scholarly journals Expression of MALAT1 Promotes Trastuzumab Resistance in HER2 Overexpressing Breast Cancers

Cancers ◽  
2020 ◽  
Vol 12 (7) ◽  
pp. 1918
Author(s):  
Yanyuan Wu ◽  
Marianna Sarkissyan ◽  
Ochanya Ogah ◽  
Juri Kim ◽  
Jaydutt V. Vadgama

Background: Metastasis-associated lung adenocarcinoma transcript 1 (MALAT1) is associated with cancer progression. Our study examined the role of MALAT1 in breast cancer and the mechanisms involved in the regulation of MALAT1. Methods: In vitro cell and in vivo animal models were used to examine the role of MALAT1 in breast cancer. The interaction of FOXO1 (Forkhead Box O1) at the promoter region of MALAT1 was investigated by chromatin immunoprecipitation (ChIP) assay. Results: The data shows an elevated expression of MALAT1 in breast cancer tissues and cells compared to non-cancer tissues and cells. The highest level of MALAT1 was observed in metastatic triple-negative breast cancer and trastuzumab-resistant HER2 (human epidermal growth factor receptor 2) overexpressing (HER2+) cells. Knockdown of MALAT1 in trastuzumab-resistant HER2+ cells reversed epithelial to mesenchymal transition-like phenotype and cell invasiveness. It improved the sensitivity of the cell’s response to trastuzumab. Furthermore, activation of Akt by phosphorylation was associated with the upregulation of MALAT1. The transcription factor FOXO1 regulates the expression of MALAT1 via the PI3/Akt pathway. Conclusions: We show that MALAT1 contributes to HER2+ cell resistance to trastuzumab. Targeting the PI3/Akt pathway and stabilizing FOXO1 translocation could inhibit the upregulation of MALAT1.

2021 ◽  
Vol 11 ◽  
Author(s):  
Ying Zhang ◽  
Yi Sun ◽  
Lin Ding ◽  
Wenjing Shi ◽  
Keshuo Ding ◽  
...  

Breast cancer remains the leading cause of female cancer-related mortalities worldwide. Long non-coding RNAs (LncRNAs) have been increasingly reported to play pivotal roles in tumorigenesis and cancer progression. Herein, we focused on LINC00467, which has never been studied in breast cancer. Silence of LINC00467 suppressed proliferation, migration, invasion and epithelial-to-mesenchymal transition (EMT) of breast cancer cells in vitro, whereas forced expression of LINC00467 exhibited the opposite effects. Furthermore, we demonstrated overexpression of LINC00467 promoted tumor growth, while knockdown of LINC00467 inhibited pulmonary metastasis in vivo. Mechanistically, LINC00467 down-regulated miR-138-5p by acting as a miRNA “sponge”. Besides, LINC00467 also up-regulated the protein level of lin-28 homolog B (LIN28B) via a direct interaction. A higher expression level of LINC00467 was observed in breast cancer tissues as compared to the adjacent normal counterparts and elevated LINC00467 predicted poor overall survival. Our findings suggest LINC00467 promotes progression of breast cancer through interacting with miR-138-5p and LIN28B directly. LINC00467 may serve as a potential candidate for the diagnosis and treatment of breast cancer.


Author(s):  
Jun-Xian Du ◽  
Yi-Hong Luo ◽  
Si-Jia Zhang ◽  
Biao Wang ◽  
Cong Chen ◽  
...  

Abstract Background Intensive evidence has highlighted the effect of aberrant alternative splicing (AS) events on cancer progression when triggered by dysregulation of the SR protein family. Nonetheless, the underlying mechanism in breast cancer (BRCA) remains elusive. Here we sought to explore the molecular function of SRSF1 and identify the key AS events regulated by SRSF1 in BRCA. Methods We conducted a comprehensive analysis of the expression and clinical correlation of SRSF1 in BRCA based on the TCGA dataset, Metabric database and clinical tissue samples. Functional analysis of SRSF1 in BRCA was conducted in vitro and in vivo. SRSF1-mediated AS events and their binding motifs were identified by RNA-seq, RNA immunoprecipitation-PCR (RIP-PCR) and in vivo crosslinking followed by immunoprecipitation (CLIP), which was further validated by the minigene reporter assay. PTPMT1 exon 3 (E3) AS was identified to partially mediate the oncogenic role of SRSF1 by the P-AKT/C-MYC axis. Finally, the expression and clinical significance of these AS events were validated in clinical samples and using the TCGA database. Results SRSF1 expression was consistently upregulated in BRCA samples, positively associated with tumor grade and the Ki-67 index, and correlated with poor prognosis in a hormone receptor-positive (HR+) cohort, which facilitated proliferation, cell migration and inhibited apoptosis in vitro and in vivo. We identified SRSF1-mediated AS events and discovered the SRSF1 binding motif in the regulation of splice switching of PTPMT1. Furthermore, PTPMT1 splice switching was regulated by SRSF1 by binding directly to its motif in E3 which partially mediated the oncogenic role of SRSF1 by the AKT/C-MYC axis. Additionally, PTPMT1 splice switching was validated in tissue samples of BRCA patients and using the TCGA database. The high-risk group, identified by AS of PTPMT1 and expression of SRSF1, possessed poorer prognosis in the stage I/II TCGA BRCA cohort. Conclusions SRSF1 exerts oncogenic roles in BRCA partially by regulating the AS of PTPMT1, which could be a therapeutic target candidate in BRCA and a prognostic factor in HR+ BRCA patient.


2021 ◽  
Vol 108 (Supplement_1) ◽  
Author(s):  
C Zabkiewicz ◽  
L Ye ◽  
R Hargest

Abstract Introduction HER2 over-expression denotes poor prognosis in breast cancers.Bone morphogenetic protein(BMP) signalling is known to interact with EGF signalling, co-regulating breast cancer progression.BMP antagonist Gremlin-1 may influence breast cancer disease progression, but this remains unexplored in HER2 positive breast cancers. Method GREM1 and HER2 expression, and clinical outcomes were examined in clinical cohorts.GREM1 overexpression or pEF control plasmid were transduced into BT474 HER2+breast cancer cells. In vitro function tests using BT474 pEF and BT474GREM1cells include 2D/3D growth, migration, and expression of epithelial to mesenchymal transition(EMT)markers. Signalling cascades were examined in BT474 treated with RhGremlin-1. In vivo, BALB/c nude mice underwent either mammary injection or intra-cardiac injection of BT474pEF or BT474GREM1 cells and disease burden assessed. Result GREM1 expression correlates with HER2 in breast tumours(p=0.03) and is higher in metastatic HER2 positive cancers (p = 0.04). HER2 positive patients with high GREM1 have poor survival(p = 0.0002). BT474GREM1cells have up-regulated markers of EMT compared to control. BT474 RhGremlin-1 treated cells have active AKT pathway signalling, independent of BMP signalling. In vitro,  BT474GREM1cells significantly proliferate and migrate compared to control(p<0.05 and p < 0.001).This is confirmed in vivo,  BT474GREM1 mice grew significantly larger mammary tumours(p<0.05) and had more PETCT metastatic hotspots. Conclusion Gremlin-1 is correlated with poor outcomes in HER2 patients and promotes breast cancer cellular growth, migration and metastasis.Gremlin-1 is a novel area of research with potential as a prognostic biomarker and therapeutic target for personalised, effective, breast cancer outcomes. Take-home message BMP antagonists are gaining interest for their potential in breast cancer prognosis and therapeutics.This novel area of research shows BMP antagonist Gremlin-1 is of importance in HER2 positive breast cancers. DRAGONS DEN


2021 ◽  
Vol 20 (1) ◽  
Author(s):  
Ya Fan ◽  
Jia Wang ◽  
Wen Jin ◽  
Yifei Sun ◽  
Yuemei Xu ◽  
...  

Abstract Background E3 ubiquitin ligase HRD1 (HMG-CoA reductase degradation protein 1, alias synoviolin with SYVN1 as the official gene symbol) was found downregulated and acting as a tumor suppressor in breast cancer, while the exact expression profile of HRD1 in different breast cancer subtypes remains unknown. Recent studies characterized circular RNAs (circRNAs) playing an regulatory role as miRNA sponge in tumor progression, presenting a new viewpoint for the post-transcriptional regulation of cancer-related genes. Methods Examination of the expression of HRD1 protein and mRNA was implemented using public microarray/RNA-sequencing datasets and breast cancer tissues/cell lines. Based on public RNA-sequencing results, online databases and enrichment/clustering analyses were used to predict the specific combinations of circRNA/miRNA that potentially govern HRD1 expression. Gain-of-function and rescue experiments in vitro and in vivo were executed to evaluate the suppressive effects of circNR3C2 on breast cancer progression through HRD1-mediated proteasomal degradation of Vimentin, which was identified using immunoblotting, immunoprecipitation, and in vitro ubiquitination assays. Results HRD1 is significantly underexpressed in triple-negative breast cancer (TNBC) against other subtypes and has an inverse correlation with Vimentin, inhibiting the proliferation, migration, invasion and EMT (epithelial-mesenchymal transition) process of breast cancer cells via inducing polyubiquitination-mediated proteasomal degradation of Vimentin. CircNR3C2 (hsa_circ_0071127) is also remarkably downregulated in TNBC, negatively correlated with the distant metastasis and lethality of invasive breast carcinoma. Overexpressing circNR3C2 in vitro and in vivo leads to a crucial enhancement of the tumor-suppressive effects of HRD1 through sponging miR-513a-3p. Conclusions Collectively, we elucidated a bona fide circNR3C2/miR-513a-3p/HRD1/Vimentin axis that negatively regulates the metastasis of TNBC, suggesting that circNR3C2 and HRD1 can act as potential prognostic biomarkers. Our study may facilitate the development of therapeutic agents targeting circNR3C2 and HRD1 for patients with aggressive breast cancer.


2021 ◽  
Author(s):  
xingang wang ◽  
YAN ZHENG ◽  
YU WANG

Abstract Background and AimsPseudopodium-enriched atypical kinase 1 (PEAK1) has reported to be upregulated in human malignancies and related with poor prognosis. Enhanced PEAK1 expression facilitates tumor cell survival, invasion, metastasis and chemoresistance. However, the role of PEAK1 in breast cancer is not clear. Here, we investigated the PEAK1 expression in breast cancer and analyzed its relation with clinicopathological status and chemotherapy resistance to the neoadjuvant chemotherapy (NAC). We also investigated the role of PEAK1 on breast cancer cells in vitro and in vivo. MethodsImmunohistochemistry (IHC) was performed in 112 surgical resected breast cancer tissues. The associations between clinicopathological status, multi-drug resistance and PEAK1 expression were determined. Effect of PEAK1 overexpression or down-expression on proliferation, colony formation, invasion, migration, metastasis and Doxorubicin sensitivity in the MCF-7 cells in vitro and in vivo was detected. ResultsPEAK1 was overexpressed in breast cancer tissues and NAC -resistant breast cancer tissues. High PEAK1 expression was related with tumor size, high tumor grade, T stage, LN metastasis, recurrence, Ki-67 expression, Her-2 expression and multi-drug resistance. Targeting PEAK1 inhibited cell growth, invasion, metastasis and reversed chemoresistance to Doxorubicin in breast cancer cells in vitro and in vivo. ConclusionHigh PEAK1 expression was associated with invasion, metastasis and chemoresistance of breast cancers. Furthermore, targeting PEAK1 could inhibit cell growth and metastasis, and reverse chemoresistance in breast cancer cells, which provides an effective treatment strategies for breast cancer.


2016 ◽  
Vol 0 (0) ◽  
Author(s):  
Min Yang ◽  
Nan Jiang ◽  
Qi-wei Cao ◽  
Qing Sun

Abstract Gastric cancer is the most common digestive malignant tumor worldwild. EDD1 was reported to be frequently amplified in several tumors and played an important role in the tumorigenesis process. However, the biological role and potential mechanism of EDD1 in gastric cancer remains poorly understood. In this study, we are aim to investigate the effect of EDD1 on gastric cancer progression and to explore the underlying mechanism. The results showed the significant up-regulation of EDD1 in -gastric cancer cell tissues and lines. The expression level of EDD1 was also positively associated with advanced clinical stages and predicted poor overall patient survival and poor disease-free patient survival. Besides, EDD1 knockdown markedly inhibited cell viability, colony formation, and suppressed tumor growth. Opposite results were obtained in gastric cancer cells with EDD1 overexpression. EDD1 knockdown was also found to induce gastric cancer cells apoptosis. Further investigation indicated that the oncogenic role of EDD1 in regulating gastric cancer cells growth and apoptosis was related to its PABC domain and directly through targeting miR-22, which was significantly down-regulated in gastric cancer tissues. Totally, our study suggests that EDD1 plays an oncogenic role in gastric cancer and may be a potential therapeutic target for gastric cancer.


2021 ◽  
Vol 41 (1) ◽  
Author(s):  
Cui-Cui Zhao ◽  
Jing Chen ◽  
Li-Ying Zhang ◽  
Hong Liu ◽  
Chuan-Gui Zhang ◽  
...  

Abstract Triple negative breast cancer (TNBC) is a more common type of breast cancer with high distant metastasis and poor prognosis. The potential role of lamins in cancer progression has been widely revealed. However, the function of lamin B2 (LMNB2) in TNBC progression is still unclear. The present study aimed to investigate the role of LMNB2 in TNBC. The cancer genome atlas (TCGA) database analysis and immunohistochemistry (IHC) were performed to examine LMNB2 expression levels. LMNB2 short hairpin RNA plasmid or lentivirus was used to deplete the expression of LMNB2 in human TNBC cell lines including MDA-MB-468 and MDA-MB-231. Alterations in cell proliferation and apoptosis in vitro and the nude mouse tumorigenicity assay in vivo were subsequently analyzed. The human TNBC tissues shown high expression of LMNB2 according to the bioinformation analysis and IHC assays. LMNB2 expression was correlated with the clinical pathological features of TNBC patients, including pTNM stage and lymph node metastasis. Through in vitro and in vivo assays, we confirmed LMNB2 depletion suppressed the proliferation and induced the apoptosis of TNBC cells, and inhibited tumor growth of TNBC cells in mice, with the decrease in Ki67 expression or the increase in caspase-3 expression. In conclusion, LMNB2 may promote TNBC progression and could serve as a potential therapeutic target for TNBC treatment.


Epigenomics ◽  
2019 ◽  
Vol 11 (10) ◽  
pp. 1163-1176 ◽  
Author(s):  
Yanan Kong ◽  
Lu Yang ◽  
Weidong Wei ◽  
Ning Lyu ◽  
Yutian Zou ◽  
...  

Aim: To investigate the role of circRNAs in triple-negative breast cancer (TNBC) and the underlying mechanisms. Materials & methods: We performed circRNA microarrays to explore the expression profiles of TNBC cell lines. Experiments in vitro and in vivo were conducted to explore the effects of circPLK1 on tumor proliferation and metastasis as well as the interaction between circPLK1, miR-296-5p and PLK1 in TNBC. Results & conclusion: CircPLK1 was significantly upregulated in TNBC and associated with poor survivals. CircPLK1 knockdown inhibited cell growth and invasion in vitro as well as tumor occurrence and metastasis in vivo. CircPLK1-miR-296-5p- PLK1 axis regulates tumor progression by ceRNA mechanism in TNBC, indicating that circPLK1 may serve as a prognostic factor and novel therapeutic target for TNBC.


2021 ◽  
Vol 7 (1) ◽  
Author(s):  
Yixiang Huang ◽  
Wenfang Zheng ◽  
Changle Ji ◽  
Xuehui Wang ◽  
Yunhe Yu ◽  
...  

AbstractBreast cancer (BC) is one of the most fatal diseases among women all over the world. Non-coding RNAs including circular RNAs (circRNAs) have been reported to be involved in different aspects during tumorigenesis and progression. In this study, we aimed to explore the biological functions and underlying mechanism of circRPPH1 in BC. Candidate circRNAs were screened in dataset GSE101123 from Gene Expression Omnibus (GEO) database and a differentially expressed circRNA, circRPPH1, was discovered in BC. CircRPPH1 expression was higher in the cancerous tissue compared to paired adjacent tissue. Further in vitro and in vivo experiments indicated that circRPPH1 acted as an oncogene in BC. In addition, circRPPH1 was mainly localized in cytoplasm and played the role of miR-512-5p sponge. By sequestering miR-512-5p from the 3′-UTR of STAT1, circRPPH1 inhibited the suppressive role of miR-512-5p, stabilized STAT1 mRNA in BC and finally affected BC progression. In conclusion, these findings indicated that circRPPH1 acted as an oncogene and regulated BC progression via circRPPH1-miR-512-5p-STAT1 axis, which might provide a potential therapeutic target for BC treatment.


2021 ◽  
Vol 65 (1) ◽  
Author(s):  
Chuanchao Wei ◽  
Jiayue Wu ◽  
Weiyan Liu ◽  
Jingfeng Lu ◽  
Hongchang Li ◽  
...  

Proteins in the tripartite motif-containing protein (TRIM) family participates in carcinogenesis. However, little attention was focused on the role of TRIM6 on development of breast cancer. Expression level of TRIM6 was found to be markedly enhanced in breast cancer cells and tissues. Functional assays demonstrated that overexpression of TRIM6 promoted breast cancer progression through increase of YAP1 (Yes-associated Protein 1), while knockdown of TRIM6 suppressed in vitro breast cancer progression and in vivo tumor growth through decrease of YAP1. Co-Immunoprecipitation (co-IP) showed that TRIM6 interacted with STUB1 (stress induced phosphoprotein 1 homology and U-box containing protein 1). TRIM6 promoted ubiquitination-mediated degradation of STUB1 to promote YAP1 signaling. Overexpression of STUB1 attenuated TRIM6-induced promotion of breast cancer growth. In conclusion, TRIM6 contributed to breast cancer progression through ubiquitination-dependent proteasomal degradation of STUB1 and provocation of YAP1 pathway, providing potential therapeutic target for breast cancer.


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