Oncogenic GNAS drives a gastric pylorus program in intraductal papillary mucinous neoplasms of the pancreas.

OBJECTIVE: Intraductal Papillary Mucinous Neoplasms (IPMNs) are cystic lesions and bona fide precursors for pancreatic ductal adenocarcinoma (PDAC). Recently, we showed that acinar to ductal metaplasia, an injury repair program, is characterized by a transcriptomic program similar to gastric spasmolytic polypeptide expressing metaplasia (SPEM), suggesting common mechanisms of reprogramming between the stomach and pancreas. The aims of this study were to assay IPMN for pyloric markers and to identify molecular drivers of this program. DESIGN: We analyzed RNA-seq studies of IPMN for pyloric markers, which were validated by immunostaining in patient samples. Cell lines expressing Kras G12D +/- GNAS R201C were manipulated to identify distinct and overlapping transcriptomic programs driven by each oncogene. A PyScenic-based regulon analysis was performed to identify molecular drivers in the pancreas. Expression of candidate drivers was evaluated by RNA-seq and immunostaining. RESULTS: Pyloric markers were identified in human IPMN. GNAS R201C drove expression of these markers in cell lines and siRNA targeting of GNAS R201C or Kras G12D demonstrates that GNAS R201C amplifies a mucinous, pyloric phenotype. Regulon analysis identified a role for transcription factors SPDEF, CREB3L1, and CREB3L4, which are expressed in patient samples. siRNA-targeting of Spdef inhibited mucin production. CONCLUSION: De novo expression of a SPEM phenotype has been identified in pancreatitis and a pyloric phenotype in Kras G12D -driven PanIN and Kras G12D ;GNAS R201C -driven IPMN, suggesting common mechanisms of reprogramming between these lesions and the stomach. A transition from a SPEM to pyloric phenotype may reflect disease progression and/or oncogenic mutation. IPMN-specific GNAS R201C amplifies a mucinous phenotype, in part, through SPDEF.

Loss of the α2ß1 integrin alters human papilloma virus-induced squamous carcinoma progression in vivo and in vitro.

Expression of the α2ß1 integrin, a receptor for collagens and laminin, is altered during tumor progression. Recent studies have linked polymorphisms in the α2 integrin gene with oral, squamous cell carcinoma (SCC). To determine the α2ß1 integrin's role in SCC progression, we crossed α2-null mice with K14-HPV16 transgenic animals. Pathological progression to invasive carcinoma was evaluated in HPV-positive, α2-null (HPV/KO) and HPV-positive, wild-type (HPV/WT) animals. α2ß1 integrin expression stimulated progression from hyperplasia and papillomatosis to dysplasia with concomitant dermal mast cell infiltration. Moreover, lymph node metastasis was decreased by 31.3% in HPV/KO, compared to HPV/WT, animals. To evaluate the integrin-specific impact on the malignant epithelium versus the microenvironment, we developed primary tumor cell lines. Although transition from dysplasia to carcinoma was unaltered during spontaneous tumor development, isolated primary HPV/KO SCC cell lines demonstrated decreased migration and invasion, compared to HPV/WT cells. When HPV/WT and HPV/KO SCC cells were orthotopically injected into WT or KO hosts, tumor α2ß1 integrin expression resulted in decreased tumor latency, regardless of host integrin status. HPV/WT SCC lines failed to demonstrate a proliferative advantage in vitro, however, the HPV/WT tumors demonstrated increased growth compared to HPV/KO SCC lines in vivo. Although contributions of the integrin to the microenvironment cannot be excluded, our studies indicate that α2ß1 integrin expression by HPV-transformed keratinocytes modulates SCC growth and progression.

Sonographic quantification of ovarian tumor vascularity.

OBJECTIVE: The purpose of this study was to assess the diagnostic accuracy of quantitated color Doppler sonography in differentiating benign from malignant ovarian tumors, with the use of tumor histologic examination as a reference standard. METHODS: The vascularity of 38 ovarian masses (30 benign and 8 malignant) as quantitatively depicted with color Doppler sonography was analyzed with a readily available software program (ImageJ; National Institutes of Health, Bethesda, MD). The following quantitative sonographic criteria for tumor vascularity were analyzed: the vascularity index (VI) quantified the difference between the total number of pixels and the number of pixels containing no color/totalx100, whereas the power-weighted pixel density (PWPD) weighted the strength of the signal/total. The accuracy of sonographic criteria for malignant ovarian tumors was evaluated with univariate analysis. Results of tumor histologic examination were used as proof of the final diagnosis. RESULTS: The mean values of VI and PWPD were significantly different in benign versus malignant ovarian lesions (VI, 1.3+/-1.6 versus 4.7+/-3.9; P<.01; PWPD, 2338+/-3305 versus 9403+/-9946; P<.05). With a VI of greater than 2.3, sensitivity of 75% and specificity of 90% were obtained. When combined with a PWPD of greater than 4555, sensitivity improved to 88%, and specificity improved to 93%. Morphologic analysis had sensitivity of 72% and specificity of 76% for malignancies. CONCLUSIONS: Quantitated color Doppler sonography was found to be helpful for distinguishing benign from malignant ovarian masses. However, the wide range in values makes it most useful as an adjunct to morphologic assessment. It is anticipated that quantitated color Doppler sonography could result in a slight improvement in detection of ovarian malignancies.

Expansion of myeloid immune suppressor Gr+CD11b+ cells in tumor-bearing host directly promotes tumor angiogenesis.

We demonstrate a novel tumor-promoting role of myeloid immune suppressor Gr+CD11b+ cells, which are evident in cancer patients and tumor-bearing animals. These cells constitute approximately 5% of total cells in tumors. Tumors coinjected with Gr+CD11b+ cells exhibited increased vascular density, vascular maturation, and decreased necrosis. These immune cells produce high levels of MMP9. Deletion of MMP9 in these cells completely abolishes their tumor-promoting ability. Gr+CD11b+ cells were also found to directly incorporate into tumor endothelium. Consistent with this observation, Gr+CD11b+ cells acquire endothelial cell (EC) properties in tumor microenvironment and proangiogenic culture conditions. Our data provide evidence that Gr+CD11b+ cells of immune origin induced by tumors directly contribute to tumor growth and vascularization by producing MMP9 and differentiating into ECs.