Guha, Sushovan

Pancreatectomy is associated with significant morbidity and unpredictable outcome, with few diagnostic tools to determine, which patients gain the most benefit from this treatment, especially before the operation. This study aimed to define a preoperative signature panel of serum markers to indicate response to pancreatectomy for pancreatic cancer. Over 1000 patients with pancreatic cancer treated at two independent high‐volume institutions were included in this study and were divided into three groups, including resected, locally advanced and metastatic. Eight serum tumor markers most commonly used in gastrointestinal cancers were analyzed for patient outcome. Preoperative CA19‐9 independently indicated surgical response in pancreatic cancer. Patients with CA19‐9 ≥1000 U/mL generally had a poor surgical benefit. However, a subset of these patients still achieved a survival advantage when CA19‐9 levels decreased postoperatively. CEA and CA125 in the presence of CA19‐9 ≥1000 U/mL could independently predict the non‐decrease of CA19‐9 postoperatively. The combination of the three markers was useful for predicting a worse surgical outcome with a median survival of 5.1 months vs. 23.0 months (p < 0.001) for the training cohort and 7.0 months vs. 18.2 months (p < 0.001) for the validation cohort and also suggested a higher prevalence of early distant metastasis after surgery. Resected patients with this proposed signature showed no survival advantage over patients in the locally advanced group who did not receive pancreatectomy. Therefore, a preoperative serum signature of CEA+/CA125+/CA19‐9 ≥1000 U/mL is associated with poor surgical outcome and can be used to select appropriate patients with pancreatic cancer for pancreatectomy.

Abstract Background: Neutrophil gelatinase-associated lipocalin (NGAL), a member of lipocalin family, is a 25-kDa secreted glycoprotein. NGAL modulates multiple biological functions including cell proliferation, invasion, and metastasis. NGAL is upregulated in multiple gastrointestinal cancers including colorectal, pancreatic, and esophageal adenocarcinoma (EAC). Our group recently showed that NGAL over-expression significantly blocked metastasis of pancreatic adenocarcinoma cells [Cancer Research 68(15): 6100-6108, 2008]. However, the biological role of NGAL in EAC is not known. Aim: To examine the biological role of NGAL in human EAC cells both in vitro and in vivo. Methods and Results: We used OE33 (well-differentiated) and Flo-1 (poorly differentiated) EAC cell lines as our model system. We observed that OE33 cells have significantly higher levels of NGAL expression than Flo-1 cells both by qPCR and western blot analyses. To further study the biological role of NGAL in EAC, we created stable NGAL over-expression clones in Flo-1 (Flo1-NGAL) and NGAL under-expression clones in OE33 (OE33-shNGAL) using lentiviral system. We observed that under-expression of NGAL in OE33 significantly increased cell proliferation as determined by clonogenic assays. In contrast, NGAL over-expression in Flo-1 significantly suppressed cell proliferation. We also observed that NGAL under-expression increased cyclin D1 expression, a known cell cycle regulator. This, in part, explained increased EAC cell proliferation secondary to NGAL under-expression. In addition, NGAL over-expression potently suppressed and conversely, NGAL under-expression significantly increased invasion of EAC clones through MatrigelTM in vitro. Furthermore, to confirm our in vitro findings, we observed that OE33-shNGAL clones strikingly increased tumor volume in a subcutaneouos heterotopic xenograft model in nude mice. Conclusion: We demonstrated for the first time that NGAL under-expression increased cell proliferation and invasion in vitro, which could be in part secondary to regulation of cyclin D1 expression. NGAL under-expression also enhanced tumor growth in vivo. Thus, modulation of NGAL can be a novel therapeutic target in progression of EAC. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 3074.

Abstract Barrett's esophagus, a columnar metaplasia of the lower esophagus epithelium related to gastroesophageal reflux disease, is the strongest known risk factor for the development of esophageal adenocarcinoma (EAC). Understanding the signal transduction events involved in esophageal epithelium carcinogenesis may provide insights into the origins of EAC and may suggest new therapies. To elucidate the molecular pathways of bile acid–induced tumorigenesis, the newly identified inflammation-associated signaling pathway involving IκB kinases β (IKKβ), tuberous sclerosis complex 1 (TSC1), and mammalian target of rapamycin (mTOR) downstream effector S6 kinase (S6K1) was confirmed to be activated in immortalized Barrett's CPC-A and CPC-C cells and esophageal cancer SEG-1 and BE3 cells. Phosphorylation of TSC1 and S6K1 was induced in response to bile acid stimulation. Treatment of these cells with the mTOR inhibitor rapamycin or the IKKβ inhibitor Bay 11-7082 suppressed bile acid–induced cell proliferation and anchorage-independent growth. We next used an orthotopic rat model to evaluate the role of bile acid in the progression of Barrett's esophagus to EAC. Of interest, we found high expression of phosphorylated IKKβ (pIKKβ) and phosphorylated S6K1 (pS6K1) in tumor tissues and the Barrett's epithelium compared with normal epithelium. Furthermore, immunostaining of clinical EAC tissue specimens revealed that pIKKβ expression was strongly correlated with pS6K1 level. Together, these results show that bile acid can deregulate TSC1/mTOR through IKKβ signaling, which may play a critical role in EAC progression. In addition, Bay 11-7082 and rapamycin may potentially be chemopreventive drugs against Barrett's esophagus–associated EAC. [Cancer Res 2008;68(8):2632–40]