Galactosylceramide Upregulates the Expression of the BCL2 Gene and Downregulates the Expression of TNFRSF1B and TNFRSF9 Genes, Acting as an Anti-Apoptotic Molecule in Breast Cancer Cells.

Galactosylceramide (GalCer) increases the resistance of breast cancer cells to doxorubicin, paclitaxel, and cisplatin by acting as an anti-apoptotic molecule. GalCer was found to specifically downregulate the levels of the pro-apoptotic TNFRSF1B and TNFRSF9 genes and upregulate the levels of the anti-apoptotic BCL2 gene, suggesting that this glycosphingolipid regulates their expression at the transcriptional level. Consistent with this hypothesis, MDA-MB-231 and MCF7 breast cancer cells with high levels of GalCer showed lower activity of the TNFRSF1B and TNFRSF9 promoters than cells lacking GalCer. In contrast, the activity of the BCL2 promoter was higher in MCF7 cells overproducing GalCer than in MCF7 cells without GalCer. However, no difference in BCL2 promoter activity was observed between MDA-MB-231 cells with high and no GalCer content. Instead, we found that high levels of GalCer increased the stability of Bcl-2 mRNA. Subsequent studies showed that breast cancer cells with high levels of GalCer are characterized by significantly lower expression of P53. Importantly, inhibition of P53 expression by siRNA in MCF7 and MDA-MB-231 cells lacking GalCer resulted in decreased expression and promoter activity of the TNFRS1B and TNFRSF9 genes. On the other hand, increased expression and promoter activity of the BCL2 gene was found in such MCF7 cells, and increased stability of Bcl-2 transcripts was observed in such MDA-MB-231 cells. Taken together, these data strongly suggest that the regulatory protein that simultaneously increases the expression of the TNFRSF1B and TNFRSF9 genes and decreases the expression of the BCL2 gene and the stability of Bcl-2 transcripts is most likely P53, the expression of which is GalCer dependent.

Syntheses and cytotoxicity of phosphatidylcholines containing ibuprofen or naproxen moieties.

In this study, novel phosphatidylcholines containing ibuprofen or naproxen moieties were synthesized in good yields and high purities. Under the given synthesis conditions, the attached drug moieties racemized, which resulted in the formation of phospholipid diastereomers. The comperative studies of the cytotoxicity of ibuprofen, naproxen and their phosphatidylcholine derivatives against human promyelocytic leukemia HL-60, human colon carcinoma Caco-2, and porcine epithelial intestinal IPEC-J2 cells were carried out. The results of these studies indicated that phospholipids with NSAIDs at both sn-1 and sn-2 positions (15 and 16) were more toxic than ibuprofen or naproxen themselves, whereas 2-lysophosphatidylcholines (7 and 8) were less toxic against all tested cell lines. Phospholipids with NSAIDs at sn-1 and palmitic acid at sn-2 (9 and 10) were also less toxic against Caco-2 and normal cells (IPEC-J2).

Sulfatide decreases the resistance to stress-induced apoptosis and increases P-selectin-mediated adhesion: a two-edged sword in breast cancer progression.

BACKGROUND: We have previously shown that galactosylceramide (GalCer) affects the tumourigenic and metastatic properties of breast cancer cells by acting as an anti-apoptotic molecule. Since GalCer is a precursor molecule in the synthesis of sulfatides, the present study was aimed to define the role of sulfatides in apoptosis and breast cancer progression. METHODS: Expression of GAL3ST1 in breast cancer cell lines and breast cancer tissue specimens was analysed using real-time PCR, western blotting and immunohistochemistry analysis. The amount of sulfatide, GalCer and ceramide was analysed by thin-layer chromatography binding assay and by the modified hydrophilic interaction liquid chromatography coupled with electrospray mass spectrometry methodology. The tumourigenicity of cancer cells was analysed by an in-vivo tumour growth assay. Apoptotic cells were detected based on caspase-3 activation and the TUNEL assay. The interaction of breast cancer cells with P-selectin or E-selectin was analysed using the flow adhesion assay. The ability of sulfatide-expressing cells to activate and aggregate platelets was studied using the flow-cytometry-based aggregation assay. RESULTS: Using two models of breast cancer, T47D cells with blocked synthesis of sulfatide and MDA-MB-231 cells with neosynthesis of this glycosphingolipid, we showed that high sulfatide levels resulted in increased sensitivity of cancer cells to apoptosis induced by hypoxia and doxorubicin in vitro, and decreased their tumourigenicity after transplantation into athymic nu/nu mice. Accordingly, a clinical study on GAL3ST1 expression in invasive ductal carcinoma revealed that its elevated level is associated with better prognosis. Using MDA-MB-231 cells with neosynthesis of sulfatide we also showed that sulfatide is responsible for adhesion of breast cancer cells to P-selectin-expressing cells, including platelets. Sulfatide also acted as an activating molecule, increasing the expression of P-selectin. CONCLUSIONS: This study demonstrates that increased synthesis of sulfatide sensitises cancer cells to microenvironmental stress factors such as hypoxia and anticancer drugs such as doxorubicin. However, sulfatide is probably not directly involved in apoptotic cascades, because its increased synthesis by GAL3ST1 decreased the amounts of its precursor, GalCer, a known anti-apoptotic molecule. On the other hand, our data support the view that sulfatides are malignancy-related adhesive molecules involved in activating and binding P-selectin-expressing platelets to breast cancer cells.

[Prevalence of Lyme disease among forestry workers]. / Ocena czestosci wystepowania boreliozy wsród pracowników lesnictwa.

BACKGROUND: The aim of the study is to assess the incidence of Lyme disease, established diagnosis based on medical history and clinical symptoms, serology, duration of exposure in the workplace and occupational disease certification among forestry workers in selected districts of the Warmia and Mazury region. MATERIAL AND METHODS: The study consisted of annual screening of 332 employees in 6 forest districts under the supervision of the Health Center Medica in Ostróda. Serological tests were performed in all serum samples and IgG and IgM antibodies were determined by ELISA test. Positive results were confirmed by Western-blot test. Diagnosis was made based on medical history and clinical symptoms. Results were presented by the division of selected forest districts, gender, duration of exposure in the workplace and genospecies of spirochete Borrelia responsible for the disease development. RESULTS: Lyme disease incidence was found in all selected forest districts. Positive results in Western-blot test were determined in 120 people (63.1% of all the surveyed). However, after taking a detailed medical history of the patients Lyme disease was diagnosed in 91 people which makes 27.4% of all the examined. Among patients with diagnosed disease, IgG antibodies were found in 76 people, IgM in 25 people, while both IgM and IgG in 10 people. There was also variation in the involvement of genospecies generating the disease; spirochete B. afzeli--46% for IgG antibodies, whereas spirochete B. burgdorferi--50% of all cases for IgM antibodies. At the same time the relationship between the extended duration of occupational exposure to tick bites and the increased incidence of Lyme disease was confirmed, indicating the group of workers employed for at least 25 years. CONCLUSIONS: Forestry districts of the Warmia and Mazury region, creates extremely dangerous occupational conditions because of exposure to tick bites. At the same time the duration of employment significantly increases the risk of Lyme. The analysis of serological tests results indicated differences in the reactivity of IgG and IgM classes and confirmed the correlation between clinical symptoms of Lyme disease and the variation of genospecies inducing the disease.