Cross-platform expression profiling demonstrates that SV40 small tumor antigen activates Notch, Hedgehog, and Wnt...

Area of Science:

• Molecular Biology
• Oncology
• Virology

Background:

• Previous analysis of human embryonic kidney (HEK) cell lines identified gene expression changes induced by simian virus 40 (SV40) small tumor antigen (ST) using Affymetrix GeneChips.
• Cross-validation and expansion of initial findings necessitated comparison using an alternative microarray platform.

Purpose of the Study:

• To compare gene expression profiles of HEK cell lines with and without SV40 ST expression using a different microarray platform.
• To validate and extend previous findings on SV40 ST-mediated gene expression alterations.

Main Methods:

• Analysis of matched HEK cell lines with and without SV40 ST expression.
• Utilized an Applied Biosystems (AB) microarray platform with single 60-mer oligonucleotides and single-color quantitative chemiluminescence detection.
• Confirmed gene expression changes using quantitative reverse transcription PCR (qRTPCR).

Main Results:

• The AB platform identified 1927 genes affected by SV40 ST, significantly more than the 456 identified by the Affymetrix platform.
• Technical replicates increased the total identified genes to 3478, confirming 61% of the original findings.
• qRTPCR confirmed 20 newly identified genes, including components of Wnt, Notch, and Hedgehog signaling pathways, indicating SV40 ST activation of developmental pathways.
• While Notch inhibitors had no effect on cell survival, cyclopamine demonstrated a potent killing effect on cells expressing SV40 ST.

Conclusions:

• SV40 ST expression significantly alters gene expression profiles compared to previous analyses.
• SV40 ST sensitizes cells to Hedgehog pathway inhibitors, suggesting a role in cell survival regulation.
• These findings highlight the potential of targeting the Hedgehog pathway in SV40-associated cancers.