• The Korean Journal of Physiology and Pharmacology
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• v.27 no.2
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• pp.131-141
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• 2023

Compelling evidence has demonstrated the critical role of circular RNAs (circRNAs) during lung adenocarcinoma (LUAD) progression. Herein, we explored a novel circRNA, circ_0129047, and detailed its mechanism of action. The expression of circ 0129047, microRNA-665 (miR-665), and protein tyrosine phosphatase receptor type B (PTPRB) in LUAD tissues and cells was determined using reverse transcription quantitative polymerase chain reaction and Western blotting. Cell Counting Kit8 and colony formation assays were conducted to detect LUAD cell proliferation, and western blotting was performed to quantify apoptosis-related proteins (Bcl2 and Bax). Luciferase reporter and RNA immunoprecipitation assays were used to validate the predicted interaction between miR-665 and circ_0129047 or PTPRB. A xenograft assay was used for the in vivo experiments. Circ_0129047 and PTPRB were downregulated in LUAD tissues and cells, whereas miR-665 expression was upregulated. Overexpression of circ_0129047 suppresses LUAD growth in vivo and in vitro. Circ_0129047 is the target of miR-665, and the miR-665 mimic ablated the antiproliferative and pro-apoptotic phenotypes of LUAD cells by circ_0129047 augmentation. MiR-665 targets the 3'UTR of PTPRB and downregulates PTPRB expression. PTPRB overexpression offsets the pro-proliferative potential of miR-665 in LUAD cells. Circ_0129047 sequestered miR-665 and upregulated PTPRB expression, thereby reducing LUAD progression, suggesting a promising approach for preventing LUAD.

• Journal of Microbiology and Biotechnology
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• v.29 no.4
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• pp.645-650
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• 2019

Brown adipocytes have an important role in the regulation of energy balance through uncoupling protein-1 (UCP-1)-mediated nonshivering thermogenesis. Although brown adipocytes have been highlighted as a new therapeutic target for the treatment of metabolic diseases, such as obesity and type II diabetes in adult humans, the molecular mechanism underlying brown adipogenesis is not fully understood. We recently found that protein tyrosine phosphatase receptor type B (PTPRB) expression dramatically decreased during brown adipogenic differentiation. In this study, we investigated the functional roles of PTPRB and its regulatory mechanism during brown adipocyte differentiation. Ectopic expression of PTPRB led to a reduced brown adipocyte differentiation by suppressing the tyrosine phosphorylation of VEGFR2, whereas a catalytic inactive PTPRB mutant showed no effects on differentiation and phosphorylation. Consistently, the expression of brown adipocyte-related genes, such as UCP-1, $PGC-1{\alpha}$, PRDM16, $PPAR-{\gamma}$, and CIDEA, were significantly inhibited by PTPRB overexpression. Overall, these results suggest that PTPRB functions as a negative regulator of brown adipocyte differentiation through its phosphatase activity-dependent mechanism and may be used as a target protein for the regulation of obesity and type II diabetes.