PYCR2 promotes growth and aerobic glycolysis in human liver cancer by regulating the AKT signaling pathway

Cardiac endothelial ischemia/reperfusion injury-derived protein damage-associated molecular patterns disrupt the integrity of the endothelial barrier

Human cardiac microvascular endothelial cells (HCMECs) are sensitive to ischemia and vulnerable to damage during reperfusion. The release of damage-associated molecular patterns (DAMPs) during reperfusion induces additional tissue damage. The current study aimed to identify early protein DAMPs in human cardiac microvascular endothelial cells subjected to ischemia-reperfusion injury (IRI) using a proteomic approach and their effect on endothelial cell injury. HCMECs were subjected to 60 min of simulated ischemia and 6 h of reperfusion, which can cause lethal damage. DAMPs in the culture media were subjected to liquid chromatography-tandem mass spectrometry proteomic analysis. The cells were treated with endothelial IRI-derived DAMP medium for 24 h. Endothelial injury was assessed by measuring lactate dehydrogenase activity, morphological features, and the expression of endothelial cadherin, nitric oxide synthase (eNOS), and caveolin-1. The top two upregulated proteins, DNAJ homolog subfamily B member 11 and pyrroline-5-carboxylate reductase 2, are promising and sensitive predictors of cardiac microvascular endothelial damage. HCMECs expose to endothelial IRI-derived DAMP, the lactate dehydrogenase activity was significantly increased compared with the control group (10.15 ± 1.03 vs 17.67 ± 1.19, respectively). Following treatment with endothelial IRI-derived DAMPs, actin-filament dysregulation, and downregulation of vascular endothelial cadherin, caveolin-1, and eNOS expressions were observed, along with cell death. In conclusion, the early protein DAMPs released during cardiac microvascular endothelial IRI could serve as novel candidate biomarkers for acute myocardial IRI. Distinct features of impaired plasma membrane integrity can help identify therapeutic targets to mitigate the detrimental consequences mediated of endothelial IRI-derived DAMPs.

PYCR2, induced by c-Myc, promotes the invasiveness and metastasis of breast cancer by activating AKT signalling pathway

BACKGROUND

Pyrroline-5-carboxylate reductase 2 (PYCR2) expression is aberrantly upregulated in colon cancer. However, the functions and underlying mechanisms of PYCR2 in breast cancer remain elusive. The primary objective of the present study was to elucidate the function of PYCR2 in breast cancer and investigate whether PYCR2 may be transcriptionally regulated by c-Myc to activate the AKT signaling pathway.

METHODS

Immunohistochemical analysis was performed to examine the expression of PYCR2 in breast cancer and adjacent non-cancerous tissues. Western blot and RT-qPCR were utilized to detect PYCR2 expression in breast cancer cells. Cellular functionalities were evaluated through Transwell assays in vitro and lung metastasis formation assays in vivo. Moreover, the impact of PYCR2 on the activation of AKT signaling was determined through western blot and immunohistochemistry analysis. The transcriptional regulation of PYCR2 expression by c-Myc was evaluated via both western blot analysis and luciferase gene reporter assay.

RESULTS

PYCR2 overexpression was noted in breast cancer. Silencing PYCR2 expression attenuated the invasive and metastatic abilities of breast cancer cells. Furthermore, the activation of the AKT signaling pathway is indispensable for the promotion of invasion and metastasis mediated by PYCR2. Lastly, the binding of c-Myc to the promoter sequence of PYCR2 resulted in the upregulation of PYCR2 transcription.

CONCLUSION

Taken together, these results indicate that PYCR2 is transcriptionally regulated by c-Myc and promotes invasion and metastasis in breast cancer through the activation of the AKT pathway.