Tumor Cell Extrinsic Synaptogyrin 3 Expression as a Diagnostic and Prognostic Biomarker in Head and Neck Cancer.

Over 70% of oropharyngeal head and neck squamous cell carcinoma (HNSC) cases in the United States are positive for human papillomavirus (HPV) yet biomarkers for stratifying oropharyngeal head and neck squamous cell carcinoma (HNSC) patient risk are limited. We used immunogenomics to identify differentially expressed genes in immune cells of HPV(+) and HPV(-) squamous carcinomas. Candidate genes were tested in clinical specimens using both quantitative RT-PCR and IHC and validated by IHC using the Carolina Head and Neck Cancer Study (CHANCE) tissue microarray of HNSC cases. We performed multiplex immunofluorescent staining to confirm expression within the immune cells of HPV(+) tumors, receiver operating characteristic (ROC) curve analyses, and assessed survival outcomes. The neuronal gene Synaptogyrin-3 (SYNGR3) is robustly expressed in immune cells of HPV(+) squamous cancers. Multiplex immunostaining and single cell RNA-seq analyses confirmed SYNGR3 expression in T cells, but also unexpectedly in B cells of HPV(+) tumors. ROC curve analyses revealed that combining SYNGR3 and p16 provides more sensitivity and specificity for HPV detection compared to p16 IHC alone. SYNGR3-high HNSC patients have significantly better prognosis with five-year OS and DSS rates of 60% and 71%, respectively. Moreover, combining p16 localization and SYNGR3 expression can further risk stratify HPV(+) patients such that high cytoplasmic, low nuclear p16 do significantly worse (Hazard Ratio, 8.6; P = 0.032) compared to patients with high cytoplasmic, high nuclear p16. SYNGR3 expression in T and B cells is associated with HPV status and enhanced survival outcomes of HNSC patients.

Activation of the CREB Coactivator CRTC2 by Aberrant Mitogen Signaling promotes oncogenic functions in HPV16 positive head and neck cancer.

Head and neck squamous cell carcinoma (HNSCC) is the 6th most common cancer worldwide and incidence rates are continuing to rise globally. Patients often present with locally advanced disease and a staggering 50% chance of relapse following treatment. Aberrant activation of adaptive response signaling pathways, such as the cAMP/PKA pathway, induce an array of genes associated with known cancer pathways that promote tumorigenesis and drug resistance. We identified the cAMP Regulated Transcription Coactivator 2 (CRTC2) to be overexpressed and constitutively activated in HNSCCs and this confers poor prognosis. CRTCs are regulated through their subcellular localization and we show that CRTC2 is exclusively nuclear in HPV(+) HNSCC, thus constitutively active, due to non-canonical Mitogen-Activated Kinase Kinase 1 (MEKK1)-mediated activation via a MEKK1-p38 signaling axis. Loss-of-function and pharmacologic inhibition experiments decreased CRTC2/CREB transcriptional activity by reducing nuclear CRTC2 via nuclear import inhibition and/or by eviction of CRTC2 from the nucleus. This shift in localization was associated with decreased proliferation, migration, and invasion. Our results suggest that small molecules that inhibit nuclear CRTC2 and p38 activity may provide therapeutic benefit to patients with HPV(+) HNSCC.

An Immunocompetent Mouse Model of HPV16(+) Head and Neck Squamous Cell Carcinoma.

The incidence of human papilloma virus (HPV)-associated head and neck squamous cell carcinoma (HNSCC) is increasing and implicated in more than 60% of all oropharyngeal carcinomas (OPSCCs). Although whole-genome, transcriptome, and proteome analyses have identified altered signaling pathways in HPV-induced HNSCCs, additional tools are needed to investigate the unique pathobiology of OPSCC. Herein, bioinformatics analyses of human HPV(+) HNSCCs revealed that all tumors express full-length E6 and identified molecular subtypes based on relative E6 and E7 expression levels. To recapitulate the levels, stoichiometric ratios, and anatomic location of E6/E7 expression, we generated a genetically engineered mouse model whereby balanced expression of E6/E7 is directed to the oropharyngeal epithelium. The addition of a mutant PIK3CAE545K allele leads to the rapid development of pre-malignant lesions marked by immune cell accumulation, and a subset of these lesions progress to OPSCC. This mouse provides a faithful immunocompetent model for testing treatments and investigating mechanisms of immunosuppression.

cAMP/CREB-regulated LINC00473 marks LKB1-inactivated lung cancer and mediates tumor growth.

The LKB1 tumor suppressor gene is frequently mutated and inactivated in non-small cell lung cancer (NSCLC). Loss of LKB1 promotes cancer progression and influences therapeutic responses in preclinical studies; however, specific targeted therapies for lung cancer with LKB1 inactivation are currently unavailable. Here, we have identified a long noncoding RNA (lncRNA) signature that is associated with the loss of LKB1 function. We discovered that LINC00473 is consistently the most highly induced gene in LKB1-inactivated human primary NSCLC samples and derived cell lines. Elevated LINC00473 expression correlated with poor prognosis, and sustained LINC00473 expression was required for the growth and survival of LKB1-inactivated NSCLC cells. Mechanistically, LINC00473 was induced by LKB1 inactivation and subsequent cyclic AMP-responsive element-binding protein (CREB)/CREB-regulated transcription coactivator (CRTC) activation. We determined that LINC00473 is a nuclear lncRNA and interacts with NONO, a component of the cAMP signaling pathway, thereby facilitating CRTC/CREB-mediated transcription. Collectively, our study demonstrates that LINC00473 expression potentially serves as a robust biomarker for tumor LKB1 functional status that can be integrated into clinical trials for patient selection and treatment evaluation, and implicates LINC00473 as a therapeutic target for LKB1-inactivated NSCLC.

Clinical potential of gene mutations in lung cancer.

Lung cancer is the most common cancer type worldwide and the leading cause of cancer related deaths in the United States. The majority of newly diagnosed patients present with late stage metastatic lung cancer that is inoperable and resistant to therapies. High-throughput genomic technologies have made the identification of genetic mutations that promote lung cancer progression possible. Identification of the mutations that drive lung cancer provided new targets for non-small cell lung cancer (NSCLC) treatment and led to the development of targeted therapies such as tyrosine kinase inhibitors that can be used to combat the molecular changes that promote cancer progression. Development of targeted therapies is not the only clinical benefit of gene analysis studies. Biomarkers identified from gene analysis can be used for early lung cancer detection, determine patient's prognosis and response to therapy, and monitor disease progression. Biomarkers can be used to identify the NSCLC patient population that would most benefit from treatment (targeted therapies or chemotherapies), providing clinicians tools that can be used to develop a personalized treatment plan. This review explores the clinical potential of NSCLC genetic studies on diagnosing and treating NSCLC.

RGS16, a novel p53 and pRb cross-talk candidate inhibits migration and invasion of pancreatic cancer cells.

Data collected since the discovery of p53 and pRb/RB1 suggests these tumor suppressors cooperate to inhibit tumor progression. Patients who have mutations in both p53 and RB1 genes have increased tumor reoccurrence and decreased survival compared to patients with only one tumor suppressor gene inactivated. It remains unclear how p53 and pRb cooperate toward inhibiting tumorigenesis. Using RNA expression profiling we identified 179 p53 and pRb cross-talk candidates in normal lung fibroblasts (WI38) cells exogenously coexpressing p53 and pRb. Regulator of G protein signaling 16 (RGS16) was among the p53 and pRb cross-talk candidates and has been implicated in inhibiting activation of several oncogenic pathways associated with proliferation, migration, and invasion of cancer cells. RGS16 has been found to be downregulated in pancreatic cancer patients with metastases compared to patients without metastasis. Expression of RGS16 mRNA was decreased in the pancreatic cancer cell lines tested compared to control. Expression of RGS16 inhibited migration of the BxPC-3 and AsPC-1 but not PANC-1 cells and inhibited invasion of BxPC-3 and AsPC-1 cells with no impact on cell viability. We have identified for the first time p53 and pRb cross-talk candidates and a role for RGS16 to inhibit pancreatic cancer migration and invasion.