Paolo Ceppi

Squamous cell carcinoma of the lung compared with other histotypes shows higher messenger RNA and protein levels for thymidylate synthase

In patients with cancer, one of the main mechanism of resistance to antimetabolite drugs is related to higher levels of thymidylate synthase (TS) activity.

Loss of miR-200c Expression Induces an Aggressive, Invasive, and Chemoresistant Phenotype in Non–Small Cell Lung Cancer

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.

MicroRNA-30a inhibits epithelial-to-mesenchymal transition by targeting Snai1 and is downregulated in non-small cell lung cancer.

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.

Regulation of Axl receptor tyrosine kinase expression by miR-34a and miR-199a/b in solid cancer

Axl is a receptor that induces proliferation, migration and invasion in cancer. In this study, we show that specific microRNAs (miRNAs) target the 3′-UTR of Axl. Luciferase-reporter assays with wild-type and deleted miR-34 and miR-199a/b seed sequences of Axl 3′-UTR confirmed the specificity of targeting. An inverse correlation between Axl protein and miR-34a expression in a panel of non-small cell lung cancer (NSCLC), colorectal cancer (CRC) and breast cancer (BRC) cell lines was observed, while miR-199a/b expression was completely suppressed. Pre-miR transfection inhibited in vitro migration and invasion and, in vivo, reduced the number of distant lung- or liver-metastases in a chorion-allantoic-membrane (CAM) assay. Moreover, methylation-specific PCR on bisulfite-converted DNA obtained from the cell lines showed that the miR-34a promoter methylation status was inversely correlated with its expression, and that miR-199a/b promoter regions were methylated in all cells tested. In a panel of NSCLC tissues (n=44), miR-34a and miR-199a/b were found to be downregulated and significantly co-expressed. A lower expression of all three miRs was significantly associated with squamous histotypes, and, in a preliminary series, NSCLC patients with miR-34a upregulation showed a positive association towards a longer survival. These results indicate that Axl receptor expression can be regulated by miR-34a and miR-199a/b, which are suppressed by promoter methylation in solid cancer cells.

Thymidylate Synthase But Not Excision Repair Cross-Complementation Group 1 Tumor Expression Predicts Outcome in Patients With Malignant Pleural Mesothelioma Treated With Pemetrexed-Based Chemotherapy

PURPOSE The relationship between thymidylate synthase (TS) expression and outcome in patients with malignant pleural mesothelioma (MPM) treated with pemetrexed (P) was retrospectively evaluated. PATIENTS AND METHODS Sixty histologically confirmed patients with MPM previously treated with P and platinum (45 of 60) or as single agent (15 of 60) were retrospectively considered. Eighty-one control patients with MPM not P-treated were also evaluated. TS and excision repair cross-complementation group 1 (ERCC1) gene expression levels were evaluated by real-time polymerase chain reaction and by immunohistochemistry using the H-score. RESULTS Median TS H-score value was 90 (range, 5 to 240). A significant correlation between low TS protein expression and longer time to progression (TTP; 17.9 v 7.9 months; hazard ratio [HR], 2.05, 95% CI, 1.19 to 3.77; P = .02) or overall survival (OS; 30 v 16.7 months; HR, 2.38; 95% CI, 1.15 to 4.91; P = .019) was found when patients were divided according to median H-score. Conversely, TS mRNA levels were not significantly correlated with outcome. In platinum-treated patients (n = 45), no correlation was found with survival according to ERCC1 median H-score, but patients in the lower tertile had a significantly shorter survival (HR, 3.06; 95% CI, 1.08 to 8.69; P = .035). In control MPMs, TS had no prognostic role. At multivariate analysis, TS protein levels were the only independent prognostic factor for both TTP (HR, 2.71; 95% CI, 1.13 to 6.49; P = .02) and OS (HR, 6.91; 95% CI, 1.90 to 25.07; P = .003). CONCLUSION In patients with MPM treated with P-based chemotherapy, low TS protein levels are predictive of improved TTP and OS. The role of TS assessment is worth of prospective validation in future studies on MPM.

Desmocollin-3: a new marker of squamous differentiation in undifferentiated large-cell carcinoma of the lung

Lung cancer classification in small-cell and non-small-cell types was recently challenged by data on the differential efficacy of new cytotoxic agents in specific histotypes. An accurate histotype definition has therefore gained interest in both preoperative and surgical materials, but is a hard task especially in undifferentiated large-cell tumors lacking morphological signs of squamous or glandular differentiation. The responsiveness of these latter subtypes to new drugs apparently more selective for adenocarcinomas or squamous carcinomas is not fully understood, also due to the heterogeneity of diagnostic criteria for this tumor entity. Current immunohistochemical markers are not fully specific and new molecules are to be explored. On the basis of gene expression profiling data, reporting a remarkable differential expression of desmocollin-3 (a protein localized in desmosomal junctions of stratified epithelial) between adeno- and squamous cancers, we immunostained 62 cases of resected undifferentiated large-cell lung carcinomas for desmocollin-3 (and for TTF-1, p63 and mucin stain), to test its ability to identify a (residual) squamous phenotype, if present. Desmocollin-3 was expressed in almost half of the undifferentiated large-cell cancers and was mutually exclusive with TTF-1 (positive in 39%; the remaining 18 % of cases was double negative). Special large-cell carcinoma variants expressed desmocollin-3 in 6 of 6 basaloid, 7 of 12 clear-cell types, again mutually exclusive with TTF-1 expression. None of seven sarcomatoid carcinomas reacted for either marker. In 31 cytological samples diagnosed as ‘non-small-cell lung carcinoma’, desmocollin-3 was again mutually exclusive with TTF-1 and stained all squamous carcinomas, 1 of 19 adenocarcinoma only, and 50% of large-cell carcinoma (all histologically confirmed). This combined morphophenotypic approach may represent a valid adjunct (for both surgical and cytological samples) in the selection of patients with lung cancer to medical treatments tailored according to different efficacy in different lung carcinomas of the squamous, adeno- and large-cell types.

Thymidylate Synthase Expression in Gastroenteropancreatic and Pulmonary Neuroendocrine Tumors

Purpose: The predictive role of the quantification of thymidylate synthase (TS) in tumors treated with antifolate drugs, such as 5-fluorouracil (5-FU), has been extensively reported in a variety of human tumors. Neuroendocrine tumors (NET) represent potential targets of antifolate agents, but no data on TS expression level in these tumors are currently available. Experimental Design: A series of 116 NETs were collected, including 58 gastroenteropancreatic (GEP) and 58 lung NETs. In 24 well-differentiated GEP neuroendocrine carcinomas (WD-NEC), a 5-FU–based treatment was given. Total RNA was extracted from microdissected paraffin blocks. TS mRNA quantification was done by real-time PCR, whereas protein expression was evaluated by immunohistochemistry. Results: By means of both quantification by real-time PCR and immunohistochemistry, a higher TS expression in pulmonary small cell lung cancer and large cell NEC compared with typical and atypical carcinoids was observed (P < 0.01). Similarly, in GEP tumors, a higher TS expression in poorly differentiated carcinomas than both WD-NEC and benign tumors (P < 0.01) was found. In patients with WD-NEC treated with 5-FU, high TS mRNA levels were associated with shorter time to progression (P = 0.002) and overall survival (P = 0.04). This negative prognostic role was confirmed in multivariate analysis adjusting for major prognostic variables (P = 0.01). No association between TS mRNA and survival was observed in WD-NEC patients not receiving 5-FU. Conclusions: This study, for the first time, (a) reports the differential TS expression in the spectrum of NETs and (b) indicates TS as a possible predictive marker of treatment efficacy in WD-NEC patients treated with 5-FU.

Polymerase eta mRNA expression predicts survival of non-small cell lung cancer patients treated with platinum-based chemotherapy.

Purpose: The effect of translesion DNA synthesis system in conferring cellular tolerance to DNA-damaging agents has been recently described. DNA polymerase η (Pol η) 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 η mRNA expression levels in non–small cell lung cancer (NSCLC). Experimental Design: Pol η 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 η expression levels were strongly associated with shorter survival at both univariate (6.9 versus 21.1 months; 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 η 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 η 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 η as a predictive rather than prognostic marker worth of further investigation in NSCLC patients candidate to platinum-based chemotherapy.

Differential Thymidylate Synthase Expression in Different Variants of Large-Cell Carcinoma of the Lung

Purpose: In non–small cell lung cancer, higher thymidylate synthase (TS) levels have been reported in squamous cell carcinoma (SCC) compared with adenocarcinoma (ADC). Data on TS expression in large-cell carcinoma (LCC) are scanty. Experimental Design: TS mRNA and protein levels were analyzed in 42 surgical cases of pulmonary LCC, including 8 large-cell neuroendocrine carcinomas, and were compared with controls represented by ADC (n = 41), SCC (n = 30), and small-cell lung carcinoma (SCLC; n = 33). TS levels were also correlated with the expression of Ki67 and E2F1. Moreover, the reliability of TS expression analysis was assessed in 22 matched cytologic and surgical specimens of non–small cell lung cancer. Results: TS mRNA levels of LCC were comparable with those of control SCC, but significantly higher than those of ADC (P < 0.001) and lower than SCLC (P < 0.001). A correlation between TS mRNA and protein levels was observed in control ADC and SCC, but not in LCC. Large-cell neuroendocrine carcinomas had the highest TS expression, whereas in non-neuroendocrine LCCs, TS protein levels were significantly higher (P = 0.02) in LCC immunoreactive for p63 and desmocollin3 (markers of squamous differentiation) than those expressing TTF-1 (a marker of ADC). Both E2F1 and Ki67 levels were not correlated with TS in LCCs. Finally, a linear correlation in TS protein levels was observed between matched cytologic and surgical specimens. Conclusion: The pulmonary LCC immunoprofile may resemble that of SCCs or ADCs. This immunoprofile is associated with differential TS expression levels, which may support a more appropriate therapeutic strategy decision. (Clin Cancer Res 2009;15(24):7547–52)

Effects of Src kinase inhibition induced by dasatinib in non–small cell lung cancer cell lines treated with cisplatin

c-Src is a tyrosine kinase involved in tumor proliferation, migration, and angiogenesis and has been shown to modulate the cytotoxicity following cisplatin-induced DNA damages. c-Src is frequently activated in non–small cell lung cancer (NSCLC) tissues and cell lines, but no preclinical data regarding the effects of the novel potent Src inhibitor, dasatinib (BMS-354825), in the modulation of cisplatin resistance are currently available. The present study reports that treatment with dasatinib completely abrogated Src phosphorylation in the majority of the NSCLC cell lines tested (n = 7), with modest effects on cell proliferation and survival. In five cell lines, a higher cytotoxicity was observed delivering cisplatin in combination with dasatinib: the most evident effects were found in the squamous H520 cells due to the effective block of cisplatin-induced Src phosphorylation. Moreover, dasatinib treatment significantly blocked cisplatin-induced transcription of a panel of DNA repair and synthesis genes. In addition, a real-time PCR analysis done on tumor and matched normal lung specimens from 44 surgically resected NSCLC patients showed that Src transcripts are significantly upregulated in 23% of cases. In conclusion, Src-directed therapeutic strategies could interfere with cisplatin resistance, possibly allowing to reduce cisplatin doses, thus improving its efficacy. The data of this study support further clinical studies aimed to evaluate the efficacy of Src-inhibiting agents in combination with cisplatin in the treatment of NSCLC. [Mol Cancer Ther 2009;8(11):3066–74]