Involvement of miR-30c in resistance to doxorubicin by regulating YWHAZ in breast cancer cells

MicroRNAs (miRNAs) are small RNA molecules that modulate gene expression implicated in cancer, which play crucial roles in diverse biological processes, such as development, differentiation, apoptosis, and proliferation. The aim of this study was to investigate whether miR-30c mediated the resistance of breast cancer cells to the chemotherapeutic agent doxorubicin (ADR) by targeting tyrosine 3-monooxygenase/tryptophan 5-monooxygenase activation protein zeta (YWHAZ). miR-30c was downregulated in the doxorubicin-resistant human breast cancer cell lines MCF-7/ADR and MDA-MB-231/ADR compared with their parental MCF-7 and MDA-MB-231 cell lines, respectively. Furthermore, we observed that transfection of an miR-30c mimic significantly suppressed the ability of MCF-7/ADR to resist doxorubicin. Moreover, the anti-apoptotic gene YWHAZ was confirmed as a target of miR-30c by luciferase reporter assay, and further studies indicated that the mechanism for miR-30c on the sensitivity of breast cancer cells involved YWHAZ and its downstream p38 mitogen-activated protein kinase (p38MAPK) pathway. Together, our findings provided evidence that miR-30c was one of the important miRNAs in doxorubicin resistance by regulating YWHAZ in the breast cancer cell line MCF-7/ADR.

Autophagy facilitates the sorafenib resistance of hepatocellular carcinoma cells / La autofagia facilita la resistencia al sorafenib de las células del carcinoma hepatocelular

Liver cancer is the second most frequent cause of cancer death in men and the sixth leading cause of cancer death in women. Hepatocellular carcinoma (HCC) represents the major subtype in liver cancer and its five-year survival rate remains very poor. Sorafenib, a molecular targeted therapeutic agent, was the first drug approved for the treatment of patients with HCC. However, the clinical response of sorafenib was seriously limited by drug resistance. Autophagy is an evolutionarily conserved mechanism among all eukaryotes. Recently, many studies have indicated that autophagy can be activated as a cellular protective mechanism in many tumour cells. Thus, we hypothesized that autophagy may play an important role in resistance to sorafenib in hepatocellular carcinoma. Although the exact role of autophagy in the sorafenib resistance of HCC is still complex and further studies are needed to be proven, at least it suggests that autophagy may be a new therapeutic target for the sorafenib resistance of HCC.

El cáncer de hígado es la segunda causa de muerte más frecuente por cáncer en los hombres y la sexta causa de muerte por cáncer en las mujeres. El carcinoma hepatocelular (CHC) representa el subtipo principal en el cáncer de hígado, y su tasa de supervivencia de cinco años sigue siendo muy pobre. El sorafenib, un agente terapéutico dirigido selectivamente a moléculas especificas, fue el primer medicamento aprobado para el tratamiento de pacientes con CHC. Sin embargo, la respuesta clínica de sorafenib estaba seriamente limitada por la resistencia al medicamento. La autofagia es un mecanismo evolutivamente conservado entre todos las eucariotas. Recientemente, muchos estudios han indicado que la autofagia puede activarse como mecanismo de protección celular en muchas células tumorales. Por consiguiente, postulamos la hipótesis de que la autofagia puede desempeñar un papel importante en la resistencia del carcinoma hepatocelular al sorafenib. Aunque el papel exacto de la autofagia en la resistencia al sorafenib del CHC es aún complejo y se necesitan estudios adicionales para ser probado, al menos se sugiere que la autofagia puede ser una nueva meta terapéutica frente a la resistencia del sorafenib en el CHC.

Class 1 integrons contributes to antibiotic resistance among clinical isolates of Escherichia coli producing extended-spectrum beta-lactamases.

Objectives: The objective of this study is to determine the prevalence of antibiotic resistance factors, including the production of extended-spectrum beta-lactamases (ESBLs) and the presence of class 1 integrons among Escherichia coli isolated from clinical specimens. Materials and Methods: Bacterial species identifi cation was performed using a VITEK-2 system (VITEK2 GN-card; bioMérieux, France). Antimicrobial susceptibility testing was determined using the disk diffusion method according to the 2010 Clinical and Laboratory Standards Institute guidelines. Polymerase chain reaction (PCR) was used to detect integrons and amplify variable regions of the blaTEM, blaSHV and blaCTX-M genes. Gene cassettes were detected by deoxyribonucleic acid sequencing. Results: In this study, 58% (100/172) of clinical E. coli isolates were identifi ed as ESBL producers. We found that 90% of the ESBL-producing E. coli isolates harbored the blaCTX-M gene, whereas only 59% and 32% possessed the blaTEM and blaSHV genes respectively. The presence of class 1 integrons was based on the detection of the integrase gene by PCR. A total of 69% of the ESBL-producing isolates were integron-positive. Resistance to 10 antibiotics, including quinolones, sulfonamides and -lactam/enzyme inhibitors, was signifi cantly higher in the class 1 integron-positive isolates (P < 0.05). The occurrence of class 1 integrons in blaTEM, blaSHV and blaCTX-M gene carriers was 72.9%, 84.4% and 68.9%, respectively. Class 1 integrons were detected in 61.5% of the isolates with only one ESBL genotype, but in 69.0% and 92.3% of the isolates with two or three different ESBL genotypes, respectively. Conclusions: Our fi ndings indicate that clinical strains of bacteria with multiple ESBL genotypes may have greater opportunities to carry class 1 integrons.

Beneficial effect of recombinant human growth hormone on the intestinal mucosa barrier of septic rats

The objective of the present study was to investigate the effects of recombinant human growth hormone (rhGH) on the intestinal mucosa barrier of septic rats and explore its possible mechanism. Female Sprague-Dawley rats were randomized into three groups: control, Escherichia coli-induced sepsis (S) and treatment (T) groups. Groups S and T were subdivided into subgroups 1d and 3d, respectively. Expression of liver insulin-like growth factor-1 (IGF-1) mRNA, Bcl-2 and Bax protein levels and the intestinal Bax/Bcl-2 ratio, and plasma GH and IGF-1 levels were determined. Histological examination of the intestine was performed and bacterial translocation was determined. rhGH significantly attenuated intestinal mucosal injuries and bacterial translocation in septic rats, markedly decreased Bax protein levels, inhibited the decrease of Bcl-2 protein expression and maintained the Bax/Bcl-2 ratio in the intestine. rhGH given after sepsis significantly improved levels of plasma GH (T1d: 1.28 ± 0.24; T3d: 2.14 ± 0.48 æg/L vs S1d: 0.74 ± 0.12; S3d: 0.60 ± 0.18 æg/L; P < 0.05) and IGF-1 (T1d: 168.94 ± 65.67; T3d: 201.56 ± 64.98 æg/L vs S1d: 116.72 ± 13.96; S3d: 107.50 ± 23.53 æg/L; P < 0.05) and expression of liver IGF-1 mRNA (T1d: 0.98 ± 0.20; T3d: 1.76 ± 0.17 vs S1d: 0.38 ± 0.09; S3d: 0.46 ± 0.10; P < 0.05). These findings indicate that treatment with rhGH had beneficial effects on the maintenance of the integrity of the intestinal mucosa barrier in septic rats.