Protein arginine methyltransferase 3-induced metabolic reprogramming is a vulnerable target of pancreatic cancer.

BACKGROUND: The biological function of protein arginine methyltransferase 3 (PRMT3) is not well known because very few physiological substrates of this methyltransferase have been identified to date. METHODS: The clinical significance of PRMT3 in pancreatic cancer was studied by database analysis. The PRMT3 protein level of human pancreatic tumors was detected by immunoblotting and immunohistochemical staining. PRMT3-associated proteins and the methylation sites on the proteins were investigated using mass spectrometry. Seahorse Bioscience analyzed the metabolic reprogramming. Combination index analysis and xenograft animal model were conducted to explore the effects of combination of inhibitors of glyceraldehyde-3-phosphate dehydrogenase (GAPDH) and oxidative phosphorylation on tumor growth. RESULTS: We found that the expression of PRMT3 is upregulated in pancreatic cancer, and its expression is associated with poor survival. We identified GAPDH as a PRMT3-binding protein and demonstrated that GAPDH is methylated at R248 by PRMT3 in vivo. The methylation of GAPDH by PRMT3 enhanced its catalytic activity while the mutation of R248 abolished the effect. In cells, PRMT3 overexpression triggered metabolic reprogramming and enhanced glycolysis and mitochondrial respiration simultaneously in a GAPDH-dependent manner. PRMT3-overexpressing cancer cells were addicted to GAPDH-mediated metabolism and sensitive to the inhibition of GAPDH and mitochondrial respiration. The combination of inhibitors of GAPDH and oxidative phosphorylation induced a synergistic inhibition on cellular growth in vitro and in vivo. CONCLUSION: Our results suggest that PRMT3 mediates metabolic reprogramming and cellular proliferation through methylating R248 of GAPDH, and double blockade of GAPDH and mitochondrial respiration could be a novel strategy for the treatment of PRMT3-overexpressing pancreatic cancer.

The learning curve of laparoscopic liver resection after the Louisville statement 2008: Will it be more effective and smooth?

BACKGROUND: Laparoscopic liver resection (LLR) has been proven to be feasible and safe. However, it is a difficult and complex procedure with a steep learning curve. The aim of this study was to evaluate the learning curve of LLR at our institutions since 2008. METHODS: One hundred and twenty-six consecutive LLRs were included from May 2008 to December 2014. Patient characteristics, operative data, and surgical outcomes were collected prospectively and analyzed. RESULTS: The median tumor size was 25 mm (range 5-90 mm), and 96 % of the resected tumors were malignant. 41.3 % (52/126) of patients had pathologically proven liver cirrhosis. The median operation time was 216 min (range 40-602 min) with a median blood loss of 100 ml (range 20-2300 ml). The median length of hospital stay was 4 days (range 2-10 days). Six major postoperative complications occurred in this series, and there was no 90-day postoperative mortality. Regarding the incidence of major operative events including operation time longer than 300 min, perioperative blood loss above 500 ml, and major postoperative complications, the learning curve [as evaluated by the cumulative sum (CUSUM) technique] showed its first reverse after 22 cases. The indication of laparoscopic resection in this series extended after 60 cases to include tumors located in difficult locations (segments 4a, 7, 8) and major hepatectomy. CUSUM showed that the incidence of major operative events proceeded to increase again, and the second reverse was noted after an additional 40 cases of experience. Location of the tumor in a difficult area emerged as a significant predictor of major operative events. CONCLUSIONS: In carefully selected patients, CUSUM analysis showed 22 cases were needed to overcome the learning curve for minor LLR.

Plasmalemmal Vesicle Associated Protein (PLVAP) as a therapeutic target for treatment of hepatocellular carcinoma.

BACKGROUND: Hepatocellular carcinoma (HCC) is a malignancy with poor survival outcome. New treatment options for the disease are needed. In this study, we identified and evaluated tumor vascular PLVAP as a therapeutic target for treatment of HCC. METHODS: Genes showing extreme differential expression between paired human HCC and adjacent non-tumorous liver tissue were investigated. PLVAP was identified as one of such genes with potential to serve as a therapeutic target for treatment of HCC. A recombinant monoclonal anti-PLVAP Fab fragment co-expressing extracellular domain of human tissue factor (TF) was developed. The potential therapeutic effect and toxicity to treat HCC were studied using a Hep3B HCC xenograft model in SCID mice. RESULTS: PLVAP was identified as a gene specifically expressed in vascular endothelial cells of HCC but not in non-tumorous liver tissues. This finding was confirmed by RT-PCR analysis of micro-dissected cells and immunohistochemical staining of tissue sections. Infusion of recombinant monoclonal anti-PLVAP Fab-TF into the main tumor feeding artery induced tumor vascular thrombosis and extensive tumor necrosis at doses between 2.5 µg and 12 µg. Tumor growth was suppressed for 40 days after a single treatment. Systemic administration did not induce tumor necrosis. Little systemic toxicity was noted for this therapeutic agent. CONCLUSIONS: The results of this study suggest that anti-PLVAP Fab-TF may be used to treat HCC cases for which transcatheter arterial chemoembolization (TACE) is currently used and potentially avoid the drawback of high viscosity of chemoembolic emulsion for TACE to improve therapeutic outcome. Anti-PLVAP Fab-TF may become a viable therapeutic agent in patients with advanced disease and compromised liver function.

Histopathologic correlation of hepatocellular carcinoma after transcatheter arterial chemoembolization with polyvinyl alcohol particle of various sizes.

AIM: Transcatheter arterial chemoembolization (TACE) is one of major treatment for unresectable hepatocellular carcinomas (HCC) and has been used as a neoadjuvant treatment before surgery. This study was to describe the histopathologic features of HCC after TACE with variously sized polyvinyl alcohol (PVA) particles. MATERIALS AND METHODS: Seventeen patients undergoing TACE with PVA followed by surgery for HCC were analyzed. The PVA particles used in TACE were categorized into two groups in respects of particle sizes: the group I, 47-90 µm (n=8) and the group II, >90-250 µm (n=9). The histopathologic features of the resected HCC were characterized with the emphasis on the number of thrombosed vessels and minimal diameter of arterioles/capillaries containing polyvinyl alcohol particles. The clinical results after TACE were also addressed. RESULTS: Histopathologic examinations showed that the median minimal diameters of arterioles containing PVA particles were 0.035 mm in group I and 0.06 mm in group II (p=0.0078). We observed the PVA particle in the sinusoidal spaces of non-tumourous liver in only one patient. However, no sinusoidal infarction was demonstrated in either group. Mean tumour necrosis rate was 67% vs. 61% for the group I and II, respectively. CONCLUSIONS: The smaller PVA particles can reach and occlude more distal arteriolar capillaries, but rarely leak into non-tumourous hepatic sinusoidal spaces. Slightly better tumour necrosis rate after TACE can be achieved.

Risk factors associated with conversion from nonmalignant to malignant diagnosis after surgical excision of breast papillary lesions.

PURPOSE: Management of papillary lesions of the breast identified during preoperative tissue diagnosis remains controversial. This study was designed to analyze the clinical factors associated with under-diagnosis of malignancy in breast papillary lesions. METHODS: Patients with a preoperative tissue diagnosis of benign or atypical papillary lesions, who received surgical excision between 1991 and 2005, were identified. Age of diagnosis, family history of breast cancer, presentation of nipple discharge, palpable mass, mammogram grading, size of lesion, and final pathological diagnosis were analyzed. Tissue sections were reviewed to confirm the diagnosis of malignancy and reasons of discrepancy. RESULTS: A total of 205 women with 228 papillary lesions were studied. The median age was 42 (range, 12-83) years. Malignancies were diagnosed after surgery in 21 cases (9.2%). Patients aged 45 years or older and atypical lesions according to fine needle aspiration cytology (FNAC) or core needle biopsy (CNB) were associated with higher risk for postoperative malignant diagnosis with P values of 0.0008 and < 0.0001, respectively. Pathology review of 19 lesions with malignancy revealed that reasons for preoperative nonmalignant diagnosis were borderline lesions in nine (47.3%), sampling problem in six (31.5%), interpretation error in three (15.7%) and uninterpretable sample in one (5.2%). CONCLUSIONS: In this cohort, 9.21% of preoperative nonmalignant papillary lesions were converted to malignant diagnosis after surgery. Atypical lesions and patients aged 45 years or older were significant factors associated with such conversion. Surgical excision should be considered for papillary lesions of breast, especially for patients with the identified risk factors.

Isolated limb infusion for in-transit malignant melanoma of the extremity: a well-tolerated but less effective alternative to hyperthermic isolated limb perfusion.

BACKGROUND: Isolated limb infusion (ILI) is a recently described minimally invasive technique developed in Australia for delivering regional chemotherapy. This study examined the efficacy and toxicity of ILI, compared to hyperthermic isolated limb perfusion (HILP), in treating extremity in-transit melanoma. METHODS: Variables from a prospective single institution database of 120 regionally treated melanoma patients (1995-2007) were compared using chi-square analysis. This included 61 consecutive ILI treatments in 58 patients and 59 HILP treatments in 54 patients. Response was defined at 3 months using the response evaluation criteria in solid tumors (RECIST). ILI was performed using melphalan (LPAM) and dactinomycin for 30 min after limb temperature reached 37 degrees C. HILP was performed using LPAM for 60 min after limb temperature reached 38.5 degrees C. RESULTS: For ILI (n = 61), the complete response (CR) rate was 30%, the partial response (PR) rate was 14%, and there was no response (NR) in 56% of patients. The median duration of CR was 12 months and 18% of patients experienced (grade >or=3) toxicity. HILP (n = 59) was associated with a better (P < 0.001) response rate (CR 57%, PR 31%, and NR 12%) however, more patients (32%) experienced grade >or=3 toxicity (P = 0.037). The dose of LPAM was corrected for ideal body weight (IBW) in 40 out of 61 ILI procedures, and 13 of 59 HILP procedures. This dosing modification was associated with decreased toxicity (P = 0.024) without diminishing response. CONCLUSION: ILI was found to be a well-tolerated alternative to HILP. While ILI does not appear to be as effective as HILP, it does seem to be associated with less morbidity.

A unique pancreatic tumor with exclusive hepatocytic differentiation.

Only 7 cases of pancreatic tumor with hepatocytic differentiation have been reported in the literature, including 6 cases of hepatoid carcinoma and one case of hepatoid adenoma. Diagnosis of hepatoid carcinoma depends on recognition of characteristic histological features, supported by other evidence linked to hepatic lineage including alpha-fetoprotein production, positive immunoreactivity to liver synthesized proteins, and in situ hybridization detection of albumin mRNA. In addition, a synchronous focus of carcinoma arising in pancreatic ducts, islet cells, or acinar cells is essential. We report a unique case of pancreatic tumor with exclusive hepatocytic differentiation. In this tumor, we were unable to find a synchronous focus of carcinoma arising in pancreatic ducts, islet cells, or acinar cells, ruling out the possibility of its being hepatoid carcinoma. Long term follow-up can help to determine whether this tumor is benign or malignant. The patterns of reticulin staining and immunohistochemical staining are suggestive of malignancy, but mitotic activity is low and nuclear pleomorphism is minimal.

Modulation of chemotherapy resistance in regional therapy: a novel therapeutic approach to advanced extremity melanoma using intra-arterial temozolomide in combination with systemic O6-benzylguanine.

This study investigated whether the therapeutic index of regional melanoma therapy using parenteral temozolomide could be improved by chemomodulation with O6-benzylguanine (O6BG), an inhibitor of the DNA repair enzyme O6-alkylguanine-DNA alkyltransferase (AGT). Using a nude rat s.c. human melanoma xenograft model of the extremity, tumors were analyzed for AGT level 2 to 3 hours after the i.p. injection of 3.5 to 70.0 mg/kg O6BG to inhibit AGT activity. Survival studies were conducted using animals that were treated with a 15-minute isolated limb infusion with 10% DMSO in PBS (control), temozolomide alone, or temozolomide in conjunction with single or multiple doses of i.p. O6BG. Tumor volume and toxicity level were monitored every other day. Administration of 3.5 mg/kg O6BG depleted tumor AGT activity by 93.5% (P < 0.01). Groups treated with regional temozolomide alone (350 mg/kg), systemic temozolomide with O6BG, or vehicle combined with O6BG showed no significant tumor responses compared with controls. Whereas use of regional temozolomide alone at a higher dose (750 mg/kg) showed some degree of tumor response, regional temozolomide given in conjunction with multiple dosages of O6BG showed a marked (P < 0.01) reduction in tumor growth with minimal toxicity. Our findings suggest that AGT modulation by the administration of O6BG in combination with temozolomide regional chemotherapy leads to a significant improvement in melanoma antitumor responses. Clinical trials using chemotherapy modulation may improve response rates in future regional infusion and perfusion drug trials.

Effect of neoadjuvant chemoradiation on operative mortality and morbidity for pancreaticoduodenectomy.

BACKGROUND: Neoadjuvant chemoradiotherapy (neo-CRT) is being used with increasing frequency for periampullary tumors, but how it alters the complication rate of pancreaticoduodenectomy (PD) is unclear. METHODS: A retrospective analysis was conducted of 79 patients with periampullary malignancies who received 5-fluorouracil-based neo-CRT followed by PD. RESULTS: There was no difference in mortality between PD after neo-CRT (3.8%) and conventional PD for either malignant (4.5%) or benign (2.2%) disease. Focusing only on patients with malignancy, the neo-CRT group had a significantly lower pancreatic leak rate than the conventional group (10% vs. 43%; P < .001). Intra-abdominal abscesses were less common in the neo-CRT group (8.8% vs. 21%; P = .019), and there was one (1.2%) amylase-rich abscess in neo-CRT group, compared with eight (12%) in the conventional group. In addition, two patients in the conventional group died of leak-associated sepsis, compared with none in the neo-CRT group. Multivariate analysis revealed that neoadjuvant chemoradiation (odds ratio, .15) was the most significant factor associated with a reduced risk of pancreatic leak. CONCLUSIONS: Neo-CRT does not increase the mortality or morbidity of PD. In contrast, neo-CRT was associated with a marked reduction in the incidence of pancreatic leak, as well as leak-associated morbidity and mortality.

Predictors of outcome after hyperthermic isolated limb perfusion: role of tumor response.

HYPOTHESIS: Analysis of multiple clinical and pathological factors in patients undergoing therapeutic hyperthermic isolated limb perfusion for extremity melanoma can identify variables with prognostic significance. DESIGN: Retrospective review of a prospectively collected limb perfusion database with a median follow-up interval of 32.2 months. SETTING: Single-institution tertiary care surgical oncology unit. PATIENTS: We report a series of 59 consecutive therapeutic hyperthermic isolated limb perfusion treatments (14 upper extremity and 45 lower extremity) in 54 patients with melanoma from January 1, 1995, through December 31, 2002, using a standard melphalan dosing protocol. At the time of perfusion, 31 cases had fewer than 10 lesions, with none greater than 3 cm in diameter. The remaining 28 cases had 10 or more lesions or at least 1 lesion greater than 3 cm in diameter. MAIN OUTCOME MEASURES: Response, recurrence, and survival were assessed in relation to multiple demographic, clinical, and technical variables using chi2, log-rank, and Kaplan-Meier survival analyses. RESULTS: The 3-year survival for the entire cohort was 54%. Thirty-three (56%) of the 59 perfusion treatments resulted in a persistent complete response of at least 6 months' duration. Statistical analysis showed that patients with no evidence of regional nodal involvement had a significantly lower incidence of distant recurrence (P = .02). Those patients achieving a complete response to therapy had a survival advantage (P = .03). CONCLUSION: In patients undergoing therapeutic hyperthermic isolated limb perfusion for in-transit melanoma, the ability to achieve a complete response following treatment, independent of regional nodal status, was the strongest predictor of long-term survival.

The role of hyperthermia in regional alkylating agent chemotherapy.

The role of hyperthermia during regional alkylating agent chemotherapy is controversial. The aim of this study was to determine the exact contribution of hyperthermia to tumor response during isolated limb infusion with l-phenylalanine mustard. Rats bearing rodent fibrosarcoma on the hindlimb underwent isolated limb infusion with saline, saline plus heat, l-phenylalanine mustard, l-phenylalanine mustard under conditions of normothermia, or l-phenylalanine mustard plus hyperthermia. Heat was administered locally using an in-line hot water circulation loop. Treatment with l-phenylalanine mustard at a concentration of 15 or 50 micrograms/mL was ineffective at producing tumor growth delay (P = 0.24 and 0.41, respectively). Furthermore, thermal enhancement of l-phenylalanine mustard activity was not seen at 15 micrograms/mL. However, administration of high-dose l-phenylalanine mustard, 50 micrograms/mL, with increasing amounts of heat yielded increasing tumor growth delay, increased regressions, and decreased proliferative index. Although l-phenylalanine mustard infusion under normothermia yielded a tumor growth delay of 7.1 days, combination l-phenylalanine mustard + hyperthermia treatment produced tumor growth delay of 27.0 days (P < 0.01; with two of five animals showing a complete response). Four hours after isolated limb infusion, 50.9% of cells in tumor treated with l-phenylalanine mustard + hyperthermia experienced apoptosis, whereas only 18.1, 16, and 4.4% of cells underwent apoptosis after treatment with l-phenylalanine mustard, saline + hyperthermia, or saline. The mean concentration of l-phenylalanine mustard within tumor relative to perfusate following isolated limb infusion was found to be similar among all groups at 0.023, 0.025, and 0.032 in animals undergoing isolated limb infusion with l-phenylalanine mustard, l-phenylalanine mustard + normothermia, and l-phenylalanine mustard + hyperthermia, respectively. These data indicate a synergistic cytotoxic effect of l-phenylalanine mustard + hyperthermia in isolated limb infusion, which is not attributable to enhanced tumor drug uptake.

Modulation of resistance to regional chemotherapy in the extremity melanoma model.

BACKGROUND: The presence of resistance to chemotherapy is associated with poor tumor response and patient survival in a variety of tumors. Attempts to modulate resistance in conjunction with systemic chemotherapy have been limited by the toxicity of combined therapy, particularly gastrointestinal or hematopoetic toxicity. This study explored systemic modulation of resistance in conjunction with intra-arterial regional therapy to determine if tumor responses to melphalan could be improved with acceptable toxicity. METHODS: Using a nude rat human xenograft model of extremity melanoma,we analyzed tumors for glutathione (GSH), the main protein in the melphalan resistance pathway. Modulation of GSH was performed with intraperitoneal buthionine sulfoximine (BSO). In parallel, BSO-modulated and nonmodulated animals underwent survival studies after regional intra-arterial perfusion with melphalan or saline. Rats were monitored daily for tumor growth and toxicity. RESULTS: BSO depleted tumor GSH levels by 71.8% with minimal toxicity. Survival studies using increasing melphalan concentrations demonstrated similar tumor growth. The combined use of modulator and chemotherapeutic agent showed a significant tumor growth delay as compared to control and drug-alone group without enhanced toxicity. CONCLUSIONS: Modulation of resistance in conjunction with regional chemotherapy allows for improved tumor responses with minimal toxicity. These results demonstrate that BSO can potentiate the cytotoxic effects of regional melphalan therapy in the setting of extremity melanoma.

In-transit melanoma: the role of alkylating-agent resistance in regional therapy.

BACKGROUND: Regional perfusion treatments for melanoma, using the alkylating agent melphalan, show variable responses in magnitude and duration. Surprisingly, the potential contribution of alkylating-agent resistance mechanisms to diminish tumor responses, especially the crucial cellular detoxifying system formed by glutathione (GSH) and its associated enzyme glutathione-S-transferase (GST), has remained unexplored. Objectives of this study were to characterize GSH levels and GST activity in melanoma of patients undergoing regional perfusion and examine the effect of melphalan concentration in both an in vitro human melanoma cell line and in the extremity melanoma of an in vivo rodent limb infusion model. STUDY DESIGN: Human in-transit melanoma, muscle, subcutaneous tissue, and skin (n = 9) and metastatic regional lymph nodes (n = 7) were evaluated for GSH level and GST activity. Effects of increasing melphalan exposure on GSH and GST were studied in an in vitro human melanoma cell line. A survival human melanoma xenograft model of isolated limb infusion using increasing dosages of melphalan was used, with evaluation of GSH and GST in the recurrent tumor. RESULTS: GSH levels in human in-transit lesions and muscle were significantly higher than that of skin and subcutaneous tissue. Four of 9 patients had tumor-to-muscle GSH ratio > 1. A strong correlation was seen between in vitro melphalan dose and resultant GSH level and GST activity. In vivo recurrent tumor GSH levels correlated with increasing melphalan infusion dose. CONCLUSIONS: A GSH-based resistance pathway may play a role in effecting response and toxicity to regional melphalan perfusion.

Intrahepatic cholangiocarcinoma with lymphoepithelioma-like carcinoma component.

We report an unusual case of intrahepatic cholangiocarcinoma (ICC) with lymphoepithelioma-like carcinoma (LELC) component in a 60-yr-old woman who was found incidentally to have an abdominal mass. Histologically, the tumor showed 2 distinct patterns with dense lymphoplasma cell infiltration. The first pattern, comprising approximately 20% of total tumor volume, showed the features of lymphoepithelioma-like carcinoma, as commonly found in nasopharyngeal carcinoma (NPC). The second pattern was a moderately differentiated cholangiocarcinoma. In situ hybridization for Epstein-Barr virus (EBV)-encoded RNA (EBER) showed positive nuclear labeling of tumor cells in both patterns, but not in surrounding inflammatory cells. By the polymerase chain reaction, the latent membrane protein gene (LMP-1) in this case was shown to have a 30 bp deletion in the C-terminus, a unique feature in high prevalence areas of undifferentiated nasopharyngeal carcinoma, such as in Taiwan. Presence of the EBV genomes and their expression in the cholangiocarcinoma cells suggested that EBV may play an important role in the pathogenesis of ICC with LELC. In this case, it is unclear why only 20% of the glands were transformed into LELC. The mechanism whereby EBV transforms the malignant glands into the distinct morphology resembling NPC warrants further investigation.

Induction of anti-melanoma CTL response using DC transfected with mutated mRNA encoding full-length Melan-A/MART-1 antigen with an A27L amino acid substitution.

Modification of the parental immunodominant Melan-A/MART-1 peptide (MART-1(26-35)) by replacing the alanine with leucine (A27L) enhances its immunogenicity. Because of the reported advantages of RNA over peptides in DC vaccines, we sought to mutate the MART-1 gene to encode a full-length MART-1 antigen with an A27L amino acid substitution. Human DC were transfected with A27L-mutated MART-1 RNA (A27L RNA) or native MART-1 RNA, and then used to stimulate autologous T cells from a series of 8 HLA-A2+ volunteers. After three stimulations, all CTL induced with DC/A27L RNA exhibited more tetramer+ cells, and demonstrated stronger antigen-specific IFNgamma-secreting activity compared to CTL induced with DC/native RNA. A potent MART-1-specific, and predominantly class-I-restricted lysis was detected in most CTL induced with DC/A27L RNA, while native RNA-induced CTL showed minimal and non-specific lysis. HLA-A2+ DC and MART-1 negative/A2+ melanoma cells transfected with the A27L RNA were recognized and killed by MART-1-specific CTL, suggesting that these APC efficiently processed the A27L RNA and presented correct MART-1-specific epitope(s). In summary, introducing an A27L mutation into the MART-1 full-length mRNA sequence enhanced the immunogenicity of the encoded MART-1 Ag. The ease with which such a mutation can be made in RNA presents another potential advantage of using RNA for immunotherapy. Our results support considering this strategy for enhancing the immunogenicity of DC-based RNA vaccines.

Marked variability of melphalan plasma drug levels during regional hyperthermic isolated limb perfusion.

BACKGROUND: Hyperthermic isolated limb perfusion (HILP) with melphalan as treatment for locally recurrent or in-transit malignant melanoma is frequently performed but the principle for calculating drug dosage remains poorly understood. METHODS: This study examined the pharmacokinetic profile of 14 consecutive patients to determine what variables were associated with toxicity and tumor responses. RESULTS: Marked fourfold variability was noted in patient plasma melphalan concentrations. We defined a factor--the ratio of estimated limb volume (Vesti) to melphalan volume of distribution (Vss), Vesti/Vss--that was much more strongly correlated with acute regional toxicity than either area under concentration-time curve or peak plasma concentration. In addition, we found that AUX2 was the best correlate of tumor response. CONCLUSIONS: Pharmacokinetic evaluation of prospective HILP trials is critical to not only understand response and toxicity outcomes but also to potentially improve the therapeutic index of regional perfusion.