Cold Atmospheric Plasma Attenuates Breast Cancer Cell Growth Through Regulation of Cell Microenvironment Effectors

Breast cancer exists in multiple subtypes some of which still lack a targeted and effective therapy. Cold atmospheric plasma (CAP) has been proposed as an emerging anti-cancer treatment modality. In this study, we investigated the effects of direct and indirect CAP treatment driven by the advantageous nanosecond pulsed discharge on breast cancer cells of different malignant phenotypes and estrogen receptor (ER) status, a major factor in the prognosis and therapeutic management of breast cancer. The main CAP reactive species in liquid (i.e. H2O2, NO2−/NO3−) and gas phase were determined as a function of plasma operational parameters (i.e. treatment time, pulse voltage and frequency), while pre-treatment with the ROS scavenger NAC revealed the impact of ROS in the treatment. CAP treatment induced intense phenotypic changes and apoptosis in both ER+ and ER- cells, which is associated with the mitochondrial pathway as evidenced by the increased Bax/Bcl-2 ratio and cleavage of PARP-1. Interestingly, CAP significantly reduced CD44 protein expression (a major cancer stem cell marker and matrix receptor), while differentially affected the expression of proteases and inflammatory mediators. Collectively, the findings of the present study suggest that CAP suppresses breast cancer cell growth and regulates several effectors of the tumor microenvironment and thus it could represent an efficient therapeutic approach for distinct breast cancer subtypes.

p66α Suppresses Breast Cancer Cell Growth and Migration by Acting as Co-Activator of p53

p66α is a GATA zinc finger domain-containing transcription factor that has been shown to be essential for gene silencing by participating in the NuRD complex. Several studies have suggested that p66α is a risk gene for a wide spectrum of diseases such as diabetes, schizophrenia, and breast cancer; however, its biological role has not been defined. Here, we report that p66α functions as a tumor suppressor to inhibit breast cancer cell growth and migration, evidenced by the fact that the depletion of p66α results in accelerated tumor growth and migration of breast cancer cells. Mechanistically, immunoprecipitation assays identify p66α as a p53-interacting protein that binds the DNA-binding domain of p53 molecule predominantly via its CR2 domain. Depletion of p66α in multiple breast cells results in decreased expression of p53 target genes, while over-expression of p66α results in increased expression of these target genes. Moreover, p66α promotes the transactivity of p53 by enhancing p53 binding at target promoters. Together, these findings demonstrate that p66α is a tumor suppressor by functioning as a co-activator of p53.

ARHGEF19 promotes the growth of breast cancer in vitro and in vivo by the MAPK pathway

Objective To assess the expression of ARHGEF19 in human breast cancer, investigate its role in breast cancer, and clarify the mechanism. Methods Bioinformatics analysis, immunoblot, quantitative PCR, and immunohistochemical (IHC) assays were performed to assess ARHGEF19 expression in breast cancer. CCK-8 and Edu assays were conducted to reveal its role in breast cancer cell proliferation. Flow cytometry (FCM) assays and immunoblot were performed to confirm its effects on breast cancer apoptosis. Immunoblot was also performed to clarify the mechanism. Finally, tumor growth assays were aimed to confirm the role of ARHGEF19 in mice. Results We observed that ARHGEF19 was highly expressed in human breast cancer. ARHGEF19 promoted breast cancer cell growth in vitro, and suppressed apoptosis. In addition, we found that ARHGEF19 could activate the MAPK pathway in breast cancer cells. Our findings further confirmed that ARHGEF19 contributed to breast cancer growth in mice. Conclusion We observed that ARHGEF19 promoted the growth of breast cancer in vitro and in vivo via MAPK pathway, and presume it could serve as a breast cancer therapeutic target.

Targeted Delivery of siRNA through Nanocomplex using Specific Fusion Peptides for Breast Cancer Treatment

Breast cancer is one of the serious diseases and has the second-highest mortality in women worldwide. RNA interference has been developed as a promising way of specific cancer treatment by silencing oncogenes efficiently. However, small RNAs exhibits difficulties in specific cellular uptake and instability. Therefore, we designed novel fusion peptides (RS and RT) for an efficient, stable, and specific delivery of small RNAs. Both RS and RT peptides could form self-assembled nanocomplexes via electrostatic attraction. RS nanocomplexes exhibited prolonged stability, enhanced cellular uptake, and target gene silencing by siRNAs to MDA-MB-231 breast cancer cells. Moreover, RS nanocomplexes successfully inhibited breast cancer cell growth via specific and efficient siRNA delivery. Furthermore, in vitro and in vivo safety tests showed negligible cytotoxicity and neither tissue damage nor significant inflammatory cytokine release. Therefore, the RS nanocomplexes could be expected to become a promising siRNA delivery platform for the treatment of breast cancer or other cancers.

Dual Target of EGFR and mTOR Suppress Triple Negative Breast Cancer Cell Growth Via Regulation The Phosphorylation of mTOR Downstream Proteins

Background：Triple-negative breast cancers (TNBC) are the most aggressive subtype of breast cancer, accounting for 15% - 20% of all cases, and have no response to available hormonal therapies and anti-HER2-targeted therapies due to the absence of corresponding targets. Over half of TNBC patients have overexpressed EGFR, but they are insensitive to EGFR inhibitors from monotherapy. Mammalian target of rapamycin (mTOR) connected with EGFR in the downstream signaling and involved in the progress of TNBC. The purpose of this study is to determine the combined effect of everolimus and geftinib in a TNBC cell model and investigate the possible mechanism. Results: This work showed the expression EGFR and p-mTOR protein in TNBC tissues were significantly higher than that in non-TNBC(p<0.05), while the expression of mTOR, S6K1, pEGFR and p-S6K1 were significantly higher in the EGF stimulation. EGFR and p-mTOR protein are related to poor prognosis. EGFR inhibitor gefitinib and mTOR inhibitor everolimus significantly inhibited the proliferation of human triple-negative breast cancer MDA-MB-468 cells and arrested cells in G0/G1 phase when applied separately and in combination in a dose-dependent manner (P<0.05). Meanwhile, the rate of apoptosis of MDA-MB-468 cells was significantly incresased separately by two drugs (P<0.01). Furthermore, the combination of everolimus and geftinib reduced the phosphorylation of mTOR downstream proteins. Instead, the phosphorylation of 4E-BP1 was enhanced after the everolimus and geftinib treatment, indicated an alternative activation pattern. Conclusions: These results suggested that dual inhibition of mTOR and EGFR could be a promising approach to treat TNBC.

MiR-664b-3p Inhibited Triple-Negative Breast Cancer Cell Growth Via Targeting BRIP1

BackgroundMany studies indicate that microRNAs (miRNAs) play a crucial role in modulating the development and progression of triple-negative breast cancer (TNBC). However, miR-664b-3p affections on the TNBC functions and mechanisms are still unknown. The purpose of our study was to clarify the effects of miR-664b-3p in cellular TNBC development and progression.MethodsIn our study, the expressions of miR-664b-3p in cell lines and tissueswere tested by real-time PCR (RT-PCR), immunofluorescence, H&E and immunohistochemistry staining. CCK-8 assay, colony formation, EdU, flow cytometry apoptosis, wound scratch, Transwell assays were applied to explore the cell functions. The targeted relationship between miR-664b-3p and its target BRIP1 was determined by dual-luciferase reporter assay and rescue experiments. ResultsWe observed that miR-664b-3p was significantly decreased in TNBC cell lines. Overexpression of miR-664b-3p could observably inhibit cell proliferation, migration, invasion and induced apoptosis in vitro. Meanwhile, miR-664-3p suppressed TNBC tumor growth in vivo. Furthermore, luciferase reporter assays identified the interaction between 3’UTR of BRIP1 and miR-664b-3p. Moreover, we investigated the mechanisms underlying the effect of miR-664b-3p on cell functions, and the result showed that miR-664b-3p inhibited cell proliferation, invasion and accelerated apoptosis by targeting BRIP1.ConclusionFrom the above, our findings indicated that miR-664b-3p played a significant role in TNBC progression by targeting BRIP1, providing new therapeutic targets for diagnostic in TNBC.

A novel chemical inhibitor suppresses breast cancer cell growth and metastasis through inhibiting HPIP oncoprotein

Increasing evidence suggests the pivotal role of hematopoietic pre-B-cell leukemia transcription factor (PBX)-interacting protein (HPIP/PBXIP1) in cancer development and progression, indicating that HPIP inhibition may be a promising target for cancer therapy. Here, we screened compounds inhibiting breast cancer cell proliferation with HPIP fused with green fluorescent protein as a reporter. A novel agent named TXX-1-10 derived from rimonabant, an antagonist of cannabinoid receptor 1 with anticancer effects, has been discovered to reduce HPIP expression and has greater inhibitory effects on breast cancer cell growth and metastasis in vitro and in vivo than rimonabant. TXX-1-10 regulates HPIP downstream targets, including several important kinases involved in cancer development and progression (e.g., AKT, ERK1/2, and FAK) as well as cell cycle-, apoptosis-, migration-, and epithelial-to-mesenchymal transition (EMT)-related genes. Consistent with the results of anticancer effects, genome-wide RNA sequencing indicated that TXX-1-10 has more significant effects on regulation of the expression of genes related to DNA replication, cell cycle, apoptosis, cell adhesion, cell migration, and invasion than rimonabant. In addition, TXX-1-10 significantly regulated genes associated with the cell growth and extracellular matrix organization, many of which were shown to be regulated by HPIP. Moreover, compared with rimonabant, TXX-1-10 greatly reduces blood-brain barrier penetrability to avoid adverse central depressive effects. These findings suggest that HPIP inhibition may be a useful strategy for cancer treatment and TXX-1-10 is a promising candidate drug for cancer therapy.

Targeting PI3K/AKT/mTOR Signaling Pathway in Breast Cancer

Breast cancer is the most frequently diagnosed cancer and the primary cause of cancer death in women worldwide. Although early diagnosis and cancer growth inhibition has significantly improved breast cancer survival rate over the years, there is a current need to develop more effective systemic treatments to prevent metastasis. One of the most commonly altered pathways driving breast cancer cell growth, survival, and motility is the PI3K/AKT/mTOR signaling cascade. In the past 30 years, a great surge of inhibitors targeting these key players has been developed at a rapid pace, leading to effective preclinical studies for cancer therapeutics. However, the central role of PI3K/AKT/mTOR signaling varies among diverse biological processes, suggesting the need for more specific and sophisticated strategies for their use in cancer therapy. In this review, we provide a perspective on the role of the PI3K signaling pathway and the most recently developed PI3K-targeting breast cancer therapies.