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Single-cell analysis reveals androgen receptor regulates the ER-to-Golgi trafficking pathway with CREB3L2 to drive prostate cancer progression. Oncogene 2021; 40:6479-6493. [PMID: 34611310 DOI: 10.1038/s41388-021-02026-7] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2021] [Revised: 08/29/2021] [Accepted: 09/16/2021] [Indexed: 02/06/2023]
Abstract
Androgen receptor (AR) plays a central role in driving prostate cancer (PCa) progression. How AR promotes this process is still not completely clear. Herein, we used single-cell transcriptome analysis to reconstruct the transcriptional network of AR in PCa. Our work shows AR directly regulates a set of signature genes in the ER-to-Golgi protein vesicle-mediated transport pathway. The expression of these genes is required for maximum androgen-dependent ER-to-Golgi trafficking, cell growth, and survival. Our analyses also reveal the signature genes are associated with PCa progression and prognosis. Moreover, we find inhibition of the ER-to-Golgi transport process with a small molecule enhanced antiandrogen-mediated tumor suppression of hormone-sensitive and insensitive PCa. Finally, we demonstrate AR collaborates with CREB3L2 in mediating ER-to-Golgi trafficking in PCa. In summary, our findings uncover a critical role for dysregulation of ER-to-Golgi trafficking expression and function in PCa progression, provide detailed mechanistic insights for how AR tightly controls this process, and highlight the prospect of targeting the ER-to-Golgi pathway as a therapeutic strategy for advanced PCa.
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Zhang JM, Jiang YY, Huang QF, Lu XX, Wang GH, Shao CL, Liu M. Brefeldin A delivery nanomicelles in hepatocellular carcinoma therapy: Characterization, cytotoxic evaluation in vitro, and antitumor efficiency in vivo. Pharmacol Res 2021; 172:105800. [PMID: 34363949 DOI: 10.1016/j.phrs.2021.105800] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/07/2021] [Revised: 08/01/2021] [Accepted: 08/02/2021] [Indexed: 12/24/2022]
Abstract
Hepatocellular carcinoma (HCC) is one of the major cancers with high mortality rate. Traditional drugs used in clinic are usually limited by the drug resistance and side effect and novel agents are still needed. Macrolide brefeldin A (BFA) is a well-known lead compound in cancer chemotherapy, however, with poor solubility and instability. In this study, to overcome these disadvantages, BFA was encapsulated in mixed nanomicelles based on TPGS and F127 copolymers (M-BFA). M-BFA was conferred high solubility, colloidal stability, and capability of sustained release of intact BFA. In vitro, M-BFA markedly inhibited the proliferation, induced G0/G1 phase arrest, and caspase-dependent apoptosis in human liver carcinoma HepG2 cells. Moreover, M-BFA also induced autophagic cell death via Akt/mTOR and ERK pathways. In HepG2 tumor-bearing xenograft mice, indocyanine green (ICG) as a fluorescent probe loaded in M-BFA distributed to the tumor tissue rapidly, prolonged the blood circulation, and improved the tumor accumulation capacity. More importantly, M-BFA (10 mg/kg) dramatically delayed the tumor progression and induced extensive necrosis of the tumor tissues. Taken together, the present work suggests that M-BFA has promising potential in HCC therapy.
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Affiliation(s)
- Jin-Man Zhang
- Key Laboratory of Marine Drugs, The Ministry of Education of China, School of Medicine and Pharmacy, Ocean University of China, Qingdao 266003, China
| | - Yao-Yao Jiang
- Key Laboratory of Marine Drugs, The Ministry of Education of China, School of Medicine and Pharmacy, Ocean University of China, Qingdao 266003, China
| | - Qun-Fa Huang
- School of Pharmacy, Guangdong Medical University, Dongguan 523808, China
| | - Xu-Xiu Lu
- Key Laboratory of Marine Drugs, The Ministry of Education of China, School of Medicine and Pharmacy, Ocean University of China, Qingdao 266003, China
| | - Guan-Hai Wang
- School of Pharmacy, Guangdong Medical University, Dongguan 523808, China.
| | - Chang-Lun Shao
- Key Laboratory of Marine Drugs, The Ministry of Education of China, School of Medicine and Pharmacy, Ocean University of China, Qingdao 266003, China; Laboratory for Marine Drugs and Bioproducts, Qingdao National Laboratory for Marine Science and Technology, Qingdao 266200, China.
| | - Ming Liu
- Key Laboratory of Marine Drugs, The Ministry of Education of China, School of Medicine and Pharmacy, Ocean University of China, Qingdao 266003, China; Laboratory for Marine Drugs and Bioproducts, Qingdao National Laboratory for Marine Science and Technology, Qingdao 266200, China.
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Degen M, Alexander B, Choudhury M, Eshghi M, Konno S. Alternative therapeutic approach to renal-cell carcinoma: induction of apoptosis with combination of vitamin K3 and D-fraction. J Endourol 2014; 27:1499-503. [PMID: 24341344 DOI: 10.1089/end.2013.0207] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
PURPOSE Because of a dismal prognosis for advanced renal-cell carcinoma (RCC), an alternative therapeutic approach, using vitamin K3 (VK3) and D-fraction (DF) was investigated. VK3 is a synthetic VK derivative and DF is a bioactive mushroom extract, and they have been shown to have antitumor activity. We examined if the combination of VK3 and DF would exhibit the improved anticancer effect on RCC in vitro. MATERIALS AND METHODS Human RCC, ACHN cell line, were treated with varying concentrations of VK3, DF, or a combination of the two. Cell viability was assessed at 72 hours by MTT assay. To explore the possible anticancer mechanism, studies on cell cycle, chromatin modifications, and apoptosis were conducted. RESULTS VK3 alone led to a ~20% reduction in cell viability at 4 μM, while DF alone induced a 20% to 45% viability reduction at ≥ 500 μg/mL. A combination of VK3 (4 μM) and DF (300 μg/mL) led to a drastic >90% viability reduction, however. Cell cycle analysis indicated that VK3/DF treatment induced a G1 cell cycle arrest, accompanied by the up-regulation of p21(WAF1) and p27(Kip1). Histone deacetylase (HDAC) was also significantly (~60%) inactivated, indicating chromatin modifications. In addition, Western blot analysis revealed that the up-regulation of Bax and activation of poly-(ADP-ribose)-polymerase (PARP) were seen in VK3/DF-treated cells, indicating induction of apoptosis. CONCLUSIONS The combination of VK3 and DF can lead to a profound reduction in ACHN cell viability, through a p21(WAF1)-mediated G1 cell cycle arrest, and ultimately induces apoptosis. Therefore, the combination of VK3/DF may have clinical implications as an alternative, improved therapeutic modality for advanced RCC.
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Affiliation(s)
- Michael Degen
- Department of Urology, New York Medical College , Valhalla, New York
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Alexander B, Fishman AI, Eshghi M, Choudhury M, Konno S. Induction of cell death in renal cell carcinoma with combination of D-fraction and vitamin C. Integr Cancer Ther 2013; 12:442-8. [PMID: 23341484 DOI: 10.1177/1534735412473643] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
HYPOTHESIS Although several conventional therapeutic options for advanced renal cell carcinoma (RCC) are currently available, the unsatisfactory outcomes demand establishing more effective interventions. D-fraction (PDF), a bioactive proteoglucan of Maitake mushroom, demonstrates anticancer and immunomodulatory activities, which are also shown to be potentiated by vitamin C (VC). We thus hypothesized that a combination of PDF and VC (PDF + VC) could be an alternative approach to more effectively inhibit the growth of RCC. STUDY DESIGN We examined the dose-dependent effects of PDF + VC on RCC cell viability and also performed biochemical assays to explore the growth regulatory mechanism. METHODS Human RCC, ACHN cell line, was employed and exposed to varying concentrations of PDF or VC and their combinations. Cell viability at specified times was determined by MTT assay. Lipid peroxidation assay, cell cycle analysis, and Western blot analysis were also performed. RESULTS PDF or VC alone led to the significant reduction in cell viability at 72 hours with PDF >500 µg/mL and VC ≥300 µM. When various combinations of PDF and VC were tested, the combination of the ineffective concentrations of PDF (300 µg/mL) and VC (200 µM) resulted in ~90% cell death in 24 hours. Lipid peroxidation assay then indicated significantly (~2.5 fold) elevated oxidative stress with this PDF + VC. Cell cycle analysis also indicated a G1 cell cycle arrest following a 6-hour PDF + VC treatment. Western blots further revealed a downregulation of Bcl2, an upregulation of Bax, and proteolytic activation of PARP (poly[ADP-ribose] polymerase) in PDF + VC-treated cells, indicating induction of apoptosis. CONCLUSION The present study demonstrates that the combination of PDF and VC can become highly cytotoxic, inducing severe cell death in ACHN cells. This cytotoxic mechanism appears to be primarily attributed to oxidative stress, accompanied by a G1 cell cycle arrest. Such cell death induced by PDF + VC could be more likely linked to apoptosis, as indicated by the modulation of apoptosis regulators (Bcl2, Bax, and PARP). Therefore, as PDF and VC may work synergistically to induce apoptotic cell death, they may have clinical implications in an alternative, improved therapeutic modality for advanced RCC.
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Fishman AI, Alexander B, Eshghi M, Choudhury M, Konno S. Nephrotoxin-induced renal cell injury involving biochemical alterations and its prevention with antioxidant. J Clin Med Res 2012; 4:95-101. [PMID: 22505981 PMCID: PMC3320129 DOI: 10.4021/jocmr833w] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/16/2012] [Indexed: 11/04/2022] Open
Abstract
Background Although nephrotoxic agents or nephrotoxins are known to induce acute renal cell injury, their cytotoxic action is not fully elucidated. It is thus crucial to explore such a cytotoxic mechanism and the increasing volume of reports indicated a significant involvement of oxidative stress. To test this possibility, we investigated if a nephrotoxin would exert oxidative stress, leading to renal cell injury accompanied by certain biochemical alterations. We also examined if specific antioxidant might help prevent such oxidative cell injury. These studies may then help establish a prophylactic or preventive modality for renal cell injury induced by nephrotoxins. Methods As glycerol has been commonly used for studying acute renal failure in animals, whether it would induce cellular injury was tested in renal proximal tubular OK cells in vitro. Cells were exposed to the varying concentrations of glycerol and cell number/viability was determined in 24 hours. Severity of oxidative stress was assessed by lipid peroxidation assay. Possible effects of glycerol on biochemical parameters were also examined on glyoxalase I activity and heat shock protein 90 using spectrophotometric (enzymatic) assay and Western blot analysis. Results Glycerol (2.5%) was highly cytotoxic to OK cells, inducing 95% cell death in 24 hours. Lipid peroxidation assay indicated that nearly 3-fold greater oxidative stress was exerted by this glycerol. Concurrently, glyoxalase I activity was drastically lost by 75% and heat shock protein 90 was partially degraded following glycerol exposure. However, N-acetylcysteine, a potent glutathione-based antioxidant, was capable of almost completely preventing the glycerol-mediated adverse outcomes, such as cell death, glyoxalase I inactivation, and heat shock protein 90 degradation. Conclusions Glycerol is cytotoxic, capable of inducing specific biochemical alterations such as inactivation of glyoxalase I and degradation of heat shock protein 90, which may reflect a breakdown of the cellular detoxification and defense systems, leading ultimately to OK cell death. Nevertheless, as N-acetylcysteine can provide full cytoprotection against such glycerol toxicity, it could be considered a prophylactic modality for nephrotoxin-induced oxidative renal cell injury and death. Keywords Glycerol; Glyoxalase I; Heat shock protein; N-acetylcysteine; Renal cell injury
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Affiliation(s)
- Andrew I Fishman
- Department of Urology, New York Medical College, Valhalla, New York, USA
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Fishman AI, Johnson B, Alexander B, Won J, Choudhury M, Konno S. Additively enhanced antiproliferative effect of interferon combined with proanthocyanidin on bladder cancer cells. J Cancer 2012; 3:107-12. [PMID: 22393334 PMCID: PMC3293172 DOI: 10.7150/jca.4107] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2012] [Accepted: 01/29/2012] [Indexed: 11/23/2022] Open
Abstract
Although interferon (IFN) has been often used as immunotherapy for bladder cancer, its efficacy is rather unsatisfactory, demanding further improvement. Combination therapy is one of viable options, and grape seed proanthocyanidin (GSP) could be such an agent to be used with IFN because it has been shown to have anticancer activity. We thus investigated whether combination of IFN and GSP might enhance the overall antiproliferative effect on bladder cancer cells in vitro. Human bladder cancer T24 cells were employed and treated with the varying concentrations of recombinant IFN-α2b (0-100,000 IU/ml), GSP (0-100 μg/ml), or their combinations. IFN-α2b alone led to a ~50% growth reduction at 20,000 (20K) IU/ml, which further declined to ~67% at ≥50K IU/ml. Similarly, GSP alone induced a ~35% and ~100% growth reduction at 25 and ≥50 μg/ml, respectively. When IFN-α2b and GSP were then combined, combination of 50K IU/ml IFN-α2b and 25 μg/ml GSP resulted in a drastic >95% growth reduction. Cell cycle analysis indicated that such an enhanced growth inhibition was accompanied by a G1 cell cycle arrest. This was further confirmed by Western blot analysis revealing that expressions of G1-specific cell cycle regulators (CDK2, CDK4, cyclin E and p27/Kip1) were distinctly modulated with such IFN-α2b/GSP treatment. Therefore, these findings support the notion that combination of IFN-α2b and GSP is capable of additively enhancing antiproliferative effect on T24 cells with a G1 cell cycle arrest, implying an adjuvant therapeutic modality for superficial bladder cancer.
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Affiliation(s)
- Andrew I Fishman
- Department of Urology, New York Medical College, Valhalla, New York, USA
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Davalos M, Konno S, Eshghi M, Choudhury M. Oxidative renal cell injury induced by calcium oxalate crystal and renoprotection with antioxidants: a possible role of oxidative stress in nephrolithiasis. J Endourol 2010; 24:339-45. [PMID: 20210657 DOI: 10.1089/end.2009.0205] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
PURPOSE Calcium oxalate (CaOx) is one of the key elements for kidney stone formation, but the exact mechanism needs to be defined. CaOx has been shown to cause renal cell injury through oxidative stress, leading to potential crystal deposition in the kidneys. We thus investigated if CaOx crystal would induce such renal cell injury in vitro and also explored how it would be carried out. MATERIALS AND METHODS Renal tubular epithelial LLC-PK(1) cells were employed, and CaOx monohydrate (COM) was used as CaOx crystal in this study. Cytotoxic effects of COM were assessed on cell viability and biochemical parameters, while protective effect of antioxidants against COM was also examined. RESULTS COM demonstrated its cytotoxicity on LLC-PK(1) cells, exhibiting a approximately 35% cell viability reduction with 500 microg/mL COM in 6 hours. This was presumably attributed to oxidative stress, indicated by lipid peroxidation assay, and N-acetylcysteine (NAC), a potent antioxidant, indeed neutralized such COM cytotoxicity. Although COM also induced inactivation of glutathione-dependent enzymes and partial degradation of heat shock protein 90, these adverse effects were completely prevented with NAC. Moreover, such reduced cell viability with COM was rather associated with apoptosis, evidenced by DNA analysis. CONCLUSION COM is cytotoxic to LLC-PK(1) cells through oxidative stress, leading to the cell viability reduction, adverse effects on biochemical parameters, and, consequently, apoptosis. However, NAC effectively averted such severe cytotoxic effects, sustaining the renal cell integrity. Thus, NAC may provide full renoprotection against COM assault, preventing renal cell injury and ultimate stone formation.
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Affiliation(s)
- Mauricio Davalos
- Department of Urology, New York Medical College, Valhalla, New York 10595, USA.
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Rajamahanty S, Alonzo C, Aynehchi S, Choudhury M, Konno S. Growth inhibition of androgen-responsive prostate cancer cells with brefeldin A targeting cell cycle and androgen receptor. J Biomed Sci 2010; 17:5. [PMID: 20102617 PMCID: PMC2843609 DOI: 10.1186/1423-0127-17-5] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2009] [Accepted: 01/26/2010] [Indexed: 11/28/2022] Open
Abstract
Background Androgen ablation is one of the viable therapeutic options for patients with primary hormone (androgen)-dependent prostate cancer. However, an antibiotic brefeldin A (BFA) has been shown to exhibit the growth inhibitory effect on human cancer cells. We thus investigated if BFA might inhibit proliferation of androgen-responsive prostate cancer LNCaP cells and also explored how it would be carried out, focusing on cell cycle and androgen receptor (AR). Methods Androgen-mediated cellular events in LNCaP cells were induced using 5α-dihydrotestosterone (DHT) as an androgenic mediator. Effects of BFA on non-DHT-stimulated or DHT-stimulated cell growth were assessed. Its growth inhibitory mechanism(s) was further explored; performing cell cycle analysis on a flow cytometer, assessing AR activity by AR binding assay, and analyzing AR protein expression using Western blot analysis. Results DHT (1 nM) was capable of stimulating LNCaP cell growth by ~40% greater than non-stimulated controls, whereas BFA (30 ng/ml) completely inhibited such DHT-stimulated proliferation. Cell cycle analysis showed that this BFA-induced growth inhibition was associated with a ~75% reduction in the cell number in the S phase and a concomitant increase in the G1 cell number, indicating a G1 cell cycle arrest. This was further confirmed by the modulations of specific cell cycle regulators (CDK2, CDK4, cyclin D1, and p21WAF1), revealed by Western blots. In addition, the growth inhibition induced by BFA was accompanied by a profound (~90%) loss in AR activity, which would be presumably attributed to the significantly reduced cellular AR protein level. Conclusions This study demonstrates that BFA has a potent growth inhibitory activity, capable of completely inhibiting DHT (androgen)-stimulated LNCaP proliferation. Such inhibitory action of BFA appears to target cell cycle and AR: BFA led to a G1 cell cycle arrest and the down-regulation of AR activity/expression, possibly accounting for its primary growth inhibitory mechanism. Thus, it is conceivable that BFA may provide a more effective therapeutic modality for patients with hormone-dependent prostate cancer.
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Pyo P, Louie B, Rajamahanty S, Choudhury M, Konno S. Possible immunotherapeutic potentiation with D-fraction in prostate cancer cells. J Hematol Oncol 2008; 1:25. [PMID: 19055833 PMCID: PMC2613393 DOI: 10.1186/1756-8722-1-25] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2008] [Accepted: 12/04/2008] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Prostate cancer remains the most common malignancy among elderly men and the second leading cause of cancer death in the United States. Although several conventional therapies are currently available, they have a low efficacy and the more effective treatment modalities need to be established. Interferons (IFNs) are one of such options known as immunotherapy and demonstrated their antitumor effects on certain cancer types. Yet such antitumor activity should be improved or potentiated to have the satisfactory outcomes. In fact, combination therapy has been proposed as an alternative approach and is being underway in human and animal studies. Accordingly, we studied whether the combination of IFN-alpha and D-fraction (PDF), a bioactive mushroom extract, might potentiate anticancer activity of IFN-alpha in prostate cancer PC-3 cells in vitro. RESULTS Potential effects of recombinant IFN-alpha(2b) (0-100,000 IU/ml), PDF (0-1,000 microg/ml), or their combinations were assessed on the growth of PC-3 cells at 72 h. Cell cycle analysis using a flow cytometer and Western blot analysis were performed to explore antiproliferative mechanism of these agents. The dose-dependent study showed that IFN-alpha(2b) up to 20,000 (20 K) IU/ml had no significant effects, but >60% growth reduction was attained <or=50 K IU/ml. Similarly, PDF showed no effects up to 250 microg/ml but approximately 65% growth reduction was seen at 1,000 microg/ml. When IFN-alpha(2b) and PDF were combined, a relatively low concentration (10 K IU/ml) of IFN-alpha(2b) and PDF (250 microg/ml) resulted in a approximately 65% growth reduction. This was accompanied by a G1 cell cycle arrest, indicated by cell cycle analysis. Western blots also revealed that the G1-specific cell cycle regulators, CDK2, CDK4, CDK6, cyclin D1, and cyclin E, had been significantly (>60%) down-regulated in IFN/PDF-treated cells. CONCLUSION The combination of IFN-alpha(2b) (10 K IU/ml) and PDF (250 microg/ml) is capable of inducing a approximately 65% reduction in PC-3 cell growth. This appears to be due to a synergistic potentiation of two agents, leading to a G1 cell cycle arrest. Thus, it is conceivable that PDF may potentiate IFN-alpha(2b) activity, improving immunotherapy for prostate cancer.
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Affiliation(s)
- Paul Pyo
- Department of Urology, New York Medical College, Valhalla, NY 10595, USA. pyo40@aol
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10
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Brefeldin A activates CHOP promoter at the AARE, ERSE and AP-1 elements. Mol Cell Biochem 2008; 319:203-8. [PMID: 18679584 DOI: 10.1007/s11010-008-9893-3] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2008] [Accepted: 07/24/2008] [Indexed: 10/21/2022]
Abstract
Brefeldin A induces apoptosis in PC-3 and MCF-7 cells at a concentration of 30 ng/ml. RT-PCR analyses showed up-regulation of CHOP/GADD153 and splicing of XBP-1 mRNA in brefeldin A-treated cells. CHOP promoter-luciferase reporter assays demonstrated activation of AARE, ERSE, and AP-1 elements of CHOP promoter by brefeldin A treatment. The activation of these elements was not affected by preincubation of cells with N-acetyl-cysteine (NAC), L: -buthionine-(S,R)-sulfoximine (BSO), and c-Jun N-terminal kinase (JNK) inhibitor (SP600125), suggesting that activation of CHOP promoter by brefeldin A may not involve oxidative stress or JNK signaling pathway. On the other hand, brefeldin A-induced apoptosis was not affected by NAC and BSO pretreatment, but was completely suppressed by JNK inhibitor pretreatment. Our results suggest that although CHOP is up-regulated by brefeldin A, it is not a major mediator of brefeldin A-induced apoptosis.
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Guerra L, Teter K, Lilley BN, Stenerlöw B, Holmes RK, Ploegh HL, Sandvig K, Thelestam M, Frisan T. Cellular internalization of cytolethal distending toxin: a new end to a known pathway. Cell Microbiol 2005; 7:921-34. [PMID: 15953025 DOI: 10.1111/j.1462-5822.2005.00520.x] [Citation(s) in RCA: 93] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
The cytolethal distending toxins (CDTs) are unique in their ability to induce DNA damage, activate checkpoint responses and cause cell cycle arrest or apoptosis in intoxicated cells. However, little is known about their cellular internalization pathway. We demonstrate that binding of the Haemophilus ducreyi CDT (HdCDT) on the plasma membrane of sensitive cells was abolished by cholesterol extraction with methyl-beta-cyclodextrin. The toxin was internalized via the Golgi complex, and retrogradely transported to the endoplasmic reticulum (ER), as assessed by N-linked glycosylation. Further translocation from the ER did not require the ER-associated degradation (ERAD) pathway, and was Derlin-1 independent. The genotoxic activity of HdCDT was dependent on its internalization and its DNase activity, as induction of DNA double-stranded breaks was prevented in Brefeldin A-treated cells and in cells exposed to a catalytically inactive toxin. Our data contribute to a better understanding of the CDT mode of action and highlight two important aspects of the biology of this bacterial toxin family: (i) HdCDT translocation from the ER to the nucleus does not involve the classical pathways followed by other retrogradely transported toxins and (ii) toxin internalization is crucial for execution of its genotoxic activity.
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Affiliation(s)
- Lina Guerra
- Microbiology and Tumorbiology Center, Karolinska Institutet, Stockholm, Sweden
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Fox BM, Vroman JA, Fanwick PE, Cushman M. Preparation and evaluation of sulfide derivatives of the antibiotic brefeldin a as potential prodrug candidates with enhanced aqueous solubilities. J Med Chem 2001; 44:3915-24. [PMID: 11689077 DOI: 10.1021/jm010054z] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Several sulfide (+)-brefeldin A (BFA) analogues were prepared through the Michael addition of various thiols. Many of the sulfides were also oxidized to the corresponding sulfoxide with m-CPBA. The sulfides were designed to act as BFA prodrugs via the metabolic oxidation to the sulfoxide and subsequent syn elimination. Kinetic experiments were used to prove that the syn elimination of the sulfoxides prepared did in fact take place. Five selenide BFA prodrugs were also prepared that are envisioned to act in the same manner as the sulfides. As expected, when oxidation of the selenide to selenoxide was attempted, in situ syn elimination was observed. All of the compounds prepared were evaluated for antiproliferative activity against human cancer cell lines in the National Cancer Institute screen. The sulfoxides were much more potent than either the sulfides or selenides. Especially notable were sulfoxide 21, which possessed a cytotoxicity mean graph midpoint value (MGM) value lower than BFA itself, and sulfoxide 22, which possessed an MGM value slightly less potent than that of BFA. The sulfide analogues were shown to possess increased aqueous solubilty with respect to BFA.
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Affiliation(s)
- B M Fox
- Department of Medicinal Chemistry and Molecular Pharmacology, Purdue University, West Lafayette, Indiana 47907, USA
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13
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Cortes-Bratti X, Chaves-Olarte E, Lagergård T, Thelestam M. Cellular internalization of cytolethal distending toxin from Haemophilus ducreyi. Infect Immun 2000; 68:6903-11. [PMID: 11083812 PMCID: PMC97797 DOI: 10.1128/iai.68.12.6903-6911.2000] [Citation(s) in RCA: 85] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The chancroid bacterium Haemophilus ducreyi produces a toxin (HdCDT) which is a member of the recently discovered family of cytolethal distending toxins (CDTs). These protein toxins prevent the cyclin-dependent kinase cdc2 from being activated, thus blocking the transition of cells from the G(2) phase into mitosis, with the consequent arrest of intoxicated cells in G(2). It is not known whether these toxins act by signaling from the cell surface or intracellularly only. Here we report that HdCDT has to undergo at least internalization before being able to act. Cellular intoxication was inhibited (i) by removal of clathrin coats via K(+) depletion, (ii) by treatment with drugs that inhibit receptor clustering into coated pits, and (iii) in cells genetically manipulated to fail in clathrin-dependent endocytosis. Intoxication was also completely inhibited in cells treated with bafilomycin A1 or nocodazole and in cells incubated at 18 degrees C, i.e., under conditions known to block the fusion of early endosomes with downstream compartments. Moreover, disruption of the Golgi complex by treatment with brefeldin A or ilimaquinone blocked intoxication. In conclusion, our data indicate that HdCDT enters cells via clathrin-coated pits and has to be transported via the Golgi complex in order to intoxicate cells. This is the first member of the family of CDTs for which cellular internalization and some details of the pathway have been demonstrated.
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Affiliation(s)
- X Cortes-Bratti
- Microbiology and Tumorbiology Center, Karolinska Institutet, S-171 77 Stockholm, Sweden
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WALLEN ERIC, SELLERS ROBERTG, PEEHL DONNAM. BREFELDIN A INDUCES p53 -INDEPENDENT APOPTOSIS IN PRIMARY CULTURES OF HUMAN PROSTATIC CANCER CELLS. J Urol 2000. [DOI: 10.1016/s0022-5347(05)67323-5] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- ERIC WALLEN
- From the Department of Urology, Stanford University Medical Center, Stanford, California
| | - ROBERT G. SELLERS
- From the Department of Urology, Stanford University Medical Center, Stanford, California
| | - DONNA M. PEEHL
- From the Department of Urology, Stanford University Medical Center, Stanford, California
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Wallen E, Sellers RG, Peehl DM. Brefeldin A induces p53-independent apoptosis in primary cultures of human prostatic cancer cells. J Urol 2000; 164:836-41. [PMID: 10953164 DOI: 10.1097/00005392-200009010-00058] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
PURPOSE The objective of this study was to investigate growth-inhibitory and apoptotic activity of the experimental antitumor drug, brefeldin A (BFA), on primary cultures of human epithelial cells derived from prostatic adenocarcinomas. MATERIALS AND METHODS Clonal assays were performed to evaluate the effects of BFA on growth of prostatic cancer cell strains. Loss of cell viability in response to BFA was assessed by trypan blue exclusion. Induction of apoptosis by BFA was evaluated by morphologic criteria, electrophoretic assay of DNA fragmentation, and a cell death ELISA. Immunoblots were used to monitor p53 and pRB expression in response to BFA. RESULTS BFA was growth-inhibitory at a half-maximal concentration of 5 ng./ml. (18 nM). Morphological manifestations of apoptosis were evident by 24 hours of treatment. Cell viability declined and the cell death ELISA indicated an 18-fold increase in apoptosis in BFA-treated versus untreated cells at 48 hours. DNA fragmentation was also seen at 48 hours. Levels of p53 were not altered by BFA, but pRB was maintained in a hypophosphorylated state by BFA treatment. CONCLUSIONS BFA is a potent inducer of apoptosis in prostatic cancer cells via a p53-independent mechanism. Cells derived from low-grade as well as high-grade cancers responded similarly to BFA. Since p53-mediated pathways of apoptosis may frequently be abrogated in prostatic cancer cells, agents such as BFA that induce p53-independent cell death may be promising candidates for chemotherapeutic agents.
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Affiliation(s)
- E Wallen
- Department of Urology, Stanford University Medical Center, CA 94305-5118, USA
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Chapman JR, Tazaki H, Mallouh C, Konno S. Brefeldin A-induced apoptosis in prostatic cancer DU-145 cells: a possible p53-independent death pathway. BJU Int 1999; 83:703-8. [PMID: 10233583 DOI: 10.1046/j.1464-410x.1999.00973.x] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
OBJECTIVE To investigate the growth inhibitory mechanism of brefeldin A (BFA), an antiviral antibiotic, in androgen-independent prostatic cancer DU-145 cells. MATERIALS AND METHODS The inhibitory effects of BFA (30 ng/mL) on cell growth were monitored by cell counting and viability tests after specified exposures. Flow cytometry and western immunoblot analysis were performed to examine the effects of BFA on the cell cycle and on specific growth regulators. The possible induction of apoptosis by BFA was further assessed by in situ hybridization (ISH) assay and by qualitative DNA analysis using agarose-gel electrophoresis. RESULTS Cell growth was completely inhibited with BFA (30 ng/mL), accompanied by 40-50% cell death. Cell cycle analysis revealed that this growth inhibition coincided with an 85% reduction in the S-phase cell population. Western blots showed that the expression of cell cycle-dependent kinases (cdk2 and cdk4), cyclin D1 and p53 was significantly reduced, while WAF1 was increased, after BFA treatment. Apoptosis was confirmed by both the ISH assay, which showed the characteristic brownish staining of BFA-treated cells, and by DNA analysis, which revealed the internucleosomal DNA ladder. CONCLUSION BFA-induced growth inhibition in DU-145 cells is primarily due to the modulation of specific G1 cell-cycle regulators, blocking the G1-S phase progression. Such a growth arrest ultimately results in apoptosis, presumably through a p53-independent pathway.
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Affiliation(s)
- J R Chapman
- Department of Urology, New York Medical College, Valhalla, NY 10595, USA
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Liang JY, Fontana JA, Rao JN, Ordonez JV, Dawson MI, Shroot B, Wilber JF, Feng P. Synthetic retinoid CD437 induces S-phase arrest and apoptosis in human prostate cancer cells LNCaP and PC-3. Prostate 1999; 38:228-36. [PMID: 10068347 DOI: 10.1002/(sici)1097-0045(19990215)38:3<228::aid-pros7>3.0.co;2-t] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
BACKGROUND Exposure of prostate carcinoma cell lines to retinoids, which function through the classical retinoic acid nuclear receptor, (RARs) or retinoid X receptors (RXRs), results in minimal cytostatic inhibition of cell proliferation. METHODS Growth inhibition and various regulatory responses were investigated in two human prostate carcinoma cell lines (LNCaP and PC-3) treated with or without a synthetic retinoid, CD 437. RESULTS Incubation of prostate carcinoma cell lines with a novel retinoid CD437 resulted in the marked inhibition of proliferation. LNCaP and PC-3 possessed IC50 values for CD437 of 375 nM and 550 nM, respectively. Incubation with 1 microM CD437 for 24 hr resulted in 100% and 60% inhibition of growth in LNCaP and PC-3 cells, respectively. Simultaneously, cell flow cytometric analyses revealed a dramatic increase of the cell population in S phase, in both LNCaP (from 38.6% up to 86.7%) and PC-3 (27.9% to 55.7%), and a decreased proportion of cells in G2 phase, in LNCaP (from 23.7% down to 1.2%) and PC-3 (14.9% to 2.2%), indicating a significant S-phase arrest. The cell growth inhibition and S-phase arrest in these cells were followed by apoptosis, as revealed by the acquisition of the characteristic cell morphology including the appearance of apoptotic bodies, and further confirmed by cellular DNA fragmentation. CD437-induced-S phase arrest was associated with upregulated mRNA levels of p21waf1/cip1/sdi1 in both LNCaP (p53+/+) and PC-3 (53-/-) cells. CONCLUSIONS CD437 represents a unique retinoid that induces S-phase arrest and apoptosis in both androgen-dependent (LNCaP) and -independent (PC-3) human prostate cancer cells, suggesting a potential role of CD437 in the treatment of human prostate cancer.
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Affiliation(s)
- J Y Liang
- Department of OCBS/Molecular and Cell Biology, University of Maryland Dental School, Baltimore, USA
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18
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CHERRY JAMESP, MORDENTE JOHNA, CHAPMAN JOHNR, CHOUDHURY MUHAMMADS, TAZAKI HIROSHI, MALLOUH CAMILLE, KONNO SENSUKE. ANALYSIS OF CATHEPSIN D FORMS AND THEIR CLINICAL IMPLICATIONS IN HUMAN PROSTATE CANCER. J Urol 1998. [DOI: 10.1016/s0022-5347(01)62300-0] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Affiliation(s)
- JAMES P. CHERRY
- From the Department of Urology, New York Medical College, Valhalla, New York
| | - JOHN A. MORDENTE
- From the Department of Urology, New York Medical College, Valhalla, New York
| | - JOHN R. CHAPMAN
- From the Department of Urology, New York Medical College, Valhalla, New York
| | | | - HIROSHI TAZAKI
- From the Department of Urology, New York Medical College, Valhalla, New York
| | - CAMILLE MALLOUH
- From the Department of Urology, New York Medical College, Valhalla, New York
| | - SENSUKE KONNO
- From the Department of Urology, New York Medical College, Valhalla, New York
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Cherry JP, Mordente JA, Chapman JR, Choudhury MS, Tazaki H, Mallouh C, Konno S. Analysis of cathepsin D forms and their clinical implications in human prostate cancer. J Urol 1998; 160:2223-8. [PMID: 9817374 DOI: 10.1097/00005392-199812010-00090] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
PURPOSE To assess cathepsin D (Cat.D) status in the prostate, we analyzed the different Cat.D forms in human prostate tissues using Western immunoblots. MATERIALS AND METHODS Cell extracts were prepared from prostate tissues (n = 42) obtained from radical prostatectomy, adopting the tissue homogenization method. Expression of the different Cat.D forms was analyzed using Western blots. The catalytic activity of Cat.D was assayed by acid treatment, in which cell extracts were incubated in acidic buffer (pH 3 to 4) at 37C for 1 hour. RESULTS Pathologically confirmed normal (NML), benign prostatic hyperplasia (BPH) and cancer (CAP) specimens all expressed Cat.D, but as two distinct forms. Both NML and BPH predominantly expressed an inactive procathepsin D (Pro.Cat.D), while CAP notably exhibited an active mature Cat.D. The assessment of Cat.D activity, using PSA (prostate specific antigen) as a physiological substrate, showed that such activity was consistently higher in CAP than in NML/BPH specimens. Further studies revealed that the mode of Cat.D activation in CAP specimens appeared to be primarily due to acid-induced autoproteolysis (self-degradation) of mature Cat.D. CONCLUSION This study demonstrates that expression and activity of Cat.D varies among prostate specimens. A greater expression of mature Cat.D with a higher catalytic activity in CAP specimens is the most notable difference from NML/BPH. Therefore, the differential expression/activity of Cat.D forms may be a useful indicator for assessing prostate cancer status.
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Affiliation(s)
- J P Cherry
- Department of Urology, New York Medical College, Valhalla 10595, USA
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Mordente JA, Choudhury MS, Tazaki H, Mallouh C, Konno S. Hydrolysis of androgen receptor by cathepsin D: its biological significance in human prostate cancer. BRITISH JOURNAL OF UROLOGY 1998; 82:431-5. [PMID: 9772884 DOI: 10.1046/j.1464-410x.1998.00760.x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
OBJECTIVE To elicit the biological role of a lysosomal protease, cathepsin D (CatD) in prostate cancer, by investigating its regulatory effect on the androgen receptor (AR) using human prostate cancer LNCaP cells and prostate tissue specimens. MATERIALS AND METHODS Cell extracts were prepared from LNCaP or prostate specimens by cell lysis and tissue homogenization. Proteolytic assays were performed by incubating these extracts in acidic buffer (pH 3-4) at 37 degrees C. The resulting effects on AR and CatD were then analysed using Western immunoblots. RESULTS The Western blots showed that AR was virtually hydrolysed with acid treatment, because endogenous CatD was activated; this activation only occurred at pH 3.2-3.5, but no specific acid appeared to be required. Further analyses suggested that CatD activation could be attributed to acid-induced autoproteolysis of mature CatD. Similar assays were also performed on prostate tissues, including normal and malignant specimens. These studies revealed that CatD-mediated AR hydrolysis was observed only in cancer specimens, while no such hydrolysis occurred in normal specimens. CONCLUSION Endogenous CatD can hydrolyse AR, thereby possibly modulating AR function/metabolism in LNCaP cells, and in cancer specimens. CatD activity also appears to differ significantly between normal and malignant tissue. Thus, CatD may play a pivotal role as a growth modulator in androgen-dependent prostate cancer.
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Affiliation(s)
- J A Mordente
- Department of Urology, New York Medical College, Valhalla, USA
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