Differential antitumor effects of vitamin D analogues on colorectal carcinoma in culture.

Colorectal cancer (CRC) is an emerging global problem with the rapid increase in its incidence being associated with an unhealthy lifestyle. Epidemiological studies have shown that decreased levels of vitamin D3 significantly increases the risk of CRC. Furthermore, negative effects of vitamin D3 deficiency can be compensated by appropriate supplementation. Vitamin D3 was shown to inhibit growth and induce differentiation of cancer cells, however, excessive vitamin D3 intake leads to hypercalcemia. Thus, development of efficient vitamin D3 analogues with limited impact on calcium homeostasis is an important scientific and clinically relevant task. The aims of the present study were to compare the antiproliferative potential of classic vitamin D3 metabolites (1α,25(OH)2D3 and 25(OH)D3) with selected low calcemic analogues (calcipotriol and 20(OH)D3) on CRC cell lines and to investigate the expression of vitamin D-related genes in CRC cell lines and clinical samples. Vitamin D3 analogues exerted anti-proliferative effects on all CRC cell lines tested. Calcipotriol proved to be as potent as 1α,25(OH)2D3 and had more efficacy than 20-hydroxyvitamin D3. In addition, the analogs tested effectively inhibited the formation of colonies in Matrigel. The expression of genes involved in 1α,25(OH)2D3 signaling and metabolism varied in cell lines analysed, which explains in part their different sensitivities to the various analogues. In CRC biopsies, there was decreased VDR expression in tumor samples in comparison to the surgical margin and healthy colon samples (p<0.01). The present study indicates that vitamin D3 analogues which have low calcemic activity, such as calcipotriol or 20(OH)D3, are very promising candidates for CRC therapy. Moreover, expression profiling of vitamin D-related genes is likely to be a powerful tool in the planning of anticancer therapy. Decreased levels of VDR and increased CYP24A1 expression in clinical samples underline the importance of deregulation of vitamin D pathways in the development of CRC.

Lack of the SOX9 gene polymorphism in sex reversal dogs (78,XX; SRY negative).

The molecular background of the most frequent intersexuality syndrome in dogs (female-to-male sex reversal with the female karyotype and a lack of the SRY gene) is unknown. In this article, new cases of this syndrome are described in two unrelated American Staffordshire terrier dogs and one miniature pinscher dog subjected to cytogenetic and molecular analysis due to the presence of an enlarged clitoris. One dog was operated on and histological studies of the gonads revealed a testicular structure without signs of spermatogenesis, but the uterus wall appeared to be normal. All three dogs had female chromosome complements and lacked the Y-linked genes SRY and ZFY. Eight fragments, representing the vast majority of the coding sequence of the SOX9 gene, and two fragments of the 5' flanking region of this gene were analyzed. The studied fragments had identical DNA sequences when comparing the intersexual dogs with GenBank sequences (AY237827; NW139883). Thus a mutation in the coding sequence as well as the promoter region of the SOX9 gene might be excluded as a cause of this type of intersexuality. The importance of further studies of the 5' flanking region of this gene is discussed.

Application of FISH and Q-PCR techniques in breakpoint diagnostics in three cases of marker chromosomes derived from chromosome 15.

BACKGROUND: The goal of the study was a search for effective methods of diagnosing additional marker chromosomes. MATERIAL AND METHODS: Three cases of extra structurally abnormal chromosomes (ESACs) were diagnosed, the ESACs having been derived from chromosome 15 by cytogenetic techniques, the fluorescence in situ hybridisation (FISH) technique and the quantitative--polymerase chain reaction (Q-PCR). An application of a set of commercially available probes, specific for the 15q11.2-q12 regions (PWACR-Prader-Willi/Angelman Critical Region) allowed for a description of the breaking points. RESULTS: The presence of PWACR region was confirmed in one case and excluded in the other two. It was also attempted to apply the Q-PCR technique for a more accurate determination of the size of the region involved in chromosomal aberration, what would allow for a more reliable prognosing of the clinical outcome. In one of the patients, the breaking point was localized as distal to D15S144 locus, while it was proximal to D15S11 locus in the two remaining cases. CONCLUSIONS: The obtained results demonstrate a possibility of using the Q-PCR method in diagnosing unbalanced chromosome aberrations.

The quantitative PCR technique resolves ambiguities concerning a small rearrangement of human chromosome 6q12-13.

Karyotype analysis, performed on the basis of chromosome banding pattern, is a standard method used for identification of chromosomal aberrations, both numerical and structural. The application of classic cytogenetic techniques fails, however, to solve all diagnostic problems in certain types of chromosome aberrations. In this study, quantitative polymerase chain reaction technique (Q-PCR) application was applied to verify a cytogenetic diagnosis, which assumed that a difference observed in the banding pattern of homologous chromosome 6q12-13 region of a foetus had resulted from an inversion and/or duplication of the region in question. The obtained results indicate a possibility to use the Q-PCR method in the diagnostics of unbalanced chromosomal aberrations.