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

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.

Download Full-text

Calcineurin regulates the stability and activity of estrogen receptor α

Proceedings of the National Academy of Sciences ◽

10.1073/pnas.2114258118 ◽

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.

Download Full-text

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

Cancers ◽

10.3390/cancers11010043 ◽

2019 ◽

Vol 11 (1) ◽

pp. 43 ◽

Cited By ~ 2

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.

Download Full-text

FAK-Copy-Gain Is a Predictive Marker for Sensitivity to FAK Inhibition in Breast Cancer

Cancers ◽

10.3390/cancers11091288 ◽

2019 ◽

Vol 11 (9) ◽

pp. 1288 ◽

Cited By ~ 4

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.

Download Full-text

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

BMC Cancer ◽

10.1186/1471-2407-9-279 ◽

2009 ◽

Vol 9 (1) ◽

Cited By ~ 20

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

Download Full-text

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

Biochemical Pharmacology ◽

10.1016/s0006-2952(02)01151-6 ◽

2002 ◽

Vol 64 (5-6) ◽

pp. 873-881 ◽

Cited By ~ 20

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

Download Full-text

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

10.1101/2021.10.28.466373 ◽

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.

Download Full-text

Analysis of miRNA signature differentially expressed in exosomes from adriamycin-resistant and parental human breast cancer cells

Bioscience Reports ◽

10.1042/bsr20181090 ◽

2018 ◽

Vol 38 (6) ◽

Cited By ~ 5

Author(s):

Wei-xian Chen ◽

Ling-yun Xu ◽

Qi Qian ◽

Xiao He ◽

Wen-ting Peng ◽

...

Keyword(s):

Breast Cancer ◽

Cancer Cells ◽

Breast Cancer Cells ◽

Target Genes ◽

Expression Profiles ◽

Functional Enrichment ◽

Differentially Expressed ◽

Systematic Evaluation ◽

Mirna Signature ◽

Exosomal Mirnas

A major cause of failure in chemotherapy is drug resistance of cancer cells. Exosomes have been introduced to spread chemoresistance through delivering miRNAs. However, a systematic evaluation of the exosomal miRNA expression profiles responsible for chemoresistance is still lacking. In the present study, miRNA signature differentially expressed in exosomes derived from adriamycin-resistant (A/exo) and parental breast cancer cells (S/exo) were analyzed by microarray and the results were confirmed by PCR. A total of 309 miRNAs were increased and 66 miRNAs were decreased significantly in A/exo compared with S/exo. Specifically, 52 novel miRNAs with increased expression levels >16.0-fold in A/exo were identified. After prediction of target genes for 13 of 52 selected novel miRNAs, pathway analysis, gene ontology (GO) terms, and protein–protein interactions (PPIs) were constructed. The results implied that these selected exosomal miRNAs inhibited target genes involved in transcriptional misregulation in cancer, MAPK, and Wnt signaling pathways. Functional enrichment analysis demonstrated that the target genes were mainly responsible for protein phosphorylation, transcription regulation, molecular binding, and kinase activity. In summary, the current bioinformatics study of exosomal miRNAs may offer a new understanding into mechanisms of chemoresistance, which is helpful to find potential exosomal miRNAs to overcome drug insensitivity in future breast cancer treatment.

Download Full-text

Transcriptome Investigation and In Vitro Verification of Curcumin-Induced HO-1 as a Feature of Ferroptosis in Breast Cancer Cells

Oxidative Medicine and Cellular Longevity ◽

10.1155/2020/3469840 ◽

2020 ◽

Vol 2020 ◽

pp. 1-18

Author(s):

Ruihua Li ◽

Jing Zhang ◽

Yongfeng Zhou ◽

Qi Gao ◽

Rui Wang ◽

...

Keyword(s):

Breast Cancer ◽

Cell Death ◽

Cancer Cells ◽

Group Treatment ◽

Breast Cancer Cells ◽

Target Genes ◽

Specific Inhibitor ◽

Heme Oxygenase 1 ◽

Zinc Protoporphyrin ◽

Intracellular Iron

Ferroptosis is a form of oxidative cell death and has become a chemotherapeutic target for cancer treatment. Curcumin (CUR), a well-known cancer inhibitor, significantly inhibits the viability of breast cancer cells. Through transcriptomic analysis and flow cytometry experiments, it was found that after 48 hours of treatment of breast cancer cells at its half maximal inhibitory concentration (IC50), curcumin suppressed the viability of cancer cells via induction of ferroptotic death. Use of the ferroptosis inhibitor ferrostatin-1 and the iron chelator deferoxamine rescued cell death induced by curcumin. Furthermore, in subsequent cell validation experiments, the results showed that curcumin caused marked accumulation of intracellular iron, reactive oxygen species, lipid peroxides, and malondialdehyde, while glutathione levels were significantly downregulated. These changes are all manifestations of ferroptosis. Curcumin upregulates a variety of ferroptosis target genes related to redox regulation, especially heme oxygenase-1 (HO-1). Using the specific inhibitor zinc protoporphyrin 9 (ZnPP) to confirm the above experimental results showed that compared to the curcumin treatment group, treatment with ZnPP not only significantly improved cell viability but also reduced the accumulation of intracellular iron ions and other ferroptosis-related phenomena. Therefore, these data demonstrate that curcumin triggers the molecular and cytological characteristics of ferroptosis in breast cancer cells, and HO-1 promotes curcumin-induced ferroptosis.

Download Full-text

Transcription factor EGR3 is involved in the estrogen-signaling pathway in breast cancer cells

Journal of Molecular Endocrinology ◽

10.1677/jme.0.0320649 ◽

2004 ◽

Vol 32 (3) ◽

pp. 649-661 ◽

Cited By ~ 58

Author(s):

A Inoue ◽

Y Omoto ◽

Y Yamaguchi ◽

R Kiyama ◽

SI Hayashi

Keyword(s):

Breast Cancer ◽

Transcription Factor ◽

Cancer Cells ◽

Breast Cancer Cells ◽

Estrogen Receptor Alpha ◽

Target Genes ◽

Estrogen Signaling ◽

Upstream Region ◽

Custom Made ◽

Mcf 7

Estrogen has been closely associated with the genesis and malignant progression of breast cancer. However, the molecular mechanism underlying the effects of estrogen is far from being completely clarified. We previously developed a custom-made cDNA microarray consisting of approximately 200 estrogen-responsive genes in breast cancer cells. Using this system, we found one estrogen-induced gene in various cancer cell lines, including breast cancer MCF-7 cells, which encode a zinc-finger transcription factor, EGR3 (early growth response 3). Northern blot analysis of estradiol-treated MCF-7 cells showed rapid and robust induction of Egr3, and addition of cycloheximide or ICI 182,780 suggested that Egr3 is the bona fide target for the estrogen receptor alpha (ERalpha). Using stable transformants derived from MCF-7 cells which were transfected with expression-controllable Egr3-expression vector, we demonstrated that Nab2 is one of the target genes for EGR3. Microarray analysis of the transformants revealed other candidate EGR3-induced genes. These strategies could be useful for analyzing downstream genes of ERalpha, and may contribute to elucidating the extensive signaling network of estrogen stimuli. Furthermore, a reporter assay using the upstream region of fasL probably involving escape from the immune system revealed that fasL is another target gene for EGR3. The roles of EGR3 in the physiology of breast cancer are discussed.

Download Full-text