Personalized peptide vaccine-induced immune response associated with long-term survival of a metastatic cholangiocarcinoma patient.

BACKGROUND & AIMS: We report a novel experimental immunotherapeutic approach in a patient with metastatic intrahepatic cholangiocarcinoma. In the 5year course of the disease, the initial tumor mass, two local recurrences and a lung metastasis were surgically removed. Lacking alternative treatment options, aiming at the induction of anti-tumor T cells responses, we initiated a personalized multi-peptide vaccination, based on in-depth analysis of tumor antigens (immunopeptidome) and sequencing. METHODS: Tumors were characterized by immunohistochemistry, next-generation sequencing and mass spectrometry of HLA ligands. RESULTS: Although several tumor-specific neo-epitopes were predicted in silico, none could be validated by mass spectrometry. Instead, a personalized multi-peptide vaccine containing non-mutated tumor-associated epitopes was designed and applied. Immunomonitoring showed vaccine-induced T cell responses to three out of seven peptides administered. The pulmonary metastasis resected after start of vaccination showed strong immune cell infiltration and perforin positivity, in contrast to the previous lesions. The patient remains clinically healthy, without any radiologically detectable tumors since March 2013 and the vaccination is continued. CONCLUSIONS: This remarkable clinical course encourages formal clinical studies on adjuvant personalized peptide vaccination in cholangiocarcinoma. LAY SUMMARY: Metastatic cholangiocarcinomas, cancers that originate from the liver bile ducts, have very limited treatment options and a fatal prognosis. We describe a novel therapeutic approach in such a patient using a personalized multi-peptide vaccine. This vaccine, developed based on the characterization of the patient's tumor, evoked detectable anti-tumor immune responses, associating with long-term tumor-free survival.

Do patient- and tumor-related factors predict the peritoneal spread of pancreatic adenocarcinoma?

PURPOSE: In pancreatic cancer, the presence of peritoneal carcinomatosis (PC) precludes the possibility of a surgical cure, irrespective of the resectability of the primary tumor. However, peritoneal spread cannot be reliably detected radiographically during preoperative tumor staging. METHODS: The pancreatic adenocarcinoma database of the Tübingen Comprehensive Cancer Center included 29 patients in whom PC was incidentally detected during the surgery. These patients were retrospectively compared for patient- and tumor-related factors with 29 randomly selected patients without PC who underwent curative resection. RESULTS: Clinical jaundice and diarrhea were more frequently present in patients without PC. The CA 19-9 levels were significantly higher in patients with PC compared to those in patients without PC. No other differences were observed in the patient- or tumor-related factors between the two groups. CONCLUSION: In pancreatic cancer patients, markedly elevated CA 19-9 levels may serve as surrogate marker for peritoneal dissemination, irrespective of the local resectability of the tumor. In such patients, laparoscopy should be considered as an additional staging tool to rule out peritoneal carcinomatosis.

Induction of tumor stem cell differentiation--novel strategy to overcome therapy resistance in gastric cancer.

PURPOSE: Metastases are a frequent finding in gastric cancer and are associated with poor prognosis. A recently discovered link between metabolic changes, differentiation, and therapy resistance due to tumor stem cells could depict a novel approach in cancer research and therapy. Phosphoglycerate kinase 1 (PGK1) is a metabolic enzyme and is known to be involved in enabling gastric cancer cells to be invasive and to disseminate. In this study, we investigated if PGK1 is a promising candidate in inducing stem cell differentiation in gastric cancer. MATERIALS AND METHODS: MKN45 gastric cancer cells were used due to their known cancer stem cell population, which is defined by the surface marker CD44. MKN45 cells were separated between CD44+ and CD44- cells and, in equal parts, incubated with shRNA anti-PGK1 using fluorescence-activated cell sorting (FACS) analysis; they were then injected into nude mice to evaluate their tumor growth behavior in vivo. Further, the invasive potential of gastric cancer cells was evaluated in vitro using the xCelligence analyzing system. RESULTS: CD44+ gastric cancer cells treated with and without shRNA anti-PGK1 were capable to cause tumor growth in vivo, whereas tumor growth in CD44+ cells treated with shRNA anti-PGK1 was considerably smaller in comparison with that in CD44+ cells without treatment. CD44- cells did not show any noticeable tumor growth in vivo. By targeting PGK1, the invasive potential of gastric cancer cells was impressively reduced in vitro. In all our cells, which were targeted with shRNA anti-PGK1, we did not find any change that is in accordance with the phenotype of the cells using FACS analysis. CONCLUSIONS: Our findings suggest that targeting the key metabolic enzyme PGK1 in gastric cancer cells may open a new chapter in cancer treatment, which is well worth for further exploration in combination with recent chemotherapy, and might be a promising possibility to overcome therapy resistance in gastric cancer.

Lactate influences the gene expression profile of human mesenchymal stem cells (hMSC) in a dose dependant manner.

BACKGROUND/AIMS: Wounds, especially non-healing wounds are characterized by elevated tissue lactate concentrations. Lactate is known for being able to stimulate collagen synthesis and vessel growth. Lately it has been shown that lactate, in vivo, plays an important role in homing of stem cells. With this work we aimed to show the influence of lactate on the gene expressionprofile of human mesenchymal stem cells (hMSC). MATERIALS AND METHODS: hMSCs were obtained from bone marrow and characterized with fluorescence-activated cell sorting (FACS) analysis. Subsequently the hMSCs were treated with either 0, 5, 10 and 15 mM lactate (pH 7,4) for 24 hours. RNA Isolation from stimulated hMSCs and controls was performed. The Microarray analysis was performed using AffymetrixHuGene 1.0 ST Gene Chip. Selected targets were subsequently analysed using quantitative real time PCR (RTq-PCR). RESULTS: We were able to show that lactate in moderate concentrations of 5 respectively 10 mM leads to an anti-inflammatory, anti-apoptotic but growth and proliferation promoting gene expression after 24 h. In contrast, high lactate concentrations of 15 mM leads to the opposed effect, namely promoting inflammation and apoptosis. Hypoxia induced genes did not show any significant regulation. Contrary to expectation, we were not able to show any significant regulation of candidates associated with glycolysis. CONCLUSION: We were able to show that lactate alters gene expression but does not change the cell phenotype, which might be helpful for further investigations of new treatment strategies for chronic non-healing wounds as well as tumor-therapy and neuronal plasticity.

Impact of endotoxin exposure after exhausting exercise on the immune system in solid organ transplant recipients.

Subsequent to prolonged exhausting exercise a transient immunosuppression is often observed in athletes. This so-called "open window" results in a reduced resistance of the athletes to viral and bacterial infections after an exhaustive exercise bout. Concerning the effect of bacterial endotoxin contact after exhausting exercise in transplant recipients, who are innately immunosuppressed by their medication, no data exists at present. After performing 81 km cycling, including ascending more than 1800 m in altitude, peripheral blood from 10 male kidney transplant recipients and from 10 healthy controls matched for age and gender was obtained. Simulating contact of the athletes with a pathogen post-exercise, the blood samples were incubated with Lipopolysaccharides (LPS). Thereafter microarray analysis was performed. Microarray analysis revealed a markedly oppositional pattern of gene expression in transplant recipients compared with their controls after LPS incubation. Especially immune response genes were significantly over-represented in controls immediately after the exhaustive exercise bout with LPS stimulation, whereas numerous apoptotic genes were over-represented in transplant recipients. Merging our previous data with these recent findings it should be discussed if transplant recipients need to reduce their immunosuppressive medication before performing exhaustive exercise.

MSH2 and CXCR4 involvement in malignant VIPoma.

BACKGROUND: Vasoactive intestinal polypeptide secreting tumors(VIPomas) are rare endocrine tumors of the pancreas with an estimated incidence of 0.1 per million per year. The molecular mechanisms that mediate development of VIPomas are poorly investigated and require definition. METHODS: A genome- and gene expression analysis of specimens of a primary pancreatic VIPoma with hepatic metastases was performed. The primary tumor, the metastases, the corresponding healthy tissue of the liver, and the pancreas were compared with each other using oligonucleotide microarrays and loss of heterozygosity (LOH). RESULTS: The results revealed multiple LOH events and several differentially expressed genes. Our finding of LOH and downregulation was conspicuous in the microarray analysis for the mismatch repair gene MSH2 in the primary pancreatic VIPoma tumor, the hepatic metastasis but not in the corresponding healthy tissue. Further a strong overexpression of the chemokine CXCR4 was detected in the hepatic metastases compared to its pancreatic primary. With a review of the literature we describe the molecular insights of metastatic development in VIPoma. CONCLUSION: In VIPoma, defects in the mismatch repair system especially in MSH2 may contribute to carcinogenesis, and increased CXCR4 may be associated with liver metastasis.

The gut is not only the target but a source of inflammatory mediators inhibiting gastrointestinal motility during sepsis.

BACKGROUND: Sepsis is a common problem in intensive care patients leading to multi-organ failure and gastrointestinal paralysis. AIM: The aim of the study was to investigate whether the gastrointestinal tract is not only the target but also the source of inflammatory mediators inhibiting gastrointestinal motility. METHODS: Mesenteric lymph was obtained from rats in which a sepsis was induced by lipopolysaccharide (LPS) intraperitoneally. Gastrointestinal motility was recorded following mesenteric lymph- or TNFα infusion into the jugular vein of separate healthy recipient rats using the strain gauge transducer technique. RESULTS: Infusion of sepsis lymph significantly impairs gastric and colonic motility, decreasing the motility-index in the stomach and colon by about 57% and 21% respectively in comparison to baseline motility. Among other inflammatory mediators, TNFα plays an important role in mediating the inhibitory effect of mesenteric lymph on gastrointestinal motility during sepsis. CONCLUSIONS: The gastrointestinal tract is the source and the target of inflammatory mediators released during sepsis causing paralytic ileus.

Cytostatic activity of the duplex drug linking 2'-deoxy-5-fluorouridine (5FdU) with 3'-C-ethynylcytidine (ECyd) against gastric adenocarcinoma cell lines.

The cytostatic potential of the new duplex drug 2'-deoxy-5-fluorouridylyl-(5'5')-3'-C-ethynylcytidine (5FdU(5'-5')ECyd) was evaluated in comparison to those of 5-fluorouracil (5FU), 2'-deoxy-5-fluorourindine (5FdU), 3'-C-ethynylycytidine (ECyd), cisplatin, an equimolar mixture of 5FdU + ECyd and a three component-mixture of 0.75 µM epirubicin/0.90 µM cisplatin/3.0 µM 5FU (ECF) by incubation of the two human gastric adenocarcinoma cell lines 23132/87 and MKN-45. The molar composition of ECF was taken from data of a triple combination chemotherapy for human gastric cancer. Time and dose depending inhibition of cell growth was determinated using the CASY technology. A growth decrease of both cell lines from 100% to about 20% was observed by treatment with ECF over a course of 14 days. This result provided basis to estimate the cytostatic potential of all tested drugs and combinations thereof. Corresponding high activities in respect to ECF were achieved by incubation of 23132/87 cells with single drugs 49 µM 5FU, 10 µM cisplatin, 3.4 µM 5FdU, 0.65 µM ECyd, the mixture 0.32 µM 5FdU + 0.32 µM ECyd and 0.32 µM 5FdU(5'-5')ECyd. The less sensitive MKN-45 cells require a 1.5-4 fold higher dose of the standard chemotherapeutics in order to achieve an equivalent cytostatic effect, in respect to the 23132/87 cell line,. However, the effect of the duplex drugs on MKN-45 cells was gained with a 5-fold lower dose than ECF. Due to its high cytostatic potential the duplex drug, which covalently links two active anticancer compounds, could be a new therapeutic alternative for chemotherapy in gastric cancer, currently treated with different combinations.

The Over-The-Scope Clip (OTSC) for the treatment of gastrointestinal bleeding, perforations, and fistulas.

BACKGROUND: The Over-The-Scope Clip (OTSC(®)) enables the treatment of patients with gastrointestinal complications such as bleeding, perforations, and fistulas. The aim of this retrospective study was to analyze the therapeutic results of the performed treatments. METHODS: Since April 2006, 50 patients have been treated for different indications with the OTSC clip in our department. Besides hemostasis (n = 27) in the colon and the upper GI tract, the clip has been used for closure of esophageal and gastric perforations and adaptation of covered and free perforations after colonoscopy (n = 11). Furthermore, the OTSC has been used to close fistulas (n = 8) and for preoperative marking (n = 4). RESULTS: The primary treatment was successful in all cases. There were two secondary bleedings that required endoscopic interventions. Closure of iatrogenic perforations of the upper and lower GI tract was successful in all cases. A permanent closure of fistulas could not be achieved in all cases with the OTSC clip. CONCLUSION: The OTSC clip is effective and safe for complicated bleeding and closure of perforations of the gastrointestinal tract. Nevertheless, sufficient closure of chronic fistulas with the OTSC still remains an unsolved problem.

Cytoreductive surgery and HIPEC in peritoneal recurrent ovarian cancer: experience and lessons learned.

PURPOSE: Peritoneal recurrence of ovarian cancer is frequent after primary surgery and chemotherapy and has poor long-term survival. De novo cytoreductive surgery is crucial with the potential to improve prognosis, especially when combined with hyperthermic intraperitoneal chemotherapy (HIPEC). METHODS: The sampled data of 40 consecutive patients were retrospectively analyzed. Thirty-one patients were treated with cytoreductive surgery combined with hyperthermic intraperitoneal chemotherapy. RESULTS: No patient was lost in the perioperative period, and the combined procedure was performed with acceptable morbidity. Colon-preserving cytoreductive surgery was associated with reduced morbidity. CONCLUSIONS: Patients suffering from peritoneal recurrence of ovarian cancer should be considered for radical reoperation with HIPEC in a center with expertise in multimodal therapeutic options. Organ-preserving cytoreductive surgery allows complete cytoreduction with the goal of decreasing morbidity.

Phosphoglycerate kinase 1 a promoting enzyme for peritoneal dissemination in gastric cancer.

Peritoneal carcinomatosis is a frequent finding in gastric cancer associated with a poor prognosis. The features that enable gastric tumors to disseminate are poorly understood until now. Previously, we showed elevated mRNA levels of phosphoglycerate kinase 1 (PGK1), an adenosine triphosphate-generating enzyme in the glycolytic pathway, the chemokine receptor 4 (CXCR4), the corresponding chemokine ligand 12 (CXCL12) and beta-catenin in specimens from gastric cancer patients with peritoneal carcinomatosis. In this study, the influence of PGK1 on CXCR4 and beta-catenin was assessed as well as the invasiveness of PGK1 overexpressing cancer cells. In this current study, we found that PGK1 regulates the expression of CXCR4 and beta-catenin at the mRNA and protein levels. On the other hand, CXCR4 regulates the expression of PGK1. Plasmid-mediated overexpression of PGK1 dramatically increased the invasiveness of gastric cancer cells. Interestingly, inhibition of CXCR4 in cells overexpressing PGK1 produced only a moderate reduction of invasiveness suggesting that, PGK1 itself has a critical role in tumor invasiveness. Immunohistochemistry in specimens from diffuse gastric cancer patients also revealed an overexpression of PGK1 in patients with development of peritoneal carcinomatosis. Therefore, PGK1 may be a crucial enzyme in peritoneal dissemination. Together these findings suggest that the enhanced expression of PGK1 and its signaling targets CXCR4 and beta-catenin in gastric cancer cells promote peritoneal carcinomatosis. Thus, PGK1 may serve as prognostic marker and/or be a potential therapeutic target to prevent dissemination of gastric carcinoma cells into the peritoneum.

Circadian expression of clock- and tumor suppressor genes in human oral mucosa.

PURPOSE: Circadian rhythms are daily oscillations of multiple biological processes driven by endogenous clocks. Imbalance of these rhythms has been associated with cancerogenesis in humans. To further elucidate the role circadian clocks have in cellular growth control, tumor suppression and cancer treatment, it is revealing to know how clock genes and clock-controlled genes are regulated in healthy humans. MATERIALS AND METHODS: Therefore comparative microarray analyses were conducted investigating the relative mRNA expression of clock genes throughout a 24-hour period in cell samples obtained from oral mucosa of eight healthy diurnally active male study participants. Differentially expressed selected genes of interest were additionally evaluated using qRT-PCR. RESULTS: Microarray analysis revealed 33 significant differentially regulated clock genes and clock- controlled genes, throughout a one day period (6.00h, 12.00h, 18.00h, 24.00h). Hereof were 16 clock genes and 17 clock- controlled genes including tumor suppressor- and oncogenes. qRT-PCR of selected genes of interest, such as hPER2, hCRY1, hBMAL1, hCCRN4L and hSMAD5 revealed significant circadian regulations. CONCLUSION: Our study revealed a proper circadian regulation profile of several clock- and tumor suppressor genes at defined points in time in the participants studied. These findings could provide important information regarding genes displaying the same expression profile in the gastrointestinal tract amounting to a physiological expression profile of healthy humans. In the future asynchronous regulations of those genes might be an additional assistant method to detect derivations distinguishing normal from malignant tissue or assessing risk factors for cancer.

Phosphoglycerate kinase 1 promoting tumor progression and metastasis in gastric cancer - detected in a tumor mouse model using positron emission tomography/magnetic resonance imaging.

BACKGROUND/AIMS: Tumor dissemination is frequent in gastric cancer and implies a poor prognosis. Cure is only achievable provided an accurate staging is performed at primary diagnosis. In previous studies we were able to show a relevant impact of increased phosphoglycerate kinase 1 expression (PGK1; a glycolytic enzyme) on invasive properties of gastric cancer in-vivo and in-vitro. Thus the aim of the present study was to evaluate the effect of enhanced PGK1 expression in gastric cancer employing magnetic resonance (MR)-imaging combined with positron emission tomography (PET), a recently emerging new high resolution imaging technique in a mouse model. METHODS: A metastatic nude mouse model simulating human gastric cancer behavior by orthotopic tumor implantation was established. Mice were divided into one control group (n=5) and two experimental groups (n=30) divided by half in animals baring tumors from MKN45-cells and MKN45-cells with plasmid-mediated overexpression of PGK1. In the course of tumor growth MR-imaging and PET/MRI fusion was performed. Successively experimental animals were examined macroscopically and histopathologically regarding growth, metastasis and PGK1 expression. RESULTS: Elevated PGK1 expression increased invasive and metastatic behavior of implanted gastric tumors significantly. MR/PET- imaging results in-vivoand subsequent ex-vivo findings concerning tumor growth and metastasis correlated excellently and could be underlined by concordant immuohistochemical PGK1 staining. CONCLUSION: Consistent in-vivo findings suggest that PGK1 might be crucially involved in gastric malignancy regarding growth and metastasis, which was also underlined by novel imaging techniques. Thus, PGK1 may be exploited as a prognostic marker and/or be of potential therapeutic value preventing malignant dissemination.

Influence of exhaustive exercise on the immune system in solid organ transplant recipients.

Prolonged exhaustive exercise has a great impact on the immune system of athletes and leads to a transient weakening of the immune system. A host of studies has documented changes of immune parameters in peripheral blood following exercise. Concerning the effect of exhaustive exercise in transplant recipients there is little knowledge at present. We analysed peripheral blood in healthy athletes and transplant recipients who participated in the "Euregio cycling tour 2009" before and immediately after they performed 81 km of cycling that included ascending more than 1800 m in altitude. A full blood count and an automated differential count as well as microarray analysis were performed before, immediately after and one day after exercise in 10 male patients carrying a kidney transplant and in 10 controls matched in age and gender. Comparing the absolute increase in neutrophils in these two groups, we detected that the relative increase in neutrophils was significantly smaller in transplant recipients compared to their corresponding controls after exhaustive exercise. While both groups were comparable in performance, microarray analysis revealed a markedly different pattern of gene expression in transplant recipients compared to their controls. From the 130 genes that were significantly upregulated in controls immediately after exercise, only 12 genes were also upregulated in transplant recipients. 64 different genes were upregulated in transplant recipients only. Our findings may be related to the immunosuppressive medication that the transplant recipients took and therefore it should also be discussed that regular exercise might reduce the need for immunosuppressive medication in transplant recipients.

A pancreas-preserving technique for the management of symptomatic pancreatic anastomotic insufficiency refractory to conservative treatment after pancreas head resection.

BACKGROUND AND AIM: Management of symptomatic pancreatic anastomotic insufficiency after pancreas head resection remains controversial. Completion pancreatectomy as one frequently performed option is associated with poor prognosis. PATIENTS AND METHODS: During a 4-year period, a two-step strategy was applied in four consecutive patients suffering from pancreatic anastomotic insufficiency refractory to conservative management after a pancreas head resection. In the first step, sepsis was overbridged by meticulous debridement and resection of the pancreaticojejunostomy, leaving the biliary anastomosis untouched, and selective drainage of the pancreatic duct as well as the peripancreatic area. In the second step, after recovery, the procedure was completed with a novel pancreaticojejunostomy. RESULTS: The surgical procedure was completed in three patients after a mean of 164 (range: 112-213) days. One patient died from cardiac arrest 54 days after the reoperation with resolved abdominal sepsis. No pancreatic anastomotic insufficiency occurred after the new pancreaticojejunostomy had been performed. Three patients are alive and tumor-free with normal exocrine and endocrine pancreatic function after a mean follow-up of 20.3 (3-38) months following the definitive reconstruction. CONCLUSION: The two-step pancreas-preserving strategy can be used as an alternative to completion pancreatectomy for patients suffering from severe pancreatic anastomotic insufficiency.

shRNA-mediated inhibition of PhosphoGlycerate Kinase 1 (PGK1) enhances cytotoxicity of intraperitoneal chemotherapy in peritoneal metastasis of gastric origin.

BACKGROUND: Phosphoglycerate kinase 1 (PGK1) plays metabolic, kinase and translational roles in Peritoneal metastasis (PM) of gastric origin and is associated with chemoresistance. Silencing PGK1 might potentiate the effect of chemotherapy. METHODS: In an orthoptic xenograft nude mice model, human gastric cancer cells (MKN45) were grown in 22 donor animals. Solid tumors were then grafted into the gastric subserosa of 102 recipient animals and allowed to grow for 10 days. Animals were randomized into 7 groups: Five test groups: 1) Mitomycin C (MMC), 2) MMC and small hairpin RNA silencing of PGK1 with an adenoviral vector (Adv-shPGK1), 3) 5-fluorouracil (5-FU), 4) 5-FU and Adv-shPGK1, 5) Adv-shPGK1 alone; two control groups: 1) Sham (NaCl 0.9%), 2) empty viral vector. Intraperitoneal therapy was administered on postoperative day (POD) 11 and 18. Animals were sacrificed at POD 21, analysis was blinded to therapy. RESULTS: Adding Adv-shPGK1 to 5-FU reduced the number (0.23 ± 0.43 vs. 1.36 ± 1.00, p = 0.005) and weight (0,005 ± 0.012 mg vs. 0.05 ± 0.08 mg, p = 0.002) of PM as compared to 5-FU alone. The effect of adding Adv-shPGK1 to MMC did not reach statistical significance. Mortality was not increased by adding Adv-shPGK1 to chemotherapy but was increased by Adv-shPGK1 alone as compared to sham. CONCLUSION: In this experimental model, combined therapy with chemotherapy and Adv-shPGK1 improves control of PM of gastric origin as compared to chemotherapy alone and might counteract chemoresistance of PM. A systemic toxicity of Adv-shPGK1 cannot be excluded.

Local peritonectomy highly attracts free floating intraperitoneal colorectal tumour cells in a rat model.

BACKGROUND/AIMS: Intraperitoneal free cancer cells are associated with a higher risk of recurrence and a poorer prognosis in colorectal surgery. Tumour recurrence may occur early after surgery. One potential mechanism is the ability of peritoneal lesions to attract tumour cells. METHODS: In Wag-Rija rats, the parietal peritoneum was resected on a defined area, a corresponding control area was marked in the same rat and colorectal tumour cells (CC531) were applied into the abdomen after surgery. Tissue was harvested 6 or 9 days after surgery to evaluate intra-abdominal tumour growth. Additionally tumour cells were applied 2 weeks after peritoneal resection to investigate tumour growth in a healed area of peritonectomy. Specimens were evaluated for macroscopic tumour spread, weight of the abdominal wall and maximal tumour thickness. RESULTS: Macroscopic tumour spread, weight of the abdominal wall and maximal tumour thickness were significantly increased within the area of peritonectomy after both 6 and 9 days compared to the control area. However, only macroscopic tumour expansion was significantly increased in the healed area of peritonectomy. CONCLUSION: Peritoneal defects may play an important role in the pathogenesis of tumour implantation and might have some impact on tumour recurrence. The peritoneal damage should be kept as low as possible.

IDO1 and IDO2 are expressed in human tumors: levo- but not dextro-1-methyl tryptophan inhibits tryptophan catabolism.

OBJECTIVES: Indoleamine-2,3-Dioxygenase (IDO) is an immunosuppressive molecule inducible in various cells. In addition to classic IDO (IDO1), a new variant, IDO2, has recently been described. When expressed in dendritic cells (DCs) or cancer cells, IDO was thought to suppress the immune response to tumors. A novel therapeutic approach in cancer envisages inhibition of IDO with 1-methyl-tryptophan (1MT). The levo-isoform (L-1MT) blocks IDO1, whereas dextro-1MT (D-1MT), which is used in clinical trials, inhibits IDO2. Here we analyze IDO2 expression in human cancer cells and the impact of both 1-MT isoforms on IDO activity. METHODS: Surgically extirpated human primary tumors as well as human cancer cell lines were tested for IDO1 and IDO2 expression by RT-PCR. IDO1 activity of Hela cells was blocked by transfection with IDO1-specific siRNA and analysed for tryptophan degradation by RP-HPLC. The impact of D-1MT and L-1MT on IDO activity of Hela cells and protein isolates of human colon cancer were studied. RESULTS: Human primary gastric, colon and renal cell carcinomas constitutively expressed both, IDO1 and IDO2 mRNA, whereas cancer cells lines had to be induced to by Interferon-gamma (IFN-gamma). Treatment of Hela cells with IDO1-specific siRNA resulted in complete abrogation of tryptophan degradation. Only L-1MT, and not D-1MT, was able to block IDO activity in IFN-gamma-treated Hela cells as well as in protein isolates of primary human colon cancer. CONCLUSIONS: Although IDO2 is expressed in human tumors, tryptophan degradation is entirely provided by IDO1. Importantly, D-1MT does not inhibit the IDO activity of malignant cells. If ongoing clinical studies show a therapeutic effect of D-1MT, this cannot be attributed to inhibition of IDO in tumor cells.

Response to preoperative therapy in upper gastrointestinal cancers.

BACKGROUND: In cancer, a response to therapy implies a reduction in the volume or activity of localized and/or metastatic tumors. In localized upper gastrointestinal cancer, there is no accepted definition of clinical response; however, tumor shrinkage is frequently observed when preoperative therapy is administered. As patients with upper gastrointestinal cancers often undergo multimodal therapy, it is therefore imperative that new definitions for assessing the response to preoperative therapy be established. METHODS: We reviewed the development of response criteria from a historical perspective, with particular emphasis on the criteria used to assess upper gastrointestinal cancers. RESULTS: Observing the response to preoperative therapy appears to make it possible to distinguish between favorable and unfavorable clinical biology in the cancer. Patients who experience a response to preoperative treatment appear to fare better in terms of overall survival than those whose cancers do not respond. We reviewed the published results regarding the response to preoperative therapy and the implications of this for patients. CONCLUSIONS: This review of the literature suggests that a variety of tools are available for defining the response to preoperative therapy and that these need to be exploited. Developing reliable methods of assessing the response will improve the individualization of therapy for patients with gastroesophageal cancer. There is a strong need for surrogate markers for efficacy in order to assess responses that are capable of predicting patient outcome.