It is unclear whether both CD1 and CD2 of A3B can deaminate C and mC. We showed that only CD2 is active, and has weak mC deaminating activity. We successfully engineered A3BCD2 to gain over 100-fold higher mC deamination activity.
Long non-coding RNA (lncRNA) X-inactive specific transcript (XIST) is involved in the development and progression of many tumors. In this study, XIST was specifically upregulated in pancreatic carcinoma tissues and cell lines; a higher XIST expression was correlated to poorer clinicopathologic features. After XIST knockdown, the proliferation of PC cell lines was suppressed and cell cycle stagnated in G1 phase; XIST knockdown also reduced the protein levels of inhibitor of apoptosis-stimulating protein of p53 (iASPP) and Cyclin-dependent kinase 1 (CDK1), increased the protein level of P21, a potent CDK inhibitor. In PC cell lines, XIST and miR-140/miR-124, two tumor-associated miRNAs, could inversely regulate each other, respectively; miR-140/miR-124 could bind to XIST and the 3’UTR of PPP1R13L, respectively. XIST and miR-140/miR-124 exerted opposite effects on iASPP, CDK1, P21 and P27 proteins; whereas the effects of LV-sh-XIST on the indicated protein levels could be partially reversed by miR-140 and/or miR-124 inhibitor. In PC tissues, miR-140 and miR-124 expression was down-regulated, iASPP and CDK1 mRNA expression was up-regulated. XIST positively correlated with iASPP and CDK1, inversely correlated with miR-140 and miR-124, respectively. Taken together, our data indicated that XIST might be an oncogenic lncRNA that promoted proliferation of PC cell line through inhibiting miR-140/miR-124 expression and promoting cell cycle-related factor expression, and could be regarded as a therapeutic target in human pancreatic carcinoma.
MicroRNAs are ∼22 nucleotide RNAs processed from RNA hairpin structures that play important roles in regulating protein expression level via binding to mRNA, either suppressing its translation or speeding up its degradation. In humans, they regulate most protein-coding genes, including genes important in cancer and other diseases. In this study, the expression of microRNA-140 (miR-140) was demonstrated to be significantly suppressed in pancreatic duct adenocarcinoma specimens and cell lines, compared with their adjacent normal tissues. With the help of bioinformatics analysis, inhibitor of apoptosis-stimulating protein of p53 (iASPP) was identified to be a direct target of miR-140, and luciferase reporter experiment confirmed this discovery. Overexpression of miR-140 decreases the protein expressions of iASPP, ΔNp63, MMP2, and MMP9. Growth and invasion of PANC-1 cells were attenuated by overexpression of miR-140 in vitro. The suppressive effect of miR-140 on PANC-1 cell line could be partly balanced out by manual overexpression of iASPP. Above all, these findings provided insights into the functional mechanism of miR-140, suggested that the miR-140/iASPP axis may interfere with the proliferative and invasive property of pancreatic duct adenocarcinoma cells, and indicated that miR-140 could be a potential therapeutic target for pancreatic duct adenocarcinoma.
Background
Cuproptosis is a new type of copper-induced cell death that is characterized by the aggregation of lipoylated tricarboxylic acid (TCA) cycle proteins. However, its role in hepatocellular carcinoma (HCC) remains unclear. The goal of this research is to develop a cuproptosis-related signature predicting the prognosis of HCC.
Methods
The cuproptosis-related genes were defined using Pearson correlation coefficients. LASSO-Cox regression analysis was used to evaluate the prognostic values of cuproptosis-related genes to construct a cuproptosis-related prognostic model. The immune microenvironment analysis was performed by “ssGSEA” to reveal the associated immune cell infiltration patterns with the cuproptosis-related genes signature. The expression levels of one of the prognostic genes PDXK were then verified in HCC samples by Western Blot and immunohistochemistry. The potential roles of target genes in cuproptosis were further explored during in-vitro experiments.
Results
A total of 136 cuproptosis-related genes were discovered using Pearson correlation analysis in HCC. A cuproptosis-related signature that included 5 cuproptosis-related genes (PDXK, HPN, SLC25A28, RNFT1, CLEC3B) was established in the TCGA-LIHC training cohort. TCGA validation cohort and another two external validation cohorts confirmed the robustness of the signature’s predictive value. Moreover, a nomogram using the risk score was created to best predict the survival of HCC patients. The immune microenvironment analysis revealed distinct immune infiltrations patterns between different risk groups based on the signature model. Furthermore, the upregulation of PDXK was confirmed in HCC tumor tissues in 30 clinical HCC specimens. The knockdown of PDXK reduced the proliferation, migration and invasion of HCC cells. Besides, the expression of PDXK was upregulated after the induction of cuproptosis by elesclomol–CuCL2, which could be suppressed when pretreated with a copper ion chelator. And PDXK deficiency increased the sensitivity of HCC cells to cuproptosis inducer.
Conclusion
Our study identified a new cuproptosis-related gene signature that could predict the prognosis of HCC patient. Besides, the upregulated PDXK could promote the proliferation and metastasis of HCC. And PDXK deficiency facilities cuproptosis in HCC. Therefore, these fundings highlighted that PDXK might serve as a potential diagnostic and therapeutic target for HCC.
The incidence and mortality of papillary thyroid cancer (PTC) have steadily increased. Although conventional therapies are very effective toward differentiated PTC patients, very limited therapeutic options are applicable to those patients with distant metastases. Therefore, better understanding of the molecular biology of metastatic PTC helps identify novel targets and facilitates the development of new therapies. In this study, we first found that testicular orphan receptor 4 (TR4) was significantly increased in PTC tumors spreading to lymph nodes compared to the paired primary tumors. Experimental evidence suggested that TR4 drove PTC progression via promoting its cell invasion and cell migration. Mechanistically, TR4 transcriptionally regulated the expression level of circ-filamin A (FLNA), which competed with matrix metalloproteinase 9 (MMP9) for microRNA (miR)-149-5p binding and led to an increased protein level of MMP9. Interruption assays with various gene manipulations verified that the TR4/circ-FLNA/miR-149-5p/MMP9 signaling axis played a central role in cell invasion and cell migration of PTC cells. Moreover, a xenografted mouse model also confirmed that the TR4/circ-FLNA signal promoted PTC tumor growth. Overall, our study pinpoints the oncogenic role of TR4 in PTC development, and the targeting of TR4/circ-FLNA/miR-149-5p/MMP9 signaling may be an alternative option for metastatic PTC patients.
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