Guoxiong Xu

FLOT1 Is a Novel Serum Biomarker of Ovarian Cancer Targeted by N6‐methyladenosine Modification Inhibition

ABSTRACTOvarian cancer (OC) is a deadly disease and lacks a precise marker for diagnosis worldwide. Our previous work has shown the overexpression of flotillin‐1 (FLOT1) in OC tissue. To improve diagnostic sensitivity and accuracy, we evaluated the serum level of FLOT1 in OC patients and found that the serum concentration of FLOT1 as well as CA125 was significantly increased in patients with OC compared with healthy control (p < 0.01) and those with benign tumors (p < 0.05). The detection rate (above the upper limit of a cut‐off value) of FLOT1 and CA125 was 77.78% and 72.22%, respectively, in patients with OC, which was increased to 88.89% in combination. The elevation of FLOT1 was confirmed in the serum of nude mice after the implantation of human OC cells. A high level of FLOT1 protein in the serum was positively correlated with the overexpression of FLOT1 protein in OC tissues. Furthermore, the level of m6A modification of FLOT1 mRNA was significantly high in OC cells compared with normal ovarian epithelial cells, leading to an increase in FLOT1 mRNA expression. Application of a methylation inhibitor, 3‐deazaadenosine, decreased FLOT1 mRNA expression in OC cells and suppressed tumor formation in a xenograft mouse model. In conclusion, the current study demonstrated that FLOT1 is a novel serum biomarker of OC and can be targeted by m6A modification inhibition. These data highlight the potential application of FLOT1 as a diagnostic marker and a therapeutic target for patients with OC.

Prediction Model for Therapeutic Responses in Ovarian Cancer Patients using Paclitaxel-resistant Immune-related lncRNAs

Background: Ovarian cancer (OC) is the deadliest malignant tumor in women with a poor prognosis due to drug resistance and lack of prediction tools for therapeutic responses to anti- cancer drugs. Objective: The objective of this study was to launch a prediction model for therapeutic responses in OC patients. Methods: The RNA-seq technique was used to identify differentially expressed paclitaxel (PTX)- resistant lncRNAs (DE-lncRNAs). The Cancer Genome Atlas (TCGA)-OV and ImmPort database were used to obtain immune-related lncRNAs (ir-lncRNAs). Univariate, multivariate, and LASSO Cox regression analyses were performed to construct the prediction model. Kaplan- Meier plotter, Principal Component Analysis (PCA), nomogram, immune function analysis, and therapeutic response were applied with Genomics of Drug Sensitivity in Cancer (GDSC), CIBERSORT, and TCGA databases. The biological functions were evaluated in the CCLE database and OC cells. Results: The RNA-seq defined 186 DE-lncRNAs between PTX-resistant A2780-PTX and PTXsensitive A2780 cells. Through the analysis of the TCGA-OV database, 225 ir-lncRNAs were identified. Analyzing 186 DE-lncRNAs and 225 ir-lncRNAs using univariate, multivariate, and LASSO Cox regression analyses, 9 PTX-resistant immune-related lncRNAs (DEir-lncRNAs) acted as biomarkers were discovered as potential biomarkers in the prediction model. Single-cell RNA sequencing (scRNA-seq) data of OC confirmed the relevance of DEir-lncRNAs in immune responsiveness. Patients with a low prediction score had a promising prognosis, whereas patients with a high prediction score were more prone to evade immunotherapy and chemotherapy and had poor prognosis. Conclusion: The novel prediction model with 9 DEir-lncRNAs is a valuable tool for predicting immunotherapeutic and chemotherapeutic responses and prognosis of patients with OC.

Targeting PNPO to suppress tumor growth via inhibiting autophagic flux and to reverse paclitaxel resistance in ovarian cancer

AbstractOur previous study showed that pyridoxine 5’-phosphate oxidase (PNPO) is a tissue biomarker of ovarian cancer (OC) and has a prognostic implication but detailed mechanisms remain unclear. The current study focused on PNPO-regulated lysosome/autophagy-mediated cellular processes and the potential role of PNPO in chemoresistance. We found that PNPO was overexpressed in OC cells and was a prognostic factor in OC patients. PNPO significantly promoted cell proliferation via the regulation of cyclin B1 and phosphorylated CDK1 and shortened the G2M phase in a cell cycle. Overexpressed PNPO enhanced the biogenesis and perinuclear distribution of lysosomes, promoting the degradation of autophagosomes and boosting the autophagic flux. Further, an autolysosome marker LAMP2 was upregulated in OC cells. Silencing LAMP2 suppressed cell growth and induced cell apoptosis. LAMP2-siRNA blocked PNPO action in OC cells, indicating that the function of PNPO on cellular processes was mediated by LAMP2. These data suggest the existence of the PNPO-LAMP2 axis. Moreover, silencing PNPO suppressed xenographic tumor formation. Chloroquine counteracted the promotion effect of PNPO on autophagic flux and inhibited OC cell survival, facilitating the inhibitory effect of PNPO-shRNA on tumor growth in vivo. Finally, PNPO was overexpressed in paclitaxel-resistant OC cells. PNPO-siRNA enhanced paclitaxel sensitivity in vitro and in vivo. In conclusion, PNPO has a regulatory effect on lysosomal biogenesis that in turn promotes autophagic flux, leading to OC cell proliferation, and tumor formation, and is a paclitaxel-resistant factor. These data imply a potential application by targeting PNPO to suppress tumor growth and reverse PTX resistance in OC.

Insulin-like growth factor 2 mRNA-binding protein 2 is a therapeutic target in ovarian cancer

Ovarian cancer (OC) is a fatal gynecologic disease. The most common treatment for OC patients is surgery combined with chemotherapy but most patients at advanced stages eventually develop relapse due to chemoresistance. This study examined the role and function of insulin-like growth factor 2 mRNA-binding protein 2 (IGF2BP2) in OC. We observed that the expression of IGF2BP2 mRNA and protein was up-regulated in OC cells and tissues using quantitative real-time polymerase chain reaction (qRT-PCR) and western blot, respectively. An increase in IGF2BP2 expression at mRNA and protein levels was verified by the analyses of The Cancer Genome Atlas (TCGA) and Clinical Proteomic Tumor Analysis Consortium (CPTAC), respectively. Gene Expression Omnibus (GEO) and Cancer Cell Line Encyclopedia (CCLE) databases were applied to analyze the expression and clinical value of IGF2BP2. Gene set enrichment analysis (GSEA), Kyoto Encyclopedia of Genes and Genomes (KEGG), and Gene Ontology (GO) analyses explored biological functions and the involvement of IGF2BP2 in cell growth. Indeed, the knockdown of IGF2BP2 resulted in the inhibition of OC cell proliferation evaluated by the Cell Counting Kit-8 assay. Genomic amplification of IGF2BP2 partly accounted for its overexpression. High expression of IGF2BP2 was associated with signal transducer and activator of transcription 1 (STAT1) and drug sensitivity and was correlated with an unfavorable survival outcome in OC patients. Furthermore, the responsiveness of chemotherapy and immunotherapy were analyzed using the “pRRophetic” R package and The Cancer Immune Atlas (TCIA) database, respectively. The low expression of IGF2BP2 was associated with chemoresistance but with high tumor microenvironment scores and tumor-infiltrating immune cells, suggesting that immunotherapy may apply in chemoresistant patients. The alteration of IGF2BP2 expression may respond to chemotherapy and immunotherapy. Thus, IGF2BP2 shows potential as a therapeutic target and diagnostic biomarker for OC.

SLC4A11 is a targetable marker correlated with therapeutic responses in ovarian cancer

Solute carrier family 4 member 11 (SLC4A11) is involved in borate homeostasis, metabolism reprogramming, cell growth, and cell adhesion. However, the biological function of SLC4A11 in ovarian cancer (OC) is still unclear. This study explores the anti-tumor and biological activities of SLC4A11 in OC. The expression and function of SLC4A11 were evaluated in human OC cells and xenograft mice. SLC4A11 expression was evaluated using data from the TCGA-OV, GTEx, and GEO datasets. The genetic status of SLC4A11 was analyzed by the cBioPortal database. The data of expressional abundance, immunochemistry, and immunofluorescence were analyzed through the HPA database. The correlation between SLC4A11 and immune responses was analyzed with the CIBERSORT database, whereas therapeutic responses were analyzed with the CellMiner database. SLC4A11 was found to be highly expressed in OC tissues/cells and had a relationship with an unfavorable prognosis in patients with OC. The overexpressed SLC4A11 promoted OC cell proliferation, migration, and invasion. Reducing SLC4A11 caused the cell cycle arrest at the G0/G1 phase and triggered apoptosis. The in vivo study with a xenographic model revealed that the knockdown of SLC4A11 suppressed tumor growth. Subsequent bioinformatics analyses revealed that SLC4A11 expression was associated with immune responses and therapeutic drug sensitivity. These findings have illustrated the oncogenic role of SLC4A11 in OC. SLC4A11 is overexpressed and is correlated with poor prognosis in OC. SLC4A11 may be a targetable biomarker and has a potential value of application in treating patients with OC.

COL5A1 overexpression correlates with poor prognosis in human cervical cancer

Background Cervical cancer is the most prevalent malignant tumor in women. This study aims to detect collagen type V α1 chain (COL5A1) expression and its clinical relevance in the prognosis of patients with cervical cancer. Methods Cervical cancer tissues and their paired adjacent normal tissues were prepared for tissue microarray. The expression of COL5A1 protein and the scores of the expression were evaluated by immunohistochemistry (IHC) staining. The prognostic value of COL5A1 was analyzed by R software version 4.2.1 with “survival, survminer, ggplot2” packages and Gene Expression Profiling Interactive Analysis (GEPIA). The cBioPortal database was utilized for the analysis of COL5A1 gene mutations. Results COL5A1 protein was overexpressed in human cervical cancer tissues compared to their paired adjacent normal tissues detected by IHC ( P < 0.001). High expression of COL5A1 tends to be in elderly patients with cervical cancer. Survival analyses of clinical data of patients with cervical cancer showed that a high level of COL5A1 expression was significantly correlated with shorter overall survival ( P = 0.031) and disease-free survival ( P = 0.042) of patients. Further analyses of The Cancer Genome Atlas-Cervical Squamous Cell Carcinoma and the GEPIA survival datasets confirmed the association of high COL5A1 expression with poor overall survival of patients ( P = 0.040 and P = 0.018, respectively). The analysis of genomic alterations of COL5A1 using the cBioPortal tool revealed that the COL5A1 gene was altered in 4% of cervical cancer patients and COL5A1 corresponding protein alterations with post-translational modifications were hydroxylation. Conclusion COL5A1 is a tissue biomarker correlated with the poor prognosis of patients with cervical cancer, which may lead to a new clinical application.

Biomarker cystatin B expression correlates with pathogenesis in cervical cancer

Objective Cervical cancer (CC) is one of the most common gynecologic malignancies worldwide. Although rapid improvements have been made regarding its prevention and treatment, little is known about disease pathogenesis and the clinical relevance of reliable biomarkers. The present study evaluated the expression of cystatin B (CSTB) as a potential biomarker of CC. Methods Tissue microarray analysis and immunohistochemical staining were performed to detect CSTB expression, while CSTB mRNA and protein expression levels of freshly isolated CC tissue were measured by quantitative real-time PCR and western blot, respectively. Bioinformatics were used to analyze the CSTB co-expression network and functional enrichments. Results We observed high CSTB mRNA and protein expression levels in CC tissues, which was confirmed by tissue microarray in a comparison with paired adjacent non-cancerous cervical tissue samples. CSTB gene enrichments and associations with co-expressed genes were also observed. Further analysis showed that elevated CSTB expression was associated with pathological progress in CC. Conclusion Our data demonstrate that CSTB has the potential to be used as a tissue biomarker with clinical value in patients with CC, which may aid the development of intervention strategies.

Expression of STAT1 is positively correlated with PD-L1 in human ovarian cancer

Signal transducer and activator of transcription 1 (

A novel homeostatic loop of sorcin drives paclitaxel-resistance and malignant progression via Smad4/ZEB1/miR-142-5p in human ovarian cancer

AbstractThe primary chemotherapy of ovarian cancer (OC) often acquires chemoresistance. Sorcin (SRI), a soluble resistance-related calcium-binding protein, has been reported to be an oncogenic protein in cancer. However, the molecular mechanisms of SRI regulation and the role and aberrant expression of SRI in chemoresistant OC remain unclear. Here, we identified SRI as a key driver of paclitaxel (PTX)-resistance and explored its regulatory mechanism. Using transcriptome profiles, qRT-PCR, proteomics, Western blot, immunohistochemistry, and bioinformatics analyses, we found that SRI was overexpressed in PTX-resistant OC cells and the overexpression of SRI was related to the poor prognosis of patients. SRI was a key molecule required for growth, migration, and PTX-resistance in vitro and in vivo and was involved in epithelial–mesenchymal transition (EMT) and stemness. Mechanistic studies showed that miR-142-5p directly bound to the 3ʹ-UTR of SRI to suppress its expression, whereas a transcription factor zinc-finger E-box binding homeobox 1 (ZEB1) inhibited the transcription of miR-142-5p by directly binding to the E-box fragment in the miR-142 promoter region. Furthermore, ZEB1 was negatively regulated by SRI which physically interacted with Smad4 to block its translocation from the cytosol to the nucleus. Taken together, our findings unveil a novel homeostatic loop of SRI that drives the PTX-resistance and malignant progression via Smad4/ZEB1/miR-142-5p in human OC. Targeting this SRI/Smad4/ZEB1/miR-142-5p loop may reverse the PTX-resistance.

Overexpressed COL5A1 is correlated with tumor progression, paclitaxel resistance, and tumor‐infiltrating immune cells in ovarian cancer

AbstractOvarian cancer (OC) remains the leading cause of cancer‐related death among gynecological cancers. The present study examined the role of collagen type V alpha 1 (COL5A1) and the characteristics of COL5A1 as an oncogenic protein in OC. The association of COL5A1 with paclitaxel (PTX)‐resistance and stemness in OC was also studied and the multidatabase and big data analyses of the prognostic value, coexpression network, genetic alterations, and tumor‐infiltrating immune cells of COL5A1 were elucidated. We found that COL5A1 expression was high in OC cells and tissues. Knockdown of COL5A1 inhibited the proliferation and migration of OC cells. Further study also showed that COL5A1 was overexpressed in PTX‐resistant OC cells compared to respective PTX‐sensitive cells. Additionally, COL5A1 was more enriched in OC stem cell‐like cells. Silencing COL5A1 expression decreased the OC cell resistance to PTX and inhibited the ability of OC‐spheroid formation. Survival analysis predicted that the elevated COL5A1 expression was associated with a worse survival outcome and correlated to the tumor stage of OC patients. The estimating relative subsets of RNA transcripts (CIBERSORT) algorithm analysis also unveiled the correlation of several tumor‐infiltrating immune cells with the expression of COL5A1. Taken together, our data demonstrate that COL5A1 is a biomarker to predict OC progression and PTX‐resistance and represents a promising target for OC treatment.

Lipid-coated albumin-paclitaxel nanoparticles loaded with sorcin-siRNA reverse cancer chemoresistance via restoring intracellular calcium ion homeostasis

AbstractChemoresistance is often a cause of the failure of chemotherapy in cancer treatment. Sorcin (SRI) is a soluble resistance-related calcium-binding protein involved in chemoresistant processes and is overexpressed in many chemoresistant cancer cells, including paclitaxel (PTX)-resistant ovarian cancer. Increased SRI can reduce the concentration of calcium ions in the cytosol and mitochondria and the decrease of calcium ion concentration prevents the occurrence of apoptosis. Here we examined the SRI expression in multiple cancers using a human TissueArray and found that SRI expression was significantly higher in malignant tumor tissues. Furthermore, SRI was overexpressed, while intracellular calcium concentration was decreased, in chemoresistant cancer cells. To restore intracellular calcium homeostasis and overcome chemoresistance, we developed lipid-coated albumin-PTX nanoparticles loaded with SRI-siRNA (LANP-PTX-siSRI) for PTX and SRI-siRNA co-delivery. LANP-PTX-siSRI had dual-target roles in the regulation of SRI and the delivery of PTX into chemoresistant cells. The LANP-PTX-siSRI inhibited the expression of SRI and enhanced intracellular calcium, leading to the induction of apoptosis and the inhibition of the growth of PTX-resistant cancer cells in vitro and in vivo. In addition, the mechanism study revealed that the overexpression of SRI was associated with an impaired TGF-β signaling pathway. The administration of TGF-β1 inhibited two calcium-binding proteins SRI and S100A14. In conclusion, our data unveil that restoring intracellular calcium ion homeostasis via reducing SRI expression can reverse chemoresistance. Thus, the fabricated LANP-PTX-siSRI has a potentially therapeutical application.