PRPS1 silencing reverses cisplatin resistance in human breast cancer cells

2017 ◽  
Vol 95 (3) ◽  
pp. 385-393 ◽  
Author(s):  
Min He ◽  
Lin Chao ◽  
Yi-Ping You

PRPS1 (phosphoribosyl pyrophosphate synthetase 1), which drives the nucleotide biosynthesis pathway, modulates a variety of functions by providing central building blocks and cofactors for cell homeostasis. As tumor cells often display abnormal nucleotide metabolism, dysregulated de-novo nucleotide synthesis has potential impacts in cancers. We now report that PRPS1 is specifically and highly expressed in chemoresistant (CR) cancer cells derived from cisplatin-resistant human breast cancer cell lines SK-BR-3 and MCF-7. The inhibition of PRPS1 activity in CR cells by genetic silencing reduces cell viability and increases apoptosis in vitro, both of which can be further potentiated by cisplatin treatment. Significantly, such down-regulation of PRPS1 in CR cells when administered to nude mice enhanced the survival of those animals, as demonstrated by decreased tumor growth. Knockdown of PRPSI may cause these effects by potently inducing autonomous activation of caspase-3 and inhibiting the proliferation in the engrafted CR tumors. As a result, cisplatin sensitivity in a xenograft model of CR cancer cells can be restored by the down-regulation of PRPS1. Thus, PRPS1 inhibition may afford a therapeutic approach to relapsed patients with breast cancer, resistant to chemotherapy.

1989 ◽  
Vol 7 (6) ◽  
pp. 710-717 ◽  
Author(s):  
C K Osborne ◽  
L Kitten ◽  
C L Arteaga

In a prior National Surgical Adjuvant Breast and Bowel Project (NSABP) adjuvant study, the addition of the antiestrogen tamoxifen to chemotherapy with melphalan and fluorouracil adversely affected survival in several patient subsets, suggesting an antagonistic drug interaction. To investigate this possibility, we studied the interaction of tamoxifen and other antiestrogens with several cytotoxic drugs in cultured human breast cancer cell lines. Clinically relevant concentrations of tamoxifen and melphalan reduced colony survival of estrogen receptor (ER)-positive breast cancer cells when used alone in a colony-forming assay. However, pretreatment of cells with tamoxifen followed by exposure to melphalan resulted in antagonism, with more colonies surviving treatment with the combination than with melphalan alone. Identical effects were seen using several other triphenylethelene antiestrogens. An antagonistic interaction was observed even with a brief preincubation with tamoxifen that had no effect on cell proliferation, indicating that antagonism was not due to tamoxifen's known cell kinetic effects. Tamoxifen even antagonized melphalan cytotoxicity in ER-negative breast cancer cells and in cultured liver cells. An additive drug interaction occurred when melphalan was combined with pharmacologic concentrations of estradiol or medroxyprogesterone acetate, but antagonism was also observed with dexamethasone. Tamoxifen also antagonized the cytotoxicity of fluorouracil in these cells. However, an additive interaction occurred when the antiestrogen was combined with doxorubicin or 4-hydroxy-cyclophosphamide, an alkylating agent that is transported into the cell by a different carrier-mediated mechanism than melphalan. To avoid potential antagonism in the clinic, combinations of tamoxifen with melphalan and/or fluorouracil should be avoided.


2007 ◽  
Vol 14 (1) ◽  
pp. 61-72 ◽  
Author(s):  
Marina Brama ◽  
Sabrina Basciani ◽  
Sara Cherubini ◽  
Stefania Mariani ◽  
Silvia Migliaccio ◽  
...  

Inhibition of platelet-derived growth factor receptor (PDGFR) signaling restricts the growth of human breast cancer in the bone of nude mice. We hypothesized that osteoblast-secreted substances may alter the response capacity of breast cancer cells to the PDGFRs tyrosine kinase inhibitor imatinib mesylate. We found that osteoblast-conditioned medium (OCM) increases the proliferation rate of the estrogen receptor negative (ER−) MDA-MB-231 and of the ER+ MCF-7 human breast cancer cell lines and the growth-promoting effect on ER+ cells is independent from estrogen. OCM significantly improved the dose- and the time-dependent sensitivity of the tumor cells to the anti-proliferative effect of imatinib. We also found that MDA-MB-231 and MCF-7 cells express the two PDGFRs subtypes, PDGFR-α and PDGFR-β, and OCM treatment increases the expression of the PDGFRs. Furthermore, imatinib inhibited the phosphorylation rate of its target tyrosine kinase receptors. We conclude that bone microenvironment, through osteoblast-secreted substances may cause estrogen-independent proliferation of breast cancer cells by a mechanism mediated by the induction of PDGFRs expression. The enhanced sensitivity of OCM-treated breast cancer cells to imatinib would justify investigation on the efficacy of imatinib in bone breast cancer metastasis.


2016 ◽  
Vol 2 (4) ◽  
pp. 94 ◽  
Author(s):  
Sarojini S. ◽  
Senthilkumaar P. ◽  
Ramesh V.

The ethanol extract of Mikania glomerata has anti-proliferative effect on the human breast cancer cell lines. The object of the present work is to investigate the anti-cancer effect of Mikania glomerata ethanolic extract on breast cancer. Soxlet fractions using crude ethanolic extract of Mikania glomerata was prepared by standard extraction protocols. To check the antiproliferative effect of this extract, the extract chosen was tested for cell viability on the breast cancer cells MCF 7 in different concentrations. Cell viability was evaluated by MTT assay for 24 hour and 48 hours. The LD50 value was calculated and different morphometric assays were performed with the effective dose of the extract. The effect of the extract on the normal cell was evaluated as well. Cell proliferation, cell cycle, Clonogenic survival, Apoptosis and MTT assays were performed. The ethanolic extract showed a dose-dependent and time dependent inhibition on cell proliferation in the breast cancer cell lines. It showed low cytotoxicity in the normal cells and inhibited cellular adhesion and wound healing in treated cancer cells. The present study suggests that the leaf extract from Mikania glomerata induces anticancer effect on the breast cancer cells. Further study might help to confirm it as an anti-cancer drug.


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