Abstract 98: TET suppresses protein translation, differentially effects polysome loading of cell cycle regulatory proteins and inhibits cell growth and proliferation of prostate cancer cells

Author(s):  
Praveen K. Jaiswal ◽  
Sweaty Koul ◽  
Qin Dong ◽  
Hari Koul
2015 ◽  
Vol 36 (5) ◽  
pp. 1982-1990 ◽  
Author(s):  
Li Xue ◽  
Hecheng Li ◽  
Qi Chen ◽  
Zhenlong Wang ◽  
Peng Zhang ◽  
...  

Background/Aims: Notch signaling pathway regulates cancer cell growth. RBPJ is a key transcription factor downstream of Notch receptor activation, whereas the role of RBPJ in carcinogenesis of prostate cancer is ill-defined. Methods: Here, we evaluated the effects of RBPJ inhibition on the growth of prostate cancer cells. We knocked down RBPJ in prostate cancer cells by a short hairpin interfering RNA (shRNA). We measured cell growth by an MTT assay. We analyzed the levels of cell-cycle-associated proteins by Western blot. Results: We found that shRNA for RBPJ efficiently inhibited RBPJ expression in prostate cancer cells, resulting in a significant decrease in the cell growth. Further, RBPJ-mediated cell-growth inhibition appeared to be resulting from alteration of cell-cycle inhibitors p21 and p27, cell-cycle activators CDK2, CDK4 and CyclinD1, and apoptosis-suppressor Bcl-2. Conclusion: Our data suggest that shRNA intervention of RBPJ expression could be a promising therapeutic approach for treating human prostate cancer.


2019 ◽  
Vol 2019 ◽  
pp. 1-11 ◽  
Author(s):  
Sooyeon Kang ◽  
Hyo In Kim ◽  
Yu-Jeong Choi ◽  
Seul Ki Lee ◽  
Ji Hye Kim ◽  
...  

Dysregulated lipid metabolism is a prominent feature of prostate cancers (PCas); several enzymes involved in lipid accumulation are highly expressed. Here, we elucidated efficacy of TJ001, a traditional herbal decoction, in inhibiting de novo lipogenesis. TJ001 had significant cytotoxicity against DU145 but not PC3 and LNCaP cells and, similarly, TJ001 markedly AMPK phosphorylation only in DU145 cells. This was accompanied by the downregulation of phosphorylated-acetyl coenzyme A carboxylase (ACC) expression and sterol regulatory element-binding protein 1 (SREBP1) proteolytic cleavage, thereby inhibiting its role as a transcription factor to induce lipid biosynthesis. When Oil Red O staining was performed, it is reflected in the reduction of lipid droplets (LDs). TJ001 also induced G1/S cell cycle arrest via a cell cycle inhibitor (CKI) p21WAF1/CIP1 upregulation. Although p53 proteins remained unchanged, both cyclin E and cyclin D1 were decreased. Moreover, TJ001 suppressed the mammalian target of rapamycin (mTOR) signaling pathway. Generally, the prolonged G1/S phase arrest accompanies apoptosis, but TJ001 failed to work as a trigger apoptosis in DU145 cells. We showed that mutant p53 proteins were required for the survival of DU145 cells. In presence of TJ001, inhibition of endogenous mutant p53 by RNAi led to cell viability reduction and induction of the p-AMPK/AMPK ratio. In addition, it induced apoptotic cell death in DU145 cells. At the cellular level, induction of PARP, caspase-3, and caspase-9 cleavages was observed, and caspase-3 activity was increased in the p53 knockdown cells treated with TJ001. Taken together, we demonstrated that TJ001 inhibited cell growth in DU145 prostate cancer cells as indicated by blocking lipogenesis and induction in G1/S cell cycle arrest. In addition, we may provide an evidence that mutant p53 protein has potential role as an oncogenic action in DU145 cells. Collectively, the combination of mutant p53 targeting and TJ001 treatment resulted in decreased cell growth in DU145 cells.


Oncogene ◽  
2001 ◽  
Vol 20 (23) ◽  
pp. 2927-2936 ◽  
Author(s):  
Sreenivasa R Chinni ◽  
Yiwei Li ◽  
Sunil Upadhyay ◽  
Prathima K Koppolu ◽  
Fazlul H Sarkar

2011 ◽  
Vol 21 (11) ◽  
pp. 1573-1578 ◽  
Author(s):  
Sang-Hun Kim ◽  
Kwang-Youn Kim ◽  
Sun-Nyoung Yu ◽  
Hyun-Joo Jeon ◽  
Young-Rang Jin ◽  
...  

2006 ◽  
Vol 24 (18_suppl) ◽  
pp. 20038-20038 ◽  
Author(s):  
A. O. Kaseb ◽  
S. Tejwani ◽  
K. Chinnakannu ◽  
E. Barrack ◽  
P. Reddy

20038 Background: Prostate cancer (CaP) that relapses following androgen-ablation therapy is hormone refractory, yet its growth continues to depend on androgen receptor (AR). Therefore, a curative strategy must include structural elimination of AR. Thymoquinone (TQ) is a component of Nigella sativa, an herb that has been used for thousands of years for a variety of diseases including cancer. We examined TQ effect on AR and cell cycle regulatory proteins required for proliferation and viability of CaP cells. Methods: Inhibitory effect of TQ on DNA synthesis and proliferation of exponentially growing LNCaP cells was assessed by 3H-thymidine incorporation into DNA and MTS assay respectively. We examined TQ effect on AR and cell cycle regulatory proteins by Western blot analysis. The effect of TQ on cell cycle progression was determined using synchronized LNCaP cells. Western blots were then used to analyze equal amounts of protein isolated from cells at regular intervals during their progression through the cell cycle in the presence or absence of TQ. Results: We observed a dose-dependent increase in the inhibitory effect of TQ on DNA synthesis and proliferation of LNCaP cells. We also observed a significant decrease in AR and E2F-1, and a dramatic increase in p21, p27, and pRB, and Bax. Synchronized LNCaP cells treated with TQ failed to enter S phase. Western blot analysis revealed that TQ treatment of synchronized cells resulted in: (i) a significant decrease in AR, that normally increases in early- to late-G1phase, and E2F-1, that normally increases in late-G1phase (ii) down-regulation of cyclins A and E, Cdks-2 and 4, and Cdc-6 (iii) induction of p53 and p27. Conclusion: These observations demonstrate that TQ inhibits proliferation and viability of prostate cancer cells by decreasing AR and E2F-1 levels and inducing the proteins that cause cell cycle arrest and promote apoptotic events. Thus TQ may prove to be an effective treatment of hormone refractory CaP and a promising chemo- and/or radiation- sensitizing agent in adjuvant therapy as well. This could represent a novel approach for treatment of prostate cancer by an herbal agent that was shown to spare normal cells in previous studies. No significant financial relationships to disclose.


2019 ◽  
Vol 18 (9) ◽  
pp. 1313-1322 ◽  
Author(s):  
Manjula Devi Ramamoorthy ◽  
Ashok Kumar ◽  
Mahesh Ayyavu ◽  
Kannan Narayanan Dhiraviam

Background: Reserpine, an indole alkaloid commonly used for hypertension, is found in the roots of Rauwolfia serpentina. Although the root extract has been used for the treatment of cancer, the molecular mechanism of its anti-cancer activity on hormonal independent prostate cancer remains elusive. Methods: we evaluated the cytotoxicity of reserpine and other indole alkaloids, yohimbine and ajmaline on Prostate Cancer cells (PC3) using MTT assay. We investigated the mechanism of apoptosis using a combination of techniques including acridine orange/ethidium bromide staining, high content imaging of Annexin V-FITC staining, flow cytometric quantification of the mitochondrial membrane potential and Reactive Oxygen Species (ROS) and cell cycle analysis. Results: Our results indicate that reserpine inhibits DNA synthesis by arresting the cells at the G2 phase and showed all standard sequential features of apoptosis including, destabilization of mitochondrial membrane potential, reduced production of reactive oxygen species and DNA ladder formation. Our in silico analysis further confirmed that indeed reserpine docks to the catalytic cleft of anti-apoptotic proteins substantiating our results. Conclusion: Collectively, our findings suggest that reserpine can be a novel therapeutic agent for the treatment of androgen-independent prostate cancer.


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