Oral Naftopidil Suppresses Human Renal-Cell Carcinoma by Inducing G1 Cell-Cycle Arrest in Tumor and Vascular Endothelial Cells

Abstract

Renal cell carcinoma (RCC) is an angiogenesis-dependent and hypoxia-driven malignancy. As a result, several targeting agents are being investigated. However, the efficacy of current regimens is generally insufficient for their toxicity and poor overall response rates. We have recently reported that naftopidil exerts growth-inhibitory effects on human prostate cancer cells. In this study, we investigated the biochemical mechanisms by which naftopidil produces growth-inhibitory and antiangiogenic effects on RCC. We first tested the effects of naftopidil on the proliferation of ACHN and Caki-2 RCC cells. Next, we set up a model simulating the tumor microenvironment, in which ACHN cells were grafted onto the renal capsule of mice. We then tested the effects of naftopidil on human umbilical vein endothelial cells' cell proliferation and Matrigel plug vascularization. Finally, to establish the antitumor activity of naftopidil on RCC, we tested the antitumor effects of naftopidil on excised tumor specimens from 20 patients with RCC that were grafted beneath the renal capsule of mice. Naftopidil showed similar in vitro growth-inhibitory effects on all cell lines. Fluorescence-activated cell sorting analysis revealed an increase in G 1 cell-cycle arrest in all naftopidil-treated cell lines. In vivo tumorigenic studies showed a significant reduction of ACHN tumor weight, Ki-67 index, and microvessel density (MVD) in naftopidil-treated mice. Naftopidil attenuated neovascularization in an in vivo Matrigel plug assay. Studies in mouse xenograft models also showed a significant MVD reduction in naftopidil-treated excised human RCC. The growth-inhibitory effects of naftopidil suggest it may be a novel anticancer agent and a potential preventive option for RCC. Cancer Prev Res; 6(9); 1000-6. Ó2013 AACR.

Fibroblasts prolong serum prostate-specific antigen decline after androgen deprivation therapy in prostate cancer

“…The amount of Evans blue eluted with formamide from the Matrigel plugs was measured with a spectrophotometer (620 nm), as previously described. 25 Statistical Analysis Data are presented as the mean ± s.d. Statistically significant differences between two groups were determined using Student's t-test.…”

Identification of a new pharmacological activity of the phenylpiperazine derivative naftopidil: tubulin-binding drug

“…Previously, unique growth-inhibitory effects of naftopidil have been reported, in vivo suppression of tumor growth in human prostate cancer cells and human renal cell carcinoma cells [3][4][5]. In vitro analyses of naftopidil showed inhibition of cell cycle progression not only in human prostate cancer cells and human renal cell carcinoma cells, but also in human prostatic fibroblasts and human vascular endothelial cells [4,5].…”

“…In vitro analyses of naftopidil showed inhibition of cell cycle progression not only in human prostate cancer cells and human renal cell carcinoma cells, but also in human prostatic fibroblasts and human vascular endothelial cells [4,5]. Interestingly, Hori [4] demonstrated evidence that naftopidil-inhibited cell cycle progression was independent of α 1 -AR expression, suggesting that the antiproliferative effects of naftopidil may be due to the off-target effects of this drug.…”

Possible new therapeutic agents for malignant pleural mesothelioma: anti-CD26 monoclonal antibody and naftopidil

“…Recently, it was shown that naftopidil exerts an antitumor action on prostate cancer cells and renal cell carcinoma by arresting cells in the G 1 phase of the cell cycle. In addition, the prostate cancer incidence was significantly lower in men who received naftopidil for ≥3 months than in those who received tamsulosin [21,22].…”

“…Naftopidil has been shown to attenuate neovascularization in an in vivo Matrigel plug assay. Moreover, studies in mouse xenograft models have shown a significant microvessel density reduction in naftopidil-treated excised human renal cell carcinoma [22]. Naftopidil induces apoptosis of mesothelioma cells by upregulating the expression of TNF-α and stimulating the secretion of FasL, a ligand for the death receptor Fas, both of which activate caspase-8 and the effector caspase-3, which lead to the suppression of mesothelioma cell proliferation in vivo [24].…”