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1.
Biosci Trends ; 2020 Mar 13.
Artigo em Inglês | MEDLINE | ID: mdl-32173687

RESUMO

4-anilinoquinazoline-containing inhibitors of the epidermal growth factor receptor (EGFR) are widely used in non-small cell lung cancer patients with mutated EGFR, but they are less effective in multiple myeloma (MM), a fatal malignancy derived from plasma cells. The present study designed a series of novel compounds by conjugating a peroxide bridge to the 4-anilinoquinazoline pharmacophore. Further studies showed that these agents such as 4061 and 4065B displayed potent activity to induce MM cell apoptosis by upregulating pro-apoptotic p53 and Bax while downregulating pro-survival Bcl-2. The mechanistic analysis revealed that both 4061 and 4065B inhibited IGF1-R, AKT and mTOR activation in a concentration dependent manner but had no effects on the expression of their total proteins, suggesting the conjugates of endoperoxide and 4-anilinoquinazoline may exert its anti-myeloma activity by targeting the IGF1-R/AKT/mTOR pathway.

2.
Acta Pharmacol Sin ; 41(3): 394-403, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-31645658

RESUMO

RNF6, a RING-type ubiquitin ligase, has been identified as an oncogene in various cancers but its role in multiple myeloma (MM) remains elusive. In the present study we first showed that the expression levels of RNF6 in MM were significantly elevated compared with the bone marrow cells of healthy donors. Overexpression of RNF6 in LP1 and PRMI-8266 MM cell lines promoted cell proliferation, whereas knockdown of RNF6 led to apoptosis of MM cells. Furthermore, we revealed that RNF6, as a ubiquitin ligase, interacted with glucocorticoid receptor (GR) and induced its K63-linked polyubiquitination. Different from current knowledge, RNF6 increased GR stability at both endogenous and exogenous contexts. Such an action greatly promoted GR transcriptional activity, which was confirmed by luciferase assays and by the increased expression levels of prosurvival genes including Bcl-xL and Mcl-1, two typical downstream genes of the GR pathway. Consistent with these findings, ectopic expression of RNF6 in MM cells conferred resistance to dexamethasone, a typical anti-myeloma agent. In conclusion, we demonstrate that RNF6 promotes MM cell proliferation and survival by inducing atypical polyubiquitination to GR, and RNF6 could be a promising therapeutic target for the treatment of MM.

3.
J Biol Chem ; 295(7): 2084-2096, 2020 Feb 14.
Artigo em Inglês | MEDLINE | ID: mdl-31822558

RESUMO

The Maf proteins, including c-Maf, MafA, and MafB, are critical transcription factors in myelomagenesis. Previous studies demonstrated that Maf proteins are processed by the ubiquitin-proteasome pathway, but the mechanisms remain elusive. This study applied MS to identify MafB ubiquitination-associated proteins and found that the ubiquitin-specific protease USP7 was present in the MafB interactome. Moreover, USP7 also interacted with c-Maf and MafA and blocked their polyubiquitination and degradation. Consistently, knockdown of USP7 resulted in Maf protein degradation along with increased polyubiquitination levels. The action of USP7 thus promoted Maf transcriptional activity as evidenced by luciferase assays and by the up-regulation of the expression of Maf-modulated genes. Furthermore, USP7 was up-regulated in myeloma cells, and it was negatively associated with the survival of myeloma patients. USP7 promoted myeloma cell survival, and when it was inhibited by its specific inhibitor P5091, myeloma cell lines underwent apoptosis. These results therefore demonstrated that USP7 is a deubiquitinase of Maf proteins and promotes MM cell survival in association with Maf stability. Given the significance of USP7 and Maf proteins in myeloma genesis, targeting the USP7/Maf axle is a potential strategy to the precision therapy of MM.

5.
Acta Pharmacol Sin ; 40(12): 1568-1577, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31197245

RESUMO

c-Maf is a critical oncogenic transcription factor that contributes to myelomagenesis. Our previous studies demonstrated that the deubiquitinase USP5 stabilizes c-Maf and promotes myeloma cell proliferation and survival; therefore, the USP5/c-Maf axis could be a potential target for myeloma therapy. As a concept of principle, the present study established a USP5/c-Maf-based luciferase system that was used to screen an FDA-approved drug library. It was found that mebendazole, a typical anthelmintic drug, preferentially induced apoptosis in c-Maf-expressing myeloma cells. Moreover, oral administration of mebendazole delayed the growth of human myeloma xenografts in nude mice but did not show overt toxicity. Further studies showed that the selective antimyeloma activity of mebendazole was associated with the inhibition of the USP5/c-Maf axis. Mebendazole downregulated USP5 expression and disrupted the interaction between USP5 and c-Maf, thus leading to increased levels of c-Maf ubiquitination and subsequent c-Maf degradation. Mebendazole inhibited c-Maf transcriptional activity, as confirmed by both luciferase assays and expression measurements of c-Maf downstream genes. In summary, this study identified mebendazole as a USP5/c-Maf inhibitor that could be developed as a novel antimyeloma agent.

6.
J Biol Chem ; 294(12): 4572-4582, 2019 03 22.
Artigo em Inglês | MEDLINE | ID: mdl-30718275

RESUMO

Chemoresistance is a leading obstacle in effective management of advanced prostate cancer (PCa). A better understanding of the molecular mechanisms involved in PCa chemoresistance could improve treatment of patients with PCa. In the present study, using immune histochemical, chemistry, and precipitation assays with cells from individuals with benign or malignant prostate cancer or established PCa cell lines, we found that the oncogenic transcription factor pre-B cell leukemia homeobox-1 (PBX1) promotes PCa cell proliferation and confers to resistance against common anti-cancer drugs such as doxorubicin and cisplatin. We observed that genetic PBX1 knockdown abrogates this resistance, and further experiments revealed that PBX1 stability was modulated by the ubiquitin-proteasomal pathway. To directly probe the impact of this pathway on PBX1 activity, we screened for PBX1-specific deubiquitinases (Dubs) and found that ubiquitin-specific peptidase 9 X-linked (USP9x) interacted with and stabilized the PBX1 protein by attenuating its Lys-48-linked polyubiquitination. Moreover, the USP9x inhibitor WP1130 markedly induced PBX1 degradation and promoted PCa cell apoptosis. The results in this study indicate that PBX1 confers to PCa chemoresistance and identify USP9x as a Dub of PBX1. We concluded that targeting the USP9x/PBX1 axis could be a potential therapeutic strategy for managing advanced prostate cancer.


Assuntos
Apoptose , Fator de Transcrição 1 de Leucemia de Células Pré-B/metabolismo , Neoplasias da Próstata/patologia , Ubiquitina Tiolesterase/metabolismo , Linhagem Celular Tumoral , Proliferação de Células , Resistencia a Medicamentos Antineoplásicos , Técnicas de Silenciamento de Genes , Humanos , Masculino , Fator de Transcrição 1 de Leucemia de Células Pré-B/genética , Neoplasias da Próstata/enzimologia , Neoplasias da Próstata/metabolismo , Complexo de Endopeptidases do Proteassoma/metabolismo , Proteólise , Ubiquitina/metabolismo
7.
Anticancer Drugs ; 29(10): 995-1003, 2018 11.
Artigo em Inglês | MEDLINE | ID: mdl-30106753

RESUMO

The hedgehog-smoothened (HH/SMO) pathway has been proposed as a potential therapeutic target for hematological malignancies. Our previous studies designed a series of HH inhibitors with novel scaffolds distinctive from vismodegib, the first Food and Drug Administration-approved HH inhibitor for the treatment of basal-cell carcinoma and medulloblastoma. In the present study, we evaluated these HH inhibitors against blood cancers and found that HH78 displayed potent activity in suppressing the HH signaling pathway. HH78 competitively bound to SMO and suppressed the transcriptional activity of GLI by the luciferase reporter gene assay and the measurement of HH/SMO-downregulated genes, including cyclin D2, cyclin E, PTCH1, PTCH2, and GLI. HH78 at low micromolar concentrations induced significant cancer cell apoptosis showed by increased caspase-3 activation, annexin V-staining and downregulated prosurvival proteins, including c-Myc, Bcl-2, Mcl-1, and Bcl-xL. In contrast, vismodegib did not show any effects on these apoptotic events. HH78 also suppressed the activation of the AKT/mTOR pathway, which cross-talks with the HH/SMO pathway. Finally, HH78 inhibited the growth of human leukemia K562 in nude mice xenografts with no overt toxicity. Collectively, the present study identified a novel HH inhibitor with great potential for the treatment of hematological malignancies.


Assuntos
Antineoplásicos/farmacologia , Proteínas Hedgehog/antagonistas & inibidores , Neoplasias Hematológicas/tratamento farmacológico , Receptor Smoothened/antagonistas & inibidores , Anilidas/farmacologia , Animais , Antineoplásicos/administração & dosagem , Antineoplásicos/toxicidade , Apoptose/efeitos dos fármacos , Relação Dose-Resposta a Droga , Regulação para Baixo/genética , Neoplasias Hematológicas/patologia , Humanos , Células K562 , Camundongos , Camundongos Nus , Piridinas/farmacologia , Transdução de Sinais/efeitos dos fármacos , Ensaios Antitumorais Modelo de Xenoenxerto
8.
Environ Sci Pollut Res Int ; 25(28): 28102-28108, 2018 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-30069778

RESUMO

The effects of diatomaceous earth (DE) on the penetrating behavior, tunneling behavior, mortality, and body surface characteristics of the subterranean termite Reticulitermes chinensis were investigated in this study. Our results show that the workers of R. chinensis were able to penetrate 1- and 2-mm layers of dry DE but not 3-mm layers. After treatment with dry DE for 6 h, the mortality of termites reached 100%, which was significantly higher than in the treatment with DE with a 10 and 25% moisture content and treatment with sand of three different moisture contents. The tunneling distances of workers in DE with 10, 25, and 50% moisture contents were all significantly shorter than those in sand with the same moisture contents (10, 25, and 50%), indicating that DE has a good suppressing effect on the tunneling behavior of workers. After treatment with dry DE for different times (1, 3, and 6 h), many DE particles adhered to the bodies of workers, whereas no particles adhered to the body of workers in the case of treatment with dry sand. The treatment with dry DE for 6 h resulted in the death of all workers, which presented conspicuous abdominal shrinkage, whereas workers treated with sand had no significant mortality and no obvious abdominal shrinkage. In summary, we suggest that dry DE has ideal insecticidal activity against the subterranean termite R. chinensis and can be further exploited for controlling termites inside houses.


Assuntos
Terra de Diatomáceas/toxicidade , Inseticidas/toxicidade , Isópteros/efeitos dos fármacos , Animais , Isópteros/fisiologia , Dióxido de Silício
9.
Front Pharmacol ; 9: 673, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-29997504

RESUMO

Saponins are amphipathic glycosides found in traditional Chinese medicines. In the present study, we isolated a panel of saponins from Paris forrestii (Takht.) H. Li, a unique plant found in Tibet and Yunnan provinces, China. By examining their activities in suppressing acute myeloid leukemia (AML) cell proliferation, total saponins from Paris forrestii (TSPf) displayed more potent activity than individual ones. TSPf induced more than 40% AML cell apoptosis and decreased the viability of all leukemia cell lines. TSPf-induced apoptosis was confirmed by both Annexin V staining and caspase-3 activation. In line with these findings, TSPf downregulated pro-survival proteins Mcl-1, Bcl-xL, and Bcl-2 but upregulated the expression of tumor suppressor proteins p53, p27, Bax, and Beclin 1. The AKT/mTOR signaling pathway is frequently overactivated in various AML cells, and TSPf was found to suppress the activation of both AKT and mTOR, but had no effects on their total protein expression. This was further confirmed by the inactivation of 4EBP-1 and p70S6K, two typical downstream signal molecules in the AKT/mTOR pathway. Moreover, TSPf-inactivated AKT/mTOR signaling was found to be associated with downregulated RNF6, a recently identified oncogene in AML. RNF6 activated AKT/mTOR, and consistently, knockdown of RNF6 led to inactivation of the AKT/mTOR pathway. Furthermore, TSPf suppressed the growth of AML xenografts in nude mice models. Oral administration of TSPf almost fully suppressed tumor growth without gross toxicity. Consistent with the findings in cultured cell lines, TSPf also downregulated RNF6 expression along with inactivated AKT/mTOR signaling in tumor tissues. This study thus demonstrated that TSPf displays potent anti-AML activity by suppressing the RNF6/AKT/mTOR pathway. Given its low toxicity, TSPf could be developed for the treatment of AML.

10.
Curr Pharm Des ; 24(15): 1676-1681, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-29807510

RESUMO

BACKGROUND: The HERC family contains six members from HERC1 to HERC6 that are featured with the HECT domains that exerts ubiquitin ligase activity and the RCC1-like domains that are involved in cell cycle regulation. Although identified as early as 1990s, their biological functions are extensively studied in recent years. More and more researches have demonstrated that the HERC ubiquitin ligases are widely engaged in carcinogenesis, however, there lacks a comprehensive and instructive analysis. METHODS: The PubMed database was searched by keywords of individual HERC proteins (such as HERC4) and cancer. The emerging roles of HERC proteins in cancer and the specific mechanisms were collectively analyzed and discussed. RESULTS: HERC proteins belong to the HECT domain-containing ubiquitin ligases that can identify and mediate the ubiquitination of specific substrate proteins. All HERC ubiquitin ligases except HERC6 have been assigned one or more than one ubiquitination substrates. In all of HERCs, HERC1 and HERC2 have been widely studied, in contrast, there are no reported studies yet on protein ubiquitination mediated by HERC6. Dependent on the protein substrates, HERC proteins may act as a tumor suppressor or oncoprotein in specific cancer types. For example, HERC4 is believed to contribute to carcinogenesis of solid tumors such as lung cancer, but it suppresses the proliferation of myeloma cells. CONCLUSION: HERC proteins as ubiquitin ligases are widely involved in various cancers. Targeting at specific HERC proteins could be a strategy for the treatment of certain cancers.


Assuntos
Antineoplásicos/farmacologia , Neoplasias/tratamento farmacológico , Ubiquitina-Proteína Ligases/antagonistas & inibidores , Humanos , Neoplasias/metabolismo , Ubiquitina-Proteína Ligases/metabolismo , Ubiquitinação
11.
J Biol Chem ; 293(16): 5847-5859, 2018 04 20.
Artigo em Inglês | MEDLINE | ID: mdl-29467225

RESUMO

TMEPAI (transmembrane prostate androgen-induced protein, also called prostate transmembrane protein, androgen-induced 1 (PMEPA1)) is a type I transmembrane (TM) protein, but its cellular function is largely unknown. Here, studying factors influencing the stability of c-Maf, a critical transcription factor in multiple myeloma (MM), we found that TMEPAI induced c-Maf degradation. We observed that TMEPAI recruited NEDD4 (neural precursor cell expressed, developmentally down-regulated 4), a WW domain-containing ubiquitin ligase, to c-Maf, leading to its degradation through the proteasomal pathway. Further investigation revealed that TMEPAI interacts with NEDD4 via its conserved PY motifs. Alanine substitution or deletion of these motifs abrogated the TMEPAI complex formation with NEDD4, resulting in failed c-Maf degradation. Functionally, TMEPAI suppressed the transcriptional activity of c-Maf. Of note, increased TMEPAI expression was positively associated with the overall survival of MM patients. Moreover, TMEPAI was down-regulated in MM cells, and re-expression of TMEPAI induced MM cell apoptosis. In conclusion, this study highlights that TMEPAI decreases c-Maf stability by recruiting the ubiquitin ligase NEDD4 to c-Maf for proteasomal degradation. Our findings suggest that the restoration of functional TMEPA1 expression may represent a promising complementary therapeutic strategy for treating patients with MM.


Assuntos
Apoptose , Proteínas de Membrana/metabolismo , Mieloma Múltiplo/metabolismo , Proteólise , Proteínas Proto-Oncogênicas c-maf/metabolismo , Humanos , Mieloma Múltiplo/patologia , Ubiquitina-Proteína Ligases Nedd4/metabolismo , Mapas de Interação de Proteínas , Ubiquitinação
12.
Cell Death Dis ; 8(9): e3058, 2017 09 21.
Artigo em Inglês | MEDLINE | ID: mdl-28933784

RESUMO

The deubiquitinase USP5 stabilizes c-Maf, a key transcription factor in multiple myeloma (MM), but the mechanisms and significance are unclear. In the present study, USP5 was found to interact with c-Maf and prevented it from degradation by decreasing its polyubiquitination level. Specifically, the 308th and 347th lysine residues in c-Maf were critical for USP5-mediated deubiquitination and stability. There are five key domains in the USP5 protein and subsequent studies revealed that the cryptic ZnF domain and the C-box domain interacted with c-Maf but the UBA1/UBA2 domain partly increased its stability. Notably, MafA and MafB are also members of the c-Maf family, however, USP5 failed to deubiquitinate MafA, suggesting its substrate specificity. In the functional studies, USP5 was found to promoted the transcriptional activity of c-Maf. Consistent with the high level of c-Maf protein in MM cells, USP5 was also highly expressed. When USP5 was knocked down, c-Maf underwent degradation. Interestingly, USP5 silence led to apoptosis of MM cells expressing c-Maf but not MM cells lacking c-Maf, indicating c-Maf is a key factor in USP5-mediated MM cell proliferation and survival. Consistent with this finding, WP1130, an inhibitor of several Dubs including USP5, suppressed the transcriptional activity of c-Maf and induced MM cell apoptosis. When c-Maf was overexpressed, WP1130-induced MM cell apoptosis was abolished. Taken together, these findings suggest that USP5 regulates c-Maf stability and MM cell survival. Targeting the USP5/c-Maf axis could be a potential strategy for MM treatment.


Assuntos
Apoptose , Endopeptidases/metabolismo , Mieloma Múltiplo/metabolismo , Mieloma Múltiplo/patologia , Proteólise , Proteínas Proto-Oncogênicas c-maf/metabolismo , Apoptose/genética , Endopeptidases/química , Técnicas de Silenciamento de Genes , Células HEK293 , Humanos , Lisina/metabolismo , Terapia de Alvo Molecular , Mieloma Múltiplo/genética , Poliubiquitina/metabolismo , Ligação Proteica , Domínios Proteicos , Estabilidade Proteica , Relação Estrutura-Atividade , Transcrição Genética , Ubiquitinação
13.
J Pharmacol Sci ; 134(4): 197-202, 2017 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-28779993

RESUMO

S14161 is a pan-Class I PI3K inhibitor that induces blood cancer cell death, but its mechanism is largely unknown. In the present study, we evaluated the role of S14161 in autophagy, an emerging event in cell destination. Multiple myeloma cell lines RPMI-8226, OPM2, KMS11 and leukemia cell line K562 were treated with S14161. The results showed that S14161 induced autophagy as demonstrated by increased LC3-II and decreased p62, which were prevented by autophagy inhibitors including 3-methyladenine and bafilomycin A1. Mechanistic studies showed that S14161 had no effects on Vps34 expression, but increased Beclin 1 and decreased Bcl-2, two major regulators of autophagy. Furthermore, S14161 dissociated the Beclin 1/Bcl-2 complex and enhanced the formation of Beclin 1/Vps34 complex. Moreover, S14161 inhibited the mTORC1 signaling transduction. S14161 downregulated activation of mTOR and its two critical targets 4E-BP1 and p70S6K, suggesting S14161 inhibited protein synthesis. Taken together, these results demonstrated that Class I PI3K regulates autophagy by modulating protein synthesis and the Beclin 1 signaling pathway. This finding helps understanding the roles of PI3K in autophagy and cancer treatment.


Assuntos
Autofagia/efeitos dos fármacos , Proteína Beclina-1/metabolismo , Benzopiranos/farmacologia , Classe III de Fosfatidilinositol 3-Quinases/metabolismo , Neoplasias Hematológicas/patologia , Leucemia/patologia , Mieloma Múltiplo/patologia , Proteína Beclina-1/genética , Linhagem Celular Tumoral , Classe III de Fosfatidilinositol 3-Quinases/genética , Expressão Gênica/efeitos dos fármacos , Humanos , Células K562 , Alvo Mecanístico do Complexo 1 de Rapamicina/metabolismo , Proteínas Associadas aos Microtúbulos/metabolismo , Fosfatidilinositol 3-Quinases/fisiologia , Proteínas de Ligação a RNA/metabolismo , Transdução de Sinais/efeitos dos fármacos
14.
J Hematol Oncol ; 10(1): 132, 2017 07 03.
Artigo em Inglês | MEDLINE | ID: mdl-28673317

RESUMO

BACKGROUND: UBE2O is proposed as a ubiquitin-conjugating enzyme, but its function was largely unknown. METHODS: Mass spectrometry was applied to identify c-Maf ubiquitination-associated proteins. Immunoprecipitation was applied for c-Maf and UBE2O interaction. Immunoblotting was used for Maf protein stability. Luciferase assay was used for c-Maf transcriptional activity. Lentiviral infections were applied for UBE2O function in multiple myeloma (MM) cells. Flow cytometry and nude mice xenografts were applied for MM cell apoptosis and tumor growth assay, respectively. RESULTS: UBE2O was found to interact with c-Maf, a critical transcription factor in MM, by the affinity purification/tandem mass spectrometry assay and co-immunoprecipitation assays. Subsequent studies showed that UBE2O mediated c-Maf polyubiquitination and degradation. Moreover, UBE2O downregulated the transcriptional activity of c-Maf and the expression of cyclin D2, a typical gene modulated by c-Maf. DNA microarray revealed that UBE2O was expressed in normal bone marrow cells but downregulated in MGUS, smoldering MM and MM cells, which was confirmed by RT-PCR in primary MM cells, suggesting its potential role in myeloma pathophysiology. When UBE2O was restored, c-Maf protein in MM cells was significantly decreased and MM cells underwent apoptosis. Furthermore, the human MM xenograft in nude mice showed that re-expression of UBE2O delayed the growth of myeloma xenografts in nude mice in association with c-Maf downregulation and activation of the apoptotic pathway. CONCLUSIONS: UBE2O mediates c-Maf polyubiquitination and degradation, induces MM cell apoptosis, and suppresses myeloma tumor growth, which provides a novel insight in understanding myelomagenesis and UBE2O biology.


Assuntos
Apoptose , Mieloma Múltiplo/metabolismo , Proteínas Proto-Oncogênicas c-maf/metabolismo , Enzimas de Conjugação de Ubiquitina/metabolismo , Ubiquitinação , Animais , Linhagem Celular Tumoral , Células Cultivadas , Células HEK293 , Humanos , Camundongos Nus , Mieloma Múltiplo/patologia , Mapas de Interação de Proteínas , Estabilidade Proteica , Proteínas Proto-Oncogênicas c-maf/análise , Enzimas de Conjugação de Ubiquitina/análise
15.
Anticancer Drugs ; 28(4): 376-383, 2017 04.
Artigo em Inglês | MEDLINE | ID: mdl-28301380

RESUMO

The aim of this study was to identify the most potent quinoline-based anti-infectives for the treatment of multiple myeloma (MM) and to understand the molecular mechanisms. A small-scale screen against a panel of marketed quinoline-based drugs was performed in MM cell lines. Cell apoptosis was examined by flow cytometry. Anti-MM activity was also evaluated in nude mice. Western blotting was performed to investigate mechanisms. Nitroxoline (NXQ) was the most effective in suppressing MM cell proliferation. NXQ induced more than 40% MM cell apoptosis within 24 h and potentiated anti-MM activities of current major drugs including doxorubicin and lenalidomide. This finding was shown by activation of caspase-3, a major executive apoptotic enzyme, and by inactivation of PARP, a major enzyme in DNA damage repair. NXQ also suppressed prosurvival proteins Bcl-xL and Mcl-1. Moreover, NXQ suppressed the growth of myeloma xenografts in nude mice models. In the mechanistic study, NXQ was found to downregulate TRIM25, a highly expressed ubiquitin ligase in MM. Notably, NXQ upregulated tumor suppressor p53, but not PTEN. Furthermore, overexpression of TRIM25 decreased p53 protein. This study indicated that the long-term use of anti-infective NXQ has potential for MM treatment by targeting the TRIM25/p53 axle.


Assuntos
Mieloma Múltiplo/tratamento farmacológico , Nitroquinolinas/farmacologia , Fatores de Transcrição/metabolismo , Proteínas com Motivo Tripartido/metabolismo , Proteína Supressora de Tumor p53/metabolismo , Ubiquitina-Proteína Ligases/metabolismo , Células A549 , Animais , Linhagem Celular Tumoral , Ensaios de Seleção de Medicamentos Antitumorais , Feminino , Humanos , Camundongos , Camundongos Nus , Terapia de Alvo Molecular , Mieloma Múltiplo/genética , Mieloma Múltiplo/metabolismo , Uso Off-Label , Distribuição Aleatória , Fatores de Transcrição/biossíntese , Fatores de Transcrição/genética , Proteínas com Motivo Tripartido/biossíntese , Proteínas com Motivo Tripartido/genética , Ubiquitina-Proteína Ligases/biossíntese , Ubiquitina-Proteína Ligases/genética , Ensaios Antitumorais Modelo de Xenoenxerto
16.
Acta Pharmacol Sin ; 38(5): 651-659, 2017 May.
Artigo em Inglês | MEDLINE | ID: mdl-28260800

RESUMO

The signal transducer and activator of transcription 3 (STAT3) plays a critical role in platelet functions. This study sought to understand the effects of the STAT3 inhibitor SC99 on platelet activation and aggregation. Immunoblotting assays were applied to measure the effects of SC99 on the STAT3 signaling pathway. A ChronoLog aggregometer was used to evaluate platelet aggregation. A flow cytometer was used to evaluate P-selectin expression in the presence of SC99. AlamarBlue and Annexin-V staining were used to evaluate platelet viability and apoptosis, respectively. A fluorescence microscope was applied to analyze platelet spreading. SC99 inhibited the phosphorylation of JAK2 and STAT3 in human platelets but had no effects on the phosphorylation of AKT, p65 or Src, all of which are involved in platelet activation. Further studies revealed that SC99 inhibited human platelet aggregation induced by collagen and thrombin in a dose-dependent manner. SC99 inhibited thrombin-induced P-selectin expression and fibrinogen binding to single platelets. Moreover, SC99 inhibited platelet spreading on fibrinogen and clot retraction mediated by outside-in signaling. SC99 inhibited platelet aggregation in mice but it did not significantly prolong the bleeding time. Taken together, the present study revealed that SC99 inhibited platelet activation and aggregation as a STAT3 inhibitor. This agent can be developed as a promising treatment for thrombotic disorders.


Assuntos
Hidrazonas/farmacologia , Ativação Plaquetária/efeitos dos fármacos , Inibidores da Agregação de Plaquetas/farmacologia , Agregação Plaquetária/efeitos dos fármacos , Fator de Transcrição STAT3/antagonistas & inibidores , Animais , Tempo de Sangramento , Retração do Coágulo/efeitos dos fármacos , Humanos , Hidrazonas/toxicidade , Camundongos Endogâmicos C57BL , Inibidores da Agregação de Plaquetas/toxicidade , Transdução de Sinais
17.
Oncotarget ; 8(12): 20103-20112, 2017 Mar 21.
Artigo em Inglês | MEDLINE | ID: mdl-28223545

RESUMO

Ring finger protein 6 (RNF6) is a key oncogene in both prostate cancer and leukemia, but its role is elusive in breast cancer. In the present study, we found that RNF6 was overexpressed in more than 70% of breast cancer tissues and it was associated with overall survival. RNF6 increased breast cancer cell proliferation, migration and reduced cell sensitivity to doxorubicin. Further studies showed that RNF6 was closely associated with increased expression of estrogen receptor, a critical factor in the development of breast cancers. RNF6 was found to induce ERα expression and increased its stability. In doxorubicin-resistant breast cancer cells, RNF6 was found to be elevated in association with increased ERα and anti-apoptotic Bcl-xL, but not pro-apoptotic Bim-1. In consistence with this finding, overexpression of ERα led to increased Bcl-xL but had no effects on Bim-1. Therefore, this study demonstrated that there exists an RNF6/ERα/Bcl-xL axle in breast cancer which promotes cancer cell proliferation and survival. Targeting the RNF6/ERα/Bcl-xL axle could be a promising strategy in the treatment of breast cancer.


Assuntos
Biomarcadores Tumorais/metabolismo , Neoplasias da Mama/patologia , Carcinoma Ductal de Mama/secundário , Proliferação de Células , Proteínas de Ligação a DNA/metabolismo , Receptor alfa de Estrogênio/metabolismo , Proteína bcl-X/metabolismo , Apoptose , Biomarcadores Tumorais/genética , Neoplasias da Mama/genética , Neoplasias da Mama/metabolismo , Carcinoma Ductal de Mama/genética , Carcinoma Ductal de Mama/metabolismo , Estudos de Casos e Controles , Proteínas de Ligação a DNA/genética , Receptor alfa de Estrogênio/genética , Feminino , Seguimentos , Humanos , Metástase Linfática , Pessoa de Meia-Idade , Gradação de Tumores , Invasividade Neoplásica , Estadiamento de Neoplasias , Prognóstico , Taxa de Sobrevida , Células Tumorais Cultivadas , Proteína bcl-X/genética
18.
Oncotarget ; 7(46): 75539-75550, 2016 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-27705908

RESUMO

The activated JAK2-STAT3 signaling pathway is a high risk factor for multiple myeloma (MM), a fatal malignancy of plasma cells. In the present study, SC09, a potential inhibitor of cholesterol absorption, was identified in a STAT3-targeted drug screen. SC09 suppressed the activation of STAT3 in a time-course and concentration-dependent manner but did not affect its family members STAT1 and STAT5. SC09 inhibited STAT3 transcriptional activity and downregulated the expression of STAT3-regulated genes. Further studies showed that SC09 selectively inhibited JAK2 activation but not other kinases including c-Src, ERK, p38 and mTOR that are all associated with STAT3 activation. Moreover, SC09 obviously induced MM cell death in vitro and delayed MM tumor growth in vivo. SC09-induced MM cell death was dependent on the endogenous STAT3 status, and this effect could be attenuated by enforced expression of STAT3. All the results collectively indicated that SC09 blocks the JAK2-STAT3 signaling thus displaying anti-MM activity. Given its well tolerance and anti-MM potency, SC09 is credited for further investigation as a promising drug for MM treatment.


Assuntos
Antineoplásicos/farmacologia , Colesterol/metabolismo , Janus Quinase 2/metabolismo , Metabolismo dos Lipídeos/efeitos dos fármacos , Mieloma Múltiplo/metabolismo , Fator de Transcrição STAT3/metabolismo , Transdução de Sinais/efeitos dos fármacos , Animais , Antineoplásicos/química , Apoptose/efeitos dos fármacos , Linhagem Celular Tumoral , Modelos Animais de Doenças , Doxorrubicina/farmacologia , Humanos , Janus Quinase 2/química , Camundongos , Camundongos Nus , Mieloma Múltiplo/tratamento farmacológico , Mieloma Múltiplo/genética , Fosforilação , Fator de Transcrição STAT3/genética , Ativação Transcricional/efeitos dos fármacos
19.
Oncotarget ; 7(43): 70143-70151, 2016 10 25.
Artigo em Inglês | MEDLINE | ID: mdl-27659523

RESUMO

Interferon-stimulated gene 15 (ISG15) is an important cytokine that has been reported in carcinogenesis. However, we found that ISG15 and de-ISGylase USP18 were induced by several anti-cancer agents, which was confirmed by both RT-PCR and immunoblotting assays. Further studies demonstrated that ectopic ISG15 and USP18 inhibited proliferation of myeloma, leukemia and cervical cancer cells. More importantly, ISG15 and USP18 induced cancer cell apoptosis. This finding was confirmed in a cervical xenograft model in which cervical cancer growth was suppressed by lentiviral ISG15. In the mechanistic study, ISG15 was found to disrupt the NF-κB signaling pathway by downregulating the expression of IKKß and p65, phosphorylation of p65 and IκBα. Consistent with this finding, ISG15 suppressed the expression of NF-κB recognition element-driving luciferase and decreased the transcription of XIAP and Mcl-1, two typical genes regulated by NF-κB. Therefore, the present study demonstrated that ISG15 induces cancer cell apoptosis by disrupting the NF-κB signaling pathway. This study highlighted a novel role of ISG15 in tumor suppression.


Assuntos
Apoptose , Citocinas/fisiologia , NF-kappa B/fisiologia , Neoplasias/patologia , Transdução de Sinais/fisiologia , Proteínas Supressoras de Tumor/fisiologia , Ubiquitinas/fisiologia , Animais , Linhagem Celular Tumoral , Proliferação de Células , Clioquinol/farmacologia , Endopeptidases/fisiologia , Feminino , Humanos , Mefloquina/farmacologia , Camundongos , Camundongos Endogâmicos BALB C
20.
J Biol Chem ; 291(18): 9617-28, 2016 Apr 29.
Artigo em Inglês | MEDLINE | ID: mdl-26971355

RESUMO

RNF6 is a little-studied ring finger protein. In the present study, we found that RNF6 was overexpressed in various leukemia cells and that it accelerated leukemia cell proliferation, whereas knockdown of RNF6 delayed tumor growth in xenografts. To find out the mechanism of RNF6 overexpression in leukemia, we designed a series of truncated constructs of RNF6 regulatory regions in the luciferase reporter system. The results revealed that the region between -144 and -99 upstream of the RNF6 transcription start site was critical and that this region contained a PBX1 recognition element (PRE). PBX1 modulated RNF6 expression by binding to the specific PRE. When PRE was mutated, RNF6 transcription was completely abolished. Further studies showed that PBX1 collaborated with PREP1 but not MEIS1 to modulate RNF6 expression. Moreover, RNF6 expression could be suppressed by doxorubicin, a major anti-leukemia agent, via down-regulating PBX1. This study thus suggests that RNF6 overexpression in leukemia is under the direction of PBX1 and that the PBX1/RNF6 axis can be developed as a novel therapeutic target of leukemia.


Assuntos
Proteínas de Ligação a DNA/biossíntese , Proteínas de Ligação a DNA/metabolismo , Regulação Leucêmica da Expressão Gênica , Leucemia/metabolismo , Proteínas Proto-Oncogênicas/biossíntese , Elementos de Resposta , Animais , Proteínas de Ligação a DNA/genética , Doxorrubicina/farmacologia , Células HL-60 , Xenoenxertos , Proteínas de Homeodomínio/genética , Proteínas de Homeodomínio/metabolismo , Humanos , Células Jurkat , Células K562 , Leucemia/tratamento farmacológico , Leucemia/genética , Leucemia/patologia , Camundongos , Proteína Meis1 , Proteínas de Neoplasias/genética , Proteínas de Neoplasias/metabolismo , Transplante de Neoplasias , Fator de Transcrição 1 de Leucemia de Células Pré-B , Proteínas Proto-Oncogênicas/genética
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