Abstracts/Lung Cancer 1.2 (199s) 265-329 273

binding sites for RC-160, a potent growth inhibitory octapeptide analogue of somatostatin. Specific. binding was noted on six of nine SCLC lines. Radio- receptor assay on the cell line NC1 H 69 showed evidence of hvo specific binding sites for RC-160, one with high affinity and the other with low affinity. Binding sites were also found on all five turnour samples. Scatchard analysis indicated the presence of a single class of receptors with high affinity in each case. Histological assessment of the resected specimens before binding assay showed them to be comprised of htmour cells and necrotic tissue, stroma and/or inflammatory cells. Therefore, the spccitic binding of RC-160 may be to tissues other than the tumour cells. In 3 patients, from whom the tumour samples were obtained, radiolabelled somatostatin analoguc scintigraphy using [“‘In] pentetrwtidc was performed prior to su~ery. In all cases, the radiolabel localized the disease. This shrdy demonstrates the presence of specific binding sites for RC-160 in SCLC. Furthermore, the detection of specific binding in vitro and in viva in NSCLC and intrapulmonary carcinoids demonstrates that these tomours contain cells which express specific binding sites for somatostatin. These results suggest that RC- 160 may have 8 ml+ toplay as ‘a therspeutic agent in lung cancer.

The growth of non-smaI1 cell lung carcinoma (NSCLC) c&s was inhibited by retinoic acid after 16 h of treatment. However, the growth of all cell lines except one became refractory to retinoic acid a&r48 h ofexposure. The expression of the hypcrphosphorylatcd retinoblastoma protein species (RB pl IO) was observed to be increased fivefold to tenfold in NSCLC cells within 16 h of exposure to retinoic acid. In the H460a and H226b cell lines ~110 showed some conversion to the undcrphosphorylated ~105 form, after 24 h of retinoic acid treatment. AtIer 48 h ~105 becnmc the predominant form along with a 60K M(r) species. At?er 72 h expression of all RB protein species bccamc almost undetectable in H460a and H226b cells concomitant with increases in cell growth rates. A different pattern of RI3 expression was observed in the H32j and H358 cell lines. In these cells both ~100 and plO5 were induced within 8 h of retinoic acid treatment. Furthermore, the elevated levels and the phosphorylation state of RB in retinoic acid-treated H322j and H358 cells remained essentially unchanged for up to 72 h and only low amounts of the 60K M(r) species were detected. I believe that a post-translational mechanism is responsible for the retinaic acid- mediated induction ofRB since kvcls ofRJ3 mRNA remained relatively unchanged during the time course of retinoic acid exposure. I conclude that retinoic acid inhibited the growth of NSCLC cells by inducing high levels of RB and that increases in RB levels occurred as a result of either an increase in stability of the protein or by downregulation of an RB-specific protease. The inhibition of growth by retinoic acid must involve other molecular events since the H596b cell line which lacks Rl3 protein exhibited growth properties in the presence of retinoic acid similar to those of cells in which RH expression was induced.

Retlaoblastomr protein expressiw in lung cancer: Ao immunobisto- chemical analysis Higashiyama M. Doi 0, Kodama K, Yokouchi H, Tateishi R. Deporbnent o/ Thomcic Surgery, The Center/or Adult Diseases, Nakamichi l-3-3. Higa- shin&h, Osaka 537. Ot~~logy (Switzerland) 1994;51:544-51.

Several analyses of the retinoblastoma (RB) gene in lung cancer at the DNA, mRNA and protein lcvcls have recently been reported. In particular, small cell lung carcinoma shows a high incidence of RB gene abnormalities, suggesting that alterations of this gene may participate in tumor development. In the present study, we used an immunohistoehemical technique with a monoclonal antibody raised against RB protein (PMG3-245) to de&t its expression in representative paraffin sections of tissues obtained from 108 patients with various types of lung cancer treated by surgical resection of the primary tumor. While deletion of RB protein expression was observed in 7 (88%) of 8 small cell lung carcinomas, only 17 (17%) of 100 non-small cell lung carcinomas showed decreased RJ3 protein levels and 6 (6%) showed no RB protein expression. This low incidence of RB protein expression abnormalities III non-small cell lung carcinomas was significant (p < 0.0001). Thus, in contrast to small cell lung carcinoma, abnormalities in RB protein expression may be minor events in non-small cell lung carcinoma, In addition, no significant correlation was found between

abnormabties in RB protein expression and clinical factors such as stage, tllmor size, and nodal involvement in non-small cell lung carcmoma. However, abnormalities in RB protein expression in squamous cell carcinoma were observed only in the less differentiated types (p = 0.144), and there was a weak but not statistically significant association in non-small cell lung carcinoma behveen RJ3 protein status and prognosis (p = 0.09). Therefore, in non-small cell lung carcinoma, although abnormalities in REI protein appear not to be closely associated with tumor development, further studxes on a larger scale and with a longer-term follow-up arc required to dctcrmmc the clinicopathologicsl significance of RB gene abnormalities, in particular the relationship behveen abnormalities of RB protein and differentiation or prognosis.

Co-loc~oftbreeneuropeptidesand NADPHdiihornseioasmall cell lung carcinoma cell line Fabien N, Cespuglio R, Burlet S, Pages MP, Paulin C. Laboratoire de Cy~ologie, Cenbe Hospifolier: Lyun Sud. 69310 Pierre-Benire. Cancer J 1994,7:198-201.

Background - The small cell lung cancer (SCLC) is an cpithclial tumour with the morphological and secretory characteristics of neuroendocrine cells (neuronc-specific enolase, N-CAM, neuropeptides). The establishment of a SCLC cell bne provides ao in vitro model to analyze the neuroendwrine secretion of these malignant cells. Methods Bomb&n, delta sleep inducing factor @SIP) and argininc vasopressin (AVP) were studied by immunohistochcmisby and by in situ hybridization. NADPH diaphorase activity was detected using an hi&chemical technique. Results - All the cells contained bomb&n, DSIP, AVP and displayed a NADPH diaphorax activity which reflects a nitric oxide (NO) synthase activity. Conclusions - These data present the characteristics of a new SCLC cell line (CPN) and show the complexity of its neuroendocrlne secretion; for example, the presence of DSIF’ and NO synthsse activity which have not yet been demonstrated in other SCLC cell lines.

Absence of p16(INK4) p&in is restricted to the subset of lung cancer lines that Mains wildtype RB Ottmon GA, Kmtzkc R4, Coxon A, Kim YW, Kaye FJ. NCI-Navy Onco&~ Branch, Naval Hospital, Bedmda, MD 20889. Oncogenc 199+9:3375-g.

Cell cycle dcpeodmt phosphorylation of the RB tumor suppressor protein is mediated by a family of Gl cyclin dependent kinases (cdks) and cyclins including the activated cdk4:cyclin D complex. The identification of a cdk4 inhibitor. pl6(INK4), as a target for mutations in cultured tumor lines and primaly tumors suggested that RH activity may be affected in these cells. We have examined 88 lung cancer lines for pl6(lNK4) protein cxprcssion and have observed a striking inverse wmlation between the presence of p16@NK4) and wildtype RB. WC demonstrated that only 6155 (11%) of small cell lung cancer (SCLC) samples had absent p16(lNK4) protein, and all 6 belonged to the rare subset of SCLC with wild+ RB expression. Conversely of 48 SCLC samples with absent or mutant RB, all showed detectable levels of p16(INK4) protein. In contrast, we observed that 23133 (70%) of non-SCLC samples had loss of p16(INK4). Twenty-two of 26 non-SCLC lines with wildtype RB had absent p16(lNK4) while 6 of 7 non-SCLC lines with absent or mutant RB had detectable p16(INK4). The inverse correlation of RFI and ~1-4) expression and the absence of pl6(INK4) inactivation in RB (-I-) SCLC lines (0148) confirms a common pl6(INK4)/RB growth suppressor pathway in human cancers and provides evidence that p16(INK4), and not an adjacent gene on chromosome 9p, is a specific target for mutational events.

Abnormal ~53 expression in bumao lung caocer is associated with bistohgic subtypes and patient smokiog history Dosaka-Akita H, Shindoh M, Fujino M, Kinoshita I, Akie K, Katoh M, Kawakami Y. First Deportment of Medicine, Hokkaido Univ. School of Medicine, Norfh IS. West 7. Kilo-ku. Sapporo 060. Am J Clin Pathol 1994;102:6604.

Among the most common mutations in human lung cancer are those atT’ting the ~53 gene. The expression of ~53 in the nucleus is considered an immunobistochemieal reflmtion ofthe nuclear accumulation ofmutant ~53 protein, which is coded by the ~53 gene with misscnsc mutation and has a prolonged half- lift. In the present study, ~53 expression detected by means of immunohistochcmistry occurred frequently in human lung cancer and was associated with histologic subtypes. The alteration in the p53 gene was found