VALERIE H. CHEN

Transforming Growth Factor (TGF) Beta Receptor 2 and

Gastric Cancer

TGF Beta Pathway: TGF Beta Receptor 2 is a Ser/Thr Receptor Kinase

http://www.ncbi.nlm.nih.gov/books/bv.fcgi?rid=mboc4.figgrp.2875

Function of TGF Beta Pathway in Normal Cells

Pattern formation during embryonic development

Cell growth and proliferationCellular differentiationExtracellular matrix productionAngiogenesisTissue repairImmune regulationApoptosis

Example: Cell Growth Inhibition via TGF Beta Pathway

p21p27, p57Runx3

c-myccdc25

http://www.ncbi.nlm.nih.gov/books/bv.fcgi?rid=mboc4.figgrp.2875

Gastric Background

http://i.ehow.com/images/GlobalPhoto/Articles/4586983/77857_Full.jpg

http://www.auburn.edu/~bantawm/Notes/Digestion%20Notes_files/image010.jpg

Most (85%) cases of gastric cancer are adenocarcinomas that occur in the lining of the stomach (mucosa)

In 2008, there were ~21,500 new cases of gastric cancer and ~10,880 deaths

Unregulated DNA Synthesis in Gastric Cancer

Park et al., Proc Natl Acad Sci 1994 .

Abnormal TGF Beta Receptor 2 mRNA Transcripts and Protein Expression in Gastric

Cancer

FIG. 2. Northern blot analysis of TGF-beta receptor mRNA expression. Two micrograms of poly(A)+ RNA from cells treated with porcine TGF-beta 1 at 5 ng/ml (+) or a saline vehicle (-) for 48 hr were analyzed for the effect of TGF-beta on the expression of TGF-beta receptors. Hybridization with TGF-beta type II receptor cDNA shows various aberrant expression patterns of type II receptor mRNA. Type II receptor mRNA is absent or undetectable in SNU-1, -484, and -638, is increased in SNU-601 and -719, and is truncated (~1 kb) (thin arrow) in SNU-5 and -668 (in longer exposure). SNU-16, sensitive to growth inhibition by TGF-beta, expresses a full-size (~5.5 kb) type II receptor mRNA (thick arrow). Hybridization with rat glyceraldehyde phosphate dehydrogenase cDNA is show as control for mRNA loading.

Park et al., Proc Natl Acad Sci 1994 .

FIG. 4. TGF-beta type II receptor expression. Immunoprecipitation followed by immunoblot analysis of the whole cell lysates with anti-human TGF-beta type II receptor rabbit antibody shows that expression of the type II receptor corresponds with the expression of type II receptor mRNA. Note that expression of the type II receptor was not detectable in SNU-1 and -5 (lanes 1 and 2) and was overexpressed in SNU-719 (lane 4) compared to that of SNU-16 (lane 3).

TGF Beta Receptor 2 Undergoes Genetic Alterations in Gastric Cancer

Park et al., Proc Natl Acad Sci 1994 .

FIG. 4. TGF-beta type II receptor expression. Immunoprecipitation followed by immunoblot analysis of the whole cell lysates with anti-human TGF-beta type II receptor rabbit antibody shows that expression of the type II receptor corresponds with the expression of type II receptor mRNA. Note that expression of the type II receptor was not detectable in SNU-1 and -5 (lanes 1 and 2) and was overexpressed in SNU-719 (lane 4) compared to that of SNU-16 (lane 3).

Move from Correlation to Causation…

But, that’s all correlative data…

You’re right. Let’s look at cause-and-effect…

Transfection of Wild Type TGF Beta Receptor 2 Restores Expression

Chang et al., Cancer Research 1997.

Fig. 1. Expression of TGF-beta RII mRNA in SNU-638 cells infected with MFG-TGF-beta RII. A Northern blot analysis of TGF-beta RII mRNA in the MFG-TGF-beta RII and MFG-CAT-SNU-638 cell lines. Total RNA was isolated from the MFG-TGF-beta RII and MFG-CAT-SNU-638 human gastric cancer cell lines and analyzed by Northern analysis using 32P labeled TGF-beta RII and neomycin probes. A radiolabeled probe for 5SRNA was used to control for loading.

Transfection of Wild Type TGF Beta Receptor 2 Restores TGF Beta Sensitivity

Fig. 2. TGF-beta I sensitivity in wild-type TGF-beta RII-expressing SNU-638 cells. A. wild-type TGF-beta RII-expressing SNU-638 cells and CAT-expressing SNU-638 cells were treated with increasing doses of TGF-beta l (0-5 ng/ml), and [3H]thymidine incorporation was examined. B. changes in cell number in DMEM + 10% fetal bovine serum were examined as a function of time with 10 ng/ml TGF-beta 1 in SNU-638-CAT cells or SNU-638-RII cells.

Chang et al., Cancer Research 1997.

Fig. 3. Tumorigenicity of MFG-TGF-beta RII and MFG-CAT SNU-638 cells. Five X 106 cells each were injected s.c. into nude mice (n = 10). Tumor volume was followed for 5 weeks. In mice that were inoculated with TGF-beta RII-expressing SNU-638 cells, the tumor growth rate was reduced dramatically. Values are the means means±SE of established tumors.

Chang et al., Cancer Research 1997.

Transfection of Wild Type TGF Beta Receptor 2 Reduces Tumorigenicity

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