Related Experiment Videos
Expression of transforming growth factor beta1 and its type II receptor in mouse colon tumors induced by azoxymethane
Q S Wang1, K Guda, A Papanikolaou
1BioGenex Laboratories, San Ramon, CA 94583, USA.
Abstract:
Alterations in transforming growth factor beta1 (TGF-beta1) and its type II receptor (TbetaR-II) have been implicated in the pathogenesis of a variety of human cancers and animal tumor models. We postulated that TGF-beta1 and TbetaR-II alterations may also be involved in mouse colon tumorigenesis induced by the chemical carcinogen, azoxymethane (AOM). In the present study, normal colon tissues and AOM-induced colon tumors from SWR/J mice were analyzed for mutational changes in the TbetaR-II gene, and the expression and localization of TGF-beta1 and TbetaR-II were examined by reverse transcription-polymerase chain reaction (RT-PCR) and immunohistochemisty. Direct DNA sequencing of the coding sequence of the TbetaR-II gene revealed no mutational changes in tumors induced by AOM when compared with the sequence from normal colon tissue. However, TGF-beta1 and TbetaR-II mRNA levels in tumor samples were increased 1.8-fold (p<0.01) and 1.3-fold (p<0.01), respectively, when compared with control mouse colon tissue. The results of immunohistochemical analysis of TGF-beta1 and TbetaR-II were correlated with mRNA expression data. An increase in staining intensity of both TGF-beta and TbetaR-II were observed in colon tumors. These findings suggest that alterations in the expression of TGF-beta1 and TbetaR-II may be involved in the pathogenesis of colon tumors induced by AOM in mice.
Insights
This study found that while the TbetaR-II gene had no mutations, the expression of TGF-beta1 and its receptor TbetaR-II increased in mouse colon tumors. These expression changes may drive cancer development.
Area of Science:
- Oncology
- Molecular Biology
- Carcinogenesis
Background:
- Transforming growth factor beta1 (TGF-beta1) and its type II receptor (TbetaR-II) are linked to various cancers.
- The role of TGF-beta1 and TbetaR-II in azoxymethane (AOM)-induced mouse colon tumorigenesis is not fully understood.
Purpose of the Study:
- To investigate potential alterations in the TbetaR-II gene and the expression of TGF-beta1 and TbetaR-II in AOM-induced mouse colon tumors.
- To determine if these factors are involved in the pathogenesis of chemically induced colon cancer in mice.
Main Methods:
- Analysis of TbetaR-II gene mutations in normal and tumor colon tissues using DNA sequencing.
- Examination of TGF-beta1 and TbetaR-II mRNA expression via reverse transcription-polymerase chain reaction (RT-PCR).
- Immunohistochemistry was used to assess the protein localization and expression levels of TGF-beta1 and TbetaR-II.
Main Results:
- No mutational changes were detected in the TbetaR-II gene of AOM-induced colon tumors compared to normal tissue.
- A significant increase in TGF-beta1 mRNA (1.8-fold) and TbetaR-II mRNA (1.3-fold) was observed in tumor samples.
- Immunohistochemistry confirmed elevated protein levels and staining intensity for both TGF-beta1 and TbetaR-II in colon tumors, correlating with mRNA data.
Conclusions:
- Alterations in TGF-beta1 and TbetaR-II expression, rather than gene mutations, appear to play a role in AOM-induced mouse colon tumorigenesis.
- Increased expression of TGF-beta1 and TbetaR-II may contribute to the development of colon tumors in this model.
- Further research into the TGF-beta signaling pathway is warranted for understanding and potentially targeting colon cancer development.