Abstract 1421: Overexpression of the pro-glycolytic transcription factor MondoA enhances malignant potential of ALL in vivo

Introduction. Most cancer cells use glycolysis for energy production regardless of whether they are under normoxic or hypoxic condition (Koppenol et al., 2011). Warburg described this metabolic hallmark of cancer cells, named aerobic glycolysis. The high dependence of tumor cells on glucose utilization may be exploited for therapeutic intervention. One of the genes, which have effects on glucose metabolism, is MondoA. It is a transcription factor (Stoltzman et al., 2008) highly over-expressed in ALL (Wernicke et al. 2012). MondoA:MLX heterodimers have been discussed as a parallel network to MYC:MAX, which have broad effects on cellular growth, proliferation and survival (Kaadige et al., 2010; Sloan and Ayer, 2010). Knockdown experiments revealed that MondoA impacts on metabolic activity of leukemic cells and their glucose utilization. Furthermore MondoA knockdown resulted in a more differentiated leukemic phenotype and shifted gene expression towards a signature favoring apoptosis and thus reducing the signs of aggressiveness of leukemia cells in vitro (Wernicke et al. 2012). Based on our previous work, we hypothesized that assessing survival of leukemia bearing mice may reveal the role of MondoA in ALL in vivo.

Methods. The murine/human xeno-transplantation model of leukemia was used (Richter et al. 2009). NALM-6 ALL cell lines were transduced by retroviral gene transfer of constructs, harboring specific for MondoA short hairpin RNA (shRNA), and injected into immune deficient Rag2-/-γC-/- mice. The tumor burden were measured and compared to the one in control mice bearing leukemia cells transduced with nonfunctional siRNA. Tumor burden of mice were evaluated by cyto- and histochemistry and by measuring the CD10+ blast cells content in blood, spleen and bone marrow by flow cytometry.

Results. These experiments showed that MondoA knockdown significantly reduced leukemia cells' proliferation in mice as compared to control group. Although signs of leukemia engraftment were observed in all mice, the differences in amount of CD10+ blasts cells in blood, bone marrow and spleens in the controls and in the MondoA knockdown group were significant (p= 0,0079). Experimental results also showed a decrease of the leukemic infiltration-induced swelling of the spleen in the group with MondoA knockdown. Median spleen weight was 0.22g and 0.08g in the control and in the experimental group.

Conclusion. These findings demonstrate that the downregulation of MondoA by RNA interference significantly delays leukemic burden and malignancy of B cell ALL in vivo and further confirm that MondoA is an attractive target for targeted and immune therapy of ALL.

Citation Format: Alexandra A. Sipol, Günther H.S. Richter, Caroline M. Wernicke, Thomas G.P. Grunewald, Stefan Burdach. Overexpression of the pro-glycolytic transcription factor MondoA enhances malignant potential of ALL in vivo. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 1421. doi:10.1158/1538-7445.AM2014-1421

MondoA is highly overexpressed in acute lymphoblastic leukemia cells and modulates their metabolism, differentiation and survival

Acute lymphoblastic leukemia (ALL) is the most common childhood cancer. To identify novel candidates for targeted therapy, we performed a comprehensive transcriptome analysis identifying MondoA (MLXIP) - a transcription factor regulating glycolysis - to be overexpressed in ALL compared to normal tissues. Using microarray-profiling, gene-set enrichment analysis, RNA interference and functional assays we show that MondoA overexpression increases glucose catabolism and maintains a more immature phenotype, which is associated with enhanced survival and clonogenicity of leukemia cells. These data point to an important contribution of MondoA to leukemia aggressiveness and make MondoA a potential candidate for targeted treatment of ALL.

Mesenchymal stromal cells for treatment of steroid-refractory GvHD: a review of the literature and two pediatric cases

Severe acute graft versus host disease (GvHD) is a life-threatening complication after allogeneic hematopoietic stem cell transplantation. Human mesenchymal stromal cells (MSCs) play an important role in endogenous tissue repair and possess strong immune-modulatory properties making them a promising tool for the treatment of steroid-refractory GvHD. To date, a few reports exist on the use of MSCs in treatment of GvHD in children indicating that children tend to respond better than adults, albeit with heterogeneous results.

We here present a review of the literature and the clinical course of two instructive pediatric patients with acute steroid-refractory GvHD after haploidentical stem cell transplantation, which exemplify the beneficial effects of third-party transplanted MSCs in treatment of acute steroid-refractory GvHD. Moreover, we provide a meta-analysis of clinical studies addressing the outcome of patients with steroid-refractory GvHD and treatment with MSCs in adults and in children (n = 183; 122 adults, 61 children). Our meta-analysis demonstrates that the overall response-rate is high (73.8%) and confirms, for the first time, that children indeed respond better to treatment of GvHD with MSCs than adults (complete response 57.4% vs. 45.1%, respectively).

These data emphasize the significance of this therapeutic approach especially in children and indicate that future prospective studies are needed to assess the reasons for the observed differential response-rates in pediatric and adult patients.

[Aorto-intestinal fistula following bypass operation--a rare cause of gastrointestinal hemorrhage]

A rare case of aorto-enteric fistula is reported. The age of the patient was 56 years. The fistula is a complication of abdominal aortic surgery. The early diagnosis (duodenoscopy) decides on life of the patient.