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Colorectal cancer (CRC) is the second most common cancer in the world and death from CRC accounts for 8% of all cancer deaths both in men and women in the United States. CRC is life-threatening disease due to therapy resistant cancerous cells. The exact mechanisms of cell growth, survival, metastasis and inter & intracellular signaling pathways involved in CRC is still a significant challenge. Hence, investigating the signaling pathways that lead to colon carcinogenesis may give insight into the therapeutic target. In this study, the role of atypical Protein Kinase C (aPKC) on CRC was investigated by using two inhibitors of that protein class: 1) ζ-Stat (8-hydroxynaphthalene-1,3,6-trisulfonic acid) is a specific inhibitor of PKC-ζ and 2) ICA-I 5-amino-1-(2,3-dihydroxy-4-hydroxymethyl)cyclopentyl)-1H-imidazole-4-carboxamide) is a specific inhibitor of PKC-ι. The cell lines tested were CCD18CO normal colon epithelial and LOVO metastatic CRC cells. The inhibition of aPKCs did not bring any significant toxicity on CCD18CO normal colon cell line. Although PKC-ι is an oncogene in many cancers, we found the overexpression of PKC-ζ and its direct association with Rac1. Our findings suggest that the PKC-ζ may be responsible for the abnormal growth, proliferation, and migration of metastatic LOVO colon cancer cells via PKC-ζ/Rac1/Pak1/ß-Catenin pathway. These results suggest the possibility of utilizing PKC-ζ inhibitor to block CRC cells growth, proliferation, and metastasis.
Assuntos
Carcinogênese/metabolismo , Carcinogênese/patologia , Neoplasias Colorretais/metabolismo , Neoplasias Colorretais/patologia , Proteína Quinase C/metabolismo , beta Catenina/metabolismo , Quinases Ativadas por p21/metabolismo , Proteínas rac1 de Ligação ao GTP/metabolismo , Apoptose/efeitos dos fármacos , Linhagem Celular Tumoral , Núcleo Celular/efeitos dos fármacos , Núcleo Celular/metabolismo , Proliferação de Células/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Colo/patologia , Técnicas de Silenciamento de Genes , Humanos , Imidazóis/química , Imidazóis/farmacologia , Modelos Biológicos , Metástase Neoplásica , Organofosfatos/química , Organofosfatos/farmacologia , Fosforilação/efeitos dos fármacos , Fosfosserina/metabolismo , Inibidores de Proteínas Quinases/química , Inibidores de Proteínas Quinases/farmacologia , Transporte Proteico/efeitos dos fármacosRESUMO
Protein kinase C-iota (PKC-ι) is an oncogene overexpressed in many cancer cells including prostate, breast, ovarian, melanoma, and glioma. Previous in-vitro studies have shown that 5-amino-1-((1R,2S,3S,4R)-2,3-dihydroxy-4-methylcyclopentyl)-1H-imidazole-4-carboxamide (ICA-1s), a PKC-ι specific inhibitor, is effective against some cancer cell lines by decreasing cell growth and inducing apoptosis. To assess ICA-1s as a possible therapeutic, in-vivo studies using a murine model were performed. ICA-1s was tested for stability in blood serum and results demonstrated that ICA-1s was stable in human plasma at 25 and 37°C over a course of 2 h. Toxicity of ICA-1s was tested for both acute and subacute exposure. The acute exposure showed patient surviving after 48 h of doses ranging from 5 to 5000 mg/kg. Subacute tests exposed the patients to 14 days of treatment and were followed by serum and tissue collection. Aspartate aminotransferase, alkaline phosphatase, γ-glutamyl transpeptidase, troponin, and C-reactive protein serum levels were measured to assess organ function. ICA-1s in plasma serum was measured over the course of 24 h for both oral and intravenous treatments. Heart, liver, kidney, and brain tissues were analyzed for accumulation of ICA-1s. Finally, athymic nude mice were xenografted with DU-145 prostate cancer cells. After tumors reached ~0.2 cm, they were either treated with ICA-1s or left as control and measured for 30 days or until the tumor reached 2 cm. Results showed tumors in treated mice grew at almost half the rate as untreated tumors, showing a significant reduction in growth. In conclusion, ICA-1s is stable, shows low toxicity, and is a potential therapeutic for prostate carcinoma tumors.
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Imidazóis/farmacologia , Isoenzimas/antagonistas & inibidores , Neoplasias da Próstata/tratamento farmacológico , Proteína Quinase C/antagonistas & inibidores , Animais , Linhagem Celular Tumoral , Humanos , Imidazóis/sangue , Masculino , Camundongos , Camundongos Nus , Neoplasias da Próstata/sangue , Neoplasias da Próstata/enzimologia , Inibidores de Proteínas Quinases/sangue , Inibidores de Proteínas Quinases/farmacologia , Ensaios Antitumorais Modelo de XenoenxertoRESUMO
Coordination-driven self-assembly is an effective synthetic tool for the construction of spatially and electronically tunable supramolecular coordination complexes (SCCs), which are useful in various applications. Herein, we report the synthesis of a two-dimensional discrete metalla-rectangle [(η6-p-cymene)4Ru4(C6H2O4)2(2)2](CF3SO3)4 (3) by the reaction of a dinuclear half-sandwich ruthenium (II) complex [Ru2(η6-p-cymene)2(C6H2O4)Cl2] (1) and bis-pyridyl amide linker (2) in the presence of AgO3SCF3. This cationic ruthenium metalla-rectangle (3) has been isolated as its triflate salt and characterized by analytical techniques including elemental analysis, Fourier-transform infrared spectroscopy (FT-IR), proton nuclear magnetic resonance spectroscopy (1H-NMR), carbon nuclear magnetic resonance spectroscopy (13C-NMR), 1H-1H correlation spectroscopy (COSY), 1H-1H nuclear Overhauser effect spectroscopy (NOESY), diffusion ordered spectroscopy (DOSY), and high-resolution electrospray ionization mass spectrometry (HR-ESI-MS). Significantly, the 2D cationic ruthenium metalla-rectangle showed better anticancer activity towards three different cell lines (A549, Caki-1 and Lovo) as compared with the parent ruthenium complex (1) and the commercially used drug, cisplatin.
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Antineoplásicos/química , Antineoplásicos/farmacologia , Complexos de Coordenação/química , Complexos de Coordenação/farmacologia , Rutênio , Antineoplásicos/síntese química , Linhagem Celular Tumoral , Sobrevivência Celular/efeitos dos fármacos , Cisplatino/farmacologia , Complexos de Coordenação/síntese química , Humanos , Estrutura Molecular , Rutênio/química , Espectrometria de Massas por Ionização por ElectrosprayRESUMO
Glioblastoma is a highly aggressive type of brain cancer which currently has limited options for treatment. It is imperative to develop combination therapies that could cause apoptosis in glioblastoma. The aim of this study was to characterize the affect of modified ICA-1, a PKC-iota inhibitor, on the growth pattern of various glioblastoma cell lines. T98G and U87 glioblastoma cells were treated with ICA-1 alone and the absolute cell numbers of each group were determined for cell growth expansion analysis, cell viability analysis, and cell death analysis. Low dose ICA-1 treatment alone significantly inhibited cell growth expansion of high density glioblastoma cells without inducing cell death. However, the high dose ICA-1 treatment regimen provided significant apoptosis for glioblastoma cells. Furthermore, this study was conducted to use a two layer molecular level approach for treating glioblastoma cells with ICA-1 plus an apoptosis agent, tumor-necrosis factor-related apoptosis-inducing ligand (TRAIL), to induce apoptosis in such chemo-refractory cancer cells. Following ICA-1 plus TRAIL treatment, apoptosis was detected in glioblastoma cells via the TUNEL assay and via flow cytometric analysis using Annexin-V FITC/PI. This study offers the first evidence for ICA-1 alone to inhibit glioblastoma cell proliferation as well as the novel combination of ICA-1 with TRAIL to cause robust apoptosis in a caspase-3 mediated mechanism. Furthermore, ICA-1 plus TRAIL simultaneously modulates down-regulation of PKC-iota and c-Jun.
Assuntos
Neoplasias Encefálicas/tratamento farmacológico , Glioblastoma/tratamento farmacológico , Isoenzimas/antagonistas & inibidores , Proteína Quinase C/antagonistas & inibidores , Transdução de Sinais , Ligante Indutor de Apoptose Relacionado a TNF/uso terapêutico , Apoptose/efeitos dos fármacos , Neoplasias Encefálicas/enzimologia , Neoplasias Encefálicas/patologia , Caspase 3/metabolismo , Linhagem Celular Tumoral , Glioblastoma/enzimologia , Glioblastoma/patologia , Humanos , Imidazóis/farmacologia , Isoenzimas/metabolismo , Organofosfatos/farmacologia , Proteína Quinase C/metabolismo , Proteínas Proto-Oncogênicas c-jun/metabolismo , Ligante Indutor de Apoptose Relacionado a TNF/farmacologiaRESUMO
Background: Renal Cell Carcinoma (RCC) is the most common type of kidney cancer (85%). 75% of the RCC cases involve conventional clear cell RCC (ccRCC). Approximately, 39% of late-stage patients (stage IV) are treated with chemotherapeutic agents. Phosphatidylinositol-3-kinase (PI3K) and Mitogen-Activated Protein Kinase Kinase (MEK)/extracellular signal-regulated kinase (ERK1/2) pathways are frequently activated in RCC. In addition, atypical PKCs (PKC-ί and PKC ζ) are overexpressed in most cancer cells, and they play a central role in tumor progression and the metastasis of different types of cancers. Our goal is to establish the role of aPKCs in the regulation of multiple key activated pathways in ccRCC. In this study, we also established a novel therapeutic regimen for dual inhibition of key activated pathways. Method: In this study, 786-0 and Caki-1 cells were studied and subjected to cell viability assay, western blot analysis, scratch & wound healing assay, transwell invasion assay, immunofluorescence, immunoprecipitation, flow cytometry, and quantitative real-time polymerase chain reaction. We used combination of PI3K inhibitor- Alpelisib (BYL719) and ICA-1 (a PKC-ι-specific 5-amino-1-2,3-dihydroxy-4-(methylcyclopentyl)-1H-imidazole-4-carboxamide). In addition to drug treatment, small interfering RNA (siRNA) technology was used to further confirm the experimental outcome of the drug treatment. Results: Our results suggest that treatment of ccRCC cells with a combination of ICA-1 (aPKC inhibitor) and BYL719 (PI3K inhibitor) downregulates PKC-ί and causes downstream inhibition of c-Myc. Inhibition of the PKCί also reduces activation of MEK/ERK1/2. It is observed that treatment with ICA-1 disrupts the level of the aPKC-Akt1 association. ICA-1 treatment also shows a reduced level of association between aPKC and c-Myc. The inhibition of aPKCs and downstream effector proteins by combination therapy is more pronounced compared to a single therapy. These effects contribute to reduced cell growth, and eventually, the induction of apoptosis. The decreased level of N-cadherin, p-vimentin, and vimentin and the increased level of E-cadherin confirm reduced malignancy. Conclusion: Therefore, implementing a combination of Alpelisib and a PKC-ι inhibitor is an effective approach to reducing cell proliferation, and invasion that eventually induces apoptosis and may be considered as a potential therapeutic option in ccRCC.
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The objective of this research was to study the potential function of protein kinase C (PKC)-ι in cell cycle progression and proliferation in glioblastoma. PKC-ι is highly overexpressed in human glioma and benign and malignant meningioma; however, little is understood about its role in regulating cell proliferation of glioblastoma. Several upstream molecular aberrations and/or loss of PTEN have been implicated to constitutively activate the phosphatidylinositol (PI) (3)-kinase pathway. PKC-ι is a targeted mediator in the PI (3)-kinase signal transduction repertoire. Results showed that PKC-ι was highly activated and overexpressed in glioma cells. PKC-ι directly associated and phosphorylated Cdk7 at T170 in a cell cycle-dependent manner, phosphorylating its downstream target, cdk2 at T160. Cdk2 has a major role in inducing G(1)-S phase progression of cells. Purified PKC-ι phosphorylated both endogenous and exogenous Cdk7. PKC-ι downregulation reduced Cdk7 and cdk2 phosphorylation following PI (3)-kinase inhibition, phosphotidylinositol-dependent kinase 1 knockdown as well as PKC-ι silencing (by siRNA treatment). It also diminished cdk2 activity. PKC-ι knockdown inhibited overall proliferation rates and induced apoptosis in glioma cells. These findings suggest that glioma cells may be proliferating through a novel PI (3)-kinase-/PKC-ι/Cdk7/cdk2-mediated pathway.
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Neoplasias Encefálicas/enzimologia , Quinases Ciclina-Dependentes/metabolismo , Glioblastoma/enzimologia , Isoenzimas/fisiologia , Fosfatidilinositol 3-Quinases/fisiologia , Proteína Quinase C/fisiologia , Transdução de Sinais/fisiologia , Apoptose , Neoplasias Encefálicas/patologia , Ciclo Celular , Linhagem Celular Tumoral , Quinase 2 Dependente de Ciclina/metabolismo , Glioblastoma/patologia , Humanos , Fosforilação , Proteínas Serina-Treonina Quinases/fisiologia , Piruvato Desidrogenase Quinase de Transferência de Acetil , Quinase Ativadora de Quinase Dependente de CiclinaRESUMO
Current treatment options of glioblastoma include chemotherapy and limited surgical resection. Temozolomide (TMZ) is the current therapeutic choice for chemotherapy. Still, it has severe limitations due to the development of resistance that occurs by genetic modification and constitutive activation of several cell signaling pathways. Therefore, it is essential to develop combination therapy of TMZ with other novel compounds to prevent the development of chemo-resistance. In this study, we used two inhibitors; ICA, an inhibitor of PKC-ι and ζ-Stat, an inhibitor of PKC-ζ. T98G and U87MG glioblastoma cells were treated with either ICA or ζ-stat or TMZ monotherapies, as well as TMZ were combined with either ICA or ζ-stat for five consecutive days. Our in vitro results exhibited that ICA when combined with TMZ, significantly decreased the viability of cancerous cells compared with untreated or TMZ or ICA monotherapies. Additionally, glioblastoma cells were remarkably undergoing apoptosis against the combination treatment of TMZ and ICA nucleotide compared with untreated control cells, as suggested by our Annexin-V/PI flow cytometric analysis. Moreover, the combination of TMZ and ICA also decreased the invasion of glioblastoma cell lines by acting on FAK/Paxillin pathway, as evidenced by scratch assay, transwell invasion assay, Western blot and immunoprecipitation analysis. Furthermore, our in vivo data presented that the combination of ICA and TMZ also reduced glioblastoma tumor growth and volume in mice. These data suggest that atypical PKCs, particularly PKC-ι might be an important therapeutic target as adjuvant therapy in the treatment of glioblastoma.
Assuntos
Isoenzimas/metabolismo , Proteína Quinase C/metabolismo , Inibidores de Proteínas Quinases/farmacologia , Transdução de Sinais/efeitos dos fármacos , Temozolomida/farmacologia , Citoesqueleto de Actina/efeitos dos fármacos , Animais , Apoptose/efeitos dos fármacos , Linhagem Celular Tumoral , Movimento Celular/efeitos dos fármacos , Quimioterapia Combinada , Quinase 1 de Adesão Focal/metabolismo , Glioblastoma/tratamento farmacológico , Glioblastoma/patologia , Humanos , Isoenzimas/antagonistas & inibidores , Isoenzimas/genética , Camundongos , Camundongos Nus , Proteína Quinase C/antagonistas & inibidores , Proteína Quinase C/genética , Inibidores de Proteínas Quinases/uso terapêutico , Interferência de RNA , RNA Interferente Pequeno/metabolismo , Temozolomida/uso terapêutico , Transplante HeterólogoRESUMO
Diet-induced obesity, the metabolic syndrome, type 2 diabetes (DIO/MetS/T2DM), and their adverse sequelae have reached pandemic levels. In mice, DIO/MetS/T2DM initiation involves diet-dependent increases in lipids that activate hepatic atypical PKC (aPKC) and thereby increase lipogenic enzymes and proinflammatory cytokines. These or other hepatic aberrations, via adverse liver-to-muscle cross talk, rapidly impair postreceptor insulin signaling to glucose transport in muscle. The ensuing hyperinsulinemia further activates hepatic aPKC, which first blocks the ability of Akt to suppress gluconeogenic enzyme expression, and later impairs Akt activation, further increasing hepatic glucose production. Recent findings suggest that hepatic aPKC also increases a proteolytic enzyme that degrades insulin receptors. Fortunately, all hepatic aberrations and muscle impairments are prevented/reversed by inhibition or deficiency of hepatic aPKC. But, in the absence of treatment, hyperinsulinemia induces adverse events, some by using "spare receptors" to bypass receptor defects. Thus, in brain, hyperinsulinemia increases Aß-plaque precursors and Alzheimer risk; in kidney, hyperinsulinemia activates the renin-angiotensin-adrenal axis, thus increasing vasoconstriction, sodium retention, and cardiovascular risk; and in liver, hyperinsulinemia increases lipogenesis, obesity, hepatosteatosis, hyperlipidemia, and cardiovascular risk. In summary, increases in hepatic aPKC are critically required for development of DIO/MetS/T2DM and its adverse sequelae, and therapeutic approaches that limit hepatic aPKC may be particularly effective.
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Atypical protein kinase C (aPKC) are involved in progression of many human cancers. Vimentin is expressed during epithelial to mesenchymal transition (EMT). Molecular dynamics of Vimentin intermediate filaments (VIFs) play a key role in metastasis. This article is an effort to provide thorough understanding of the relationship between Vimentin and aPKCs . We demonstrate that diminution of aPKCs lead to attenuate prostate cellular metastasis through the downregulation of Vimentin expression. siRNA knocked-down SNAIL1 and PRRX1 reduce aPKC activity along with Vimentin. Results suggest that aPKCs target multiple activation sites (Ser33/39/56) on Vimentin and therefore is essential for VIF dynamics regulation during the metastasis of prostate cancer cells. Understanding the aPKC related molecular mechanisms may provide a novel therapeutic path for prostate carcinoma.
Assuntos
Transição Epitelial-Mesenquimal , Neoplasias da Próstata , Linhagem Celular Tumoral , Movimento Celular , Transição Epitelial-Mesenquimal/genética , Proteínas de Homeodomínio , Humanos , Filamentos Intermediários , Masculino , Neoplasias da Próstata/genética , Vimentina/genéticaRESUMO
PURPOSE: The options for treating lung cancers are limited, as diagnosis typically occurs during the late stages of the disease. There is a dire need to develop aPKC (atypical Protein Kinase C) inhibitors due to aPKC overexpression and contributions to lung cancer malignancies. In this study, we investigate the role of atypical PKCs (aPKCs) in cell proliferation and migration in lung cancer cell lines and the effect of the novel aPKC inhibitor DNDA (3,4-amino-2,7 napthalene disulfonic acid). METHODS: The normal and lung cancer cells were treated with various concentrations of DNDA. We used a WST assay to determine lung cell viability, then analyzed cell apoptosis through Annexin V/PI staining and flow cytometry. Immunoprecipitation determined the proteins' associations, and Western blot allowed testing of the expression of interest proteins. We also employed the UbiTest to identify the ubiquitination of the FAK. The scratch and transwell assays measured cell migration and invasion of lung cancer cells. RESULTS: Our data from cell viability and flow cytometry showed a significant reduction in cell proliferation and induction of apoptosis with DNDA treatment in lung cancer cells, as well as no toxic effect on normal BEAS-2B lung cells. Western blot results showed that the phosphorylation of PKC-iota and phosphorylation of FAK decreased in A549 lung cancer cells upon DNDA treatment. Immunoprecipitation (IP) data revealed an association of PKC-ι with FAK and FAK with Casitas B-lineage lymphoma proto-oncogene-b (Cbl-b). UbiTest results suggest that PKC-ι regulates FAK cleavage through its ubiquitination by Cbl-b, thereby inhibiting A549 lung cancer cells' migration. This was evident from scratch, invasion, and migration assays. CONCLUSION: Our study data suggest that DNDA inhibits cell proliferation and induces apoptosis in lung cancer cells. Moreover, DNDA inhibit A549 lung cancer cells' migration by PKC- ι/FAK ubiquitination via Cbl-b.
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Despite enormous scientific advancements in cancer treatment, there is a need for research to combat cancer, particularly bladder cancer. Drugs once proved to be effective in treating bladder cancer have shown reduced efficacy; hence, the cancer recurrence rate is increasing. To overcome this situation, several strategies have been considered, including the development of novel active drugs or modification of existing therapeutic regimens by combining two or more existing drugs. In recent years, atypical protein kinase Cs (PKCs), phospholipiddependent serine/threonine kinases, have been considered as a central regulator of various cancerassociated signaling pathways, and they control cell cycle progression, tumorigenesis and metastasis. Additionally, the biologically crucial mTOR signaling pathway is altered in numerous types of cancer, including bladder cancer. Furthermore, despite independent activation, atypical PKC signaling can be triggered by mTOR. The present study examined whether the concurrent inhibition of atypical PKCs and mTOR using a combination of novel atypical PKC inhibitors (ICAI, an inhibitor of PKCι; or ζStat, an inhibitor of PKCζ) and rapamycin blocks bladder cancer progression. In the present study, healthy bladder MCSVHUCT2 and bladder cancer TCCSUP cells were tested and subjected to a WST1 assay, western blot analysis, immunoprecipitation, a scratch wound healing assay, flow cytometry and immunofluorescence analyses. The results revealed that the combination therapy induced a reduction in human bladder cancer cell viability compared with control and individual atypical PKC inhibitor and rapamycin treatment. Additionally, the concurrent inhibition of atypical PKCs and mTOR retards the migration of bladder cancer cells. These findings indicated that the administration of atypical PKC inhibitors together with rapamycin could be a useful therapeutic option in treating bladder cancer.
Assuntos
Isoenzimas/antagonistas & inibidores , Proteína Quinase C/antagonistas & inibidores , Inibidores de Proteínas Quinases/farmacologia , Sirolimo/farmacologia , Neoplasias da Bexiga Urinária/enzimologia , Protocolos de Quimioterapia Combinada Antineoplásica , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Humanos , Estrutura Molecular , Nucleosídeos/análogos & derivados , Nucleosídeos/química , Inibidores de Proteínas Quinases/química , Transdução de Sinais/efeitos dos fármacos , Serina-Treonina Quinases TOR/antagonistas & inibidores , Neoplasias da Bexiga Urinária/tratamento farmacológicoRESUMO
Colorectal cancer (CRC) is the third most common malignancy and the fourth most common cause of cancer-related death worldwide. The treatment of metastatic CRC considered palliative for many years aiming for an improved life, with little hope of a cure, highlighting the need for developing novel targeted therapy for CRC. Human protein kinases constitute a complicated system with complex internal and external interactions, which stimulates various cellular processes such as cell growth, metabolism, survival, and apoptosis. This study investigated the effect of a combination of atypical Protein Kinase C (PKC) inhibitor (either ICA-I or ζ-Stat) and 5-FU (a thymidylate synthase inhibitor) on CRC cells viability concerning cellular DNA damage. In this study, we took multiple approaches such as colony formation assay, flow cytometry, DNA ladder assay, TUNEL assay, etc. to examine the CRC cell viability and apoptosis as a function of combination treatment. Our findings showed that the combination of atypical PKC inhibitor and 5-FU synergistically reduced the viability of CRC cells and induced apoptosis. Additionally, the DNA ladder and TUNEL assays indicated that there was a notable DNA damage and fragmentation because of lack of thymidylate synthase and due to the deactivation of atypical PKC dependent CDK7. These data suggest that the simultaneous knockdown of upstream atypical PKC protein and downstream DNA damage repairing mechanism would be a useful approach to combat CRC and to improve overall patients' survival rate.
Assuntos
Neoplasias Colorretais/enzimologia , Neoplasias Colorretais/patologia , Dano ao DNA , Fluoruracila/farmacologia , Proteína Quinase C/antagonistas & inibidores , Inibidores de Proteínas Quinases/farmacologia , Apoptose/efeitos dos fármacos , Linhagem Celular Tumoral , Sobrevivência Celular/efeitos dos fármacos , Fragmentação do DNA/efeitos dos fármacos , Reparo do DNA/efeitos dos fármacos , Sinergismo Farmacológico , Fluoruracila/química , Humanos , Imidazóis/farmacologia , Modelos Biológicos , Organofosfatos/farmacologia , Proteína Quinase C/metabolismo , Inibidores de Proteínas Quinases/química , Fator de Transcrição TFIIH/metabolismo , Ensaio Tumoral de Célula-TroncoRESUMO
Ovarian cancer is estimated to reach 22,530 diagnoses and cause 13,980 cancer deaths per year. The most common histology diagnosed of ovarian cancer is epithelial ovarian carcinomas (EOC). An aggressive epithelial subtype is clear cell ovarian carcinoma (CCOC) and is characterized as a non-serous ovarian cancer. Protein kinase C (PKC) is an enzymatic family of proteins that have been found to be a component in cancer progression, tissue invasion, and metastasis. The atypical PKC (aPKC) isoforms, PKC-ι and PKC-ζ, have been suggested to participate in the increased proliferation of ovarian cancers. Previous studies have indicated that novel aPKC inhibitors ICA-1S and ζ-Stat decreased the migratory behaviors of colorectal cancer cells and were selective for PKC-ι/λ and PKC-ζ, respectively. The aims of this investigation were to further determine the binding mechanisms of ζ-Stat, expand on the tissue range of these compounds, investigate the therapeutic potential of ζ-Stat in CCOC, and to illustrate the disruption of invasion via the PKC-ζ signaling cascade. The methods utilized were molecular docking and virtual target screening, Western blot analysis, end-point PCR, GST pull down, cell viability and invasion and migration assays. We discovered that the small molecule inhibitor, ζ-Stat, is a prospective drug candidate to investigate as a novel potential treatment for CCOC. We also found that the PKC-ζ/Ect2/Rac1 activation pathway was decreased by ζ-Stat, which in turn decreased invasive behavior of CCOC.
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It is estimated that breast cancer will be the second leading cause of cancer-associated mortality in women in 2018. Previous research has demonstrated that the atypical protein kinase C-ζ (PKC-ζ) is a component of numerous dysregulated pathways in breast cancer, including cellular proliferation, survival, and cell cycle upregulation. The present study investigated the PKC-ζ protein in breast tissue to evaluate its potential as a biomarker for breast cancer invasion, and demonstrated that an overexpression of PKC-ζ protein can be indicative of carcinogenesis. The present study analyzed the expression of PKC-ζ in individuals with no tumor complications and malignant female human breast tissue samples (lobular carcinoma in situ, invasive lobular carcinoma, ductal carcinoma in situ and invasive ductal carcinoma) with the use of western blot analysis, immunohistochemistry and statistical analysis (83 samples). The present study also evaluated the invasive behavior of MDA-MB-231 breast cancer cells following the knockdown of PKC-ζ with a Transwell invasion assay and an immunofluorescent probe for filamentous actin (F-actin) organization. The data demonstrated that PKC-ζ expression was identified to be higher in invading tissues when compared with non-invading tissues. The results also suggest that PKC-ζ is more abundant in ductal tissues when compared with lobular tissues. In addition, the protein studies also suggest that PKC-ζ is a component for invasive behavior through the Ras-related C3 botulinum toxin substrate 1 (Rac1) and Ras homolog gene family member A (RhoA) pathway, and PKC-ζ is required for the F-actin reorganization in invasive cells. Therefore, PKC-ζ should be considered to be a biomarker in the development of breast cancer as well as an indicator of invading tumor cells.
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Colorectal cancer (CRC) is the third most common cancer in the United States. The exact mechanism of CRC cells metastasis is poorly understood. Actin polymerization is thought to be an initial step in the cancer cell motility cycle which drives the formation of cell protrusions and defines the direction of migration. Cofilin, a significant actin-regulating molecule, regulates the migration of cancer cells by the formation of lamellipodia and filopodia, however, little is known about the upstream regulation of cofilin. In this study, the effect of atypical Protein Kinase C (atypical PKC) on Cofilin activity in CRC was studied. This study demonstrates that the atypical PKC inhibition impedes the metastasis of CRC cells by increasing phospho-Cofilin (S3) and changing actin organization.
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Fatores de Despolimerização de Actina/metabolismo , Actinas/metabolismo , Movimento Celular , Proliferação de Células , Neoplasias Colorretais/patologia , Proteína Quinase C/metabolismo , Fatores de Despolimerização de Actina/genética , Actinas/genética , Apoptose , Adesão Celular , Neoplasias Colorretais/metabolismo , Humanos , Metástase Neoplásica , Proteína Quinase C/genética , Células Tumorais CultivadasRESUMO
Prostate cancer (PC) is the most common type of cancer among men. Aggressive and metastatic PC results in life-threatening tumors, and represents one of the leading causes of mortality in men. Previous studies of atypical protein kinase C isoforms (aPKCs) have highlighted its role in the survival of cultured prostate cells via the nuclear factor (NF)-κB pathway. The present study showed that PKCι was overexpressed in PC samples collected from cancer patients but not in non-invasive prostate tissues, indicating PKCι as a possible prognostic biomarker for the progression of prostate carcinogenesis. Immunohistochemical staining further confirmed the association between PKCι and the prostate malignancy. The DU145 and PC3 PC cell lines, and the non-neoplastic RWPE1 prostatic epithelial cell line were cultured and treated with aPKC inhibitors 2acetyl1,3-cyclopentanedione (ACPD) and 5-amino1-(1R,2S,3S,4R)-2,3-dihydroxy-4-methylcyclopentyl)1H-imidazole-4-carboxamide (ICA1). Western blot data demonstrated that ICA1 was an effective and specific inhibitor of PKCι and that ACPD inhibited PKCι and PKCζ. Furthermore, the two inhibitors significantly decreased malignant cell proliferation and induced apoptosis. The inhibitors showed no significant cytotoxicity towards the RWPE1 cells, but exhibited cytostatic effects on the DU145 and PC3 cells prior to inducing apoptosis. The inhibition of aPKCs significantly reduced the translocation of NF-κB to the nucleus. Furthermore, this inhibition promoted apoptosis, reduced signaling for cell survival, and reduced the proliferation of PC cells, whereas the normal prostate epithelial cells were relatively unaffected. Overall, the results suggested that PKCι and PKCζ are essential for the progression of PC, and that ACPD and ICA1 can be effectively used as potential inhibitors in targeted therapy.
Assuntos
Biomarcadores Tumorais/antagonistas & inibidores , Isoenzimas/antagonistas & inibidores , Neoplasias da Próstata/patologia , Proteína Quinase C/antagonistas & inibidores , Inibidores de Proteínas Quinases/farmacologia , Transdução de Sinais/efeitos dos fármacos , Idoso , Apoptose/efeitos dos fármacos , Biomarcadores Tumorais/metabolismo , Linhagem Celular Tumoral , Núcleo Celular/efeitos dos fármacos , Núcleo Celular/metabolismo , Proliferação de Células/efeitos dos fármacos , Regulação para Baixo , Regulação Neoplásica da Expressão Gênica , Humanos , Isoenzimas/metabolismo , Masculino , Pessoa de Meia-Idade , NF-kappa B/metabolismo , Próstata/patologia , Neoplasias da Próstata/tratamento farmacológico , Proteína Quinase C/metabolismo , Inibidores de Proteínas Quinases/uso terapêuticoRESUMO
Melanoma is one of the fastest growing cancers in the United States and is accompanied with a poor prognosis owing to tumors being resistant to most therapies. Atypical protein kinase Cs (aPKC) are involved in malignancy in many cancers. We previously reported that aPKCs play a key role in melanoma's cell motility by regulating cell signaling pathways which induce epithelial-mesenchymal Transition (EMT). We tested three novel inhibitors; [4-(5-amino-4-carbamoylimidazol-1-yl)-2,3-dihydroxycyclopentyl] methyl dihydrogen phosphate (ICA-1T) along with its nucleoside analog 5-amino-1-((1R,2S,3S,4R)-2,3-dihydroxy-4-methylcyclopentyl)-1H-imidazole-4-carboxamide (ICA-1S) which are specific to protein kinase C-iota (PKC-ι) and 8-hydroxy-1,3,6-naphthalenetrisulfonic acid (ζ-Stat) which is specific to PKC-zeta (PKC-ζ) on cell proliferation, apoptosis, migration and invasion of two malignant melanoma cell lines compared to normal melanocytes. Molecular modeling was used to identify potential binding sites for the inhibitors and to predict selectivity. Kinase assay showed >50% inhibition for specified targets beyond 5 µM for all inhibitors. Both ICA-1 and ζ-Stat significantly reduced cell proliferation and induced apoptosis, while ICA-1 also significantly reduced migration and melanoma cell invasion. PKC-ι stimulated EMT via TGFß/Par6/RhoA pathway and activated Vimentin by phosphorylation at S39. Both ICA-1 and ζ-Stat downregulate TNF-α induced NF-κB translocation to the nucleus there by inducing apoptosis. Results suggest that PKC-ι is involved in melanoma malignancy than PKC-ζ. Inhibitors proved to be effective under in-vitro conditions and need to be tested in-vivo for the validity as effective therapeutics. Overall, results show that aPKCs are essential for melanoma progression and metastasis and that they could be used as effective therapeutic targets for malignant melanoma.
RESUMO
Atypical protein kinase Cs (aPKC) are involved in cell cycle progression, tumorigenesis, cell survival and migration in many cancers. We believe that aPKCs play an important role in cell motility of melanoma by regulating cell signaling pathways and inducing epithelial to mesenchymal transition (EMT). We have investigated the effects of two novel aPKC inhibitors; 2-acetyl-1,3-cyclopentanedione (ACPD) and 3,4-diaminonaphthalene-2,7-disulfonic acid (DNDA) on cell proliferation, apoptosis, migration and invasion of two malignant melanoma cell lines compared to normal melanocytes. Molecular docking data suggested that both inhibitors specifically bind to protein kinase C-zeta (PKC-ζ) and PKC-iota (PKC-ι) and kinase activity assays were carried out to confirm these observations. Both inhibitors decreased the levels of total and phosphorylated PKC-ζ and PKC-ι. Increased levels of E-cadherin, RhoA, PTEN and decreased levels of phosphorylated vimentin, total vimentin, CD44, ß-catenin and phosphorylated AKT in inhibitor treated cells. This suggests that inhibition of both PKC-ζ and PKC-ι using ACPD and DNDA downregulates EMT and induces apoptosis in melanoma cells. We also carried out PKC-ι and PKC-ζ directed siRNA treatments to prove the above observations. Immunoprecipitation data suggested an association between PKC-ι and vimentin and PKC-ι siRNA treatments confirmed that PKC-ι activates vimentin by phosphorylation. These results further suggested that PKC-ι is involved in signaling pathways which upregulate EMT and which can be effectively suppressed using ACPD and DNDA. Our results summarize that melanoma cells proliferate via aPKC/AKT/NF-κB mediated pathway while inducing the EMT via PKC-ι/Par6/RhoA pathway. Overall, results show that aPKCs are essential for melanoma progression and metastasis, suggesting that ACPD and DNDA can be effectively used as potential therapeutic drugs for melanoma by inhibiting aPKCs.
Assuntos
Isoenzimas/genética , Melanoma/tratamento farmacológico , Naftalenos/farmacologia , Proteína Quinase C/genética , Ácidos Sulfônicos/farmacologia , Apoptose/efeitos dos fármacos , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Dioxolanos/administração & dosagem , Dioxolanos/química , Transição Epitelial-Mesenquimal/efeitos dos fármacos , Regulação Neoplásica da Expressão Gênica/efeitos dos fármacos , Humanos , Isoenzimas/antagonistas & inibidores , Isoenzimas/química , Melanócitos/efeitos dos fármacos , Melanoma/genética , Melanoma/patologia , Simulação de Acoplamento Molecular , Naftalenos/uso terapêutico , Metástase Neoplásica , Proteína Quinase C/antagonistas & inibidores , Proteína Quinase C/química , Purinas/administração & dosagem , Purinas/química , RNA Interferente Pequeno/genética , Transdução de Sinais , Ácidos Sulfônicos/uso terapêuticoRESUMO
Increased flux through the hexosamine biosynthetic pathway (HBP) has been shown to affect the activity and translocation of certain protein kinase C (PKC) isoforms. It has been suggested that this effect is due to increases in the beta-O-linked N-acetylglucosamine (O-GlcNAc) modification. Herein, we demonstrate the effect of increasing the O-GlcNAc modification on the translocation of select PKC isozymes in a human astroglial cell line. Treating cells with either 8 mM d-glucosamine (GlcN), 5 mM streptozotocin (STZ), or 80 muM O-(2-acetamido-2-deoxy-d-glucopyranosylidene)amino-N-phenylcarbamate (PUGNAc) produced a significant increase in the O-GlcNAc modification on both cytosolic and membrane proteins; however, both the level and rate of O-GlcNAc increase varied with the compound. GlcN treatment resulted in a rapid, transient translocation of PKC-betaII that was maximal after 3 h (73+/-8%) and also produced a 48+/-15% decrease in membrane-associated PKC-epsilon after 9 h of treatment. Similar to GlcN treatment, STZ and PUGNAc treatment also resulted in decreased levels of PKC-epsilon in the membrane fraction. Significant decreases were seen as early as 5 h and, by 9 h of treatment, had decreased by 87+/-6% with STZ and 73+/-7% with PUGNAc. Unlike GlcN, both STZ and PUGNAc produced a decrease in PKC-alpha membrane levels by 9 h posttreatment (78+/-10% with STZ and 66+/-8% with PUGNAc) while neither compound produced any changes in PKC-betaII translocation. In addition, none of the three compounds affected membrane levels of PKC-iota. Altogether, these results demonstrate a novel link between increased levels of the O-GlcNAc modification and the regulation of specific PKC isoforms.
Assuntos
Acetilglucosamina/análogos & derivados , Acetilglucosamina/metabolismo , Proteína Quinase C/metabolismo , Acetilglucosamina/farmacologia , Linhagem Celular Transformada , Membrana Celular/enzimologia , Citosol/metabolismo , Eletroforese em Gel de Poliacrilamida , Glucosamina/farmacologia , Humanos , Immunoblotting , N-Acetilglucosaminiltransferases/metabolismo , Neuroglia , Oximas/farmacologia , Fenilcarbamatos/farmacologia , Proteína Quinase C-alfa , Proteína Quinase C-épsilon , Estreptozocina/farmacologiaRESUMO
Cyclin-dependent kinase activating kinase (CAK) is a trimeric complex composed of cdk7, cyclin H and MAT1. CAK/cdk7 functions as a master cell cycle regulator by phosphorylating cyclin-dependent kinases for cell cycle progression. We have previously reported that protein kinase C-iota (PKC-iota) associates with CAK/cdk7. In this investigation, immunofluorescence confocal microscopy was used to provide further evidence for the co-localization of PKC-iota with CAK/cdk7. PKC-iota was labeled with Alexa Fluor 488 (green fluorescent dye) and CAK/cdk7 was labeled with Alexa Fluor 555 (red fluorescent dye). The fusion of the red and green fluorescent colors produced a yellow color, which was used to quantify co-localization of PKC-iota and CAK/cdk7. Confocal microscopy revealed the co-localization of PKC-iota with CAK/cdk7 in both the cytoplasm and nucleus of U-373 MG cells.