Derek Zieker

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

ObjectivesIndoleamine-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.MethodsSurgically 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.ResultsHuman 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-γ). 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-γ-treated Hela cells as well as in protein isolates of primary human colon cancer.ConclusionsAlthough 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.

Differential gene expression in peripheral blood of patients suffering from post-traumatic stress disorder

Differential gene expression in peripheral blood of patients suffering from post-traumatic stress disorder

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 β‐catenin in specimens from gastric cancer patients with peritoneal carcinomatosis. In this study, the influence of PGK1 on CXCR4 and β‐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 β‐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 β‐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.

PGK1 a potential marker for peritoneal dissemination in gastric cancer.

Background/Aims: Peritoneal carcinomatosis, which is caused by the dissemination of cancer cells into the abdominal cavity is a frequent finding in patients with primary gastric cancer, and it is associated with a poor prognosis. The mechanisms that mediate peritoneal carcinomatosis in diffuse primary gastric tumours require definition. Methods: We therefore compared the gene expression profile in diffuse primary gastric cancer patients with and without peritoneal carcinomatosis (n=13). Human specimens from consecutive gastric cancer patients with and without peritoneal carcinomatosis were investigated using oligonucleotide microarrays. Differentially expressed genes of interest were further evaluated using quantitative real-time polymerase chain reaction (qRT-PCR). Results: The results reveal a significant overexpression of phosphoglycerate kinase 1 (PGK1), the chemokine CXCR4 and its ligand CXCL12 in specimens from diffuse gastric cancer patients with peritoneal carcinomatosis. Overexpression of PGK1 is known to increase the expression of CXCR4. CXCR4 on its part can increase CXCL12 expression. Elevated levels of CXCR4 and CXCL12 are associated with an increase in the metastatic rate and play an important role in the metastatic homing of malignant cells. Conclusion: The overexpression of PGK1 and its signalling targets may be a expression-pathway in diffuse primary gastric carcinomas promoting peritoneal dissemination and may function as prognostic markers and/or be potential therapeutic targets to prevent the migration of gastric carcinoma cells into the peritoneum.

Response to preoperative therapy in upper gastrointestinal cancers

BackgroundIn 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.MethodsWe reviewed the development of response criteria from a historical perspective, with particular emphasis on the criteria used to assess upper gastrointestinal cancers.ResultsObserving 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.ConclusionsThis 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.

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.

Impact of risk factors for prolonged operative time in laparoscopic cholecystectomy.

Objective Laparoscopic cholecystectomy (LC) remains one of the most frequent surgical therapies for symptomatic gallstone disorders. Prolonged operative time is frequently associated with increased complication rates. The aim of this study was to identify the risk factors for prolonged operative times to minimize perioperative morbidity and optimize clinical management. Methods A total of 677 consecutive patients underwent LC. The exclusion criteria were conversion to an open procedure, intraoperative cholangiography, and liver cirrhosis (n=81). Data were analyzed retrospectively with respect to age, sex, BMI, ASA score, previous abdominal surgery, preoperative endoscopic retrograde cholangiopancreatography, acute cholecystitis, and surgeon’s experience. Univariate and multivariate analyses were performed. Results A total of 596 patients, mean (±SD) age of 52.2±16.7 years, were analyzed. In all, 29% of the patients were obese (BMI≥30 kg/m2); 11% had ASA III. Five percent of patients had undergone previous upper abdominal surgery. Overall, 105/596 patients had an acute cholecystitis. Residents of general surgery performed 58% of all operations. The median operative time was 80 min (range, 15–281 min). No statistical significance was found between intraoperative and postoperative complications by surgeon’s experience. Statistically, independent preoperative predictors for prolonged operative time as identified through multivariate analysis were acute cholecystitis, obesity, previous upper abdominal surgery, male sex, and low degree of surgical expertise. Conclusion The risk for prolonged operative times in LC can be assessed on the basis of patients’ characteristics. Assessment of these factors not only helps to optimize the individual outcome for each patient but also improves the decision process toward operative training for junior surgeons.

Phosphoglycerate kinase 1 as a promoter of metastasis in colon cancer

Oxidative stress due to intratumoral hypoxia in solid cancer has been shown to be associated with increased mortality. Phosphoglycerate kinase 1 (PGK1) is an enzyme of the glycolytic pathway, which is regulated by hypoxia-inducible factor-1α (HIF-1α) and has been described for its role in tumor progression and metastasis in several malignancies. We investigated whether the expression of PGK1 varies between metastatic and non-metastatic colon cancer. We compared PGK1 expression in colon cancer patients either with or without metastasis via polymerase chain reaction (PCR) and immunohistochemistry. Microarray analysis was performed to test altered gene expression after PGK1 silencing, using isolates from HCT116 cell lines. PCR results showed an increased expression of PGK1 in colon cancer tissue from metastatic patients in comparison to patients with no metastasis (fold change 2.6, p<0.001). Immunohistochemical staining of PGK1 showed stronger staining in metastatic tissue in comparison to non-metastatic cancer tissue according to a semi-quantitative evaluation. Microarray and subsequent pathway analysis provided 4 genes of interest (CYR61, FOS, JUN and EGR1) used for pathway proposal. The results indicate that increased expression of PGK1 in colon cancer tissue is associated with metastasis. Furthermore, we propose several genes induced by PGK1 that could account for cell migration, mainly EGR1 and CYR61 together with the transcription factors FOS and JUN.

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.

Simultaneous adrenal and extra-adrenal myelolipoma – an uncommon incident: case report and review of the literature

BackgroundExtra-adrenal myelolipomas are rare benign tumours. Other soft tissue tumours such as well-differentiated liposarcomas appear morphological almost identical. Preoperative imaging and especially biopsy are important tools to diagnose these lesions.Case presentationWe report a very seldom case of a simultaneous myelolipoma of the adrenal gland in association with an extra-adrenal myelolipoma in an 75-year-old man. With a review of the literature we describe and discuss the aetiology, differential diagnosis and treatment of patients with respect to adrenal and extra-adrenal lesions.ConclusionThe appearance of a simultaneous adrenal and extra-adrenal myelolipoma is a rare incident. We conclude that such lesions should be considered in the differential diagnosis of a fat-containing tumour in the retroperitoneal tissue/compartment.