Pancreatic ductal adenocarcinoma (PDAC) exhibits severe hypoxia, which is associated with chemoresistance and worse patient outcome. It has been reported that hypoxia induces metabolic reprogramming in cancer cells. However, it is not well known whether metabolic reprogramming contributes to hypoxia. Here, we established that increased glutamine catabolism is a fundamental mechanism inducing hypoxia, and thus chemoresistance, in PDAC cells. An extracellular matrix component–based in vitro three-dimensional cell printing model with patient-derived PDAC cells that recapitulate the hypoxic status in PDAC tumors showed that chemoresistant PDAC cells exhibit markedly enhanced glutamine catabolism compared with chemoresponsive PDAC cells. The augmented glutamine metabolic flux increased the oxygen consumption rate via mitochondrial oxidative phosphorylation (OXPHOS), promoting hypoxia and hypoxia-induced chemoresistance. Targeting glutaminolysis relieved hypoxia and improved chemotherapy efficacy in vitro and in vivo. This work suggests that targeting the glutaminolysis–OXPHOS–hypoxia axis is a novel therapeutic target for treating patients with chemoresistant PDAC. Significance: Increased glutaminolysis induces hypoxia via oxidative phosphorylation-mediated oxygen consumption and drives chemoresistance in pancreatic cancer, revealing a potential therapeutic strategy of combining glutaminolysis inhibition and chemotherapy to overcome resistance.

Pancreatic cancer remains one of the most lethal cancers. These patients often have multiple symptoms, and integrated supportive care is critical in helping them remain well for as long as possible. Fluorouracil-based chemotherapy is known to improve overall survival (OS) by approximately 3 months, compared to the best supportive care alone. A 1997 study comparing gemcitabine and fluorouracil treatment of advanced pancreatic cancer patients showed an improvement in OS of 1 month in patients receiving gemcitabine. Over the next 10 years, multiple randomized studies compared singleagent gemcitabine with combination chemotherapy and showed no effective survival improvement. However, the addition of erlotinib, an epidermal growth factor receptor (EGFR) inhibitor, was associated with a significant improvement in OS of approximately 2 weeks. However, adoption of this regimen has not been widespread because of its limited effect and added toxicity. Two clinical trials have recently prolonged OS in advanced pancreatic cancer patients by almost 1 year. The first compared FOLFIRINOX with gemcitabine alone, and was associated with a significant improvement in median survival. The second compared gemcitabine and nabpaclitaxel with gemcitabine alone, and was associated with improvements in OS. At present, these regimens are considered standard treatment for patients with good performance statuses.

Pancreatic cancer is predominantly lethal, and is primarily treated using gemcitabine, with increasing resistance. Therefore, novel agents that increase tumor sensitivity to gemcitabine are needed. Histone deacetylase (HDAC) inhibitors are emerging therapeutic agents, since HDAC plays an important role in cancer initiation and progression. We evaluated the antitumor effect of a novel HDAC inhibitor, CG200745, combined with gemcitabine/erlotinib on pancreatic cancer cells and gemcitabine-resistant pancreatic cancer cells. Three pancreatic cancer-cell lines were used to evaluate the antitumor effect of CG200745 combined with gemcitabine/erlotinib. CG200745 induced the expression of apoptotic proteins (PARP and caspase-3) and increased the levels of acetylated histone H3. CG200745 with gemcitabine/erlotinib showed significant growth inhibition and synergistic antitumor effects in vitro. In vivo, gemcitabine/erlotinib and CG200745 reduced tumor size up to 50%. CG200745 enhanced the sensitivity of gemcitabine-resistant pancreatic cancer cells to gemcitabine, and decreased the level of ATP-binding cassette-transporter genes, especially multidrug resistance protein 3 (MRP3) and MRP4. The novel HDAC inhibitor, CG200745, with gemcitabine/erlotinib had a synergistic anti-tumor effect on pancreatic cancer cells. CG200745 significantly improved pancreatic cancer sensitivity to gemcitabine, with a prominent antitumor effect on gemcitabine-resistant pancreatic cancer cells. Therefore, improved clinical outcome is expected in the future.

Nutritional status affects the prognosis of various tumors. The prognostic nutritional index (PNI) is the known predictor of postoperative outcome in resectable pancreatic cancer patients. This study aimed to validate the prognostic value of PNI in all stages of pancreatic cancer. We retrospectively reviewed 499 patients with pancreatic cancer who were diagnosed at Severance Hospital between January 2006 and December 2011. The PNI value was calculated as 10 × serum albumin (g/dL) + 0.005 × total lymphocyte count (/mm³) at initial diagnosis. The median patient age was 62 yr, and 289 were men. The study group comprised resectable disease (n = 121), locally advanced disease (n = 118), and metastatic disease (n = 260). Univariate and multivariate analysis revealed that PNI ≤ 49.5 at initial diagnosis, together with performance status, platelet count, and clinical stage, was significantly associated with overall survival (hazard ratio, 1.562; all P < 0.05). Patients with PNI ≤ 49.5 (n = 208) had shorter median overall survival compared to patients with high PNI (9.8 vs. 14.2 mo; log rank, P < 0.001). In clinical stage subgroup analysis, initial PNI ≤49.5 independently predicted shorter overall survival, especially in resectable and metastatic disease (P = 0.041, P = 0.002, respectively).

To clarify the role of neoadjuvant concurrent chemoradiotherapy (NACCRT) followed by surgical resection for localized or locally advanced perihilar cholangiocarcinoma (CCA). We retrospectively reviewed 57 patients who underwent surgical resection with or without NACCRT for perihilar CCA; 12 patients received NACCRT and 45 patients did not received NACCRT. Patients with locally advanced perihilar CCA requiring NACCRT were defined as follows: (1) a mass involving unilateral branches of the portal vein or hepatic artery with insufficient volume of the anticipated remnant lobe; or (2) an infiltrating mass in the main portal vein that was too long for reconstruction, identified at preoperative staging. The median disease-free survival (DFS) durations of the neoadjuvant and non-neoadjuvant CCRT groups were 26.0 and 15.1 mo, respectively (P = 0.91). The median overall survival (OS) durations of the neoadjuvant and non-neoadjuvant CCRT groups were 32.9 and 27.1 mo, respectively (P = 0.26). The NACCRT group showed a downstaging tendency compared to the non-NACCRT group as compared with the tumor stage confirmed by histological examination after surgery and the tumor stage confirmed by imaging test at the time of diagnosis (P = 0.01). NACCRT does not prolong DFS and OS in localized or locally advanced perihilar CCA. However, NACCRT may allow tumor downstaging and improve tumor resectability.

Statins are cholesterol-lowering medications that are associated with a number of signaling pathways involved in carcinogenesis. Recent observational studies raised the possibility that the use of statins may reduce overall mortality in various types of cancer. We investigated whether statins used after pancreatic cancer diagnosis are associated with longer survival in pancreatic cancer patients.We retrospectively analyzed data from 1761 patients newly diagnosed with pancreatic adenocarcinoma between January 1, 2006, and December 31, 2014. We used the time-dependent Cox proportional hazards regression model to estimate mortality among pancreatic cancer patients according to statin use.Among the 1761 pancreatic cancer patients, 118 patients had used statins. During the study period, 1176 patients (66.7%) died. After adjusting for age, sex, location of cancer, cancer stage, diabetes mellitus, hypertension, dyslipidemia, smoking, alcohol use, body mass index, and CA 19-9, statin use was associated with a lower risk of cancer death (hazard ratio [HR], 0.780; 95% confidence interval [CI], 0.617-0.986), especially among simvastatin users (HR, 0.554; 95% CI, 0.312-0.982) and atorvastatin users (HR, 0.636; 95% CI, 0.437-0.927). Subgroup analysis showed that overall survival was statistically significantly longer in patients with nonmetastatic pancreatic cancer (log-rank P = 0.024).We found that the use of simvastatin and atorvastatin after cancer diagnosis is associated with longer survival in patients with nonmetastatic pancreatic adenocarcinoma.