Emerging role of caldesmon in cancer:A potential biomarker for colorectal cancer and other cancers

Colorectal cancer(CRC) is a devastating disease, mainly because of metastasis. As a result, there is a need to better understand the molecular basis of invasion and metastasis and to identify new biomarkers and therapeutic targets to aid in managing these tumors. The actin cytoskeleton and actin-binding proteins are known to play an important role in the process of cancer metastasis because they control and execute essential steps in cell motility and contractility as well as cell division. Caldesmon(CaD) is an actin-binding protein encoded by the CALD1 gene as multiple transcripts that mainly encode two protein isoforms: High-molecular-weight CaD, expressed in smooth muscle, and low-molecular weight CaD(l-CaD), expressed in nonsmooth muscle cells. According to our comprehensive review of the literature, CaD, particularly l-CaD, plays a key role in the development, metastasis, and resistance to chemoradiotherapy in colorectal, breast, and urinary bladder cancers and gliomas, among other malignancies. CaD is involved in many aspects of the carcinogenic hallmarks, including epithelial mesenchymal transition via transforming growth factor-beta signaling, angiogenesis, resistance to hormonal therapy, and immune evasion. Recent data show that CaD is expressed in tumor cells as well as in stromal cells, such as cancerassociated fibroblasts, where it modulates the tumor microenvironment to favor the tumor. Interestingly, CaD undergoes selective tumor-specific splicing, and the resulting isoforms are generally not expressed in normal tissues, making these transcripts ideal targets for drug design. In this review, we will analyze these features of CaD with a focus on CRC and show how the currently available data qualify CaD as a potential candidate for targeted therapy in addition to its role in the diagnosis and prognosis of cancer.

Insight into molecular mechanisms underlying hepatic dysfunction in severe COVID-19 patients using systems biology

BACKGROUND The coronavirus disease 2019(COVID-19),a pandemic contributing to more than 105 million cases and more than 2.3 million deaths worldwide,was described to be frequently accompanied by extrapulmonary manifestations,including liver dysfunction.Liver dysfunction and elevated liver enzymes were observed in about 53%of COVID-19 patients.AIM To gain insight into transcriptional abnormalities in liver tissue of severe COVID-19 patients that may result in liver dysfunction.METHODS The transcriptome of liver autopsy samples from severe COVID-19 patients against those of non-COVID donors was analyzed.Differentially expressed genes were identified from normalized RNA-seq data and analyzed for the enrichment of functional clusters and pathways.The differentially expressed genes were then compared against the genetic signatures of liver diseases including cirrhosis,fibrosis,non-alcoholic fatty liver disease(NAFLD),and hepatitis A/B/C.Gene expression of some differentially expressed genes was assessed in the blood samples of severe COVID-19 patients with liver dysfunction using qRT-PCR.RESULTS Analysis of the differential transcriptome of the liver tissue of severe COVID-19 patients revealed a significant upregulation of transcripts implicated in tissue remodeling including G-coupled protein receptors family genes,DNAJB1,IGF2,EGFR,and HDGF.Concordantly,the differential transcriptome of severe COVID-19 liver tissues substantially overlapped with the disease signature of liver diseases characterized with pathological tissue remodeling(liver cirrhosis,Fibrosis,NAFLD,and hepatitis A/B/C).Moreover,we observed a significant suppression of transcripts implicated in metabolic pathways as well as mitochondrial function,including cytochrome P450 family members,ACAD11,CIDEB,GNMT,and GPAM.Consequently,drug and xenobiotics metabolism pathways are significantly suppressed suggesting a decrease in liver detoxification capacity.In correspondence with the RNA-seq data analysis,we observed a significant upregulation of DNAJB1 and HSP90AB1 as well as significant downregulation of CYP39A1 in the blood plasma of severe COVID-19 patients with liver dysfunction.CONCLUSION Severe COVID-19 patients appear to experience significant transcriptional shift that may ensue tissue remodeling,mitochondrial dysfunction and lower hepatic detoxification resulting in the clinically observed liver dysfunction.