Self-expandable metal stents (SEMSs) are frequently utilized for palliation of malignant gastric and/or duodenal outlet obstruction (GDOO). Re-establishing luminal patency with accurate SEMS positioning while limiting migration and adjacent tissue injury is an important technical consideration and aim. The duodenal HANAROSTENT^® was introduced in the USA in 2019 and developed with these challenges in mind. As the first center in the USA to deploy the duo-denal HANAROSTENT^® in clinical practice, we herein examine our early experience with its use. Specifically, we describe 7 consecutive cases of malignant GDOO in which a duodenal HANAROSTENT^® was placed for on-label use, defined as palliative treatment of malignant gastric and/or duodenal obstruction. All stents were 22 mm in diameter, with 5 being 90 mm and 2 being 120 mm in length. Technical and clinical success with duodenal HANAROSTENT^® placement were achieved in all 7 cases (100%). In no case was stent adjustment required post-deployment. There were no stent-related adverse events, and no subsequent endoscopic procedures were necessary in any of the patients during a mean follow-up of 5 months (range 1-12 months). In summary, the duodenal HANAROSTENT^® appears to perform well and be a promising alternative to other available duodenal SEMSs. As experience in the USA with this newly introduced duodenal SEMS grows, multicenter prospective data should be collected to better establish its relative safety and efficacy.

Purpose

Expression of CBL, an ubiquitin ligase, is decreased in 60% of human pancreatic ductal adenocarcinomas (PDAC) and is associated with shorter overall survival. We sought to determine how low CBL directly contributes to clinically more aggressive PDAC.

Experimental design

Human PDACs were stained for CBL, pEGFR, and EGFR. CBL-low was modeled in PDAC cells (Panc-1, L3.6pl, and AsPC-1) via transient transfection (siRNA) or stable knockdown (shRNA). Cell viability and apoptosis were measured by MTT assays and FACS. Immunoblot and a phospho-receptor tyrosine kinase (pRTK) array were used to probe signal transduction. NOD-scid-IL2Rγ(null) mice were subcutaneously implanted with PDAC or PDAC(CBL-low) cells on opposite flanks and treated with gemcitabine ± erlotinib for ≥4 weeks.

Results

There was an inverse correlation between CBL and pEGFR protein expression in 12 of 15 tumors. CBL knockdown increased PDAC resistance to gemcitabine and 5-fluorouracil (5-FU) by upregulating pEGFR (Y1068), pERK, and pAKT. A pRTK array of PDAC(CBL-low) cells revealed additional activated tyrosine kinases but all to a much lower magnitude than EGFR. Increased chemoresistance from low CBL was abrogated by the EGFR inhibitor erlotinib both in vitro and in vivo. Erlotinib+gemcitabine-treated PDAC(CBL-low) cells exhibited greater apoptosis by cleaved PARP, caspase-3, and Annexin V/PI.

Conclusions

Low CBL causes chemoresistance in PDAC via stress-induced EGFR activation that can be effectively abrogated by EGFR inhibition. These results suggest that dysregulation of ubiquitination is a key mechanism of EGFR hyperactivation in PDAC and that low CBL may define PDAC tumors likely to respond to erlotinib treatment.

BACKGROUND: Whether laparoscopic approach to gastrectomy for gastric cancer (GC) reduces the risk of pneumonia remains unknown. In this study, we compared pneumonia outcomes for patients with GC who underwent either laparoscopic gastrectomy (LG) or open gastrectomy (OG). METHODS: The ACS NSQIP database was queried to identify patients with GC who underwent LG or OG between Jan 2012 - Dec 2018. Outcomes were compared using regression models. A post-hoc analysis was performed for elderly patients. RESULTS: The study cohort included 2661 patients, 23.4 % undergoing LG. Laparoscopic approach lowered pneumonia risk (OR 0.47, p = .028) and reduced hospital length of stay, (5.3 vs 7.1 days, p < .001). Elderly patients undergoing LG demonstrated similar benefits. Risk factors for pneumonia included advanced age, dyspnea and weight-loss, whereas laparoscopic approach reduced this risk. CONCLUSIONS: LG in patients with GC has both statistically and clinically significant advantages over OG with respect to pneumonia. Further studies are needed to validate the relationship between postoperative pneumonia and surgical approach for gastrectomy.

Introduction

Pancreatic ductal adenocarcinoma (PDAC) is projected to rise to the second leading cause of U.S. cancer-related deaths by 2020. Novel therapeutic targets are desperately needed. MicroRNAs (miRs) are small noncoding RNAs that function by suppressing gene expression and are dysregulated in cancer. miR-21 is overexpressed in PDAC tumor cells (TC) and is associated with decreased survival, chemoresistance and invasion. Dysregulation of miR regulatory networks in PDAC tumor-associated fibroblasts (TAFs) have not been previously described. In this study, we show that miR-21 expression in TAFs promotes TC invasion.

Methods

In-situ hybridization for miR-21 was performed on the 153 PDAC patient UCLA tissue microarray and 23 patient-matched lymph node metastases. Stromal and TC histoscores were correlated with clinicopathologic parameters by univariate and multivariate Cox regression. miR-21 positive cells were further characterized by immunofluorescence for mesenchymal/epithelial markers. For in vitro studies, TAFs were isolated from freshly resected human PDAC tumors by the outgrowth method. miR-21 was overexpressed/inhibited in fibroblasts and then co-cultured with GFP-MiaPaCa TCs to assess TC invasion in modified Boyden chambers.

Results

miR-21 was upregulated in TAFs of 78% of tumors, and high miR-21 significantly correlated with decreased overall survival (P = 0.04). Stromal miR-21 expression was also significantly associated with lymph node invasion (P = 0.004), suggesting that it is driving TC spread. Co-immunofluorescence revealed that miR-21 colocalized with peritumoral fibroblasts expressing α-smooth muscle actin. Moreover, expression of miR-21 in primary TAFs correlated with miR-21 in TAFs from patient-matched LN metastases; evidence that PDAC tumor cells induce TAFs to express miR-21. miR-21 expression in TAFs and TCs promotes invasion of TCs and is inhibited with anti-miR-21.

Conclusions

miR-21 expression in PDAC TAFs is associated with decreased overall survival and promotes TC invasion. Anti-miR-21 may represent a novel therapeutic strategy for dual targeting of both tumor and stroma in PDAC.

Background

We previously identified a correlation between increased expression of the phosphoinositide 3-kinase (PI3K) regulatory subunit p85α and improved survival in human pancreatic ductal adenocarcinoma (PDAC). The purpose of this study was to investigate the impact of changes in p85α expression on response to chemotherapy and the regulation of p85α by microRNA-21 (miR-21).

Materials and methods

PDAC tumor cells overexpressing p85α were generated by viral transduction, and the effect of p85α overexpression on sensitivity to gemcitabine was tested by MTT assay. Primary human PDAC tumors were stained for p85α and miR-21 via immunohistochemistry and in situ hybridization, respectively. Additionally, PDAC cells were treated with miR-21 mimic, and changes in p85α and phospho-AKT were assessed by Western blot. Finally, a luciferase reporter assay system was used to test direct regulation of p85α by miR-21.

Results

Higher p85α expression resulted in increased sensitivity to gemcitabine (P < 0.01), which correlated with decreased PI3K-AKT activation. Human tumors demonstrated an inverse correlation between miR-21 and p85α expression levels (r = -0.353, P < 0.001). In vitro, overexpression of miR-21 resulted in decreased levels of p85α and increased phosphorylation of AKT. Luciferase reporter assays confirmed the direct regulation of p85α by miR-21 (P < 0.01).

Conclusions

Our results demonstrate that p85α expression is a determinant of chemosensitivity in PDAC. Additionally, we provide novel evidence that miR-21 can influence PI3K-AKT signaling via its direct regulation of p85α. These data provide insight into potential mechanisms for the known relationship between increased p85α expression and improved survival in PDAC.

Background

Pancreatic ductal adenocarcinoma (PDAC) patients demonstrate highly variable survival within each stage of the American Joint Committee on Cancer (AJCC) staging system. We hypothesize that tumor grade is partly responsible for this variation. Recently our group developed a novel tumor, node, metastasis, grade (TNMG) classification system utilizing Surveillance Epidemiology and End Results (SEER) data in which the presence of high tumor grade results in advancement to the next higher AJCC stage. This study's objective was to validate this TNMG staging system utilizing single-institution data.

Methods

All patients with PDAC who underwent resection at UCLA between 1990 and 2009 were identified. Clinicopathologic data reviewed included age, sex, node status, tumor size, grade, and stage. Grade was redefined as a dichotomous variable. The impact of grade on survival was assessed by Cox regression analysis. Disease was restaged into the TNMG system and compared to the AJCC staging system.

Results

We identified 256 patients who underwent resection for PDAC. Patients with low-grade tumors experienced a 13-month improvement in median survival compared to those with high-grade tumors. On multivariate analysis, tumor grade was the strongest predictor of survival with a hazard ratio of 2.02 (p = 0.0005). Restaging disease according to the novel TNMG staging system resulted in improved survival discrimination between stages compared to the current AJCC system.

Conclusions

We were able to demonstrate that grade is one of the strongest independent prognostic factors in PDAC. Restaging with our novel TNMG system demonstrated improved prognostication. This system offers an effective and convenient way of adding grade to the current AJCC staging system.

Background

Compared to the widely adopted 2-4 months of pre-operative therapy for patients with borderline resectable (BR) or locally advanced (LA) pancreatic ductal adenocarcinoma (PDAC), our institution tends to administer a longer duration before considering surgical resection. Using this unique approach, the aim of this study was to determine pre-operative variables associated with survival.

Methods

Records from patients with BR/LA PDAC who underwent attempt at surgical resection from 1992-2014 were reviewed.

Results

After a median duration of 6 months of pre-operative treatment, 109 patients with BR/LA PDAC (BR 63, LA 46) were explored; 93 (85.3 %) underwent pancreatectomy. Those who received at least 6 months of pre-operative treatment had longer median overall survival (OS) than those who received less (52.8 vs. 32.1 months, P = 0.044). On multivariate analysis, pre-operative treatment duration was the strongest predictor of survival (hazard ratio (HR) 4.79, P = 0.043). However, OS was similar in those whose CA19-9 normalized regardless of whether they received more or less than 6 months of chemotherapy (71.4 vs. 101.8 months, P = 0.930).

Conclusions

Pre-operative CA19-9 decline can guide treatment duration in patients with BR/LA PDAC. We endorse 6 months of therapy except in those patients whose values normalize, where surgery can be considered after a shorter course.

Unlabelled

Pancreatic ductal adenocarcinoma (PDAC) has a characteristically dense stroma comprised predominantly of cancer-associated fibroblasts (CAF). CAFs promote tumor growth, metastasis, and treatment resistance. This study aimed to investigate the molecular changes and functional consequences associated with chemotherapy treatment of PDAC CAFs. Chemoresistant immortalized CAFs (R-CAF) were generated by continuous incubation in gemcitabine. Gene expression differences between treatment-naïve CAFs (N-CAF) and R-CAFs were compared by array analysis. Functionally, tumor cells (TC) were exposed to N-CAF- or R-CAF-conditioned media and assayed for migration, invasion, and viability in vitro Furthermore, a coinjection (TC and CAF) model was used to compare tumor growth in vivo R-CAFs increased TC viability, migration, and invasion compared with N-CAFs. In vivo, TCs coinjected with R-CAFs grew larger than those accompanied by N-CAFs. Genomic analysis demonstrated that R-CAFs had increased expression of various inflammatory mediators, similar to the previously described senescence-associated secretory phenotype (SASP). In addition, SASP mediators were found to be upregulated in response to short duration treatment with gemcitabine in both immortalized and primary CAFs. Inhibition of stress-associated MAPK signaling (P38 MAPK or JNK) attenuated SASP induction as well as the tumor-supportive functions of chemotherapy-treated CAFs in vitro and in vivo These results identify a negative consequence of chemotherapy on the PDAC microenvironment that could be targeted to improve the efficacy of current therapeutic regimens.

Implications

Chemotherapy treatment of pancreatic cancer-associated fibroblasts results in a proinflammatory response driven by stress-associated MAPK signaling that enhances tumor cell growth and invasiveness. Mol Cancer Res; 14(5); 437-47. ©2016 AACR.

Background

mTORC1 activity is dependent on the presence of micronutrients, including Asparagine (Asn), to promote anabolic cell signaling in many cancers. We hypothesized that targeting Asn metabolism would inhibit tumor growth by reducing mTORC1 activity in well-differentiated (WD)/dedifferentiated (DD) liposarcoma (LPS).

Methods

Human tumor metabolomic analysis was utilized to compare abundance of Asn in WD vs. DD LPS. Gene set enrichment analysis (GSEA) compared relative expression among metabolic pathways upregulated in DD vs. WD LPS. Proliferation assays were performed for LPS cell lines and organoid models by using the combination treatment of electron transport chain (ETC) inhibitors with Asn-free media. ¹³C-Glucose-labeling metabolomics evaluated the effects of combination treatment on nucleotide synthesis. Murine xenograft models were used to assess the effects of ETC inhibition combined with PEGylated L-Asparaginase (PEG-Asnase) on tumor growth and mTORC1 signaling.

Results

Asn was enriched in DD LPS compared to WD LPS. GSEA indicated that mTORC1 signaling was upregulated in DD LPS. Within available LPS cell lines and organoid models, the combination of ETC inhibition with Asn-free media resulted in reduced cell proliferation. Combination treatment inhibited nucleotide synthesis and promoted cell cycle arrest. In vivo, the combination of ETC inhibition with PEG-Asnase restricted tumor growth.

Conclusions

Asn enrichment and mTORC1 upregulation are important factors contributing to WD/DD LPS tumor progression. Effective targeting strategies require limiting access to extracellular Asn and inhibition of de novo synthesis mechanisms. The combination of PEG-Asnase with ETC inhibition is an effective therapy to restrict tumor growth in WD/DD LPS.