The Interaction of PI3K Inhibition with Homologous Recombination Repair in Triple Negative Breast Cancer Cells

Purpose: Aberrant activation of the phosphatidylinositol 3'-kinase (PI3K)-Akt signaling pathway is observed in many types of human cancer including triple negative breast cancer (TNBC). Additionally, dysregulation in the homologous recombination (HR)-dependent DNA-repair is associated with TNBC phenotype due to BRCA1/2 mutations or HR deficiency. Therefore, the hypothesis of this study was to evaluate the association of PI3K inhibition with HR pathway in TNBC in terms of BRCA1 mutation status. Methods: To examine the potential therapeutic effect of LY294002, an inhibitor of PI3K, on TNBC cell lines with known BRCA1 status, WST-1, annexin V, cell cycle analysis and AO/EB staining were performed. Additionally, RT-PCR and immunofluorescence analysis was used to explore the interaction between the inhibition of PI3K and HR functionality. Results: The findings showed that LY294002 could significantly inhibited the proliferation of TNBC cells. Furthermore, the suppression of PI3K resulted in HR impairment by BRCA1 and RAD51 downregulation and apoptotic cell death by the induction of DNA damage and BAX overexpression. Therefore, LY294002 was more effective in BRCA1-deficient TNBC cells. Conclusions: Consequently, targeted therapies based on the interaction of PI3K inhibition with BRCA1 mutations or HR deficiency in TNBC may be a promising strategy for the treatment of patients with TNBC

Inhibition of TLR4/TRIF/IRF3 Signaling Pathway by Curcumin in Breast Cancer Cells

Purpose: Toll-like receptor 4 (TLR4) is over-expressed in breast tumors and thus contributing to the tumor progression and metastasis. Natural products have drawn attention in cancer immunotherapy due to their various biological activities. Curcumin is well investigated in different types of cancer. However, the mechanisms underlying its anti-inflammatory actions have not been extensively elucidated. For this purpose, we explored the inhibitory effects of curcumin on lipopolysaccharide (LPS)-induced TLR4 dependent TRIF signaling pathway in two subtypes of breast cancer cell lines (MCF-7 and MDA-MB-231) in this study. Methods: In this context, the cytotoxicity of curcumin and LPS alone and the combination of curcumin with LPS on these cells was evaluated by WST-1 assay. The expression level of TLR4 and the release of type I interferon (IFN) levels were determined after treatment with curcumin and/or LPS by RT-PCR and ELISA analysis, respectively. Furthermore, the subcellular localization of TLR4 and interferon regulatory factor 3 (IRF3) were detected by immunofluorescence analysis. Results: Curcumin treatment suppressed breast cancer cells viabilities and the activation of TLR4-mediated TRIF signaling pathway by the downregulation of TLR4 and IRF3 expression levels and the inhibition of type I IFN (IFN-alpha/beta) levels induced by LPS. However, curcumin was more efficient in MDA-MB-231 cells than MCF-7 cells owing to its greater inhibitory efficacy in the LPS-enhanced TLR4 signaling pathway. Furthermore, IFN-alpha/beta levels induced by TLR4 and IRF3 were decreased in these cells following curcumin treatment. Conclusions: Consequently, these results demonstrated that the activation of LPS stimulated TLR4/TRIF/IRF3 signaling pathway was mediated by curcumin in breast cancer cells, in vitro. However, more studies are necessary to examine the curcumin's anti-inflammatory activities on TLR4/MyD88/NF-kappa B as well as other signaling pathways downstream of TLRs in breast cancer

IL-6 mediated JAK/STAT3 signaling pathway in cancer patients with cachexia

CONCLUSION: STAT3 may be considered as a therapeutic target for cachectic patients with gastric, lung and breast cancer. Furthermore, IL-6 mediates STAT3 activation in cachectic gastric and breast cancer patients (Tab. 5, Fig. 2, Ref. 62)

The Impact of Caffeic Acid Loaded Solid Lipid Nanoparticles on Cancer Treatment

In an attempt to develop caffeic acid for drug delivery, caffeic acid-loaded solid lipid nanoparticles (CA-SLNs) were constructed, and were characterized to determine their properties followed by their evaluation for in vitro cytotoxic properties. The SLNs were prepared by using hot homogenization method. The treatment of H-Ras 5RP7 and NIH/3T3 cell lines with CA and CA-SLNs suggested that CA-SLNs are less toxic to NIH/3T3 normal cells but have more cytotoxic effects on H-Ras 5RP7 as compared with free CA by using MTT assay. In addition, CA-SLNs can increase the cytotoxic effect and accelerate cellular uptake of CA on H-Ras 5RP7 cells. Finally, we observed the structural and ultrastructural changes in both H-Ras 5RP7 and NIH/3T3 cells by using transmission electron and confocal microscopy, respectively. We observed both structure and ultrastructural changes in H-Ras 5RP7 cells without causing any damage to NIH/3T3 cells. These results showed that the SLNs formulation may be promising as a substitute nanosize based drug delivery system for cancer treatment

In vitro cytotoxic and antiproliferative effects of usnic acid on hormone-dependent breast and prostate cancer cells

The aim of the current study was first to investigate cytotoxic activity of usnic acid (UA) on hormone-dependent breast and prostate cancer, and normal cells. Cells were treated with increasing concentrations (25 to 150 mu M) of UA for 48hours and cell viability, quantitative and morphological analysis of cell death, and cell cycle analysis were performed. UA was shown to have selective cytotoxicity on hormone-dependent cancer cells with the IC50 levels of 71.4 and 77.5 mu M for MCF7 and LNCaP cells, respectively. UA induced apoptotic cell death and G0/G1 cell cycle arrest without damaging normal cells. MCF7 cells were more sensitive to UA than LNCaP cells. Our results first revealed that UA is a promising candidate as an alternative agent for hormone-dependent breast and prostate cancers. However, molecular mechanism underlying the UA-mediated cell death in cancer cells should be investigated further

Solid lipid nanoparticles: Reversal of tamoxifen resistance in breast cancer

The objective of the present study was to investigate the effect of tamoxifen (Tam) loaded solid lipid nano-particles (SLNs) on MCF7 Tam-resistant breast cancer cells (MCF7-TamR). Tam-SLNs were produced by the hot homogenization method. The characterization studies of Tam-SLNs demonstrated good physical stability with small particle size. The in vitro cytotoxicity results showed that Tam-SLNs enhanced the efficacy of Tam and reversed the acquired Tam resistance by inducing apoptosis, altering the expression levels of specific miRNA and the related apoptosis-associated target-genes in both MCF7 and MCF7-TamR cells without damaging the MCF10A control cells (p < 0.05). In conclusion, we demonstrated a molecular mechanism of the induction of apoptosis by Tam-SLNs in MCF7 and MCF7-TamR cells, and thus, we demonstrated that Tam-SLNs were more effective than Tam. The present study suggests that the use SLNs may be a potential therapeutic strategy to overcome Tam-resistance in breast cancer for clinical use