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Molecularly targeted cancer therapies substantially improve patient outcomes, although the durability of their effectiveness can be limited. Resistance to these therapies is often related to adaptive changes in the target oncoprotein which reduce binding affinity. The arsenal of targeted cancer therapies, moreover, lacks coverage of several notorious oncoproteins with challenging features for inhibitor development. Degraders are a relatively new therapeutic modality which deplete the target protein by hijacking the cellular protein destruction machinery. Degraders offer several advantages for cancer therapy including resiliency to acquired mutations in the target protein, enhanced selectivity, lower dosing requirements, and the potential to abrogate oncogenic transcription factors and scaffolding proteins. Herein, we review the development of proteolysis targeting chimeras (PROTACs) for selected cancer therapy targets and their reported biological activities. The medicinal chemistry of PROTAC design has been a challenging area of active research, but the recent advances in the field will usher in an era of rational degrader design.
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Neoplasias , Proteínas Oncogénicas , Humanos , Proteolisis , Proteínas Oncogénicas/metabolismo , Factores de Transcripción/metabolismo , Ubiquitina-Proteína Ligasas/metabolismo , Neoplasias/tratamiento farmacológico , Neoplasias/genéticaRESUMEN
There is a need to improve response rates of immunotherapies in lung adenocarcinoma (AC). Extended (7-14 days) treatment of high glucocorticoid receptor (GR) expressing lung AC cells with dexamethasone (Dex) induces an irreversible senescence phenotype through chronic induction of p27. As the senescence-associated secretory phenotype (SASP) may have either tumor supporting or antitumor immunomodulatory effects, it was interest to examine the effects of Dex-induced senescence of lung AC cells on immune cells. Dex-induced senescence resulted in sustained production of CCL2, CCL4, CXCL1 and CXCL2, both in vitro and in vivo. After Dex withdrawal, secretion of these chemokines by the senescent cells attracted peripheral blood monocytes, T-cells, and NK cells. Following treatment with Dex-induced SASP protein(s), the peripheral blood lymphocytes exhibited higher cell count and tumor cytolytic activity along with enhanced Ki67 and perforin expression in T and NK cells. This cytolytic activity was partially attributed to NKG2D, which was upregulated in NK cells by SASP while its ligand MICA/B was upregulated in the senescent cells. Enhanced infiltrations of T and NK cells were observed in human lung AC xenografts in humanized NSG mice, following treatment with Dex. The findings substantiate the idea that induction of irreversible senescence in high-GR expressing subpopulations of lung AC tumors using Dex pretreatment enhances tumor immune infiltration and may subsequently improve the clinical outcome of current immunotherapies.
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Adenocarcinoma del Pulmón , Neoplasias Pulmonares , Humanos , Animales , Ratones , Dexametasona/farmacología , Adenocarcinoma del Pulmón/tratamiento farmacológico , Neoplasias Pulmonares/metabolismo , Células Asesinas Naturales/metabolismo , Senescencia Celular/genéticaRESUMEN
DNA-dependent protein kinase (DNA-PK) plays a critical role in the non-homologous end joining (NHEJ) repair pathway and the DNA damage response (DDR). DNA-PK has therefore been pursued for the development of anti-cancer therapeutics in combination with ionizing radiation (IR). We report the discovery of a new class of DNA-PK inhibitors that act via a novel mechanism of action, inhibition of the Ku-DNA interaction. We have developed a series of highly potent and specific Ku-DNA binding inhibitors (Ku-DBi's) that block the Ku-DNA interaction and inhibit DNA-PK kinase activity. Ku-DBi's directly interact with the Ku and inhibit in vitro NHEJ, cellular NHEJ, and potentiate the cellular activity of radiomimetic agents and IR. Analysis of Ku-null cells demonstrates that Ku-DBi's cellular activity is a direct result of Ku inhibition, as Ku-null cells are insensitive to Ku-DBi's. The utility of Ku-DBi's was also revealed in a CRISPR gene-editing model where we demonstrate that the efficiency of gene insertion events was increased in cells pre-treated with Ku-DBi's, consistent with inhibition of NHEJ and activation of homologous recombination to facilitate gene insertion. These data demonstrate the discovery and application of new series of compounds that modulate DNA repair pathways via a unique mechanism of action.
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Reparación del ADN por Unión de Extremidades/efectos de los fármacos , Proteína Quinasa Activada por ADN/antagonistas & inhibidores , Autoantígeno Ku/antagonistas & inhibidores , Inhibidores de Proteínas Quinasas/farmacología , Animales , Células Cultivadas , ADN/química , Roturas del ADN de Doble Cadena , Edición Génica , Humanos , Autoantígeno Ku/química , Ratones , Inhibidores de Proteínas Quinasas/químicaRESUMEN
Xanthine oxidase (XO) has been primarily targeted for the development of anti-hyperuriciemic /anti-gout agents as it catalyzes the conversion of xanthine and hypoxanthine into uric acid. XO overexpression in various cancer is very well correlated due to reactive oxygen species (ROS) production and metabolic activation of carcinogenic substances during the catalysis. Herein, we report the design and synthesis of a series of 3,5-diaryl-4,5-dihydro-1H-pyrazole carbaldehyde derivatives (2a-2x) as xanthine oxidase inhibitors (XOIs). A docking model was developed for the prediction of XO inhibitory activity of our novel compounds. Furthermore, our compounds anticancer activity results in low XO expression and XO-harboring cancer cells both in 2D and 3D-culture models are presented and discussed. Among the array of synthesized compounds, 2b and 2m emerged as potent XO inhibitors having IC50 values of 9.32 ± 0.45 µM and 10.03 ± 0.43 µM, respectively. Both compounds induced apoptosis, halted the cell cycle progression at the G1 phase, elevated ROS levels, altered mitochondrial membrane potential, and inhibited antioxidant enzymes. The levels of miRNA and expression of redox sensors in cells were also altered due to increase oxidative stress induced by our compounds. Compounds 2b and 2m hold a great promise for further development of XOIs for the treatment of XO-harboring tumors.
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Diseño de Fármacos , Inhibidores Enzimáticos/síntesis química , Pirazoles/química , Xantina Oxidasa/metabolismo , Aldehídos/química , Apoptosis/efectos de los fármacos , Sitios de Unión , Dominio Catalítico , Línea Celular Tumoral , Inhibidores Enzimáticos/metabolismo , Inhibidores Enzimáticos/farmacología , Puntos de Control de la Fase G1 del Ciclo Celular/efectos de los fármacos , Humanos , Cinética , Potencial de la Membrana Mitocondrial , MicroARNs/metabolismo , Simulación del Acoplamiento Molecular , Estrés Oxidativo/efectos de los fármacos , Oxidorreductasas/antagonistas & inhibidores , Oxidorreductasas/metabolismo , Pirazoles/metabolismo , Pirazoles/farmacología , Relación Estructura-Actividad Cuantitativa , Especies Reactivas de Oxígeno/metabolismo , Xantina Oxidasa/antagonistas & inhibidoresRESUMEN
Cdc7 is a serine-threonine kinase that phosphorylates components of the pre-replication complex during DNA replication initiation. Cdc7 is highly conserved, and Cdc7 orthologs have been characterized in organisms ranging from yeast to humans. Cdc7 is activated specifically during late G1/S phase by binding to its regulatory subunit, Dbf4. Drosophila melanogaster contains a Dbf4 ortholog, Chiffon, which is essential for chorion amplification in Drosophila egg chambers. However, no Drosophila ortholog of Cdc7 has yet been characterized. Here, we report the functional and biochemical characterization of a Drosophila ortholog of Cdc7. Co-expression of Drosophila Cdc7 and Chiffon is able to complement a growth defect in yeast containing a temperature-sensitive Cdc7 mutant. Cdc7 and Chiffon physically interact and can be co-purified from insect cells. Cdc7 phosphorylates the known Cdc7 substrates Mcm2 and histone H3 in vitro, and Cdc7 kinase activity is stimulated by Chiffon and inhibited by the Cdc7-specific inhibitor XL413. Drosophila egg chamber follicle cells deficient for Cdc7 have a defect in two types of DNA replication, endoreplication and chorion gene amplification. However, follicle cells deficient for Chiffon have a defect in chorion gene amplification but still undergo endocycling. Our results show that Cdc7 interacts with Chiffon to form a functional Dbf4-dependent kinase complex and that Cdc7 is necessary for DNA replication in Drosophila egg chamber follicle cells. Additionally, we show that Chiffon is a member of an expanding subset of DNA replication initiation factors that are not strictly required for endoreplication in Drosophila.
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Replicación del ADN , Proteínas de Drosophila/metabolismo , Proteínas del Huevo/metabolismo , Regulación de la Expresión Génica , Proteínas Serina-Treonina Quinasas/metabolismo , Alelos , Secuencia de Aminoácidos , Animales , Ciclo Celular , Clonación Molecular , Cruzamientos Genéticos , Proteínas de Drosophila/genética , Proteínas del Huevo/genética , Femenino , Histonas/química , Humanos , Masculino , Ratones , Datos de Secuencia Molecular , Mutagénesis , Mutación , Fosforilación , Filogenia , Proteínas Serina-Treonina Quinasas/genética , Proteínas Recombinantes , Saccharomyces cerevisiae , Schizosaccharomyces , Homología de Secuencia de Aminoácido , TemperaturaRESUMEN
The cellular entry of HIV-1 into CD4(+) T cells requires ordered interactions of HIV-1 envelope glycoprotein with C-X-C chemokine receptor type 4 (CXCR4) receptors. However, such interactions, which should be critical for rational structure-based discovery of new CXCR4 inhibitors, remain poorly understood. Here we first determined the effects of amino acid substitutions in CXCR4 on HIV-1NL 4 - 3 glycoprotein-elicited fusion events using site-directed mutagenesis-based fusion assays and identified 11 potentially key amino acid substitutions, including D97A and E288A, which caused >30% reductions in fusion. We subsequently carried out a computational search of a screening library containing â¼604,000 compounds, in order to identify potential CXCR4 inhibitors. The computational search used the shape of IT1t, a known CXCR4 inhibitor, as a reference and employed various algorithms, including shape similarity, isomer generation, and docking against a CXCR4 crystal structure. Sixteen small molecules were identified for biological assays based on their high shape similarity to IT1t, and their putative binding modes formed hydrogen bond interactions with the amino acids identified above. Three compounds with piperidinylethanamine cores showed activity and were resynthesized. One molecule, designated CX6, was shown to significantly inhibit fusion elicited by X4 HIV-1NL 4 - 3 glycoprotein (50% inhibitory concentration [IC50], 1.9 µM), to inhibit Ca(2+) flux elicited by stromal cell-derived factor 1α (SDF-1α) (IC50, 92 nM), and to exert anti-HIV-1 activity (IC50, 1.5 µM). Structural modeling demonstrated that CX6 bound to CXCR4 through hydrogen bond interactions with Asp97 and Glu288. Our study suggests that targeting CXCR4 residues important for fusion elicited by HIV-1 envelope glycoprotein should be a useful and feasible approach to identifying novel CXCR4 inhibitors, and it provides important insights into the mechanism by which small-molecule CXCR4 inhibitors exert their anti-HIV-1 activities.
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Fármacos Anti-VIH/síntesis química , Fármacos Anti-VIH/farmacología , Inhibidores de Fusión de VIH/síntesis química , Inhibidores de Fusión de VIH/farmacología , VIH-1/efectos de los fármacos , Piperidinas/síntesis química , Piperidinas/farmacología , Receptores CXCR4/antagonistas & inhibidores , Algoritmos , Sustitución de Aminoácidos , Supervivencia Celular/efectos de los fármacos , Ensayos Analíticos de Alto Rendimiento , Humanos , Enlace de Hidrógeno , Mutagénesis Sitio-Dirigida , Receptores CXCR4/química , Bibliotecas de Moléculas Pequeñas , Proteínas del Envoltorio Viral/metabolismoRESUMEN
Coronavirus disease 2019 (COVID-19) was declared a global pandemic in March 2020, which precipitated urgent public health responses. The causative agent, SARS-CoV-2, spreads primarily via respiratory droplets, necessitating precautions to mitigate transmission risks. Biopharmaceutical industries and academic institutions worldwide swiftly redirected their research endeavors towards developing therapeutic interventions, focusing on monoclonal antibodies, antiviral agents, and immunomodulatory therapies. The evolving body of evidence surrounding these treatments has prompted successive updates and revisions from the FDA, delineating the evolving landscape of COVID-19 therapeutics. This review comprehensively examines each treatment modality within the context of their developmental trajectories and regulatory approvals throughout the pandemic. Furthermore, it elucidates their mechanisms of action and presents clinical data underpinning their utility in combating the COVID-19 crisis.
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Antivirales , Tratamiento Farmacológico de COVID-19 , COVID-19 , Desarrollo de Medicamentos , SARS-CoV-2 , Humanos , Antivirales/farmacología , Antivirales/uso terapéutico , SARS-CoV-2/efectos de los fármacos , Desarrollo de Medicamentos/métodos , Anticuerpos Monoclonales/uso terapéutico , Anticuerpos Monoclonales/farmacología , Agentes Inmunomoduladores/farmacología , Agentes Inmunomoduladores/uso terapéutico , Animales , PandemiasRESUMEN
Zika virus (ZIKV) is a re-emerging RNA virus that is known to cause ocular and neurological abnormalities in infants. ZIKV exploits autophagic processes in infected cells to enhance its replication and spread. Thus, autophagy inhibitors have emerged as a potent therapeutic target to combat RNA viruses, with Hydroxychloroquine (HCQ) being one of the most promising candidates. In this study, we synthesized several novel small-molecule quinoline derivatives, assessed their antiviral activity, and determined the underlying molecular mechanisms. Among the nine synthesized analogs, two lead candidates, labeled GL-287 and GL-382, significantly attenuated ZIKV replication in human ocular cells, primarily by inhibiting autophagy. These two compounds surpassed the antiviral efficacy of HCQ and other existing autophagy inhibitors, such as ROC-325, DC661, and GNS561. Moreover, unlike HCQ, these novel analogs did not exhibit cytotoxicity in the ocular cells. Treatment with compounds GL-287 and GL-382 in ZIKV-infected cells increased the abundance of LC3 puncta, indicating the disruption of the autophagic process. Furthermore, compounds GL-287 and GL-382 effectively inhibited the ZIKV-induced innate inflammatory response in ocular cells. Collectively, our study demonstrates the safe and potent antiviral activity of novel autophagy inhibitors against ZIKV.
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Antivirales , Autofagia , Quinolinas , Replicación Viral , Infección por el Virus Zika , Virus Zika , Virus Zika/efectos de los fármacos , Virus Zika/fisiología , Autofagia/efectos de los fármacos , Replicación Viral/efectos de los fármacos , Humanos , Antivirales/farmacología , Antivirales/síntesis química , Antivirales/química , Quinolinas/farmacología , Quinolinas/química , Quinolinas/síntesis química , Infección por el Virus Zika/tratamiento farmacológico , Infección por el Virus Zika/virología , Línea Celular , Chlorocebus aethiops , Animales , Células VeroRESUMEN
Background: DNA-dependent protein kinase (DNA-PK) is a validated cancer therapeutic target involved in DNA damage response (DDR) and non-homologous end-joining (NHEJ) repair of DNA double-strand breaks (DSBs). Ku serves as a sensor of DSBs by binding to DNA ends and activating DNA-PK. Inhibition of DNA-PK is a common strategy to block DSB repair and improve efficacy of ionizing radiation (IR) therapy and radiomimetic drug therapies. We have previously developed Ku-DNA binding inhibitors (Ku-DBis) that block in vitro and cellular NHEJ activity, abrogate DNA-PK autophosphorylation, and potentiate cellular sensitivity to IR. Results and Conclusions: Here we report the discovery of oxindole Ku-DBis with improved cellular uptake and retained potent Ku-inhibitory activity. Variable monotherapy activity was observed in a panel of non-small cell lung cancer (NSCLC) cell lines, with ATM-null cells being the most sensitive and showing synergy with IR. BRCA1-deficient cells were resistant to single-agent treatment and antagonistic when combined with DSB-generating therapies. In vivo studies in an NSCLC xenograft model demonstrated that the Ku-DBi treatment blocked IR-dependent DNA-PKcs autophosphorylation, modulated DDR, and reduced tumor cell proliferation. This represents the first in vivo demonstration of a Ku-targeted DNA-binding inhibitor impacting IR response and highlights the potential therapeutic utility of Ku-DBis for cancer treatment.
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Twenty three dual PPARα and γ molecules of natural product origin, previously reported by our group, were further investigated for pan PPAR transactivation against PPARδ. The in vitro cell toxicity profile, as well as, in silico study of the most active molecules within this new class of pan PPAR agonists are also described. 3',5' Dimethoxy-7 hydroxyisoflavone 6, Ψ-baptigenin 7, 4' fluoro-7 hydroxyisoflavone 8, and 3' methoxy-7 hydroxyisoflavone 9 were identified as the most potent molecules studied within the set compared to the commercially available pan PPAR agonist, bezafibrate 1. These novel active molecules may thus be useful as future leads in PPAR-related disorders, including type II diabetes mellitus and metabolic syndrome.
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Descubrimiento de Drogas , Isoflavonas/farmacología , Receptores Activados del Proliferador del Peroxisoma/agonistas , Proliferación Celular/efectos de los fármacos , Supervivencia Celular/efectos de los fármacos , Relación Dosis-Respuesta a Droga , Células HEK293 , Humanos , Isoflavonas/síntesis química , Isoflavonas/química , Modelos Moleculares , Estructura Molecular , Relación Estructura-ActividadRESUMEN
Current treatment strategies for triple-negative breast cancer (TNBC) are based upon conventional chemotherapy, immunotherapy, or a combination of both. The treatment regimen for chemotherapy is often a combination of two or more drugs, either dose dense or low dose for synergy. Anthracyclines, alkylating agents, antimicrotubule agents, and antimetabolites for early-stage TNBC; and antimetabolites, non-taxane microtubule inhibitors, and cross-linker platinums for late-stage TNBC are usually administered in the clinical setting. Newer options for patients with advanced TNBC, such as poly (ADP-ribose) polymerase (PARP) inhibitors and immune checkpoint inhibitors, have recently emerged for cases where surgery is not a viable option and the disease has metastasized. This review outlines the current trends in hypoxia-inspired treatment strategies for TNBC with a focus on clinical trials.
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Neoplasias de la Mama Triple Negativas , Humanos , Neoplasias de la Mama Triple Negativas/terapia , Inhibidores de Poli(ADP-Ribosa) Polimerasas , Inmunoterapia , Antimetabolitos/uso terapéuticoRESUMEN
The DNA-dependent protein kinase (DNA-PK) plays a critical role in the DNA damage response (DDR) and non-homologous end joining (NHEJ) double-strand break (DSB) repair pathways. Consequently, DNA-PK is a validated therapeutic target for cancer treatment in certain DNA repair-deficient cancers and in combination with ionizing radiation (IR). We have previously reported the discovery and development of a novel class of DNA-PK inhibitors with a unique mechanism of action, blocking the Ku 70/80 heterodimer interaction with DNA. These Ku-DNA binding inhibitors (Ku-DBi's) display nanomolar activity in vitro, inhibit cellular DNA-PK, NHEJ-catalyzed DSB repair and sensitize non-small cell lung cancer (NSCLC) cells to DSB-inducing agents. In this study, we demonstrate that chemical inhibition of the Ku-DNA interaction potentiates the cellular effects of bleomycin and IR via p53 phosphorylation through the activation of the ATM pathway. This response is concomitant with a reduction of DNA-PK catalytic subunit (DNA-PKcs) autophosphorylation at S2056 and a time-dependent increase in H2AX phosphorylation at S139. These results are consistent with Ku-DBi's abrogating DNA-PKcs autophosphorylation to impact DSB repair and DDR signaling through a novel mechanism of action, and thus represent a promising anticancer therapeutic strategy in combination with DNA DSB-inducing agents.
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Epidermal growth factor receptor (EGFR) is an oncogenic drug target and plays a critical role in several cellular functions including cancer cell growth, survival, proliferation, differentiation, and motility. Several small-molecule tyrosine kinase inhibitors (TKIs) and monoclonal antibodies (mAbs) have been approved for targeting intracellular and extracellular domains of EGFR, respectively. However, cancer heterogeneity, mutations in the catalytic domain of EGFR, and persistent drug resistance limited their use. Different novel modalities are gaining a position in the limelight of anti-EGFR therapeutics to overcome such limitations. The current perspective reflects upon newer modalities, importantly the molecular degraders such as PROTACs, LYTACs, AUTECs, and ATTECs, etc., beginning with a snapshot of traditional and existing anti-EGFR therapies including small molecule inhibitors, mAbs, and antibody drug conjugates (ADCs). Further, a special emphasis has been made on the design, synthesis, successful applications, state-of-the-art, and emerging future opportunities of each discussed modality.
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Antineoplásicos , Neoplasias , Humanos , Antineoplásicos/farmacología , Antineoplásicos/uso terapéutico , Inhibidores de Proteínas Quinasas/farmacología , Inhibidores de Proteínas Quinasas/uso terapéutico , Receptores ErbB/metabolismo , Anticuerpos Monoclonales/uso terapéutico , Anticuerpos Monoclonales/farmacología , Neoplasias/tratamiento farmacológicoRESUMEN
During a cytokine storm, dysregulated proinflammatory cytokines are produced in excess. Cytokine storms occur in multiple infectious diseases, including Coronavirus 2019 (COVID-19). Thus, eliminating cytokine storms to enhance patient outcomes is crucial. Given the numerous cytokines involved, individual therapies might have little effect. Traditional cytokines might be less effective than medicines that target malfunctioning macrophages. Nanomedicine-based therapeutics reduce cytokine production in animal models of proinflammatory illnesses. The unique physicochemical features and controlled nano-bio interactions of nanotechnology show promise in healthcare and could be used to treat several stages of this virus-induced sickness, including cytokine storm mortality. Macrophage-oriented nanomedicines can minimize cytokine storms and associated harmful effects, enhancing patient outcomes. Here, we also discuss engineering possibilities for enhancing macrophage efficacy with nanodrug carriers.
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Cardiac glycosides (CGs) are bioactive compounds originally used to treat heart diseases, but recent studies have demonstrated their anticancer activity. We previously demonstrated that Antiaris toxicaria 2 (AT2) possesses anticancer activity in KRAS mutated lung cancers via impinging on the DNA damage response (DDR) pathway. Toward developing this class of molecules for cancer therapy, herein we report a multistep synthetic route utilizing k-strophanthidin as the initial building block for determination of structure-activity relationships (SARs). A systematic structural design approach was applied that included modifications of the sugar moiety, the glycoside linker, stereochemistry, and lactone ring substitutions to generate a library of O-glycosides and MeON-neoglycosides derivatives. These molecules were screened for their anticancer activities and their impact on DDR signaling in KRAS mutant lung cancer cells. These results demonstrate the ability to chemically synthesize CG derivatives and define the SARs to optimize AT2 as a cancer therapeutic.
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Antiaris , Antineoplásicos , Glicósidos Cardíacos , Neoplasias Pulmonares , Humanos , Glicósidos Cardíacos/farmacología , Glicósidos Cardíacos/química , Proteínas Proto-Oncogénicas p21(ras)/genética , Antiaris/química , Relación Estructura-Actividad , Neoplasias Pulmonares/tratamiento farmacológico , Daño del ADN , Glicósidos/farmacología , Antineoplásicos/químicaRESUMEN
Pancreatic cancer is the second leading cause of cancer-related death in the USA. The 5-year survival rate for pancreatic cancer is as low as 10%, making it one of the most deadly cancers. This dismal prognosis is caused, in part, by the lack of early detection and screening options, leading to late-stage detection of the disease, at a point at which chemotherapy is no longer effective. However, nanoparticle (NP) drug delivery systems have increased the efficacy of chemotherapeutics by improving the targeting ability of drugs to the tumor site, while also decreasing the risk of local and systemic toxicity. Such efforts can contribute to the development of early diagnosis and routine screening tests, which will drastically improve the survival rates and prognosis of patients with pancreatic cancer.
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Nanomedicina , Neoplasias Pancreáticas , Detección Precoz del Cáncer , Humanos , Neoplasias Pancreáticas/diagnóstico , Neoplasias Pancreáticas/tratamiento farmacológico , Preparaciones Farmacéuticas , Neoplasias PancreáticasRESUMEN
Replication protein A (RPA) plays essential roles in DNA replication, repair, recombination, and the DNA damage response (DDR). Retrospective analysis of lung cancer patient data demonstrates high RPA expression as a negative prognostic biomarker for overall survival in smoking-related lung cancers. Similarly, relative expression of RPA is a predictive marker for response to chemotherapy. These observations are consistent with the increase in RPA expression serving as an adaptive mechanism that allows tolerance of the genotoxic stress resulting from carcinogen exposure. We have developed second-generation RPA inhibitors (RPAis) that block the RPA-DNA interaction and optimized formulation for in vivo analyses. Data demonstrate that unlike first-generation RPAis, second-generation molecules show increased cellular permeability and induce cell death via apoptosis. Second-generation RPAis elicit single-agent in vitro anticancer activity across a broad spectrum of cancers, and the cellular response suggests existence of a threshold before chemical RPA exhaustion induces cell death. Chemical RPA inhibition potentiates the anticancer activity of a series of DDR inhibitors and traditional DNA-damaging cancer therapeutics. Consistent with chemical RPA exhaustion, we demonstrate that the effects of RPAi on replication fork dynamics are similar to other known DDR inhibitors. An optimized formulation of RPAi NERx 329 was developed that resulted in single-agent anticancer activity in two non-small cell lung cancer models. These data demonstrate a unique mechanism of action of RPAis eliciting a state of chemical RPA exhaustion and suggest they will provide an effective therapeutic option for difficult-to-treat lung cancers.
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The vast majority of cancer patients receive DNA-damaging drugs or ionizing radiation (IR) during their course of treatment, yet the efficacy of these therapies is tempered by DNA repair and DNA damage response (DDR) pathways. Aberrations in DNA repair and the DDR are observed in many cancer subtypes and can promote de novo carcinogenesis, genomic instability, and ensuing resistance to current cancer therapy. Additionally, stalled or collapsed DNA replication forks present a unique challenge to the double-strand DNA break (DSB) repair system. Of the various inducible DNA lesions, DSBs are the most lethal and thus desirable in the setting of cancer treatment. In mammalian cells, DSBs are typically repaired by the error prone non-homologous end joining pathway (NHEJ) or the high-fidelity homology directed repair (HDR) pathway. Targeting DSB repair pathways using small molecular inhibitors offers a promising mechanism to synergize DNA-damaging drugs and IR while selective inhibition of the NHEJ pathway can induce synthetic lethality in HDR-deficient cancer subtypes. Selective inhibitors of the NHEJ pathway and alternative DSB-repair pathways may also see future use in precision genome editing to direct repair of resulting DSBs created by the HDR pathway. In this review, we highlight the recent advances in the development of inhibitors of the non-phosphatidylinositol 3-kinase-related kinases (non-PIKKs) members of the NHEJ, HDR and minor backup SSA and alt-NHEJ DSB-repair pathways. The inhibitors described within this review target the non-PIKKs mediators of DSB repair including Ku70/80, Artemis, DNA Ligase IV, XRCC4, MRN complex, RPA, RAD51, RAD52, ERCC1-XPF, helicases, and DNA polymerase θ. While the DDR PIKKs remain intensely pursued as therapeutic targets, small molecule inhibition of non-PIKKs represents an emerging opportunity in drug discovery that offers considerable potential to impact cancer treatment.
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Lung cancer is the leading cause of cancer death among both men and women in the United States. Because lung cancer is genetically heterogeneous, tailored therapy alone or in combination with chemotherapy would increase patient overall survival as compared with the one-size-fits-all chemotherapy. TP53-mutant lung cancer accounts for more than half of all lung cancer cases and is oftentimes more aggressive and resistant to chemotherapy. Directly targeting mutant p53 has not yet been successful, so identification of novel therapy targets and biomarkers in the TP53-mutant lung cancer is urgently needed to increase the overall survival in this subgroup. Deubiquitinating enzymes (DUBs) regulate a vast majority of proteins (DUBs' substrates) via removal of ubiquitin moieties or ubiquitin chains from these proteins, thereby altering the stability and/or functions of these substrates. In this review, we will focus on a DUB, referred to as ubiquitin-specific peptidase 10 (USP10) whose substrates include both oncogenic proteins and tumor suppressors. Therefore, targeting USP10 in cancer is highly context-dependent. Here, we will discuss USP10's functions in cancer by examining its various known substrates. In particular, we will elaborate our recent findings in the oncogenic role of USP10 in the TP53-mutant subgroup of lung cancer, focusing on USP10's function in the DNA damage response (DDR) via histone deacetylase 6 (HDAC6). Overall, these findings support the notion that targeting USP10 in the TP53-mutant subgroup of NSCLC would sensitize patients to cisplatin-based chemotherapy. Generating potent and specific clinically relevant USP10 inhibitors would benefit the TP53-mutant subgroup of NSCLC patients.
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Pro-inflammatory cytokine and chemokines genes drive prostate cancer progression and metastasis: molecular mechanism update and the science that underlies racial disparity. comprehensive review article. Isaac J. Powell, S. Chinni, S.S. Reddy, Alexander Zaslavsky, Navnath Gavande Introduction: In 2013 we reported that with the use of bioinformatics and ingenuity pathway network analysis we were able to identify functional driver genes that were differentially expressed among a large population of African American men (AAM) and European American men (EAM). Pro-inflammatory cytokine genes were found to be more interactive and more expressed among AAM and have been found to be functional drivers of aggressive prostate cancer (CaP) and aggressiveness in other solid tumors. We examined these genes and biological pathways initiated by these cytokines in primary CaP tissue. Method We unravel the gene network and identified biologic pathways that impacted activation of the androgen receptor, mesenchymal epithelial transition (invasion) and chemokines associated with metastasis in the CaP tissue from 639 radical prostatectomy specimens. Results Biologic pathways identified by unraveling pro-inflammatory genes from our network, more expressed among AAM compared to EAM, were tumor necrosis factor (TNF), IL1b, IL6, and IL8. IL6 and IL8 are downstream of TNF activity and are known activators of androgen receptor and through mediators promote CaP cell proliferation. TNF and IL1b mediate tumor cell invasiveness through the activation of MMP (matrix metalloproteinase) which down regulates E-Cadherin to initiate epithelial mesenchymal transition which allows cells to become invasive in the microenvironment. Ultimately our network analysis indicates that TNF and IL1b activate CXCR4 receptor on CaP cells, which facilitates metastatic progression reportedly by binding to CXCL12 on lipid rafts and tumor implantation in the bone marrow. Conclusion Our retrospective biologic mechanistic model reveals a set of pro-inflammatory cytokines and chemokines that drive CaP aggressiveness, tumor heterogeneity, progression and metastasis. A prospective multi-institutional study needs to be conducted for clinical validation as well consideration of targeted therapy.