Resistance to TKI treatment is a major obstacle in effective treatment of NSCLC. Besides EGFR mutation status, the mechanisms involved are largely unknown. Some evidence supports a role for microRNA 21 in modulating drug sensitivity of chemotherapy but its role in NSCLC TKI resistance still remains unexplored. This study aimed to investigate whether NSCLC miR-21 mediated resistance to TKIs also results from Pten targeting. Here, we show miR-21 promotes cancer by negatively regulating Pten expression in human NSCLC tissues: high miR-21 expression levels were associated with shorter DFS in 47 NSCLC patients; high miR-21/low Pten expression levels indicated a poor TKI clinical response and shorter overall survival in another 46 NSCLC patients undergoing TKI treatment. In vitro assays showed that miR-21 was up-regulated concomitantly to down-regulation of Pten in pc-9/GR cells in comparison with pc-9 cells. Moreover, over-expression of miR-21 significantly decreased gefitinib sensitivity by down-regulating Pten expression and activating Akt and ERK pathways in pc-9 cells, while miR-21 knockdown dramatically restored gefitinib sensitivity of pc-9/GR cells by up-regulation of Pten expression and inactivation of AKT and ERK pathways, in vivo and in vitro. We propose alteration of miR-21/Pten expression as a novel mechanism for TKI resistance in NSCLC cancer. Our findings provide a new basis for using miR 21/Pten-based therapeutic strategies to reverse gefitinib resistance in NSCLC.

Background/Aims: Klotho is a multifunctional protein expressed predominantly in kidney tubular epithelium. Here, we investigated the protective effects of Klotho on necroptosis in renal ischemic-reperfusion injury (IRI) and the role of oxidative stress in this process. Methods: Mice were subjected to bilateral renal pedicle clamping. Mouse renal tubular epithelial (TCMK-1) cells were exposed to hypoxia/reoxygenation (H/R) or H₂O₂. Kidney samples from acute kidney injury (AKI) patients and controls were examined by immunofluorescence. Klotho protein and N-acetyl-L-cysteine (NAC) were used to define their roles in mediating necroptosis. Necroptosis was assessed by TUNEL staining, immunoblotting, and real-time PCR. Oxidative stress was studied via ELISA, immunoblotting, colorimetric, and thiobarbituric acid reactive substances assays. Results: Renal IRI induced Klotho deficiency in the serum and kidney, but an increase in the urine. The levels of the necroptotic markers receptor-interacting protein kinase (RIP) 1, RIP3, IL-1β, and TUNEL-positive cells increased after IRI; all increases were ameliorated by Klotho. In TCMK-1 cells, Klotho and NAC attenuated the elevation in RIP1, RIP3, and LDH release induced by H/R or H₂O₂. Moreover, Klotho decreased the levels of oxidative stress biomarkers and elevated superoxide dismutase 2 expression in both in vivo and in vitro experiments. Studies in human samples further confirmed the Klotho deficiency and increased formation of RIP3 puncta in AKI kidneys. Conclusion: Klotho protects tubular epithelial cells from IRI and its anti-necroptotic role may be associated with oxidative stress inhibition.

Root is important in acquiring nutrients from soils. Developing marker-assisted selection for wheat root traits can help wheat breeders to select roots desirable for efficient acquisition of nutrients. A recombinant inbred line (RIL) population derived from wheat varieties Xiaoyan 54 and Jing 411 was used to detect QTLs for maximum root length and root dry weight (RDW) under control, low nitrogen and low phosphorus conditions in hydrophobic culture (HC). We totally detected 17 QTLs for the investigated root traits located at 13 loci on 11 chromosomes. These loci differentially expressed under different nutrient supplying levels. The RILs simultaneously harboring positive alleles or negative alleles of the most significant three QTLs for RDW, qRDW.CK-2A, qRDW.CK-2D, and qRDW.CK-3B, were selected for soil column culture (SC) trial to verify the effects of these QTLs under soil conditions. The RILs pyramiding the positive alleles not only had significantly higher shoot dry weight, RDW, nitrogen and phosphorus uptake in all the three treatments of the HC trial, but also had significantly higher RDW distribution in both the top- and sub-soils in the SC trial than those pyramiding the negative alleles. These results suggested that QTL analysis based on hydroponic culture can provide useful information for molecular design of wheat with large and deep root system.

BackgroundLung cancer in nonsmokers tends to be driven by a single somatic mutation or a gene fusion. KIF5B-RET fusion is an oncogene identified in non-small cell lung cancers. In this study, we verified the oncogenic activity of KIF5B-RET fusion and investigated how KIF5B-RET activates the specific signaling pathways for cellular transformation. We aimed to provide a basis for the further development of the therapy for KIF5B-RET positive lung cancer patients.MethodsRT-PCR was used to screen for KIF5B-RET fusions in Chinese lung cancer patients. To verify the oncogenic activity of KIF5B-RET kinase in lung cancer cells, we manipulated its expression genetically followed by colony formation and tumor formation assays. The mechanism by which KIF5B-RET kinase induces proliferation was investigated by western blot, coimmunoprecipitation, and administration of RET, MAPK and STAT3 inhibitors.ResultsOur study identified a KIF5B-RET fusion in Chinese NSCLC patients and demonstrated that KIF5B-RET transfected cells showed a significantly increased proliferation rate and colony-forming ability. Furthermore, we found that KIF5B-RET fusion kinase induced multilevel activation of STAT3 at both Tyr705 and Ser727, and KIF5B-RET-STAT3 signaling related inhibitors repressed the proliferation and tumorigenicity of lung cancer cells significantly.ConclusionsOur data suggest that KIF5B-RET promotes the cell growth and tumorigenicity of non-small cell lung cancers through multilevel activation of STAT3 signaling, providing possible strategies for the treatment of KIF5B-RET positive lung cancers.