VO-Ohpic trihydrate

VO-Ohpic is a highly selective small-molecule inhibitor of phosphatase and tensin homologue deleted on chromosome 10 (PTEN) with IC50 value of 35 nM [1].
Many research studies show that the lipid phosphatase activity of PTEN has certain cellular impacts, such as inhibition of proliferation, survival and regulation of insulin signaling. Meanwhile, the inhibition of PTEN’s lipid phosphatase activity increases glucose uptake triggered by the increase of PtdIns (3, 4, 5) P3. These suggest that small-molecule inhibitor of PTEN may have the potential of enhancing insulin sensitivity and overcoming insulin resistance, which would be beneficial for the development of diabetes therapeutics. VO-Ohpic is a specific vanadium-based inhibitor screened out from a range of synthesized vanadates and bpV complexes. [1]
In vitro, VO-Ohpic inhibited the lipid phosphatase activity of recombinant PTEN with IC50 value of 35 nM. It was highly selective against PTEN over other recombinant phosphatases including CBPs, SopB, myotubularin, SAC1 and PTP-β. It inhibited CBPs and SopB with IC50 values in micromolar range and high nanomolar range, respectively. In NIH 3T3 and L1 fibroblasts, VO-Ohpic dose-dependently increased Akt phosphorylation at site Ser473 and Thr308. This effect reached saturation at 75 nM. VO-OHpic had no effect on insulin-stimulated tyrosine phosphorylation at concentrations up to 10 μM. Besides that, VO-Ohpic treatment was found to cause the functional activation of Akt, demonstrated by a corresponding reduction of the transcriptional activity of FoxO3a [1].
In mice bearing MDA PCa-2b cell xenografts, administration of VO-Ohpic showed significant tumor growth suppression. Moreover, long term treatment of VO-Ohpic resulted in an increased survival of the treated animals. The tumors treated with VO-Ohpic displayed increased β-gal staining and decreased Ki-67 staining compared with the untreated control tumors [2].
References:
[1] Rosivatz E, Matthews J G, McDonald N Q, et al. A small-molecule inhibitor for phosphatase and tensin homologue deleted on chromosome 10 (PTEN). ACS chemical biology, 2006, 1(12): 780-790.
[2] Alimonti A, Nardella C, Chen Z, et al. A novel type of cellular senescence that can be enhanced in mouse models and human tumor xenografts to suppress prostate tumorigenesis. The Journal of clinical investigation, 2010, 120(3): 681.

MiR-21 promotes pterygium cell proliferation through the PTEN/AKT pathway.[Pubmed:30967746]

Mol Vis. 2018 Jul 23;24:485-494. eCollection 2018.

Purpose: To evaluate the effect of the overexpression of miR-21 on the properties of pterygium and examine whether miR-21 promotes the proliferation of pterygium cells through targeting the PTEN/AKT signaling pathway. Methods: Information regarding patient gender, age, and pterygium severity was gathered. Expression of miR-21 was obtained through examination of excised pterygium tissues and superior conjunctiva tissues with real-time PCR. Human pterygium fibroblasts (HPFs) were obtained from pterygium surgery and subjected to primary culture. The HPF cell lines were divided into a negative control group, an miR-21 inhibitor group, and an miR-21 inhibitor + VO-Ohpic trihydrate group, and then the cell viability and apoptosis and the expression of PTEN and AKT were examined. Results: Fifty-eight subjects with unilateral primary pterygium were included. An increase in the miR-21 levels in pterygium tissue was evident compared with that in the paired normal conjunctival tissues (independent-samples t test, p<0.01). As the severity of the pterygium increased, the miR-21 levels increased (p=0.004, rs=0.373, Spearman's rank correlation coefficient). The miR-21 inhibitor suppressed the proliferation and induced apoptosis of HPF cells through increasing the PTEN expression, and further decreasing the expression of p-AKT, which could be reversed by the PTEN inhibitor VO-Ohpic trihydrate. Conclusions: Aberrant miR-21 overexpression in the pterygium could target PTEN, which contributes to abnormal proliferation of the HPF cells through depressing the PTEN/AKT pathway. The results also suggested the potential of miR-21 and the PTEN/AKT pathway as a novel therapeutic strategy for pterygium.