The protective effect of p16INK4a in oral cavity carcinomas: p16Ink4A dampens tumor invasion—integrated analysis of expression and kinomics pathways

Abstract

A large body of evidence shows that p16 INK4a overexpression predicts improved survival and increased radiosensitivity in HPV-mediated oropharyngeal squamous cell carcinomas.(OPSCC). Here we demonstrate that the presence of transcriptionally active HPV16 in oral cavity squamous cell carcinomas does not correlate with p16 INK4a overexpression, enhanced local tumor immunity, or improved outcome. It is interesting that HPVmediated oropharyngeal squamous cell carcinomas can be categorized as having a 'nonaggressive' invasion phenotype, whereas aggressive invasion phenotypes are more common in HPV-negative squamous cell carcinomas. We have developed primary cancer cell lines from resections with known pattern of invasion as determined by our validated risk model. Given that cell lines derived from HPV-mediated oropharyngeal squamous cell carcinomas are less invasive than their HPV-negative counterparts, we tested the hypothesis that viral oncoproteins E6, E7, and p16 INK4a can affect tumor invasion. Here we demonstrate that p16 INK4a overexpression in two cancer cell lines (UAB-3 and UAB-4), derived from oral cavity squamous cell carcinomas with the most aggressive invasive phenotype (worst pattern of invasion type 5 (WPOI-5)), dramatically decreases tumor invasiveness by altering expression of extracellular matrix remodeling genes. Pathway analysis integrating changes in RNA expression and kinase activities reveals different potential p16 INK4a -sensitive pathways. Overexpressing p16 INK4a in UAB-3 increases EGFR activity and increases MMP1 and MMP3 expression, possibly through STAT3 activation. Overexpressing p16 INK4a in UAB-4 decreases PDGFR gene expression and reduces MMP1 and MMP3, possibly through STAT3 inactivation. Alternatively, ZAP70/Syk might increase MUC1 phosphorylation, leading to the observed decreased MMP1 expression.

p16 expression independent of human papillomavirus is associated with lower stage and longer disease-free survival in oral cavity squamous cell carcinoma

“…30 Dong et al 31 observed that homozygous p16 deletion was significantly more frequent in pT3 and pT4 tumours as compared to pT1 and pT2 tumours in their cohort of 30 cases of buccal SCC. Using OSCC derived cancer cell lines, Isayeva et al 5 demonstrated that p16 overexpression radically decreased tumour invasiveness by the reduction of matrix metalloproteinases (MMP-1 and MMP-9). MMPs are associated with bone invasion.…”

MARCKS phosphorylation is modulated by a peptide mimetic of MARCKS effector domain leading to increased radiation sensitivity in lung cancer cell lines

“…A total of 100 ng RNA was prepared in a 30 µl reaction volume and run on the automated nCounter system. Quality control and normalization were performed on the raw data using positive and negative control spots on the included GX Human Cancer Reference Panel chip and five housekeeping reference genes (16,17). …”

Biological Features of Human Papillomavirus-related Head and Neck Cancers Contributing to Improved Response

“…For instance, p16-positive oropharyngeal carcinomas also display a less locally invasive phenotype, which may account for improved outcomes. p16Ink4a overexpression in oral cavity tumour cell lines decreases tumour invasiveness by affecting extracellular matrix remodelling and expression of matrix metalloproteinases potentially accounting for the observation that p16-positive tumours are less locally invasive [56]. Additionally, in a cohort of primarily p16-positive oropharyngeal cancers that were surgically managed, nodal extracapsular extension, unless the node was completely obliterated, was not associated with poorer outcomes, as has been well established in HPV-negative HNSCC, suggesting a less locally aggressive phenotype in HPV-positive disease [57–59].…”