Administration of mesenchymal stem cells (MSCs) improves the recovery from acute kidney injury (AKI).The mechanism may involve paracrine factors promoting proliferation of surviving intrinsic epithelial cells, but these factors remain unknown. In the current study, we found that microvesicles derived from human bone marrow MSCs stimulated proliferation in vitro and conferred resistance of tubular epithelial cells to apoptosis. The biologic action of microvesicles required their CD44-and ␤1-integrin-dependent incorporation into tubular cells. In vivo, microvesicles accelerated the morphologic and functional recovery of glycerol-induced AKI in SCID mice by inducing proliferation of tubular cells. The effect of microvesicles on the recovery of AKI was similar to the effect of human MSCs. RNase abolished the aforementioned effects of microvesicles in vitro and in vivo, suggesting RNA-dependent biologic effects. Microarray analysis and quantitative real time PCR of microvesicle-RNA extracts indicate that microvesicles shuttle a specific subset of cellular mRNA, such as mRNAs associated with the mesenchymal phenotype and with control of transcription, proliferation, and immunoregulation. These results suggest that microvesicles derived from MSCs may activate a proliferative program in surviving tubular cells after injury via a horizontal transfer of mRNA.

This retrospective study further validates ERCC1 and RRM1 genes as reliable candidates for customized chemotherapy and shows a higher impact on the survival of NSCLC patients treated with cisplatin/gemcitabine for ERCC1. Prospective pharmacogenomic studies represent a research priority in early and advanced NSCLC.

BACKGROUND.In patients with cancer, one of the main mechanism of resistance to antimetabolite drugs is related to higher levels of thymidylate synthase (TS) activity.METHODS.To investigate the association between TS expression and histopathologic data, 56 resection specimens from patients with nonsmall cell lung carcinoma (NSCLC) were collected consecutively. TS messenger RNA (mRNA) was evaluated in tumor specimens by using real‐time polymerase chain reaction (PCR) analysis; protein expression was evaluated by using immunohistochemistry (IHC) in formalin‐fixed, paraffin‐embedded (FFPE) specimens; and the analysis of TS transcriptional regulation activity was performed by using real‐time PCR analysis in snap‐frozen normal and tumor specimens.RESULTS.The amplification of the TS gene from FFPE tissues was obtained from all samples, with a median level (unit‐less ratio) of 1.45 (range, 0.34–5.24); whereas positive TS status at IHC (>10% positive cells) was detected in 56% of samples. It is noteworthy that TS expression was significantly higher in squamous cell carcinoma compared with adenocarcinoma when both mRNA levels (2.17 vs. 1.16; P < .0001) and protein levels (P = .0269) were considered in FFPE specimens, and a strong association was observed between mRNA and protein expression (P = .00017). Moreover, higher TS levels were observed in high‐grade tumors (P = .0389 and P = .0068 for mRNA and protein quantification, respectively). The analysis in snap‐frozen samples revealed that the TS gene was up‐regulated strongly in tumors (P = 3.8 × 10−12), and an 8‐fold increase (as a cut‐off value) in the TS mRNA ratio between tumor and corresponding normal tissue was detected in 32 of 56 patients (57%) bearing preferentially squamous cell tumors (P = .0022) and high‐grade tumors (P < .001).CONCLUSIONS.Data from the current study consistently indicated higher TS expression levels in squamous cell and in high‐grade carcinomas. This information may be useful in selecting which patients with NSCLC should receive treatment with TS‐inhibiting agents. Cancer 2006. © 2006 American Cancer Society.

Purpose: The effect of translesion DNA synthesis system in conferring cellular tolerance to DNA-damaging agents has been recently described. DNA polymerase D (Pol D) is part of this machinery and in vitro models showed that it can overcome DNA damages caused by cisplatin and UV rays. The aim of the present study was to investigate the role of Pol D mRNA expression levels in non^small cell lung cancer (NSCLC). Experimental Design: Pol D mRNA expression levels were evaluated by real-time PCR in (a) formalin-fixed paraffin-embedded biopsies of 72 NSCLC patients treated with platinum-based chemotherapy, (b) fresh snap-frozen surgical specimens of tumor and corresponding normal lung tissue from 50 consecutive patients not treated with perioperative or postoperative chemotherapy, and (c) five NSCLC cell lines. Results: High Pol D expression levels were strongly associated with shorter survival at both univariate (6.9 versus 21.1months; P = 0.003) and multivariate (hazard ratio, 3.18; 95% confidence interval, 1.73-5.84; P = 0.008) analysis in the group of platinum-treated patients. By contrast, Pol D expression was not significantly correlated with the prognosis in surgically resected patients (P = 0.54) and mRNA levels did not significantly differ in tumor versus normal lung (P = 0.82). Moreover, endogenous Pol D mRNA expression was found to be inducible by cisplatin in three of five cell lines and significantly associated with in vitro sensitivity (P = 0.01). Conclusions: Taken together, these data indicate Pol D as a predictive rather than prognostic marker worth of further investigation in NSCLC patients candidate to platinum-based chemotherapy.

Background: In real-time RT quantitative PCR (qPCR) the accuracy of normalized data is highly dependent on the reliability of the reference genes (RGs). Failure to use an appropriate control gene for normalization of qPCR data may result in biased gene expression profiles, as well as low precision, so that only gross changes in expression level are declared statistically significant or patterns of expression are erroneously characterized. Therefore, it is essential to determine whether potential RGs are appropriate for specific experimental purposes. Aim of this study was to identify and validate RGs for use in the differentiation of normal and tumor lung expression profiles.