Abstract 2568: Hexane fraction of Naematoloma sublateritium extracts inhibits metastatic potential of MDA-MB-231 Breast cancer cells through modulation of the JNK and p38 pathway

Abstract

Abstract Despite years of therapeutic development and research, metastasis is still the major driver of mortality in cancer patients. Breast cancer is a second leading cause of cancer deaths in woman world-wide. The prevalence of breast cancer continues to increase by approximately 2% each year. Breast cancer also presents as metastatic disease, which has spread beyond the original organ, breast to bone, liver, lung and brain. Recently, many studies have reported that natural products- dietary phytochemicals including mushroom are known to exhibit a variety of anti-cancer, anti-invasive and anti-metastatic activities. Naematolma spp. is a basidiomycete of the fungus that is known to produce anti-tumor compound, clavaric acid. In our previous studies, HFNS has been shown to significantly inhibit cell proliferation and induce apoptosis of human estrogen-nonresponsive MDA-MB-231 breast cancer cells. In this present study, we report for the first time that hexane fraction of Naematoloma sublateritium (HFNS) regulates TNF-alpha induced invasion and migration in MDA-MB-231 cells. We observed that non-cytotoxic concentrations (10-50 μg/mL) of HFNS markedly inhibited the invasion and migration of highly metastatic MDA-MB-231 cells as shown by a Matrigel invasion assay and wound healing analysis, respectively. The results of a gelatin zymography showed that HFNS suppressed the activity of matrix metalloproteinase (MMP)-9 and urokinase plasminogen activator (uPA). Western blot results demonstrated that treatment with HFNS had decreased level of MMP-9, and uPA, while the expression of the endogenous inhibitor proteins including tissue inhibitors of MMP (TIMP-1 and TIMP-2), and plasminogen activator inhibitor (PAI)-1, was up-regulated in a dose-dependent manner. Furthermore, HFNS suppressed the phosphorylation of p38, and JNK1/2 in MDA-MB-231 cells, where extracellular signal-regulated kinase (ERK) 1/2 were not affected. It was confirmed by pretreatment with SB203580 (p38 inhibitor), SP600125 (JNK inhibitor), and PD98059 (ERK inhibitor), respectively, before stimulation with TNF-alpha. Interestingly, the HFNS treatment also led to a dose-dependent inhibition on NF-κB and activator protein-1(AP-1) binding activity which are downstream targets of JNK and p38. The gel-shift assay results supported that HFNS treatment caused down-regulation of MMP-9 and uPA gene in mRNA level. Taken together, these data suggest the inhibitory effect of HFNS on the metastatic potential of MDA-MB-231 cells through inhibiting the phosphorylation of JNK/p38 and reducing NFκB and AP-1 DNA binding activities. In conclusion, we propose that HFNS may be a safe and potential therapeutic agent against metastasis of breast cancer. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 2568. doi:1538-7445.AM2012-2568