Limits...
HIF1alpha isoforms in benign and malignant prostate tissue and their correlation to neuroendocrine differentiation.

Monsef N, Soller M, Panagopoulos I, Abrahamsson PA - BMC Cancer (2010)

Bottom Line: HIF1alpha and HIF1beta are two subunits of HIF1, a transcription factor important for angiogenesis.The aim of this study was to elucidate whether the cytoplasmic stabilization of HIF1alpha in androgen independent NE differentiated prostate cancer is due to the presence of certain HIF1alpha isoforms.Co-localization of this isoform with HIF1beta indicates that the HIF1alpha1.2 isoform might sequester HIF1beta in the cytoplasm.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Laboratory Medicine, Division of Pathology, Lund University Hospital, Sweden. Nastaran.Monsef@gmail.com

ABSTRACT

Background: Neuroendocrine (NE) differentiation in prostate cancer has been correlated with a poor prognosis and hormone refractory disease. In a previous report, we demonstrated the presence of immunoreactive cytoplasmic hypoxia inducible factor 1alpha (HIF1alpha), in both benign and malignant NE prostate cells. HIF1alpha and HIF1beta are two subunits of HIF1, a transcription factor important for angiogenesis. The aim of this study was to elucidate whether the cytoplasmic stabilization of HIF1alpha in androgen independent NE differentiated prostate cancer is due to the presence of certain HIF1alpha isoforms.

Methods: We studied the HIF1alpha isoforms present in 8 cases of benign prostate hyperplasia (BPH) and 43 cases of prostate cancer with and without NE differentiation using RT-PCR, sequencing analysis, immunohistochemistry and in situ hybridization.

Results: We identified multiple isoforms in both benign and malignant prostate tissues. One of these isoforms, HIF1alpha1.2, which was previously reported to be testis specific, was found in 86% of NE-differentiated prostate tumors, 92% of HIF1alpha immunoreactive prostate tumors and 100% of cases of benign prostate hyperplasia. Immunohistochemistry and in situ hybridization results showed that this isoform corresponds to the cytoplasmic HIF1alpha present in androgen-independent NE cells of benign and malignant prostate tissue and co-localizes with immunoreactive cytoplasmic HIF1beta.

Conclusion: Our results indicate that the cytoplasmic stabilization of HIF1alpha in NE-differentiated cells in benign and malignant prostate tissue is due to presence of an HIF1alpha isoform, HIF1alpha1.2. Co-localization of this isoform with HIF1beta indicates that the HIF1alpha1.2 isoform might sequester HIF1beta in the cytoplasm.

Show MeSH

Related in: MedlinePlus

RT-PCR analysis of HIF1α mRNA isoforms in benign prostate hyperplasia (B, Fig. 1a-f), NE differentiated prostate cancer (M1, Fig.1a-f)) and non NE differentiated prostate cancer (M2, Fig. 1a-f)). K (Fig. 1a-f) and T (Fig. 1b) correspond to control and testis tissue, respectively. HIF1α isoforms in LNCaP cells (Fig. 1g), Lane 1 represents HIF1α1.1, lane 2 represents HIF1α1.2, and lane 3 represents HIF1α1.3. Lane 4: bands detected with primers sets located in exons 10 and 13, lane 5 includes bands from primers located in exon 12 and lane 6 corresponds to bands detected with primers located in exons 13 and 15
© Copyright Policy - open-access
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC2913964&req=5

Figure 1: RT-PCR analysis of HIF1α mRNA isoforms in benign prostate hyperplasia (B, Fig. 1a-f), NE differentiated prostate cancer (M1, Fig.1a-f)) and non NE differentiated prostate cancer (M2, Fig. 1a-f)). K (Fig. 1a-f) and T (Fig. 1b) correspond to control and testis tissue, respectively. HIF1α isoforms in LNCaP cells (Fig. 1g), Lane 1 represents HIF1α1.1, lane 2 represents HIF1α1.2, and lane 3 represents HIF1α1.3. Lane 4: bands detected with primers sets located in exons 10 and 13, lane 5 includes bands from primers located in exon 12 and lane 6 corresponds to bands detected with primers located in exons 13 and 15

Mentions: HIF1α1.1 isoform was present in both benign and malignant prostate tissues (Table 4, Fig.1a). HIF1α1.2 was detected in 25 out of 43 cases of prostate cancer and in all cases of benign prostate hyperplasia (Table 4, Fig.1b). This isoform was expressed variably, although the signals from benign prostate tissues were very weak (Fig. 1b). We also found a correlation between this isoform and NE differentiation in prostate tumors. Eighty sex percent of prostate tumors with NE (compared to 28% of prostate tumors without NE) expressed this isoform (Table 4). Comparing the presence of this isoform with HIF1α immunostaining showed that 92% of cases with this isoform also showed HIF1α immunostaining (Table 4). Therefore, we suspect that the HIF1α1.2 isoform represents the cytoplasmic HIF1α in NE cells. The weak signals from benign prostate tissue can be explained by the fact that NE cells are rare in benign prostate tissue, making up only about 10% of the cells in the prostate gland. In addition, we used non-NE-differentiated LNCaP cells as a control, and these cells did not express this isoform, further indicating that it represents cytoplasmic HIF1α (Fig. 1g, lane 2).


HIF1alpha isoforms in benign and malignant prostate tissue and their correlation to neuroendocrine differentiation.

Monsef N, Soller M, Panagopoulos I, Abrahamsson PA - BMC Cancer (2010)

RT-PCR analysis of HIF1α mRNA isoforms in benign prostate hyperplasia (B, Fig. 1a-f), NE differentiated prostate cancer (M1, Fig.1a-f)) and non NE differentiated prostate cancer (M2, Fig. 1a-f)). K (Fig. 1a-f) and T (Fig. 1b) correspond to control and testis tissue, respectively. HIF1α isoforms in LNCaP cells (Fig. 1g), Lane 1 represents HIF1α1.1, lane 2 represents HIF1α1.2, and lane 3 represents HIF1α1.3. Lane 4: bands detected with primers sets located in exons 10 and 13, lane 5 includes bands from primers located in exon 12 and lane 6 corresponds to bands detected with primers located in exons 13 and 15
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC2913964&req=5

Figure 1: RT-PCR analysis of HIF1α mRNA isoforms in benign prostate hyperplasia (B, Fig. 1a-f), NE differentiated prostate cancer (M1, Fig.1a-f)) and non NE differentiated prostate cancer (M2, Fig. 1a-f)). K (Fig. 1a-f) and T (Fig. 1b) correspond to control and testis tissue, respectively. HIF1α isoforms in LNCaP cells (Fig. 1g), Lane 1 represents HIF1α1.1, lane 2 represents HIF1α1.2, and lane 3 represents HIF1α1.3. Lane 4: bands detected with primers sets located in exons 10 and 13, lane 5 includes bands from primers located in exon 12 and lane 6 corresponds to bands detected with primers located in exons 13 and 15
Mentions: HIF1α1.1 isoform was present in both benign and malignant prostate tissues (Table 4, Fig.1a). HIF1α1.2 was detected in 25 out of 43 cases of prostate cancer and in all cases of benign prostate hyperplasia (Table 4, Fig.1b). This isoform was expressed variably, although the signals from benign prostate tissues were very weak (Fig. 1b). We also found a correlation between this isoform and NE differentiation in prostate tumors. Eighty sex percent of prostate tumors with NE (compared to 28% of prostate tumors without NE) expressed this isoform (Table 4). Comparing the presence of this isoform with HIF1α immunostaining showed that 92% of cases with this isoform also showed HIF1α immunostaining (Table 4). Therefore, we suspect that the HIF1α1.2 isoform represents the cytoplasmic HIF1α in NE cells. The weak signals from benign prostate tissue can be explained by the fact that NE cells are rare in benign prostate tissue, making up only about 10% of the cells in the prostate gland. In addition, we used non-NE-differentiated LNCaP cells as a control, and these cells did not express this isoform, further indicating that it represents cytoplasmic HIF1α (Fig. 1g, lane 2).

Bottom Line: HIF1alpha and HIF1beta are two subunits of HIF1, a transcription factor important for angiogenesis.The aim of this study was to elucidate whether the cytoplasmic stabilization of HIF1alpha in androgen independent NE differentiated prostate cancer is due to the presence of certain HIF1alpha isoforms.Co-localization of this isoform with HIF1beta indicates that the HIF1alpha1.2 isoform might sequester HIF1beta in the cytoplasm.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Laboratory Medicine, Division of Pathology, Lund University Hospital, Sweden. Nastaran.Monsef@gmail.com

ABSTRACT

Background: Neuroendocrine (NE) differentiation in prostate cancer has been correlated with a poor prognosis and hormone refractory disease. In a previous report, we demonstrated the presence of immunoreactive cytoplasmic hypoxia inducible factor 1alpha (HIF1alpha), in both benign and malignant NE prostate cells. HIF1alpha and HIF1beta are two subunits of HIF1, a transcription factor important for angiogenesis. The aim of this study was to elucidate whether the cytoplasmic stabilization of HIF1alpha in androgen independent NE differentiated prostate cancer is due to the presence of certain HIF1alpha isoforms.

Methods: We studied the HIF1alpha isoforms present in 8 cases of benign prostate hyperplasia (BPH) and 43 cases of prostate cancer with and without NE differentiation using RT-PCR, sequencing analysis, immunohistochemistry and in situ hybridization.

Results: We identified multiple isoforms in both benign and malignant prostate tissues. One of these isoforms, HIF1alpha1.2, which was previously reported to be testis specific, was found in 86% of NE-differentiated prostate tumors, 92% of HIF1alpha immunoreactive prostate tumors and 100% of cases of benign prostate hyperplasia. Immunohistochemistry and in situ hybridization results showed that this isoform corresponds to the cytoplasmic HIF1alpha present in androgen-independent NE cells of benign and malignant prostate tissue and co-localizes with immunoreactive cytoplasmic HIF1beta.

Conclusion: Our results indicate that the cytoplasmic stabilization of HIF1alpha in NE-differentiated cells in benign and malignant prostate tissue is due to presence of an HIF1alpha isoform, HIF1alpha1.2. Co-localization of this isoform with HIF1beta indicates that the HIF1alpha1.2 isoform might sequester HIF1beta in the cytoplasm.

Show MeSH
Related in: MedlinePlus