Inhibits Breast Cancer Progression Research Articles

Ibrutinib treatment inhibits breast cancer progression and metastasis by inducing conversion of myeloid-derived suppressor cells to dendritic cells

BackgroundIbrutinib is a Bruton’s tyrosine kinase (BTK) and interleukin-2-inducible kinase (ITK) inhibitor used for treating chronic lymphocytic leukaemia (CLL) and other cancers. Although ibrutinib is known to inhibit the growth of breast cancer cell growth in vitro, its impact on the treatment and metastasis of breast cancer is unclear.MethodsUsing an orthotopic mouse breast cancer model, we show that ibrutinib inhibits the progression and metastasis of breast cancer.ResultsIbrutinib inhibited proliferation of cancer cells in vitro, and Ibrutinib-treated mice displayed significantly lower tumour burdens and metastasis compared to controls. Furthermore, the spleens and tumours from Ibrutinib-treated mice contained more mature DCs and lower numbers of myeloid-derived suppressor cells (MDSCs), which promote disease progression and are linked to poor prognosis. We also confirmed that ex vivo treatment of MDSCs with ibrutinib switched their phenotype to mature DCs and significantly enhanced MHCII expression. Further, ibrutinib treatment promoted T cell proliferation and effector functions leading to the induction of antitumour TH1 and CTL immune responses.ConclusionsIbrutinib inhibits tumour development and metastasis in breast cancer by promoting the development of mature DCs from MDSCs and hence could be a novel therapeutic agent for the treatment of breast cancer.

FOXN4 Inhibits Breast Cancer Progression By Direct Activation Of P53.

BackgroundFork head domain-containing gene family (Fox) transcription factors, consisting of over 20 members, are involved in the progression of certain types of tumor. However, whether FOXN4 is involved in carcinogenesis and tumor progression is still unclear.PurposeIn this study, we investigated the clinicopathological significance and the underlying mechanism of FOXN4 in breast cancer.Methods and resultsWe examined the lower expression of FOXN4 in breast cancer tissues and cancer cell lines. The expression of FOXN4 is negatively correlated with tumor size and lymph node metastasis. Using CCK-8 assay, colony formation assay, wound healing assay, and Transwell assay, we revealed that FOXN4 notably decreased breast cancer cell proliferation, epithelial-mesenchymal transition and invasion in vitro. In addition, quantitative chromatin immunoprecipitation and luciferase assays determined that FOXN4 was able to directly bind with the promoter of P53. RT-qPCR and Western blotting analysis showed that FOXN4 could directly activate P53 expression. Functionally, P53 knockdown rescued the tumor inhibition effects of FOXN4 in breast cancer cells.ConclusionThe present study provides new insights into the role of FOXN4 in breast cancer progression and suggests FOXN4 might represent a potential therapeutic target in breast cancer by modulating P53.

ERK1 indicates good prognosis and inhibits breast cancer progression by suppressing YAP1 signaling.

The mitogen-activated protein kinase/extracellular signal-regulated (MAPK/ERK) pathway is a well-characterized signaling pathway during the development of various cancer types. ERK1 and ERK2, the two kinase effectors of MAPK cascade, exhibit high similarity. However, it is still unknown whether these two kinases are functionally different or in contrast functionally redundant during the development of breast cancer. We found that ERK1 expression levels were significantly lower in basal breast cancer compared with luminal breast cancer and normal breast tissues. RNA sequencing data suggested that ERK1 was associated with Hippo signaling pathway and cell proliferation in breast cancer cells. The gene set enrichment analysis (GSEA) further showed enrichment for YAP1 signaling pathway in breast cancer cell lines and tumors with low expression of ERK1. Silencing of ERK1 elevated YAP1 expression and TEAD activity in breast cancer cells. Additionally, ERK1 inhibited breast cancer cell proliferation via regulation of YAP1. The Kaplan-Meier analysis of data in patients with breast cancer suggested that, higher expression of ERK1 was associated with better prognosis, whereas, higher expression of ERK2 predicted poorer prognosis. These findings unveiled the role of ERK1 on regulation of YAP1 signaling pathway, indicating ERK1 as a negative regulator of breast cancer progression.

IL1R2 Blockade Suppresses Breast Tumorigenesis and Progression by Impairing USP15-Dependent BMI1 Stability.

Breast tumor initiating cells (BTICs) with ALDH+CD24−CD44+ phenotype are the most tumorigenic and invasive cell population in breast cancer. However, the molecular mechanisms are still unclear. Here, it is found that a negative immune regulator interleukin‐1 receptor type 2 (IL1R2) is upregulated in breast cancer (BC) tissues and especially in BTICs. BC patients with high IL1R2 expression have a poorer overall survival and relapse‐free survival. High IL1R2 promotes BTIC self‐renewal and BC cell proliferation and invasion. Mechanistically, IL1R2 is activated by IL1β, as demonstrated by the fact that IL1β induces the release of IL1R2 intracellular domain (icd‐IL1R2) and icd‐IL1R2 then interacts with the deubiquitinase USP15 at the UBL2 domain and promotes its activity, which finally induces BMI1 deubiquitination at lysine 81 and stabilizes BMI1 protein. In addition, IL1R2 neutralizing antibody can suppress the protein expression of both IL1R2 and BMI1, and significantly abrogates the promoting effect of IL1R2 on BTIC self‐renewal and BC cell growth both in vitro and in vivo. The current results indicate that blocking IL1R2 with neutralizing antibody provides a therapeutic approach to inhibit BC progression by targeting BTICs.

MRPS30-DT Knockdown Inhibits Breast Cancer Progression by Targeting Jab1/Cops5.

Longnoncoding RNAs (lncRNAs) are significantly correlated with cancer pathogenesis, development, and metastasis. Microarray analysis showed that lncRNA MRPS30-DT is overexpressed in breast carcinoma; however, the function of MRPS30-DT in breast cancer tumorigenesis remains unclear. In situ hybridization and immunohistochemical analysis were used to evaluate the expression levels of MRPS30-DT and Jab1 in clinical samples of breast carcinoma and their relation to survival outcome. qRT-PCR was used to measure MRPS30-DT and Jab1 mRNA expressions. Protein levels were detected using Western blot. Cell proliferation and invasion ability were evaluated via 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT), colony formation, and transwell assays. MRPS30-DT was knocked down in breast cancer cells to investigate its potential functional roles in cell growth and metastasis in vitro and in vivo. We found that MRPS30-DT was upregulated in breast cancer specimens and was accompanied by high Jab1 expression compared with that of paired para-carcinoma tissues. Knocking down MRPS30-DT significantly inhibited cancer cell proliferation and invasion and induced apoptosis in breast cancer cells. Similarly, knocking down MRPS30-DT in MDA-MB-231 cells significantly suppressed tumor growth. Furthermore, knocking down MRPS30-DT markedly reduced Jab1 expression in breast cancer cells and murine carcinoma. Statistical analyses suggested that high MRPS30-DT or Jab1 levels in breast cancer patients were positively correlated with poor prognoses. These data indicate the possible mechanisms of MRPS30-DT and Jab1 in breast cancer; thus, MRPS30-DT and Jab1 may be novel prognostic biomarkers and potential therapeutic targets for breast cancer treatment.

PPARγ inhibits breast cancer progression by upregulating PTPRF expression.

Peroxisome proliferator-activated receptor γ (PPARγ) regulates fatty acid storage and glucose metabolism. Recently, PPARγ has been reported to be involved in cancer. The present study reported a PPARγ consensus binding site (AGGTCA) in the ptprf promoter and identified a strong association between PPARγ and PTPRF expression, as well as their tumor suppressor roles in a v-Ha-Ras-induced model of breast cancer. The prognostic potential of PPARγ was assessed with a KM analysis of raw data from 3,951 breast cancer patients. The expression of PPARγ and PTPRF in the rat breast cancer cell lines was detected by Western blot and qPCR. The impact of PPARγ on cancer cell migration, invasion, and growth was confirmed using cell migration assay, transwell cell invasion assay, tri-dimensional soft agar culture, respectively. The binding of PPARγ with the ptprf promoter was then examined using electrophoretic mobility shift assay. The inhibitory effect of PPARγ on tumor growth was then examined in mouse tumor model in vivo. It was identified that PPARγ expression is lost in the aggressive v-Ha-Ras-induced breast cancer cell line FE1.2 but highly expressed in less malignant FE1.3 cells. Exogenous expression of PPARγ in FE1.2 cells (FE1.2-PPARγhi) resulted in a marked inhibition of proliferation compared with that in FE1.2-Vector control group. FE1.2-PPARγhi cells also exhibited reduced migration, invasion, and colony formation abilities compared with those of the controls. The PPARγ agonist rosiglitazone also suppressed the malignant properties of FE1.2 cells. Protein tyrosine phosphatase receptor F (PTPRF), a downstream target of PPARγ, was markedly induced in FE1.2-PPARγhi cells. A PPARγ consensus binding site (AGGTCA) was identified in the ptprf promoter, and an electrophoretic mobility shift assay confirmed that PPARγ bind to this promoter. Similar to the effect of vector-mediated overexpression of PPARγ, ectopic overexpression of PTPRF in FE1.2 cells led to reduced proliferation. Furthermore, a PPARγ antagonist (GW9662) and PTP inhibitor (NSC87877) abrogated the suppressive function of PPARγ and PTPRF in FE1.2 cells, respectively. PPARγ overexpression or activation suppressed the progression and distant organ metastasis of breast cancer cells in a NOD/SCID mouse model. These results suggest that PPARγ inhibits tumor cell proliferation, at least in part, through direct regulation of the ptprf gene and that PPARγ is a potential target for breast cancer treatment.

Cardamonin inhibits breast cancer growth by repressing HIF-1\u03b1-dependent metabolic reprogramming

BackgroundCardamonin, a chalcone isolated from Alpiniae katsumadai, has anti-inflammatory and anti-tumor activities. However, the molecular mechanism by which cardamonin inhibits breast cancer progression largely remains to be determined.MethodsCCK-8 and Hoechst 33258 staining were used to detect cell growth and apoptosis, respectively. HIF-1α driven transcription was measured by luciferase reporter assay. Glucose uptake and lactate content were detected with 2-NBDG and L-Lactate Assay Kit. Cell metabolism assays were performed on Agilent’s Seahorse Bioscience XF96 Extracellular Flux Analyzer. Mitochondrial membrane potential was measured with JC-1 probe. DCFH-DA was used to measure ROS level. Protein expression was detected by western blotting assay. Immunohistochemistry was performed to measure the expression of HIF-1α, LDHA and CD31 in tumor tissues.ResultsCardamonin inhibited growth of the triple negative breast cancer cell line MDA-MB-231 in vitro and in vivo by suppressing HIF-1α mediated cell metabolism. Cardamonin inhibited the expression of HIF-1α at mRNA and protein levels by repressing the mTOR/p70S6K pathway, and subsequently enhanced mitochondrial oxidative phosphorylation and induced reactive oxygen species (ROS) accumulation. We also found that cardamonin inhibited the Nrf2-dependent ROS scavenging system which further increased intracellular ROS levels. Eventually, accumulation of the intracellular ROS induced apoptosis in breast cancer cells. In addition, cardamonin treatment reduced glucose uptake as well as lactic acid production and efflux, suggesting its function in repressing the glycolysis process.ConclusionsThese results reveal novel function of cardamonin in modulating cancer cell metabolism and suppressing breast cancer progression, and suggest its potential for breast cancer treatment.

The Inhibitory Effect of (-)-Epigallocatechin-3-Gallate on Breast Cancer Progression via Reducing SCUBE2 Methylation and DNMT Activity.

Epigenetic modifications are important mechanisms responsible for cancer progression. Accumulating data suggest that (−)-epigallocatechin-3-gallate (EGCG), the most abundant catechin of green tea, may hamper carcinogenesis by targeting epigenetic alterations. We found that signal peptide-CUB (complement protein C1r/C1s, Uegf, and Bmp1)-EGF (epidermal growth factor) domain-containing protein 2 (SCUBE2), a tumor suppressor gene, was hypermethylated in breast tumors. However, it is unknown whether EGCG regulates SCUBE2 methylation, and the mechanisms remain undefined. This study was designed to investigate the effect of EGCG on SCUBE2 methylation in breast cancer cells. We reveal that EGCG possesses a significantly inhibitory effect on cell viability in a dose- and time-dependent manner and presents more effects than other catechins. EGCG treatment resulted in enhancement of the SCUBE2 gene, along with elevated E-cadherin and decreased vimentin expression, leading to significant suppression of cell migration and invasion. The inhibitory effect of EGCG on SCUBE2 knock-down cells was remarkably alleviated. Further study demonstrated that EGCG significantly decreased the SCUBE2 methylation status by reducing DNA methyltransferase (DNMT) expression and activity. In summary, this study reported for the first time that SCUBE2 methylation can be reversed by EGCG treatment, finally resulting in the inhibition of breast cancer progression. These results suggest the epigenetic role of EGCG and its potential implication in breast cancer therapy.

Abstract 162: ASB13 inhibits breast cancer progression and metastasis through SNAI2 degradation and transcriptional regulation of YAP

Abstract Metastasis is responsible for the majority of cancer-related deaths. The transcription factor SNAI2 promotes metastasis by facilitating tumor cell invasion and tumor initiating activity. However, its post-translational regulation is less studied. We performed a dual luciferase-based, genome-wide E3 ligase siRNA library screening and identified ASB13 as an E3 ubiquitin ligase that targets SNAI2 for ubiquitination and degradation. ASB13 knockout in breast cancer cells leads to increased cell migration and decreased F-actin polymerization; while overexpression of ASB13 suppresses lung metastasis formed by LM2 cells. Furthermore, we discovered that ASB13 knockout decreases YAP expression, which is dependent on increased SNAI2 protein level. YAP functions as a tumor suppressor gene in breast cancer, as YAP knockout increases tumorsphere formation, anchorage-independent colony formation, and cell migration. Clinical data analysis reveals that ASB13 expression is positively correlated with overall survival in breast cancer patients. These findings establish the ASB13-SNAI2-YAP axis as a regulatory mechanism for breast cancer migration and metastasis. Citation Format: Huijuan Fan, Xuxiang Wang, Wenyang Li, Minhong Shen, Yong Wei, Hanqiu Zheng, Yibin Kang. ASB13 inhibits breast cancer progression and metastasis through SNAI2 degradation and transcriptional regulation of YAP [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 162.

The concurrent effects of azurin and Mammaglobin-A genes in inhibition of breast cancer progression and immune system stimulation in cancerous BALB/c mice.

In the present study, the simultaneous application of azurin gene of P. aeruginosa and MAM-A antigen on the induction of immune responses against breast cancer tumors was investigated in BALB/c mice. The pBudCE4.1-azurin-MAM-A recombinant vector was generated and prepared at a large scale. This recombinant vector alone or combined with chitosan nanoparticles was infused into the hip muscle of animals. Animals were divided into the "prevention" and "therapy" categories. The animals of prevention category were first, immunized by a recombinant vector and then exposed to chemical cancer inducers; while the animals in the therapy category were first treated with chemical compounds and then infused by a recombinant plasmid. The tumor tissues, infusion sites, and blood specimens were collected and examined by serological, molecular, and histological tests. The breast tumor incidence in the infused animals by recombinant plasmid alone or combined with nanoparticles (in both prevention and therapy categories) compared with infused mice by empty pBudCE4.1 vector was significantly decreased (p < 0.05). These results were supported by histological studies using H&E staining. The ELISA and q-real-time PCR techniques showed the range of IFN-γ, IL-12, IL-4, and IL-17A cytokines in the infused mice by recombinant vector alone or combined with nanoparticles compared to the healthy mice and infused animals by intact pBudCE4.1 were significantly increased (p < 0.05). Accordingly, the expression of the tumor markers CEA, Krt20, and Muc1 were significantly decreased in treated mice either by the sole recombinant vector or combined with nanoparticles (p < 0.05). These findings indicated that pBudCE4.1-azurin-MAM-A recombinant vector plays an essential role against the formation and expansion of breast tumors in the animal model. In addition, this recombinant vector is safe and has the proper ability to stimulate the immune system. In addition, the chitosan nanoparticle represents a promising adjuvant for DNA vaccine delivery, which improves the immune system stimulation and boosts the vaccine performance.

1954-P: Combined Treatment with Exendin-4 and Metformin Attenuates Breast Cancer Growth

Cancer is a major cause of death in patients with diabetes. Incretin therapy has received much attention, because of its tissue protective effects beyond glycemic control. We have previously reported anti-prostate cancer effect of Ex-4 and metformin (Diabetes 2014, PLOS ONE 2015). In addition, we have recently reported that Ex-4 attenuates breast cancer growth (Endocrinology 2017). Then, we next examined the effect of combined treatment of Ex-4 with Metformin in breast cancer. In human breast cancer cell lines, MCF-7, MDA-MB-231 and KPL-1 cells, Ex-4 or metformin reduced cell number in a dose-dependent manner. Further, combined treatment of Metformin and Ex-4 additively attenuated the growth curve progression of breast cancer cells. In BrdU assay, Ex-4 or Metformin significantly decreased breast cancer cell proliferation, and further reduction of BrdU incorporation was observed by combined treatment with Ex-4 and Metformin, suggesting that Ex-4 and Metformin additively decreased DNA synthesis in breast cancer cells. Although apoptotic cells were not observed in Ex-4 treated breast cancer cells, apoptotic cells were clearly detected in metformin treated breast cancer cells in TUNEL assay. Further, the experiments using xenograft model mice transplanting MCF-7 cells into athymic mice revealed that Ex-4 and metformin additively attenuated breast cancer growth in vivo also. These data suggest that Ex-4 and metformin attenuates breast cancer cell proliferation and metformin induces apoptosis in breast cancer cells and combined treatment with Ex-4 and metformin could be an optional therapy to inhibit breast cancer progression. Disclosure Y. Fujimura: None. T. Nomiyama: None. C. Iwaya: None. T. Kawanami: None. Y. Hamaguchi: None. T. Tanaka: None. T. Yanase: None.

A Perspective Review on the Role of Nanomedicine in the Modulation of TNF-TNFR2 Axis in Breast Cancer Immunotherapy.

In the past decade, nanomedicine research has provided us with highly useful agents (nanoparticles) delivering therapeutic drugs to target cancer cells. The present review highlights nanomedicine applications for breast cancer immunotherapy. Recent studies have suggested that tumour necrosis factor (TNF) and its receptor 2 (TNFR2) expressed on breast cancer cells have important functional consequences. This cytokine/receptor interaction is also critical for promoting highly immune-suppressive phenotypes by regulatory T cells (Tregs). This review generally provides a background for nanoparticles as potential drug delivery agents for immunomodulators and further discusses in depth the potential of TNF antagonists delivery to modulate TNF-TNFR2 interactions and inhibit breast cancer progression.

Producing the sour cherry pit oil nanoemulsion and evaluation of its anti-cancer effects on both breast cancer murine model and MCF-7 cell line

Aims: The sour cherry pit oil (SCPO) displays the potent anti-inflammatory, and antioxidant activities. In the present study, we have produced the SCPO nanoemulsion (SCPO-NE) to evaluate their anticancer impacts on breast cancer comparing with its un-processed oil.Methods: We employed an ultrasonication method to formulate the stable SCPO-NE. Their size, stability, and morphology were measured. Then, their cytotoxic impacts and apoptotic activity were checked on MCF7 breast cancer cells and compared with the normal Human foreskin fibroblasts (HFF). Finally, their anti-tumour effect was studied on murine breast cancer model (inoculated with TUBO cancer cells).Results: The results indicated the 36.5 nm stable SCPO-NE significantly decreased the MCF7 cells viability comparing with normal HFF cells, and reduced the tumour size in the murine model.Conclusion: We suggest that SCPO-NEs are able to efficiently inhibit breast cancer progression in both MCF7 cells and murine breast cancer model through apoptotic death induction.

Enriched environment inhibits breast cancer progression in obese models with intact leptin signaling.

Obesity is becoming a global epidemic and is a risk factor for breast cancer. Environmental enrichment (EE), a model recapitulating an active lifestyle, leads to leanness, resistance to diet-induced obesity (DIO) and cancer. One mechanism is the activation of the hypothalamic-sympathoneural-adipocyte (HSA) axis. This results in the release of norepinephrine onto adipose tissue inducing a drop of leptin. This study aimed to test the effects of EE on breast cancer onset and progression while considering the effect of leptin by utilizing the transgenic MMTV-PyMT model as well as several models of varied leptin signaling. EE was highly effective at reducing weight gain, regardless of the presence of leptin. However, the effects of EE on tumor progression were dependent on leptin signaling. EE decreased leptin and reduced mammary tumor growth rate in MMTV-PyMT spontaneous and DIO transplantation models; in contrast, the absence of leptin in ob/ob mice resulted in increased tumor growth likely due to elevated norepinephrine levels. Our results suggest that the microenvironment is critical in breast tumorigenesis and that the drop in leptin is an important peripheral mediator of the EE anti-breast cancer effects, offsetting the potential pro-tumorigenic effects of norepinephrine responding to a complex environment.

Salinomycin inhibits breast cancer progression via targeting HIF-1α/VEGF mediated tumor angiogenesis in vitro and in vivo

Cancer is a complex disease wherein cells begin to divideabnormally and spread into surrounding tissues. Angiogenesis plays a crucial role in tumor progression as it is required for sustained growth and metastasis, therefore targeting angiogenesis is a promising therapeutic approach for breast cancer management. Salinomycin (SAL) has been reported to exhibit anticancer response on various types of cancer. In the present study, we explored the antiangiogenic and anticancer efficacy of the polyether ionophore SAL in the breast cancer model. It effectively inhibited cell proliferation, invasion, and migration. It also inhibited the expression of pro-angiogenic cell surface marker CD31 in HUVEC, thereby interrupting the endothelial tubulogenesis. It decreased the HIF-1α transcription factor DNA binding activity to HRE sequence in HUVEC and human breast cancer cells. Further, corresponding to our in vitro findings, SAL suppressed neovascularization in the chick chorioallantoic membrane and the Matrigel plug implanted mice model. Bioluminescence and immunofluorescence imaging revealed that SAL treatment in mice inhibits breast cancer growth and tumor angiogenesis. SAL also suppressed the serum VEGFA level in tumor-bearing mice and induced caspase-dependent apoptosis in breast cancer cells. Taken together our findings suggested that SAL inhibits VEGF induced angiogenesis and breast cancer growth via interrupting HIF-1α/VEGF signalling and could be used as a promising antiangiogenic agent for breast cancer treatment.

YAP1 overexpression is associated with poor prognosis of breast cancer patients and induces breast cancer cell growth by inhibiting PTEN.

YES‐associated protein 1 (YAP1) plays a key role as a transcriptional coactivator in the Hippo tumor suppressor pathway. YAP1 is overexpressed in a variety of cancers and is considered to be encoded by a proto‐oncogene. However, the role of YAP1 remains debatable, because both gain and loss of YAP1 expression have both been reported in breast cancer (BC). Here, we found that elevated expression of YAP1 mRNA in BC was negatively correlated with relapse‐free, distant metastases‐free and overall survival rates. We then knocked down or overexpressed YAP1 in human BC cells, and examined cell proliferation, apoptosis, and tumorigenic ability in vivo. We identified that YAP1 promotes cell growth and inhibits cell apoptosis of BC through the phosphatase and tensin homolog deleted on chromosome 10–AKT signaling pathway, and thus suggest that YAP1 might serve as a new target for inhibiting BC progression.

Downregulation of long non-coding RNA Opa interacting protein 5-antisense RNA 1 inhibits breast cancer progression by targeting sex-determining region Y-box 2 by microRNA-129-5p upregulation.

Several studies have shown an important role for long non‐coding RNA (lncRNA) in breast cancer progression. The present study investigated the role of lncRNA Opa interacting protein 5‐antisense RNA 1 (OIP5‐AS1) in the progression of breast cancer. OIP5‐AS1 was significantly upregulated in breast cancer tissues and in breast cancer cell lines, and OIP5‐AS1 downregulation inhibited the malignant behavior of breast cancer in vitro and in vivo. For in‐depth exploration of the mechanism of OIP5‐AS1 in breast cancer, we found that expression of microRNA‐129‐5p(miR‐129‐5p), which was found to bind sites in the sequence of OIP5‐AS1, in breast cancer tissues was negatively correlated with OIP5‐AS1. Also, luciferase assays indicated that OIP5‐AS1 acted as a miR‐129‐5p sponge, resulting in upregulated expression of the sex‐determining region Y‐box 2 (SOX2) transcription factor. Our study showed that OIP5‐AS1 plays a critical role in promoting breast cancer progression and that OIP5‐AS1 downregulation targets SOX2 by miR‐129‐5p upregulation.

Knockdown of SETDB1 inhibits breast cancer progression by miR-381-3p-related regulation

BackgroundSET domain bifurcated 1 (SETDB1) has been widely considered as an oncogene playing a critical role in many human cancers, including breast cancer. Nevertheless, the molecular mechanism by which SETDB1 regulates breast cancer tumorigenesis is still unknown.MethodsqRT-PCR assay or western blot analysis was performed to assess the expression level of SETDB1 mRNA or protein, respectively. siSETDB1, pCMV6-XL5-SETDB1, miR-381-3p mimic, or miR-381-3p inhibitor was transfected into cells to regulate the expression of SETDB1 or miR-381-3p. MiRNA directly interacted with SETDB1 was verified by luciferase reporter assay and RNA immunoprecipitation. CCK-8 assay, colony formation assay, flow cytometric analysis, and transwell assay were used to detect the abilities of cell proliferation, cell cycle progression and migration, respectively. Animal model of xenograft tumor was used to observe the regulatory effect of SETDB1 on tumor growth in vivo.ResultsWe verified that SETDB1 mRNA level was upregulated in breast cancer tissues and cell lines, and SETDB1 depletion led to a suppression of cell proliferation, cell cycle progression and migration in vitro, as well as tumor growth in vivo. SETDB1 was verified to be a target of miR-381-3p. Moreover, miR-381-3p overexpression suppressed cell proliferation, cell cycle progression and migration, whereas SETDB1 abated miR-381-3p-mediated regulatory function on breast cancer cells.ConclusionsThis study revealed that SETDB1 knockdown might suppress breast cancer progression at least partly by miR-381-3p-related regulation, providing a novel prospect in breast cancer therapy.

Lobaplatin inhibits breast cancer progression, cell proliferation while it induces cell apoptosis by downregulating MTDH expression.

ObjectiveLobaplatin shows antitumor activity against a wide range of tumors, including metastatic breast cancer (BCa). The overexpression of metadherin (MTDH) is associated with poor prognosis of BCa patients. This study was designed to investigate the effect of lobaplatin on MCF-7 cell proliferation and its association with MTDH expression.Patients and methodsClinical treatment for BCa using lobaplatin, in combination with other general chemotherapy drugs, was administered to 32 BCa patients. The safety, effectiveness, and prognosis in lobaplatin-treated BCa patients were compared with those in controls (n=32). In vitro experiments were performed in MCF-7 cells to investigate the effect of lobaplatin on cell proliferation, apoptosis, and MTDH expression.ResultsWe found the intraoperative local chemotherapy using lobaplatin was safe and effective for BCa treatment, in comparison with the patients administered general chemotherapy drugs. Treatment of MCF-7 cell cultures with lobaplatin significantly reduced cell proliferation and increased cell apoptotic percentage. The expression of MTDH and Bcl-2 was inhibited by lobaplatin and that of Bax was increased by lobaplatin. Moreover, we observed the inhibition of MTDH by shRNA reduced cell proliferation and enhanced cell apoptosis.ConclusionLobaplatin was a safe and effective adjuvant chemotherapy for BCa. The effect of lobaplatin on inhibiting MCF-7 cell proliferation and inducing cell apoptosis might be, as least in part, mediated by suppressing the expression of oncogene MTDH.

Signaling network involved in the GPC3-induced inhibition of breast cancer progression: role of canonical Wnt pathway.

We have shown that GPC3 overexpression in breast cancer cells inhibits in vivo tumor progression, by acting as a metastatic suppressor. GPC3-overexpressing cells are less clonogenic, viable and motile, while their homotypic adhesion is increased. We have presented evidences indicating that GPC3 inhibits canonical Wnt and Akt pathways, while non-canonical Wnt and p38MAPK cascades are activated. In this study, we aimed to investigate whether GPC3-induced Wnt signaling inhibition modulates breast cancer cell properties as well as to describe the interactions among pathways modulated by GPC3. Fluorescence microscopy, qRT-PCR microarray, gene reporter assay and Western blotting were performed to determine gene expression levels, signaling pathway activities and molecule localization. Lithium was employed to activate canonical Wnt pathway and treated LM3-GPC3 cell viability, migration, cytoskeleton organization and homotypic adhesion were assessed using MTS, wound healing, phalloidin staining and suspension growth assays, respectively. We provide new data demonstrating that GPC3 blocks-also at a transcriptional level-both autocrine and paracrine canonical Wnt activities, and that this inhibition is required for GPC3 to modulate migration and homotypic adhesion. Our results indicate that GPC3 is secreted into the extracellular media, suggesting that secreted GPC3 competes with Wnt factors or interacts with them and thus prevents Wnt binding to Fz receptors. We also describe the complex network of interactions among GPC3-modulated signaling pathways. GPC3 is operating through an intricate molecular signaling network. From the balance of these interactions, the inhibition of breast metastatic spread induced by GPC3 emerges.