RESUMO

Prostate cancer (PCa) is the second most diagnosed type of cancer in men worldwide. Advanced PCa is resistant to conventional therapies and high recurrence has been associated with high rates of metastasis. Cancer stem cells (CSCs) have been proposed to be responsible for this, due to their ability of self­renewal and differentiation into other cell types. Zinc finger E­box­binding homeobox 1 (ZEB1), a transcription factor involved in the regulation of epithelial­mesenchymal transition (EMT), has been associated with the activation of several mechanisms that lead to resistance to treatment. As recent evidence has shown that CSCs may originate from non­CSCs during EMT, it was hypothesized that knocking down ZEB1 expression in PCa cell lines could revert some properties associated with CSCs. Using lentiviraltransduction, ZEB1 expression was silenced in the PCa DU145 and LNCaP cell lines. The mRNA and protein expression levels of key canonical CSC markers (Krüppel­like factor 4, SOX2, CD44 and CD133) were determined using reverse transcription­-quantitative PCR and western blot analysis, respectively. In addition, the colony forming ability of the ZEB1­knockdown cells was evaluated, and the type of colonies formed (holoclones, paraclones and meroclones) was also characterized. Finally, the ability to form prostatospheres was evaluated in vitro. It was found that in ZEB1­knockdown DU145 cells, the expression levels of CSC phenotype markers (CD44, CD133 and SOX2) were decreased compared with those in the control group. Furthermore, ZEB1­knockdown cells exhibited a lower ability to form prostatospheres and to generate colonies. In conclusion, stable silencing of ZEB1 reversed CSC properties in PCa cell lines. Since ZEB1 is associated with malignancy, therapy resistance and a CSC phenotype in PCa cell lines, targeting ZEB1 may be a key factor to eradicate CSCs and improve the prognosis of patients with advanced PCa.

Assuntos

Autorrenovação Celular/genética , Regulação Neoplásica da Expressão Gênica/genética , Células-Tronco Neoplásicas/patologia , Neoplasias da Próstata/genética , Homeobox 1 de Ligação a E-box em Dedo de Zinco/metabolismo , Antineoplásicos/farmacologia , Antineoplásicos/uso terapêutico , Linhagem Celular Tumoral , Autorrenovação Celular/efeitos dos fármacos , Resistencia a Medicamentos Antineoplásicos/efeitos dos fármacos , Resistencia a Medicamentos Antineoplásicos/genética , Transição Epitelial-Mesenquimal/genética , Regulação Neoplásica da Expressão Gênica/efeitos dos fármacos , Técnicas de Silenciamento de Genes , Humanos , Masculino , Próstata/citologia , Próstata/patologia , Neoplasias da Próstata/patologia , Ensaio Tumoral de Célula-Tronco , Homeobox 1 de Ligação a E-box em Dedo de Zinco/antagonistas & inibidores , Homeobox 1 de Ligação a E-box em Dedo de Zinco/genética

RESUMO

KRAS oncogenic mutations are widespread in lung cancer and, because direct targeting of KRAS has proven to be challenging, KRAS-driven cancers lack effective therapies. One alternative strategy for developing KRAS targeted therapies is to identify downstream targets involved in promoting important malignant features, such as the acquisition of a cancer stem-like and metastatic phenotype. Based on previous studies showing that KRAS activates nuclear factor kappa-B (NF-κB) through inhibitor of nuclear factor kappa-B kinase ß (IKKß) to promote lung tumourigenesis, we hypothesized that inhibition of IKKß would reduce stemness, migration and invasion of KRAS-mutant human lung cancer cells. We show that KRAS-driven lung tumoursphere-derived cells exhibit stemness features and increased IKKß kinase activity. IKKß targeting by different approaches reduces the expression of stemness-associated genes, tumoursphere formation, and self-renewal, and preferentially impairs the proliferation of KRAS-driven lung tumoursphere-derived cells. Moreover, we show that IKKß targeting reduces tumour cell migration and invasion, potentially by regulating both expression and activity of matrix metalloproteinase 2 (MMP2). In conclusion, our results indicate that IKKß is an important mediator of KRAS-induced stemness and invasive features in lung cancer, and, therefore, might constitute a promising strategy to lower recurrence rates, reduce metastatic dissemination, and improve survival of lung cancer patients with KRAS-driven disease.

Assuntos

Adenocarcinoma de Pulmão/enzimologia , Adenocarcinoma de Pulmão/patologia , Movimento Celular , Quinase I-kappa B/metabolismo , Neoplasias Pulmonares/enzimologia , Neoplasias Pulmonares/patologia , Células-Tronco Neoplásicas/patologia , Proteínas Proto-Oncogênicas p21(ras)/metabolismo , Adenocarcinoma de Pulmão/genética , Linhagem Celular Tumoral , Movimento Celular/genética , Proliferação de Células/genética , Autorrenovação Celular/genética , Regulação Neoplásica da Expressão Gênica , Humanos , Neoplasias Pulmonares/genética , Mutação/genética , Invasividade Neoplásica , Células-Tronco Neoplásicas/metabolismo , RNA Interferente Pequeno/metabolismo , Esferoides Celulares/patologia

RESUMO

Blinding corneal scarring is usually treated with allogeneic graft tissue. Nevertheless, the global shortage of donors leaves millions of patients in need of therapy. Traditional tissue engineering strategies involves the combination of cells, growth factors, and scaffolds that can supply cellular biological components allowing to restore the tissue function. The mesenchymal stem cells found in the limbal stroma (L-MSCs) have a self-renewal potential for multilineage differentiation. Thus, in this work we compared the potential of human amniotic membrane (hAM) and porcine small intestine submucosa (SIS) as scaffolds for L-MSCs, aiming at potential applications in corneal regeneration. For that, L-MSCs were seeded on hAM and SIS and we analyzed their viability, actin cytoskeleton, nuclei morphology, cell density, adhesion and surface markers. Our results showed that cells adhered and integrated into both membranes with a high cell density, an important characteristic for cell therapy. However, due to its transparency, the hAM allowed a better observation of L-MSCs. In addition, the analysis of surface markers expression on L-MSCs after two weeks showed a slight increase in the percentages of negative markers for MSCs grown on SIS membrane. Thus, considering a long-term culture, the hAM was considered better in maintaining the MSCs phenotype. Regarding the function as scaffolds, SIS was as efficient as the amniotic membrane, considering that these two types of biological matrices maintained the cell viability, actin cytoskeleton, nuclei morphology and mesenchymal phenotype, without causing cell death. Therefore, our data in vitro provides evidence for future pre-clinical studies were these membranes can be used as a support to transport mesenchymal stem cells to the injured area, creating a kind of temporary curative, allowing the release of bioactive molecules, such as cytokines and growth factors and then promoting the tissue regeneration, both in human and veterinary medicine.

Assuntos

Diferenciação Celular/genética , Transplante de Células-Tronco Mesenquimais , Células-Tronco Mesenquimais/citologia , Âmnio/citologia , Âmnio/crescimento & desenvolvimento , Animais , Proliferação de Células/genética , Autorrenovação Celular/genética , Células Epiteliais/citologia , Humanos , Intestino Delgado/citologia , Intestino Delgado/crescimento & desenvolvimento , Suínos , Engenharia Tecidual/métodos , Alicerces Teciduais

RESUMO

Cancer stem cells (CSCs) are linked to metastasis. Moreover, a discrete group of miRNAs (metastamiRs) has been shown to promote metastasis. Accordingly, we propose that miRNAs that function as metastatic promoters may influence the CSC phenotype. To study this issue, we compared the expression of 353 miRNAs in CSCs enriched from breast cancer cell lines using qRT-PCR analysis. One of the most altered miRNAs was miR-10b, which is a reported promoter of metastasis and migration. Stable overexpression of miR-10b in MCF-7 cells (miR-10b-OE cells) promoted higher self-renewal and expression of stemness and epithelial-mesenchymal transition (EMT) markers. In agreement with these results, inhibiting miR-10b expression using synthetic antisense RNAs resulted in a decrease in CSCs self-renewal. Bioinformatics analyses identified several potential miR-10b mRNA targets, including phosphatase and tensin homolog (PTEN), a key regulator of the PI3K/AKT pathway involved in metastasis, cell survival, and self-renewal. The targeting of PTEN by miR-10b was confirmed using a luciferase reporter, qRT-PCR, and Western blot analyses. Lower PTEN levels were observed in CSCs, and miR-10b depletion not only increased PTEN mRNA and protein expression but also decreased the activity of AKT, a downstream PTEN target kinase. Correspondingly, PTEN knockdown increased stem cell markers, whereas AKT inhibitors compromised the self-renewal ability of CSCs and breast cancer cell lines overexpressing miR-10b. In conclusion, miR-10b regulates the self-renewal of the breast CSC phenotype by inhibiting PTEN and maintaining AKT pathway activation.

Assuntos

Neoplasias da Mama/genética , Neoplasias da Mama/metabolismo , Autorrenovação Celular/genética , MicroRNAs/genética , Células-Tronco Neoplásicas/metabolismo , PTEN Fosfo-Hidrolase/genética , Proteínas Proto-Oncogênicas c-akt/metabolismo , Animais , Linhagem Celular Tumoral , Movimento Celular/genética , Modelos Animais de Doenças , Transição Epitelial-Mesenquimal/genética , Feminino , Perfilação da Expressão Gênica , Regulação Neoplásica da Expressão Gênica , Xenoenxertos , Humanos , Camundongos , PTEN Fosfo-Hidrolase/metabolismo , Fosfatidilinositol 3-Quinases/metabolismo , RNA Mensageiro/genética , Transdução de Sinais , Transcriptoma