Abstract
Receptor crosstalk is an emerging and recurrent theme in cytokine and growth factor signaling; however, insight into the mechanism(s) underlying these interactions remains limited. Recently, we reported that crosstalk occurs between ErbB3 and the interferon alpha (IFN-α) signaling complex in the myeloma cell line KAS-6/1 and that this crosstalk contributes to the regulation of cell proliferation. In this study, we examined the mechanism underlying the transactivation of ErbB3 in the IFN-α growth-responsive KAS-6/1 cells. The examination of IFN-α receptor 1 and 2 (IFNAR1 and IFNAR2) levels revealed that the KAS-6/1 cell line overexpresses IFNAR1 relative to other myeloma cell lines that are growth arrested by IFN-α. Subsequent investigation of Tyk2, which is constitutively associated with IFNAR1, demonstrated that Tyk2 activation is uniquely sustained in the KAS-6/1 cell line following IFN-α stimulation. Interestingly, silencing of Tyk2 expression via siRNA resulted in attenuation of ErbB3 transactivation. However, inhibition of Jak1 expression also decreased IFN-α-induced tyrosine phosphorylation of ErbB3. Finally, siRNA downregulation of Tyk2 and Jak1 was found to decrease IFN-α-stimulated proliferation. These findings validate our previous report of ErbB3 involvement in IFN-α-induced proliferation and further suggest that both Janus kinase members, Tyk2 and Jak1, play a role in the transactivation of ErbB3 in this model system.
Original language | English (US) |
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Pages (from-to) | 1197-1205 |
Number of pages | 9 |
Journal | Oncogene |
Volume | 23 |
Issue number | 6 |
DOIs | |
State | Published - Feb 12 2004 |
Keywords
- ErbB3
- Interferon-alpha
- Jak1
- Multiple myeloma
- Tyk2
ASJC Scopus subject areas
- Molecular Biology
- Genetics
- Cancer Research