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1.
Carcinogenesis ; 2024 Jul 25.
Article in English | MEDLINE | ID: mdl-39051454

ABSTRACT

RLIP acts as a transporter that responds to stress and provides protection, specifically against glutathione-electrophile conjugates and xenobiotic toxins. Its increased presence in malignant cells, especially in cancer, emphasizes its crucial anti-apoptotic function. This is achieved by selectively regulating the cellular levels of pro-apoptotic oxidized lipid byproducts. Suppressing the progression of tumors in human xenografts can be achieved by effectively inhibiting RLIP, a transporter in the mercapturic acid pathway, without involving chemotherapy. Utilizing ovarian cancer (OC) cell lines (MDAH2774, OVCAR4, and OVCAR8), we observed that agents targeting RLIP, such as RLIP antisense and RLIP antibodies, not only substantially impeded the viability of OC cells but also remarkably increased their sensitivity to carboplatin. To delve further into the cytotoxic synergy between RLIP antisense, RLIP antibodies, and carboplatin, we conducted investigations in both cell culture and xenografts of OC cells. The outcomes revealed that RLIP depletion via phosphorothioate antisense led to rapid and sustained remissions in established subcutaneous human ovary xenografts. Furthermore, RLIP inhibition by RLIP antibodies exhibited comparable efficacy to antisense and enhanced the effectiveness of carboplatin in MDAH2774 OC xenografts. These investigations underscore RLIP as a central carrier crucial for supporting the survival of cancer cells, positioning it as a suitable focus for cancer treatment.

2.
Carcinogenesis ; 42(1): 48-57, 2021 02 11.
Article in English | MEDLINE | ID: mdl-32426802

ABSTRACT

Breast cancer (BC) remains one of the major causes of cancer deaths in women. Over half of all BCs carry genetic defects in the gene encoding p53, a powerful tumor suppressor. P53 is known as the 'guardian of the genome' because it is essential for regulating cell division and preventing tumor formation. Ral-interacting protein (RLIP) is a modular protein capable of participating in many cellular functions. Blocking this stress-responsive protein, which is overexpressed during malignancy, enables BC cells to overcome the deleterious effects of p53 loss more effectively. In the clustered regularly interspaced short palindromic repeats/CRISPR-associated protein (CRISPR/Cas9) system, a single-guide RNA (sgRNA) recognizes a specific DNA sequence and directs the endonuclease Cas9 to make a double-strand break, which enables editing of targeted genes. Here, we harnessed CRISPR/Cas9 technology to target the RLIP gene in BC cells. We screened sgRNAs using a reporter system and lentivirally delivered them, along with Cas9, to BC cells for validation. We then assessed the survival, proliferation, and tumorigenicity of BC cells in vitro and the growth of tumors in vivo after CRISPR-mediated knockdown of RLIP. Doxycycline-inducible expression of Cas9 in BC cells transduced with lentiviral vectors encoding the sgRNAs disrupted the RLIP gene, leading to inhibition of BC cell proliferation both in vitro and in vivo, with resected tumors showing reduced levels of the survival and proliferation markers Ki67, RLIP, pAkt, and survivin, the cell cycle protein CDK4, and the mesenchymal marker vimentin, as well as elevated levels of the differentiation protein E-cadherin and pro-apoptotic protein Bim. Inducible Cas9/sgRNA-transduced BC cells without doxycycline treatment did not exhibit altered cell survival or proliferation in vitro or in vivo. Our study provides proof-of-concept that the CRISPR/Cas9 system can be utilized to target RLIP in vitro and in vivo.


Subject(s)
ATP-Binding Cassette Transporters/genetics , Breast Neoplasms/therapy , CRISPR-Cas Systems/genetics , GTPase-Activating Proteins/genetics , Genetic Therapy/methods , ATP-Binding Cassette Transporters/metabolism , Apoptosis/genetics , Breast Neoplasms/genetics , Carcinogenesis/genetics , Cell Line, Tumor , Cell Proliferation/genetics , Cell Survival/genetics , Female , GTPase-Activating Proteins/metabolism , Gene Editing/methods , Gene Knockdown Techniques , Humans , Proof of Concept Study , RNA, Guide, Kinetoplastida/genetics , Xenograft Model Antitumor Assays
3.
Carcinogenesis ; 42(5): 742-752, 2021 05 28.
Article in English | MEDLINE | ID: mdl-33623991

ABSTRACT

The incidence of malignant melanoma, a neoplasm of melanocytic cells, is increasing rapidly. The lymph nodes are often the first site of metastasis and can herald systemic dissemination, which is almost uniformly fatal. RLIP, a multi-specific ATP-dependent transporter that is over-expressed in several types of cancers, plays a central role in cancer cell resistance to radiation and chemotherapy. RLIP appears to be necessary for cancer cell survival because both in vitro cell culture and in vivo animal tumor studies show that the depletion or inhibition of RLIP causes selective toxicity to malignant cells. RLIP depletion/inhibition triggers apoptosis in cancer cells by inducing the accumulation of endogenously formed glutathione-conjugates. In our in vivo studies, we administered RLIP antibodies or antisense oligonucleotides to mice bearing subcutaneous xenografts of SKMEL2 and SKMEL5 melanoma cells and demonstrated that both treatments caused significant xenograft regression with no apparent toxic effects. Anti-RLIP antibodies and antisense, which respectively inhibit RLIP-mediated transport and deplete RLIP expression, showed similar tumor regressing activities, indicating that the inhibition of RLIP transport activity at the cell surface is sufficient to achieve anti-tumor activity. Furthermore, RLIP antisense treatment reduced levels of RLIP, pSTAT3, pJAK2, pSrc, Mcl-1 and Bcl2, as well as CDK4 and cyclin B1, and increased levels of Bax and phospho 5' AMP-activated protein kinase (pAMPK). These studies indicate that RLIP serves as a key effector in the survival of melanoma cells and is a valid target for cancer therapy. Overall, compounds that inhibit, deplete or downregulate RLIP will function as wide-spectrum agents to treat melanoma, independent of common signaling pathway mutations.


Subject(s)
ATP-Binding Cassette Transporters/genetics , GTPase-Activating Proteins/genetics , Janus Kinase 2/genetics , Melanoma/genetics , STAT3 Transcription Factor/genetics , ATP-Binding Cassette Transporters/antagonists & inhibitors , ATP-Binding Cassette Transporters/immunology , Animals , Antibodies, Anti-Idiotypic/pharmacology , Apoptosis/genetics , Cell Line, Tumor , Cell Survival/genetics , GTPase-Activating Proteins/antagonists & inhibitors , GTPase-Activating Proteins/immunology , Humans , Melanoma/pathology , Mice , Neoplasm Proteins/genetics , Signal Transduction/genetics , Xenograft Model Antitumor Assays
4.
Mol Carcinog ; 60(3): 213-223, 2021 03.
Article in English | MEDLINE | ID: mdl-33544936

ABSTRACT

The overexpression and amplification of the protooncogene neu (ERBB2) play an important role in the development of aggressive breast cancer (BC) in humans. Ral-interacting protein (RLIP), a modular stress-response protein with pleiotropic functions, is overexpressed in several types of cancer, including BC. Here, we show that blocking RLIP attenuates the deleterious effects caused by the loss of the tumor suppressor p53 and inhibits the growth of human BC both in vitro and in vivo in MMTV-neu mice. In addition, we show that treatment with the diet-derived, RLIP-targeting chemotherapeutic 2'-hydroxyflavanone (2HF), alone or in combination with RLIP-specific antisense RNA or antibodies, significantly reduced the cumulative incidence and/or burden of mammary hyperplasia and carcinoma in MMTV-neu mice. 2HF treatment correlated with reduced tumor cell proliferation and increased apoptosis, and the average number of Ki67-positive (proliferating) cells was significantly lower in the tumors of 2HF-treated mice than in the tumors of control mice. Furthermore, targeting RLIP also resulted in the overexpression of E-cadherin and the infiltration of CD3+ T cells into mammary tumors. Taken together, these results underscore the translational potential of RLIP-targeting agents and provide a strong rationale to validate them in the clinic.


Subject(s)
ATP-Binding Cassette Transporters/metabolism , Anticarcinogenic Agents/pharmacology , Breast Neoplasms/metabolism , GTPase-Activating Proteins/metabolism , Mammary Neoplasms, Experimental/prevention & control , Animals , Breast Neoplasms/pathology , Cell Line, Tumor , Female , Flavanones/pharmacology , GTPase-Activating Proteins/genetics , Humans , Lymphocytes, Tumor-Infiltrating/drug effects , Mammary Glands, Animal/drug effects , Mammary Neoplasms, Experimental/genetics , Mammary Neoplasms, Experimental/pathology , Mice, Transgenic , Molecular Targeted Therapy , Proto-Oncogene Proteins c-akt/metabolism , Proto-Oncogene Proteins c-bcl-2/metabolism , Receptor, ErbB-2/metabolism
5.
Proc Natl Acad Sci U S A ; 115(15): 3918-3923, 2018 04 10.
Article in English | MEDLINE | ID: mdl-29572430

ABSTRACT

TP53 (p53) is a tumor suppressor whose functions are lost or altered in most malignancies. p53 homozygous knockout (p53-/-) mice uniformly die of spontaneous malignancy, typically T-cell lymphoma. RALBP1 (RLIP76, Rlip) is a stress-protective, mercapturic acid pathway transporter protein that also functions as a Ral effector involved in clathrin-dependent endocytosis. In stark contrast to p53-/- mice, Rlip-/- mice are highly resistant to carcinogenesis. We report here that partial Rlip deficiency induced by weekly administration of an Rlip-specific phosphorothioate antisense oligonucleotide, R508, strongly inhibited spontaneous as well as benzo(a)pyrene-induced carcinogenesis in p53-/- mice. This treatment effectively prevented large-scale methylomic and transcriptomic abnormalities suggestive of inflammation found in cancer-bearing p53-/- mice. The remarkable efficiency with which Rlip deficiency suppresses spontaneous malignancy in p53-/- mice has not been observed with any previously reported pharmacologic or genetic intervention. These findings are supported by cross-breeding experiments demonstrating that hemizygous Rlip deficiency also reduces the spontaneous malignancy phenotype of p53+/- mice. Rlip is found on the cell surface, and antibodies directed against Rlip were found to inhibit growth and promote apoptosis of cell lines as effectively as Rlip siRNA. The work presented here investigates several features, including oxidative DNA damage of the Rlip-p53 association in malignant transformation, and offers a paradigm for the mechanisms of tumor suppression by p53 and the prospects of suppressing spontaneous malignancy in hereditary cancer syndromes such as Li-Fraumeni.


Subject(s)
GTPase-Activating Proteins/deficiency , Neoplasms/genetics , Neoplasms/prevention & control , Tumor Suppressor Protein p53/genetics , Animals , Apoptosis , Female , GTPase-Activating Proteins/genetics , Humans , Male , Mice , Mice, Inbred C57BL , Mice, Knockout , Neoplasms/metabolism , Neoplasms/physiopathology , Tumor Suppressor Protein p53/metabolism , Tumor Suppressor Proteins/deficiency , Tumor Suppressor Proteins/metabolism
6.
Biochim Biophys Acta Rev Cancer ; 1868(1): 167-175, 2017 Aug.
Article in English | MEDLINE | ID: mdl-28359741

ABSTRACT

Prostate cancer (CaP) is often androgen-sensitive malignancy and regresses upon inhibition of androgen signaling. However, CaP, nearly always develops androgen resistance and progresses to aggressive and lethal androgen-independent CaP, which lacks satisfactory therapy. For metastatic CaP, patients are often treated with Taxotere (docetaxel), a cytoskeleton-targeted chemotherapy drug, that provides transient palliative benefit but to which patients rapidly develop drug-resistance. Combination chemotherapy may be used instead, but is more toxic and adds little clinically relevant benefit over docetaxel. Therefore, novel strategies to enhance docetaxel efficacy are needed to effectively treat patients with metastatic CaP. The mercapturic acid pathway, which metabolizes genotoxic and pro-apoptotic toxins, is over-expressed in CaP and plays an important role in carcinogenesis, metastasis and therapy-resistance of CaP. Vicenin-2, a flavonoid derived from Tulsi (holy basil) as an active compound, inhibits the growth of CaP and increases the anti-tumor activity of docetaxel in-vitro and in-vivo. Taken together, the combination of vicenin-2 and docetaxel could be highly effective in the treatment of advanced and metastatic CaP due to their multi-targeting anti-tumor potential.


Subject(s)
Acetylcysteine/metabolism , Antineoplastic Agents/pharmacology , Antineoplastic Agents/therapeutic use , Apigenin/metabolism , Glucosides/metabolism , Prostatic Neoplasms/drug therapy , Prostatic Neoplasms/metabolism , Signal Transduction/drug effects , Animals , Docetaxel , Drug Resistance, Neoplasm/drug effects , Humans , Male , Taxoids/pharmacology , Taxoids/therapeutic use
7.
Mol Carcinog ; 58(8): 1438-1449, 2019 08.
Article in English | MEDLINE | ID: mdl-31006917

ABSTRACT

Substantial evidence suggests that 7,12-dimethylbenzanthracene (DMBA)-induced mammary carcinogenesis in mice mimics human breast cancer (BC) in many respects. Therefore, it has been used extensively to evaluate preventive and therapeutic agents for human BC. Mammary carcinogenesis induced by DMBA administration in female SENsitive to CARcinogen (SENCAR) mice was characterized by histopathological analysis of the mammary glands and alterations to the phosphatidylinositol 3-kinase/protein kinase B/cyclin-dependent kinase 1 (PI3K/Akt/CDK1) pathway. We recently reported that 2'-hydroxyflavanone (2HF) is a promising diet-derived chemotherapeutic agent that suppresses BC growth in vitro and in vivo by targeting a 76 kDa ral-interacting protein (RLIP). The objective of the current study was to investigate the synergistic anticarcinogenic effects of RLIP inhibition/depletion and 2HF in an in vivo model of DMBA-induced mammary carcinogenesis in SENCAR mice. Mice were given 2HF (50 mg/kg, bw, orally on alternate days), RLIP antibody (Rab; 5 mg/kg, bw, ip weekly), RLIP antisense (RAS; 5 mg/kg, b.w., ip weekly), or a combination of 2HF + Rab + RAS. Animals were monitored daily, and 7 days after the first appearance of moribund behavior, tissues were harvested for morphological and immunohistological analysis. Western blot analyses were performed to determine the expression of anti- and proapoptotic proteins in the mammary glands. Our results reveal that 2HF, RAS, and Rab significantly prevented the carcinogenic effects of DMBA administration in the mammary glands and other organs. Further, mice treated with a combination of 2HF + RAS + Rab exhibited no carcinogenic effect of DMBA as compared to either or the single agent-treated mice. This study demonstrates for the first time the anticarcinogenic effects of 2HF and RLIP inhibition/depletion in vivo in a novel DMBA-induced model of BC in SENCAR mice and provides the rationale for further clinical investigation.


Subject(s)
9,10-Dimethyl-1,2-benzanthracene/toxicity , Anticarcinogenic Agents/pharmacology , Cell Transformation, Neoplastic/pathology , Flavanones/pharmacology , GTPase-Activating Proteins/antagonists & inhibitors , Mammary Neoplasms, Experimental/prevention & control , Animals , CDC2 Protein Kinase/metabolism , Disease Models, Animal , Female , GTPase-Activating Proteins/genetics , Mammary Glands, Animal/pathology , Mammary Neoplasms, Experimental/pathology , Mice , Mice, Inbred SENCAR , Phosphatidylinositol 3-Kinases/metabolism , Proto-Oncogene Proteins c-akt/metabolism
8.
Int J Cancer ; 142(4): 658-670, 2018 02 15.
Article in English | MEDLINE | ID: mdl-28975625

ABSTRACT

Breast cancer (BC) prevention and therapy in the context of life-style risk factors and biological drivers is a major focus of developmental therapeutics in oncology. Obesity, alcohol, chronic estrogen signaling and smoking have distinct BC precipitating and facilitating effects that may act alone or in combination. A spectrum of signaling events including enhanced oxidative stress and changes in estrogen-receptor (ER)-dependent and -independent signaling drive the progression of BC. Breast tumors modulate ERα/ERß ratio, upregulate proliferative pathways driven by ERα and HER2 with a parallel loss and/or downregulation of tumor suppressors such as TP53 and PTEN which together impact the efficacy of therapeutic strategies and frequently lead to emergence of drug resistance. Natural phytochemicals modulate oxidative stress, leptin, integrin, HER2, MAPK, ERK, Wnt/ß-catenin and NFκB signaling along with regulating ERα and ERß, thereby presenting unique opportunities for both primary and combinatorial interventions in BC. In this regard, this article focuses on critical analyses of the evidence from multiple studies on the efficacy of natural phytochemicals in BC. In addition, areas in which the combinations of such effective natural phytochemicals with approved and/or developing anticancer agents can be translationally beneficial are discussed to derive evidence-based inference for addressing challenges in BC control and therapy.


Subject(s)
Biomarkers, Tumor/antagonists & inhibitors , Breast Neoplasms/prevention & control , Molecular Targeted Therapy , Phytochemicals/therapeutic use , Translational Research, Biomedical , Breast Neoplasms/metabolism , Drug Therapy, Combination , Female , Humans
9.
Mol Carcinog ; 57(12): 1751-1762, 2018 12.
Article in English | MEDLINE | ID: mdl-30136444

ABSTRACT

Consumption of citrus-fruits is associated with reduced incidence of breast cancer (BC), the most common cancer diagnosed in women across the globe. In this study, we investigated the anticancer potential of 2-Hydroxyflavanone (2HF) in BC. 2HF, a citrus-bioflavonoid, has demonstrated anticancer properties in various cancers, but its anticancer role in BC has not been well studied. We investigated the in vitro and in vivo growth inhibitory effects of 2HF in an array of BC lines and in xenograft mouse models of ER-positive and HER2-positive BC cells. Compared to control, 2HF treatment reduced cell viability and suppressed migratory and invasive potential of BC cells, while, no growth inhibitory effects were observed in non-tumorigenic breast epithelial cells. Further, 2HF inhibited the expression of RLIP76, a stress-defensive and anti-apoptotic protein, which is over-expressed in BC cells and simultaneously reduced proliferation of BC cells. Nude mice bearing MCF7 or SKBR3 BC cells xenografts treated with either 2HF or targeting RLIP76 by RLIP76-antisense or RLIP76-antibody treatment had significantly lower tumor-weight as compared to corresponding controls. In addition, Western-blotting and immunohistochemical analysis of tumor tissue from control and treatment group mice showed that 2HF decreased protein expression levels of RLIP76, and the decrease was similar to those seen following RLIP76-antisense treatment. Furthermore, 2HF decreased expression of Ki67, CD31, vimentin, inhibited phosphorylation of Akt and expression of survivin and Bcl2, and increased levels of Bax, E-cadherin, and cleaved-PARP. Therefore, our results indicate that 2HF may suppress BC growth in vitro and in vivo by targeting RLIP76, and may serve as a potential adjuvant treatment in BC patients.


Subject(s)
ATP-Binding Cassette Transporters/genetics , ATP-Binding Cassette Transporters/metabolism , Antineoplastic Agents, Phytogenic/administration & dosage , Breast Neoplasms/drug therapy , Flavanones/administration & dosage , GTPase-Activating Proteins/genetics , GTPase-Activating Proteins/metabolism , Animals , Antineoplastic Agents, Phytogenic/pharmacology , Breast Neoplasms/genetics , Breast Neoplasms/metabolism , Cell Line, Tumor , Cell Movement/drug effects , Cell Survival/drug effects , Female , Flavanones/pharmacology , Gene Expression Regulation, Neoplastic/drug effects , Humans , MCF-7 Cells , Mice , Mice, Nude , Signal Transduction/drug effects , Up-Regulation/drug effects , Xenograft Model Antitumor Assays
10.
Pharm Res ; 34(8): 1673-1682, 2017 Aug.
Article in English | MEDLINE | ID: mdl-28386633

ABSTRACT

Refractory and relapsed neuroblastoma (NB) present with significant challenges in clinical management. Though primary NBs largely with wild-type p53 respond well to interventions, dysfunctional signaling in the p53 pathways in a MYCN oncogene driven background is found in a number of children with NB. The p53-mutant NB is largely unresponsive to available therapies and p53-independent targeted therapeutics represents a vital need in pediatric oncology. We analyzed the findings on mercapturic acid pathway (MAP) transporter RLIP76, which has broad and critical effects on multiple pathways as essential for carcinogenesis, oxidative stress and drug-resistance, is over-expressed in NB. RLIP76 inhibition by antibodies or depletion by antisense causes apoptosis and sensitization to chemo-radiotherapy in many cancers. In addition, recent studies indicate that the interactions between p53, MYCN, and WNT regulate apoptosis resistance and protein ubiquitination. RLIP76 and p53 interact with each other and colocalize in NB cells. Targeted depletion/inhibition of RLIP76 causes apoptosis and tumor regression in NB irrespective of p53 status. In the present review, we discuss the mechanisms and the role of RLIP76 in oxidative stress, drug-resistance and clathrin-dependent endocytosis (CDE), and analyze the molecular basis for the role of RLIP76 targeted approaches in the context principal drivers of NB pathogenesis, progression and drug-resistance. The evidence from RLIP76 studies in other cancers, when taken in the context of our recent RLIP76 focused mechanistic studies in NB, provides strong basis for further characterization and development of RLIP76 targeted therapies for NB.


Subject(s)
ATP-Binding Cassette Transporters/antagonists & inhibitors , Antineoplastic Agents/therapeutic use , Brain Neoplasms/drug therapy , GTPase-Activating Proteins/antagonists & inhibitors , Neuroblastoma/drug therapy , Animals , Antibodies/therapeutic use , Apoptosis , Biological Transport , Brain Neoplasms/pathology , Cell Line, Tumor , Child , Clathrin/metabolism , Drug Resistance, Neoplasm , Endocytosis , Glutathione , Humans , Molecular Targeted Therapy , Mutation , Neoplasm Recurrence, Local , Neuroblastoma/pathology , Oxidative Stress , Signal Transduction , Tumor Suppressor Protein p53/genetics , Tumor Suppressor Protein p53/metabolism
11.
J Biol Chem ; 290(51): 30321-41, 2015 Dec 18.
Article in English | MEDLINE | ID: mdl-26534958

ABSTRACT

Mitochondrial oxidative phosphorylation produces most of the energy in aerobic cells by coupling respiration to the production of ATP. Mitochondrial uncouplers, which reduce the proton gradient across the mitochondrial inner membrane, create a futile cycle of nutrient oxidation without generating ATP. Regulation of mitochondrial dysfunction and associated cellular bioenergetics has been recently identified as a promising target for anticancer therapy. Here, we show that SR4 is a novel mitochondrial uncoupler that causes dose-dependent increase in mitochondrial respiration and dissipation of mitochondrial membrane potential in HepG2 hepatocarcinoma cells. These effects were reversed by the recoupling agent 6-ketocholestanol but not cyclosporin A and were nonexistent in mitochondrial DNA-depleted HepG2 cells. In isolated mouse liver mitochondria, SR4 similarly increased oxygen consumption independent of adenine nucleotide translocase and uncoupling proteins, decreased mitochondrial membrane potential, and promoted swelling of valinomycin-treated mitochondria in potassium acetate medium. Mitochondrial uncoupling in HepG2 cells by SR4 results in the reduction of cellular ATP production, increased ROS production, activation of the energy-sensing enzyme AMPK, and inhibition of acetyl-CoA carboxylase and mammalian target of rapamycin signaling pathways, leading to cell cycle arrest and apoptosis. Global analysis of SR4-associated differential gene expression confirms these observations, including significant induction of apoptotic genes and down-regulation of cell cycle, mitochondrial, and oxidative phosphorylation pathway transcripts at 24 h post-treatment. Collectively, our studies demonstrate that the previously reported indirect activation of AMPK and in vitro anticancer properties of SR4 as well as its beneficial effects in both animal xenograft and obese mice models could be a direct consequence of its mitochondrial uncoupling activity.


Subject(s)
AMP-Activated Protein Kinases/metabolism , Carcinoma, Hepatocellular/metabolism , Liver Neoplasms/metabolism , Mitochondria, Liver/metabolism , Neoplasm Proteins/metabolism , Oxidative Phosphorylation/drug effects , TOR Serine-Threonine Kinases/metabolism , Uncoupling Agents/pharmacology , AMP-Activated Protein Kinases/genetics , Animals , Carcinoma, Hepatocellular/genetics , Carcinoma, Hepatocellular/pathology , Cell Proliferation/drug effects , Gene Expression Regulation, Neoplastic/drug effects , Hep G2 Cells , Humans , Liver Neoplasms/genetics , Liver Neoplasms/pathology , Mice , Mitochondria, Liver/genetics , Mitochondria, Liver/pathology , Neoplasm Proteins/genetics , Oxygen Consumption/drug effects , Oxygen Consumption/genetics , TOR Serine-Threonine Kinases/genetics
12.
Biochem Biophys Res Commun ; 467(4): 785-91, 2015 Nov 27.
Article in English | MEDLINE | ID: mdl-26498519

ABSTRACT

R-Ras small GTPase enhances cell spreading and motility via RalBP1/RLIP76, an R-Ras effector that links GTP-R-Ras to activation of Arf6 and Rac1 GTPases. Here, we report that RLIP76 performs these functions by binding cytohesin-2/ARNO, an Arf GTPase guanine exchange factor, and connecting it to R-Ras at recycling endosomes. RLIP76 formed a complex with R-Ras and ARNO by binding ARNO via its N-terminus (residues 1-180) and R-Ras via residues 180-192. This complex was present in Rab11-positive recycling endosomes and the presence of ARNO in recycling endosomes required RLIP76, and was not supported by RLIP76(Δ1-180) or RLIP76(Δ180-192). Spreading and migration required RLIP76(1-180), and RLIP76(Δ1-180) blocked ARNO recruitment to recycling endosomes, and spreading. Arf6 activation with an ArfGAP inhibitor overcame the spreading defects in RLIP76-depleted cells or cells expressing RLIP76(Δ1-180). Similarly, RLIP76(Δ1-180) or RLIP76(Δ180-192) suppressed Arf6 activation. Together these results demonstrate that RLIP76 acts as a scaffold at recycling endosomes by binding activated R-Ras, recruiting ARNO to activate Arf6, thereby contributing to cell spreading and migration.


Subject(s)
ADP-Ribosylation Factors/metabolism , GTPase-Activating Proteins/metabolism , ras Proteins/metabolism , ADP-Ribosylation Factor 6 , Animals , Base Sequence , Cell Movement/physiology , Endosomes/metabolism , Female , Fibroblasts/metabolism , GTPase-Activating Proteins/genetics , Mice, Inbred C57BL , Mice, Knockout , Molecular Sequence Data , Multiprotein Complexes/metabolism , Signal Transduction , ras Proteins/genetics
13.
Toxicol Appl Pharmacol ; 289(3): 361-70, 2015 Dec 15.
Article in English | MEDLINE | ID: mdl-26476300

ABSTRACT

4-Hydroxy-2-trans-nonenal (4HNE), one of the major end products of lipid peroxidation (LPO), has been shown to induce apoptosis in a variety of cell lines. It appears to modulate signaling processes in more than one way because it has been suggested to have a role in signaling for differentiation and proliferation. It has been known that glutathione S-transferases (GSTs) can reduce lipid hydroperoxides through their Se-independent glutathione-peroxidase activity and that these enzymes can also detoxify LPO end-products such as 4HNE. Available evidence from earlier studies together with results of recent studies in our laboratories strongly suggests that LPO products, particularly hydroperoxides and 4HNE, are involved in the mechanisms of stress-mediated signaling and that it can be modulated by the alpha-class GSTs through the regulation of the intracellular concentrations of 4HNE. We demonstrate that 4HNE induced apoptosis in various cell lines is accompanied with c-Jun-N-terminal kinase (JNK) and caspase-3 activation. Cells exposed to mild, transient heat or oxidative stress acquire the capacity to exclude intracellular 4HNE at a faster rate by inducing GSTA4-4 which conjugates 4HNE to glutathione (GSH), and RLIP76 which mediates the ATP-dependent transport of the GSH-conjugate of 4HNE (GS-HNE). The balance between formation and exclusion promotes different cellular processes - higher concentrations of 4HNE promote apoptosis; whereas, lower concentrations promote proliferation. In this article, we provide a brief summary of the cellular effects of 4HNE, followed by a review of its GST-catalyzed detoxification, with an emphasis on the structural attributes that play an important role in the interactions with alpha-class GSTA4-4. Taken together, 4HNE is a key signaling molecule and that GSTs being determinants of its intracellular concentrations, can regulate stress-mediated signaling, are reviewed in this article.


Subject(s)
Aldehydes/metabolism , Antioxidants/metabolism , Glutathione Transferase/metabolism , Isoenzymes/metabolism , Oxidative Stress/physiology , Signal Transduction/physiology , Animals , Apoptosis/physiology , Cell Proliferation/physiology , Humans , Lipid Peroxidation/physiology
14.
Pharm Res ; 32(10): 3123-36, 2015 Oct.
Article in English | MEDLINE | ID: mdl-26021465

ABSTRACT

Despite recent improvements in chemotherapeutic approaches to treating kidney cancer, this malignancy remains deadly if not found and removed at an early stage of the disease. Kidney cancer is highly drug-resistant, which may at least partially result from high expression of transporter proteins in the cell membranes of kidney cells. Although these transporter proteins can contribute to drug-resistance, targeting proteins from the ATP-binding cassette transporter family has not been effective in reversing drug-resistance in kidney cancer. Recent studies have identified RLIP76 as a key stress-defense protein that protects normal cells from damage caused by stress conditions, including heat, ultra-violet light, X-irradiation, and oxidant/electrophilic toxic chemicals, and is crucial for protecting cancer cells from apoptosis. RLIP76 is the predominant glutathione-electrophile-conjugate (GS-E) transporter in cells, and inhibiting it with antibodies or through siRNA or antisense causes apoptosis in many cancer cell types. To date, blocking of RLIP76, either alone or in combination with chemotherapeutic drugs, as a therapeutic strategy for kidney cancer has not yet been evaluated in human clinical trials, although there is considerable potential for RLIP76 to be developed as a therapeutic agent for kidney cancer. In the present review, we discuss the mechanisms underlying apoptosis caused by RLIP76 depletion, the role of RLIP76 in clathrin-dependent endocytosis deficiency, and the feasibility of RLIP76-targeted therapy for kidney cancer.


Subject(s)
ATP-Binding Cassette Transporters/metabolism , Antineoplastic Agents/pharmacology , Antineoplastic Agents/therapeutic use , Kidney Neoplasms/drug therapy , Animals , Apoptosis/drug effects , Drug Resistance, Neoplasm/drug effects , Endocytosis/physiology , Glutathione/metabolism , Humans , Kidney Neoplasms/metabolism
15.
J Biol Chem ; 288(32): 23394-406, 2013 Aug 09.
Article in English | MEDLINE | ID: mdl-23821548

ABSTRACT

Feeding a Western high-fat diet (HFD) to C57BL/6 mice induces obesity, associated with a chronic inflammatory state, lipid transport, and metabolic derangements, and organ system effects that particularly prominent in the kidneys. Here, we report that RLIP76 homozygous knock-out (RLIP76(-/-)) mice are highly resistant to obesity as well as these other features of metabolic syndrome caused by HFD. The normal increase in pro-inflammatory and fibrotic markers associated with HFD induced obesity in wild-type C57B mice was broadly and nearly completely abrogated in RLIP76(-/-) mice. This is a particularly striking finding because chemical markers of oxidative stress including lipid hydroperoxides and alkenals were significantly higher in RLIP76(-/-) mice. Whereas HFD caused marked suppression of AMPK in wild-type C57B mice, RLIP76(-/-) mice had baseline activation of AMP-activated protein kinase, which was not further affected by HFD. The baseline renal function was reduced in RLIP76(-/-) mice as compared with wild-type, but was unaffected by HFD, in marked contrast to severe renal impairment and glomerulopathy in the wild-type mice given HFD. Our findings confirm a fundamental role of RLIP76 in regulating the function of obesity-promoting pro-inflammatory cytokines, and provide a novel mechanism for targeted therapy of obesity and metabolic syndrome.


Subject(s)
Cytokines/metabolism , Dietary Fats/adverse effects , GTPase-Activating Proteins/metabolism , Metabolic Syndrome/metabolism , Obesity/metabolism , Oxidative Stress/drug effects , AMP-Activated Protein Kinases/genetics , AMP-Activated Protein Kinases/metabolism , Animals , Biomarkers/metabolism , Cytokines/genetics , Dietary Fats/pharmacology , Enzyme Activation/drug effects , Enzyme Activation/genetics , GTPase-Activating Proteins/genetics , Gene Knockdown Techniques , Inflammation/chemically induced , Inflammation/genetics , Inflammation/metabolism , Metabolic Syndrome/chemically induced , Metabolic Syndrome/genetics , Mice , Mice, Knockout , Obesity/chemically induced , Obesity/genetics , Oxidative Stress/genetics
16.
Apoptosis ; 19(5): 776-88, 2014 May.
Article in English | MEDLINE | ID: mdl-24615331

ABSTRACT

Methylglyoxal (MGO) is a highly reactive dicarbonyl compound known to induce cellular injury and cytoxicity, including apoptosis in vascular cells. Vascular endothelial cell apoptosis has been implicated in the pathophysiology and progression of atherosclerosis. We investigated whether the advanced glycation end-product inhibitor LR-90 could prevent MGO-induced apoptosis in human umbilical vascular endothelial cells (HUVECs). HUVECs were pre-treated with LR-90 and then stimulated with MGO. Cell morphology, cytotoxicity and apoptosis were evaluated by light microscopy, MTT assay, and Annexin V-FITC and propidium iodide double staining, respectively. Levels of Bax, Bcl-2, cytochrome c, mitogen-activated protein kinases (MAPKs) and caspase activities were assessed by Western blotting. Reactive oxygen species (ROS) generation and mitochondrial membrane potential (MMP) were measured with fluorescent probes. LR-90 dose-dependently prevented MGO-associated HUVEC cytotoxicity and apoptotic biochemical changes such as loss of MMP, increased Bax/Bcl-2 protein ratio, mitochondrial cytochrome c release and activation of caspase-3 and 9. Additionally, LR-90 blocked intracellular ROS formation and MAPK (p44/p42, p38, JNK) activation, though the latter seem to be not directly involved in MGO-induced HUVEC apoptosis. LR-90 prevents MGO-induced HUVEC apoptosis by inhibiting ROS and associated mitochondrial-dependent apoptotic signaling cascades, suggesting that LR-90 possess cytoprotective ability which could be beneficial in prevention of diabetic related-atherosclerosis.


Subject(s)
Antioxidants/pharmacology , Apoptosis/drug effects , Butyrates/pharmacology , Human Umbilical Vein Endothelial Cells/drug effects , Oxidative Stress/drug effects , Pyruvaldehyde/metabolism , Caspases/metabolism , Cytochromes c/metabolism , Enzyme Activation , Human Umbilical Vein Endothelial Cells/cytology , Human Umbilical Vein Endothelial Cells/metabolism , Humans , Membrane Potential, Mitochondrial/drug effects , Mitochondria/drug effects , Mitochondria/metabolism , Mitochondrial Membranes/drug effects , Mitochondrial Membranes/metabolism , Mitogen-Activated Protein Kinases/metabolism , Pyruvaldehyde/toxicity , Reactive Oxygen Species/metabolism , Signal Transduction/drug effects
17.
J Clin Med ; 13(12)2024 Jun 13.
Article in English | MEDLINE | ID: mdl-38929995

ABSTRACT

Nanoengineering has emerged as a progressive method in cancer treatment, offering precise and targeted delivery of therapeutic agents while concurrently reducing overall toxicity. This scholarly article delves into the innovative strategies and advancements in nanoengineering that bridge the gap between clinical practice and research in the field of cancer treatment. Various nanoengineered platforms such as nanoparticles, liposomes, and dendrimers are scrutinized for their capacity to encapsulate drugs, augment drug efficacy, and enhance pharmacokinetics. Moreover, the article investigates research breakthroughs that drive the progression and enhancement of nanoengineered remedies, encompassing the identification of biomarkers, establishment of preclinical models, and advancement of biomaterials, all of which are imperative for translating laboratory findings into practical medical interventions. Furthermore, the integration of nanotechnology with imaging modalities, which amplify cancer detection, treatment monitoring, and response assessment, is thoroughly examined. Finally, the obstacles and prospective directions in nanoengineering, including regulatory challenges and issues related to scalability, are examined. This underscores the significance of fostering collaboration among various entities in order to efficiently translate nanoengineered interventions into enhanced cancer therapies and patient management.

18.
J Clin Med ; 13(14)2024 Jul 18.
Article in English | MEDLINE | ID: mdl-39064229

ABSTRACT

The leading cause of cancer deaths worldwide is attributed to non-small cell lung cancer (NSCLC), necessitating a continual focus on improving the diagnosis and treatment of this disease. In this review, the latest breakthroughs and emerging trends in managing NSCLC are highlighted. Major advancements in diagnostic methods, including better imaging technologies and the utilization of molecular biomarkers, are discussed. These advancements have greatly enhanced early detection and personalized treatment plans. Significant improvements in patient outcomes have been achieved by new targeted therapies and immunotherapies, providing new hope for individuals with advanced NSCLC. This review discusses the persistent challenges in accessing advanced treatments and their associated costs despite recent progress. Promising research into new therapies, such as CAR-T cell therapy and oncolytic viruses, which could further revolutionize NSCLC treatment, is also highlighted. This review aims to inform and inspire continued efforts to improve outcomes for NSCLC patients globally, by offering a comprehensive overview of the current state of NSCLC treatment and future possibilities.

19.
Cancers (Basel) ; 16(13)2024 Jul 07.
Article in English | MEDLINE | ID: mdl-39001539

ABSTRACT

The rise of drug resistance in cancer cells presents a formidable challenge in modern oncology, necessitating the exploration of innovative therapeutic strategies. This review investigates the latest advancements in overcoming drug resistance mechanisms employed by cancer cells, focusing on emerging therapeutic modalities. The intricate molecular insights into drug resistance, including genetic mutations, efflux pumps, altered signaling pathways, and microenvironmental influences, are discussed. Furthermore, the promising avenues offered by targeted therapies, combination treatments, immunotherapies, and precision medicine approaches are highlighted. Specifically, the synergistic effects of combining traditional cytotoxic agents with molecularly targeted inhibitors to circumvent resistance pathways are examined. Additionally, the evolving landscape of immunotherapeutic interventions, including immune checkpoint inhibitors and adoptive cell therapies, is explored in terms of bolstering anti-tumor immune responses and overcoming immune evasion mechanisms. Moreover, the significance of biomarker-driven strategies for predicting and monitoring treatment responses is underscored, thereby optimizing therapeutic outcomes. For insights into the future direction of cancer treatment paradigms, the current review focused on prevailing drug resistance challenges and improving patient outcomes, through an integrative analysis of these emerging therapeutic strategies.

20.
Biochim Biophys Acta Rev Cancer ; 1879(3): 189106, 2024 May.
Article in English | MEDLINE | ID: mdl-38701936

ABSTRACT

Cervical cancer remains a significant global health burden, necessitating innovative approaches for improved diagnostics and personalized treatment strategies. Precision medicine has emerged as a promising paradigm, leveraging biomarkers and molecular targets to tailor therapy to individual patients. This review explores the landscape of emerging biomarkers and molecular targets in cervical cancer, highlighting their potential implications for precision medicine. By integrating these biomarkers into comprehensive diagnostic algorithms, clinicians can identify high-risk patients at an earlier stage, enabling timely intervention and improved patient outcomes. Furthermore, the identification of specific molecular targets has paved the way for the development of targeted therapies aimed at disrupting key pathways implicated in cervical carcinogenesis. In conclusion, the evolving landscape of biomarkers and molecular targets presents exciting opportunities for advancing precision medicine in cervical cancer. By harnessing these insights, clinicians can optimize treatment selection, enhance patient outcomes, and ultimately transform the management of this devastating disease.


Subject(s)
Biomarkers, Tumor , Molecular Targeted Therapy , Precision Medicine , Uterine Cervical Neoplasms , Humans , Uterine Cervical Neoplasms/genetics , Uterine Cervical Neoplasms/drug therapy , Uterine Cervical Neoplasms/pathology , Uterine Cervical Neoplasms/metabolism , Uterine Cervical Neoplasms/diagnosis , Biomarkers, Tumor/genetics , Biomarkers, Tumor/metabolism , Female , Molecular Targeted Therapy/methods
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