Abstracts / Lung Cant ‘er 15 (1996) 381-399

TTF-1 gene expression in human lung tumours Fabbro D. Di Loreto C, Stamerra 0, Beltrami CA, Lonigro R, Damante G. Dpt. Scienze/Xecnologie Biomediche, Universita di Udine, Udine. Em J Cancer Part A Gen Top 1996;32:512-7.

Tissue-specific transcription factors control cell determination and differentiation. ‘FIT-1 is a tissue-specific transcription factor expressed in the thyroid and lung. We investigated the expression of TTF-I in normal human lung, and in various histopathological types of lung cancers by immunohistochemistty. In normal lung, TIT-1 expression was restricted to bronchial andalveolarepitheliaI cells. ‘I-IF-1 expression was found in 7 of the 29 cases of non-small ccl1 lung carcinomas. In these tumours, the expression of TTF-I did not correlate with the histological degree of differentiation, Results obtained using RNam protection assay confirmed that TIT-1 was expressed only in a subset of non-small cell carcinomas. TIT-I, as expected, was not expressed in neoplasms having a neuroendocrine cell origin, such as carcinoids. Interestingly. TTF- I was always expressed in small cell lung carcinomas. These Endings indicate that: (i) small cell lung carcinomas could originate from the endothermal cell lineage and (ii) dedifferentiation processes that operate in these neoplasms do not affect molecular mechanisms necessary for TIT-1 gene expression.

Abnormal expression of p53 detectable by immunostaining techniques was seen in 23 specimens tested. There was no statistically significant correlation between the detection of ~53 aberrations and age, sex, smoking history, histologic type, and tumor stage. Aberrant ~53 protein levels detectable by immunostaining were significantly associated with the clinical and nodal staging of the tumors.

Expression of Ca~+/caImodulin-dependent protein kinase types II and IV, and reduced DNA synthesis due to the Cal+/ calmodulirrdependent protein kinase inhibitor KN-62 (1-[N,O- bis(5-isoquinotinesuIfonyl)-N-methyCL-tyra xine) in small cell lung carcinoma Williams CL, Phelps SH, Porter RA. Molecular Pharmacology Laboratoty, Guthrie Research Institute, One Guthrie Square. Says? PA 18840. Biochem Pharmacol 1996;s 1:707-15.

Because changes in intracellular Ca2+ atTect progression through the mitotic cell cycle, we investigated the role of Ca”-binding proteins in regulating cell cycle progression. Evidence was found demonstrating that the inactivation of Ca*+/calmoduhndependent protein kinase (CaM kinase) inhibits cell cycle progression in small cell lung carcinoma (SCLC) cells. We also demonstrated that SCLC cells express both CaM kinasc type II (CaMKII) and CaM kinase type IV (CaMKIV). Five independent SCLC cell lines expressed proteins reactive with antibody to the CaMKII 0 subunit, but none expressed detectable proteins reactive with antibody to the CaMKII 6 subunit. All SCLC cells lines tested expressed both the 6 and 13 isoforms of CaMKIV Immunoprecipitation of CaMKII from SCLC cells yielded multiple proteins that autophosphorylated in the presence of Ca’+lcalmodulin. Autophosphorylation was inhibited by the CaMKII(281-302) peptide. which corresponds to the CaMKII autoinhibitory domain, and by I- [N,O-bis(S-isoquinolinesulfonyl)-N-methyz ine (KN-62). a specific CaM kinasc antagonist. Influx of Cal+ through voltage-gated Car’ channels stimulated phosphotylation of CaMKIl in SCLC cells, and this was inhibited by KN-62. Incubation of SCLC cells with KN-62 potently inhibited DNA synthesis, and slowed progression through S phase. Similar anti-proliferative effects of KN- 62 occurred in SK-N-SH human neuroblastoma cells, which express both CaMKII and CaMKIV, and in K562 human chronic myelogenous Ieukemia cells, which express CaMKII but not CaMKIV. The expression of both CaMKII and CaMKIV by SCLC cells, and the sensitivity of these cells to tbe anti-proliferative effects of KN-62, suggest a role for CaM kinase in regulating SCLC proliferation.

Effect of tyrphostin combined with a substance P related antagonist on small cell lung cancer cell growth in vitro Seek1 MJ, Rozengurt E. Imperial Cancer Reseanh Fund, 44 Lincoln j Inn Fields, London WCZA 3P.Y. Em J Cancer Part A Gen Top 1996;32:342-5.

The protein tyrosine kinase inhibitor [(3,4,5,-trihydroxyphenyl)- methylenej-propanedinitrile (tyrphostin) was originally designed to inhibit polypeptide growth factor receptor signalbng, but was also found to inhibit neuropeptide stimulated tyrosine phosphorylation and mitogenesis in Swiss 3T3 cells [J Biol Chem 1993. 268, 9548-95541. Here, we demonstrate that tyrphostin inhibits in vitro colony growth of the H-345 and H-69 small cell lung cancer (SCLC) cell lines stimulated by the neuropcptides. bombesin and bradykinin. respectively. This effect was dose-dependent and, at tyrphostin concentrations above 5 iM, both background and neuropeptide stimulated colony formation were reduced. In liquid culture, tyrphostin inhibited the growth of the H-345 and H- 69 SCLC cell lines with an IC,, of 7 IM. Time course experiments in liquid culture revealed that tyrphostin delayed the rate of entry of both SCLC cell lines into rapid phase growth and reduced the number of cells reaching a plateau phase of growth compared with control cells. Furthermore, tyrphostin concentrations at or above 50 iM reduced the number ofcells present over time compared with untreated cells. When combined with a substance P (SP) anaIogue, which inhibits the action of multiple neuropeptides and SCLC cell growth, both in semisolid media and liquid culture, tyrphostin additively inhibited the growth of the H-345 and H-69 SCLC cell lines in liquid culture.

p53 Mutations in non-small cell lung carcinomas in Hong Kong Maria Li Lung. Wong MP, Skaanild MT, Fok CL, Wah Kit Lam. Wing Wai Yew. Department of Biologv, Hong Kong Scienceflechnologv Univ., Clear Water Bqv, Kowloon. Chest 1996;109:718-726.

Lung resections from 50 Chinese patients in Hong Kong diagnosed as having non-small cell lung carcinoma were examined for the presence of mutations in the ~53 gene by polymerase chain reaction single- stranded conformation polymorphism methods and for aberrant protein expression by immunostaining techniques. Eight-point mutations in the evolutionarily conserved exon 5 through 8 regions were detected.

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c-myc antisense oligodeoxyribonucleotides inhibit proli-feration of non-small cell lung cancer Robinson LA, Smith LJ, Fontaine MP, Kay HD, Mountjoy CP, Pirruccello SJ H. Lee Mojitt Cancer Centec Research Institute, 12902 Magnolia Dr, Tampa, FL 33612-9497. AnnThorac Surg 1995;60: 1583- 91.

Background. Mutation or deregulation of certain cellular genes (protooncogenes) results in expression of proteins that appear to promote mahgnant transformation. Human non-small cell lung cancer has been documented to express many such oncogenes including c-myc, bcl-2, and mutant ~53. Antisense oligo-deoxyribonucleotides (ASODN) compIementaty to these oncogenes were tested on three non-small cell lung cancer cell lines for their efficacy in inhibiting cellular proliferation and oncoprotein expression. Methods. Established non-small cell lung cancer cell lines A427, SKMES- I, and A549 were grown in the presence of ASODNs complementary to messenger RNA of c-myc. bcl-2, ~53,