RESUMEN
Breast cancer is the second most cancer worldwide in females. The primary factor responsible for tumor recurrence is the presence of breast cancer stem cells (BCSCs), which escape the chemo-radiotherapy. In this study, we have investigated the role of Secretory phospholipase-A2 Group 2A (sPLA2-IIA) that is overexpressed in BCSCs of MCF7 and MDA-MB-231 breast cancer cell lines. Further, overexpression of sPLA2-IIA revealed an increased EGFR/JNK/c-JUN/c-FOS signaling in BCSCs, while sPLA2-IIA knockdown significantly reduced the percentage of BCSCs and decreased signaling in both the cell lines. Importantly, sPLA2-IIA knockdown showed differentiation of BCSCs. Strikingly, PET imaging showed a decreased metastatic potential of BCSCs. Our study revealed a novel role of sPLA2-IIA in regulating BCSCs, which play a crucial role in regulating the differentiation and metastatic potential of BCSCs.
Asunto(s)
Neoplasias de la Mama , Fosfolipasas A2 Secretoras , Femenino , Humanos , Fosfolipasas A2 Secretoras/genética , Fosfolipasas , Recurrencia Local de Neoplasia , Diferenciación Celular , Células Madre Neoplásicas , Fosfolipasas A2 Grupo II/genéticaRESUMEN
Wnt signaling plays a pivotal role in regulating activation, proliferation, stem cell renewal, and differentiation of hair follicle stem cells (HFSCs). Secreted frizzled-related protein 1 (Sfrp1), a Wnt antagonist is upregulated in the HFSCs; however, its role in the HFSCs regulation is still obscure. Here, we show that Sfrp1 loss showed a depletion of HFSCs, enhanced HFSC proliferation, and faster hair follicle cycle at PD21-PD28; HFSC markers, such as Lgr5 and Axin2, were decreased in both the Sfrp1+/- and Sfrp1-/- HFSCs. In addition, the second hair follicle cycle was also faster compared with WT. Importantly, Sfrp1-/- showed a restoration of HFSC by second telogen (PD49), whereas Sfrp1+/- did not show restoration with still having a decreased HFSC. In fact, restoration of HFSCs was due to a pronounced downregulation of ß-catenin activity mediated through a cross-talk of BMP-AKT-GSK3ß signaling in Sfrp1-/- compared with Sfrp1+/-, where downregulation was less pronounced. In cultured keratinocytes, Sfrp1 loss resulted in enhanced proliferation and clonogenicity, which were reversed by treating with either BMPR1A or GSK3ß inhibitor thereby confirming BMP-AKT-GSK3ß signaling involved in ß-catenin regulation in both the Sfrp1+/- and Sfrp1-/- mice. Our study reveals a novel function of Sfrp1 by unraveling an in vivo molecular mechanism that regulates the HFSCs pool mediated through a hitherto unknown cross-talk of BMP-AKT-GSK3ß signaling that maintains stem cell pool balance, which in turn maintains skin tissue homeostasis.
Asunto(s)
Folículo Piloso , Proteínas de la Membrana/metabolismo , beta Catenina , Animales , Glucógeno Sintasa Quinasa 3 beta/metabolismo , Péptidos y Proteínas de Señalización Intracelular , Proteínas de la Membrana/genética , Ratones , Proteínas Proto-Oncogénicas c-akt/metabolismo , Células Madre/metabolismo , Vía de Señalización Wnt/fisiología , beta Catenina/metabolismoRESUMEN
BACKGROUND: Oral Squamous Cell Carcinoma (OSCC) is a highly prevalent cancer in the Indian subcontinent. The major cause of mortality in OSCC patients is metastasis. Epithelial-to-mesenchymal transition (EMT) marks an important step in the metastatic process. Additionally, TP53, an important tumor suppressor gene, is also a significant determinant of the treatment outcome, and also plays a role in EMT. Therefore, understanding the interconnections between ultrastructural features, EMT status and TP53 mutational status is of vital importance. METHODS AND RESULTS: The ultrastructure of five OSCC cell lines was visualized by transmission electron microscopy. Trans-well invasion and migration assays as well as scratch-wound assay, and the expression of various EMT-related genes were utilized to assess the EMT status of the cell lines. The TP53 exons were amplified for the ACOSC3, ACOSC4 and ACOSC16 cell lines and sequenced and the mutations in the gene were identified by sequence alignment. The TP53 mutation in the UPCI:SCC029B cell line has been previously reported, while UPCI:SCC040 has been reported to harbor a wild type TP53. The ACOSC4 cell line which showed the shortest intercellular gaps, also had the least invasive and migratory potential. Interestingly, ACOSC4 showed the highest expression of E-cadherin and the lowest expression of Vimentin, TWIST1, ZEB1, and MMPs. Additionally, TP53 gene of ACOSC4 was unmutated, whereas the ACOSC3 and ACOSC16 harbored TP53 mutations. The mutation in ACOSC3 (R196*) was also found in 7 TCGA samples. Similarly, the UPCI:SCC040 cell line that harbors a wild type TP53 showed shorter intracellular gaps. CONCLUSIONS: Cellular migratory properties are associated with cellular ultrastructure, epithelial-to-mesenchymal transition status and the status of TP53 mutation in the genome.
Asunto(s)
Carcinoma de Células Escamosas , Neoplasias de Cabeza y Cuello , Neoplasias de la Boca , Humanos , Neoplasias de la Boca/genética , Carcinoma de Células Escamosas/genética , Transición Epitelial-Mesenquimal/genética , Carcinoma de Células Escamosas de Cabeza y Cuello , Línea Celular , Proteína p53 Supresora de Tumor/genéticaRESUMEN
Breast cancer stem cells (BCSCs) are slow cycling cells that escape the traditional chemo-radio-therapy, thereby contributing in resistance and recurrence. Although several markers have been identified, it is still challenging to develop strategies targeting them. In this study, we have isolated BCSCs from MCF-7 cell line using markers CD44+/CD24-/low, which showed higher percentage of mammospheres in CSC population. Moreover, in vivo tumorigenic potential of BCSCs showed as low as 10,000 cells had the ability to develop tumors when transplanted into NOD-SCID mice. We observed an increased level of EMT markers in CSC population. Overexpression of secretory phospholipase sPLA2-IIA was found in CSCs. Further, we have uncovered the upregulation of sPLA2-IIA mediated through JNK signaling in breast cancer cells whereas knockdown of sPLA2-IIA reduces JNK signaling, cell proliferation, EMT and in vivo tumorigenic potential in breast cancer cells. Our study reveals overexpression of sPLA2-IIA in two different breast cancer cells such as MCF7 (ER+,PR+) and a triple negative, MDA-MB-231 (ER-PR-HER2-). Further, the novel role of sPLA2-IIA was discerned by unraveling the molecular mechanism, which regulates the cell proliferation and metastasis in breast cancer cells.
RESUMEN
Secretory phospholipase A2 Group-IIA (sPLA2 -IIA) catalyzes the hydrolysis of the sn-2 position of glycerophospholipids to yield fatty acids and lysophospholipids. sPLA2 -IIA is deregulated in various cancers; however, its role in hair follicle stem cell (HFSC) regulation is obscure. Here we report a transgenic mice overexpressing sPLA2 -IIA (K14-sPLA2 -IIA) showed depletion of HFSC pool. This was accompanied with increased differentiation, loss of ortho-parakeratotic organization and enlargement of sebaceous gland, infundibulum and junctional zone. The colony forming efficiency of keratinocytes was significantly reduced. Microarray profiling of HFSCs revealed enhanced level of epithelial mitogens and transcription factors, c-Jun and FosB that may be involved in proliferation and differentiation. Moreover, K14-sPLA2 -IIA keratinocytes showed enhanced activation of EGFR and JNK1/2 that led to c-Jun activation, which co-related with enhanced differentiation. Further, depletion of stem cells in bulge is associated with high levels of chromatin silencing mark, H3K27me3 and low levels of an activator mark, H3K9ac suggestive of alteration in gene expression contributing toward stem cells differentiation. Our results, first time uncovered that overexpression of sPLA2 -IIA lead to depletion of HFSCs and differentiation associated with altered histone modification. Thus involvement of sPLA2 -IIA in stem cells regulation and disease pathogenesis suggest its prospective clinical implications. Stem Cells 2016;34:2407-2417.
Asunto(s)
Diferenciación Celular , Epidermis/enzimología , Fosfolipasas A2 Grupo II/metabolismo , Folículo Piloso/citología , Proteínas Quinasas JNK Activadas por Mitógenos/metabolismo , Proteínas Proto-Oncogénicas c-jun/metabolismo , Células Madre/citología , Envejecimiento/metabolismo , Animales , Proliferación Celular , Activación Enzimática , Receptores ErbB/metabolismo , Perfilación de la Expresión Génica , Histonas/metabolismo , Homeostasis , Hiperplasia , Queratinocitos/metabolismo , Lisina/metabolismo , Metilación , Ratones Transgénicos , Paraqueratosis/patología , Glándulas Sebáceas/patología , Transducción de Señal , Células Madre/metabolismoRESUMEN
Tissue stem cells have been proposed to segregate the chromosomes asymmetrically (in a non-random manner), thereby retaining preferentially the older "immortal" DNA strands bearing the stemness characteristics into one daughter cell, whereas the newly synthesized strands are segregated to the other daughter cell that will commit to differentiation. Moreover, this non-random segregation would protect the stem cell genome from accumulating multiple mutations during repeated DNA replication. This long-standing hypothesis remains an active subject of study due to conflicting results for some systems and lack of consistency among different tissue stem cell populations. In this review, we will focus on work done in the hair follicle, which is one of the best-understood vertebrate tissue stem cell system to date. In cell culture analysis of paired cultured keratinocytes derived from hair follicle, stem cells suggested a non-random segregation of chromosome with respect to the older DNA strand. In vivo, the hair follicle stem cells appear to self-renew and differentiate at different phases of their homeostatic cycle. The fate decisions occur in quiescence when some stem cells migrate out of their niche and commit to differentiation without self-renewal. The stem cells left behind in the niche self-renew symmetrically and randomly segregate the chromosomes at each division, making more stem cells. This model seems to apply to at least a few other vertebrate tissue stem cells in vivo.
Asunto(s)
Células Madre Adultas/citología , Células Madre Adultas/metabolismo , ADN/metabolismo , Folículo Piloso/citología , Folículo Piloso/metabolismo , Homeostasis , Animales , Cromosomas/metabolismo , Humanos , Especificidad de ÓrganosRESUMEN
Disabled 2 (Dab2), an adaptor protein, is up regulated in the hair follicle stem cells (HFSCs); however, its role in any tissue stem cells has not been studied. In the present study, we have reported that Dab2 conditional knockout (Dab2-cKO) mice exhibited a delay in the HF cycle due to perturbed activation of HFSCs. Further, Dab2-cKO mice showed a reduction in the number of HFSCs and reduced colony forming ability of HFSCs. Dab2-cKO mice showed extended quiescence of HFSCs concomitant with an increased expression of Nfatc1. Dab2-cKO mice showed a decreased expression of anti-aging genes such as Col17a1, decorin, Sirt2 and Sirt7. Dab2-cKO mice did not show full hair coat recovery in aged mice thereby suggesting an accelerated aging process. Overall, we unveil for the first time, the role of Dab2 that regulate activation and self-renewal of HFSCs.
Asunto(s)
Proteínas Adaptadoras Transductoras de Señales , Proteínas Reguladoras de la Apoptosis , Folículo Piloso , Ratones Noqueados , Células Madre , Animales , Folículo Piloso/metabolismo , Folículo Piloso/citología , Proteínas Adaptadoras Transductoras de Señales/metabolismo , Proteínas Adaptadoras Transductoras de Señales/genética , Ratones , Células Madre/metabolismo , Proteínas Reguladoras de la Apoptosis/metabolismo , Proteínas Reguladoras de la Apoptosis/genética , Autorrenovación de las Células/genética , Ratones Endogámicos C57BL , Proliferación CelularRESUMEN
Regulation of stem cell (SC) proliferation is central to tissue homoeostasis, injury repair, and cancer development. Accumulation of replication errors in SCs is limited by either infrequent division and/or by chromosome sorting to retain preferentially the oldest 'immortal' DNA strand. The frequency of SC divisions and the chromosome-sorting phenomenon are difficult to examine accurately with existing methods. To address this question, we developed a strategy to count divisions of hair follicle (HF) SCs over time, and provide the first quantitative proliferation history of a tissue SC during its normal homoeostasis. We uncovered an unexpectedly high cellular turnover in the SC compartment in one round of activation. Our study provides quantitative data in support of the long-standing infrequent SC division model, and shows that HF SCs do not retain the older DNA strands or sort their chromosome. This new ability to count divisions in vivo has relevance for obtaining basic knowledge of tissue kinetics.
Asunto(s)
Proliferación Celular , Segregación Cromosómica , Folículo Piloso/citología , Células Madre/citología , Animales , Bromodesoxiuridina/farmacología , División Celular/efectos de los fármacos , Femenino , Citometría de Flujo , Proteínas Fluorescentes Verdes/genética , Proteínas Fluorescentes Verdes/metabolismo , Folículo Piloso/efectos de los fármacos , Folículo Piloso/metabolismo , Histonas/genética , Histonas/metabolismo , Masculino , Ratones , Microscopía Confocal , Microscopía Fluorescente , Piridinas/farmacología , Proteínas Recombinantes de Fusión/genética , Proteínas Recombinantes de Fusión/metabolismo , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa , Células Madre/efectos de los fármacos , Células Madre/metabolismoRESUMEN
Skin squamous cell carcinoma (skin SCC) is the most frequently occurring cancer. Skin is the first line of defense that provides protection from the external environment. Skin consists of epidermis, dermis, and hypodermis. The epidermis comprises of inter-follicular epidermis, hair follicles, sebaceous glands, and sweat glands. Stem cells within these epidermal compartments play crucial role in epidermal regeneration and repair. Various factors such as higher exposure to ultraviolet light (UV) of sun, genetic predisposition, exposure to carcinogens, etc. that give rise to skin cancer. Within the skin SCC, there exists a pool of cancer stem cells (CSCs) that are highly quiescent with self-renewal capacity. Further, isolation and molecular characterization of CSCs would enable to unravel mechanism involved in tumor progression, metastasis, relapse, and resistance to chemotherapeutic agents. To understand the sequential events of carcinogenesis, the two-stage skin carcinogenesis murine model is proposed, which employs the topical application of a chemical carcinogen, DMBA that causes several activating mutations occurring in the genes responsible for cell proliferation and growth. Further, initiation is followed by tumor promotion, which is induced by repeated application of tumor-promoting agent, TPA, which fixes the activating mutations resulting in the formation of a benign papilloma. Subsequently, papilloma further progresses to highly malignant SCC. Here, using the two-stage skin carcinogenesis murine model, we provide a detailed protocol for the isolation of CSCs from murine skin SCC. FACS sorting of CSCs is followed by assays such as invitro-spheroid assay, in vivo-tumorigenesis-limiting dilution and in vivo-tumorigenesis-serial transplantation assay and expression profiling.
Asunto(s)
Carcinoma de Células Escamosas , Papiloma , Neoplasias Cutáneas , 9,10-Dimetil-1,2-benzantraceno/efectos adversos , Animales , Carcinogénesis , Carcinógenos , Carcinoma de Células Escamosas/inducido químicamente , Carcinoma de Células Escamosas/complicaciones , Carcinoma de Células Escamosas/genética , Modelos Animales de Enfermedad , Humanos , Ratones , Células Madre Neoplásicas/patología , Papiloma/inducido químicamente , Papiloma/patología , Neoplasias Cutáneas/inducido químicamente , Neoplasias Cutáneas/genética , Acetato de Tetradecanoilforbol/efectos adversosRESUMEN
cWnt-signalling plays a crucial role in stem cell maintenance and tissue homeostasis. Secreted frizzled-related proteins(SFRP), Wnt inhibitors consist of the N-terminal cysteine rich domain(CRD) and the C-terminal netrin(NTR) domain. SFRP1 binds to the Wnt ligands and frizzled receptors(FZ) either through its SFRP1CRD or through its SFRP1Netrin domains; however, very little is known on these binding affinities. Here, we attempted to understand the interactions and binding affinities of SFRP1-Wnt5B, SFRP1-FZ(2, 3 & 7) and Wnt5B-FZ(2, 3 & 7) that are mainly expressed in murine hair follicle stem cells. SFRP1CRD, SFRP1Netrin, Wnt5B and FZ(2, 3 & 7) structures were built using homology modelling, followed by their molecular dynamics simulations. SFRP1CRD showed lower fluctuation when in complex with FZ2, FZ3 and FZ7 and Wnt5B as compared to SFRP1Netrin using RMSF and RMSD. However, free energy showed SFRP1Netrin was energetically more stable than SFRP1CRD. SFRP1Netrin formed more number of interactions with FZ as compared to SFRP1CRD. Importantly, SFRP1Netrin favoured binding to the FZ receptors(FZ3 > FZ7 > FZ2) as compared to Wnt5B ligand. Conversely, the SFRP1CRD showed more affinity towards the Wnt5B ligand as compared to FZ receptors. Wnt5B showed the best binding affinity with FZ3 followed by SFRP1CRD and SFRP1Netrin. Therefore, SFRP1Netrin can bind to the FZ3 with higher binding affinity and may inhibit non-canonical Wnt-signalling pathway. Our study provides the comprehensive information on the binding affinities among the Wnt5B, SFRP1CRD/Netrin and FZ(2, 3 & 7). Thus, this information might also help in designing novel strategies to inhibit aberrant Wnt-signalling.Communicated by Ramaswamy H. Sarma.
Asunto(s)
Receptores Frizzled , Proteínas Wnt , Animales , Receptores Frizzled/química , Receptores Frizzled/metabolismo , Ligandos , Proteínas de la Membrana , Ratones , Netrinas , Transducción de Señal , Proteínas Wnt/química , Proteínas Wnt/metabolismoRESUMEN
BACKGROUND: Since there are no pig embryonic stem cells, pig genetic engineering is done in fetal fibroblasts that remain totipotent for only 3 to 5 wk. Nuclear donor cells that remain totipotent for longer periods of time would facilitate complicated genetic engineering in pigs. The goal of this study was to test the feasibility of using fetal liver-derived cells (FLDC) to perform gene targeting, and create a genetic knockout pig. MATERIALS AND METHODS: FLDC were isolated and processed using a human liver stem cell protocol. Single copy α-1,3-galactosyl transferase knockout (GTKO) FLDCs were created using electroporation and neomycin resistant colonies were screened using PCR. Homozygous GTKO cells were created through loss of heterozygosity mutations in single GTKO FLDCs. Double GTKO FLDCs were used in somatic cell nuclear transfer (SCNT) to create GTKO pigs. RESULTS: FLDCs grew for more than 80 population doublings, maintaining normal karyotype. Gene targeting and loss of heterozygosity mutations produced homozygous GTKO FLDCs. FLDCs used in SCNT gave rise to homozygous GTKO pigs. CONCLUSIONS: FDLCs can be used in gene targeting and SCNT to produce genetically modified pigs. The increased life span in culture compared to fetal fibroblasts may facilitate genetic engineering in the pig.
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Animales Modificados Genéticamente/genética , Clonación de Organismos/métodos , Células Madre Embrionarias/citología , Marcación de Gen/métodos , Hígado/citología , Porcinos/genética , Animales , Técnicas de Cultivo de Célula/métodos , Células Madre Embrionarias/fisiología , Estudios de Factibilidad , Femenino , Feto/citología , Fibroblastos/citología , Fibroblastos/fisiología , Técnicas de Inactivación de Genes , Ingeniería Genética/métodos , Homocigoto , Pérdida de Heterocigocidad/genética , Masculino , Técnicas de Transferencia Nuclear , Embarazo , Cola (estructura animal)/citología , Trasplante HeterólogoRESUMEN
Epithelial-to-mesenchymal transition (EMT) is a fundamental cellular phenomenon that plays an intrinsic role in development, tissue repair, and cancer progression. EMT is tightly regulated by transcription factors that alter gene expression to promote epithelial to mesenchymal phenotype. EMT is also regulated by a diverse array of cytokines and growth factors whose activities are deregulated during malignancy. EMT enables tumor cells to exist in various intermediate states along the epithelial-mesenchymal phenotypic axis that transit from cancer stem cells (CSCs) to circulating tumor cells (CTCs). Recent studies have revealed the importance of CSCs in tumor promotion, invasion and metastasis. The relapsed tumors encompass CSCs which are resistant to radiotherapy and chemotherapy. In this review, we have summarized our current understanding of the molecular mechanisms that regulate EMT induced CSC phenotype. We have highlighted studies implicating the function of TGF-�, Wnt, and Notch regulated non-coding RNAs in driving EMT promoting CSC self-renewal. Finally, we discuss how the EMT and CSCs cause drug resistance with the hope to overcome such resistance as a possible approach for cancer treatment.
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Transición Epitelial-Mesenquimal , Neoplasias/terapia , Células Madre Neoplásicas/citología , Humanos , Invasividad Neoplásica , Metástasis de la Neoplasia , Neoplasias/patologíaRESUMEN
An amendment to this paper has been published and can be accessed via a link at the top of the paper.
RESUMEN
Wnt signaling is involved in the regulation of cancer stem cells (CSCs); however, the molecular mechanism involved is still obscure. SFRP1, a Wnt inhibitor, is downregulated in various human cancers; however, its role in tumor initiation and CSC regulation remains unexplored. Here, we used a skin carcinogenesis model, which showed early tumor initiation in Sfrp1-/- (Sfrp1 knockout) mice and increased tumorigenic potential of Sfrp1-/- CSCs. Expression profiling on Sfrp1-/- CSCs showed upregulation of genes involved in epithelial to mesenchymal transition, stemness, proliferation, and metastasis. Further, SOX-2 and SFRP1 expression was validated in human skin cutaneous squamous cell carcinoma, head and neck squamous cell carcinoma, and breast cancer. The data showed downregulation of SFRP1 and upregulation of SOX-2, establishing their inverse correlation. Importantly, we broadly uncover an inverse correlation of SFRP1 and SOX-2 in epithelial cancers that may be used as a potential prognostic marker in the management of cancer.
Asunto(s)
Carcinogénesis/metabolismo , Epitelio/patología , Proteínas de la Membrana/metabolismo , Células Madre Neoplásicas/patología , Neoplasias Cutáneas/patología , Animales , Carcinogénesis/patología , Carcinoma de Células Escamosas/genética , Carcinoma de Células Escamosas/patología , Progresión de la Enfermedad , Transición Epitelial-Mesenquimal/genética , Regulación Neoplásica de la Expresión Génica , Péptidos y Proteínas de Señalización Intercelular/metabolismo , Proteínas de la Membrana/deficiencia , Ratones , Células Madre Neoplásicas/metabolismo , Factores de Transcripción SOXB1/metabolismo , Transducción de Señal , Neoplasias Cutáneas/genética , Neoplasias Cutáneas/metabolismo , Regulación hacia Arriba/genéticaRESUMEN
BACKGROUND: Tissue stem cells (SCs) and cancer cells proliferation is regulated by many common signalling mechanisms. These mechanisms temporally balance proliferation and differentiation events during normal tissue homeostasis and repair. However, the effect of these aberrant signalling mechanisms on the ultimate fate of SCs and cancer cells remains obscure. METHODS: To evaluate the functional effects of Secretory Phospholipase A2-IIA (sPLA2-IIA) induced abnormal signalling on normal SCs and cancer cells, we have used K14-sPLA2-IIA transgenic mice hair follicle stem cells (HFSCs), DMBA/TPA induced mouse skin tumour tissues, human oral squamous cell carcinoma (OSCC) and skin squamous cell carcinoma (SCC) derived cell lines. FINDINGS: Our study demonstrates that sPLA2-IIA induces rapid proliferation of HFSCs, thereby altering the proliferation dynamics leading to a complete loss of the slow cycling H2BGFP positive HFSCs. Interestingly, in vivo reversion study by JNK inhibition exhibited a significant delay in post depilation hair growth, confirming that sPLA2-IIA promotes HFSCs proliferation through JNK/c-Jun signalling. In a different cellular context, we showed increased expression of sPLA2-IIA in human OSCC and mouse skin cancer tissues. Importantly, a xenograft of sPLA2-IIA knockdown cells of OSCC and SCC cell lines showed a concomitant reduction of tumour volume in NOD-SCID mice and decreased JNK/c-Jun signalling. INTERPRETATION: This study unravels how an increased proliferation induced by a common proliferation inducer (sPLA2-IIA) alters the fate of normal SCs and cancer cells distinctively through common JNK/c-Jun signalling. Thus, sPLA2-IIA can be a potential target for various diseases including cancer. FUND: This work was partly supported by the Indian Council of Medical Research (ICMR-3097) and ACTREC (42) grants.
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Carcinoma/genética , Carcinoma/metabolismo , Fosfolipasas A2 Grupo II/genética , Folículo Piloso/citología , Células Madre/metabolismo , Animales , Carcinoma/patología , Línea Celular Tumoral , Técnicas de Silenciamiento del Gen , Fosfolipasas A2 Grupo II/metabolismo , Humanos , Queratinocitos/metabolismo , Sistema de Señalización de MAP Quinasas , Ratones , Ratones TransgénicosRESUMEN
Oral squamous cell carcinoma (OSCC) is a leading cause of mortality in India owing to the high percentage of tobacco chewers, smokers and alcohol consumption. OSCC is highly heterogeneous in nature; therefore poses a challenge in the treatment of the patient. To better understand the heterogeneity of the tumors, an in vitro cell line model is required. However, the efficiency of establishing cell lines from the oral tumors is low. In the present study, three novel cell lines, namely ACOSC3, ACOSC4, and ACOSC16, were isolated and characterized from advancedstage treatmentnaive OSCCs originating from the buccal mucosa. The three cell lines exhibited polygonal morphology, which is typical of epithelial cells. Furthermore, immunofluorescence revealed the expression of keratins 8 and 14, thereby confirming the epithelial origin of the cells. DNA content analysis of the three OSCC cell lines revealed aneuploidy. Furthermore, an in vitro orosphere assay revealed the formation of primary orospheres. Notably, the OSCC cell lines were able to give rise to tumors when administered subcutaneously into nonobese diabetic/severe combined immune deficiency mice. The novelty of the cell lines was also validated by performing short tandem repeat profiling; the STR profiles of the present cell lines did not significantly match with any known established OSCC cell lines present in the DSMZ database, thereby confirming the unique identity of these lines. These cell lines established from tumor samples derived from Indian OSCC patients provide a valuable resource to understand the molecular mechanism involved in tumor resistance and recurrence.
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Carcinoma de Células Escamosas/patología , Línea Celular Tumoral , Neoplasias de la Boca/patología , Adulto , Anciano , Animales , Femenino , Humanos , Masculino , Ratones , Ratones Endogámicos NOD , Ratones SCID , Persona de Mediana Edad , Mucosa Bucal/citología , Mucosa Bucal/patología , Cultivo Primario de Células , Esferoides Celulares , Ensayos Antitumor por Modelo de XenoinjertoRESUMEN
Secretory phospholipase A2 Group-IIA (sPLA2-IIA) is involved in lipid catabolism and growth promoting activity. sPLA2-IIA is deregulated in many pathological conditions including various cancers. Here, we have studied the role of sPLA2-IIA in the development of cyclic alopecia and wound healing response in relation to complete loss of hair follicle stem cells (HFSCs). Our data showed that overexpression of sPLA2-IIA in homozygous mice results in hyperproliferation and terminal epidermal differentiation followed by hair follicle cycle being halted at anagen like stage. In addition, sPLA2-IIA induced hyperproliferation leads to compl pathological conditions including various cancers. Here ete exhaustion of hair follicle stem cell pool at PD28 (Postnatal day). Importantly, sPLA2-IIA overexpression affects the hair shaft differentiation leading to development of cyclic alopecia. Molecular investigation study showed aberrant expression of Sox21, Msx2 and signalling modulators necessary for proper differentiation of inner root sheath (IRS) and hair shaft formation. Further, full-thickness skin wounding on dorsal skin of K14-sPLA2-IIA homozygous mice displayed impaired initial healing response. Our results showed the involvement of sPLA2-IIA in regulation of matrix cells differentiation, hair shaft formation and complete loss of HFSCs mediated impaired wound healing response. These novel functions of sPLA2-IIA may have clinical implications in alopecia, cancer development and ageing.
Asunto(s)
Alopecia/etiología , Alopecia/patología , Fosfolipasas A2 Grupo II/genética , Folículo Piloso/metabolismo , Folículo Piloso/patología , Cabello/patología , Cicatrización de Heridas/genética , Alopecia/metabolismo , Animales , Biomarcadores , Modelos Animales de Enfermedad , Técnica del Anticuerpo Fluorescente , Regulación de la Expresión Génica , Genotipo , Fosfolipasas A2 Grupo II/metabolismo , Ratones , Ratones Transgénicos , Fenotipo , Transducción de SeñalRESUMEN
ABRAXAS is an integral member of BRCA1-complex, which helps in its recruitment to the DNA damage site. It interacts with BRCA1 via its C-terminal phospho-peptide binding motif while the N-terminal associates with RAP80, and thereby recruits the BRCA1-complex at the site of DNA damage. Nonetheless, how ABRAXAS helps in the structural integrity of BRCA1-complex, and its DNA repair mechanism remains elusive. To elucidate the role of ABRAXAS in the DNA repair process, we characterized the ABRAXAS wild type and Arg361Gln mutant using in silico and in vitro approach. It has been observed that ABRAXAS Arg361Gln mutant is responsible for defective nuclear localization of BRCA1-complex, and hence important for DNA repair function. We found conformational changes in ABRAXAS mutant, which impaired binding to RAP80 and further disturb BRCA1-complex localization. The results presented in this paper will help to understand the cause of BRCA1 mislocalization, and various DNA repair defects that occur due to substitution. Comparative study of ABRAXAS wild type and mutant will provide helpful perspective for inhibitor designing that can potentially recompense the deleterious effect(s) of Arg361Gln mutation, and have therapeutic application.
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Proteína BRCA1/metabolismo , Proteínas Portadoras/genética , Proteínas Portadoras/metabolismo , Mutación , Secuencia de Aminoácidos , Sustitución de Aminoácidos , Proteína BRCA1/química , Proteínas Portadoras/química , Codón , Humanos , Modelos Biológicos , Modelos Moleculares , Datos de Secuencia Molecular , Peso Molecular , Unión Proteica , Conformación Proteica , Estabilidad Proteica , Transporte de Proteínas , TermodinámicaRESUMEN
Sophisticated genome manipulation requires the possibility to modify any intergenic or intragenic DNA sequence at will, without leaving large amounts of undesired vector DNA at the site of alteration. To this end, a series of vectors was developed from a previous gene knockout plasmid system to integrate nonselectable foreign DNA at any desired genomic location in yeast, with a minimum amount of residual plasmid DNA. These vectors have two mutated Flp recognition targets (FRT) sequences flanking the KanMX4 gene and multiple sites for subcloning the DNA fragment to be integrated. The selectable marker can be recycled by Flp site-specific excision between the identical FRTs, thereby allowing the integration of further DNA fragments. With this system, the NLS-tetR-GFP and DsRed genes were successfully integrated at the thr1 locus, and the RVB1 gene was tagged at the C-terminus with the V5-epitope-6-histidine tag. This plasmid system provides for a new molecular tool to integrate any DNA fragment at any genome location in [cir+] yeast strains. Moreover, the system can be extrapolated to other eukaryotic cells in which the FLP/FRT system functions efficiently.
Asunto(s)
Clonación Molecular/métodos , Genoma Fúngico , Resistencia a la Kanamicina/genética , Kanamicina/metabolismo , Mutagénesis Sitio-Dirigida , Saccharomyces cerevisiae/genética , Saccharomyces cerevisiae/metabolismo , Ingeniería Genética/métodos , Vectores Genéticos , Recombinación Genética , Reproducibilidad de los Resultados , Sensibilidad y EspecificidadRESUMEN
Receptor Associated Protein 80 (RAP80) is a member of RAP80-BRCA1-CCDC98 complex family and helps in its recruitment to the DNA damage site for effective homologous recombination repair. It encompasses two tandem UIMs (UIM1 and UIM2) motif at its N-terminus, which interact with K-63 linked polyubiquitin chain(s) on H2AX and thereby assemble the RAP80-BRCA1 complex at the damage site. Nevertheless, how RAP80 helps in the structural integrity of BRCA1 complex is still elusive. Considering the role of RAP80 in the recruitment of BRCA1 complex at the DNA damage site, we attempted to explore the molecular mechanism associated with RAP80 and mutation that causes chromosomal aberrations due to its loss of function. There is a significant loss in structural characteristics of RAP80 ΔE81, which impairs its binding affinity with the polyubiquitin chain. This leads to the defective recruitment of RAP80 and BRCA1 complex at the DNA damage site. The results presented here are very useful in understanding the cause of various repair defects (chromosomal aberration) that arise due to this mutation. Comparative study of wild type and ΔE81 could be helpful in designing the small molecules that can potentially compensate the deleterious effect(s) of ΔE81 and hence useful for therapeutic application.