Impact of BSG/CD147 gene expression on diagnostic, prognostic and therapeutic strategies towards malignant cancers and possible susceptibility to SARS-CoV-2.

BACKGROUND: BSG (CD147) is a member of the immunoglobulin superfamily that shows roles for potential prognostics and therapeutics for metastatic cancers and SARS-CoV-2 invasion for COVID-19. The susceptibility of malignant cancers to SARS-CoV-2 as well as the correlations between disease outcome and BSG expression in tumor tissues have not been studied in depth. METHODS: In this study, we explored the BSG expression profile, survival correlation, DNA methylation, mutation, diagnostics, prognostics, and tumor-infiltrating lymphocytes (TILs) from different types of cancer tissues with corresponding healthy tissues. In vitro studies for cordycepin (CD), N6-(2-hydroxyethyl) adenosine (HEA), N6, N6-dimethyladenosine (m62A) and 5'-uridylic acid (UMP) on BSG expression were also conducted. RESULTS: We revealed that BSG is conserved among different species, and significantly upregulated in seven tumor types, including ACC, ESCA, KICH, LIHC, PAAD, SKCM and THYM, compared with matched normal tissues, highlighting the susceptibility of these cancer patients to SARS-CoV-2 invasion, COVID-19 severity and progression of malignant cancers. High expression in BSG was significantly correlated with a short OS in LGG, LIHC and OV patients, but a long OS in KIRP patients. Methylation statuses in the BSG promoter were significantly higher in BRCA, HNSC, KIRC, KIRP, LUSC, PAAD, and PRAD tumor tissues, but lower in READ. Four CpGs in the BSG genome were identified as potential DNA methylation biomarkers which could be used to predict malignant cancers from normal individuals. Furthermore, a total of 65 mutation types were found, in which SARC showed the highest mutation frequency (7.84%) and THYM the lowest (0.2%). Surprisingly, both for disease-free and progression-free survival in pan-cancers were significantly reduced after BSG mutations. Additionally, a correlation between BSG expression and immune lymphocytes of CD56bright natural killer cell, CD56dim natural killer cell and monocytes, MHC molecules of HLA-A, HLA-B, HLA-C and TAPBP, immunoinhibitor of PVR, PVRL2, and immunostimulators of TNFRSF14, TNFRSF18, TNFRSF25, and TNFSF9, was revealed in most cancer types. Moreover, BSG expression was downregulated by CD, HEA, m62A or UMP in cancer cell lines, suggesting therapeutic potentials for interfering entry of SARS-CoV-2. CONCLUSIONS: Altogether, our study highlights the values of targeting BSG for diagnostic, prognostic and therapeutic strategies to fight malignant cancers and COVID-19. Small molecules CD, HEA, m62A and UMP imply therapeutic potentials in interfering with entry of SARS-CoV-2 and progression of malignant cancers.

COVID-19 receptor and malignant cancers: Association of CTSL expression with susceptibility to SARS-CoV-2.

CTSL is expressed by cancerous tissues and encodes a lysosomal cysteine proteinase that regulates cancer progression and SARS-CoV-2 entry. Therefore, it is critical to predict the susceptibility of cancer patients for SARS-CoV-2 and evaluate the correlation between disease outcomes and the expression of CTSL in malignant cancer tissues. In the current study, we analyzed CTSL expression, mutation rate, survival and COVID-19 disease outcomes in cancer and normal tissues, using online databases. We also performed immunohistochemistry (IHC) to test CTSL expression and western blot to monitor its regulation by cordycepin (CD), and N6, N6-dimethyladenosine (m62A), respectively. We found that CTSL is conserved across different species, and highly expressed in both normal and cancer tissues from human, as compared to ACE2 or other proteinases/proteases. Additionally, the expression of CTSL protein was the highest in the lung tissue. We show that the mRNA expression of CTSL is 66.4-fold higher in normal lungs and 54.8-fold higher in cancer tissues, as compared to ACE2 mRNA expression in the respective tissues. Compared to other proteases/proteinases/convertases such as TMPRSS2 and FURIN, the expression of CTSL was higher in both normal lungs and lung cancer samples. All these data indicate that CTSL might play an important role in COVID-19 pathogenesis in normal and cancer tissues of the lungs. Additionally, the CTSL-002 isoform containing both the inhibitor_I29 and Peptidase_C1 domains was highly prevalent in all cancers, suggesting its potential role in tumor progression and SARS-CoV-2 entry in multiple types of cancers. Further analysis of the expression of CTSL mutant showed a correlation with FURIN and TMPRSS2, suggesting a potential role of CTSL mutations in modulating SARS-CoV-2 entry in cancers. Moreover, high expression of CTSL significantly correlated with a short overall survival (OS) in lung cancer and glioma. Thus, CTSL might play a major role in the susceptibility of lung cancer and glioma patients to SARS-CoV-2 uptake and COVID-19 severity. Furthermore, CD or m62A inhibited CTSL expression in the cancer cell lines A549, MDA-MB-231, and/or PC3 in a dose dependent manner. In conclusion, we show that CTSL is highly expressed in normal tissues and increased in most cancers, and CD or m62A could inhibit its expression, suggesting the therapeutic potential of targeting CTSL for cancer and COVID-19 treatment.

COVID-19 disease and malignant cancers: The impact for the furin gene expression in susceptibility to SARS-CoV-2.

Furin is a proprotein convertase that activates different kinds of regulatory proteins, including SARS-CoV-2 spike protein which contains an additional furin-specific cleavage site. It is essential in predicting cancer patients' susceptibility to SARS-CoV-2 and the disease outcomes due to varying furin expressions in tumor tissues. In this study, we analyzed furin's expression, methylation, mutation rate, functional enrichment, survival rate and COVID-19 outcomes in normal and cancer tissues using online databases, and our IHC. As a result, furin presented with biased expression profiles in normal tissues, showing 12.25-fold higher than ACE2 in the lungs. The furin expression in tumors were significantly increased in ESCA and TGCT, and decreased in DLBC and THYM, indicating furin may play critical mechanistic functions in COVID-19 viral entry into cells in these cancer patients. Line with furin over/downexpression, furin promoter hypo-/hyper-methylation may be the regulatory cause of disease and lead to pathogenesis of ESCA and THYM. Furthermore, presence of FURIN-201 isoform with functional domains (P_proprotein, Peptidase_S8 and S8_pro-domain) is highest in all cancer types in comparison to other isoforms, demonstrating its use in tumorigenesis and SARS-Cov-2 entry into tumor tissues. Furin mutation frequency was highest in UCES, and its mutation might elevate ACE2 expression in LUAD and UCEC, reduce ACE2 expression in COAD, elevate HSPA5 expression in PAAD, and elevate TMPRSS2 expression in BRCA. These results showed that furin mutations mostly increased expression of ACE2, HSPA5, and TMPRSS2 in certain cancers, indicating furin mutations might facilitate COVID-19 cell entry in cancer patients. In addition, high expression of furin was significantly inversely correlated with long overall survival (OS) in LGG and correlated with long OS in COAD and KIRC, indicating that it could be used as a favorable prognostic marker for cancer patients' survival. GO and KEGG demonstrated that furin was mostly enriched in genes for metabolic and biosynthetic processes, retinal dehydrogenase activity, tRNA methyltransferase activity, and genes involving COVID-19, further supporting its role in COVID-19 and cancer metabolism. Moreover, Cordycepin (CD) inhibited furin expression in a dosage dependent manner. Altogether, furin's high expression might not only implies increased susceptibility to SARS-CoV-2 and higher severity of COVID-19 symptoms in cancer patients, but also it highlights the need for cancer treatment and therapy during the COVID-19 pandemic. CD might have a potential to develop an anti-SARS-CoV-2 drug through inhibiting furin expression.