The total results showed, in malignant glioma cell lines however, not in HEB cells, PEITC significantly upregulated miR-135a, which was however completely reversed by 7.5 mM GSH, a ROS scavenger (Determine 5C). Bax expression and Cytochrome-C release in malignant glioma cell lines but not in the immortalized human normal glial HEB cells. Correspondingly, the above PEITC-induced activation of the ROS-MiR-135a-Mitochondria dependent apoptosis pathways in malignant glioma was attenuated by pre-transfection with miR-135a inhibitor, pre-treatment with multidrug resistance-associated protein 1 (MRP1) inhibitor Sch B, or combination with glutathione (GSH). These results revealed that PEITC selectively induced apoptosis of malignant glioma cells through MRP1-mediated export of GSH to activate ROS-MiR-135a-Mitochondria dependent apoptosis pathway, suggesting a potential application of PEITC for treating glioma. strong class=”kwd-title” Keywords: Phenethyl isothiocyanate, miR-135a, MRP1, selective lethality, glioma Introduction Glioblastoma multiforme (GBM) is the most common primary central nervous system (CNS) tumor (account for approximately 80%) [1,2]. Despite recent advances in the diagnosis, surgery, chemotherapy and radiation therapy, the prognosis for GBM remains very poor with the median survival time of only 12-15 months [3]. In clinical, temozolomide (TMZ) is the first line chemotherapy drug for GBM [4]. Eprosartan However, due to blood brain barrier (BBB), low O6-methylguanine-DNA methyltransferase Eprosartan (MGMT) promoter methylation rate [5] and multiple drug resistance of glioblastoma, the efficacy of TMZ-based radiochemotherapy is usually low. Thus, it is urgent to develop novel and effective treatment modalities including new chemotherapy drugs for the management of glioblastoma. Phenethyl isothiocyanate (PEITC) is usually released from glucosinolates by cutting or chewing activated enzyme myrosinase [6] and known to be one of the major bioactive compounds present in cruciferous vegetables such as watercress, broccoli and Brussels sprouts [7]. Previous studies have revealed PEITC has broad spectrum and remarkable anti-cancer effects by inducing apoptosis [8-11] and reversing chemotherapy-drug resistance [8,12-15]. PEITC has been shown to selectively kill malignant cancer cells but not the corresponding normal cells [13,15-17] through potent induction of reactive oxygen species (ROS) in malignant cancer cells but not in normal cells [18]. However, this ROS-based cancer therapy has been recently questioned [19]. Thus, the mechanisms of the selective XRCC9 lethality of PEITC to cancer cells remain to be determined in suitable models. MicroRNAs (miRNAs) are endogenous small non-coding RNAs that act as crucial gene regulators at post-transcriptional level, and play an important role in the initiation, progression and prognostic of Eprosartan various human cancers [20]. Emerging evidences have revealed miRNAs play pivotal roles in the response and resistance of anti-cancer brokers [21,22]. Moreover, various studies have revealed anti-cancer agents trigger cancer cells apoptosis through inducing ROS, which in turn regulate a wide range of miRNAs [23-25], revealing new roles of miRNA in cancer therapy responses. MiR-135a is one of the ROS-regulated miRNAs [26] and has been demonstrated to function as a selective killer of malignant glioma through mitochondria-dependent pathways [27]. A previous study showed that PEITC, a strong ROS inducer and selective killer of malignant cancer cells, could induce apoptosis of glioma cells through the extrinsic- and intrinsic-apoptosis signaling pathways [28]. Thus, we hypothesize whether PEITC may function as a selective killer to malignant glioma cells through ROS production to activate miR-135a-mitochondria dependent apoptosis pathway. Moreover, various studies have exhibited that multidrug resistance-associated protein 1(MRP1) is usually overexpressed in glioblastoma and plays a pivotal role in PEITC-induced ROS production through depleting GSH in cancer cells. Thus, it is also possible that MRP1 is usually involved in the selective lethality of PEITC to malignant glioma cells via ROS-MiR-135a-Mitochondria dependent apoptosis pathways. In the current study, using immortalized human normal glial cell line (HEB) and malignant glioma cell lines (U87, U251, T98G) as models, we explored the potential mechanisms of PEITC as a selective killer to malignant glioma cells. Our results exhibited that PEITC induced selective lethality and suppressed tumorigenicity and migration of malignant glioma cells through MRP1-mediated ROS production thereby activating miR-135a-mitochondria dependent apoptosis pathways, suggesting PEITC is usually a potential efficient agent for the treatment of glioma. Materials and methods Cell culture Human normal glial cell line (HEB) and malignant glioma U87, U251 and T98G cell lines were kindly provided by Dr. Wu (Department of Pharmacology, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou, China). Malignant glioma U343 and HS683 cell lines were.
