Cancer-associated fibroblast-derived acetate promotes pancreatic cancer development by altering polyamine metabolism via the ACSS2-SP1-SAT1 axis

The ability of tumour cells to thrive in harsh microenvironments depends on the utilization of nutrients available in the milieu. Here we show that pancreatic cancer-associated fibroblasts (CAFs) regulate tumour cell metabolism through the secretion of acetate, which can be blocked by silencing ATP citrate lyase (ACLY) in CAFs. We further show that acetyl-CoA synthetase short-chain family member 2 (ACSS2) channels the exogenous acetate to regulate the dynamic cancer epigenome and transcriptome, thereby facilitating cancer cell survival in an acidic microenvironment. Comparative H3K27ac ChIP-seq and RNA-seq analyses revealed alterations in polyamine homeostasis through regulation of SAT1 gene expression and enrichment of the SP1-responsive signature. We identified acetate/ACSS2-mediated acetylation of SP1 at the lysine 19 residue that increased SP1 protein stability and transcriptional activity. Genetic or pharmacologic inhibition of the ACSS2-SP1-SAT1 axis diminished the tumour burden in mouse models. These results reveal that the metabolic flexibility imparted by the stroma-derived acetate enabled cancer cell survival under acidosis via the ACSS2-SP1-SAT1 axis.

Disruption of FDPS/Rac1 axis radiosensitizes pancreatic ductal adenocarcinoma by attenuating DNA damage response and immunosuppressive signalling

Background

Radiation therapy (RT) has a suboptimal effect in patients with pancreatic ductal adenocarcinoma (PDAC) due to intrinsic and acquired radioresistance (RR). Comprehensive bioinformatics and microarray analysis revealed that cholesterol biosynthesis (CBS) is involved in the RR of PDAC. We now tested the inhibition of the CBS pathway enzyme, farnesyl diphosphate synthase (FDPS), by zoledronic acid (Zol) to enhance radiation and activate immune cells.

Methods

We investigated the role of FDPS in PDAC RR using the following methods: in vitro cell-based assay, immunohistochemistry, immunofluorescence, immunoblot, cell-based cholesterol assay, RNA sequencing, tumouroids (KPC-murine and PDAC patient-derived), orthotopic models, and PDAC patient's clinical study.

Findings

FDPS overexpression in PDAC tissues and cells (P < 0.01 and P < 0.05) is associated with poor RT response and survival (P = 0.024). CRISPR/Cas9 and pharmacological inhibition (Zol) of FDPS in human and mouse syngeneic PDAC cells in conjunction with RT conferred higher PDAC radiosensitivity in vitro (P < 0.05, P < 0.01, and P < 0.001) and in vivo (P < 0.05). Interestingly, murine (P = 0.01) and human (P = 0.0159) tumouroids treated with Zol+RT showed a significant growth reduction. Mechanistically, RNA-Seq analysis of the PDAC xenografts and patients-PBMCs revealed that Zol exerts radiosensitization by affecting Rac1 and Rho prenylation, thereby modulating DNA damage and radiation response signalling along with improved systemic immune cells activation. An ongoing phase I/II trial (NCT03073785) showed improved failure-free survival (FFS), enhanced immune cell activation, and decreased microenvironment-related genes upon Zol+RT treatment.

Interpretation

Our findings suggest that FDPS is a novel radiosensitization target for PDAC therapy. This study also provides a rationale to utilize Zol as a potential radiosensitizer and as an immunomodulator in PDAC and other cancers.

Funding

National Institutes of Health (P50, P01, and R01).

Management of early hepatocellular carcinoma: results of the Delphi consensus process of the Americas Hepato-Pancreato-Biliary Association

BACKGROUND

There are many potential treatment options for patients with early stage hepatocellular carcinoma (HCC) and practice patterns vary widely. This project aimed to use a Delphi conference to generate consensus regarding the management of small resectable HCC.

METHODS

A base case was established with review by members of AHPBA Research Committee. The Delphi panel of experts reviewed the literature and scored clinical case statements to identify areas of agreement and disagreement. Following initial scoring, discussion was undertaken, questions were amended, and scoring was repeated. This cycle was repeated until no further likelihood of reaching consensus existed.

RESULTS

The panel achieved agreement or disagreement consensus regarding 27 statements. The overarching themes included that resection, ablation, transplantation, or any locoregional therapy as a bridge to transplant were all appropriate modalities for early or recurrent HCC. For larger lesions, consensus was reached that radiofrequency ablation and microwave ablation were not appropriate treatments.

CONCLUSION

Using a validated system for identifying consensus, an expert panel agreed that multiple treatment modalities are appropriate for early stage HCC. These consensus guidelines are intended to help guide physicians through treatment modalities for early HCC; however, clinical decisions should continue to be made on a patient-specific basis.

Methodological considerations for the design and implementation of a fully longitudinal mixed methods study

Growing interest is evident in longitudinal mixed methods research, particularly fully longitudinal mixed methods designs in which both quantitative and qualitative data are collected concurrently for the duration of the study. Fully longitudinal mixed methods designs are particularly relevant for research on dynamic phenomena because of their ability to illuminate both quantitative and qualitative dimensions of change in real time as the phenomenon of interest changes. However, these are complex research designs and their data-intense nature makes them potentially burdensome for study participants, challenging for research teams, and costly for funding agencies. Despite growing use, the methodological literature on fully longitudinal mixed methods research is sparse and little guidance is available for researchers considering this approach. We address this gap by describing our experience with the design and implementation of a fully longitudinal mixed methods study of a dynamic phenomenon, namely, family caregiving during cancer treatment. We describe important questions and key decisions confronted while developing the research proposal, proactive strategies for study implementation, and implementation realities encountered while the study was in progress. On the basis of insights gained through real-world experience, we offer three guiding principles for researchers undertaking such a study. First, align the study design with the nature of the dynamics in the phenomenon of interest. Second, plan from the start when and how the integration of the longitudinal quantitative and qualitative data will occur. Third, employ implementation strategies that take into account the practical aspects of repeated contacts with study participants for an extended period.

Cellular Phenotypes in Cancer Patient Spleen and Peripheral Blood

Adoptive cellular therapy (ACT) has progressed; however, it remains ineffective for most solid tumors. Further, neoadjuvant patients frequently lack tumor tissue sufficient to isolate and expand tumor infiltrating lymphocytes (TIL’s) that are the primary source of T-cells for ACT. However, patients with tumors near the splenic vasculature often undergo a splenectomy, providing a cellular resource for ACT. We document herein that spleens provide a high frequency and number of CD8+ T-cells, with low expression of exhaustion markers (program death ligand-1 (PD-1), T-cell immunoglobulin and mucin domain containing-3 (TIM-3), and lymphocyte activation gene-3 (LAG-3)) relative to the peripheral blood (PB). The memory phenotypes of these CD8+ T-cells (predominantly central and transitional) support their potential for expansion and their high frequency of PD-1 expression indicates tumor specificity as PD-1, is a surrogate for tumor specificity. Further, spleens have a low frequency of myeloid derived suppressor cells (MDSCs) subsets vs. patient PB. Our preliminary studies with spleens from 19 abdominal tumor patients revealed that the spleens, relative to the PB from the same patients, have a significantly higher frequency of CD8+ and PD-1+CD8+ T-cells, including central and transitional memory T-cells. Further, the CD8+PD-1+ T-cells in the spleen also have a low expression of TIM-3 and LAG-3 suggesting minimal exhaustion as supported by ELISPOT analysis of tumor specific CD8+ T-cells responses. Based on our studies we suggest that resected spleens from cancer patients including pancreatic ductal adenocarcinoma (PDAC) patients can provide a valuable source for ACT due to their high frequency of CD8+PD-1+ T-cells.

Abstract 4049: Cellular phenotypes of spleen cells in cancer patients targeted for adoptive cellular therapy

The spleen is a rich resource of large numbers of lymphocytes, with potential for use in adoptive cellular therapy (ACT). This is of particular relevance to patients with a distal pancreatic ductal adenocarcinoma (PDAC) who frequently undergo a pancreatectomy that required a splenectomy to clear the nodal basin. In this study we compared the phenotypes of eight paired sets of peripheral blood (PB) and spleen cell populations to assess the frequency of myeloid derived suppressor cells (MDSC) and lymphocyte subpopulations. Because a positive clinical response to ACT requires a low frequency of T-regs and MDSC’s, both systemically and in the tumor microenvironment these cells were one of the foci for our studies. A high frequency of these cells negatively correlate with survival and positively with tumor burden. Indeed, in this study we observed a significant decrease in the frequency of granulocytic, monocytic and immature MDSC’s in the spleen vs PB (4.8±1.6 vs. 54.4±6.1; 0.2±0.1 vs. 0.9±0.4; and 0.6±0.1 vs. 2.3±0.8 percent respectively) but not T-regulatory (T-reg) cells (0.8+0.5 vs. 0.1+0.04 percent) supporting the potential superiority of spleen cells relative to PB as a cellular source for ACT. In addition to a significantly higher number of spleen cells as compared to the PB for expansion/infusion, spleens have a higher frequency of T-cells as compared to the PB including CD3+ (35+5 vs. 16+4%), CD4+ (19+2 vs. 10+2%) and CD8+ (10+1 vs. 5+2%) T-cells. The frequency of transitional memory (Ttm) T-cells, which have a high proliferative potential were also significantly increased in the spleen vs. PB (37.5±6 vs. 26±3.0%) as was the frequency of PD1+CD8+ T-cells (8+2 vs 1+0.5%), which have been shown to have tumor specific cytotoxicity in cancer patients. In summary the increased frequency of PD-1+CD8+ cells, a Ttm memory phenotype and low levels of an exhaustion phenotype (TIM3 and Lag3 expression) in spleen cells vs the PB is supportive of the potential utility of these cells for expansion and therapeutic utility for these cells.

Citation Format: Kathryn Cole, Quan Ly, Jesse L. Cox, Michael A. Hollingsworth, James C. Padussis, Jason M. Foster, Luciano M. Vargas, James E. Talmadge. Cellular phenotypes of spleen cells in cancer patients targeted for adoptive cellular therapy [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 4049.

Frequency of Myeloid Derived Suppressor Cells in Spleen and Peripheral Blood from Cancer Patients

The peripheral blood (PB) of cancer patients is frequently neutrophilic and lymphopenic with few studies focused on tissue immunity. In this study we examined eight paired sets of PB and spleen populations to assess the frequency and sub-populations of myeloid derived suppressor- (MDSC) and T-cells. These studies observed a significant decrease in the frequency of granulocytic (G), monocytic (M) and immature MDSC’s in the spleen vs PB (4.8±1.6 vs. 54.4±6.1; 0.2±0.1 vs. 0.9±0.4; and 0.6±0.1 vs. 2.3±0.8 % respectively) but not T-regulatory cells (0.8±0.5 vs. 0.1±0.04 percent). The difference in the G vs M MDSC was consistent with arginase and nitric oxide synthase expression. In contrast, the % of splenic T-cells was increased relative to the PB including CD3+ (35±5 vs. 16±4%), CD4+ (19±2 vs. 10±2%) and CD8+ (10±1 vs. 5±2%). The frequency of transitional memory T-cells (Ttm) was significantly higher in the spleen vs. PB (37.5±6 vs. 26±3.0%) as was the frequency of PD1+CD8+ T-cells (8±2 vs 1±0.5% respectively). The increase in Ttm with their heightened proliferation, effector potential and tumor specific cytotoxicity of PD1+CD8+ cells support the superiority of spleen vs PB cells for adoptive cellular therapy. In support of this both the PD1+ cells were LAG3− and TIM3−, and thus not exhausted. In summary, the spleen cells of cancer patients have an increase in tumor specific effector cells with proliferative potential supporting their utility in therapeutic protocols.

SAT-121 Immediate Dysglycemia After Pancreatic Resection: Prevalence and Risk Factors

Introduction: Postoperative hyper- and hypoglycemia are associated with increased morbidity and mortality following many types of surgical procedures. Long-term development of diabetes mellitus (DM) following pancreatic resection is well documented; however, less is known regarding glycemic control in the immediate postoperative period for patients undergoing pancreatic resection. Methods: We conducted a retrospective study investigating rates of hyperglycemia (blood glucose >140 mg/dL) and hypoglycemia (blood glucose ≤ 70 mg/dL) and associated risk factors in the 10-day postoperative period in patients undergoing pancreatic resection. Patients that underwent pancreaticoduodenectomy (PD), distal pancreatectomy (DP), or complete pancreatectomy (CP) from 7/1/12-7/1/18 were included. Patients with a functional tumor, end-stage renal disease, liver failure, deceased within 14 days of surgery, and solid-organ transplant recipients were excluded. Results: After applying exclusion criteria, 227 of 261 patients were included. Median age was 61 years and 50.2% were male. Preoperative DM was present in 46/227 (20.3%). A total of 130 patients (57.3%) had a pancreatic primary indication for surgery, with other abdominal malignancies accounting for most of the non-pancreatic indications. Most underwent DP (59.5%) followed by PD (40.1%) and CP (0.6%). A total of 162 (71.4%) patients had at least one hyperglycemic episode with 83 (36.6%) having a blood glucose >180 mg/dl. The type of surgical procedure was not a risk factor for hyperglycemia, even when stratified for pancreatic vs non-pancreatic indication. Rates of hyperglycemia were higher in patients with pancreatic cancer (78.5%) compared to those with a non-malignant pancreatic lesion (44.0%), p <0.05. A preoperative diagnosis of DM (p <0.01) and use of TPN or enteral feeds (p <0.01) were risk factors for having any hyperglycemic episode and a hyperglycemic episode >180 mg/dL. Peri-operative steroids and BMI were not associated with hyperglycemia. A total of 46 patients (20.3%) had at least one hypoglycemic episode, including 20 of 105 patients who received insulin. Hypoglycemia risk was higher in patients with BMI < 25 kg/m² compared to BMI >= 25 kg/m² (p <0.01). Most hypoglycemic episodes happened within 3 days postoperatively (73.0%) and while the patient’s diet order was NPO or ice chips without nutritional supplements (63.5%). Renal function was not associated with risk of hypoglycemia. Conclusions: Hyper- and hypoglycemia are both common after pancreatic resection. Hyperglycemia is especially common in patients with pancreatic cancer, preoperative DM, and/or on supplemental nutrition. Hypoglycemia after pancreatic resection may be largely explained by nutritional status. Understanding risk factors for hyper- and hypoglycemia can assist in targeted methods to reduce rates of dysglycemia after pancreatic resection.

National trends in discharge disposition after hepatic resection for malignancy

BACKGROUND

There is a paucity of data on the trends in discharge disposition for patients undergoing hepatic resection for malignancy.

AIM

To analyse the national trends in discharge disposition after hepatic resection for malignancy.

METHODS

The National Inpatient Sample (NIS) database was queried (1993 to 2005) to identify patients that underwent hepatic resection for malignancy and analyse the discharge status (home, home health or rehabilitation/skilled facility).

RESULTS

A weighted total of 74,520 patients underwent hepatic resection of whom, 53,770 patients had a principal diagnosis of malignancy. The overall mortality improved from 6.3% to 3.4%. After excluding patients that died in the post-operative period and those with incomplete discharge status, 45,583 patients were included. The proportion of patients that had acute care needs preventing them from being discharged home without assistance increased from 10.9% in 1993 to 19.5% in 2005. While there was an increase in the number of patients discharged to home health care during this time (8.9% to 13.8%), there was a larger increase in the proportion of patients that were discharged to a rehabilitation or skilled nursing facility (2% to 5.7%). Despite a decrease in the mortality rates, there was no improvement in rate of patients discharged home without assistance over the period of the study.

CONCLUSIONS

The results of the present study demonstrate that after hepatic resection, a significant proportion of patients will need assistance upon discharge. This information needs to be included in patient counselling during pre-operative risk and benefit assessment.

Survival outcomes in node-negative breast cancer patients evaluated with complete axillary node dissection versus sentinel lymph node biopsy

BACKGROUND

Sentinel lymph node (SLN) biopsy combined with microstaging-associated immunohistochemical staining for cytokeratin more accurately assigns patients to their corresponding diagnostic stage. The purpose of this study was to compare the survival outcomes of node-negative patients who received an SLN biopsy with historical control data of node-negative patients who received routine complete axillary lymph node dissection (CALND) in the pre-SLN biopsy era.

METHODS

Under institutional review board approval, 2458 node-negative invasive breast cancer patients between the ages of 25 and 94 years (mean, 60 years) were treated at our institution from January 1986 to May 2004. Of these 2458 patients, 604 (25%) were evaluated with CALND, whereas 1854 (75%) were evaluated with SLN biopsy. All were treated according to the current stage-specific guidelines. Kaplan-Meier graphs of overall survival and disease-free survival were constructed for each group of patients, and the two groups were compared by using the log-rank test.

RESULTS

Overall survival and disease-free survival for the CALND and SLN biopsy groups did not differ significantly (P = .98). The average number of lymph nodes extracted in the pre-SLN biopsy group was 18, whereas the average number of SLNs extracted in the post-SLN biopsy group was 3.

CONCLUSIONS

The survival rate among node-negative breast cancer patients who received an SLN biopsy alone has proven to have no significant difference (P = .98) from the survival rate among node-negative patients who received a CALND. SLN biopsy alone should replace CALND as the primary tool for axillary staging of breast cancer in node-negative patients.

Pancreatic intraductal ultrasonography (IDUS) allows early diagnosis of pancreatic carcinoma in situ: a case report

A 66-year-old woman was admitted with diarrhea, weight loss, slight recurrent abdominal pain, and raised serum amylase and lipase. Lactose intolerance was diagnosed, and treatment was begun. The symptoms diminished. However, slight back pain and elevated serum amylase and lipase levels persisted. A pancreatic tumor was then suspected. Ultrasound, spiral computed tomography (CT), magnetic resonance imaging (MRI), and magnetic resonance cholangiopancreatography (MRCP) examinations were inconclusive. Endoscopic retrograde cholangiopancreatography (ERCP) showed a slight narrowing of the pancreatic duct within the pancreatic body, and endoscopic ultrasound (EUS) revealed a 10 mm intrapancreatic lesion. Finally, intraductal ultrasonography (IDUS) reliably identified a small pancreatic tumor. The tumor was resected, and histology confirmed a well-differentiated adenocarcinoma in situ (UICC stage 0, TisN0M0). This case shows that using high-resolution imaging techniques such as EUS plus IDUS, small malignant pancreatic lesions can be detected at an early stage, when curative action is possible.

Role of laparoscopy in hepatic cyst surgery

BACKGROUND

Hepatic cysts are detected incidentally in 2.5-5% of the population. Only about 15% of such cysts are symptomatic. Since laparoscopic deroofing for liver cysts was first described in 1991 there have been a number of reports of successful laparoscopic management of hepatic cysts, including the laparoscopic management of complex and parasitic cysts.

METHODS

A systematic review of English-language articles on the subject appearing in journals through May 2002 was conducted using the Medline database.

RESULTS

Only a minority of cystic liver lesions need treatment, and the therapeutic approach is guided by the type of cyst. Laparoscopic deroofing (combined with omentoplasty and/or oversewing) of uncomplicated liver cysts is associated with a recurrence rate of 10-25%, with less morbidity and mortality as compared to open surgery. On the other hand, treatment of complex liver cysts and hydatid cysts by laparoscopy is not considered a standard approach.

CONCLUSION

The laparoscopic approach in uncomplicated but symptomatic liver cysts is effective, with low morbidity and mortality. Additional omentoplasty or oversewing appears to reduce the recurrence rate.

Further characterization of IgE-binding antigens in horse dander, with particular emphasis on glycoprotein allergens

IgE-binding components in an extract of horse dander were analyzed, especially with regard to the glycoprotein allergens. After SDS-PAGE under reducing conditions and blotting, several of the glycoprotein IgE-binding components, including two distinct bands of 27 and 31 kDa, were detected. Together with several other bands, they were shown to bind to the lectins Sambucus nigra agglutinin (SNA) and Datura stramonium agglutinin (DSA), indicating terminal sialic acid linked alpha 2 --> 6 to galactose, and galactose linked beta 1 --> 4 to N-acetylglucosamine, respectively. Carbohydrate analysis after SDS-PAGE and blotting showed the presence of mannose, galactose, N-acetylglucosamine, and N-acetyl neuraminic acid in the 27-kDa band. The 14.4-kDa glycoprotein component lost its IgE-binding activity after periodate oxidation. Minor differences in allergenic activity in the other glycoprotein allergenic components were also detected, indicating that the carbohydrate part of the molecule seems to play a role in the IgE-binding activity. Two-dimensional electrophoresis and subsequent immunoblotting were performed to estimate the approximate number, molecular mass, and pI of IgE-binding components. This resulted in a cluster of such components on the blot membrane.