Aurora kinase A (Aurora-A), a serine/threonine kinase, plays a pivotal role in various cellular processes, including mitotic entry, centrosome maturation and spindle formation. Overexpression or gene-amplification/mutation of Aurora-A kinase occurs in different types of cancer, including lung cancer, colorectal cancer, and breast cancer. Alteration of Aurora-A impacts multiple cancer hallmarks, especially, immortalization, energy metabolism, immune escape and cell death resistance which are involved in cancer progression and resistance. This review highlights the most recent advances in the oncogenic roles and related multiple cancer hallmarks of Aurora-A kinase-driving cancer therapy resistance, including chemoresistance (taxanes, cisplatin, cyclophosphamide), targeted therapy resistance (osimertinib, imatinib, sorafenib, etc.), endocrine therapy resistance (tamoxifen, fulvestrant) and radioresistance. Specifically, the mechanisms of Aurora-A kinase promote acquired resistance through modulating DNA damage repair, feedback activation bypass pathways, resistance to apoptosis, necroptosis and autophagy, metastasis, and stemness. Noticeably, our review also summarizes the promising synthetic lethality strategy for Aurora-A inhibitors in RB1, ARID1A and MYC gene mutation tumors, and potential synergistic strategy for mTOR, PAK1, MDM2, MEK inhibitors or PD-L1 antibodies combined with targeting Aurora-A kinase. In addition, we discuss the design and development of the novel class of Aurora-A inhibitors in precision medicine for cancer treatment.

LncRNA ZFAS1 (ZNFX1 antisense RNA1) plays key roles in the occurrence and progression of various cancers, including colorectal cancer, glioma, lung cancer, gastric cancer, and so on. To date, relatively little is known about its potential role in development and/or progression of clear cell renal cell carcinoma (ccRCC). Expression level of ZFAS1 and miR-10a in 60 ccRCC and 20 adjacent non-tumor tissues were determined by using qRT-PCR. The effect of knockdown of ZFAS1 on cell proliferation, migration and invasion were measured by CCK-8 assay, transwell migration and invasion assay, respectively. The correlation of ZFAS1 and miR-10a was analyzed by bioinformatics DIANA TOOLS. Protein and mRNA expression of spindle and kinetochore-associated protein 1(SKA1) were determined by western blot and qRT-PCR analysis, respectively. Interactions between ZFAS1 and miR-10a were verified by luciferase reporter assay and RNA immunoprecipitation (RIP) assay, and interactions between miR-10a and SKA1 was verified by a luciferase reporter assay. We observed that high-level expression of ZFAS1 is positively correlated with poor prognosis and shorter overall survival (OS) in patients with ccRCC. Knockdown of ZFAS1 significantly suppressed proliferation, migration and invasion of ccRCC cells. Furthermore, miR-10a was identified as a target of ZFAS1. Silencing miR-10a could attenuate the ability of ZFAS1 in promoting proliferation and metastasis of ccRCC. Subsequently, our studies validated that SKA1, as a key downstream target protein for miR-10a, is responsible for the biological role of ZFAS1. ZFAS1 positively regulated SKA1 expression via sponging miR-10a. Taken together, our findings suggest that ZFAS1 promotes growth and metastasis of ccRCC via targeting miR-10a/SKA1 pathway, which may represent a novel therapeutic target or biomarker for ccRCC.

This study investigated the in vitro and in vivo antiproliferative activity of esculetin against hepatocellular carcinoma, and clarified its potential molecular mechanisms. Cell viability was determined by the MTT (tetrazolium) colorimetric assay. In vivo antitumor activity of esculetin was evaluated in a hepatocellular carcinoma mouse model. Seventy-five C57BL/6J mice were implanted with Hepa1-6 cells and randomized into five groups (n=15 each) given daily intraperitoneal injections of vehicle (physiological saline), esculetin (200, 400, or 700 mg·kg^-1·day^-1), or 5-Fu (200 mg·kg^-1·day^-1) for 15 days. Esculetin significantly decreased tumor growth in mice bearing Hepa1-6 cells. Tumor weight was decreased by 20.33, 40.37, and 55.42% with increasing doses of esculetin. Esculetin significantly inhibited proliferation of HCC cells in a concentration- and time-dependent manner and with an IC₅₀ value of 2.24 mM. It blocked the cell cycle at S phase and induced apoptosis in SMMC-7721 cells with significant elevation of caspase-3 and caspase-9 activity, but did not affect caspase-8 activity. Moreover, esculetin treatment resulted in the collapse of mitochondrial membrane potential in vitro and in vivo accompanied by increased Bax expression and decreased Bcl-2 expression at both transcriptional and translational levels. Thus, esculetin exerted in vitro and in vivo antiproliferative activity in hepatocellular carcinoma, and its mechanisms involved initiation of a mitochondrial-mediated, caspase-dependent apoptosis pathway.

Protein kinase D (PKD) signaling plays a critical role in the regulation of DNA synthesis, proliferation, cell survival, adhesion, invasion/migration, motility, and angiogenesis. To date, relatively little is known about the potential role of PKD in the development and/or progression of human colorectal cancer. We evaluated the expression of different PKD isoforms in colorectal cancer and investigated the antitumor activity of PKD inhibitors against human colorectal cancer. PKD2 was the dominant isoform expressed in human colon cancer cells. PKD3 expression was also observed but PKD1 expression, at both the RNA and protein levels, was not detected. Suppression of PKD using the small molecule inhibitors CRT0066101 and kb-NB142-70 resulted in low micromolar in vitro antiproliferative activity against multiple human colorectal cancer cell lines. Drug treatment was associated with dose-dependent suppression of PKD2 activation. Incubation with CRT0066101 resulted in G₂–M phase arrest and induction of apoptosis in human colorectal cancer cells. Further studies showed that CRT0066101 treatment gave rise to a dose-dependent increase in expression of cleaved PARP and activated caspase-3, in addition to inhibition of AKT and ERK signaling, and suppression of NF-κB activity. Transfection of PKD2-targeted siRNAs resulted in similar effects on downstream pathways as observed with small molecule inhibitors. Daily administration of CRT0066101 resulted in significant inhibition of tumor growth in HCT116 xenograft nude mice. Taken together, our studies show that PKD plays a significant role in mediating growth signaling in colorectal cancer and may represent a novel chemotherapeutic target for the treatment of colorectal cancer. Mol Cancer Ther; 13(5); 1130–41. ©2014 AACR.