2-methoxyestradiol sensitizes tamoxifen-resistant MCF-7 breast cancer cells via downregulating HIF-1α.

The clinical studies for breast cancer (BC) are now assessing the efficacy of 2-Methoxyestradiol (2-ME), a naturally occurring derivative of estradiol. Our study aimed to explore the potential of combining the 2-ME and tamoxifen (TAM) on sensitization of TAM-resistant cells using LCC2 the TAM-resistant cells as a model and comparing the results to the sensitive cells MCF-7. Sulphorhodamine-B (SRB) assay is used to examine the 2-ME chemo-sensitizing impact on the cytotoxicity of TAM on LCC2 cells. Colorimetric assay kits were used to assess the level of the apoptosis-related markers caspases 3, Bcl2, and Bax in cell lysate. Hypoxia-inducible factor 1 alpha (HIF-1α) expression was measured using western blotting. Total cholesterol and triglyceride (TG) levels were examined colorimetrically, using the BIOLABO kit. The use of 2-ME enhanced the cytotoxic effects of TAM and effectively reversed TAM resistance. This was achieved by inhibiting the expression of HIF-1α, while concurrently increasing the levels of apoptotic marker caspase-3, as well as the pro-apoptotic protein Bax. Additionally, there was a reduction in the levels of Bcl2, an anti-apoptotic protein. Furthermore, a reduction in TG and cholesterol levels was noted. Our findings show that HIF-1α plays an important role in TAM resistance and that suppression of HIF-1α by 2-ME-mediated sensitization of BC-resistant cells to TAM. Therefore, the concurrent administration of TAM/2-ME might potentially serve as a viable therapeutic approach to address TAM resistance and enhance the overall therapy efficacy for patients with BC.

Androgen receptor blockade by flutamide down-regulates renal fibrosis, inflammation, and apoptosis pathways in male rats.

AIM: this study aims to explore the effect of androgen receptor (AR) blockade by flutamide on some renal pathologic changes such as inflammation, apoptosis, and fibrosis in male rats. MAIN METHODS: Firstly, we investigated the potential effect of AR blockade on renal inflammatory intermediates including IL-1ß, IL-6, TNF-α, NF-Òšß proteins, and the renal gene expression of NF-Қß. Besides inflammation, we also assessed the apoptosis pathways including the caspases 3 & 9, mTOR, pAKT proteins, and BAX gene expression. Besides inflammation and apoptosis pathways, we also investigated the effect of androgen blockade on renal fibrosis intermediates including vimentin, TGFß-1, α-SMA, MMP-9, collagen type-III, collagen type-IV, and the renal expression of the col1A1 gene. Besides previous pathological pathways, we assessed the expression of chloride channel protein-5 (ClC-5), as an important regulator of many renal pathological changes. Finally, we assessed the impact of previous pathological changes on renal function at biochemical and pathological levels. KEY FINDINGS: We found that AR blockade by flutamide was associated with the down-regulation of renal inflammation, apoptosis, and fibrosis markers. It was associated with expression down-regulation of IL-1ß & IL-6, TNF-α, NF-Қß, caspases 3 & 9, mTOR, MMP-9, collagens, TGFß-1, and α-SMA. Away from down-regulation, we also found that AR blockade has upregulated ClC-5 and pAKT proteins. SIGNIFICANCE: AR is a major player in androgens-induced nephrotoxicity. AR blockade downregulates renal fibrosis, inflammation, and apoptosis pathways. It may be helpful as a strategy for alleviation of renal side effects associated with some drugs. However; this needs further investigations.

miRNAs as potential game-changers in head and neck cancer: Future clinical and medicinal uses.

Head and neck cancers (HNCs) are a group of heterogeneous tumors formed most frequently from epithelial cells of the larynx, lips, oropharynx, nasopharynx, and mouth. Numerous epigenetic components, including miRNAs, have been demonstrated to have an impact on HNCs characteristics like progression, angiogenesis, initiation, and resistance to therapeutic interventions. The miRNAs may control the production of numerous genes linked to HNCs pathogenesis. The roles that miRNAs play in angiogenesis, invasion, metastasis, cell cycle, proliferation, and apoptosis are responsible for this impact. The miRNAs also have an impact on crucial HNCs-related mechanistic networks like the WNT/ß-catenin signaling, PTEN/Akt/mTOR pathway, TGFß, and KRAS mutations. miRNAs may affect how the HNCs respond to treatments like radiation and chemotherapy in addition to pathophysiology. This review aims to demonstrate the relationship between miRNAs and HNCs with a particular emphasis on how miRNAs impact HNCs signaling networks.

Hydroxycitric acid reverses tamoxifen resistance through inhibition of ATP citrate lyase.

Lipid metabolic reprogramming is involved in mediating tamoxifen (TAM) response in breast cancer cells. Published microarray data indicated that ATP citrate lyase (ACLY) is overexpressed in TAM-resistant BC cells. Hydroxycitric acid (HCA) is a powerful competitive inhibitor of the enzyme ACLY, which links carbohydrates and lipids metabolism. However, whether inhibition of ACLY could modulate TAM response in TAM-resistant BC cells remained unexplored. Thus the current study aimed to explore the effect of ACLY inhibition on TAM-resistant BC cells. The cytotoxicity of TAM and/or HCA on LCC2 and its TAM-sensitive counterpart MCF7 cells was evaluated. Also, the effect of TAM and/or HCA treatments on ACLY protein levels were investigated by western blotting. In addition, the effects of TAM and/or HCA on caspase-3, Bax, and Bcl2 levels were evaluated by ELISA.; besides, and flow cytometric analysis was performed for the detection of apoptosis. Moreover, cholesterol and triglyceride contents of LCC2 and MCF7 were quantified colorimetrically. Our results demonstrated that TAM/HCA co-treatment synergistically diminished LCC2 and MCF7 cell viability, with the effect being more significant on LCC2. Mechanistically, TAM/HCA co-treatment decreases the expression level of ACLY in LCC2 by 74 %, while in MCF7 by only 59 %. Moreover, apoptosis marker caspase-3 and Bax were increased, while the anti-apoptotic Bcl2 was decreased. Furthermore, the cholesterol and TG contents were increased in LCC2 than in MCF7. Our data revealed that ACLY plays a key role in TAM resistance and ACLY inhibition by HCA-mediated sensitization of BC-resistant cells to TAM.

miRNA-193b-5p Suppresses Pancreatic Cancer Cell Proliferation, Invasion, Epithelial Mesenchymal Transition, and Tumor Growth by Inhibiting eEF2K.

BACKGROUND: Pancreatic ductal adenocarcinoma (PDAC) is the 4th leading cause of cancer deaths in the US due to the lack of effective targeted therapeutics and extremely poor prognosis. OBJECTIVE: The study aims to investigate the role of miR-193b and related signaling mechanisms in PDAC cell proliferation, invasion, and tumor growth. METHODS: Using PDAC cell lines, we performed cell viability, colony formation, in vitro wound healing, and matrigel invasion assays following transfection with miR-193b mimic or control-miR. To identify potential downstream targets of miR-193b, we utilized miRNA-target prediction algorithms and investigated the regulation of eukaryotic elongation factor-2 kinase (eEF2K) and mitogen-activated protein kinase/extracellular signal-regulated kinase (MAPK/ERK) signaling pathways and mediators of epithelial mesenchymal transition (EMT). The role of miR-193b in PDAC tumorigenesis was evaluated in in vivo tumor growth of Panc-1 xenograft model in nude mice. RESULTS: We found that miR-193b is under expressed in PDAC cells compared to corresponding normal pancreatic epithelial cells and demonstrated that ectopic expression of miR-193b reduced cell proliferation, migration, invasion, and EMT through downregulation of eEF2K signaling in PDAC cells. miR-193b expression led to increased expression of E-Cadherin and Claudin-1 while decreasing Snail and TCF8/ZEB1 expressions via eEF2K and MAPK/ERK axis. In vivo systemic injection of miR-193b using lipid-nanoparticles twice a week reduced tumor growth of Panc-1 xenografts and eEF2K expression in nude mice. CONCLUSIONS: Our findings suggest that miR-193b expression suppresses PDAC cell proliferation, migration, invasion, and EMT through inhibition of eEF2K/MAPK-ERK oncogenic axis and that miR-193b-based RNA therapy might be an effective therapeutic strategy to control the growth of PDAC.

ncRNA therapy with miRNA-22-3p suppresses the growth of triple-negative breast cancer.

Deregulation of noncoding RNAs, including microRNAs (miRs), is implicated in the pathogenesis of many human cancers, including breast cancer. Through extensive analysis of The Cancer Genome Atlas, we found that expression of miR-22-3p is markedly lower in triple-negative breast cancer (TNBC) than in normal breast tissue. The restoration of miR-22-3p expression led to significant inhibition of TNBC cell proliferation, colony formation, migration, and invasion. We demonstrated that miR-22-3p reduces eukaryotic elongation factor 2 kinase (eEF2K) expression by directly binding to the 3' untranslated region of eEF2K mRNA. Inhibition of EF2K expression recapitulated the effects of miR-22-3p on TNBC cell proliferation, motility, invasion, and suppression of phosphatidylinositol 3-kinase/Akt and Src signaling. Systemic administration of miR-22-3p in single-lipid nanoparticles significantly suppressed tumor growth in orthotopic MDA-MB-231 and MDA-MB-436 TNBC models. Evaluation of the tumor response, following miR-22-3p therapy in these models using a novel mathematical model factoring in various in vivo parameters, demonstrated that the therapy is highly effective against TNBC. These findings suggest that miR-22-3p functions as a tumor suppressor by targeting clinically significant oncogenic pathways and that miR-22-3p loss contributes to TNBC growth and progression. The restoration of miR-22-3p expression is a potential novel noncoding RNA-based therapy for TNBC.