scholarly journals Leptin-regulated gene expression in MCF-7 breast cancer cells: mechanistic insights into leptin-regulated mammary tumor growth and progression

2008 ◽  
Vol 199 (2) ◽  
pp. 221-233 ◽  
Author(s):  
Candida N Perera ◽  
Hwei G Chin ◽  
Nadire Duru ◽  
Ignacio G Camarillo

Obesity is a recently established risk factor for breast cancer incidence and mortality. A characteristic of obesity is elevated circulating levels of adipocyte-derived hormone leptin. Evidence indicates that leptin plays an important role in mammary tumor formation; however, the mechanisms involved are poorly understood. Toward better defining the role of leptin in breast cancer, we describe the identification of leptin-regulated genes in hormone-responsive Michigan Cancer Foundation-7 (MCF-7) human breast cancer cells using a microarray system. More than 64 leptin-regulated genes were identified including those for growth factors, cell cycle regulators, extracellular matrix (ECM) proteins, and genes associated with metastasis. Cell cycle genes up-regulated by leptin include cyclins D and G, cyclin-dependent kinase 2, p21, p27, and p16. Leptin suppressed the expression of transforming growth factor-β , a cell cycle suppressor. Determining the significance of this effect, treatment of MCF-7 cells with TGFB1 abrogated leptin-stimulated proliferation. Leptin up-regulated the expression of connective tissue growth factor, villin 2, and basigin, factors that are associated with ECM and are known to impact tumor growth. Finally, leptin induced the expression of anti-apoptotic genes BCL2 and survivin, and reduced the expression of apoptotic genes. The effect of leptin on MCF-7 survival was evaluated via TUNEL assay and demonstrated a sixfold reduction in apoptosis in leptin-treated cells, compared with controls. These data suggest leptin promotes mammary tumor growth through multiple mechanisms, including regulating the cell cycle, apoptosis, and by modulating the extracellular environment. The identification of leptin-regulated genes begins to provide mechanistic links into the relationship between obesity and breast cancer incidence and morbidity.

Endocrinology ◽  
2014 ◽  
Vol 155 (9) ◽  
pp. 3251-3261 ◽  
Author(s):  
Julia K. Blackmore ◽  
Sudipan Karmakar ◽  
Guowei Gu ◽  
Vaishali Chaubal ◽  
Liguo Wang ◽  
...  

Abstract The SMRT coregulator functions as a dual coactivator and corepressor for estrogen receptor-α (ERα) in a gene-specific manner, and in several studies its elevated expression correlates with poor outcome for breast cancer patients. A specific role of SMRT in breast cancer progression has not been elucidated, but SMRT knock-down limits estradiol-dependent growth of MCF-7 breast cancer cells. In this study, small-interfering RNA (siRNA) and short-hairpin RNA (shRNA) approaches were used to determine the effects of SMRT depletion on growth of ERα-positive MCF-7 and ZR-75–1 breast cancer cells, as well as the ERα-negative MDA-MB-231 breast cancer line. Depletion of SMRT inhibited growth of ERα-positive cells grown in monolayer but had no effect on growth of the ERα-negative cells. Reduced SMRT levels also negatively impacted the anchorage-independent growth of MCF-7 cells as assessed by soft agar colony formation assays. The observed growth inhibitions were due to a loss of estradiol-induced progression through the G1/S transition of the cell cycle and increased apoptosis in SMRT-depleted compared with control cells. Gene expression analyses indicated that SMRT inhibits apoptosis by a coordinated regulation of genes involved in apoptosis. Functioning as a dual coactivator for anti-apoptotic genes and corepressor for pro-apoptotic genes, SMRT can limit apoptosis. Together these data indicate that SMRT promotes breast cancer progression through multiple pathways leading to increased proliferation and decreased apoptosis.


Cancers ◽  
2021 ◽  
Vol 13 (12) ◽  
pp. 3043
Author(s):  
Ahmed Elwakeel ◽  
Anissa Nofita Sari ◽  
Jaspreet Kaur Dhanjal ◽  
Hazna Noor Meidinna ◽  
Durai Sundar ◽  
...  

We previously performed a drug screening to identify a potential inhibitor of mortalin–p53 interaction. In four rounds of screenings based on the shift in mortalin immunostaining pattern from perinuclear to pan-cytoplasmic and nuclear enrichment of p53, we had identified MortaparibPlus (4-[(1E)-2-(2-phenylindol-3-yl)-1-azavinyl]-1,2,4-triazole) as a novel synthetic small molecule. In order to validate its activity and mechanism of action, we recruited Luminal-A breast cancer cells, MCF-7 (p53wild type) and T47D (p53L194F) and performed extensive biochemical and immunocytochemical analyses. Molecular analyses revealed that MortaparibPlus is capable of abrogating mortalin–p53 interaction in both MCF-7 and T47D cells. Intriguingly, upregulation of transcriptional activation function of p53 (as marked by upregulation of the p53 effector gene—p21WAF1—responsible for cell cycle arrest and apoptosis) was recorded only in MortaparibPlus-treated MCF-7 cells. On the other hand, MortaparibPlus-treated T47D cells exhibited hyperactivation of PARP1 (accumulation of PAR polymer and decrease in ATP levels) as a possible non-p53 tumor suppression program. However, these cells did not show full signs of either apoptosis or PAR-Thanatos. Molecular analyses attributed such a response to the inability of MortaparibPlus to disrupt the AIF–mortalin complexes; hence, AIF did not translocate to the nucleus to induce chromatinolysis and DNA degradation. These data suggested that the cancer cells possessing enriched levels of such complexes may not respond to MortaparibPlus. Taken together, we report the multimodal anticancer potential of MortaparibPlus that warrants further attention in laboratory and clinical studies.


2015 ◽  
Vol 12 (2) ◽  
pp. 55-59
Author(s):  
Edy Meiyanto

As chemotherapeutic backbone for breast cancer therapy, doxorubicin showed various side effects and induced resistancy of breast cancer cells. Development of targeted therapy on breast cancer focused on combinatorial therapy of doxorubicin and molecular targeted agents. PGV-0 and PGV-1, a curcumin analogue showed potency as co-chemotherapeutic agent with doxorubicin. Our previous study of PGV-0 and PGV-1 showed cytotoxic activity in T47D cells. Therefore, the aim of this research is to examine the synergistic effect of PGV-0, PGV-1 on the cytotoxic activity of doxorubicin through cell cycle modulation and apoptotic induction on MCF-7 breast cancer cell lines. The cytotoxic assay of PGV-0, PGV-1, doxorubicin, and their combination were carried out by using MTT assay. Cell cycle distribution and apoptosis were determined by flowcytometer FACS-Calibur and the flowcytometry data was analyzed using Cell Quest program. Single treatment of PGV-0, PGV-1 and doxorubicin showed cytotoxic effect on MCF-7 with cell viability IC50 value 50 µM, 6 µM and 350 nM respectively. Single treatment of Doxorubicin 175 nM induced G2/M arrest. Single treatment of PGV-0 5 µM induced G2/M arrest while in higher dose 12.5  µM, PGV-0 induced apoptosis. Combination of doxorubicin 175 nM and PGV-0 5 µM induced apoptosis. Combination of doxorubicin 175 nM and PGV-0 12.5 µM also increased apoptosis induction. Single treatment of PGV-1 0.6 µM induced G1 arrest while in higher dose 1.5  µM, PGV-1 induced apoptosis. Combination of doxorubicin 175 nM and PGV-1 0.6 µM induced apoptosis. Combination of doxorubicin 175 nM and PGV-0 1.5 µM also increased apoptosis induction. PGV-0 and PGV-1 are potential to be delevoped as co-chemotherapeutic agent for breast cancer by inducing apoptosis and cell cycle modulation, but the molecular mechanism need to be explored detail.  Key words: PGV-0, PGV-1, doxorubicin, co-chemotherapy, breast cancer, cell cycle arrest, apoptosis


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