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Baicalein is a flavonoid with excellent oxidant scavenging capability. It has been reported to protect against a variety of oxidative injuries including ischemia/reperfusion (I/R). However, the optimal treatment strategy for I/R injury and the protective mechanisms are not fully understood. In this study we employed an established chick cardiomyocyte model of I/R and investigated the effects of three baicalein treatment strategies on reactive oxygen species (ROS) scavenging, nitric oxide (NO) production and cell viability. The molecular signaling pathways were also explored. Compared to the I/R control (cell death 52.2$\pm$2.0%), baicalein preventive treatment (25$\mu$M, pretreated for 72h and continued through I/R) conferred the best protection (19.5$\pm$3.9%, $p<0.001$), followed by I/R treatment (treated during I/R) and reperfusion treatment (treated at reperfusion only). Preventive and I/R treatments almost completely abolished ROS generation during both ischemic and reperfusion phases, and increased NO production and Akt phosphorylation. Reperfusion treatment reduced the ROS burst in the early reperfusion phase only, and had no effect on NO production and Akt activation. Further, the phosphorylation of phosphatase and tensin homolog (PTEN), a phosphatase negatively regulating Akt activation, was significantly increased by baicalein preventive treatment and slightly by the I/R treatment. PTEN protein expression was reduced in the same trend accordingly. Baicalein reperfusion treatment had no effects on PTEN phosphorylation and expression. Our results indicate that baicalein preventive treatment confers optimal cardioprotection against I/R injury, and this protection involves effective oxidant scavenging and the activation of PTEN/Akt/NO pathway.

Hexokinase 2 (HK2), the first glycolytic rate-limiting enzyme, is closely correlated with the occurrence and progression of tumors. Effective therapeutic agents targeting HK2 are urgently needed. Bergenin has exhibited various pharmacological activities, such as antitumor properties. However, the effects of bergenin on the abnormal glucose metabolism of cancer cells are yet unclear. In this study, HK2 was overexpressed in OSCC tissues, and the depletion of HK2 inhibited the growth of OSCC cells in vitro and in vivo. Moreover, these results showed that the natural compound, bergenin, exerted a robust antitumor effect on OSCC cells. Bergenin inhibited cancer cell proliferation, suppressed glycolysis, and induced intrinsic apoptosis in OSCC cells by downregulating HK2. Notably, bergenin restored the antitumor efficacy of irradiation in the radioresistant OSCC cells. A mechanistic study revealed that bergenin upregulated the protein level of phosphatase and the tensin homolog deleted on chromosome 10 (PTEN) by enhancing the interaction between PTEN and ubiquitin-specific protease 13 (USP13) and stabilizing PTEN; this eventually inhibited AKT phosphorylation and HK2 expression. Bergenin was identified as a novel therapeutic agent against glycolysis to inhibit OSCC and overcome radioresistance. Targeting PTEN/AKT/HK2 signaling could be a promising option for clinical OSCC treatment.

Phosphatase and tensin homolog deleted on chromosome 10 (PTEN), a tumor suppressor protein with dual phosphatase activity, is found to be frequently mutated in various cancers. PTEN is post-translationally modulated at various amino acid residues which are crucial for sub-cellular localization as well as its catalytic functions rendering genomic stability. Recent reports suggest that PTEN also acts as a DNA repair protein. But how post-translational modulation of PTEN affects cytological damage and aneuploidy is not studied in detail. Here, we focus on the role of sumoylation of PTEN in context with DNA damage induced cytological damage like micronucleus (MNi), nuclear bud (NB), and nuclear bridge formation. Our data suggest that wild type PTEN but not sumo-dead PTEN significantly reduces cytological damage in PTEN mutant PC3 cells. In case of sumo-dead PTEN, the cytological parameters are increased during 24h recovery time point after DNA damage. Next, we measured the effectiveness of the sumo-dead (PTEN-K254R) mutant on aneuploidy, where we found that sumoylation is essential for maintaining chromosome number. As chromosome number variation in daughter cell is due to multiple spindle pole formation, we qualitatively and quantitatively evaluate the $\gamma$ tubulin pole formation in PTEN-K254R clone transfected cells. We found aberrant pole formation is significantly increased in PTEN-K254R transfected cells compared to wild-type PTEN. Further depletion of sumoylation activity of PTEN increases the expression of phosphorylated form of Aurora kinase A (AURKA) (T288) and PLK1 (T210) proteins with or without nocodazole, a microtubule depolymerizing agent compared to cells expressing wild-type PTEN. Thus, sumoylation of PTEN is essential for maintaining genomic stability.

Background and Aim: Before being applied on the clinical settings, the establishment of ovarian tissue cryopreservation and transplantation process should be optimum. The vascularization after transplant is depended on the ovarian tissue size, which influence the follicular recruitment. It may then affect the post-transplantation survival.

Methods: On chorionic-allantoic membrane (CAM) of 8-days-old, fertilized eggs, goat ovarian tissue samples (Capra hircus) were split into pre- and post-transplantation groups. Each group was subsequently divided into 2.5×2.5×1, 5×5×1, and 10×10×1 mm size. Vascularization density and vascularization surface area was analysed and correlated with PTEN protein expressions.

Results: Pre- and post-transplantation samples were taken from a total of 36 strips of ovarian tissue. The vascularization density was found to be the highest in the 2.5×2.5×1 mm transplantation samples compared to the pre-transplantation samples (9.54±3.2; 15.46±1.85; P<0,05). Meanwhile the vascularization surface area was also significantly higher after transplantation regardless the size of ovarian tissue (P<0,05). Interestingly, the vascularization surface area was observed to be significantly higher in the cortex area adhered to CAM compared to more distant than the CAM. To magnify the vascularization results, in the 2.5×2.5×1 mm transplantation sample, it was shown that the higher PTEN expression after transplantation. Concurrently in the 10×10×1 mm transplantation, PTEN protein expressions were significantly lower in primordial follicles after transplantation (P<0.05). These results were also mutual for total number of primordial follicles in 2.5×2.5×1 mm, which were higher after transplantation (mean rank 11.92±2.56) compared to the other size groups (10.88±1.48; 9.72±6.36).

Conclusions: The most vascularized ovarian tissue samples were found to be 2.5×2.5×1 mm in size and it was found to express more PTEN in the primordial follicles. As a result, compared to the other sample sizes, it also showed the least post-transplantation decline in the number of primordial follicles, indicating less follicular burn-out than the group with larger tissue surface area.