scholarly journals TARBP2-Enhanced Resistance during Tamoxifen Treatment in Breast Cancer

Cancers ◽  
2019 ◽  
Vol 11 (2) ◽  
pp. 210 ◽  
Author(s):  
Ming-Yang Wang ◽  
Hsin-Yi Huang ◽  
Yao-Lung Kuo ◽  
Chiao Lo ◽  
Hung-Yu Sun ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Hormone Therapy ◽  
Cancer Cells ◽  
Breast Cancer Cells ◽  
Cancer Metastasis ◽  
Rna Binding ◽  
Tamoxifen Resistance ◽  
Breast Cancer Metastasis ◽  
Tamoxifen Treatment ◽  
Breast Cancers

Tamoxifen is the most widely used hormone therapy in estrogen receptor-positive (ER+) breast cancer, which accounts for approximately 70% of all breast cancers. Although patients who receive tamoxifen therapy benefit with respect to an improved overall prognosis, resistance and cancer recurrence still occur and remain important clinical challenges. A recent study identified TAR (HIV-1) RNA binding protein 2 (TARBP2) as an oncogene that promotes breast cancer metastasis. In this study, we showed that TARBP2 is overexpressed in hormone therapy-resistant cells and breast cancer tissues, where it enhances tamoxifen resistance. Tamoxifen-induced TARBP2 expression results in the desensitization of ER+ breast cancer cells. Mechanistically, tamoxifen post-transcriptionally stabilizes TARBP2 protein through the downregulation of Merlin, a TARBP2-interacting protein known to enhance its proteasomal degradation. Tamoxifen-induced TARBP2 further stabilizes SOX2 protein to enhance desensitization of breast cancer cells to tamoxifen, while similar to TARBP2, its induction in cancer cells was also observed in metastatic tumor cells. Our results indicate that the TARBP2-SOX2 pathway is upregulated by tamoxifen-mediated Merlin downregulation, which subsequently induces tamoxifen resistance in ER+ breast cancer.

scholarly journals Biomechanical regulation of breast cancer metastasis and progression

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Adrianne Spencer ◽  
Andrew D. Sligar ◽  
Daniel Chavarria ◽  
Jason Lee ◽  
Darshil Choksi ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Cancer Cells ◽  
Breast Cancer Cells ◽  
Cancer Metastasis ◽  
Mechanical Load ◽  
Breast Cancer Metastasis ◽  
Proliferation And Metastasis ◽  
Xenograft Models ◽  
Chemotherapeutic Treatment ◽  
Complex Signaling

AbstractPhysical activity has been consistently linked to decreased incidence of breast cancer and a substantial increase in the length of survival of patients with breast cancer. However, the understanding of how applied physical forces directly regulate breast cancer remains limited. We investigated the role of mechanical forces in altering the chemoresistance, proliferation and metastasis of breast cancer cells. We found that applied mechanical tension can dramatically alter gene expression in breast cancer cells, leading to decreased proliferation, increased resistance to chemotherapeutic treatment and enhanced adhesion to inflamed endothelial cells and collagen I under fluidic shear stress. A mechanistic analysis of the pathways involved in these effects supported a complex signaling network that included Abl1, Lck, Jak2 and PI3K to regulate pro-survival signaling and enhancement of adhesion under flow. Studies using mouse xenograft models demonstrated reduced proliferation of breast cancer cells with orthotopic implantation and increased metastasis to the skull when the cancer cells were treated with mechanical load. Using high throughput mechanobiological screens we identified pathways that could be targeted to reduce the effects of load on metastasis and found that the effects of mechanical load on bone colonization could be reduced through treatment with a PI3Kγ inhibitor.

scholarly journals Mitochondrial Malic Enzyme 2 Promotes Breast Cancer Metastasis via Stabilizing HIF-1α Under Hypoxia

2021 ◽  
Author(s):  
Duo You ◽  
Danfeng Du ◽  
Xueke Zhao ◽  
Xinmin Li ◽  
Minfeng Ying ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Cancer Cells ◽  
Cancer Patients ◽  
Breast Cancer Cells ◽  
Cancer Metastasis ◽  
Breast Cancer Metastasis ◽  
High Expression ◽  
Breast Cancer Patients ◽  
Cancer Model ◽  
Breast Cancer Model

Abstract Background: α-ketoglutarate (α-KG) is the substrate to hydoxylate collagen and hypoxia-inducible factor-1α (HIF-1α), which are important for cancer metastasis. Previous studies showed that upregulation of collagen prolyl 4-hydroxylase in breast cancer cells stabilizes HIF-1α via depleting α-KG in breast cancer cells. We propose that mitochondrial malate enzyme 2 (ME2) may also affect HIF-1α via modulating α-KG level in breast cancer cells. Methods: ME2 protein expression was evaluated by immunohistochemistry on 100 breast cancer patients and correlated with clinicopathological indicators. The effect of ME2 knockout on cancer metastasis was evaluated by an orthotopic breast cancer model. The effect of ME2 knockout or knockdown on the levels of α-KG and HIF-1α protein in breast cancer cell lines (4T1 and MDA-MB-231) was determined in vitro and in vivo.Results: The high expression of ME2 was observed in the human breast cancerous tissues compared to the matched precancerous tissues (P=0.000). The breast cancer patients with a high expression of ME2 had an inferior survival than the patients with low expression of ME2 (P=0.019). ME2 high expression in breast cancer tissues was also related with lymph node metastasis (P=0.016), pathological staging (P=0.033) and vascular cancer embolus (P=0.014). In a 4T1 orthotopic breast cancer model, ME2 knockout significantly inhibited lung metastasis. In the tumors formed by ME2 knockout 4T1 cells, α-KG level significantly increased, collagen hydroxylation level did not change significantly, but HIF-1α protein level significantly decreased, in comparison to control. In cell culture, ME2 knockout or knockdown cells demonstrated a significantly higher α-KG level but significantly lower HIF-1α protein level than control cells under hypoxia. Exogenous malate and α-KG exerted similar effect on HIF-1α in breast cancer cells to ME2 knockout or knockdown. Treatment with malate significantly decreased 4T1 breast cancer lung metastasis. ME2 expression was associated with HIF-1α level in human breast cancer samples (P=0.027).Conclusion: We provide evidence that upregulation of ME2 is associated with a poor prognosis of breast cancer patients and propose a mechanistic understanding of a link between ME2 and breast cancer metastasis.

BRMS1L inhibits bone metastasis of breast cancer cells through epigenetic silence of CXCR4.

2021 ◽  
Vol 39 (15_suppl) ◽  
pp. e13002-e13002
Author(s):  
Yinghuan Cen ◽  
Chang Gong ◽  
Jun Li ◽  
Gehao Liang ◽  
Zihao Liu ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Bone Metastasis ◽  
Cancer Cells ◽  
Breast Cancer Cells ◽  
Cancer Metastasis ◽  
Breast Cancer Metastasis ◽  
Breast Cancer Cell Lines ◽  
Breast Cancer Patients ◽  
Qrt Pcr ◽  
Metastatic Sites

e13002 Background: We previously demonstrated that BRMS1L (breast cancer metastasis suppressor 1 like) suppresses breast cancer metastasis through HDAC1 recruitment and histone H3K9 deacetylation at the promoter of FZD10, a receptor for Wnt signaling. It is still unclear whether BRMS1L regulates organ-specific metastases, such as bone metastasis, the most prevalent metastatic site of breast cancer. Methods: Examination of the expression of BRMS1L in primary tumors, bone metastatic and other metastatic tissues from breast cancer patients was implemented using qRT-PCR and immunohistochemistry staining. To investigate the mechanism by which BRMS1L drives breast cancer bone metastasis, we tested the mRNA expression by qRT-PCR of a set of potential bone related genes (BRGs) based on PubMed database in MDA-MB-231 cells over expressing BRMS1L and MCF-7 cells knocking-down BRMS1L, and detected the expression of CXCR4 in these established cells by western blot. Transwell assays were performed to assess the migration abilities of breast cancer cells towards osteoblasts. ChIP (Chromatin Immuno-Precipitation) were employed to test the interaction between BRMS1L and CXCR4. Results: At both mRNA and protein levels, the expression of BRMS1L was significantly lower in bone metastatic sites than that in primary cancer tissues and other metastatic sites of breast cancer patients. CXCR4 was screened out in a set of BRGs and negatively correlated with the expression of BRMS1L in breast cancer cell lines. BRMS1L inhibited the migration of breast cancer cells towards osteoblasts through CXCL12/CXCR4 axis. In the presence of TSA treatment, breast cancer cell lines showed an increased expression of CXCR4 in a TSA concentration-dependent manner. In addition, ChIP assays verified that BRMS1L directly bound to the promoter region of CXCR4 and inhibited its transcription through promoter histone deacetylation. Conclusions: BRMS1L mediates the migration abilities of breast cancer cells to bone microenvironment via targeting CXCR4 and contributes to bone metastasis of breast cancer cells. Thus, BRMS1L may be a potential biomarker for predicting bone metastasis in breast cancer.

scholarly journals Poly-ADP-Ribosylation of Estrogen Receptor-Alpha by PARP1 Mediates Antiestrogen Resistance in Human Breast Cancer Cells

Cancers ◽  
2019 ◽  
Vol 11 (1) ◽  
pp. 43 ◽  
Author(s):  
Nicholas Pulliam ◽  
Jessica Tang ◽  
Weini Wang ◽  
Fang Fang ◽  
Riddhi Sood ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Oxidative Stress ◽  
Estrogen Receptor ◽  
Cancer Cells ◽  
Breast Cancer Cells ◽  
Target Genes ◽  
Tamoxifen Resistance ◽  
Tamoxifen Treatment ◽  
Dependent Manner ◽  
Tamoxifen Resistant

Therapeutic targeting of estrogen receptor-α (ERα) by the anti-estrogen tamoxifen is standard of care for premenopausal breast cancer patients and remains a key component of treatment strategies for postmenopausal patients. While tamoxifen significantly increases overall survival, tamoxifen resistance remains a major limitation despite continued expression of ERα in resistant tumors. Previous reports have described increased oxidative stress in tamoxifen resistant versus sensitive breast cancer and a role for PARP1 in mediating oxidative damage repair. We hypothesized that PARP1 activity mediated tamoxifen resistance in ERα-positive breast cancer and that combining the antiestrogen tamoxifen with a PARP1 inhibitor (PARPi) would sensitize tamoxifen resistant cells to tamoxifen therapy. In tamoxifen-resistant vs. -sensitive breast cancer cells, oxidative stress and PARP1 overexpression were increased. Furthermore, differential PARylation of ERα was observed in tamoxifen-resistant versus -sensitive cells, and ERα PARylation was increased by tamoxifen treatment. Loss of ERα PARylation following treatment with a PARP inhibitor (talazoparib) augmented tamoxifen sensitivity and decreased localization of both ERα and PARP1 to ERα-target genes. Co-administration of talazoparib plus tamoxifen increased DNA damage accumulation and decreased cell survival in a dose-dependent manner. The ability of PARPi to overcome tamoxifen resistance was dependent on ERα, as lack of ERα-mediated estrogen signaling expression and showed no response to tamoxifen-PARPi treatment. These results correlate ERα PARylation with tamoxifen resistance and indicate a novel mechanism-based approach to overcome tamoxifen resistance in ER+ breast cancer.

scholarly journals Inhibiting PAD2 enhances the anti-tumor effect of docetaxel in tamoxifen-resistant breast cancer cells

2019 ◽  
Vol 38 (1) ◽  
Author(s):  
Fujun Li ◽  
Lixia Miao ◽  
Teng Xue ◽  
Hao Qin ◽  
Santanu Mondal ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Cancer Cells ◽  
Combination Treatment ◽  
Breast Cancer Cells ◽  
Tamoxifen Resistance ◽  
Nuclear Accumulation ◽  
Breast Cancers ◽  
Inhibition Of Proliferation ◽  
Tamoxifen Resistant

Abstract Background Tamoxifen resistance presents a huge clinical challenge for breast cancer patients. An understanding of the mechanisms of tamoxifen resistance can guide development of efficient therapies to prevent drug resistance. Methods We first tested whether peptidylarginine deiminase 2 (PAD2) may be involved in tamoxifen-resistance in breast cancer cells. The effect of depleting or inhibiting PAD2 in tamoxifen-resistant MCF-7 (MCF7/TamR) cells was evaluated both in vitro and in vivo. We then investigated the potential of Cl-amidine, a PAD inhibitor, to be used in combination with tamoxifen or docetaxel, and further explored the mechanism of the synergistic and effective drug regimen of PADs inhibitor and docetaxel on tamoxifen-resistant breast cancer cells. Results We report that PAD2 is dramatically upregulated in tamoxifen-resistant breast cancer. Depletion of PAD2 in MCF7/TamR cells facilitated the sensitivity of MCF7/TamR cells to tamoxifen. Moreover, miRNA-125b-5p negatively regulated PAD2 expression in MCF7/TamR cells, therefore overexpression of miR-125b-5p also increased the cell sensitivity to tamoxifen. Furthermore, inhibiting PAD2 with Cl-amidine not only partially restored the sensitivity of MCF7/TamR cells to tamoxifen, but also more efficiently enhanced the efficacy of docetaxel on MCF7/TamR cells with lower doses of Cl-amidine and docetaxel both in vivo and in vivo. We then showed that combination treatment with Cl-amidine and docetaxel enhanced p53 nuclear accumulation, which synergistically induced cell cycle arrest and apoptosis. Meanwhile, p53 activation in the combination treatment also accelerated autophagy processes by synergistically decreasing the activation of Akt/mTOR signaling, thus enhancing the inhibition of proliferation. Conclusion Our results suggest that PAD2 functions as an important new biomarker for tamoxifen-resistant breast cancers and that inhibiting PAD2 combined with docetaxel may offer a new approach to treatment of tamoxifen-resistant breast cancers.

miR-214 inhibits epithelial–mesenchymal transition of breast cancer cells via downregulation of RNF8

2019 ◽  
Vol 51 (8) ◽  
pp. 791-798 ◽  
Author(s):  
Lu Min ◽  
Chuanyang Liu ◽  
Jingyu Kuang ◽  
Xiaomin Wu ◽  
Lingyun Zhu
Keyword(s):  
Breast Cancer ◽  
Cancer Cells ◽  
Breast Cancer Cells ◽  
Cancer Metastasis ◽  
Epithelial Mesenchymal Transition ◽  
Breast Cancer Metastasis ◽  
Breast Cancer Patients ◽  
Mesenchymal Transition ◽  
Proliferation And Invasion

Abstract MicroRNAs (miRNAs) are a class of endogenous noncoding genes that regulate gene expression at the posttranscriptional level. In recent decades, miRNAs have been reported to play important roles in tumor growth and metastasis, while some reported functions of a specific miRNA in tumorigenesis are contradictory. In this study, we reevaluated the role of miR-214, which has been reported to serve as an oncogene or anti-oncogene in breast cancer metastasis. We found that miR-214 inhibited breast cancer via targeting RNF8, a newly identified regulator that could promote epithelial–mesenchymal transition (EMT). Specifically, the survival rate of breast cancer patients was positively correlated with miR-214 levels and negatively correlated with RNF8 expression. The overexpression of miR-214 inhibited cell proliferation and invasion of breast cancer, while suppression of miR-214 by chemically modified antagomir enhanced the proliferation and invasion of breast cancer cells. Furthermore, miR-214 could modulate the EMT process via downregulating RNF8. To our knowledge, this is the first report that reveals the role of the miR-214–RNF8 axis in EMT, and our results demonstrate a novel mechanism for miR-214 acting as a tumor suppressor through the regulation of EMT.

scholarly journals LAMP3 is involved in tamoxifen resistance in breast cancer cells through the modulation of autophagy

2014 ◽  
Vol 21 (1) ◽  
pp. 101-112 ◽  
Author(s):  
Anika Nagelkerke ◽  
Anieta M Sieuwerts ◽  
Johan Bussink ◽  
Fred C G J Sweep ◽  
Maxime P Look ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Mrna Expression ◽  
Cancer Cells ◽  
Breast Cancer Cells ◽  
Tamoxifen Resistance ◽  
Tamoxifen Treatment ◽  
Breast Cancer Patients ◽  
Mcf7 Cells ◽  
First Line ◽  
Tamoxifen Resistant

Lysosome-associated membrane protein 3 (LAMP3) is a member of the LAMP-family of proteins, which are involved in the process of autophagy. Autophagy is induced by tamoxifen in breast cancer cells and may contribute to tamoxifen resistance. In this study, the significance of LAMP3 for tamoxifen resistance in breast cancer was examined. The methods employed included use of clonogenic assays to assess the survival of MCF7 breast cancer cells with LAMP3 knockdown after tamoxifen treatment and of quantitative real-time PCR of LAMP3 to evaluate its predictive value for first-line tamoxifen treatment in patients with advanced breast cancer. Results show that tamoxifen treatment of MCF7 cells induced LAMP3 mRNA expression. LAMP3 knockdown in these cells increased tamoxifen sensitivity. Evaluation of expression of the autophagy markers, LC3B and p62, after LAMP3 knockdown showed increased expression levels, indicating that cells with LAMP3 knockdown have a suppressed ability to complete the autophagic process. In addition, knockdown of autophagy-associated genes resulted in sensitization to tamoxifen. Next, tamoxifen-resistant MCF7 cells were cultured. These cells had a sevenfold higher LAMP3 mRNA expression, showed elevated basal autophagy levels, and could be significantly resensitized to tamoxifen by LAMP3 knockdown. In patients treated with first-line tamoxifen for advanced disease (n=304), high LAMP3 mRNA expression was associated with shorter progression-free survival (P=0.003) and shorter post-relapse overall survival (P=0.040), also in multivariate analysis. Together, these results indicate that LAMP3 contributes to tamoxifen resistance in breast cancer. Tamoxifen-resistant cells are resensitized to tamoxifen by the knockdown of LAMP3. Therefore, LAMP3 may be clinically relevant to countering tamoxifen resistance in breast cancer patients.

scholarly journals NUPR1 Promotes the Proliferation and Migration of Breast Cancer Cells by Activating TFE3 Transcription to Induce Autophagy

2021 ◽  
Author(s):  
Heng Xiao ◽  
Jing Long ◽  
Xiang Chen ◽  
Mi-Duo Tan
Keyword(s):  
Breast Cancer ◽  
Western Blot ◽  
Cancer Cells ◽  
Breast Cancer Cells ◽  
Cancer Metastasis ◽  
Translocation Factor ◽  
Breast Cancer Metastasis ◽  
Migration And Invasion ◽  
Related Proteins

Abstract Background: Breast cancer is a commonplace carcinoma in females. Recurrence and metastasis are the main problems affecting the survival rate of patients. The fundamental reason is the lack of understanding of the mechanism of breast cancer metastasis. This study aims to deliberate on the efficaciousness of Nuclear protein 1 (NUPR1)-mediated autophagy on breast cancer metastasis.Methods: The proliferation, migration and invasion ability of breast cancer cells were appraised by CCK-8, wound healing, and colony formation, as well as transwell assay. The relationship between NUPR1 and Translocation factor E3 (TFE3) was appraised by qPCR, western blot and ChIP. Migration-invasion-related proteins and autophagy-related proteins were appraised by western blot. The effects of NUPR1 on malignancy formation and metastasis were studied in vivo.Results: NUPR1 was upregulated in breast cancer cells and tissues. NUPR1 knockdown restrained the proliferation, migration and invasion of ZR-75-30 cells. Moreover, NUPR1 knockdown restrained malignancy formation and metastasis in vivo. Mechanically, NUPR1 promoted autophagy through activation of TFE3 transcription, thereby regulating the process of breast cancer metastasis.Conclusion: This paper elucidates the molecular mechanism of NUPR1 promoting breast cancer metastasis by activating autophagy through TFE3 signaling pathway, which provided biological basis for intervention of blocking distant metastasis.

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