be included in already approved therapies.

Deciphering STAT3 signaling potential in hepatocellular carcinoma: tumorigenesis, treatment resistance, and pharmacological significance

Hepatocellular carcinoma (HCC) is considered one of the greatest challenges to human life and is the most common form of liver cancer. Treatment of HCC depends on chemotherapy, radiotherapy, surgery, and immunotherapy, all of which have their own drawbacks, and patients may develop resistance to these therapies due to the aggressive behavior of HCC cells. New and effective therapies for HCC can be developed by targeting molecular signaling pathways. The expression of signal transducer and activator of transcription 3 (STAT3) in human cancer cells changes, and during cancer progression, the expression tends to increase. After induction of STAT3 signaling by growth factors and cytokines, STAT3 is phosphorylated and translocated to the nucleus to regulate cancer progression. The concept of the current review revolves around the expression and phosphorylation status of STAT3 in HCC, and studies show that the expression of STAT3 is high during the progression of HCC. This review addresses the function of STAT3 as an oncogenic factor in HCC, as STAT3 is able to prevent apoptosis and thus promote the progression of HCC. Moreover, STAT3 regulates both survival- and death-inducing autophagy in HCC and promotes cancer metastasis by inducing the epithelial-mesenchymal transition (EMT). In addition, upregulation of STAT3 is associated with the occurrence of chemoresistance and radioresistance in HCC. Specifically, non-protein-coding transcripts regulate STAT3 signaling in HCC, and their inhibition by antitumor agents may affect tumor progression. In this review, all these topics are discussed in detail to provide further insight into the role of STAT3 in tumorigenesis, treatment resistance, and pharmacological regulation of HCC.

The Hippo signaling pathway in gastric cancer

Gastric cancer (GC) is an aggressive malignant disease which still lacks effective early diagnosis markers and targeted therapies, representing the fourth-leading cause of cancer-associated death worldwide. The Hippo signaling pathway plays crucial roles in organ size control and tissue homeostasis under physiological conditions, yet its aberrations have been closely associated with several hallmarks of cancer. The last decade witnessed a burst of investigations dissecting how Hippo dysregulation contributes to tumorigenesis, highlighting the therapeutic potential of targeting this pathway for tumor intervention. In this review, we systemically document studies on the Hippo pathway in the contexts of gastric tumor initiation, progression, metastasis, acquired drug resistance, and the emerging development of Hippo-targeting strategies. By summarizing major open questions in this field, we aim to inspire further in-depth understanding of Hippo signaling in GC development, as well as the translational implications of targeting Hippo for GC treatment.

The hsa_circ_0000276-ceRNA regulatory network and immune infiltration in cervical cancer

BACKGROUND

Our previous studies have confirmed that miR-154-5p can regulate pRb expression, and thus, play a tumor suppressor role in HPV16 E7-induced cervical cancer. However, its upstream molecules have not been elucidated in the progression of cervical cancer. This study aimed to explore the role of the miR-154-5p upstream molecule, hsa_circ_0000276 in cervical cancer development and its possible mechanisms of action.

METHODS

We detected differences in whole transcriptome expression profiles of cervical squamous carcinoma and tissues adjacent to cervical cancer tissues from patients using microarray technology to predict circular RNAs (circRNAs) with binding sites to miR-154-5p. Quantitative reverse transcription polymerase chain reaction (qRT-PCR) was used to detect the expression of hsa_circ_0000276 (which had the strongest binding capacity to miR-154 and was selected as the target molecule) in cervical cancer tissues, followed by in vitro functional assays. Downstream microRNAs (miRNAs) and mRNAs of hsa_circ_0000276 were identified using transcriptome microarray data and databases, while the protein-protein interaction networks were obtained using STRING. A competing endogenous RNA (ceRNA) network centered on hsa_circ_0000276 was constructed using Cytoscape and GO and KEGG databases. Abnormal expression and prognosis of critical downstream molecules were analyzed using gene databases and molecular experiments. qRT-PCR and western blot analysis was performed to verify the expression of candidate genes.

RESULTS

We identified 4,001 differentially expressed circRNAs between HPV16-positive cervical squamous carcinoma and benign cervical tissues and 760 circRNAs targeting miR-154-5p, including hsa_circ_0000276. hsa_circ_0000276 and miR-154-5p directly bound, and hsa_circ_0000276 was upregulated, in cervical precancerous lesions and cervical cancer tissues and cells. Silencing hsa_circ_0000276 inhibited G1/S transition and cell proliferation and promoted apoptosis in SiHa and CaSki cells. Bioinformatics analysis showed that the hsa_circ_0000276 ceRNA network included 17 miRNAs and seven mRNAs, and downstream molecules of hsa_circ_0000276 were upregulated in cervical cancer tissues. These downstream molecules were associated with a poor prognosis and affected cervical cancer-associated immune infiltration. Of these, expression of CD47, LDHA, PDIA3, and SLC16A1 was downregulated in sh_hsa_circ_0000276 cells.

CONCLUSIONS

Our findings show that hsa_circ_0000276 exerts cancer-promoting effects in cervical cancer and is an underlying biomarker for cervical squamous cell carcinoma.

Preclinical evaluation of oncolytic potential human rotavirus Wt 1-5 in gastric adenocarcinoma

Despite advances in biomedical research, gastric cancer remains the leading cause of morbidity and mortality worldwide due to the limited efficacy of conventional therapies. In recent decades, oncolytic viruses have emerged as a biological therapeutic alternative to cancer due to their selectivity, effectiveness, and low toxicity. However, clinical trials have shown that developing a virus with selectivity for multiple tumor receptors and the ability to penetrate and diffuse through the tumor microenvironment to reactivate the immune system remains challenging. This study aimed to examine the oncolytic potential of tumor cell-adapted rotavirus Wt1-5 in gastric adenocarcinoma samples. This study focused on determining the propagation capacity of the RV Wt1-5 through the tumor and the importance of the expression of cell surface co-receptors, including integrin β3, protein disulfide isomerase (PDI), and heat shock proteins (Hsp-90, -70, -60, -40, and Hsc 70), during infection of tumor cells. These proteins were found to be differentially expressed in tumor cells compared to adjacent non-tumor cells. Preincubation of gastric tumor cells with antibodies against these proteins decreased rotavirus infections, validating their importance in the binding and entry of RV Wt1-5 into tumor cells, as previously reported. Upon RV infection, apoptosis was one of the types of death that was observed. This was evidenced by evaluating the expression of CASP-3, -9, PARP, cytochrome C, Bax, Bid, p53, and Bcl-2, as well as observing morphological changes such as chromatin margination, nuclear condensation, and fragmentation. Finally, at 60 h.p.i, histological analysis revealed that oncolysis compromised the entire thickness of the tumor. Therefore, the results suggest that RV Wt1-5 could be a novel therapeutic agent co-adjuvant agent for conventional and targeted therapies in managing GC. Ex vivo infection of the tumor tissue model showed characteristics of an immune response that could be explored in future studies.