scholarly journals Cloning and expression of a new HOXC6 transcript encoding a repressing protein

1996 ◽  
Vol 319 (1) ◽  
pp. 91-97 ◽  
Author(s):  
Alain CHARIOT ◽  
Vincent CASTRONOVO ◽  
Phuonc LE ◽  
Claudette GILLET ◽  
Mark E. SOBEL ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Cancer Cells ◽  
Breast Cancer Cells ◽  
Target Genes ◽  
Hox Genes ◽  
Cloning And Expression ◽  
Cell Phenotype ◽  
Gene Products ◽  
Encode Gene ◽  
Binding Sequence

Homeodomain-containing proteins are transcription factors that regulate the co-ordinated expression of multiple genes involved in development, differentiation and malignant transformation. In an attempt to characterize expressed homeobox (HOX) genes in breast cancer cells, we cloned two distinct HOXC6 transcripts from an MCF7 cDNA library. Interestingly, one of them represents a new HOXC6 mRNA encoding a homeodomain-containing protein harbouring a unique N-terminal sequence. Moreover we demonstrate that this HOXC6 transcript is less abundant in human breast cancer cells than in non-tumorigenic cell lines, is detected in breast carcinomas and adjacent tissues and is expressed in a variety of human tumours. In addition, transient co-transfection experiments illustrated that both HOXC6 transcripts encode gene products that repress transcription from a HOX binding sequence in MDA-MB231 cells and co-operate with other HOX gene products such as HOXB7 on their target genes. Taken together, our results suggest that HOXC6 proteins might contribute to the breast cell phenotype through co-operative interactions with other HOX-derived proteins and repression of their target genes.

scholarly journals Nuclear ErbB2 represses DEPTOR transcription to inhibit autophagy in breast cancer cells

2021 ◽  
Vol 12 (4) ◽  
Author(s):  
Yanli Bi ◽  
Longyuan Gong ◽  
Pengyuan Liu ◽  
Xiufang Xiong ◽  
Yongchao Zhao
Keyword(s):  
Breast Cancer ◽  
Cancer Cells ◽  
Transcriptional Repression ◽  
Breast Cancer Cells ◽  
Kinase Activity ◽  
Nuclear Translocation ◽  
Extracellular Signals ◽  
Consensus Binding Sequence ◽  
Binding Sequence

AbstractErbB2, a classical receptor tyrosine kinase, is frequently overexpressed in breast cancer cells. Although the role of ErbB2 in the transmission of extracellular signals to intracellular matrix has been widely studied, the functions of nuclear ErbB2 remain largely elusive. Here, we report a novel function of nuclear ErbB2 in repressing the transcription of DEPTOR, a direct inhibitor of mTOR. Nuclear ErbB2 directly binds to the consensus binding sequence in the DEPTOR promoter to repress its transcription. The kinase activity of ErbB2 is required for its nuclear translocation and transcriptional repression of DEPTOR. Moreover, the repressed DEPTOR by nuclear ErbB2 inhibits the induction of autophagy by activating mTORC1. Thus, our study reveals a novel mechanism for autophagy regulation by functional ErbB2, which translocates to the nucleus and acts as a transcriptional regulator to suppress DEPTOR transcription, leading to activation of the PI3K/AKT/mTOR pathway to inhibit autophagy.

scholarly journals Identification of target genes in breast cancer cells directly regulated by the SRC-3/AIB1 coactivator

2005 ◽  
Vol 102 (5) ◽  
pp. 1339-1344 ◽  
Author(s):  
P. Labhart ◽  
S. Karmakar ◽  
E. M. Salicru ◽  
B. S. Egan ◽  
V. Alexiadis ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Cancer Cells ◽  
Breast Cancer Cells ◽  
Target Genes

scholarly journals Tumor-suppressor function of Beclin 1 in breast cancer cells requires E-cadherin

2021 ◽  
Vol 118 (5) ◽  
pp. e2020478118
Author(s):  
Tobias Wijshake ◽  
Zhongju Zou ◽  
Beibei Chen ◽  
Lin Zhong ◽  
Guanghua Xiao ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Tumor Suppressor ◽  
Cancer Cells ◽  
Breast Cancer Cells ◽  
Target Genes ◽  
Cellular Proliferation ◽  
Beclin 1 ◽  
Beta Catenin ◽  
A Genome ◽  
E Cadherin

Beclin 1, an autophagy and haploinsufficient tumor-suppressor protein, is frequently monoallelically deleted in breast and ovarian cancers. However, the precise mechanisms by which Beclin 1 inhibits tumor growth remain largely unknown. To address this question, we performed a genome-wide CRISPR/Cas9 screen in MCF7 breast cancer cells to identify genes whose loss of function reverse Beclin 1-dependent inhibition of cellular proliferation. Small guide RNAs targeting CDH1 and CTNNA1, tumor-suppressor genes that encode cadherin/catenin complex members E-cadherin and alpha-catenin, respectively, were highly enriched in the screen. CRISPR/Cas9-mediated knockout of CDH1 or CTNNA1 reversed Beclin 1-dependent suppression of breast cancer cell proliferation and anchorage-independent growth. Moreover, deletion of CDH1 or CTNNA1 inhibited the tumor-suppressor effects of Beclin 1 in breast cancer xenografts. Enforced Beclin 1 expression in MCF7 cells and tumor xenografts increased cell surface localization of E-cadherin and decreased expression of mesenchymal markers and beta-catenin/Wnt target genes. Furthermore, CRISPR/Cas9-mediated knockout of BECN1 and the autophagy class III phosphatidylinositol kinase complex 2 (PI3KC3-C2) gene, UVRAG, but not PI3KC3-C1–specific ATG14 or other autophagy genes ATG13, ATG5, or ATG7, resulted in decreased E-cadherin plasma membrane and increased cytoplasmic E-cadherin localization. Taken together, these data reveal previously unrecognized cooperation between Beclin 1 and E-cadherin–mediated tumor suppression in breast cancer cells.

Calcineurin regulates the stability and activity of estrogen receptor α

2021 ◽  
Vol 118 (44) ◽  
pp. e2114258118
Author(s):  
Takahiro Masaki ◽  
Makoto Habara ◽  
Yuki Sato ◽  
Takahiro Goshima ◽  
Keisuke Maeda ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Estrogen Receptor ◽  
Cancer Cells ◽  
Cancer Progression ◽  
Breast Cancer Cells ◽  
Molecular Mechanisms ◽  
Target Genes ◽  
Estrogen Receptor Α ◽  
The Stability ◽  
Positive Breast Cancer

Estrogen receptor α (ER-α) mediates estrogen-dependent cancer progression and is expressed in most breast cancer cells. However, the molecular mechanisms underlying the regulation of the cellular abundance and activity of ER-α remain unclear. We here show that the protein phosphatase calcineurin regulates both ER-α stability and activity in human breast cancer cells. Calcineurin depletion or inhibition down-regulated the abundance of ER-α by promoting its polyubiquitination and degradation. Calcineurin inhibition also promoted the binding of ER-α to the E3 ubiquitin ligase E6AP, and calcineurin mediated the dephosphorylation of ER-α at Ser294 in vitro. Moreover, the ER-α (S294A) mutant was more stable and activated the expression of ER-α target genes to a greater extent compared with the wild-type protein, whereas the extents of its interaction with E6AP and polyubiquitination were attenuated. These results suggest that the phosphorylation of ER-α at Ser294 promotes its binding to E6AP and consequent degradation. Calcineurin was also found to be required for the phosphorylation of ER-α at Ser118 by mechanistic target of rapamycin complex 1 and the consequent activation of ER-α in response to β-estradiol treatment. Our study thus indicates that calcineurin controls both the stability and activity of ER-α by regulating its phosphorylation at Ser294 and Ser118. Finally, the expression of the calcineurin A–α gene (PPP3CA) was associated with poor prognosis in ER-α–positive breast cancer patients treated with tamoxifen or other endocrine therapeutic agents. Calcineurin is thus a promising target for the development of therapies for ER-α–positive 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 FAK-Copy-Gain Is a Predictive Marker for Sensitivity to FAK Inhibition in Breast Cancer

Cancers ◽  
2019 ◽  
Vol 11 (9) ◽  
pp. 1288 ◽  
Author(s):  
Young-Ho Kim ◽  
Hyun-Kyoung Kim ◽  
Hee Yeon Kim ◽  
HyeRan Gawk ◽  
Seung-Hyun Bae ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Cancer Cells ◽  
Candidate Genes ◽  
Breast Cancer Cells ◽  
Target Genes ◽  
Xenograft Model ◽  
Predictive Marker ◽  
Marker Genes ◽  
Mouse Xenograft Model ◽  
Apoptotic Effect

Background: Cancers with copy-gain drug-target genes are excellent candidates for targeted therapy. In order to search for new predictive marker genes, we investigated the correlation between sensitivity to targeted drugs and the copy gain of candidate target genes in NCI-60 cells. Methods: For eight candidate genes showing copy gains in NCI-60 cells identified in our previous study, sensitivity to corresponding target drugs was tested on cells showing copy gains of the candidate genes. Results: Breast cancer cells with Focal Adhesion Kinase (FAK)-copy-gain showed a significantly higher sensitivity to the target inhibitor, FAK inhibitor 14 (F14). In addition, treatment of F14 or FAK-knockdown showed a specific apoptotic effect only in breast cancer cells showing FAK-copy-gain. Expression-profiling analyses on inducible FAK shRNA-transfected cells showed that FAK/AKT signaling might be important to the apoptotic effect by target inhibition. An animal experiment employing a mouse xenograft model also showed a significant growth-inhibitory effect of F14 on breast cancer cells showing FAK-copy-gain, but not on those without FAK-copy-gain. Conclusion: FAK-copy-gain may be a predictive marker for FAK inhibition therapy in breast cancer.

scholarly journals Identification of target genes of transcription factor activator protein 2 gamma in breast cancer cells

BMC Cancer ◽  
2009 ◽  
Vol 9 (1) ◽  
Author(s):  
He Ailan ◽  
Xiao Xiangwen ◽  
Ren Daolong ◽  
Gan Lu ◽  
Ding Xiaofeng ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Transcription Factor ◽  
Cancer Cells ◽  
Breast Cancer Cells ◽  
Target Genes ◽  
Activator Protein ◽  
Activator Protein 2

Identification of cytokine-induced nuclear factor-kappaB target genes in ovarian and breast cancer cells

2002 ◽  
Vol 64 (5-6) ◽  
pp. 873-881 ◽  
Author(s):  
Valérie Deregowski ◽  
Sylvie Delhalle ◽  
Valérie Benoit ◽  
Vincent Bours ◽  
Marie-Paule Merville
Keyword(s):  
Breast Cancer ◽  
Cancer Cells ◽  
Breast Cancer Cells ◽  
Target Genes ◽  
Nuclear Factor Kappab ◽  
Nuclear Factor

scholarly journals Global transcriptome analysis reveals partial estrogen-like effects of karanjin in MCF-7 breast cancer cells

2021 ◽  
Author(s):  
Gaurav Bhatt ◽  
Akshita Gupta ◽  
Latha Rangan ◽  
Anil Mukund Limaye
Keyword(s):  
Breast Cancer ◽  
Cancer Cells ◽  
Breast Cancer Cells ◽  
Target Genes ◽  
Biological Activities ◽  
Biological Effects ◽  
Dependent Manner ◽  
Cell Type ◽  
Concentration Dependent Manner ◽  
Mcf 7

Karanjin, an abundantly occurring furanoflavonoid in edible and non-edible legumes, exerts diverse biological effects in vivo, and in vitro. Its potential as an anticancer agent is also gaining traction following recent demonstrations of its anti-proliferative, cell cycle inhibitory, and pro-apoptotic effects. However, the universality of its anticancer potential is yet to be scrutinized, particularly so because flavonoids can act as selective estrogen receptor modulators (SERMs). Even the genomic correlates of its biological activities are yet to be examined in hormone responsive cells. This paper presents the early and direct transcriptomic footprint of 10 μM karanjin in MCF-7 breast cancer cells, using next generation sequencing technology (RNA-seq). We show that karanjin-modulated gene-expression repertoire is enriched in several hallmark gene sets, which include early estrogen-response, and G2/M checkpoint genes. Genes modulated by karanjin overlapped with those modulated by 1 nM 17β-estradiol (E2), or 1 μM tamoxifen. Karanjin altered the expression of selected estrogen-regulated genes in a cell-type, and concentration dependent manner. It downmodulated the expression of ERα protein in MCF-7 cells. Furthermore, ERα knockdown negatively impacted karanjins ability to modulate the expression of selected E2 target genes. Our data suggest that karanjin exerts its effects on ERα-positive breast cancer cells, at least in part, via ERα. The apparent SERM-like effects of karanjin pose a caveat to the anticancer potential of karanjin. In-depth studies on cell-type and concentration-dependent effects of karanjin may bring out its true potential in endocrine therapies.

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