Research advances in the molecular classification of gastric cancer.

Gastric cancer (GC) is a malignant tumor with one of the lowest five-year survival rates. Traditional first-line treatment regimens, such as platinum drugs, have limited therapeutic efficacy in treating advanced GC and significant side effects, greatly reducing patient quality of life. In contrast, trastuzumab and other immune checkpoint inhibitors, such as nivolumab and pembrolizumab, have demonstrated consistent and reliable efficacy in treating GC. Here, we discuss the intrinsic characteristics of GC from a molecular perspective and provide a comprehensive review of classification and treatment advances in the disease. Finally, we suggest several strategies based on the intrinsic molecular characteristics of GC to aid in overcoming clinical challenges in the development of precision medicine and improve patient prognosis.

VNN1 overexpression in pancreatic cancer cells inhibits paraneoplastic islet function by increasing oxidative stress and inducing ß­cell dedifferentiation.

Vanin­1 (VNN1) may be a potential biomarker for the early screening of pancreatic cancer (PC)­associated diabetes (PCAD). A previous study by the authors reported that cysteamine secreted by VNN1­overexpressing PC cells induced the dysfunction of paraneoplastic insulinoma cell lines by increasing oxidative stress. In the present study, it was observed that both cysteamine and exosomes (Exos) secreted by VNN1­overexpressing PC cells aggravated the dysfunction of mouse primary islets. PC­derived VNN1 could be transported into islets through PC cell­derived Exos (PC­Exos). However, ß­cell dedifferentiation, and not cysteamine­mediated oxidative stress, was responsible for the islet dysfunction induced by VNN1­containing Exos. VNN1 inhibited the phosphorylation of AMPK and GAPDH, and prevented Sirt1 activation and FoxO1 deacetylation in islets, which may be responsible for the induction of ß­cell dedifferentiation induced by VNN1­overexpressing PC­Exos. Furthermore, it was demonstrated that VNN1­overexpressing PC cells further impaired the functions of paraneoplastic islets in vivo using diabetic mice with islets transplanted under the kidney capsule. On the whole, the present study demonstrates that PC cells overexpressing VNN1 exacerbate the dysfunction of paraneoplastic islets by inducing oxidative stress and ß­cell dedifferentiation.

HER2 protein expression correlates with Lauren classification and P53 in gastric cancer patients.

Human epidermal growth factor receptor 2 (HER2) is a key pathological characteristic of gastric cancer (GC). However, the clinical significance of HER2 expression in gastric carcinoma remains controversial. The purpose of this study was to analyze the clinicopathological characteristics of HER2 protein expression, Lauren classification and tumor protein p53 (P53) expression and to evaluate the clinical significance of HER2 protein expression. A total of 176 consecutive patients were prospectively recruited between January 2014 and December 2016 at the Second Affiliated Hospital of Zhejiang University School of Medicine. Histological analysis of the resected tissue was performed for HER2 protein expression using immunohistochemistry (IHC) and fluorescence in situ hybridization (FISH). Additionally, the expression status of HER2 protein and clinicopathological features were analyzed using the chi-squared (χ2) test. Survival analysis was performed using the Kaplan-Meier method, and differences between the survival curves were determined using the log-rank test. All statistical analyses were conducted using SPSS 22.0 statistical software program (IBM Corp., Armonk, NY). A total of 176 patients with GC were enrolled in this study. Intratumoral heterogeneity of HER2 protein overexpression was observed in 42 of 176 cases with IHC grade 2+, accompanied by FISH positivity and IHC grade 3+. HER2 protein expression was correlated with tumor differentiation (P < .001), Lauren classification (P = .001), Borrmann type (P = .003) and P53 expression (P < .001). HER2 protein positivity was associated with significantly higher overall survival (OS) (P = .038). Overexpression of HER2 protein was observed in 23.9% of the cases and was significantly related to the Lauren intestinal subtype and P53 negative expression. HER2 protein overexpression was independently associated with higher OS.

Depletion of C12orf48 inhibits gastric cancer growth and metastasis via up-regulating Poly r(C)-Binding Protein (PCBP) 1.

BACKGROUND: Gastric cancer remains a major cause of cancer-related death worldwide. C12orf48, also named PARP1 binding protein, is over-expressed in several cancers. However, the expression profile and potential roles of C12orf48 in gastric cancer are largely unknown. METHODS: We used bioinformatics approaches and tissue microarray immunohistochemistry to analyze the expression profile of C12orf48 in gastric cancer tissues. Plasmid-mediated over-expression or knockdown were performed. CCK-8 assays and flow cytometry were employed to evaluate cellular proliferation and apoptosis respectively. Transwell assays were used to assess migrative and invasive abilities. The roles of C12orf48 were also evaluated in a xenograft tumor model. RESULTS: We found that C12orf48 was over-expressed in gastric cancer tissue, which associated with advanced stage and poor prognosis. In vitro and in vivo experiments showed depletion of C12orf48 attenuated cancer growth, while facilitated apoptosis. Further, the expression of Poly r(C)-Binding Protein (PCBP) 1 was found negatively regulated by C12orf48. Intended up-regulation of PCBP1 prevented C12orf48-mediated proliferation and rescued cells from apoptosis. Besides, C12orf48 promoted cellular migration and invasion, with E-cadherin down-regulated while vimentin and N-cadherin up-regulated, which was reversed by up-regulated PCBP1. CONCLUSIONS: Our findings indicate that depletion of C12orf48 inhibited gastric cancer growth and metastasis via up-regulating PCBP1. Targeting C12orf48-PCBP1 axis may be a potential therapeutic strategy.

Immune checkpoint inhibition for pancreatic ductal adenocarcinoma: limitations and prospects: a systematic review.

Pancreatic cancer is an extremely malignant tumor with the lowest 5-year survival rate among all tumors. Pancreatic ductal adenocarcinoma (PDAC), as the most common pathological subtype of pancreatic cancer, usually has poor therapeutic results. Immune checkpoint inhibitors (ICIs) can relieve failure of the tumor-killing effect of immune effector cells caused by immune checkpoints. Therefore, they have been used as a novel treatment for many solid tumors. However, PDAC is not sensitive to monotherapy with ICIs, which might be related to the inhibitory immune microenvironment of pancreatic cancer. Therefore, the way to improve the microenvironment has raised a heated discussion in recent years. Here, we elaborate on the relationship between different immune cellular components in this environment, list some current preclinical or clinical attempts to enhance the efficacy of ICIs by targeting the inhibitory tumor microenvironment of PDAC or in combination with other therapies. Such information offers a better understanding of the sophisticated tumor-microenvironment interactions, also providing insights on therapeutic guidance of PDAC targeting. Video Abstract.

Dickkopf-related protein 3 alters aerobic glycolysis in pancreatic cancer BxPC-3 cells, promoting CD4+ T-cell activation and function.

BACKGROUND: To investigate the value of Dickkopf-related protein 3 (DKK3) on aerobic glycolysis in pancreatic cancer cells, where DKK3-overexpression is used to determine its effects on CD4+ T cells. METHODS: The BxPC-3-DKK3 cell line was constructed, and peripheral blood mononuclear cell (PBMC) was prepared. After isolated the CD4+ T cells, the lactic acid, glucose uptake ability, cellular viability, proliferation, apoptosis, and markers were detected by PCR and western blot, and the concentrations of multiple cytokines were determined using the ELISA method. RESULTS: After co-culture with pancreatic cancer cells overexpressing DKK3, the glucose uptake markedly, proliferation enhanced and apoptosis inhibited in CD4+ T cells. The co-culture model also revealed that DKK3-overexpression promotes the activation and regulates the metabolism and function of CD4+ T cells. CONCLUSIONS: DKK3 alters the metabolic microenvironment of pancreatic cancer cells and further facilitates the function of CD4+ T cells which suggesting that DKK3 may have a therapeutic potential in pancreatic cancer.

De-Ubiquitinating Enzymes USP21 Regulate MAPK1 Expression by Binding to Transcription Factor GATA3 to Regulate Tumor Growth and Cell Stemness of Gastric Cancer.

USP21 is a kind of deubiquitinating enzymes involved in the malignant progression of various cancers, while its role in gastric cancer (GC) and the specific molecular mechanism are still unclear. This study probed into the function of USP21 in vitro and in vivo, and discussed the regulatory mechanism of USP21 in GC in vitro. We reported that USP21 promoted GC cell proliferation, migration, invasion, and stemness in vitro, and regulated GC tumor growth and cell stemness in mice in vivo. USP21 stabilized the expression of GATA3 by binding to GATA3. Besides, GATA3 also regulated the expression of MAPK1 at the transcriptional level. A series of in vitro experiments testified that USP21 regulated the expression of MAPK1 by binding to transcription factor GATA3, thereby regulating the tumor growth and cell stemness of GC. Overall, this study identified a new USP21/GATA3/MAPK1 axis, which plays a pivotal role in promoting the malignant progression of GC and might provide a potential target for treatment.

Ceritinib increases sensitivity of AKT inhibitors to gastric cancer.

Gastric cancer (GC), known for high morbidity and mortality, is poorly prognosed with traditional chemotherapy and biological agents. Current studies have found that over-activation of AKT is a common molecular characteristic in GC. Although the development of this targeted inhibitor has entered clinical phases, limited success is reported because of its compensatory signaling pathways. Here, we found that GC cell lines with high phosphorylation of AKT show different sensitivity to AKT inhibitors (AKTis), but a reduction of p-GSK3ß related sensitivity of AKTis in GC cells. Besides, we revealed that Ceritinib exerted a strongly synergistic antitumor effect with AKT inhibitors both in vitro and in vivo. Obviously, Ceritinib improved the sensitivity of Capivasertib (AZD5363, AKTs) and Afuresertib (GSK2110183, AKTis) in gastric cancer cells, as illustrated by a significant reduction in the GC cell proliferation and enhanced apoptosis. The drug combination showed tumor regression in BALB/c (nu/nu) mouse MKN45 (Gastric cancer), tumor model. Also, the combination strategy indicated significantly low p-AKT levels due to AKTis compensation and reduced the levels of p-GSK3ß in both GC cell lines and GC patient-derived cells. These findings may provide a novel combination strategy for gastric cancer treatment.

Patterns of recurrence after curative D2 resection for gastric cancer: Implications for postoperative radiotherapy.

BACKGROUND: High-quality randomized controlled trials have demonstrated the benefit of radiotherapy (RT) in patients with radical resected gastric cancer (GC), however, utilization rates of postoperative RT remain remarkably low. Patterns, incidences, and time of recurrence provide biological bases for clinical monitoring of GC patients and guiding potential complementary therapies. Thus, the aim of this study is to understand the location of locoregional recurrence which may allow individualized RT strategies and minimize radiation-related toxic effects. METHODS: A relatively large sample of GC patients in a single institution who had undergone curative D2 resection was retrospectively reviewed and the relevant recurrence patterns were illustrated. Independent recurrence-related risk factors were analyzed by logistic regression analysis. New logistic regression models were further developed to predict the probability of recurrence. RESULTS: Overall, among 776 GC patients who had continuous and complete follow-up data, 300 cases relapsed after curative resection. Lymphovascular invasion, lymph node metastases, and tumor stage were indicators for early recurrence. Peritoneal, regional, local, and distant recurrence initially occurred in 51 (6.6%), 151 (19.4%), 56 (7.2%), and 164 (21.1%) patients, respectively. Among patients with regional recurrence, the most common sites were lymph node stations 16a2, 8, 12, 16b1, and 9. Remnant stomach recurrence was not so prominent that it seemed reasonable to be excluded from an irradiation field for patients with negative surgical/pathologic margins. CONCLUSIONS: For GC patients who underwent radical D2 resection, distant and regional recurrences were still common. Besides, optimizing regional control of lymph nodes outside the D2 dissected area was crucial for rational design of the RT field. Furthermore, the new logistic regression models might act as useful tools to evaluate recurrence risk and determine which patients should receive postoperative chemoradiotherapy.

Resection of GIST in the duodenum and proximal jejunum: A retrospective analysis of outcomes.

INTRODUCTION: Gastrointestinal stromal tumors (GISTs), with a primary occurrence in the duodenum and proximal jejunum, are rare and treatment is poorly understood. This study aimed to evaluate the main factors influencing the prognosis of GIST resection in this complex anatomical structure. MATERIALS AND METHODS: This retrospective study included 47 patients who underwent surgery for primary GIST of the duodenum (20) and proximal jejunum (27) between 2012 and 2017. Perioperative clinical data as well as relapse and survival information were collected. RESULTS: All patients underwent negative margin resection (R0) of duodenal and proximal jejunum GISTs. Complications occurred more frequently in treatment of duodenal GISTs than proximal jejunum GISTs (p = 0.003). GISTs in D3 (the 3rd portion of duodenum) were related to larger tumor size (p = 0.001), higher probability of severe complication rate (p = 0.042), longer hospital stays (p = 0.023) and fasting time (p = 0.020). More complications were found for patients with digestive reconstruction than limited resection (p = 0.010). Additionally, patients with a tumor mass larger than 5 cm or a mitotic index greater than 5 mitoses/50 HPFs showed poorer therapeutic outcomes. The 1- and 3-year overall survival was 97.9% and 86.1%, respectively and were not influenced by operation type (p = 0.061) or GIST position (p = 0.447). CONCLUSION: With negative operational margins, limited resection is a safe and feasible procedure for duodenal and proximal jejunum GIST patients and unnecessary digestive reconstruction should be avoided. Considering the severe complication rate, resection for GISTs in D3 should be performed with care.

Thymidylate synthase prompts metastatic progression through the dTMP associated EMT process in pancreatic ductal adenocarcinoma.

As a fundamental metabolic enzyme, anti-Thymidylate synthase (TS) strategy has been shown to be an effective therapy for human cancers. However, the genuine effects of TS in pancreatic ductal adenocarcinoma (PDA) are still conflicting. We systemically assessed the prognostic value and whether TS associated with malignant progression in PDA. Protein and mRNA expression level of TS were evaluated in en bloc PDA samples, the prognostic effect of TS expressed in cytoplasm or cytonuclear was determined separately in the first time. The impact of TS on tumor cell behaviors was assessed in in vitro assays, and the TS associated metastatic potential was further determined in two different PDA metastatic models. The retrospective clinical analysis firstly demonstrated that tumor cytonuclear TS expression was positively correlated with lymphatic metastasis and negatively correlated with the overall survival (OS) in PDA patients. The subsequent experiments further confirmed that TS depletion can effectively abate EMT (epithelial to mesenchymal) process in in vitro and decline most of the metastatic lesions in two different PDA mice models, and the deoxythymidine monophosphate (dTMP) biosynthesis malfunction resulted imbalanced dNTP pools may be the fundamental causation. Collectively, the present study suggested the prospective strategy of combined anti-TS scheme for metastatic PDA, and we strongly suggest further clinical standardization research with a large cohort to verify the prognostic value and the therapeutic potential of TS in PDA.

Changes in mitochondrial function during EMT induced by TGFß-1 in pancreatic cancer.

Mitochondrial dysfunction is linked to cancer. Differences in the number, morphology and function of mitochondria have been observed between normal cells and cancer cells. However, changes in mitochondrial function during epithelial-mesenchymal transition (EMT) in pancreatic cancer are less known. In the present study, the cultured human pancreatic cancer cell line Panc-1 was treated with transforming growth factor (TGF)ß-1. Mitochondrial functions following TGFß-1 exposure in pancreatic cancer were investigated. It was noticed that TGFß-1 treatment induces morphologic changes and a shift from epithelial to mesenchymal phenotype in pancreatic cancer. Furthermore, increased mitochondrial mass was detected in pancreatic cancer following TGFß-1 treatment. Besides, the production of reactive oxygen species in TGFß-1-treated pancreatic cancer cells significantly increased compared with the control cells. Our results indicate that the phenomenon of EMT in pancreatic cancer has an association with mitochondrial dysfunction. Mitochondrial dysfunction may be a cause of EMT in pancreatic cancer, which leads to heterogeneity in pancreatic cancer, and may be a potential therapeutic target in the future.

Mesenteric fibromatosis after resection for gastrointestinal stromal tumor of stomach: A case report.

RATIONALE: Gastrointestinal stromal tumor and mesenteric fibromatosis are rare mesenchymal tumors. Coexistence of these two diseases is uncommon, with only a few anecdotal reports of individuals. PATIENT CONCERNS: Clinical data and treatment of a 43-year-old man with subsequent mesenteric fibromatosis from gastrointestinal stromal tumor are summarized. The Ethics Committee of The Second Affiliated Hospital, College of Medicine, Zhejiang University approved this study, and the patient provided written informed consent form. DIAGNOSES: The initial diagnosis of the recurrent mesenteric mass was recurrent gastrointestinal stromal tumor. INTERVENTIONS: The operation was performed as possible at the time when the mass was found after the first surgery. OUTCOMES: The diagnosis was revised as mesenteric fibromatosis according to the postoperative immunohistochemical staining. The postoperative condition was normal without adjuvant therapy and no recidivation has been found. LESSONS: The potential for the coexistence of gastrointestinal stromal tumor and mesenteric fibromatosis should always be considered.

VNN1, a potential biomarker for pancreatic cancer-associated new-onset diabetes, aggravates paraneoplastic islet dysfunction by increasing oxidative stress.

In our previous clinical microarray analysis, we were the first to report on Vanin-1 (VNN1) as a novel clinically derived biomarker of pancreatic cancer-associated new-onset diabetes (PCAND). The functional mechanisms of VNN1 in the pathogenesis of PCAND, however, are not completely understood. In the present study, we further extend our previous clinical study to include laboratory research. The functions and mechanisms of neoplastic overexpressed VNN1 in PCAND have been explored using a co-culture model. Furthermore, the serum concentrations and discrimination power of downstream molecules of VNN1 were tested in a PCAND cohort. Pancreatic ductal adenocarcinoma (PDA) overexpressed VNN1 further aggravates paraneoplastic islet dysfunction; decreases in GSH/PPAR-γ concentrations and increases in ROS/cysteamine might be primary cause of this effect. Clinical serum analyses revealed that the expression profiles of these molecules were aberrant in the PCAND group. Our results further demonstrated that PCAND is a type of paraneoplastic diabetes. As the only clinically derived biomarker for PCAND screening available today, the biological role of VNN1 in triggering oxidative stress within the pancreatic microenvironment is important. The molecules downstream of VNN1 are also potential biomarkers for PCAND screening.

A case of neurofibromatosis complicated with small bowel obstruction / 浙江大学学报·医学版

Neurofibromatosis type 1(NF-1) with gastrointestinal stromal tumor (GIST) is a rare case in clinical practice. But it is even rarer that the GIST tumor in this case is so large that it cause small intestinal obstruction. Here we report such a male case of NF-1,with positive family history of NF-1 and nodules all over the patient's skin and abdominal cavity. The patient came to hospital with a sudden upper abdominal pain and nausea and vomiting over 5 d. Abdominal computerized tomography (CT) showed that there were numerous nodules of different size in his abdominal cavity. And the largest one is about 10 cm in diameter,which oppressed the small bowel and caused the small bowel mesenteric volvulus and obstruction of the bowel. Finally,the tumor was pathologically proved to be a GIST tumor but not NF nodule. The patient stays healthy until now after operation.

Inhibition of autophagy promotes metastasis and glycolysis by inducing ROS in gastric cancer cells.

Autophagy defect has been shown to be correlated with malignant phenotype and poor prognosis of human cancers, however, the detailed mechanisms remain obscure. In this study, we investigated the biological changes induced by autophagy inhibition in gastric cancer. We showed that inhibition of autophagy in gastric cancer cells promotes epithelial-mesenchymal transition (EMT) and metastasis, alters metabolic phenotype from mitochondrial oxidative phosphorylation to aerobic glycolysis and converts cell phenotype toward malignant, which maybe further contribute to chemoresistance and poor prognosis of gastric cancer. We also identified that the EMT and metabolism alterations induced by autophagy inhibition were dependent on ROS-NF-κB-HIF-1α pathway. More importantly, scavenging of ROS by the antioxidant N-acetylcysteine (NAC) attenuated activation of NF-κB and HIF-1α in autophagy-deficient gastric cancer cells, and autophagy inhibition induced metastasis and glycolysis were also diminished by NAC in vivo. Taken together, our findings suggested that autophagy defect promotes metastasis and glycolysis of gastric cancer, and antioxidants could be used to improve disease outcome for gastric cancer patients with autophagy defect.

DKK3 blocked translocation of ß-catenin/EMT induced by hypoxia and improved gemcitabine therapeutic effect in pancreatic cancer Bxpc-3 cell.

The Wnt/ß-catenin signalling pathway is activated in pancreatic cancer initiation and progression. Dickkopf-related protein 3 (DKK3) is a member of the human Dickkopf family and an antagonist of Wnt ligand activity. However, the function of DKK3 in this pathway in pancreatic cancer is rarely known. We examined the expression of DKK3 in six human pancreatic cancer cell lines, 75 pancreatic cancer and 75 adjacent non-cancerous tissues. Dickkopf-related protein 3 was frequently silenced and methylation in pancreatic cancer cell lines (3/6). The expression of DKK3 was significantly lower in pancreatic cancer tissues than in adjacent normal pancreas tissues. Further, ectopic expression of DKK3 inhibits nuclear translocation of ß-catenin induced by hypoxia in pancreatic cancer Bxpc-3 cell. The forced expression of DKK3 markedly suppressed migration and the stem cell-like phenotype of pancreatic cancer Bxpc-3 cell in hypoxic conditions through reversing epithelial-mesenchymal transition (EMT). The stable expression of DKK3 sensitizes pancreatic cancer Bxpc-3 cell to gemcitabine, delays tumour growth and augments gemcitabine therapeutic effect in pancreatic cancer xenotransplantation model. Thus, we conclude from our finding that DKK3 is a tumour suppressor and improved gemcitabine therapeutic effect through inducing apoptosis and regulating ß-catenin/EMT signalling in pancreatic cancer Bxpc-3 cell.

Analysis of a cytoskeleton-associated kinase PEAK1 and E-cadherin in gastric cancer.

The expression of pseudopodium-enriched atypical kinase 1(PEAK1) has been studied in human cancers. However, their roles in gastric cancer are still unknown. In this study, gastric cancer tissue microarrays were constructed with 159 gastric cancer tissue samples, 150 non-neoplastic gastric epithelium specimens and 152 lymph node samples. Immunohistochemical staining for PEAK1 and E-cadherin was performed. Our study found negative expression of PEAK1 in 113 of 159 (71.1%) gastric cancers, in 46 of 150 (30.7%) non-neoplastic gastric epithelium tissues and in 69 of 94 (73.4%) metastatic lymph nodes. Negative expression of PEAK1 and E-cadherin associated with tumor grading, depth of invasion, lymph node metastases, pTNM stage and macroscopic type. Patients with either positive PEAK1 or E-cadherin expression had a significantly higher survival than those with negative expression. When combined, PEAK1(-)/E-cadherin(-) had a significantly poor prognosis than the rest of the patients. The expression of PEAK1 protein was positively correlated with E-cadherin in cancer tissues. Cox regression analyses showed that PEAK1, E-cadherin and PEAK1(-)/E-cadherin(-) were independent predictors of overall survival. In conclusion, our findings suggest that loss of PEAK1 may play an important role in carcinogenesis and development of gastric cancer through activating epithelial to mesenchymal transition.

Early changes in apparent diffusion coefficient as an indicator of response to sorafenib in hepatocellular carcinoma.

OBJECTIVE: The relationship between apparent diffusion coefficient (ADC) and chemotherapy has been established. However, whether ADC could be considered as a measure for monitoring response to sorafenib in hepatocellular carcinoma (HCC) has not been demonstrated. This study was to investigate the ADC changes of advanced HCC under sorafenib treatment. METHODS: Athymic mice with HepG2 xenografts were allocated to two groups: control and sorafenib (40 mg/kg, bid). T2 and diffusion images were acquired at each time point (0, 10, 14, and 18 d post-therapy). Tumor volume and changes in ADC were calculated. RESULTS: Tumor volumes on Days 10, 14, and 18 after treatment showed significant decreases in the sorafenib-treated group compared with the control. Pretreatment ADC values were not significantly different between the control and treated groups. A slow increase in ADC in the peripheral zone of tumors appeared in the treated group, which was significantly higher compared with the control group on Days 10, 14, and 18. In the central part of tumors on Day 10 after treatment, an increase in ADC appeared in the treated and control groups, the ADC of the control group being significantly lower compared with the treated tumors. From Day 10 to Day 14, the ADC map showed a progressive decrease in the central region of tumors in the treated and control groups. However, this change is more significant in the treated groups. CONCLUSIONS: Early changes in mean ADC correlated with sorafenib treatment in HCC, which are promising indicators for predicting sorafenib response in this carcinoma.

Inhibition of SIRT1 combined with gemcitabine therapy for pancreatic carcinoma.

BACKGROUND: Pancreatic carcinoma possesses one of the highest lethality rates, highest drug-resistance, and highest incidence rates. The objective of this research was to enhance the efficacy and drug-resistance for pancreatic carcinoma by using inhibition of SIRT1 combined with gemcitabine therapy methods. METHODS: Three pancreatic carcinoma cells (PANC-1 cells, BxPC-3 cells, and SW1990 cells) received treatment with physiological saline, inhibition of SIRT1, gemcitabine, and combination therapy with inhibition of SIRT1 and gemcitabine in vitro; then BxPC-3 pancreatic cancer xenogeneic mice also received treatment with physiological saline, inhibition of SIRT1, gemcitabine, and combination therapy with inhibition of SIRT1 and gemcitabine in vivo. RESULTS: The cleaved poly ADP ribose polymerase (PARP)-1 effect of drug in pancreatic carcinoma cells was significantly different (P < 0.05) and the efficacy in descending order was the combination therapy with inhibition of SIRT1 and gemcitabine, inhibition of SIRT1, and gemcitabine. The BxPC-3 pancreatic cancer xenogeneic mice model received treatment with physiological saline, inhibition of SIRT1, gemcitabine, and combination therapy with inhibition of SIRT1 and gemcitabine in vivo and the results showed that the tumor volumes decreased and the survival rate within 45 days increased according to the order of the given drugs and the difference was significant (P < 0.05). CONCLUSION: Combination therapy with inhibition of SIRT1 and gemcitabine could improve efficacy and survival time in a BxPC-3 pancreatic cancer xenogeneic mice model, compared with single inhibition of SIRT1, or single gemcitabine therapy. The combination therapy method is a potential treatment method for pancreatic carcinoma.