hPEBP4 Resists TRAIL-induced Apoptosis of Human Prostate Cancer Cells by Activating Akt and Deactivating ERK1/2 Pathways

The treatment options available for prostate cancer are limited because of its resistance to therapeutic agents. Thus, a better understanding of the underlying mechanisms of the resistance of prostate cancer will facilitate the discovery of more efficient treatment protocols. Human phosphatidylethanolamine-binding protein 4 (hPEBP4) is recently identified by us as an anti-apoptotic molecule and a potential candidate target for breast cancer treatment. Here we found the expression levels of hPEBP4 were positively correlated with the severity of clinical prostate cancer. Furthermore, hPEBP4 was not expressed in TRAIL-sensitive DU145 prostate cancer cells, but was highly expressed in TRAIL-resistant LNCaP cells, which show highly activated Akt. Interestingly, hPEBP4 overexpression in TRAIL-sensitive DU145 cells promoted Akt activation but inhibited ERK1/2 activation. The hPEBP4-overexpressing DU145 cells became resistant to TRAIL-induced apoptosis consequently, which could be reversed by PI3K inhibitors. In contrast, silencing of hPEBP4 in TRAIL-resistant LNCaP cells inhibited Akt activation but increased ERK1/2 activation, resulting in their sensitivity to TRAIL-induced apoptosis that was restored by the MEK1 inhibitor. Therefore, hPEBP4 expression in prostate cancer can activate Akt and deactivate ERK1/2 signaling, leading to TRAIL resistance. We also demonstrated that hPEBP4-mediated resistance to TRAIL-induced apoptosis occurred downstream of caspase-8 and at the level of BID cleavage via the regulation of Akt and ERK pathways, and that hPEBP4-regulated ERK deactivation was upstream of Akt activation in prostate cancer cells. Considering that hPEBP4 confers cellular resistance to TRAIL-induced apoptosis and is abundantly expressed in poorly differentiated prostate cancer, silencing of hPEBP4 suggests a promising approach for prostate cancer treatment.

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Calcitriol-Induced Apoptosis in LNCaP Cells Is Blocked By Overexpression of Bcl-21

Endocrinology ◽

10.1210/endo.141.1.7289 ◽

2000 ◽

Vol 141 (1) ◽

pp. 10-17 ◽

Cited By ~ 89

Author(s):

Sarah E. Blutt ◽

Timothy J. McDonnell ◽

Tara C. Polek ◽

Nancy L. Weigel

Keyword(s):

Prostate Cancer ◽

Cell Cycle ◽

Vitamin D ◽

Cancer Cells ◽

Mineral Metabolism ◽

Lncap Cells ◽

Prostate Cancer Cells ◽

Apoptotic Pathway ◽

Induced Apoptosis

Abstract While the role of vitamin D in bone and mineral metabolism has been investigated extensively, the role of the vitamin D receptor in other tissues is less well understood. 1,25-dihydroxyvitamin D3 (calcitriol) can act as a differentiating agent in normal tissues and can inhibit the growth of many cancer cell lines including LNCaP prostate cancer cells. We have shown previously that calcitriol causes LNCaP cell accumulation in the G0/G1 phase of the cell cycle. In this study, we demonstrate that calcitriol also induces apoptosis of LNCaP cells. The calcitriol-induced apoptosis is accompanied by a down-regulation of Bcl-2 and Bcl-XL proteins, both of which protect cells from undergoing apoptosis. Other proteins important in apoptotic control, Bax, Mcl-1, and Bcl-Xs, are unaffected by calcitriol treatment. We find that overexpression of Bcl-2 blocks calcitriol-induced apoptosis and reduces, but does not eliminate, calcitriol-induced growth inhibition. We conclude that both regulation of cell cycle and the apoptotic pathway are involved in calcitriol action in prostate cancer cells.

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tRNALys-Derived Fragment Alleviates Cisplatin-Induced Apoptosis in Prostate Cancer Cells

Pharmaceutics ◽

10.3390/pharmaceutics13010055 ◽

2021 ◽

Vol 13 (1) ◽

pp. 55

Author(s):

Changwon Yang ◽

Minkyeong Lee ◽

Gwonhwa Song ◽

Whasun Lim

Keyword(s):

Prostate Cancer ◽

Cancer Cells ◽

Suppressor Gene ◽

Prostate Cancer Cells ◽

Apoptotic Pathway ◽

Normal Prostate ◽

Prostate Cells ◽

Du145 Cells ◽

Induced Apoptosis ◽

Related Proteins

Cisplatin is a standard treatment for prostate cancer, which is the third leading cause of cancer-related deaths among men globally. However, patients who have undergone cisplatin can rxperience relapse. tRNA-derived fragments (tRFs) are small non-coding RNAs generated via tRNA cleavage; their physiological activities are linked to the development of human diseases. Specific tRFs, including tRF-315 derived from tRNALys, are highly expressed in prostate cancer patients. However, whether tRF-315 regulates prostate cancer cell proliferation or apoptosis is unclear. Herein, we confirmed that tRF-315 expression was higher in prostate cancer cells (LNCaP, DU145, and PC3) than in normal prostate cells. tRF-315 prevented cisplatin-induced apoptosis and alleviated cisplatin-induced mitochondrial dysfunction in LNCaP and DU145 cells. Moreover, transfection of tRF-315 inhibitor increased the expression of apoptotic pathway-related proteins in LNCaP and DU145 cells. Furthermore, tRF-315 targeted the tumor suppressor gene GADD45A, thus regulating the cell cycle, which was altered by cisplatin in LNCaP and DU145 cells. Thus, tRF-315 protects prostate cancer cells from mitochondrion-dependent apoptosis induced by cisplatin treatment.

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Cytostatic Action of Novel Histone Deacetylase Inhibitors in Androgen Receptor-Null Prostate Cancer Cells

Pharmaceuticals ◽

10.3390/ph14020103 ◽

2021 ◽

Vol 14 (2) ◽

pp. 103

Author(s):

Zohaib Rana ◽

Joel D. A. Tyndall ◽

Muhammad Hanif ◽

Christian G. Hartinger ◽

Rhonda J. Rosengren

Keyword(s):

Prostate Cancer ◽

Androgen Receptor ◽

Cancer Cells ◽

Hdac Inhibitors ◽

G1 Arrest ◽

Prostate Cancer Cells ◽

Prostate Tumors ◽

Normal Prostate ◽

Pc3 Cells ◽

Du145 Cells

Androgen receptor (AR)-null prostate tumors have been observed in 11–24% of patients. Histone deacetylases (HDACs) are overexpressed in prostate tumors. Therefore, HDAC inhibitors (Jazz90 and Jazz167) were examined in AR-null prostate cancer cell lines (PC3 and DU145). Both Jazz90 and Jazz167 inhibited the growth of PC3 and DU145 cells. Jazz90 and Jazz167 were more active in PC3 cells and DU145 cells in comparison to normal prostate cells (PNT1A) and showed a 2.45- and 1.30-fold selectivity and higher cytotoxicity toward DU145 cells, respectively. Jazz90 and Jazz167 reduced HDAC activity by ~60% at 50 nM in PC3 lysates. At 4 μM, Jazz90 and Jazz167 increased acetylation in PC3 cells by 6- to 8-fold. Flow cytometry studies on the cell phase distribution demonstrated that Jazz90 causes a G0/G1 arrest in AR-null cells, whereas Jazz167 leads to a G0/G1 arrest in DU145 cells. However, apoptosis only occurred at a maximum of 7% of the total cell population following compound treatments in PC3 and DU145 cells. There was a reduction in cyclin D1 and no significant changes in bcl-2 in DU145 and PC3 cells. Overall, the results showed that Jazz90 and Jazz167 function as cytostatic HDAC inhibitors in AR-null prostate cancer cells.

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