Siveke, Jens T.

AbstractPancreatic ductal adenocarcinoma (PDAC) is resistant to virtually all chemo‐ and targeted therapeutic approaches. Epigenetic regulators represent a novel class of drug targets. Among them, BET and HDAC proteins are central regulators of chromatin structure and transcription, and preclinical evidence suggests effectiveness of combined BET and HDAC inhibition in PDAC. Here, we describe that TW9, a newly generated adduct of the BET inhibitor (+)‐JQ1 and class I HDAC inhibitor CI994, is a potent dual inhibitor simultaneously targeting BET and HDAC proteins. TW9 has a similar affinity to BRD4 bromodomains as (+)‐JQ1 and shares a conserved binding mode, but is significantly more active in inhibiting HDAC1 compared to the parental HDAC inhibitor CI994. TW9 was more potent in inhibiting tumor cell proliferation compared to (+)‐JQ1, CI994 alone or combined treatment of both inhibitors. Sequential administration of gemcitabine and TW9 showed additional synergistic antitumor effects. Microarray analysis revealed that dysregulation of a FOSL1‐directed transcriptional program contributed to the antitumor effects of TW9. Our results demonstrate the potential of a dual chromatin‐targeting strategy in the treatment of PDAC and provide a rationale for further development of multitarget inhibitors.

NAPOLI-1 (NCT01494506) was a phase III study of liposomal irinotecan (nal-IRI) plus 5-fluorouracil/leucovorin (5-FU/LV) in patients with metastatic pancreatic ductal adenocarcinoma (mPDAC) previously treated with gemcitabine-based therapy. This post hoc analysis of NAPOLI-1 aimed to develop a predictive nomogram for overall survival (OS) at 6 and 12 months. Analyses were derived from all patients in NAPOLI-1 randomized to receive nal-IRI+5-FU/LV, nal-IRI monotherapy, or 5-FU/LV combination therapy. OS was associated with baseline factors using univariate and multivariable Cox analyses. A predictive nomogram was derived and validated using a concordance index and calibration plots. The univariate analyses identified 21 independent factors that contributed to OS, with eight factors significantly associated with OS. The Karnofsky Performance Score contributed the largest number of points (100), followed by presence of liver metastasis (98) and randomization to nal-IRI+5-FU/LV (96). The other baseline factors showing effects were albumin (g/dL), neutrophil/lymphocyte ratio, carbohydrate antigen 19-9 (U/mL), disease stage at diagnosis, and body mass index (kg/m2). The nomogram was used to predict the 6- and 12-month survival probability. The mean absolute errors between the observed and predicted probabilities for OS at 3, 6, and 9 months were 0.07, 0.08, and 0.07, respectively. This nomogram, based on NAPOLI-1, provides additional insight to aid decision-making for patients with mPDAC after previous gemcitabine-based therapy.

Abstract Cancer-associated inflammation is a molecular key feature in pancreatic ductal adenocarcinoma. Oncogenic KRAS in conjunction with persistent inflammation is known to accelerate carcinogenesis, although the underlying mechanisms remain poorly understood. Here, we outline a novel pathway whereby the transcription factors NFATc1 and STAT3 cooperate in pancreatic epithelial cells to promote KrasG12D-driven carcinogenesis. NFATc1 activation is induced by inflammation and itself accelerates inflammation-induced carcinogenesis in KrasG12D mice, whereas genetic or pharmacologic ablation of NFATc1 attenuates this effect. Mechanistically, NFATc1 complexes with STAT3 for enhancer–promoter communications at jointly regulated genes involved in oncogenesis, for example, Cyclin, EGFR and WNT family members. The NFATc1–STAT3 cooperativity is operative in pancreatitis-mediated carcinogenesis as well as in established human pancreatic cancer. Together, these studies unravel new mechanisms of inflammatory-driven pancreatic carcinogenesis and suggest beneficial effects of chemopreventive strategies using drugs that are currently available for targeting these factors in clinical trials. Significance: Our study points to the existence of an oncogenic NFATc1–STAT3 cooperativity that mechanistically links inflammation with pancreatic cancer initiation and progression. Because NFATc1–STAT3 nucleoprotein complexes control the expression of gene networks at the intersection of inflammation and cancer, our study has significant relevance for potentially managing pancreatic cancer and other inflammatory-driven malignancies. Cancer Discov; 4(6); 688–701. ©2014 AACR. This article is highlighted in the In This Issue feature, p. 621