Analysis of vitamin D-receptor (VDR) and retinoid X-receptor alpha in breast cancer.

The expression of vitamin D-receptor (VDR) and retinoid X-receptor alpha (RXR-alpha) has been analysed immunohistochemically in benign (n = 62 and n = 5 respectively) and malignant (n = 228 and n = 15 respectively) breast tissue samples using a monoclonal antibody 9A7gamma against VDR and a polyclonal antibody against RXR-alpha. A recently developed immunoreactive scoring method (IRS) was employed. The expression of VDR was detected at the RNA-level using the reverse transcriptase-polymerase chain reaction. A statistically significant higher expression of VDR at the protein level was seen in breast cancer compared with benign breast tissue, whereas at the mRNA level no visible differences in the expression of VDR were found. A higher expression of RXR-alpha was seen in breast cancer compared with benign breast tissue. Our findings indicate that breast tissue may be a new target organ for therapeutically applied vitamin D and retinoid analogues. VDR and RXR-alpha are upregulated at the protein level in breast carcinomas as compared to normal breast tissue, indicating a possibly increased sensitivity to therapeutically applied vitamin D analogues. New vitamin D analogues exerting less calcemic side effects may be promising new drugs for the treatment or chemoprevention of breast carcinomas as well as of precancerous breast lesions. Combination therapies of vitamin D and retinoid analogues with fewer side effects seen promising for the treatment of breast cancer.

Immunohistochemical analysis of 1,25-dihydroxyvitamin-D3-receptors, estrogen and progesterone receptors and Ki-67 in ovarian carcinoma.

BACKGROUND: The aim of this study was to analyze immunohistochemically the expression of VDR in normal and carcinomatous ovarian tissue to evaluate whether ovarian tissue may be a new potential target for biologically active vitamin D analogues. MATERIALS AND METHODS: The expression of 1,25-dihydroxyvitamin-D3-receptors (VDR) was immunohistochemically investigated in ovarian carcinomas (n=40). VDR immunoreactivity (mAb 9A7gamma) was compared with the staining pattern of the proliferation marker Ki-67, of the estrogen receptors (ER) and of the progesterone receptors (PR). The percentage of positive tumour cells (PP), the intensity of staining (SI) and a resulting immunoreactivity score (IRS) were determined for the semiquantitative evaluation of VDR-, ER- and PR-expression. RESULTS: A total of 16.7% of the normal surface ovarian epithelium was VDR-negative, while the remaining 83.3% revealed weak to moderate VDR immunoreactivity. Moderate to strong nuclear immunoreactivity for VDR was detected in almost all ovarian carcinomas analyzed. Both the intensity of VDR immunostaining and the number of VDR-positive cells were significantly increased in ovarian carcinomas as compared to normal ovarian tissue. Analyzing coexpression of VDR with the proliferation marker Ki-67 or with the estrogen and progesterone receptors, no significant correlation was found. CONCLUSION: Our findings indicate that: (I) VDR expression is increased in ovarian carcinomas as compared to normal ovarian tissue. (II) Up-regulation of VDR in ovarian carcinomas is not exclusively induced by an increase of proliferation, but by different unknown mechanisms. (III) Expression of VDR in ovarian carcinomas is independently regulated from the expression of ER and PR. (IV) Ovarian tissue may be a new target organ for therapeutically applied vitamin D analogues exerting fewer calcemic side-effects. New vitamin D analogues may be promising drugs for the treatment of advanced ovarian carcinomas.

Vitamin D receptor (VDR) expression is not a prognostic factor in breast cancer.

Breast cancer is characterized by its early haematogenous dissemination. Current modalities of risk assessment in lymph node-negative patients, to determine which patients should receive adjuvant chemotherapy, are not effective. The aim of this study was to analyze whether vitamin D receptor (VDR) status is a prognostic factor that may be of importance for the assessment of recurrence in breast cancer. VDR expression was analyzed immunohistochemically in breast cancer patients (n=228). No statistically significant correlations were found comparing VDR expression with histopathological data (tumor stage, lymph node status, grading, histological tumor type), with the expression of estrogen receptors (ER) or progesterone receptors (PR), with the proliferation marker Ki-67, with the tumor suppressor gene p53 or with the S-phase index. Our findings indicate that VDR protein expression is not a prognostic factor in breast cancer. The strong VDR immunoreactivity that we observed in breast cancer specimens supports the body of evidence that breast cancer may be a target for therapeutically applied vitamin D analogues.

A novel tumour associated leucine zipper protein targeting to sites of gene transcription and splicing.

We describe here the definition and characterization of antigen CT-8/HOM-TES-85 encoded by a previously unknown gene and identified by serological expression screening using antibodies from a seminoma patient. Intriguingly, the leucine zipper region of CT-8/HOM-TES-85 shows an atypical amphipathy with clusters of hydrophobic residues that is exclusively shared by the N-myc proto-oncogene. CT-8/HOM-TES-85 gene is tightly silenced in normal tissues except for testis. However, it is frequently activated in human neoplasms of different types including lung cancer, ovarian cancer, melanoma and glioma. Endogenous as well as heterogeneously expressed CT-8/HOM-TES-85 targets predominantly to the nucleus forming a distinctive speckled pattern of nuclear dots arranged in macromolecular structures. By co-localization studies these speckles were identified as loci of transcriptional activity and splicing, suggesting that CT-8/HOM-TES-85 may be involved in these processes. The aberrant expression of CT-8/HOM-TES-85 in human neoplasms might therefore be involved in cancer associated alterations of transcriptional or post-transcriptional processes and thus may disclose new mechanisms involved in the manifestation of the cancer phenotype.

Analysis of 25-hydroxyvitamin D3-1alpha-hydroxylase in cervical tissue.

UNLABELLED: 1,25(OH)2D3 suppresses proliferation and induces differentiation in various cell types, including epithelial cells. Recently, extrarenal activity of 1alpha-hydroxylase for 25(OH)D3 has been reported in various cell types including macrophages, keratinocytes and prostate and colon cancer cells. The aim of this study was to analyze the expression of 1alpha-hydroxylase for 25-hydroxyvitamin D3 in normal cervical samples and in cervical cancer, in order to investigate whether cervical tissue possesses the capacity to produce 1,25(OH)2D3 from 25(OH)D3, indicating that 1,25(OH)2D3 may be a locally produced hormone that controls proliferation in cervical tissue and that alterations in local production of 1,25(OH)2D3 may be involved in tumourigenesis of cervical cancer. MATERIALS AND METHODS: RNA was extracted from normal cervical tissue (n=4), cervical carcinomas (n=8) and HeLa cells using the method of Chomczynski. RNA was reverse-transcribed and RNA-levels were semiquantitatively detected by PCR. RESULTS: mRNA of 1alpha-hydroxylase for 25-hydroxyvitamin D3 was detected in more than 50% of samples analyzed in normal cervical tissue and in cervical cancer with no visible difference between either group. mRNA of 1alpha-hydroxylase for 25-hydroxyvitamin D3 was detected in HeLa cells as well. CONCLUSION: 25(OH)D3-1alpha-hydroxylase is expressed in normal cervical tissue, in cervical cancer and in HeLa cells. Thus, normal cervical and cervical cancer cells seem to be able to synthesize 1alpha, 25(OH)2D3 that may be of significant importance for the growth control in normal and malignant cervical tissue. Normal cervical tissue and cervical cancer cells may be new targets for cancer prevention or cancer treatment with precursors of biologically active vitamin D analogues.

Vitamin D receptor (VDR) expression is not a prognostic factor in cervical cancer.

BACKGROUND: The aim of this study was to analyze whether VDR status is a prognostic factor that may be of importance for the assessment of recurrence in cervical cancer. MATERIALS AND METHODS: VDR-, Ki-67- and p53-status were analyzed immunohistochemically in cervical cancer patients (n=50) and in benign cervical tissue (n=15). The histopathological data of the tumours were evaluated. RNA was extracted from normal cervical tissue (n=4) and cervical carcinomas (n=8) using the method of Chomczynski. RNA was reverse-transcribed and RNA-levels were semiquantitatively detected by PCR. RESULTS: The expression of VDR was significantly increased in cervical cancer compared to normal cervical tissue on the protein-level but not on the RNA-level. No statistically significant correlations were found comparing VDR status with histopathological data (tumour stage, lymph node status, grading, histological tumour type), with the expression of the proliferation marker Ki-67 and of the tumour suppressor gene p53. CONCLUSION: Our findings indicate that VDR protein expression is not a prognostic factor in cervical cancer. The strong I/DR immunoreactivity that we observed in cervical cancer specimens supports the body of evidence that cervical cancer may be a target for therapeutically applied vitamin D analogues.