Penfluridol

Penfluridol is a highly potent, first generation diphenylbutylpiperidine antipsychotic.

Anti-tumor effects of penfluridol through dysregulation of cholesterol homeostasis.[Pubmed:24528079]

Asian Pac J Cancer Prev. 2014;15(1):489-94.

BACKGROUND: Psychiatric patients appear to be at lower risk of cancer. Some antipsychotic drugs might have inhibitory effects on tumor growth, including Penfluridol, a strong agent. To test this, we conducted a study to determine whether Penfluridol exerts cytotoxic effects on tumor cells and, if so, to explore its anti-tumor mechanisms. METHODS: Growth inhibition of mouse cancer cell lines by Penfluridol was determined using the 3- (4, 5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide (MTT) assay. Cytotoxic activity was determined by clonogenic cell survival and trypan blue assays. Animal tumor models of these cancer cells were established and to evaluate Penfluridol for its anti-tumor efficacy in vivo. Unesterified cholesterol in cancer cells was examined by filipin staining. Serum total cholesterol and tumor total cholesterol were detected using the cholesterol oxidase/p- aminophenazone (CHOD-PAP) method. RESULTS: Penfluridol inhibited the proliferation of B16 melanoma (B16/ F10), LL/2 lung carcinoma (LL/2), CT26 colon carcinoma (CT26) and 4T1 breast cancer (4T1) cells in vitro. In vivo Penfluridol was particularly effective at inhibiting LL/2 lung tumor growth, and obviously prolonged the survival time of mice bearing LL/2 lung tumors implanted subcutaneously. Accumulated unesterified cholesterol was found in all of the cancer cells treated with Penfluridol, and this effect was most evident in LL/2, 4T1 and CT26 cells. No significant difference in serum cholesterol levels was found between the normal saline-treated mice and the Penfluridol-treated mice. However, a dose-dependent decrease of total cholesterol in tumor tissues was observed in Penfluridol-treated mice, which was most evident in B16/F10-, LL/2-, and 4T1-tumor-bearing mice. CONCLUSION: Our results suggested that Penfluridol is not only cytotoxic to cancer cells in vitro but can also inhibit tumor growth in vivo. Dysregulation of cholesterol homeostasis by Penfluridol may be involved in its anti-tumor mechanisms.

Penfluridol Represses Integrin Expression in Breast Cancer through Induction of Reactive Oxygen Species and Downregulation of Sp Transcription Factors.[Pubmed:27811009]

Mol Cancer Ther. 2017 Jan;16(1):205-216.

It was recently demonstrated the Penfluridol inhibited breast tumor growth and metastasis and this was associated with downregulation of alpha6- and beta4-integrins. In this study, we observed the Penfluridol induced reactive oxygen species (ROS) and this was the primary mechanism of action. Penfluridol-mediated growth inhibition, induction of apoptosis, and inhibition of breast cancer cell migration was attenuated after cotreatment with glutathione. Penfluridol also downregulated Sp transcription factors Sp1, Sp3, and Sp4 through epigenetic downregulation of cMyc and cMyc-regulated miRNAs (miR27a and miR20a/miR17) and induction of the miR-regulated Sp transcriptional repressors ZBTB10 and ZBTB4. alpha6- and beta4-integrins as well as alpha5- and beta1-integrins are Sp-regulated genes that are also coregulated by the orphan nuclear receptor NR4A1 and these integrins can be targeted by agents such as Penfluridol that suppress Sp1, Sp3, and Sp4 and also by NR4A1 antagonists. Mol Cancer Ther; 16(1); 205-16. (c)2016 AACR.

Penfluridol suppresses pancreatic tumor growth by autophagy-mediated apoptosis.[Pubmed:27189859]

Sci Rep. 2016 May 18;6:26165.

Pancreatic tumors exhibit enhanced autophagy as compared to any other cancer, making it resistant to chemotherapy. We evaluated the effect of Penfluridol against pancreatic cancer. Penfluridol treatment induced apoptosis and inhibited the growth of Panc-1, BxPC-3 and AsPC-1, pancreatic cancer cells with IC50 ranging between 6-7 muM after 24 h of treatment. Significant autophagy was induced by Penfluridol treatment in pancreatic cancer cells. Punctate LC3B and autophagosomes staining confirmed autophagy. Inhibiting autophagy by chloroquine, bafilomycin, 3-methyladenine or LC3BsiRNA, significantly blocked Penfluridol-induced apoptosis, suggesting that autophagy lead to apoptosis in our model. Penfluridol treatment suppressed the growth of BxPC-3 tumor xenografts by 48% as compared to 17% when treated in combination with chloroquine. Similarly, Penfluridol suppressed the growth of AsPC-1 tumors by 40% versus 16% when given in combination with chloroquine. TUNEL staining and caspase-3 cleavage revealed less apoptosis in the tumors from mice treated with Penfluridol and chloroquine as compared to Penfluridol alone. Penfluridol treatment also suppressed the growth of orthotopically implanted Panc-1 tumors by 80% by inducing autophagy-mediated apoptosis in the tumors. These studies established that Penfluridol inhibits pancreatic tumor growth by autophagy-mediated apoptosis. Since Penfluridol is already in clinic, positive findings from our study will accelerate its clinical development.

Penfluridol: An Antipsychotic Agent Suppresses Metastatic Tumor Growth in Triple-Negative Breast Cancer by Inhibiting Integrin Signaling Axis.[Pubmed:26627008]

Cancer Res. 2016 Feb 15;76(4):877-90.

Metastasis of breast cancer, especially to the brain, is the major cause of mortality. The inability of anticancer agents to cross the blood-brain-barrier represents a critical challenge for successful treatment. In the current study, we investigated the antimetastatic potential of Penfluridol, an antipsychotic drug frequently prescribed for schizophrenia with anticancer activity. We show that Penfluridol induced apoptosis and reduced the survival of several metastatic triple-negative breast cancer (TNBC) cell lines. In addition, Penfluridol treatment significantly reduced the expression of integrin alpha6, integrin beta4, Fak, paxillin, Rac1/2/3, and ROCK1 in vitro. We further evaluated the efficacy of Penfluridol in three different in vivo tumor models. We demonstrate that Penfluridol administration to an orthotopic model of breast cancer suppressed tumor growth by 49%. On the other hand, Penfluridol treatment inhibited the growth of metastatic brain tumors introduced by intracardiac or intracranial injection of breast cancer cells by 90% and 72%, respectively. Penfluridol-treated tumors from all three models exhibited reduced integrin beta4 and increased apoptosis. Moreover, chronic administration of Penfluridol failed to elicit significant toxic or behavioral side effects in mice. Taken together, our results indicate that Penfluridol effectively reduces the growth of primary TNBC tumors and especially metastatic growth in the brain by inhibiting integrin signaling, and prompt further preclinical investigation into repurposing Penfluridol for the treatment of metastatic TNBC.