Downregulation of the α 1 - and β 1 -subunit of sGC in Arterial Smooth Muscle Cells of OPSCC Is HPV-Independent

NO binds to heme of the β 1 -subunit of sGC, activates the enzyme in the reduced heme iron state in vascular smooth muscle cells (VSMCs), and generates cGMP-inducing vasodilatation and suppression of VSMC proliferation. In the complex tumor milieu with higher levels of reactive oxygen species (ROS), sGC heme iron may become oxidized and insensitive to NO. To change sGC from an NO-insensitive to NO-sensitive state or NO-independent manner, protein expression of sGC in VSMC is required.

Whether sGCα 1 β 1 exists at the protein level in arterial VSMCs of oropharyngeal squamous cell carcinoma (OPSCC) is unknown. In addition, whether differences in the genetic profile between human papillomavirus (HPV)–positive and HPV-negative OPSCC contributes to the regulation of sGCα 1 β 1 is unclear. Therefore, we compared the effects of HPV-positive and HPV-negative OPSCC on the expression of sGCα 1 β 1 in arterial VSMCs from tumor-free and tumor-containing regions of human tissue sections using quantitative immunohistochemistry.