Jeong JY, et al. Endocrinol Metab. 2013 Dec;28(4):288-296. https://doi.org/10.3803/EnM.2013.28.4.288

Chitinase 3‐like 1 (CHI3L1) is a secreted glycoprotein that has pleiotropic activity in aggressive cancers. In our study, we examined the expression and function of CHI3L1 in glioma cells. CHI3L1 was highly expressed in human glioma tissue, whereas its expression in normal brain tissue was very low. CHI3L1 suppression by shRNA reduced glioma cell invasion, anchorage‐independent growth and increased cell death triggered by several anticancer drugs, including cisplatin, etoposide and doxorubicin, whereas CHI3L1 overexpression had the opposite effect in glioma cells. Because the invasive nature of glioma cells plays a critical role in the high morbidity of glioma, we have further defined the role of CHI3L1 in the process of glioma invasion. Downregulation of CHI3L1 results in decreased cell–matrix adhesion and causes a marked increase in stress fiber formation and cell size with fewer cellular processes. Furthermore, the expression and activity of matrix metalloproteinase‐2 was also decreased in glioma cells in which CHI3L1 was knocked down. Taken together, these results suggest that CHI3L1 plays an important role in the regulation of malignant transformation and local invasiveness in gliomas. Thus, targeting the CHI3L1 molecule may be a potential therapeutic molecular target for gliomas.

Calcium (Ca²⁺) signaling is an important signaling process, implicated in cancer cell proliferation and motility of the deadly glioblastomas that aggressively invade neighboring brain tissue. We have previously demonstrated that caffeine blocks glioblastoma invasion and extends survival by inhibiting Ca²⁺ release channel inositol 1,4,5-trisphosphate receptor (IP₃R) subtype 3. Trifluoperazine (TFP) is an FDA-approved antipsychotic drug for schizophrenia. Interestingly, TFP has been recently reported to show a strong anticancer effect on lung cancer, hepatocellular carcinoma, and T-cell lymphoma. However, the possible anticancer effect of TFP on glioblastoma has not been tested. Here, we report that TFP potently suppresses proliferation, motility, and invasion of glioblastoma cells in vitro, and tumor growth in in vivo xenograft mouse model. Unlike caffeine, TFP triggers massive and irreversible release of Ca²⁺ from intracellular stores by IP₃R subtype 1 and 2 by directly interacting at the TFP-binding site of a Ca²⁺-binding protein, calmodulin subtype 2 (CaM2). TFP binding to CaM2 causes a dissociation of CaM2 from IP₃R and subsequent opening of IP₃R. Compared with the control neural stem cells, various glioblastoma cell lines showed enhanced expression of CaM2 and thus enhanced sensitivity to TFP. On the basis of these findings, we propose TFP as a potential therapeutic drug for glioblastoma by aberrantly and irreversibly increasing Ca²⁺ in glioblastoma cells. Mol Cancer Ther; 16(1); 217–27. ©2016 AACR.

Caffeine is the most commonly ingested methylxanthine and has anti-cancer effects in several types of cancer. In this study, we examined the anti-cancer effects of caffeine on gliomas, both in vitro and in vivo. In vitro, caffeine treatment reduced glioma cell proliferation through G₀/G₁-phase cell cycle arrest by suppressing Rb phosphorylation. In addition, caffeine induced apoptosis through caspase-3 activation and poly(ADP-ribose) polymerase (PARP) cleavage. Caffeine also phosphorylated serine 9 of glycogen synthase kinase 3 beta (GSK3β). Pretreatment with H89, a pharmacological inhibitor of protein kinase A (PKA), was able to antagonize caffeine-induced GSK3β^ser9 phosphorylation, suggesting that the mechanism might involve a cAMP-dependent PKA-dependent pathway. In vivo, caffeine-treated tumors exhibited reduced proliferation and increased apoptosis compared with vehicle-treated tumors. These results suggest that caffeine induces cell cycle arrest and caspase-dependent cell death in glioma cells, supporting its potential use in chemotherapeutic options for malignant gliomas.

Purpose: Ischemia/reperfusion (I/R) injury induces apoptosis in retinal ganglion cells (RGCs). Resveratrol (Res) is a potent natural antioxidant with beneficial effects in many ocular diseases, such as age-related macular degeneration, diabetic retinopathy, and glaucoma. Because caspase-3 expression is highly correlated with activation of the apoptotic pathway, the present study aimed to determine whether Res regulates the expression of caspase-3 using an I/R retinal injury mouse model. Methods: Male C57BL/6J mice were injected with Res for 2 consecutive days before I/R retinal injury. I/R retinal injury was induced by increasing the intraocular pressure for 1 h. Res was then injected for 3 consecutive days. Changes in retinal morphology were monitored for 3 days after injury by histochemistry using hematoxylin and eosin staining. mRNAs and proteins were extracted 2 days after injury. The expression levels of caspase-8 and caspase-3 mRNA and protein were determined using reverse-transcriptase polymerase chain reaction (RT-PCR) and western blot analyses. Results: I/R injury induced declines in retinal thickness and number of RGCs during 5 days after injury. Caspase-8 and caspase-3 mRNA and protein activation increased. Res treatment reduced the significant loss of retinal morphology and downregulated the expression of mRNA and activation of caspase-8 and caspase-3 protein. Conclusions: The observed changes in retinal morphology suggest that I/R injury promotes retinal degeneration. Increased expression of caspase-8 and caspase-3 mRNA indicates apoptosis activation. Res, however, suppresses apoptosis via downregulation of caspase-8 and caspase-3 expression.

Rho GDP dissociation inhibitor 2 (RhoGDI2) expression is correlated with tumor growth, metastasis and chemoresistance in gastric cancer. However, the mechanisms by which RhoGDI2 promotes tumor cell survival and metastasis remain unclear. In this study, we clearly demonstrate that RhoGDI2 upregulates VEGF‐C expression and RhoGDI2 expression is positively correlated with VEGF‐C expression in human gastric tumor tissues as well as parental gastric cancer cell lines. VEGF‐C depletion suppressed RhoGDI2‐induced gastric cancer metastasis and sensitized RhoGDI2‐overexpressing cells to cisplatin‐induced apoptosis in vitro and in vivo. Secreted VEGF‐C enhanced gastric cancer cell invasion and conferred cisplatin resistance to RhoGDI2‐overexpressing cells. We also show that RhoGDI2 positively regulates Rac1 activity in gastric cancer cells. Inhibition of Rac1 expression suppressed RhoGDI2‐induced VEGF‐C expression, and this inhibition was associated with decreased invasiveness and increased sensitivity to cisplatin in RhoGDI2‐overexpressing cells. Our results indicate that RhoGDI2 might be a potential therapeutic target for simultaneously reducing metastasis risk and enhancing chemotherapy efficacy in gastric cancer.