BRCA1 loss preexisting in small subpopulations of prostate cancer is associated with advanced disease and metastatic spread to lymph nodes and peripheral blood.

PURPOSE: A preliminary study performed on a small cohort of multifocal prostate cancer (PCa) detected BRCA1 allelic imbalances among circulating tumor cells (CTC). The present analysis was aimed to elucidate the biological and clinical roles of BRCA1 losses in metastatic spread and tumor progression in PCa patients. EXPERIMENTAL DESIGN: To map molecular progression in PCa outgrowth, we used fluorescence in situ hybridization analysis of primary tumors and lymph node sections, and CTCs from peripheral blood. RESULTS: We found that 14% of 133 tested patients carried monoallelic BRCA1 loss in at least one tumor focus. Extended molecular analysis of chr17q revealed that this aberration was often a part of larger cytogenetic rearrangement involving chr17q21 accompanied by allelic imbalance of the tumor suppressor gene PTEN and lack of BRCA1 promoter methylation. The BRCA1 losses correlated with advanced T stage (P < 0.05), invasion to pelvic lymph nodes (P < 0.05), as well as biochemical recurrence (P < 0.01). Their prevalence was twice as high within 62 lymph node metastases (LNM) as in primary tumors (27%, P < 0.01). The analysis of 11 matched primary PCa-LNM pairs confirmed the suspected transmission of genetic abnormalities between these two sites. In four of seven patients with metastatic disease, BRCA1 losses appeared in a minute fraction of cytokeratin- and vimentin-positive CTCs. CONCLUSIONS: Small subpopulations of PCa cells bearing BRCA1 losses might be one confounding factor initiating tumor dissemination and might provide an early indicator of shortened disease-free survival.

The profile of ErbB/Her family genes copy number assessed by real-time PCR in parathyroid adenoma and hyperplasia associated with sporadic primary hyperparathyroidism.

Hyperparathyroidism (pHPT) is a relatively frequent endocrinopathy, however, the molecular mechanisms of its etiology remain poorly understood. This disorder is mainly associated with benign tumours (adenoma) and hyperplasia of the parathyroid, hence, the focus is directed also to genes that are likely to be involved in carcinogenesis. Among such genes are ErbB/Her family genes already used in diagnosis of other tumours (e.g., breast carcinoma) and reported also to play a role in development of endocrine lesions. So far, ErbB-1/Her-1/EGFR expression has been detected in pHPT-associated adenomas and hyperplasia as opposed to no expression in normal parathyroid tissue. Moreover, losses or gains of the fragments of chromosomes where ErbB/Her genes are located have been reported. In this study, the gene dosage of ErbB/Her family genes were determined for the first time in parathyroid adenomas, hyperplasia and morphologically unchanged tissue in order to establish their putative role in the development of the disease. Genomic DNA was isolated from 33 patients with sporadic hyperparathyroidism and the gene copy numbers were assessed using real-time PCR. The ErbB/Her genes' profile was unaltered in most of the examined samples. Two low-level amplifications of ErbB-1/Her-1/EGFR gene, two deletions of ErbB-2/Her-2, and six deletions of ErbB-4/Her-4 were found. The ErbB-3/Her-3 gene remained unaffected. No correlation with clinical parameters was found for any gene. Both the low number of alterations and a lack of their associations with clinical parameters exclude the prognostic value of the ErbB/Her genes family in parathyroid tumourigenesis. Nevertheless, the ErbB-4/Her-4 deletions seem to be interesting for further investigations, especially in the context of PTH secretion.

[Housekeeping genes as a reference in quantitative real-time RT-PCR]. / Geny metabolizmu podstawowego jako geny referencyjne w ilosciowym oznaczaniu ekspresji genów metoda real-time PCR.

The determination of gene expression levels in normal tissue is necessary for the analysis and interpretation of results of gene profiling studies in pathological samples. With the real-time reverse transcription-PCR technique, which enables one to detect the amplification rate during the process, assessment of the amount of gene transcript is fast and accurate. The most important problem in this type of analysis is the variability in the amount of genetic material between samples, caused mostly by changes in the efficiency of mRNA isolation and reverse transcription. Therefore, a reference gene to normalize sample variations is required. Quantification of the mRNA of the target and the reference gene in the sample ensures that the changes in transcript levels will influence both genes equally. To be used as a reference, a gene should show stable, unregulated expression in the analyzed sample type. Housekeeping genes (HKGs) fulfill this criterion and they are used for normalization purposes in most expression studies. However, transcript levels of HKGs can vary between different types of tissue (normal and pathological samples) and under different treatment conditions (drugs and chemicals). The aim of this study was to show the differences and the factors which can influence housekeeping gene expressions.

Protoporphyrin IX induces apoptosis in HeLa cells prior to photodynamic treatment.

Photodynamic therapy (PDT) combining treatment with a light-excited compound and laser light induction, via cellular ROS generation, kills cancer cells by damaging organelles and impairing metabolic pathways. As the exact mechanisms underlying cancer cell death due to PDT treatment remain controversial, the influence of photosensitizer itself, protoporphyrin IX (PpIX) on cancer cells was investigated. The concentration-dependent viability of HeLa cells was estimated after PpIX-treatment. Microscopic analyses revealed that treated cells exhibited apoptosis-like morphology: blebbing, chromatin condensation, nuclear fragmentation, asymmetry of cellular membrane. These results shed a new light on cancer cell death due to PDT because they showed that PpIX can induce apoptosis without light excitation.

Tumor suppressor Fhit protein interacts with protoporphyrin IX in vitro and enhances the response of HeLa cells to photodynamic therapy.

Fhit, the product of tumor suppressor fragile histidine triad (FHIT) gene, exhibits antitumor activity of still largely unknown cellular background. However, it is believed that Fhit-Ap(3)A or Fhit-AMP complex might act as a second class messenger in cellular signal transduction pathway involved in cell proliferation and apoptosis. We demonstrate here for the first time that the photosensitizer, protoporphyrin IX (which is a natural precursor of heme) binds to Fhit protein and its mutants in the active site in vitro. Furthermore, PpIX inhibits the enzymatic activity of Fhit. Simultaneously, PpIX shows lower binding capacity to mutant Fhit-H96N of highly reduced hydrolase activity. In cell-based assay PpIX induced HeLa cell death in Fhit and Fhit-H96N-dependent manner which was measured by means of MTT assay. Moreover, HeLa cells stably expressing Fhit or mutant Fhit-H96N were more susceptible to protoporphyrin IX-mediated photodynamic therapy (2J/cm(2)) than parental cells.