Inhibition of proliferation by L-myc antisense DNA for the translational initiation site in human small cell lung cancer.

We evaluated the antiproliferative effect of L-myc antisense DNA in NCI-H209, a human small cell lung cancer (SCLC) cell line overexpressing the L-myc gene. The synthetic DNA used in the present study was oligodeoxynucleoside phosphorothioate, which showed rapid incorporation into NCI-H209 cells and localized mainly in the cell nucleus and weakly in the cytoplasm. The exposure of this cell line to L-myc antisense DNA covering the translational initiation site of L-myc proteins inhibited the cell proliferation in a dose-dependent sequence-specific manner. Furthermore, the growth inhibition by this antisense DNA was correlated with the level of L-myc expression in three SCLC cell lines, NCI-H209, NCI-H510, and NCI-H82. In Western blot analysis, expression of the L-myc proteins was down-regulated in the antisense-treated cells compared with control-treated cells in NCI-H209. Together with unique characteristics of the L-myc gene, including: (a) a frequently amplified and overexpressed state in SCLC; and (b) very restricted and low-level expression in human adult tissues, the present data indicate that L-myc is a good candidate for the target gene for antisense DNA therapy based on molecular biological diagnosis in SCLC.

Altered p16INK4 and retinoblastoma protein status in non-small cell lung cancer: potential synergistic effect with altered p53 protein on proliferative activity.

p16INK4 protein (p16) and retinoblastoma protein (pRB), like p53 protein, are important tumor suppressors that regulate the cell cycle. We immunohistochemically examined fresh-frozen specimens of 114 resected non-small cell lung cancers (NSCLCs) for loss of p16 and pRB expression, together with aberrant accumulation of p53 protein and the proliferative activity determined by the Ki-67 index. Three pRB-positive tumors were uninterpretable for p16 status. Of the remaining 111 tumors, 30 (27%) lacked p16 expression, and 10 (9%) lost pRB expression. No tumors showed coincident loss of both proteins, supporting the hypothesis that they function in a single pathway. Of 25 tumors, including 4 p16-negative tumors, examined by Southern blot analysis, only 2 p16-negative tumors were considered to have reduced gene dosage consistent with possible homozygous deletion of the CDKN2 gene encoding p16, suggesting that immunohistochemistry is a sensitive and suitable method to screen for p16 alteration. Loss of p16 expression did not correlate with any clinical factors or p53 status, whereas loss of pRB expression correlated with heavy smoking (P = 0.03 by Fisher's exact test and P = 0.01 by the multivariate logistic regression analysis). Proliferative activity was considerably higher in p53-positive tumors than in p53-negative tumors (P < 0.001). Loss of p16 or pRB expression was associated with a further increase in proliferative activity in the p53-positive tumors (P = 0.009) but not with proliferative activity in the p53-negative tumors. These results suggest that alteration of the p16/pRB pathway is relatively frequently involved in the development and progression of NSCLCs and that its effect on the proliferative activity is potentially synergistic with altered p53 protein.

Prognostic significance of p27KIP1 protein and ki-67 growth fraction in non-small cell lung cancers.

We immunohistochemically examined specimens of 215 surgically resected non-small cell lung cancers (NSCLCs) for p27KIP1 protein (p27) expression and the growth fraction determined by the Ki-67 labeling index (LI). The NSCLCs analyzed showed considerable heterogeneity in both p27 and Ki-67 LIs; 25 of 207 (13%) lacked p27 expression (p27 LI < 5%), and 116 of 215 (54%) showed a high Ki-67 LI (>30%). The p27 LI was not significantly associated with the Ki-67 LI. A chi2 test showed that loss of p27 expression was inversely correlated with smoking (P = 0.01) and that a high Ki-67 LI was significantly associated with male gender, squamous cell carcinoma histology, and smoking (P < 0.0001 each). Prognostic values of p27 and Ki-67 expression were evaluated in 109 tumors of postsurgical pathological stages I and II. Patients with tumors lacking p27 expression survived for a significantly shorter time than patients with tumors expressing p27 (5-year survival rates, 38% and 68%, respectively; P = 0.02). Patients with tumors having a high Ki-67 LI survived for a significantly shorter time than patients with tumors having a low Ki-67 LI (5-year survival rates, 48% and 78%, respectively; P = 0.005). Multivariate analysis showed that loss of p27 expression tended to be an unfavorable prognostic factor (P = 0.054), whereas a high Ki-67 LI was a significant and independent unfavorable prognostic factor (P = 0.004). When analyzed by cell types, loss of p27 expression was a significant and independent unfavorable prognostic factor in squamous cell carcinomas (P = 0.01), whereas a high Ki-67 LI was a significant and independent unfavorable prognostic factor in nonsquamous cell carcinomas (P = 0.007). We further evaluated the importance of p27 expression in clinical outcome in combination with the Ki-67 LI and ras p21 protein (ras) expression, which we previously reported as an important prognostic factor in NSCLCs. Patients with tumors lacking p27 expression and having a high Ki-67 LI survived for a significantly shorter time than those with tumors expressing p27 and having a high Ki-67 LI (5-year survival rates, 17% and 52%, respectively; P = 0.003). Patients with p27-negative and ras-positive tumors survived for a significantly shorter time than those with both p27- and ras-positive tumors (5-year survival rates, 0% and 38%, respectively; P < 0.0001). These results indicate the pivotal roles of p27 and Ki-67 expression in the clinical outcome of NSCLCs.

Prognostic significance of p53 and ras p21 expression in nonsmall cell lung cancer.

BACKGROUND: Alterations of the p53 gene are one of the most common genetic changes in various types of cancer, including lung cancer. Abnormalities in the ras genes, including point mutations and overexpression, are another common feature in the molecular biology of lung cancer and are associated with a poorer prognosis. The authors' purpose was to determine expression of the mutated p53 gene in nonsmall cell lung cancer (NSCLC) specimens that were studied for expression of ras p21 and to document whether altered p53 expression was also an important factor for survival. METHODS: Ninety-six patients with NSCLC underwent surgical resection between 1977 and 1985, 63 of whom received postoperative combination chemotherapy. None received radiation therapy. Tumor specimens were analyzed for altered p53 expression by immunohistochemistry. Univariate and multivariate analyses were performed to assess the association between p53 expression and survival. RESULTS: Fifty-six (58%) of 96 tumor specimens showed altered p53 expression, and 91 patients were analyzed for survival. Altered p53 expression did not correlate with clinicopathologic characteristics except for postsurgical pathologic tumor (pT) classification. The patients with altered p53 expression survived for a significantly shorter period after surgery than those without p53 expression, including all patients who underwent resection and potentially curative resection (P = 0.02 and P = 0.048, respectively, generalized Wilcoxon test). Multivariate analysis showed independent prognostic significance for altered p53 expression (hazard ratio [HR] = 1.72, P = 0.04) and surgical cure (HR = 4.69, P < 0.001). The combined analysis of mutated p53 and ras p21 expression in the same tumor specimens revealed that patients with p53- and ras p21-negative tumors survived the longest among those with different p53 and ras p21 features (P = 0.005, generalized Wilcoxon test). CONCLUSION: Altered p53 expression is a significant and independent negative prognostic factor for patients with surgically resected NSCLC: Combined immunohistochemical analysis of mutated p53 and ras p21 expression can divide patients with NSCLC into more accurate prognostic groups. If the current findings can be confirmed in larger prospective studies, combined immunohistochemical analysis of mutated p53 and ras p21 expression can be a useful clinical tool for stratifying patients with NSCLC into accurate prognostic groups and for identifying the population with a different risk of recurrence.

Predictive value of expression of p16INK4A, retinoblastoma and p53 proteins for the prognosis of non-small-cell lung cancers.

The predictive value of expression of p16INK4A, retinoblastoma (Rb) and p53 proteins for prognosis was evaluated in 76 patients with non-small-cell lung cancers (NSCLCs) that were potentially curatively resected between 1990 and 1995, using the results of immunostaining analyses of these proteins as reported in our previous study (Kinoshita et al, 1996). Of these NSCLCs, 22 (29%) lacked p16 protein expression and eight (11%) Rb protein, while 30 (39%) showed positive (altered) p53 protein expression. Survival of patients with p16-negative tumours was not significantly different from that of patients with p16-positive tumours (5-year survival rates 67% and 72% respectively, P = 0.8), nor was survival of patients with Rb-negative tumours significantly different from that of patients with Rb-positive tumours (5-year survival rates 42% and 69% respectively, P = 0.9). Moreover, survival of patients with p16/Rb-negative (either p16- or Rb-negative) tumours was not significantly different from that of patients with p16/Rb-positive (both p16- and Rb-positive) tumours (5-year survival rates 67% and 68% respectively, P = 0.7). In contrast, survival of patients with p53-positive (altered) tumours tended to be shorter than that of patients with p53-negative (unaltered) tumours (5-year survival rates 56% and 78% respectively, P = 0.06). In univariate analysis of potential prognostic factors, p16, Rb and p16/Rb proteins were not significant prognostic factors in the present cohort of potentially curatively resected NSCLCs. Altered p53 protein status tended to be a negative prognostic factor (P = 0.06 by the univariate analysis). These results indicate that loss of p16 protein alone, or in combination with loss of Rb protein, does not predict the clinical outcome of patients with resected NSCLCs.

Expression of E1AF/PEA3, an Ets-related transcription factor in human non-small-cell lung cancers: its relevance in cell motility and invasion.

Cell invasion and metastasis characterize the malignant potential of non-small-cell lung cancers (NSCLCs). We have previously reported that E1AF, a member of the Ets-related transcription factor family, confers invasive phenotype on breast cancer and oral squamous-cell carcinoma cell lines. In our study, we analyzed the E1AF expression in cell lines and resected tumors of NSCLCs by Northern blot and in situ hybridization analyses and found that 15 of 17 cell lines and 12 of 19 tumors expressed E1AF mRNA while normal lung tissue and concomitant normal cells within tumors did not. To examine the biologic importance of E1AF in NSCLCs, we introduced the E1AF gene into VMRC-LCD and NCI-H226, NSCLC cell lines lacking E1AF expression, and examined cell motility and invasion activities. E1AF-transfected VMRC-LCD cells showed increased cell motility that was 2-fold that of parental and vector-transfected control cells (p < 0.01), and both cell motility and invasion were increased 1.6-fold in NCI-H226 (p < 0.01). Furthermore, hepatocyte growth factor (HGF), which is one of the most effective cell-scattering factors, stimulated the motile and invasive activities in E1AF-transfected VMRC-LCD and NCI-H226 cells but not in their parental or vector-transfected control cells. Ets-1 mRNA expression was found in E1AF-transfected VMRC-LCD cells but not in parental or vector-transfected cells. HGF further induced expression of the Ets-1 and urokinase-type plasminogen activator (uPA) genes specifically in E1AF-transfected cells. These findings suggest that E1AF plays a substantial role in the cell motility and invasion of NSCLCs.

Differential retinoblastoma and p16(INK4A) protein expression in neuroendocrine tumors of the lung.

BACKGROUND: Neuroendocrine neoplasms of the lung represent a wide spectrum of phenotypically and biologically distinct entities. Their histopathologic diagnosis, which carries therapeutic and prognostic significance, may sometimes be difficult because of their overlapping features. We previously demonstrated that large cell neuroendocrine carcinomas (LCNECs) and small cell lung carcinomas (SCLCs) failed to show positive nuclear staining of RB protein (RB-), whereas typical and atypical carcinoids (TCs and ACs) showed nuclear RB immunostaining (RB+). METHODS: In the current study, a series of 58 surgically resected lung tumors, of which 33 tumors were initially diagnosed as SCLCs and 25 as TCs or ACs, were studied for RB and p16 protein expression by immunohistochemistry. They were also reviewed for their pathologic diagnosis; the reviewers were blinded to the RB and p16 protein status. RESULTS: Nineteen tumors were diagnosed as TCs, 5 as ACs, 7 as LCNECs, and 27 as SCLCs. Three of seven LCNECs were RB+, whereas the other four were RB-. In contrast, all 19 TCs were RB+ and all 27 SCLCs were RB-. In addition, two of five ACs were RB+, whereas the other three were RB-. Interestingly, all 3 RB+ LCNECs and the 1 RB+ AC tested failed to show nuclear staining of p16 protein in any tumor cells (p16-), although some normal stromal cells showed nuclear staining of p16 protein (p16+) as positive internal controls, indicating loss of p16 function in these tumors. It is also noteworthy that the three RB+ LCNECs were initially diagnosed as SCLCs and one of the RB- ACs was initially considered a TC. With the exception of TCs, tumors were significantly more prevalent among heavy smokers with >20 pack-years compared with nonsmokers and light smokers with < or = 20 pack-years (P < 0.01). CONCLUSIONS: These findings suggest that all SCLCs and LCNECs have abnormalities in the p16:RB pathway, as do at least certain ACs, whereas the p16:RB pathway is normal in TCs.