Mechanism of benzo(a)pyrene induction of alpha-human chorionic gonadotropin gene expression in human lung tumor cells

Usefulness of argyrophilic nucleolar organizer regions in detection of lung cells alterations after benzo[a]pyrene instillation

PURPOSE: To verify the relationship between AgNOR expression and lung tissues changes of Wistar rats after pulmonary instillation of benzo[a]pyrene (B[a]P). METHODS: Male Rattus norvegicus albinus,Wistar lineage were given a single intrapulmonary instillation of B[a]P at doses of 10 and 20 mg/kg in a volume of approximately 0,3 ml. After 7 and 21 days the rats were killed and the lung slices submitted to a histological technique of AgNOR. AgNOR dots were quantified and the result analyzed by statistical tests; p <= 0,05 was considered significant. RESULTS: The mean values of AgNOR dots for the experimental groups 10/7 (1,51±0,86) and 10/21 (1,84±0,13) were statistically different (p = 0,009). Among the groups 20/7 (1,63±0,11) and 20/21 (2,48±0,28) was observed statistically significant difference (p = 0,003). CONCLUSION: The AgNOR technique can be useful in identification of cells changes induced by B[a]P.

Human eosinophils express transforming growth factor alpha

Transforming growth factor alpha (TGF-alpha) is a pleuripotential cytokine with diverse biological effects, including the ability to influence the proliferation of normal cells or neoplastic epithelial cells. Eosinophils are a subset of granulocytes that normally enter the peripheral tissues, particularly those beneath gastrointestinal, respiratory, and urogenital epithelium, where they reside in close proximity to the epithelial elements. In this study, we demonstrate that the great majority of eosinophils infiltrating the interstitial tissues adjacent to two colonic adenocarcinomas and two oral squamous cell carcinomas labeled specifically by in situ hybridization with a 35S-riboprobe for human TGF-alpha (hTGF-alpha). No other identifiable leukocytes in these lesions contained detectable hTGF-alpha mRNA. We also examined leukocytes purified from a patient with the idiopathic hypereosinophilic syndrome. 80% of these eosinophils, but none of the patient's neutrophils or mononuclear cells, were positive for hTGF-alpha mRNA by in situ hybridization, and 55% of these eosinophils were positive by immunohistochemistry with a monoclonal antibody directed against the COOH terminus of the mature hTGF-alpha peptide. Finally, the identification of the purified eosinophil-associated transcript as hTGF-alpha was confirmed by polymerase chain reaction product restriction enzyme analysis followed by Southern blot hybridization. In contrast to eosinophils from the patient with hypereosinophilic syndrome, the peripheral blood eosinophils from only two of seven normal donors had detectable TGF-alpha mRNA and none of these eosinophils contained immunohistochemically detectable TGF-alpha product. Taken together, these findings establish that human eosinophils can express TGF-alpha, but suggest that the expression of TGF-alpha by eosinophils may be under microenvironmental regulation. Demonstration of TGF-alpha production by tissue-infiltrating eosinophils and the eosinophils in the hypereosinophilic syndrome identifies a novel mechanism by which eosinophils might contribute to physiological, immunological, and pathological responses.

Histone gene (H3) expression in chemically transformed oral keratinocytes

The hamster cheek pouch is an excellent target tissue for the experimental study of oral carcinogenesis. In the course of searching for molecular alterations during the malignant transformation process, the necessity for a molecular marker for cellular proliferation became apparent. In this report, we show that the cellular level of the histone H3 mRNA is valid as a molecular index of proliferation for cycling cell populations. H3 is known to be proliferation dependent for its expression in cultured animal cells. This study shows that H3 retains its cell-cycle-dependent expression in chemically transformed oral keratinocytes. The onset of H3 mRNA synthesis couples to the onset of DNA synthesis (S-phase). The cellular level of H3 mRNA therefore is proportional to the fraction of cells in the S-phase of the cell cycle. This conveniently allows us to correlate, in asynchronized cell populations, the expression of cellular genes to their proliferation rates. We demonstrate the usefulness of this proliferation marker by presenting data that different chemically induced oral carcinomas, but not normal cheek pouch tissues, contain readily detectable levels of c-Ki-ras proto-oncogene mRNA. Probing the same RNA blot to quantitate H3 mRNA levels allowed us to conclude that the high levels of c-Ki-ras mRNA in tumor tissues was likely due to the increased growth rate of the tumor tissues and not due to the deregulated expression of this cellular-proto-oncogene.

Characterization of the state of differentiation of six newly established human non-small-cell lung cancer cell lines

Six new non-small-cell lung cancer (NSCLC) cell lines were established directly from human tissue or indirectly via nude mouse xenografts in serum-supplemented media with success rates of 8% and 13%, respectively. They comprised one adenocarcinoma (ADLC-5M2), two squamous cell carcinomas (EPLC-32M1, EPLC-65H), two large cell carcinomas (LCLC-97TM1, LCLC-103H), and one malignant biphasic mesothelioma (MSTO-211H). All cell lines grew adherent to culture vessels with population doubling times (PDT) of 16-40 h, formed colonies in soft agarose with efficiencies of 0.1%-5.1%, and all grew in athymic nude mice. Xenograft histologies appeared as follows: (a) undifferentiated carcinomas with feeble resemblance to the original tumors in the case of adenocarcinomas and squamous cell carcinomas; (b) large cell carcinoma with high resemblance to the original tumor; (c) an undifferentiated tumor with predominance of large epithelial cells and few fibrous cells in the case of mesothelioma. Human chorionic gonadotropin (HCG) was found by radioimmunoassay and high-affinity binding sites for epidermal growth factor (EGF) by radio-receptor assay in 4/4 cell lines. A very low activity of L-DOPA decarboxylase (DDC) was detectable only in the adenocarcinoma cell line. All cell lines overexpressed the c-myc protooncogene, and no gene rearrangement or amplification was observed. Chromosome analysis revealed modal chromosome numbers of 70-73 in ADLC-5M2, EPLC-32M1, EPLC-65H, and MSTO-211H. Cell lines derived from large cell carcinoma had modal values of 65 and 170 and a wider chromosome distribution than all other cell lines. A NSCLC specific chromosomal aberration has been undetectable until now. These cell lines may aid in elucidating the biology of NSCLC and its interrelationship to other lung tumors.