Isoliquiritigenin attenuates diabetic cardiomyopathy via inhibition of hyperglycemia-induced inflammatory response and oxidative stress.

BACKGROUND: Inflammation and oxidative stress play essential roles in the occurrence and progression of diabetic cardiomyopathy (DCM). Isoliquiritigenin (ISL), a natural chalcone, exhibits strong anti-inflammatory and antioxidant activities. HYPOTHESIS/PURPOSE: In this study, we aimed to investigate the protective effects of ISL on DCM using high glucose (HG)-challenged cultured cardiomyocytes and streptozotocin (STZ)-induced diabetic mice. STUDY DESIGN AND METHODS: Embryonic rat heart-derived H9c2 cells challenged with a high concentration of glucose were used to evaluate the anti-inflammatory and antioxidant effects of ISL. STZ-induced diabetic mice were used to study the effects of ISL in DCM in vivo. Furthermore, cardiac fibrosis, hypertrophy, and apoptosis were explored both in vitro and in vivo. RESULTS: ISL effectively inhibited HG-induced hypertrophy, fibrosis, and apoptosis probably by alleviating the inflammatory response and oxidative stress in H9c2 cells. Results from in vivo experiments showed that ISL exhibited anti-inflammatory and antioxidant stress activities that were characterized by the attenuation of cardiac hypertrophy, fibrosis, and apoptosis, which resulted in the maintenance of cardiac function. The protective effects of ISL against inflammation and oxidative stress were mediated by the inhibition of mitogen-activated protein kinases (MAPKs) and induction of nuclear factor-erythroid 2 related factor 2 (Nrf2) signaling pathway, respectively. CONCLUSION: Our results provided compelling evidence that ISL, by virtue of neutralizing excessive inflammatory response and oxidative stress, could be a promising agent in the treatment of DCM. Targeting the MAPKs and Nrf2 signaling pathway might be an effective therapeutic strategy for the prevention and treatment of DCM.

Combined Inhibition of ATR and WEE1 as a Novel Therapeutic Strategy in Triple-Negative Breast Cancer.

Triple negative breast cancer (TNBC) is a highly aggressive subtype of breast cancer that poses a clinical challenge. Thus, new therapy strategies are urgently needed. The selective WEE1 inhibitor, AZD1775, has shown strong anti-proliferative effects on a variety of tumors. Here, we first demonstrate that inhibition of ATR by selective inhibitor AZD6738 can enhance AZD1775-caused growth inhibition in TNBC. Our results show that the enhanced cell death is attributed to repressed DNA damage repair and excessive replication stress, thereby causing increased DNA damage reflected by accumulation of the DNA double-strand-break marker γH2AX. On the other hand, combined treatment with AZD6738 and AZD1775 forces mitotic entry of cells with DNA damages by activating CDK1 activity, inducing severely aberrant mitosis and mitotic catastrophe, ultimately resulting in cell death. Dual inhibition of WEE1 and ATR also inactivated RAD51-mediated homologous recombination, which sensitized TNBC cells to cisplatin and PARP inhibitor. Here, based on the preclinical results that ATR inhibition synergizes with WEE1 inhibition in TNBC, we propose that this combination therapy alone, or in parallel with chemotherapy, represents an innovative and potent targeted therapy in TNBC.

miR-19b-3p inhibits breast cancer cell proliferation and reverses saracatinib-resistance by regulating PI3K/Akt pathway.

Breast cancer arises as the most frequent malignancy, and causes the majority of cancer death among females worldwide. Src is a tyrosine kinase identified as the product of the proto-oncogene and is supposed to promote cancer development and metastasis. Src inhibitors are recently developed and have shown efficacy in breast cancer. Increasing evidences suggest that aberrant expression of miRNAs is involved in cancer development and drug resistance. Identifying miRNAs associated with drug resistance may enhance the sensitivity of targeted therapies, including Src inhibitors. In this study, we established a Src inhibitor saracatinib-resistant breast cancer cell line (SK-BR-3/SI) for the first time. Microarray data and qRT-PCR results showed that miR-19b-3p expression was downregulated in saracatinib-resistant cells compared with saracatinib-sensitive cells. Downregulation of miR-19b-3p remarkably increased the IC50 value of saracatinib, and promoted cell migration. Further studies found that miR-19b-3p reduced PIK3CA expression by directly targeting PIK3CA gene and the resistance of Src inhibitor might be associated with activation of PI3K/Akt pathway after downregulation of miR-19b-3p. Moreover, we demonstrated that PI3K inhibitor LY294002 could reverse saracatinib resistance in saracatinib-resistant cells, which deserved further preclinical and clinical evaluation of dual inhibition of Src and PI3K in breast cancer.

Endothelial cells promote triple-negative breast cancer cell metastasis via PAI-1 and CCL5 signaling.

Endothelial cells (ECs) in the tumor microenvironment have been reported to play a more active role in solid tumor growth and metastatic dissemination than simply providing the physical structure to form conduits for blood flow; however, the involvement of ECs in the process of triple-negative breast cancer (TNBC) metastasis has not been addressed. Here, we demonstrate that ECs-when mixed with TNBC cells-could increase TNBC cell metastatic potency. After treatment with TGF-ß to induce endothelial-mesenchymal transition (EMT), TNBC cells could produce plasminogen activator inhibitor-1 (PAI-1) and stimulate the expression and secretion of the chemokine, CCL5, from ECs, which then acts in a paracrine fashion on TNBC cells to enhance their migration, invasion, and metastasis. CCL5, in turn, accelerates TNBC cell secretion of PAI-1 and promotes TNBC cell metastasis, thus forming a positive feedback loop. Moreover, this enhanced metastatic ability is reversible and dependent on CCL5 signaling via the chemokine receptor, CCR5. Of importance, key features of this pathway are manifested in patients with TNBC and in The Cancer Genome Atlas database. Taken together, our results suggest that ECs enhance EMT-induced TNBC cell metastasis via PAI-1 and CCL5 signaling and illustrate the potential of developing new PAI-1- and CCL5-targeting therapy for patients with TNBC.-Zhang, W., Xu, J., Fang, H., Tang, L., Chen, W., Sun, Q., Zhang, Q., Yang, F., Sun, Z., Cao, L., Wang, Y., Guan, X. Endothelial cells promote triple-negative breast cancer cell metastasis via PAI-1 and CCL5 signaling.

Intratumor heterogeneity predicts metastasis of triple-negative breast cancer.

Even with the identical clinicopathological features, the ability for metastasis is vastly different among triple-negative breast cancer (TNBC) patients. Intratumor heterogeneity (ITH), which is common in breast cancer, may be a key mechanism leading to the tumor progression. In this study, we studied whether a quantitative genetic definition of ITH can predict clinical outcomes in patients with TNBC. We quantified ITH by calculating Shannon index, a measure of diversity in a population, based on Myc, epidermal growth factor receptor/centromeric probe 7 (EGFR/CEP7) and cyclin D1/centromeric probe 11 (CCND1/CEP11) copy number variations (CNVs) in 300 cells at three different locations of a tumor. Among 75 TNBC patients, those who developed metastasis had significantly higher ITH, that is Shannon indices of EGFR/CEP7 and CCND1/CEP11 CNVs. Higher Shannon indices of EGFR/CEP7 and CCND1/CEP11 CNVs were significantly associated with the development of metastasis and were predictive of significantly worse metastasis-free survival (MFS). Regional heterogeneity, defined as the difference in copy numbers of Myc, EGFR or CCND1 at different locations, was found in 52 patients. However, the presence of regional heterogeneity did not correlate with metastasis or MFS. Our findings demonstrate that higher ITH of EGFR/CEP7 and CCND1/CEP11 CNVs is predictive of metastasis and is associated with significantly worse MFS in TNBC patients, suggesting that ITH is a very promising novel prognostic factor in TNBC.

Differential microRNA expression is associated with androgen receptor expression in breast cancer.

The androgen receptor (AR) is frequently expressed in breast cancer; however, its prognostic value remains unclear. AR expression in breast cancer has been associated with improved outcomes in estrogen receptor (ER)­positive breast cancer compared with ER­negative disease. Eliminating AR function in breast cancer is critically important for breast cancer progression. However, the mechanism underlying AR regulation remains poorly understood. The study of microRNAs (miRNAs) has provided important insights into the pathogenesis of hormone­dependent cancer. To determine whether miRNAs function in the AR regulation of breast cancer, the present study performed miRNA expression profiling in AR­positive and ­negative breast cancer cell lines. A total of 153 miRNAs were differentially expressed in AR­positive compared with AR­negative breast cancer cells; 52 were upregulated and 101 were downregulated. A number of these have been extensively associated with breast cancer cell functions, including proliferation, invasion and drug­resistance. Furthermore, through pathway enrichment analysis, signaling pathways associated with the prediction targets of the miRNAs were characterized, including the vascular endothelial growth factor and mammalian target of rapamycin signaling pathways. In conclusion, the results of the present study indicated that the expression of miRNAs may be involved in the mechanism underlying AR regulation of breast cancer, and may improve understanding of the role of AR in breast cancer.

The Correlation Between PARP1 and BRCA1 in AR Positive Triple-negative Breast Cancer.

Triple-negative breast cancer (TNBC) lacks estrogen receptor (ER), progesterone receptor (PR) and human epidermal growth factor receptor 2 (HER-2) expression and thus cannot benefit from conventional hormonal or anti-HER2 targeted therapies. Anti-androgen therapy has shown a certain effect on androgen receptor (AR) positive TNBC. The emerging researches have proved that poly (ADP-ribose) polymerase (PARP) inhibitor is effective in BRCA1-deficient breast cancers. We demonstrated that combination of AR antagonist (bicalutamide) and PARP inhibitor (ABT-888) could inhibit cell viability and induce cell apoptosis significantly whatever in vitro or in vivo setting in AR-positive TNBC. Previous studies have proved that both BRCA1 and PARP1 have close connections with AR in prostate cancer. We explored the correlation among AR, PARP1 and BRCA1 in TNBC for the first time. After BRCA1 overexpression, the expression of AR and PARP1 were decreased in mRNA and protein levels. Additionally, AR positively regulated PARP1 while PARP1 also up-regulated AR expression in vitro. We also confirmed BRCA1 expression was negatively correlated with AR and PARP1 in TNBC patients using a tissue microarray with TNBC patient samples. These results suggest that the combination of bicalutamide and PARP inhibitor may be a potential strategy for TNBC patients and merits further evaluation.

Evaluation of Breast Cancer Stem Cells and Intratumor Stemness Heterogeneity in Triple-negative Breast Cancer as Prognostic Factors.

Triple-negative breast cancer (TNBC) is a tumor subtype with aggressive behavior and poor clinical outcome for lacking effective therapies. Breast cancer stem cells (BCSCs) have been suggested to have tumor-initiating properties, but it remains unclear whether their presence contributes to the increased aggressiveness and poor prognosis of TNBC. Also, the breast cancers display frequent inter- and intra-tumor heterogeneity, which adds the complexity in diagnosis and predicting prognosis. Here we investigated the clinical relevance and prognostic value of the BCSC markers, CD44+/CD24-, aldehyde dehydrogenase family 1 member A1 (ALDH1A1) and CD133 in 88 TNBC cases. We found that a few patients displayed spatial heterogeneity of the BCSC markers in expression, which was defined as intratumor stemness heterogeneity (ITSH) below. There was no significant correlation between any BCSC marker alone or ITSH and progression-free survival (PFS). Interestingly, the combined BCSC phenotype by CD44+/CD24- and ALDH1A1 was significantly associated with worse PFS (P = 0.009). Further stratification analysis revealed that this combined BCSC phenotype was an independent prognostic factor for PFS in some subgroups. In conclusion, we demonstrated the existence of ITSH in TNBC and found that the ITSH as well as a single BCSC marker was not significantly associated with survival, whereas combing the analysis of BCSC markers could improve prognostic value. Our findings may lead to an improvement of prognostic indicators in TNBC.

Synthesis, Characterization, and Bactericidal Evaluation of Chitosan/Guanidine Functionalized Graphene Oxide Composites.

In response to the wide spread of microbial contamination induced by bacterial pathogens, the development of novel materials with excellent antibacterial activity is of great interest. In this study, novel antibacterial chitosan (CS) and polyhexamethylene guanidine hydrochloride (PHGC) dual-polymer-functionalized graphene oxide (GO) (GO-CS-PHGC) composites were designed and easily fabricated. The as-prepared materials were characterized by Fourier transform infrared (FTIR), X-ray photoelectron spectrometer (XPS), field emission scanning electron microscopy (FE-SEM), transmission electron microscope (TEM), thermogravimetric analysis (TGA) and Raman spectroscopy. Their antibacterial capability towards bacterial strains was also studied by incubating both Gram-negative bacteria and Gram-positive bacteria in their presence. More significantly, the synergistic antibacterial action of the three components was assayed, and the findings implied that the as-prepared GO-CS-PHGC shows enhanced antibacterial activity when compared to its single components (GO, CS, PHGC or CS-PHGC) and the mixture of individual components. Not only Gram-negative bacteria but also Gram-positive bacteria are greatly inhibited by GO-CS-PHGC composites. The minimum inhibitory concentration (MIC) value of GO-CS-PHGC against E. coli was 32 µg/mL. With the powerful antibacterial activity as well as its low cost and facile preparation, GO-CS-PHGC has potential applications as a novel antibacterial agent in a wide range of biomedical uses.

Skp2 is over-expressed in breast cancer and promotes breast cancer cell proliferation.

The F box protein Skp2 is oncogenic. Skp2 and Skp2B, an isoform of Skp2 are overexpressed in breast cancer. However, little is known regarding the mechanism by which Skp2B promotes the occurrence and development of breast cancer. Here, we determined the expression and clinical outcomes of Skp2 in breast cancer samples and cell lines using breast cancer database, and investigated the role of Skp2 and Skp2B in breast cancer cell growth, apoptosis and cell cycle arrest. We obtained Skp2 is significantly overexpressed in breast cancer samples and cell lines, and high Skp2 expression positively correlated with poor prognosis of breast cancer. Both Skp2 and Skp2B could promote breast cancer cell proliferation, inhibit cell apoptosis, change the cell cycle distribution and induce the increased S phase cells and therefore induce cell proliferation in breast cancer cells. Moreover, the 2 isoforms could both suppress PIG3 expression via independent pathways in the breast cancer cells. Skp2 suppressed p53 and inhibited PIG3-induced apoptosis, while Skp2B attenuated the function of PIG3 by inhibiting PHB. Our results indicate that Skp2 and Skp2B induce breast cancer cell development and progression, making Skp2 and Skp2B potential molecular targets for breast cancer therapy.

Analysis of different HER-2 mutations in breast cancer progression and drug resistance.

Studies over the last two decades have identified that amplified human epidermal growth factor receptor (HER-2; c-erbB-2, neu) and its overexpression have been frequently implicated in the carcinogenesis and prognosis in a variety of solid tumours, especially breast cancer. Lots of painstaking efforts were invested on the HER-2 targeted agents, and significantly improved outcome and prolonged the survival of patients. However, some patients classified as 'HER-2-positive' would be still resistant to the anti-HER-2 therapy. Various mechanisms of drug resistance have been illustrated and the alteration of HER-2 was considered as a crucial mechanism. However, systematic researches in regard to the HER-2 mutations and variants are still inadequate. Notably, the alterations of HER-2 play an important role in drug resistance, but also have a potential association with the cancer risk. In this review, we summarize the possible mutations and focus on HER-2 variants' role in breast cancer tumourigenesis. Additionally, the alteration of HER-2, as a potential mechanism of resistance to trastuzumab, is discussed here. We hope that HER-2 related activating mutations could potentially offer more therapeutic opportunities to a broader range of patients than previously classified as HER-2 overexpressed.