HuR-targeted small molecule inhibitor exhibits cytotoxicity towards human lung cancer cells

Abstract

Human antigen (Hu) R is an RNA-binding protein whose overexpression in human cancer correlates with aggressive disease, drug resistance, and poor prognosis. HuR inhibition has profound anticancer activity. Pharmacologic inhibitors can overcome the limitations of genetic inhibition. In this study, we examined the antitumor activity of CMLD-2, a small-molecule inhibitor directed against HuR, using non-small cell lung cancer (NSCLC) as a model. CMLD-2 efficacy was tested in vitro using H1299, A549, HCC827, and H1975 NSCLC cells and MRC-9 and CCD-16 normal human fibroblasts. Treatment of NSCLC cells with CMLD-2 produced dose-dependent cytotoxicity, caused a G1 phase cell-cycle arrest and induced apoptosis. CMLD-2 decreased HuR mRNA and the mRNAs of HuR-regulated proteins (Bcl2 and p27) in tumor cells. Additionally, reduction in the expression of HuR, Bcl2, cyclin E, and Bcl-XL with increased expression of Bax and p27 in CMLD-2-treated NSCLC cells were observed. CMLD-2-treated normal cells, HuR-regulated mRNAs and proteins albeit showed some reduction were less compared to tumor cells. Finally, CMLD-2 treatment resulted in greater mitochondrial perturbation, activation of caspase-9 and -3 and cleavage of PARP in tumor cells compared to normal cells. Our proof-of concept study results demonstrate CMLD-2 represents a promising HuR-targeted therapeutic class that with further development could lead to advanced preclinical studied and ultimately for lung cancer treatment.

MiR-19b non-canonical binding is directed by HuR and confers chemosensitivity through regulation of P-glycoprotein in breast cancer

“…In contrast, our data support a tumour suppressor role for miR-19b in breast epithelial cells, in accordance with some data in prostate cancer (Ottman et al, 2016) and hepatocellular carcinoma (Hung et al, 2015). HuR has also been defined as an oncogene, with higher expression associated with poor survival in breast and other cancers (Zhu et al, 2013, Denkert et al, 2004, and it is the focus of ongoing work to develop novel targeted therapeutics (Huang et al, 2016, Muralidharan et al, 2017, Wu et al, 2015. Strangely, expression levels of HuR and P-gp have previously been shown to correlate positively in breast cancer (Zhu et al, 2013), in direct contrast to the regulation we have identified, although this previous observation may be compromised by the lack of antibody validation.…”

HuR Reduces Radiation-Induced DNA Damage by Enhancing Expression of ARID1A

“…Actinomycin D (Sigma) was dissolved in Dimethyl sulfoxide (DMSO) and used at the final concentration of 5 µg/mL. The HuR inhibitor, CMLD-2, was synthesized and used as previously described [43,54]. The compound was dissolved in DMSO and used in the studies described herein.…”

The mRNA‐Binding Protein HuR Is a Kinetically‐Privileged Electrophile Sensor

“…Unsurprisingly, knockdown of HuR is an established means to reduce anchorage‐independent growth and oncogenic potential of at least some sets of cancer cells . The disease relevance of HuR has propelled efforts to identify small‐molecule inhibitors of HuR, which have yielded some initial hits that show potential promise as useful therapeutics . These molecules mostly appear to interfere with HuR dimerization, which is essential for HuR function .…”