Amplification and expression of splice variants of the gene encoding the P450 cytochrome 25-hydroxyvitamin D(3) 1,alpha-hydroxylase (CYP 27B1) in human malignant glioma

Abstract

PURPOSE: Recently, we reported the isolation of six novel genes termed glioma-amplified sequences (GASs) from the glioblastoma cell line TX3868 using microdissected mediated cDNA capture (U. Fischer et al., HUM: MOL: GENET:, 5: 595-600, 1996). The aim of this study was to further characterize the gene GAS89.

EXPERIMENTAL DESIGN: To determine the amplification frequency, we performed comparative PCR studies and Southern blot hybridization experiments. To identify full-length clones of GAS89 we screened a HybriZAP library. Reverse transcription-PCR was performed to isolate splice variants and to determine expression levels.

RESULTS: We identified for the gene GAS89 an amplification frequency of 25% in 28 examined glioblastoma multiforme samples. Screening a HybriZAP library, we isolated an incomplete gene sequence showing identity with the gene for 25-hydroxyvitamin D(3) 1,alpha-hydroxylase. Different full-length clones were then isolated using PCR primers chosen from the 3'- and 5'-untranslated regions. As determined by sequencing, the clones represent various splice variants of the 25-hydroxyvitamin D(3) 1,alpha-hydroxylase gene. The clones encode truncated proteins but also one potentially functional enzyme variant. Reverse transcription-PCR studies revealed overexpression of several variants in glioblastoma samples with GAS89 amplification in comparison with normal brain RNA and glioblastoma without GAS89 amplification.

CONCLUSIONS: This is the first report of gene amplification for 25-hydroxyvitamin D(3) 1,alpha-hydroxylase and the appearance of mRNA splice variants in glioblastoma multiforme. The endogenous expression of the 25-hydroxyvitamin D(3) 1,alpha-hydroxylase gene and the appearance of alternative splice variants reveal a new feature of the molecular pathogenesis of glioblastoma and may represent a new target for glioma therapy.

About this publication.

See also:

- Vitamin D (analogues and/or derivatives) and cancer;

- All-Trans-Retinoic Acid (ATRA - analogues and/or derivatives);

- Solution of retinoids in vitamin E in the Di Bella Method biological multitherapy;

- Recurrent Glioblastoma Multiforme (grade IV – WHO 2007): a case of complete objective response achieved by means of the concomitant administration of Somatostatin and Octreotide – Retinoids – Vitamin E – Vitamin D3 – Vitamin C – Melatonin – D2 R agonists (Di Bella Method – DBM) associated with Temozolomide;

- Congenital fibrosarcoma in complete remission with Somatostatin, Retinoids, Vitamin D3, Vitamin E, Vitamin C, Melatonin, Calcium, Chondroitin sulfate associated with low doses of Cyclophosphamide in a 14-year Follow Up;

- The Di Bella Method (DBM) in the treatment of prostate cancer: a preliminary retrospective study of 16 patients and a review of the literature;

- Cyclophosphamide plus Somatostatin, Bromocriptin, Retinoids, Melatonin and ACTH in the Treatment of Low-grade Non-Hodgkin’s Lymphomas at Advanced Stage: Results of a Phase II Trial;

- Relapse of High-Grade Non-Hodgkin’s Lymphoma After Autologous Stem Cell Transplantation: A Case Successfully Treated With Cyclophosphamide Plus Somatostatin, Bromocriptine, Melatonin, Retinoids, and ACTH;

- Low-grade Non-Hodgkin Lymphoma at Advanced Stage: A Case Successfully Treated With Cyclophosphamide Plus Somatostatin, Bromocriptine, Retinoids, and Melatonin;

- The Di Bella Method (DBM) improved survival, objective response and performance status in a retrospective observational clinical study on 55 cases of Lymphomas;

- Large B-cells Non-Hodgkin's Lymphoma, Stage IV-AE: a Case Report;

- Non-Hodgkin's Lymphoma, Stage III-B-E: a Case Report;

- Somatostatin, retinoids, melatonin, vitamin D, bromocriptine, and cyclophosphamide in advanced non-small-cell lung cancer patients with low performance status;

- Somatostatin, retinoids, melatonin, vitamin D, bromocriptine, and cyclophosphamide in chemotherapy-pretreated patients with advanced lung adenocarcinoma and low performance status;

- Observations on the Report of a case of pulmonary adenocarcinoma with lymph node, hepatic and osseus metastasis;

- Evaluation of the safety and efficacy of the first-line treatment with somatostatin combined with melatonisn, retinoids, vitamin D3, and low doses of cyclophosphamide in 20 cases of breast cancer: a preliminary report;

- The Di Bella Method (DBM) improved survival, objective response and performance status in a retrospective observational clinical study on 122 cases of breast cancer;

- Complete objective response to biological therapy of plurifocal breast carcinoma.