Traditional Herbal Formula Taeeumjowi-Tang (TJ001) Inhibits p53-Mutant Prostate Cancer Cells Growth by Activating AMPK-Dependent Pathway.
ABSTRACT: 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.
Project description:BACKGROUND:We reported previously that phenethyl isothiocyanate (PEITC), a dietary compound, can reactivate p53R175H mutant in vitro and in SK-BR-3 (p53R175H) breast xenograft model resulting in tumor inhibition. Because of the diversity of human cancers with p53 mutations, these findings raise important questions whether this mechanism operates in different cancer types with same or different p53 mutations. In this study, we investigated whether PEITC recuses mutant p53 in prostate cancer cells harboring different types of p53 mutants, structural and contact, in vitro and in vivo. METHODS:Cell proliferation, cell apoptosis and cell cycle arrest assays were performed to examine the effects of PEITC on prostate cancer cell lines with p53 mutation(s), wild-type p53, p53 null or normal prostate cells in vitro. Western blot analysis was used to monitor the expression levels of p53 protein, activation of ATM and upregulation of canonical p53 targets. Immunoprecipitation, subcellular protein fraction and qRT-PCR was performed to determine change in conformation and restoration of transactivation functions/ inhibition of gain-of-function (GOF) activities to p53 mutant(s). Mice xenograft models were established to evaluate the antitumor efficacy of PEITC and PEITC-induced reactivation of p53 mutant(s) in vivo. Immunohistochemistry of xenograft tumor tissues was performed to determine effects of PEITC on expression of Ki67 and mutant p53 in vivo. RESULTS:We demonstrated that PEITC inhibits the growth of prostate cancer cells with different "hotspot" p53 mutations (structural and contact), however, preferentially towards structural mutants. PEITC inhibits proliferation and induces apoptosis by rescuing mutant p53 in p53R248W contact (VCaP) and p53R175H structural (LAPC-4) mutant cells with differential potency. We further showed that PEITC inhibits the growth of DU145 cells that co-express p53P223L (structural) and p53V274F (contact) mutants by targeting p53P223L mutant selectively, but not p53V274F. The mutant p53 restored by PEITC induces apoptosis in DU145 cells by activating canonical p53 targets, delaying cells in G1 phase and phosphorylating ATM. Importantly, PEITC reactivated p53R175H and p53P223L/V274F mutants in LAPC-4 and DU145 prostate xenograft models, respectively, resulting in significant tumor inhibition. CONCLUSION:Our studies provide the first evidence that PEITC's anti-cancer activity is cancer cell type-independent, but p53 mutant-type dependent.
Project description:Mitotic arrest induced by antimitotic drugs can cause apoptosis or p53-dependent cell cycle arrest. It can also cause DNA damage, but the relationship between these events has been unclear. Live, single-cell imaging in human cancer cells responding to an antimitotic kinesin-5 inhibitor and additional antimitotic drugs revealed strong induction of p53 after cells slipped from prolonged mitotic arrest into G1. We investigated the cause of this induction. We detected DNA damage late in mitotic arrest and also after slippage. This damage was inhibited by treatment with caspase inhibitors and by stable expression of mutant, noncleavable inhibitor of caspase-activated DNase, which prevents activation of the apoptosis-associated nuclease caspase-activated DNase (CAD). These treatments also inhibited induction of p53 after slippage from prolonged arrest. DNA damage was not due to full apoptosis, since most cytochrome C was still sequestered in mitochondria when damage occurred. We conclude that prolonged mitotic arrest partially activates the apoptotic pathway. This partly activates CAD, causing limited DNA damage and p53 induction after slippage. Increased DNA damage via caspases and CAD may be an important aspect of antimitotic drug action. More speculatively, partial activation of CAD may explain the DNA-damaging effects of diverse cellular stresses that do not immediately trigger apoptosis.
Project description:As a potential novel agent for treating pancreatic cancer, methylseleninic acid (MSeA) was evaluated in cell culture and xenograft models. Results showed that MSeA induced G1 cell cycle arrest and apoptosis in a majority of human and mouse pancreatic cancer cell lines, but G2 arrest in human PANC-1 and PANC-28 cell lines. In contrast to our previous finding in human prostate cancer LNCaP cells having a lack of P53 activation by MSeA, induction of G2 arrest in PANC-1 cells was accompanied by increased mutant P53 Ser15 phosphorylation, upregulation of P53-targets P21Cip1 and GADD45 and G2 checkpoint kinase (Chk2) activation, suggestive of DNA damage responses. A rapid inhibition of AKT phosphorylation was followed by reduced mTOR signaling and increased autophagy in PANC-1 cells attenuating caspase-mediated apoptosis execution. Furthermore, daily oral treatment with MSeA (3 mg Se/kg body weight) significantly suppressed growth of subcutaneously inoculated PANC-1 xenograft in SCID mice. Immunohistochemical analyses detected increased p-Ser15 P53, P21Cip1, pS139-H2AX (DNA damage responses), and caspase-3 cleavage and decreased pSer473AKT and Ki67 proliferative index and reduced intratumor vascular density in MSeA-treated xenograft. These results provide impetus for further research of MSeA in the therapy and/or chemoprevention of pancreatic cancer.
Project description:Targeting DNA repair with poly(ADP-ribose) polymerase (PARP) inhibitors has shown a broad range of anti-tumor activity in patients with advanced malignancies with and without BRCA deficiency. It remains unclear what role p53 plays in response to PARP inhibition in BRCA-proficient cancer cells treated with DNA damaging agents. Using gene expression microarray analysis, we find that DNA damage response (DDR) pathways elicited by veliparib (ABT-888), a PARP inhibitor, plus topotecan comprise the G1/S checkpoint, ATM, and p53 signaling pathways in p53-wildtype cancer cell lines and BRCA1, BRCA2 and ATR pathway in p53-mutant lines. In contrast, topotecan alone induces the G1/S checkpoint pathway in p53-wildtype lines and not in p53-mutant cells. These responses are coupled with G2/G1 checkpoint effectors p21(CDKN1A) upregulation, and Chk1 and Chk2 activation. The drug combination enhances G2 cell cycle arrest, apoptosis and a marked increase in cell death relative to topotecan alone in p53-wildtype and p53-mutant or -null cells. We also show that the checkpoint kinase inhibitor UCN-01 abolishes the G2 arrest induced by the veliparib and topotecan combination and further increases cell death in both p53-wildtype and -mutant cells. Collectively, PARP inhibition by veliparib enhances DDR and cell death in BRCA-proficient cancer cells in a p53-dependent and -independent fashion. Abrogating the cell-cycle arrest induced by PARP inhibition plus chemotherapeutics may be a strategy in the treatment of BRCA-proficient cancer.
Project description:Epigallocatechin gallate (EGCG) is the predominant tea polyphenol and it exhibits a hydrophilic character. The lipophilized EGCG derivative (LEGCG) was synthesized by enzymatic esterification of EGCG with lauric acid to enhance its bioactivity. The tetralauroyl EGCG was confirmed by high-performance liquid chromatography-tandem mass spectrometry and further identified as 3', 5', 3?, 5?-4-O-lauroyl EGCG by 1H and 13C nuclear magnetic resonance. The anti-proliferation effect of LEGCG on DU145 human prostate carcinoma cells was evaluated by MTT assay. In addition, the underlying molecular mechanism by which LEGCG exerts anti-proliferation efficacy was elucidated by flow cytometry and immunoblot analysis. Results suggested that LEGCG exhibited a dose-dependent anti-proliferation effect on DU145 cells by G0/G1 phase arrest and induction of apoptosis. LEGCG induced cell cycle arrest via p53/p21 activation, which down-regulated the cyclin D1 and CDK4 expression. In addition, LEGCG induced apoptosis by increasing the Bax/Bcl-2 ratio, the cytochrome c release, and the caspases cleavage on DU145 cells. The results provide theoretical support to prevent prostate cancer with LEGCG.
Project description:Hemistepsin A (HsA), a natural sesquiterpene lactone isolated from Hemistepta lyrata, has been known as a wide range of anti-tumor effects. The aim of this study was to determine whether HsA suppresses hepatocellular carcinoma (HCC) and to figure out the cellular signaling pathways involved in the anti-HCC activities by experiments using the Huh7 cells (a human HCC cell line) and a xenograft HCC model. In this study, HsA completely inhibited HCC cell proliferation, presumably because it induced G0/G1 cell cycle arrest and mitochondrial-related apoptosis. HsA up-regulated p53, p21, cleaved caspase-3 and cleaved PARP (poly (ADP-ribose) polymerase), but reduced cyclin D, CDK6 and Bcl-2 expressions, and it disrupted mitochondrial membrane potential (??m). Moreover, phosphorylation of AMP-activated protein kinase (AMPK) was increased by HsA as did the resveratrol and 5-aminoimidazole-4-carboxamide ribonucleotide (AICAR, positive controls). Inhibition of AMPK by using compound C, a competent inhibitor of AMPK, attenuated the loss of ??m, p53 up-regulation and cellular senescence. The efficacy of HsA to reduce HCC cell proliferation, compared to that of other known anti-HCC agents, appears to be similar or slightly better. The anti-tumor effect of HsA was also determined in mice, showing reduced growth of xenografted tumors with no weight loss. Overall, the results suggest that HsA should be considered as a candidate anti-HCC drug.
Project description:Background:The aim of the study was to evaluate whether the use of chemotherapy in combination with naringin, a dietary plant polyphenolic flavonoid, could enhance the therapeutic efficacy of paclitaxel treatment in human prostate cancer (PCa) cells. Materials and methods:DU145, PC3, and LNCaP cells were treated with various concentrations of paclitaxel, naringin, and their combinations. Methylthiazolyldiphenyl-tetrazolium bromide (MTT), image-based cytometer, quantitative reverse transcription PCR (RT-qPCR), Western blot, and transwell assay were used to evaluate cell viability, apoptosis and cell cycle, the mRNA expression, protein expression, and cell migration, respectively. Results:Naringin treatment inhibited cell survival in a dose- and time-dependent manner by inducing apoptosis and cell cycle arrest in G1 phase. Among the pathways evaluated, naringin (150 ?M) significantly induced the mRNA expressions of BAX, BID, caspase 3, cytochrome c, p53, p21 Cip1 , and p27 Kip1 and downregulated the expressions of survivin and livin in DU145 cells. The combination of naringin and paclitaxel treatments synergistically increased the cytotoxic effects of paclitaxel in androgen-independent DU145 and PC3 cells, as well as in androgen-sensitive LNCaP cells. The combination of naringin with docetaxel has almost the same inhibitory effect on cell proliferation as the paclitaxel combination in androgen-independent cells, whereas there is no similar effect in LNCaP cells. Naringin exhibits significant inhibitory effects on the cell migration ability. The flavonoid either alone or in combination with paclitaxel therapy resulted in an increase in tumor suppressor PTEN (phosphatase and tensin homolog deleted on chromosome 10) protein expression and decrease in nuclear factor-?B p50 protein level in DU145 cells. Conclusion:In conclusion, naringin acts as a chemosensitizer which synergistically strengths the cytotoxic effect of paclitaxel in PCa cells. Therefore, naringin therapy alone or in combination with paclitaxel may be useful in the treatment of PCa. However, there is a need for more detailed in vivo studies of the mechanism of action.
Project description:Primordial germ cells (PGCs) are embryonic founders of germ cells that ultimately differentiate into oocytes and spermatogonia. Embryonic proliferation of PGCs starting from E11.5 ensures the presence of germ cells in adulthood, especially in female mammals whose total number of oocytes declines after this initial proliferation period. To better understand mechanisms underlying PGC proliferation in female mice, we constructed a proteome profile of female mouse gonads at E11.5. Subsequent KEGG pathway analysis of the 3,662 proteins profiled showed significant enrichment of pathways involved in fatty acid degradation. Further, the number of PGCs found in in vitro cultured fetal gonads significantly decreased with application of etomoxir, an inhibitor of the key rate-limiting enzyme of fatty acid degradation carnitine acyltransferase I (CPT1). Decrease in PGCs was further determined to be the result of reduced proliferation rather than apoptosis. The inhibition of fatty acid degradation by etomoxir has the potential to activate the Ca(2+)/CamKII/5'-adenosine monophosphate-activated protein kinase (AMPK) pathway; while as an upstream activator, activated AMPK can function as activator of p53 to induce cell cycle arrest. Thus, we detected the expressional level of AMPK, phosphorylated AMPK (P-AMPK), phosphorylated p53 (P-p53) and cyclin-dependent kinase inhibitor 1 (p21) by Western blots, the results showed increased expression of them after treatment with etomoxir, suggested the activation of p53 pathway was the reason for reduced proliferation of PGCs. Finally, the involvement of p53-dependent G1 cell cycle arrest in defective proliferation of PGCs was verified by rescue experiments. Our results demonstrate that fatty acid degradation plays an important role in proliferation of female PGCs via the p53-dependent cell cycle regulation.
Project description:Aciculatin, a natural compound extracted from the medicinal herb Chrysopogon aciculatus, shows potent anti-cancer potency. This study is the first to prove that aciculatin induces cell death in human cancer cells and HCT116 mouse xenografts due to G1 arrest and subsequent apoptosis. The primary reason for cell cycle arrest and cell death was p53 accumulation followed by increased p21 level, dephosphorylation of Rb protein, PUMA expression, and induction of apoptotic signals such as cleavage of caspase-9, caspase-3, and PARP. We demonstrated that p53 allele-null (-/-) (p53-KO) HCT116 cells were more resistant to aciculatin than cells with wild-type p53 (+/+). The same result was achieved by knocking down p53 with siRNA in p53 wild-type cells, indicating that p53 plays a crucial role in aciculatin-induced apoptosis. Although DNA damage is the most common event leading to p53 activation, we found only weak evidence of DNA damage after aciculatin treatment. Interestingly, the aciculatin-induced downregulation of MDM2, an important negative regulator of p53, contributed to p53 accumulation. The anti-cancer activity and importance of p53 after aciculatin treatment were also confirmed in the HCT116 xenograft models. Collectively, these results indicate that aciculatin treatment induces cell cycle arrest and apoptosis via inhibition of MDM2 expression, thereby inducing p53 accumulation without significant DNA damage and genome toxicity.