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.

Background: Pivotal studies indicate a role of excision repair cross-complementation 1 (ERCC1) gene and ribonucleotide reductase M1 (RRM1) gene in conferring a differential sensitivity to cytotoxic chemotherapy and epidermal growth factor receptor (EGFR) gene has been recently extensively investigated in non-small-cell lung cancer (NSCLC). Design: Formalin-fixed, paraffin-embedded bronchoscopic/fine needle aspiration biopsies obtained from 70 patients with advanced NSCLC were retrospectively collected to investigate the expression level of ERCC1, RRM1 and EGFR by real-time PCR. Sufficient amounts of messenger RNA (mRNA) were successfully extracted from 61 (87%) specimens, reverse transcribed and amplified with intron-spanning primers. Forty-one patients had stage IV disease and 43 received cisplatin/gemcitabine chemotherapy. Results: A strong correlation between ERCC1 and RRM1 mRNA levels (r_s = 0.624, P < 0.0001) was found. Median survival time in patients with low ERCC1 was significantly longer (17.3 versus 10.9, P = 0.0032 log-rank test) as well as in patients with low RRM1 (13.9 versus 10.9, P = 0.0390 log-rank test). Concomitant low expression levels of ERCC1 and RRM1 (n = 33) were predictive of a better outcome (14.9 versus 10.0, P = 0.0345 log-rank test). Among cisplatin-treated patients, a low ERCC1 level was highly predictive of a longer survival (23.0 versus 12.4, P = 0.0001 log-rank test). No correlation between gene expression levels and histology was reported. No significant correlation between EGFR expression level and survival was found. At multivariate analysis, performance status, response to chemotherapy, presence of weight loss and ERCC1 were independent prognostic factors for survival. Conclusions: 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.

The development of metastases is the main reason for cancer-related death in non–small cell lung cancer (NSCLC). The initiation of metastasis involves an increase in cell motility mediated by the loss of cell-cell adhesion caused by E-cadherin repression, in a process commonly known as epithelial-to-mesenchymal transition. A role for microRNA-200 family members in regulating epithelial-to-mesenchymal transition has recently been indicated but data about their expression in lung tumors is still unavailable. The present study investigated the expression of miR-200c in a panel of NSCLC cell lines (n = 9), and a strong inverse correlation with invasion was detected. Reintroduction of miR-200c into highly invasive/aggressive NSCLC cells induced a loss of the mesenchymal phenotype by restoring E-cadherin and reducing N-cadherin expression, and inhibited in vitro cell invasion as well as in vivo metastasis formation. Moreover, miR-200c overexpression restored the sensitivity of NCI-H1299 cells to cisplatin and cetuximab. Hypermethylation of the promoter region was found to be responsible for the loss of miR-200c in invasive cells, as evaluated by 5-aza-2′-deoxycytidine treatment, methylation-specific PCR, and bisulfite sequencing. In primary tumor specimens obtained from 69 patients with consecutively resected NSCLC, lower miR-200c expression levels were found to be associated with a poor grade of differentiation (P = 0.04), a higher propensity to lymph node metastases (P < 0.01), and with a lower E-cadherin expression (P = 0.01). These data indicate that the loss of miR-200c expression induces an aggressive, invasive, and chemoresistant phenotype, and that assessment of its expression could contribute to a better clinicopathologic definition of patients with NSCLC. Mol Cancer Res; 8(9); 1207–16. ©2010 AACR.

CD95 (Fas/APO-1) and its ligand, CD95L, have long been viewed as a death receptor/death ligand system that mediates apoptosis induction to maintain immune homeostasis. In addition, these molecules are important in the immune elimination of virus-infected cells and cancer cells. CD95L was, therefore, considered to be useful for cancer therapy. However, major side effects have precluded its systemic use. During the last 10 years, it has been recognized that CD95 and CD95L have multiple cancer-relevant nonapoptotic and tumor-promoting activities. CD95 and CD95L were discovered to be critical survival factors for cancer cells, and were found to protect and promote cancer stem cells. We now discuss five different ways in which inhibiting or eliminating CD95L, rather than augmenting, may be beneficial for cancer therapy alone or in combination with standard chemotherapy or immune therapy.

MicroRNAs (miRNAs) are small non‐coding RNAs which regulate gene expression by base‐pairing to the 3′‐UTR of the target mRNA. Recently, miRNAs have been shown to regulate cancer metastasis, however, central molecular mechanisms of this ability still need to be investigated. Epithelial to mesenchymal transition (EMT), which is characterized especially by repression of E‐cadherin expression and increased cell motility, is an essential component of cancer metastasis and progression. In the present study, we found that Snai1, a known transcriptional repressor of E‐cadherin and modulator of EMT, is post‐transcriptionally targeted by miRNA‐30a in non‐small cell lung cancer (NSCLC). Consistent with this, microRNA‐30a expression was found inversely proportional to the invasive potential of various NSCLC cell lines, correlating positively with E‐cadherin (epithelial marker) and negatively with N‐cadherin (mesenchymal marker) expression. Forced re‐introduction of miR‐30a significantly altered cell morphology, in vitro invasion and migration of invasive cell lines, this being paralleled by a downregulation of Snai1 and upregulation of E‐cadherin expression. Using a chicken embryonic metastasis assay, we found that miR‐30a suppresses in vivo distant metastasis to the lungs and liver. Finally, we screened the expression of miR‐30a in 64 consecutively resected NSCLC patients and found that, in 81% of the patients, expression of miR‐30a was downregulated significantly (p < 0.0001) in tumors compared to corresponding normal tissues. These results suggest that miR‐30a targets Snai1, inhibits invasion and metastasis, and is downregulated in NSCLC.

Epithelial-to-mesenchymal transition (EMT) determines the most lethal features of cancer, metastasis formation and chemoresistance, and therefore represents an attractive target in oncology. However, direct targeting of EMT effector molecules is, in most cases, pharmacologically challenging. Since emerging research has highlighted the distinct metabolic circuits involved in EMT, we propose the use of metabolism-specific inhibitors, FDA approved or under clinical trials, as a drug repurposing approach to target EMT in cancer. Metabolism-inhibiting drugs could be coupled with standard chemo- or immunotherapy to combat EMT-driven resistant and aggressive cancers.