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1.
Mol Cell Proteomics ; 17(5): 925-947, 2018 05.
Artigo em Inglês | MEDLINE | ID: mdl-29496907

RESUMO

SRMS (Src-related kinase lacking C-terminal regulatory tyrosine and N-terminal myristoylation sites), also known as PTK 70 (Protein tyrosine kinase 70), is a non-receptor tyrosine kinase that belongs to the BRK family of kinases (BFKs). To date less is known about the cellular role of SRMS primarily because of the unidentified substrates or signaling intermediates regulated by the kinase. In this study, we used phosphotyrosine antibody-based immunoaffinity purification in large-scale label-free quantitative phosphoproteomics to identify novel candidate substrates of SRMS. Our analyses led to the identification of 1258 tyrosine-phosphorylated peptides which mapped to 663 phosphoproteins, exclusively from SRMS-expressing cells. DOK1, a previously characterized SRMS substrate, was also identified in our analyses. Functional enrichment analyses revealed that the candidate SRMS substrates were enriched in various biological processes including protein ubiquitination, mitotic cell cycle, energy metabolism and RNA processing, as well as Wnt and TNF signaling. Analyses of the sequence surrounding the phospho-sites in these proteins revealed novel candidate SRMS consensus substrate motifs. We utilized customized high-throughput peptide arrays to validate a subset of the candidate SRMS substrates identified in our MS-based analyses. Finally, we independently validated Vimentin and Sam68, as bona fide SRMS substrates through in vitro and in vivo assays. Overall, our study identified a number of novel and biologically relevant SRMS candidate substrates, which suggests the involvement of the kinase in a vast array of unexplored cellular functions.


Assuntos
Fosfoproteínas/metabolismo , Proteômica/métodos , Quinases da Família src/metabolismo , Proteínas Adaptadoras de Transdução de Sinal/metabolismo , Motivos de Aminoácidos , Sequência de Aminoácidos , Linhagem Celular , Cromatografia de Afinidade , Simulação por Computador , Sequência Consenso , Proteínas de Ligação a DNA/metabolismo , Fator de Crescimento Epidérmico/farmacologia , Humanos , Espectrometria de Massas , Fosfopeptídeos/química , Fosfopeptídeos/metabolismo , Fosforilação/efeitos dos fármacos , Fosfotirosina/metabolismo , Análise Serial de Proteínas , Proteoma/metabolismo , Proteínas de Ligação a RNA/metabolismo , Reprodutibilidade dos Testes , Especificidade por Substrato/efeitos dos fármacos , Vimentina/metabolismo , Quinases da Família src/química
2.
BMC Cancer ; 19(1): 78, 2019 Jan 16.
Artigo em Inglês | MEDLINE | ID: mdl-30651078

RESUMO

BACKGROUND: BRK is, a non-receptor tyrosine kinase, overexpressed in approximately 85% of human invasive ductal breast tumors. It is not clear whether BRK expression correlates with breast cancer subtypes, or the expression has prognostic or diagnostic significance. Herein, we investigated the correlation of BRK with any breast cancer subtypes and clinicopathological significance of BRK expression in breast cancer. METHODS: In this study, we examined BRK expression in 120 breast tumor samples and 29 breast cancer cell lines to explore the positive correlation between BRK and the expression of ERα. We used immunohistochemistry, RT-PCR, and immunoblotting to analyse our experimental samples. RESULT: We demonstrate that estrogen induces BRK gene and protein expression in ER+ breast cancer cells. Over-expression of ERα in the ER-negative breast cancer cell line increased BRK expression, and knock-down of ESR1 in MCF7 cells reduced BRK levels. Further, we provide evidence that BRK is regulated by ERα signaling and the presence of ER antagonists (tamoxifen and fulvestrant) reduce the expression of BRK in ER-positive breast cancer cells. Finally, we demonstrate that the overall survival of ER-positive breast cancer patients is poor when their cancers express high levels of BRK. CONCLUSION: Our data indicate that BRK is a prognostic marker for ER+ breast cancers and provide a strong rationale for targeting BRK to improve patients' survival.


Assuntos
Biomarcadores Tumorais/metabolismo , Neoplasias da Mama/patologia , Receptor alfa de Estrogênio/metabolismo , Proteínas de Neoplasias/metabolismo , Proteínas Tirosina Quinases/metabolismo , Mama/patologia , Neoplasias da Mama/mortalidade , Linhagem Celular Tumoral , Conjuntos de Dados como Assunto , Receptor alfa de Estrogênio/antagonistas & inibidores , Receptor alfa de Estrogênio/genética , Estrogênios/farmacologia , Feminino , Fulvestranto/farmacologia , Regulação Neoplásica da Expressão Gênica/efeitos dos fármacos , Técnicas de Silenciamento de Genes , Humanos , Transdução de Sinais/efeitos dos fármacos , Tamoxifeno/farmacologia
3.
Pestic Biochem Physiol ; 157: 161-168, 2019 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-31153464

RESUMO

Paraquat (PQ) is a widely used herbicide with no antidote which is implicated in the pathogenesis of the Parkinson's disease. The present study then investigated the potential of caffeic acid (CA), a known antioxidant, cardioprotective and neuroprotective molecule to counteract oxidative stress mediated by PQ. In addition, molecular docking was performed to understand the mechanism underlying the inhibitory effect of CA against PQ poisoning. The fruit fly, Drosophila melanogaster, was exposed to PQ (0.44 mg/g of diet) in the absence or presence of CA (0.25, 0.5, 1 and 2 mg/g of died) for 7 days. Data showed that PQ-fed flies had higher incidence of mortality which was associated with mitochondrial dysfunction, increased free Fe(II) content and lipid peroxidation when compared to the control. Co-exposure with CA reduced mortality and markedly attenuated biochemical changes induced by PQ. The mechanism investigated using molecular docking revealed a strong interaction (-6.2 Kcal/mol) of CA with D. melanogaster transcriptional activation of nuclear factor erythroid 2-related factor 2 (Nrf2). This was characterized by the binding of CA to keap-1 domain of Nrf2. Taking together these results indicate the protective effect of CA against PQ-induced oxidative damage in D. melanogaster was likely through its coordination which hinders Nrf2-keap-1 binding leading to an increase of the antioxidant defense system.


Assuntos
Ácidos Cafeicos/farmacologia , Fator 2 Relacionado a NF-E2/metabolismo , Estresse Oxidativo/efeitos dos fármacos , Paraquat/farmacologia , Animais , Drosophila melanogaster , Ferro/metabolismo , Peroxidação de Lipídeos/efeitos dos fármacos , Fator 2 Relacionado a NF-E2/genética
4.
J Biol Chem ; 292(25): 10429-10443, 2017 06 23.
Artigo em Inglês | MEDLINE | ID: mdl-28468824

RESUMO

The K-homology (KH) domain is a nucleic acid-binding domain present in many proteins but has not been reported in helicases. DDX43, also known as HAGE (helicase antigen gene), is a member of the DEAD-box protein family. It contains a helicase core domain in its C terminus and a potential KH domain in its N terminus. DDX43 is highly expressed in many tumors and is, therefore, considered a potential target for immunotherapy. Despite its potential as a therapeutic target, little is known about its activities. Here, we purified recombinant DDX43 protein to near homogeneity and found that it exists as a monomer in solution. Biochemical assays demonstrated that it is an ATP-dependent RNA and DNA helicase. Although DDX43 was active on duplex RNA regardless of the orientation of the single-stranded RNA tail, it preferred a 5' to 3' polarity on RNA and a 3' to 5' direction on DNA. Truncation mutations and site-directed mutagenesis confirmed that the KH domain in DDX43 is responsible for nucleic acid binding. Compared with the activity of the full-length protein, the C-terminal helicase domain had no unwinding activity on RNA substrates and had significantly reduced unwinding activity on DNA. Moreover, the full-length DDX43 protein, with single amino acid change in the KH domain, had reduced unwinding and binding activates on RNA and DNA substrates. Our results demonstrate that DDX43 is a dual helicase and the KH domain is required for its full unwinding activity.


Assuntos
RNA Helicases DEAD-box/química , Proteínas de Neoplasias/química , RNA de Cadeia Dupla/química , Sequência de Aminoácidos , RNA Helicases DEAD-box/genética , RNA Helicases DEAD-box/metabolismo , Humanos , Proteínas de Neoplasias/genética , Proteínas de Neoplasias/metabolismo , Domínios Proteicos , RNA de Cadeia Dupla/metabolismo , Deleção de Sequência
5.
Proteome Sci ; 16: 16, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-30140170

RESUMO

BACKGROUND: The non-receptor tyrosine kinase, SRMS (Src-related kinase lacking C-terminal regulatory tyrosine and N-terminal myristoylation sites) is a member of the BRK family kinases (BFKs) which represents an evolutionarily conserved relative of the Src family kinases (SFKs). Tyrosine kinases are known to regulate a number of cellular processes and pathways via phosphorylating substrate proteins directly and/or by partaking in signaling cross-talks leading to the indirect modulation of various signaling intermediates. In a previous study, we profiled the tyrosine-phosphoproteome of SRMS and identified multiple candidate substrates of the kinase. The broader cellular signaling intermediates of SRMS are unknown. METHODS: In order to uncover the broader SRMS-regulated phosphoproteome and identify the SRMS-regulated indirect signaling intermediates, we performed label-free global phosphoproteomics analysis on cells expressing wild-type SRMS. Using computational database searching and bioinformatics analyses we characterized the dataset. RESULTS: Our analyses identified 60 hyperphosphorylated (phosphoserine/phosphothreonine) proteins mapped from 140 hyperphosphorylated peptides. Bioinfomatics analyses identified a number of significantly enriched biological and cellular processes among which DNA repair pathways were found to be upregulated while apoptotic pathways were found to be downregulated. Analyses of motifs derived from the upregulated phosphosites identified Casein kinase 2 alpha (CK2α) as one of the major potential kinases contributing to the SRMS-dependent indirect regulation of signaling intermediates. CONCLUSIONS: Overall, our phosphoproteomics analyses identified serine/threonine phosphorylation dynamics as important secondary events of the SRMS-regulated phosphoproteome with implications in the regulation of cellular and biological processes.

6.
Int J Mol Sci ; 19(7)2018 07 08.
Artigo em Inglês | MEDLINE | ID: mdl-29986550

RESUMO

Simulated-microgravity (SMG) promotes cell-apoptosis. We demonstrated that SMG inhibited cell proliferation/metastasis via FAK/RhoA-regulated mTORC1 pathway. Since mTORC1, NF-κB, and ERK1/2 signaling are important in cell apoptosis, we examined whether SMG-enhanced apoptosis is regulated via these signals controlled by FAK/RhoA in BL6-10 melanoma cells under clinostat-modelled SMG-condition. We show that SMG promotes cell-apoptosis, alters cytoskeleton, reduces focal adhesions (FAs), and suppresses FAK/RhoA signaling. SMG down-regulates expression of mTORC1-related Raptor, pS6K, pEIF4E, pNF-κB, and pNF-κB-regulated Bcl2, and induces relocalization of pNF-κB from the nucleus to the cytoplasm. In addition, SMG also inhibits expression of nuclear envelope proteins (NEPs) lamin-A, emerin, sun1, and nesprin-3, which control nuclear positioning, and suppresses nuclear positioning-regulated pERK1/2 signaling. Moreover, rapamycin, the mTORC1 inhibitor, also enhances apoptosis in cells under 1 g condition via suppressing the mTORC1/NF-κB pathway. Furthermore, the FAK/RhoA activator, toxin cytotoxic necrotizing factor-1 (CNF1), reduces cell apoptosis, restores the cytoskeleton, FAs, NEPs, and nuclear positioning, and converts all of the above SMG-induced changes in molecular signaling in cells under SMG. Therefore, our data demonstrate that SMG reduces FAs and alters the cytoskeleton and nuclear positioning, leading to enhanced cell apoptosis via suppressing the FAK/RhoA-regulated mTORC1/NF-κB and ERK1/2 pathways. The FAK/RhoA regulatory network may, thus, become a new target for the development of novel therapeutics for humans under spaceflight conditions with stressed physiological challenges, and for other human diseases.


Assuntos
Citoesqueleto/metabolismo , MAP Quinases Reguladas por Sinal Extracelular , Adesões Focais , Simulação de Ausência de Peso/métodos , Animais , Apoptose , Núcleo Celular , Proliferação de Células , Células Cultivadas , Quinase 1 de Adesão Focal/metabolismo , Regulação da Expressão Gênica , Humanos , Alvo Mecanístico do Complexo 1 de Rapamicina/metabolismo , Camundongos , NF-kappa B/metabolismo , Proteína rhoA de Ligação ao GTP/metabolismo
7.
Cancer Metastasis Rev ; 35(2): 179-99, 2016 06.
Artigo em Inglês | MEDLINE | ID: mdl-27067725

RESUMO

The non-receptor tyrosine kinase Fyn-related kinase (FRK) is a member of the BRK family kinases (BFKs) and is distantly related to the Src family kinases (SFKs). FRK was first discovered in 1993, and studies pursued thereafter attributed a potential tumour-suppressive function to the enzyme. In recent years, however, further functional characterization of the tyrosine kinase in diverse cancer types suggests that FRK may potentially play an oncogenic role as well. Specifically, while ectopic expression of FRK suppresses cell proliferation and migration in breast and brain cancers, knockdown or catalytic inhibition of FRK suppresses these cellular processes in pancreatic and liver cancer. Such functional paradox is therefore evidently exhibited in a tissue-specific context. This review sheds light on the recent developments emerged from investigations on FRK which include: (a) a review of the expression pattern of the protein in mammalian cells/tissues, (b) underlying genomic perturbations and (c) a mechanistic function of the enzyme across different cellular environments. Given its functional heterogeneity observed across different cancers, we also discuss the therapeutic significance of FRK.


Assuntos
Proteínas de Neoplasias/genética , Proteínas de Neoplasias/metabolismo , Neoplasias/genética , Neoplasias/metabolismo , Proteínas Tirosina Quinases/genética , Proteínas Tirosina Quinases/metabolismo , Animais , Animais Geneticamente Modificados , Antineoplásicos/farmacologia , Núcleo Celular/metabolismo , Proliferação de Células , Transformação Celular Neoplásica/genética , Transformação Celular Neoplásica/metabolismo , Aberrações Cromossômicas , Modelos Animais de Doenças , Ativação Enzimática , Regulação Neoplásica da Expressão Gênica , Humanos , Terapia de Alvo Molecular , Mutação , Metástase Neoplásica , Proteínas de Neoplasias/química , Neoplasias/tratamento farmacológico , Neoplasias/patologia , Ligação Proteica , Conformação Proteica , Inibidores de Proteínas Quinases/farmacologia , Inibidores de Proteínas Quinases/uso terapêutico , Transporte Proteico , Proteínas Tirosina Quinases/química , Transdução de Sinais , Relação Estrutura-Atividade , Especificidade por Substrato , Proteínas Supressoras de Tumor/química , Proteínas Supressoras de Tumor/genética , Proteínas Supressoras de Tumor/metabolismo , Quinases da Família src/química , Quinases da Família src/genética , Quinases da Família src/metabolismo
8.
Breast Cancer Res Treat ; 166(2): 351-365, 2017 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-28776284

RESUMO

Breast cancer is the leading cause of cancer-related deaths in women worldwide. GLOBOCAN estimated about 1.7 million new cases of breast cancer diagnoses worldwide and about 522,000 deaths in 2012. The burden of breast cancer mortality lies in the developing low-income and middle-income countries, where about 70% of such deaths occur. The incidence of breast cancer is also rising in low-income and middle-income countries in Africa as trend towards urbanization, and adoption of Western lifestyles increases. In general, the triple-negative breast cancer (TNBC) subtype tends to be frequent in women of African ancestry. What are the factors contributing to this prevalence? Are there genetic predispositions to TNBC in African women? This review addresses these questions and provides an update on the incidence, survival, and mortality of breast cancer in Africans, with a focus on sub-Saharan Africans. We have also addressed factors that could account for ethical disparities in incidence and mortality. Further, we have highlighted challenges associated with access to essential drug and to healthcare treatment in some African countries and outlined alternative/herbal treatment methods that are increasingly implemented in Africa and other developing nations.


Assuntos
Proteína BRCA1/genética , Proteína BRCA2/genética , Neoplasias da Mama/epidemiologia , Neoplasias da Mama/terapia , Mortalidade , África/epidemiologia , Antineoplásicos/uso terapêutico , Neoplasias da Mama/genética , Neoplasias da Mama/mortalidade , Feminino , Predisposição Genética para Doença , Medicina Herbária , Humanos , Mastectomia , Mutação , Prevalência , Fatores Socioeconômicos
9.
Biochim Biophys Acta ; 1856(1): 39-54, 2015 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-25999240

RESUMO

Twenty years have passed since the non-receptor tyrosine kinase, Breast tumor kinase (BRK) was cloned. While BRK is evolutionarily related to the Src family kinases it forms its own distinct sub-family referred here to as the BRK family kinases. The detection of BRK in over 60% of breast carcinomas two decades ago and more remarkably, its absence in the normal mammary gland attributed to its recognition as a mammary gland-specific potent oncogene and led BRK researchers on a wild chase to characterize the role of the enzyme in breast cancer. Where has this chase led us? An increasing number of studies have been focused on understanding the cellular roles of BRK in breast carcinoma and normal tissues. A majority of such studies have proposed an oncogenic function of BRK in breast cancers. Thus far, the vast evidence gathered highlights a regulatory role of BRK in critical cellular processes driving tumor formation such as cell proliferation, migration and metastasis. Functional characterization of BRK has identified several signaling proteins that work in concert with the enzyme to sustain such a malignant phenotype. As such targeting the non-receptor tyrosine kinase has been proposed as an attractive approach towards therapeutic intervention. Yet much remains to be explored about (a) the discrepant expression levels of BRK in cancer versus normal conditions, (b) the dependence on the enzymatic activity of BRK to promote oncogenesis and (c) an understanding of the normal physiological roles of the enzyme. This review outlines the advances made towards understanding the cellular and physiological roles of BRK, the mechanisms of action of the protein and its therapeutic significance, in the context of breast cancer.


Assuntos
Neoplasias da Mama/genética , Proteínas de Neoplasias/genética , Oncogenes , Proteínas Tirosina Quinases/genética , Animais , Feminino , Perfilação da Expressão Gênica , Humanos , Camundongos , Transcriptoma
10.
R Soc Open Sci ; 11(4)2024 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-38601031

RESUMO

With the rapid development of medical imaging methods, multimodal medical image fusion techniques have caught the interest of researchers. The aim is to preserve information from diverse sensors using various models to generate a single informative image. The main challenge is to derive a trade-off between the spatial and spectral qualities of the resulting fused image and the computing efficiency. This article proposes a fast and reliable method for medical image fusion depending on multilevel Guided edge-preserving filtering (MLGEPF) decomposition rule. First, each multimodal medical image was divided into three sublayer categories using an MLGEPF decomposition scheme: small-scale component, large-scale component and background component. Secondly, two fusion strategies-pulse-coupled neural network based on the structure tensor and maximum based-are applied to combine the three types of layers, based on the layers' various properties. The three different types of fused sublayers are combined to create the fused image at the end. A total of 40 pairs of brain images from four separate categories of medical conditions were tested in experiments. The pair of images includes various case studies including magnetic resonance imaging (MRI) , TITc, single-photon emission computed tomography (SPECT) and positron emission tomography (PET). We included qualitative analysis to demonstrate that the visual contrast between the structure and the surrounding tissue is increased in our proposed method. To further enhance the visual comparison, we asked a group of observers to compare our method's outputs with other methods and score them. Overall, our proposed fusion scheme increased the visual contrast and received positive subjective review. Moreover, objective assessment indicators for each category of medical conditions are also included. Our method achieves a high evaluation outcome on feature mutual information (FMI), the sum of correlation of differences (SCD), Qabf and Qy indexes. This implies that our fusion algorithm has better performance in information preservation and efficient structural and visual transferring.

11.
J Imaging ; 10(1)2024 Jan 20.
Artigo em Inglês | MEDLINE | ID: mdl-38276320

RESUMO

Endoscopies are helpful for examining internal organs, including the gastrointestinal tract. The endoscope device consists of a flexible tube to which a camera and light source are attached. The diagnostic process heavily depends on the quality of the endoscopic images. That is why the visual quality of endoscopic images has a significant effect on patient care, medical decision-making, and the efficiency of endoscopic treatments. In this study, we propose an endoscopic image enhancement technique based on image fusion. Our method aims to improve the visual quality of endoscopic images by first generating multiple sub images from the single input image which are complementary to one another in terms of local and global contrast. Then, each sub layer is subjected to a novel wavelet transform and guided filter-based decomposition technique. To generate the final improved image, appropriate fusion rules are utilized at the end. A set of upper gastrointestinal tract endoscopic images were put to the test in studies to confirm the efficacy of our strategy. Both qualitative and quantitative analyses show that the proposed framework performs better than some of the state-of-the-art algorithms.

12.
J Cancer Res Clin Oncol ; 149(7): 3701-3719, 2023 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-35976445

RESUMO

PURPOSE: Breast cancer, the most prevalent cancer worldwide, consists of 4 main subtypes, namely, Luminal A, Luminal B, HER2-positive, and Triple-negative breast cancer (TNBC). Triple-negative breast tumors, which do not express estrogen, progesterone, and HER2 receptors, account for approximately 15-20% of breast cancer cases. The lack of traditional receptor targets contributes to the heterogenous, aggressive, and refractory nature of these tumors, resulting in limited therapeutic strategies. METHODS: Chemotherapeutics such as taxanes and anthracyclines have been the traditional go to treatment regimens for TNBC patients. Paclitaxel, docetaxel, doxorubicin, and epirubicin have been longstanding, Food and Drug Administration (FDA)-approved therapies against TNBC. Additionally, the FDA approved PARP inhibitors such as olaparib and atezolizumab to be used in combination with chemotherapies, primarily to improve their efficiency and reduce adverse patient outcomes. The immunotherapeutic Keytruda was the latest addition to the FDA-approved list of drugs used to treat TNBC. RESULTS: The following review aims to elucidate current FDA-approved therapeutics and their mechanisms of action, shedding a light on the various strategies currently used to circumvent the treatment-resistant nature of TNBC cases. CONCLUSION: The recent approval and use of therapies such as Trodelvy, olaparib and Keytruda has its roots in the development of an understanding of signaling pathways that drive tumour growth. In the future, the emergence of novel drug delivery methods may help increase the efficiency of these therapies whiel also reducing adverse side effects.


Assuntos
Neoplasias de Mama Triplo Negativas , Estados Unidos , Humanos , Neoplasias de Mama Triplo Negativas/patologia , Epirubicina , Paclitaxel/uso terapêutico , Doxorrubicina/uso terapêutico , Docetaxel
13.
Heliyon ; 9(6): e16421, 2023 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-37251450

RESUMO

SRMS (Src-Related kinase lacking C-terminal regulatory tyrosine and N-terminal Myristoylation Sites) is a non-receptor tyrosine kinase first reported in a 1994 screen for genes regulating murine neural precursor cells. SRMS, pronounced "Shrims", lacks the C-terminal regulatory tyrosine critical for the regulation of the enzymatic activity of Src-family kinases (SFKs). Another remarkable characteristic of SRMS is its localization into distinct SRMS cytoplasmic punctae (SCPs) or GREL (Goel Raghuveera-Erique Lukong) bodies, a pattern not observed in the SFKs. This unique subcellular localization of SRMS could dictate its cellular targets, proteome, and potentially, substrates. However, the function of SRMS is still relatively unknown. Further, how is its activity regulated and by what cellular targets? Studies have emerged highlighting the potential role of SRMS in autophagy and in regulating the activation of BRK/PTK6. Potential novel cellular substrates have also been identified, including DOK1, vimentin, Sam68, FBKP51, and OTUB1. Recent studies have also demonstrated the potential role of the kinase in various cancers, including gastric and colorectal cancers and platinum resistance in ovarian cancer. This review discusses the advancements made in SRMS-related biology to date and the path to understanding the cellular and physiological significance of the kinase.

14.
Cell Signal ; 108: 110723, 2023 08.
Artigo em Inglês | MEDLINE | ID: mdl-37216999

RESUMO

Tamoxifen (Tam) has been the first-line therapy for estrogen receptor-positive breast cancer since its FDA-approval in 1998. Tam-resistance, however, presents a challenge and the mechanisms that drive it have yet to be fully elucidated. The non-receptor tyrosine kinase BRK/PTK6 is a promising candidate as previous research has shown that BRK knockdown resensitizes Tam-resistant breast cancer cells to the drug. However, the specific mechanisms that drive its importance to resistance remain to be investigated. Here, we investigate the role and mechanism of action of BRK in Tam-resistant (TamR), ER+, and T47D breast cancer cells using phosphopeptide enrichment and high throughput phopshoproteomics analysis. We conducted BRK-specific shRNA knockdown in TamR T47D cells and compared phosphopeptides identified in these cells with their Tam-resistant counterpart and parental, Tam-sensitive cells (Par). A total of 6492 STY phosphosites were identified. Of these sites, 3739 high-confidence pST sites and 118 high-confidence pY sites were analyzed for significant changes in phosphorylation levels to identify pathways that were differentially regulated in TamR versus Par and to investigate changes in these pathways when BRK is knocked down in TamR. We observed and validated increased CDK1 phosphorylation at Y15 in TamR cells compared to BRK-depleted TamR cells. Our data suggest that BRK is a potential Y15-directed CDK1 regulatory kinase in Tam-resistant breast cancer.


Assuntos
Neoplasias da Mama , Resistencia a Medicamentos Antineoplásicos , Proteínas Tirosina Quinases , Tamoxifeno , Feminino , Humanos , Neoplasias da Mama/metabolismo , Proteína Quinase CDC2/metabolismo , Linhagem Celular Tumoral , Regulação Neoplásica da Expressão Gênica , Fosforilação , Transdução de Sinais , Tamoxifeno/uso terapêutico , Tirosina/metabolismo , Proteínas Tirosina Quinases/metabolismo
15.
PLoS One ; 18(12): e0294988, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-38128020

RESUMO

The most common cause of breast cancer-related death is tumor recurrence. To develop more effective treatments, the identification of cancer cell specific malignancy indicators is therefore critical. Lipid droplets are known as an emerging hallmark in aggressive breast tumors. A common technique that can be used for observing molecules in cancer microenvironment is fluorescence microscopy. We describe the design, development and applicability of a smart fluorometer to detect lipid droplet accumulation based on the emitted fluorescence signals from highly malignant (MDA-MB-231) and mildly malignant (MCF7) breast cancer cell lines, that are stained with BODIPY dye. This device uses a visible-range light source as an excitation source and a spectral sensor as the detector. A commercial imaging system was used to examine the fluorescent cancer cell lines before being validated in a preclinical setting with the developed prototype. The outcomes indicate that this low-cost fluorometer can effectively detect the alterations levels of lipid droplets and hence distinguish between "moderately malignant" and "highly malignant" cancer cells. In comparison to prior research that used fluorescence spectroscopy techniques to detect cancer biomarkers, this study revealed enhanced capability in classifying mildly and highly malignant cancer cell lines.


Assuntos
Neoplasias da Mama , Humanos , Feminino , Neoplasias da Mama/patologia , Gotículas Lipídicas/metabolismo , Recidiva Local de Neoplasia/patologia , Mama/patologia , Microscopia de Fluorescência , Microambiente Tumoral
16.
Front Oncol ; 12: 856974, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35392236

RESUMO

Breast cancer is the most frequent type of malignancy in women worldwide, and drug resistance to the available systemic therapies remains a major challenge. At the molecular level, breast cancer is heterogeneous, where the cancer-initiating stem-like cells (bCSCs) comprise a small yet distinct population of cells within the tumor microenvironment (TME) that can differentiate into cells of multiple lineages, displaying varying degrees of cellular differentiation, enhanced metastatic potential, invasiveness, and resistance to radio- and chemotherapy. Based on the expression of estrogen and progesterone hormone receptors, expression of human epidermal growth factor receptor 2 (HER2), and/or BRCA mutations, the breast cancer molecular subtypes are identified as TNBC, HER2 enriched, luminal A, and luminal B. Management of breast cancer primarily involves resection of the tumor, followed by radiotherapy, and systemic therapies including endocrine therapies for hormone-responsive breast cancers; HER2-targeted therapy for HER2-enriched breast cancers; chemotherapy and poly (ADP-ribose) polymerase inhibitors for TNBC, and the recent development of immunotherapy. However, the complex crosstalk between the malignant cells and stromal cells in the breast TME, rewiring of the many different signaling networks, and bCSC-mediated processes, all contribute to overall drug resistance in breast cancer. However, strategically targeting bCSCs to reverse chemoresistance and increase drug sensitivity is an underexplored stream in breast cancer research. The recent identification of dysregulated miRNAs/ncRNAs/mRNAs signatures in bCSCs and their crosstalk with many cellular signaling pathways has uncovered promising molecular leads to be used as potential therapeutic targets in drug-resistant situations. Moreover, therapies that can induce alternate forms of regulated cell death including ferroptosis, pyroptosis, and immunotherapy; drugs targeting bCSC metabolism; and nanoparticle therapy are the upcoming approaches to target the bCSCs overcome drug resistance. Thus, individualizing treatment strategies will eliminate the minimal residual disease, resulting in better pathological and complete response in drug-resistant scenarios. This review summarizes basic understanding of breast cancer subtypes, concept of bCSCs, molecular basis of drug resistance, dysregulated miRNAs/ncRNAs patterns in bCSCs, and future perspective of developing anticancer therapeutics to address breast cancer drug resistance.

17.
Front Cell Dev Biol ; 8: 545126, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-33330442

RESUMO

The role of mesenchymal stromal cells (MSCs) in the tumor microenvironment is well described. Available data support that MSCs display anticancer activities, and that their reprogramming by cancer cells in the tumor microenvironment induces their switch toward pro-tumorigenic activities. Here we discuss the recent evidence of pro-tumorigenic effects of stromal cells, in particular (i) MSC support to cancer cells through the metabolic reprogramming necessary to maintain their malignant behavior and stemness, and (ii) MSC role in cancer cell immunosenescence and in the establishment and maintenance of immunosuppression in the tumor microenvironment. We also discuss the mechanisms of tumor microenvironment mediated reprogramming of MSCs, including the effects of hypoxia, tumor stiffness, cancer-promoting cells, and tumor extracellular matrix. Finally, we summarize the emerging strategies for reprogramming tumor MSCs to reactivate anticancer functions of these stromal cells.

18.
Cancer Biol Med ; 17(4): 828-841, 2020 11 15.
Artigo em Inglês | MEDLINE | ID: mdl-33299638

RESUMO

After more than a decade of controversy on the role of stromal cells in the tumor microenvironment, the emerging data shed light on pro-tumorigenic and potential anti-cancer factors, as well as on the roots of the discrepancies. We discuss the pro-tumorigenic effects of stromal cells, considering the effects of tumor drivers like hypoxia and tumor stiffness on these cells, as well as stromal cell-mediated adiposity and immunosuppression in the tumor microenvironment, and cancer initiating cells' cellular senescence and adaptive metabolism. We summarize the emerging data supporting stromal cell therapeutic potential in cancer, discuss the possibility to reprogram stromal cells of the tumor microenvironment for anti-cancer effects, and explore some causes of discrepancies on the roles of stromal cells in cancer in the available literature.


Assuntos
Neoplasias/patologia , Células Estromais , Microambiente Tumoral , Animais , Humanos , Terapia de Imunossupressão , Neoplasias/terapia
19.
Biochim Biophys Acta Mol Basis Dis ; 1866(10): 165880, 2020 10 01.
Artigo em Inglês | MEDLINE | ID: mdl-32592936

RESUMO

Research performed using model organisms such as mice and the fruit fly, Drosophila melanogaster has significantly enhanced our knowledge about cancer biology and the fundamental processes of cancer. This is because the major biological properties and genes associated with cancer including signaling pathways, oncogenes, tumor suppressors, and other regulators of cell growth and proliferation are evolutionary conserved. This review provides bibliometric analysis of research productivity, and performance of authors, institutions, countries, and journals associated with personalized animal cancer models, focussing on the role of Drosophila in cancer research, thus highlighting emerging trends in the field. A total of 1469 and 2672 original articles and reviews for Drosophila cancer model and patient-derived xenograft (PDX) respectively, were retrieved from the Scopus database and the most cited papers were thoroughly analyzed. Our analysis indicates a steadily increasing productivity of the animal models and especially of mouse models in cancer research. In addition to the many different systems that address almost all aspects of tumor research in humanized animal models, a trend towards using tailored screening platforms with Drosophila models in particular will become widespread in the future. Having Drosophila models that recapitulate major genetic aspects of a given tumor will enable the development and validation of novel therapeutic strategies for specific cancers, and provide a platform for screening small molecule inhibitors and other anti-tumor compounds. The combination of Drosophila cancer models and mouse PDX models particularly is highly promising and should be one of the major research strategies the future.


Assuntos
Bibliometria , Modelos Animais de Doenças , Neoplasias/terapia , Oncogenes/genética , Ensaios Antitumorais Modelo de Xenoenxerto , Animais , Animais Geneticamente Modificados , Terapia Combinada/métodos , Drosophila , Humanos , Camundongos , Neoplasias/genética , Neoplasias/patologia
20.
Biomed Opt Express ; 10(2): 399-410, 2019 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-30800488

RESUMO

Instruments that allow the detection of fluorescence signal are invaluable tools for biomedical and clinical researchers. The technique is widely used in cell biology to microscopically detect target proteins of interest in mammalian cells. Importantly, fluorescence microscopy finds major applications in cancer biology where cancer cells are chemically labelled for detection. However, conventional fluorescence detection instruments such as fluorescence imaging microscopes are expensive, not portable and entail potentially high maintenance costs. Here we describe the design, development and applicability of a low-cost and portable fluorometer for the detection of fluorescence signal emitted from a model breast cancer cell line, engineered to stably express the green fluorescent protein (GFP). This device utilizes a flashlight which works in the visible range as an excitation source and a photodiode as the detector. It also utilizes an emission filter to mainly allow the fluorescence signal to reach the detector while eliminating the use of an excitation filter and dichroic mirror, hence, making the device compact, low-cost, portable and lightweight. The custom-built sample chamber is fabricated with a 3D printer to house the detector circuitry. We demonstrate that the developed fluorometer is able to distinguish between the cancer cell expressing GFP and the control cell. The fluorometer we developed exhibits immense potential for future applicability in the selective detection of fluorescently-labelled breast cancer cells.

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