Cristina R. Ferrone

Glutamine supports pancreatic cancer growth through a Kras-regulated metabolic pathway

Cancer cells have metabolic dependencies that distinguish them from their normal counterparts. Among these dependencies is an increased use of the amino acid glutamine to fuel anabolic processes. Indeed, the spectrum of glutamine-dependent tumours and the mechanisms whereby glutamine supports cancer metabolism remain areas of active investigation. Here we report the identification of a non-canonical pathway of glutamine use in human pancreatic ductal adenocarcinoma (PDAC) cells that is required for tumour growth. Whereas most cells use glutamate dehydrogenase (GLUD1) to convert glutamine-derived glutamate into α-ketoglutarate in the mitochondria to fuel the tricarboxylic acid cycle, PDAC relies on a distinct pathway in which glutamine-derived aspartate is transported into the cytoplasm where it can be converted into oxaloacetate by aspartate transaminase (GOT1). Subsequently, this oxaloacetate is converted into malate and then pyruvate, ostensibly increasing the NADPH/NADP+ ratio which can potentially maintain the cellular redox state. Importantly, PDAC cells are strongly dependent on this series of reactions, as glutamine deprivation or genetic inhibition of any enzyme in this pathway leads to an increase in reactive oxygen species and a reduction in reduced glutathione. Moreover, knockdown of any component enzyme in this series of reactions also results in a pronounced suppression of PDAC growth in vitro and in vivo. Furthermore, we establish that the reprogramming of glutamine metabolism is mediated by oncogenic KRAS, the signature genetic alteration in PDAC, through the transcriptional upregulation and repression of key metabolic enzymes in this pathway. The essentiality of this pathway in PDAC and the fact that it is dispensable in normal cells may provide novel therapeutic approaches to treat these refractory tumours.

Selective BRAFV600E Inhibition Enhances T-Cell Recognition of Melanoma without Affecting Lymphocyte Function

Targeted therapy against the BRAF/mitogen-activated protein kinase (MAPK) pathway is a promising new therapeutic approach for the treatment of melanoma. Treatment with selective BRAF inhibitors results in a high initial response rate but limited duration of response. To counter this, investigators propose combining this therapy with other targeted agents, addressing the issue of redundancy and signaling through different oncogenic pathways. An alternative approach is combining BRAF/MAPK-targeted agents with immunotherapy. Preliminary evidence suggests that oncogenic BRAF (BRAF(V600E)) contributes to immune escape and that blocking its activity via MAPK pathway inhibition leads to increased expression of melanocyte differentiation antigens (MDA). Recognition of MDAs is a critical component of the immunologic response to melanoma, and several forms of immunotherapy capitalize on this recognition. Among the various approaches to inhibiting BRAF/MAPK, broad MAPK pathway inhibition may have deleterious effects on T lymphocyte function. Here, we corroborate the role of oncogenic BRAF in immune evasion by melanoma cells through suppression of MDAs. We show that inhibition of the MAPK pathway with MAPK/extracellular signal-regulated kinase kinase (MEK) inhibitors or a specific inhibitor of BRAF(V600E) in melanoma cell lines and tumor digests results in increased levels of MDAs, which is associated with improved recognition by antigen-specific T lymphocytes. However, treatment with MEK inhibitors impairs T lymphocyte function, whereas T-cell function is preserved after treatment with a specific inhibitor of BRAF(V600E). These findings suggest that immune evasion of melanomas mediated by oncogenic BRAF may be reversed by targeted BRAF inhibition without compromising T-cell function. These findings have important implications for combined kinase-targeted therapy plus immunotherapy for melanoma.

BRAF Inhibition Is Associated with Enhanced Melanoma Antigen Expression and a More Favorable Tumor Microenvironment in Patients with Metastatic Melanoma

Purpose: To evaluate the effects of BRAF inhibition on the tumor microenvironment in patients with metastatic melanoma. Experimental Design: Thirty-five biopsies were collected from 16 patients with metastatic melanoma pretreatment (day 0) and at 10 to 14 days after initiation of treatment with either BRAF inhibitor alone (vemurafenib) or BRAF + MEK inhibition (dabrafenib + trametinib) and were also taken at time of progression. Biopsies were analyzed for melanoma antigens, T-cell markers, and immunomodulatory cytokines. Results: Treatment with either BRAF inhibitor alone or BRAF + MEK inhibitor was associated with an increased expression of melanoma antigens and an increase in CD8+ T-cell infiltrate. This was also associated with a decrease in immunosuppressive cytokines [interleukin (IL)-6 and IL-8] and an increase in markers of T-cell cytotoxicity. Interestingly, expression of exhaustion markers TIM-3 and PD1 and the immunosuppressive ligand PDL1 was increased on treatment. A decrease in melanoma antigen expression and CD8 T-cell infiltrate was noted at time of progression on BRAF inhibitor alone and was reversed with combined BRAF and MEK inhibition. Conclusions: Together, these data suggest that treatment with BRAF inhibition enhances melanoma antigen expression and facilitates T-cell cytotoxicity and a more favorable tumor microenvironment, providing support for potential synergy of BRAF-targeted therapy and immunotherapy. Interestingly, markers of T-cell exhaustion and the immunosuppressive ligand PDL1 are also increased with BRAF inhibition, further implying that immune checkpoint blockade may be critical in augmenting responses to BRAF-targeted therapy in patients with melanoma. Clin Cancer Res; 19(5); 1225–31. ©2013 AACR.

Perioperative CA19-9 Levels Can Predict Stage and Survival in Patients With Resectable Pancreatic Adenocarcinoma

PURPOSE Different prognostic factors stratify patients with pancreatic adenocarcinoma. The purpose of this study was to determine whether preoperative CA19-9 levels can predict stage of disease or survival and whether a change in preoperative to postoperative CA19-9 or the postoperative CA19-9 predicts overall survival. PATIENTS AND METHODS Four hundred twenty-four consecutive patients with pancreatic adenocarcinoma underwent resection between January 1, 1985 and January 1, 2004. Of the patients with a bilirubin less than 2 mg/dL, 176 had preoperative CA19-9 values, and 111 had pre- and postoperative CA19-9 values. Survival was measured from the first postoperative CA19-9 level measured (median, 39 days) until death or last follow-up. A multivariate failure time model was fit using clinical, operative, pathologic, and adjuvant treatment characteristics, and a categorization was defined by the values and changes in CA19-9 before and after surgery. RESULTS Of the 176 patients, 128 (73%) had T3 lesions, and 99 (56%) had N1 disease; 138 patients (78%) underwent pancreaticoduodenectomy. Median preoperative CA19-9 levels were lower in N0 patients compared with patients with positive nodes (nine v 164 U/mL, respectively; nonparametric P = .06) and in T1/T2 patients versus T3 patients (41 v 162 U/mL, respectively; P = .03). Median follow-up time (n = 111) was 1.8 years (range, 1 to 12.9 years), with overall actuarial 1-, 3-, and 5-year survival rates of 70%, 36%, and 30%, respectively. Significant predictors of survival on multivariate analysis included a decrease in CA19-9 (P = .0005), negative lymph nodes (P = .001), lower T stage (P = .0008), and postoperative CA19-9 less than 200 U/mL (P = .0007). CONCLUSION In patients with pancreatic adenocarcinoma, preoperative CA19-9 correlates with stage of disease. Both a postoperative decrease in CA19-9 and a postoperative CA19-9 value of less than 200 U/mL are strong independent predictors of survival, even after adjusting for stage. CA19-9 levels should be included in a patients perioperative care and should be considered for prognostic nomograms.

Intrahepatic Cholangiocarcinoma: An International Multi-Institutional Analysis of Prognostic Factors and Lymph Node Assessment

PURPOSE To identify factors associated with outcome after surgical management of intrahepatic cholangiocarcinoma (ICC) and examine the impact of lymph node (LN) assessment on survival. PATIENTS AND METHODS From an international multi-institutional database, 449 patients who underwent surgery for ICC between 1973 and 2010 were identified. Clinical and pathologic data were evaluated using uni- and multivariate analyses. RESULTS Median tumor size was 6.5 cm. Most patients had a solitary tumor (73%) and no vascular invasion (69%). Median survival was 27 months, and 5-year survival was 31%. Factors associated with adverse prognosis included positive margin status (hazard ratio [HR], 2.20; P < .001), multiple lesions (HR, 1.80; P = .001), and vascular invasion (HR, 1.59; P = .015). Tumor size was not a prognostic factor (HR, 1.03; P = .23). Patients were stratified using the American Joint Committee on Cancer/International Union Against Cancer T1, T2a, and T2b categories (seventh edition) in a discrete step-wise fashion (P < .001). Lymphadenectomy was performed in 248 patients (55%); 74 of these (30%) had LN metastasis. LN metastasis was associated with worse outcome (median survival: N0, 30 months v N1, 24 months; P = .03). Although patients with no LN metastasis were able to be stratified by tumor number and vascular invasion (N0; P < .001), among patients with N1 disease, multiple tumors and vascular invasion, either alone or together, failed to discriminate patients into discrete prognostic groups (P = .34). CONCLUSION Although tumor size provides no prognostic information, tumor number, vascular invasion, and LN metastasis were associated with survival. N1 status adversely affected overall survival and also influenced the relative effect of tumor number and vascular invasion on prognosis. Lymphadenectomy should be strongly considered for ICC, because up to 30% of patients will have LN metastasis.

Causes, consequences, and remedies for growth-induced solid stress in murine and human tumors

The presence of growth-induced solid stresses in tumors has been suspected for some time, but these stresses were largely estimated using mathematical models. Solid stresses can deform the surrounding tissues and compress intratumoral lymphatic and blood vessels. Compression of lymphatic vessels elevates interstitial fluid pressure, whereas compression of blood vessels reduces blood flow. Reduced blood flow, in turn, leads to hypoxia, which promotes tumor progression, immunosuppression, inflammation, invasion, and metastasis and lowers the efficacy of chemo-, radio-, and immunotherapies. Thus, strategies designed to alleviate solid stress have the potential to improve cancer treatment. However, a lack of methods for measuring solid stress has hindered the development of solid stress-alleviating drugs. Here, we present a simple technique to estimate the growth-induced solid stress accumulated within animal and human tumors, and we show that this stress can be reduced by depleting cancer cells, fibroblasts, collagen, and/or hyaluronan, resulting in improved tumor perfusion. Furthermore, we show that therapeutic depletion of carcinoma-associated fibroblasts with an inhibitor of the sonic hedgehog pathway reduces solid stress, decompresses blood and lymphatic vessels, and increases perfusion. In addition to providing insights into the mechanopathology of tumors, our approach can serve as a rapid screen for stress-reducing and perfusion-enhancing drugs.

Radiological and surgical implications of neoadjuvant treatment with FOLFIRINOX for locally advanced and borderline resectable pancreatic cancer.

PURPOSE On the basis of the ACCORD trial, FOLFIRINOX is effective in metastatic pancreatic adenocarcinoma (PDAC), making it a rational choice for locally advanced PDAC (LA). Aims of this study are to evaluate the accuracy of imaging in determining the resectability of PDAC and to determine the surgical and clinicopathologic outcomes of pancreatic resections after neoadjuvant FOLFIRINOX therapy. PATIENTS AND METHODS Clinicopathologic data were retrospectively collected for surgical PDAC patients receiving neoadjuvant FOLFIRINOX or no neoadjuvant therapy between April 2011 and February 2014. Americas Hepato-Pancreato-Biliary Association/Society of Surgical Oncology/Society for Surgery of the Alimentary Tract consensus guidelines defined LA and borderline. Imaging was reviewed by a blinded senior pancreatic surgeon. RESULTS Of 188 patients undergoing resection for PDAC, 40 LA/borderline received FOLFIRINOX and 87 received no neoadjuvant therapy. FOLFIRINOX resulted in a significant decrease in tumor size, yet 19 patients were still classified as LA and 9 as borderline. Despite post-FOLFIRINOX imaging suggesting continued unresectability, 92% had an R0 resection. When compared with no neoadjuvant therapy, FOLFIRINOX resulted in significantly longer operative times (393 vs 300 minutes) and blood loss (600 vs 400 mL), but significantly lower operative morbidity (36% vs 63%) and no postoperative pancreatic fistulas. Length of stay (6 vs 7 days), readmissions (20% vs 30%), and mortality were equivalent (1% vs 0%). On final pathology, the FOLFIRINOX group had a significant decrease in lymph node positivity (35% vs 79%) and perineural invasion (72% vs 95%). Median follow-up was 11 months with a significant increase in overall survival with FOLFIRINOX. CONCLUSIONS After neoadjuvant FOLFIRINOX imaging no longer predicts unresectability. Traditional pathologic predictors of survival are improved, and morbidity is decreased in comparison to patients with clearly resectable cancers at the time of presentation.

Lymphocytic reaction to colorectal cancer is associated with longer survival, independent of lymph node count, microsatellite instability, and CpG island methylator phenotype.

Purpose: Host immune response to tumor may be an important prognostic factor for colon cancer patients. However, little is known on prognostic significance of histopathologic lymphoid reaction to tumor, independent of the number of lymph nodes examined and tumoral molecular alterations, including microsatellite instability (MSI) and the CpG island methylator phenotype (CIMP), both of which are associated with lymphocytic reaction and clinical outcome. Experimental Design: Using 843 colorectal cancer patients in two independent prospective cohorts, we examined patient prognosis in relation to four components of lymphocytic reaction (i.e., Crohns-like reaction, peritumoral reaction, intratumoral periglandular reaction, and tumor-infiltrating lymphocytes) and overall lymphocytic score (0-12). CIMP was determined using eight markers including CACNA1G, CDKN2A (p16), CRABP1, IGF2, MLH1, NEUROG1, RUNX3, and SOCS1. Cox proportional hazard models computed hazard ratio for mortality, adjusted for covariates including tumor stage, body mass index, lymph node count, KRAS, BRAF, p53, cyclooxygenase-2 (PTGS2), MSI, CIMP, and LINE-1 methylation. Results: Increasing overall lymphocytic reaction score including tumor-infiltrating lymphocytes was associated with a significant improvement in colorectal cancer–specific and overall survival (log-rank P < 0.003). These findings remained significant (adjusted hazard ratio estimates, 0.49-0.71; Ptrend < 0.009) in multivariate models that adjusted for covariates, including body mass index, MSI, CIMP, LINE-1 hypomethylation, and cyclooxygenase-2. The beneficial effect of tumoral lymphocytic reaction was consistent across strata of clinical, pathologic, and molecular characteristics. Conclusions: Lymphocytic reactions to tumor were associated with improved prognosis among colorectal cancer patients, independent of lymph node count and other clinical, pathologic, and molecular characteristics. (Clin Cancer Res 2009;15(20):6412–20)

Transcriptional control of autophagy–lysosome function drives pancreatic cancer metabolism

Activation of cellular stress response pathways to maintain metabolic homeostasis is emerging as a critical growth and survival mechanism in many cancers. The pathogenesis of pancreatic ductal adenocarcinoma (PDA) requires high levels of autophagy, a conserved self-degradative process. However, the regulatory circuits that activate autophagy and reprogram PDA cell metabolism are unknown. Here we show that autophagy induction in PDA occurs as part of a broader transcriptional program that coordinates activation of lysosome biogenesis and function, and nutrient scavenging, mediated by the MiT/TFE family of transcription factors. In human PDA cells, the MiT/TFE proteins—MITF, TFE3 and TFEB—are decoupled from regulatory mechanisms that control their cytoplasmic retention. Increased nuclear import in turn drives the expression of a coherent network of genes that induce high levels of lysosomal catabolic function essential for PDA growth. Unbiased global metabolite profiling reveals that MiT/TFE-dependent autophagy–lysosome activation is specifically required to maintain intracellular amino acid pools. These results identify the MiT/TFE proteins as master regulators of metabolic reprogramming in pancreatic cancer and demonstrate that transcriptional activation of clearance pathways converging on the lysosome is a novel hallmark of aggressive malignancy.Activation of cellular stress response pathways to maintain metabolic homeostasis is emerging as a critical growth and survival mechanism in many cancers1. The pathogenesis of pancreatic ductal adenocarcinoma (PDA) requires high levels of autophagy2–4, a conserved self-degradative process5. However, the regulatory circuits that activate autophagy and reprogram PDA cell metabolism are unknown. We now show that autophagy induction in PDA occurs as part of a broader transcriptional program that coordinates activation of lysosome biogenesis and function, and nutrient scavenging, mediated by the MiT/TFE family transcription factors. In PDA cells, the MiT/TFE proteins6 – MITF, TFE3 and TFEB – are decoupled from regulatory mechanisms that control their cytoplasmic retention. Increased nuclear import in turn drives the expression of a coherent network of genes that induce high levels of lysosomal catabolic function essential for PDA growth. Unbiased global metabolite profiling reveals that MiT/TFE-dependent autophagy-lysosomal activation is specifically required to maintain intracellular amino acid (AA) pools. These results identify the MiT/TFE transcription factors as master regulators of metabolic reprogramming in pancreatic cancer and demonstrate activation of clearance pathways converging on the lysosome as a novel hallmark of aggressive malignancy.

Pancreatic ductal adenocarcinoma: is there a survival difference for R1 resections versus locally advanced unresectable tumors? What is a "true" R0 resection?

Objective:Patients who undergo an R0 resection of their pancreatic ductal adenocarcinoma (PDAC) have an improved survival compared with patients who undergo an R1 resection. It is unclear whether an R1 resection confers a survival benefit over locally advanced (LA) unresectable tumors. Our aim was to compare the survival of patients undergoing an R1 resection with those having LA tumors and to explore the prognostic significance of a 1-mm surgical margin. Methods:Clinicopathologic data from a pancreatic cancer database between January 1993 and July 2008 were reviewed. Locally advanced tumors had no evidence of metastatic disease at exploration. Results:A total of 1705 patients were evaluated for PDAC in the Department of Surgery. Of the 1084 (64%) patients who were surgically explored, 530 (49%) were considered unresectable (286 locally unresectable, 244 with distant metastasis). One hundred fifty-seven (28%) of the resected PDACs had an R1 resection. Patients undergoing an R1 resection had a slightly longer survival compared with those who had locally advanced unresectable cancers (14 vs 11 months; P < 0.001). Patients with R0 resections had a favorable survival compared with those with R1 resections (23 vs 14 months; P < 0.001), but survival after resections with 1-mm margin or less (R0-close) were similar to R1 resections: both groups had a significantly shorter median survival than patients with a margin of greater than 1 mm (R0-wide) (16 vs 14 vs 35 months, respectively; P < 0.001). Conclusions:Patients undergoing an R1 resection still have an improved survival compared with patients with locally advanced unresectable pancreatic adenocarcinoma. R0 resections have an improved survival compared with R1 resections, but this survival benefit is lost when the tumor is within 1 mm of the resection margin.