Yayun Chi

Induction of miRNA-181a by genotoxic treatments promotes chemotherapeutic resistance and metastasis in breast cancer

Acquired therapeutic resistance is the major drawback to effective systemic therapies for cancers. Aggressive triple-negative breast cancers (TNBC) develop resistance to chemotherapies rapidly, whereas the underlying mechanisms are not completely understood. Here we show that genotoxic treatments significantly increased the expression of miR-181a in TNBC cells, which enhanced TNBC cell survival and metastasis upon Doxorubicin treatment. Consistently, high miR-181a level associated with poor disease free survival and overall survival after treatments in breast cancer patients. The upregulation of miR-181a was orchestrated by transcription factor STAT3 whose activation depended on NF-κB-mediated IL-6 induction in TNBC cells upon genotoxic treatment. Intriguingly, activated STAT3 not only directly bound to MIR181A1 promoter to drive transcription but also facilitated the recruitment of MSK1 to the same region where MSK1 promoted a local active chromatin state by phosphorylating histone H3. We further identified BAX as a direct functional target of miR-181a, whose suppression decreased apoptosis and increased invasion of TNBC cells upon Dox treatment. These results were further confirmed by evidence that suppression of miR-181a significantly enhanced therapeutic response and reduced lung metastasis in a TNBC orthotopic model. Collectively, our data suggested that miR-181a induction had a critical role in promoting therapeutic resistance and aggressive behavior of TNBC cells upon genotoxic treatment. Antagonizing miR-181a may serve as a promising strategy to sensitize TNBC cells to chemotherapy and mitigate metastasis.

MiRNA-621 sensitizes breast cancer to chemotherapy by suppressing FBXO11 and enhancing p53 activity

MicroRNAs (miRNAs) have been demonstrated to have critical roles in regulating cancer cell proliferation, survival and sensitivity to chemotherapy. The potential application of using miRNAs to predict therapeutic response to cancer treatment holds high promise, but miRNAs with predictive value remain to be identified and underlying mechanisms have not been completely understood. Here, we show a strong correlation between miR-621 expression and chemosensitivity to paclitaxel plus carboplatin (PTX/CBP) regimen, an effective neoadjuvant chemotherapy for breast cancer patients. High level of miR-621 predicts better response to PTX/CBP regimen neoadjuvant chemotherapy in breast cancer patients, who also tend to achieve pathological complete response. Ectopic overexpression of miR-621 promoted apoptosis and increased chemosensitivity to PTX and CBP both in cultured breast cancer cells and in xenograft tumor model. We further show that FBXO11 is a direct functional target of miR-621 and miR-621 level is negatively correlated with FBXO11 expression in breast cancer patients. Ectopic expression of FBXO11 attenuated increased apoptosis in breast cancer cells overexpressing miR-621 upon PTX or CBP treatment. Consistently, high FBXO11 expression significantly correlated with poor survival in breast cancer patients. Mechanistically, we found in breast cancer cells FBXO11 interacts with p53 and promotes its neddylation, which suppressed the p53 transactivity. Accordingly, miR-621-dependent FBXO11 suppression enhanced p53 activity and increased apoptosis in breast cancer cells exposed to chemotherapeutics. Taken together, our data suggest that miR-621 enhances chemosensitivity of breast cancer cells to PTX/CBP chemotherapy by suppressing FBXO11-depedent inhibition of p53. miR-621 may serve as a predictive biomarker and a potential therapeutic target in breast cancer treatment.

Long non-coding RNA metastasis associated in lung adenocarcinoma transcript 1 (MALAT1) interacts with estrogen receptor and predicted poor survival in breast cancer

Metastasis associated in lung adenocarcinoma transcript 1 (MALAT1), a lncRNA that was first recognized as a prognostic parameter for patient survival of stage I lung cancer, is up-regulated in multiple human malignancies, including breast cancer. However, the mechanism of its function remained elusive. In the current study, by examining MALAT1 expression on mRNA level, we demonstrated that compared with MCF10A, MALAT1 expression was up-regulated in the majority of breast cancer cell lines (9/12). In 26 pairs of estrogen receptor (ER)-positive breast cancer samples, MALAT1 expression was significantly up-regulated compared with adjacent normal tissues (P = 0.012). Furthermore, of 204 breast cancer patients, high MALAT1 expression was associated with positive ER (P = 0.023) and progesterone receptor (PR) (P = 0.024) status. Further analysis using TCGA database revealed that ER and its target genes PGR and CCND1, were overexpressed in MALAT1 altered group compared with unaltered group, both on the mRNA and protein level. Lastly, we verified MALAT1s prognostic value in breast cancer. At the cut-off value of 75%, MALAT1 was the only independent prognostic factor of recurrence-free survival (RFS) in ER-negative patients in a multivariate Cox regression model (hazard ratio [HR] = 2.83, 95% confidence interval [CI] 1.02–7.83). MALAT1 overexpression was also associated with poor RFS in tamoxifen treated ER-positive breast cancer patients, which might serve as a potential biomarker to predict endocrine treatment sensitivity.

DIXDC1 activates the Wnt signaling pathway and promotes gastric cancer cell invasion and metastasis

DIXDC1 (Dishevelled‐Axin domain containing 1) is a DIX (Dishevelled‐Axin) domain‐possessing protein that promotes colon cancer cell proliferation and increases the invasion and migration ability of non‐small‐cell lung cancer via the PI3K pathway. As a positive regulator of the Wnt/β‐catenin pathway, the biological role of DIXDC1 in human gastric cancer and the relationship between DIXDC1 and the Wnt pathway are unclear. In the current study, the upregulation of DIXDC1 was detected in gastric cancer and was associated with advanced TNM stage cancer, lymph node metastasis, and poor prognosis. We also found that the overexpression of DIXDC1 could promote the invasion and migration of gastric cancer cells. The upregulation of MMPs and the downregulation of E‐cadherin were found to be involved in the process. DIXDC1 enhanced β‐catenin nuclear accumulation, which activated the Wnt pathway. Additionally, the inhibition of β‐catenin in DIXDC1‐overexpressing cells reversed the metastasis promotion effects of DIXDC1. These results demonstrate that the expression of DIXDC1 is associated with poor prognosis of gastric cancer patients and that DIXDC1 promotes gastric cancer invasion and metastasis through the activation of the Wnt pathway; E‐cadherin and MMPs are also involved in this process.

Identification of a comprehensive spectrum of genetic factors for hereditary breast cancer in a Chinese population by next-generation sequencing

The genetic etiology of hereditary breast cancer has not been fully elucidated. Although germline mutations of high-penetrance genes such as BRCA1/2 are implicated in development of hereditary breast cancers, at least half of all breast cancer families are not linked to these genes. To identify a comprehensive spectrum of genetic factors for hereditary breast cancer in a Chinese population, we performed an analysis of germline mutations in 2,165 coding exons of 152 genes associated with hereditary cancer using next-generation sequencing (NGS) in 99 breast cancer patients from families of cancer patients regardless of cancer types. Forty-two deleterious germline mutations were identified in 21 genes of 34 patients, including 18 (18.2%) BRCA1 or BRCA2 mutations, 3 (3%) TP53 mutations, 5 (5.1%) DNA mismatch repair gene mutations, 1 (1%) CDH1 mutation, 6 (6.1%) Fanconi anemia pathway gene mutations, and 9 (9.1%) mutations in other genes. Of seven patients who carried mutations in more than one gene, 4 were BRCA1/2 mutation carriers, and their average onset age was much younger than patients with only BRCA1/2 mutations. Almost all identified high-penetrance gene mutations in those families fulfill the typical phenotypes of hereditary cancer syndromes listed in the National Comprehensive Cancer Network (NCCN) guidelines, except two TP53 and three mismatch repair gene mutations. Furthermore, functional studies of MSH3 germline mutations confirmed the association between MSH3 mutation and tumorigenesis, and segregation analysis suggested antagonism between BRCA1 and MSH3. We also identified a lot of low-penetrance gene mutations. Although the clinical significance of those newly identified low-penetrance gene mutations has not been fully appreciated yet, these new findings do provide valuable epidemiological information for the future studies. Together, these findings highlight the importance of genetic testing based on NCCN guidelines and a multi-gene analysis using NGS may be a supplement to traditional genetic counseling.

Role of BC040587 as a predictor of poor outcome in breast cancer.

BackgroundAccumulating studies have focused on the oncogenic and tumor suppressive roles of the newly identified lncRNAs. A novel lncRNA BC040587 in 3q13.31 locus which exists frequent copy number alterations was found to be associated with poor survival of osteosarcoma patients. However, its role in breast cancer (BC) remains unknown. The aim of this study was to examine the expression pattern of BC040587 in BC and to evaluate its biological role and clinical significance in prediction of prognosis.MethodsExpression of BC040587 was analyzed in 20 pairs of BC cancer tissues and adjacent noncancerous tissues (ANCT), also in 151 BC tissues, 9 BC cell lines and one normal breast cell line by quantitative reverse-transcription polymerase chain reaction (qRT-PCR). Differences between groups were tested for significance using Student’s t-test (two-tailed). Then we analyzed the potential relationship between BC040587 expression and clinic pathological features of BC patients. The correlation was analyzed by SPSS software.ResultsIt showed that BC040587 expression was down regulated both in BC samples and in BC cell lines compared with corresponding normal control. BC040587 expression was correlated with menopausal status (p = 0.040) and tumor differentiation (p = 0.035). The Kaplan-Meier survival curves indicated that the overall survival (OS) was significantly poor in low BC040587 expression BC patients (p = 0.023). Furthermore, expression of BC040587 was significantly associated with worse prognosis and was shown to be an independent prognostic marker breast cancer (p = 0.032). Our studies indicate that BC040587 may represent a new marker of prognosis in breast cancer.ConclusionOur studies indicate that BC040587 is significantly down-regulated in BC tissues and BC cell lines. BC040587 may represent a new marker of prognosis in breast cancer.

CDK11p58 inhibits ERα-positive breast cancer invasion by targeting integrin β3 via the repression of ERα signaling

BackgroundCDK11p58, a Ser/Thr kinase that belongs to the cell division cycle 2-like 1 (CDC2L1) subfamily, is associated with cell cycle progression, tumorigenesis and apoptotic signaling. CDK11p58 is also involved in the regulation of steroid receptors, such as androgen and estrogen receptors. We previously found that CDK11p58 was abnormally expressed in prostate cancer. However, its role in breast cancer remains unclear.MethodsCDK11p58 expression was evaluated by immunohistochemical staining in a tissue array. A Transwell assay was used to detect invasion and metastasis in breast cancer cells. The TaqMan® Metastasis Gene Expression Assay was used to search for potential downstream factors in the CDK11p58 signaling pathway. qRT-PCR was used to evaluate mRNA levels, and the dual luciferase array was used to analyze promoter activity. Western blotting was used to detect the protein level.ResultsCDK11p58 expression was negatively correlated with node status (P = 0.012), relapse status (P = 0.002) and metastasis status (P = 0.023). Kaplan-Meier survival curves indicated that the disease-free survival (DFS) was significantly poor in breast cancer patients with low CDK11 expression. Interestingly, using the breast cancer cell lines ZR-75-30 and MDA-MB-231, we found that CDK11p58 was capable of repressing the migration and invasion of ERα-positive breast cancer cells, but not ERα-negative breast cancer cells, in a kinase-dependent manner. Gene expression assays demonstrated that integrin β3 mRNA was dramatically repressed by CDK11p58, and luciferase results confirmed that the integrin β3 promoter was inhibited by CDK11p58 through ERα repression. The expression of integrin β3 was highly related to ERα signaling; ERα overexpression stimulated integrin β3 expression, whereas siRNA-mediated knockdown of ERα attenuated integrin β3 expression.ConclusionsThese data indicate that CDK11p58 is an anti-metastatic gene in ERα-positive breast cancer and that the regulation of integrin β3 by CDK11p58 via the repression of ERα signaling may constitute part of a signaling pathway underlying breast cancer invasion.

LINC00978 predicts poor prognosis in breast cancer patients

Breast cancer is the most frequently diagnosed cancer and the leading cause of cancer death among women worldwide. Long non-coding RNAs (lncRNAs) are a class of non-coding RNAs in the human genome that involves in breast cancer development and progression. Here, we identify a lncRNA, LINC00978, which is upregulated in breast cancer cell lines and tissues compared with corresponding controls. Furthermore, LINC00978 expression is negatively associated with hormone receptor (HR) status in 195 breast cancer patients studied (p = 0.033). Kaplan–Meier survival analysis shows that patients with high LINC00978 expression have poorer disease-free survival (DFS) than those with low LINC00978 expression (p = 0.012), and multivariate analysis identifies LINC00978 as an independent prognostic factor in breast cancer (p = 0.008, hazard ratio [HR] = 2.270, 95% confidence interval [CI] 1.237–4.165). Our study indicates that LINC00978 may be an oncogene in breast cancer, and can serve as a potential biomarker to predict prognosis in breast cancer patients.

Abnormal expression of CDK11p58 in prostate cancer

BackgroundCDK11p58 is one of the large families of p34cdc2-related kinases whose functions are linked with cell cycle progression, tumorigenesis and apoptotic signaling. Our previous investigation demonstrated that CDK11p58 repressed androgen receptor (AR) transcriptional activity and was involved in the negative regulation of AR function.MethodsCDK11p58 expression was examined in the prostate cancer tissues and adjacent tissues by IHC and qRT-PCR. Cell apoptosis was detected by flow cytometry. The metastasis of cancer cells was evaluated by the Transwell Assay. Finally we further investigated the underlying molecular mechanisms by examining expression levels of relevant proteins using western blot analysis.ResultsWe found that both RNA and protein expression of CDK11p58 were low in prostate cancer tissues compared with its adjacent noncancerous tissues. CDK11p58 promoted the prostate cancer cell apoptosis and inhibited its metastasis in a kinase dependent way. And finally CDK11p58 could inhibit the metastasis of AR positive prostate cancer cells through inhibition of integrin β3 and MMP2.ConclusionsThese data indicate that CDK11p58 is an anti-metastasis gene product in prostate cancer.

The BMP inhibitor DAND5 in serum predicts poor survival in breast cancer

Background & Aims Breast cancer (BC) is prevalent worldwide malignant cancer. Improvements in timely and effective diagnosis and prediction are needed. As reported, secreted DAND5 is contributed to BC metastasis. We aim to assess whether DAND5 in peripheral blood serum could determine BC-specific mortality. Methods We used immunohistochemistry staining to detect DAND5 expression in our BC tissue array including 250 samples. Angiogenesis assay and xenograft mice model were used to examine the secreted DAND5 function in BC progression. Serum concentration of DAND5 was examined by ELISA in 1730 BC patients. Kaplan-Meier and adjusted Cox proportional hazards models were utilized to analyze the prognosis and survival of BC patients. Results Tissue array results showed that positive DAND5 staining cases displayed a higher likelihood of occurrence of disease events (HR=5.494; 95% CI: 1.008-2.353; P=0.048) in univariate analysis and remained the same trend in multivariate analysis (HR=2.537; 95% CI: 1.056-6.096; P=0.037). DAND5 positive patients exerted generally poor DFS (P=0.041) in the Kaplan-Meier survival analysis. Furthermore, secreted DAND5 promoted tumor growth and angiogenesis in vitro and in vivo. In addition, positive DAND5 in BC patients serum was associated with increased risk of disease events occurrence (univariate: HR=1.58; 95% CI: 1.206-2.070; P=0.001; multivariate: HR=1.4; 95% CI: 1.003-1.954; P=0.048) in univariate and multivariate survival analysis. In the Kaplan-Meier analysis, serum DAND5 positively correlated with poor DFS (P=0.001) and DDFS (P=0.002). Conclusions DAND5 was correlated with poor survival and could serve as an easily detectable serum biomarker to predict the survival of breast cancer.