Department of Pharmaceutical Sciences, Institute of Biomarker and Molecular Therapeutics (IBMT), College of Pharmacy, University of Tennessee Health Science Center, 881 Madison Avenue, Memphis, TN, 38163, USA.
J Exp Clin Cancer Res. 2019 Jan 23;38(1):29. doi: 10.1186/s13046-018-1009-7.
The management of pancreatic cancer (PanCa) is exceptionally difficult due to poor response to available therapeutic modalities. Tubulins play a major role in cell dynamics, thus are important molecular targets for cancer therapy. Among various tubulins, βIII and βIV-tubulin isoforms have been primarily implicated in PanCa progression, metastasis and chemo-resistance. However, specific inhibitors of these isoforms that have potent anti-cancer activity with low toxicity are not readily available.
We determined anti-cancer molecular mechanisms and therapeutic efficacy of a novel small molecule inhibitor (VERU-111) using in vitro (MTS, wound healing, Boyden chamber and real-time xCELLigence assays) and in vivo (xenograft studies) models of PanCa. The effects of VERU-111 treatment on the expression of β-tubulin isoforms, apoptosis, cancer markers and microRNAs were determined by Western blot, immunohistochemistry (IHC), confocal microscopy, qRT-PCR and in situ hybridization (ISH) analyses.
We have identified a novel small molecule inhibitor (VERU-111), which preferentially represses clinically important, βIII and βIV tubulin isoforms via restoring the expression of miR-200c. As a result, VERU-111 efficiently inhibited tumorigenic and metastatic characteristics of PanCa cells. VERU-111 arrested the cell cycle in the G2/M phase and induced apoptosis in PanCa cell lines via modulation of cell cycle regulatory (Cdc2, Cdc25c, and Cyclin B1) and apoptosis - associated (Bax, Bad, Bcl-2, and Bcl-xl) proteins. VERU-111 treatment also inhibited tumor growth (P < 0.01) in a PanCa xenograft mouse model.
This study has identified an inhibitor of βIII/βIV tubulins, which appears to have excellent potential as monotherapy or in combination with conventional therapeutic regimens for PanCa treatment.
由于对现有治疗方式的反应不佳，胰腺癌（PanCa）的治疗极具挑战性。微管蛋白在细胞动力学中发挥着重要作用，因此是癌症治疗的重要分子靶点。在各种微管蛋白中，βIII 和 βIV 微管蛋白同工型主要与 PanCa 的进展、转移和化疗耐药有关。然而，针对这些同工型的特异性抑制剂，具有强大的抗癌活性且毒性低的抑制剂并不易得。
我们使用体外（MTS、划痕愈合、Boyden 室和实时 xCELLigence 测定）和体内（异种移植研究）PanCa 模型来确定新型小分子抑制剂（VERU-111）的抗癌分子机制和治疗效果。通过 Western blot、免疫组化（IHC）、共聚焦显微镜、qRT-PCR 和原位杂交（ISH）分析，确定 VERU-111 处理对β-微管蛋白同工型表达、细胞凋亡、癌症标志物和 microRNAs 的影响。
我们发现了一种新型小分子抑制剂（VERU-111），它通过恢复 miR-200c 的表达，优先抑制临床上重要的βIII 和βIV 微管蛋白同工型。因此，VERU-111 有效地抑制了 PanCa 细胞的致瘤和转移特性。VERU-111 通过调节细胞周期调节蛋白（Cdc2、Cdc25c 和 Cyclin B1）和凋亡相关蛋白（Bax、Bad、Bcl-2 和 Bcl-xl）使 PanCa 细胞系的细胞周期停滞在 G2/M 期并诱导细胞凋亡。VERU-111 还抑制了 PanCa 异种移植小鼠模型中的肿瘤生长（P<0.01）。
本研究鉴定了一种βIII/βIV 微管蛋白抑制剂，它似乎具有作为单一疗法或与传统治疗方案联合治疗 PanCa 的巨大潜力。
