Abstract 3712: The relationship of Procollagen alpha 1 type 1 (Col1A1) / DDR2 signaling in malignant glioma and sensitivity to STAT 3/5 inhibitor
Authors: Chen Shumei , Wu Chunjing , Li Ying-Ying , Wangpaichitr Medhi , Benveniste Ronald J. , Turkson James , Savaraj Niramol , Feun Lynn G. 
Published: July 2016

Abstract
We have previously shown that Procollagen alpha 1 type 1 (Col1A1) is found in low and intermediate grade glioma and in less aggressive glioblastoma multiforme (GBM) (Cancer Invest. 23:577, 2005). However, these tumor cells are more prone to ER stress -inducing agents such as Befeldine (BFA) which block the transport of Procollagen to the cell surface. We also found that GBM cells which possess Col1A1 also express DDR2. The role of Col1A1/ DDR2 signaling in glioma is not known. We have used three GBM cell lines: Glioma1 established in our laboratory from a patient who progressed from grade 3 to grade 4, U-118, A-172 and U-373 to study this signaling pathway. Both Glioma1 and U-118 express Col1A1 and DDR1 and 2. A-172 and U-373 do not express Col1A1 but express both DDR2. U-373 does not express HSP47 which is an essential protein to fold collagen. In order to define the function of DDR2/ Col1A1 in GBM, we have used knock down COL1A1 and DDR2. Silencing Col1A1 leads to a significant increase in invasiveness by Matrigel assay which indicated that Col1A1 is important in preventing invasion in GBM and hence is found more in low and intermediate grade glioma. However, it has minimal effect on cell cycle or cell proliferation. Next, we have silenced DDR2 in all 4 cell lines and studied the biochemical changes. We found that silencing DDR2 does not affect cell proliferation, cell death or cell cycle. However, it does affect the sensitivity to BFA. In cell lines which possess Col1A1, the cell viability increased by 20 -30% (p &lt;0.05). In contrast, cell lines which do not express Col1A1, the cell viability decreased by 25-30% (p&lt;0.01). However, there is no difference in sensitivity to the DNA damaging agent cisplatin. Thus, DDR2 may function differently depending on the presence of Col1A1. To explore this further, we have performed a limited phoshoprotein kinase array in Glioma 1 with siCol1A1 or siDDR2. We found increase in STAT3, 5 and STAT6 upon silencing either Col1A1 or DDR2 which is further confirmed by immunoblot in Glioma 1 for pSTAT 3 and 5. We then tested the antitumor effect of STAT3/5 inhibitor (SH4-54) a benzoic acid based inhibitor (provided by Dr. James Turkson) which interferes with the SH2 and DNA binding domains as well as tyr705 phosphorylation in Glioma1 and U-118 w/wo SiCol1A1. At 0.5 uM the cell viability in Glioma 1 is 55.65 + 1.35 and 74.2 + 4.6 in U-118 while SiCol1A1 it decreased to 44.5 + 3.53% in Glioma 1 and 58.2+ 1.9, respectively, with minimal activity in A-172 which does not possess Col1A1. In contrast, there is no effect with another commercially available STAT 3 inhibitor S31-201 which only interferes with DNA binding domain. Overall, our data suggest that Col1A1/DDR2/ STAT signaling may be important in certain GBM cell lines and can be exploited for future treatment in brain tumor (Supported by Wanfang Hospital-Taipei Medical University Fellowship and VA Research Fund).
Citation Format: Shumei Chen, Chunjing Wu, Ying-Ying Li, Medhi Wangpaichitr, Ronald J. Benveniste, James Turkson, Niramol Savaraj, Lynn G. Feun. The relationship of Procollagen alpha 1 type 1 (Col1A1) / DDR2 signaling in malignant glioma and sensitivity to STAT 3/5 inhibitor. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 3712.