These results indicate that the tumour suppressor properties of Fhit are strictly related to its expression level and show that the Fhit protein has a dose-dependent antiproliferative effect on the Fhit-negative Calu-1 lung cancer cell line.
We examined aberrant expression of the Fhit protein and allele loss at the FHIT gene in a series of lung cancer cases, mainly of non-small cell carcinoma (NSCLC) histology.
The coincidence of a chromosomal fragile site, FRA3B, at a common chromosomal breakpoint in lung cancer has suggested that fragility at this site may predispose to breakage that could contribute to multistep carcinogenesis.
In this report, we describe an improved extruded DOTAP:cholesterol (DOTAP:Chol) cationic liposome that efficiently delivers therapeutic tumor suppressor genes p53 and FHIT, which are frequently altered in lung cancer, to localized human primary lung cancers and to experimental disseminated metastases.
All of these findings are consistent with loss of Fhit protein expression being as frequent an abnormality in lung cancer pathogenesis as are p53 and p16 protein abnormalities and that such loss occurs independently of the commitment to the metastatic state and of most other molecular abnormalities.
We analyzed FHIT gene aberrations in 64 lung cancer tissues and found that the appearance of the aberrant FHIT transcripts depends on the condition of RT-PCR and high telomerase activity, shortened telomere length, and advanced pathological stage were likely associated with the prevalence of aberrant FHIT transcripts, but not with allelic loss of the FHIT gene.
To assess the frequency and specificity of inactivation and its relevance in a clinical setting, we have produced antibodies against the Fhit protein and studied its expression in a series of non-small cell lung cancers and normal bronchial mucosa and a spectrum of preinvasive lesions by immunohistochemistry.
Our findings support the conclusion that FHIT/FRA3B abnormalities are associated with lung cancer pathogenesis but that FHIT abnormalities differ from the types of mutations and lack of wild-type transcript found in classic tumor suppressor genes, and functional studies are needed to define the role of FHIT in thoracic tumorigenesis.
Normal FHIT transcripts in renal cell cancer- and lung cancer-derived cell lines, including a cell line with a homozygous deletion in the FRA3B region.
Small cell lung tumors (80%) and non-small cell lung cancers (40%) showed abnormalities in RNA transcripts of FHIT, and 76% of the tumors exhibited loss of FHIT alleles.
To avoid overlooking tumor-specific altered transcripts due to contaminating normal cells in primary tumors, FHIT alterations were examined in 41 lung cancer cell lines in the present study.