Celecoxib alleviates tamoxifen-instigated angiogenic effects by ROS-dependent VEGF-VEGFR2 autocrine signalingReport as inadecuate




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BMC Cancer

, 13:273

Experimental therapeutics and drug development

Abstract

BackgroundTamoxifen TAM is widely used in the chemotherapy of breast cancer and as a preventive agent against recurrence after surgery. However, extended TAM administration for breast cancer induces increased VEGF levels in patients, promoting new blood vessel formation and thereby limiting its efficacy. Celecoxib CXB, a selective COX-2 inhibitor, suppresses VEGF gene expression by targeting the VEGF promoter responsible for its inhibitory effect. For this study, we had selected CXB as non-steroidal anti-inflammatory drug in combination with TAM for suppressing VEGF expression and simultaneously reducing doses of both the drugs.

MethodsThe effects of CXB combined with TAM were examined in two human breast cancer cell lines in culture, MCF7 and MDA-MB-231. Assays of proliferation, apoptosis, angiogenesis, metastasis, cell cycle distribution, and receptor signaling were performed.

ResultsHere, we elucidated how the combination of TAM and CXB at nontoxic doses exerts anti-angiogenic effects by specifically targeting VEGF-VEGFR2 autocrine signaling through ROS generation. At the molecular level, TAM-CXB suppresses VHL-mediated HIF-1α activation, responsible for expression of COX-2, MMP-2 and VEGF. Besides low VEGF levels, TAM-CXB also suppresses VEGFR2 expression, confirmed through quantifying secreted VEGF levels, luciferase and RT-PCR studies. Interestingly, we observed that TAM-CXB was effective in blocking VEGFR2 promoter induced expression and further 2 fold decrease in VEGF levels was observed in combination than TAM alone in both cell lines. Secondly, TAM-CXB regulated VEGFR2 inhibits Src expression, responsible for tumor progression and metastasis. FACS and in vivo enzymatic studies showed significant increase in the reactive oxygen species upon TAM-CXB treatment.

ConclusionsTaken together, our experimental results indicate that this additive combination shows promising outcome in anti-metastatic and apoptotic studies. In a line, our preclinical studies evidenced that this additive combination of TAM and CXB is a potential drug candidate for treatment of breast tumors expressing high levels of VEGF and VEGFR2. This ingenious combination might be a better tailored clinical regimen than TAM alone for breast cancer treatment.

AbbreviationsTAMTamoxifen

CXBCelecoxib

VEGF-AVascular endothelial growth factor-A

VEGFR2Vascular endothelial growth factor receptor 2

COX-2Cycloxygenase-2

DCFDA2′,7′dichlorofluorescein diacetate

ROSReactive oxygen species

CATCatalase

SODSuperoxide dismutase

RT PCRReverse transcriptase polymerase reaction

EREstrogen receptor

STAT3Signal transducer and activator of transcription 3

MAPKMitogen-activated protein kinase

ELISAEnzyme-linked immunosorbent assay

PARPPolyADP-ribose polymerase

HUVECHuman umbilical vein endothelial cell

HIF-1αHypoxia-inducible factor 1α

PIPropidium iodide

DAPI4′,6-diamidino-2-phenylindole

MTT34,5-dimethylthiazol-2-yl-2,5 diphenyltetrazolium bromide

CBPCREB-binding protein

VHLvon Hippel-Lindau tumor suppressor protein

MMP-2Matrix metalloproteinase2

CAMChorioallantoic Membrane.

Electronic supplementary materialThe online version of this article doi:10.1186-1471-2407-13-273 contains supplementary material, which is available to authorized users.

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Author: B N Prashanth Kumar - Shashi Rajput - Kaushik Kumar Dey - Aditya Parekh - Subhasis Das - Abhijit Mazumdar - Mahitosh Man

Source: https://link.springer.com/



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