Prognostic Values And In Virto Studies Of Transcription Factor GATA3 In Peripheral T Cell Lymphoma

BACKGROUND AND PURPOSE:The peripheral T cell lymphomas (PTCLs) are a group of heterogeneous aggressive non-Hodgkin’s lymphomas (NHLs) associated with poor outcome. Currently standard treatment modality is lacking. Searching for new molcular biomarkers is of great importance for unveiling its mechanism and investigating new drugs. In recent years, international studies based high-throughput gene expression profile revealed that TH2 differentiation marker GATA3 may play an important role in PTCL development. Our study aims to evaluate GATA3 for its prognostic values and explore its effects on tumor proliferation, invasion and other malignant behaviors, in order to provide new evidences for the mechanisms underlying lymphoma pathogenesis.METHODS:This retrospective study included previously untreated patients diagnosed with PTCL in the pathology system at Peking Union Medical College Hospital from January 2007 to December 2013. Formalin-fixed, paraffin-embedded blocks of these patients were collected. Expression of GATA3, TBX21 and CD68 was examined immunohistochemically. Their correlation with outcome was analyzed. For in vitro studies, a stable GATA3-knockdown Hut78 cell line was established by lentivirus transfection. The apoptosis pattern was analyzed through flow cytometry analysis. The expression of various cytokines was semi-quantified by quantitative real-time PCR. The effect of GATA3-knockdown cell line on macrophage differentiation was analyzed by conditioned culture technique.RESULTS:This study included 109 PTCL patients, including 60 PTCL-NOS cases. The positive rate for GATA3, TBX21 and CD68 was 49.5%,43.1% and 52.3%, respectively. GATA3 high expression was correlated with poor survival through Kaplan-Meier analysis (median OS,120d vs 511d; log-rank P=0.000). CD68 high expression was also correlated with poor survival (median OS,180d vs 450d; log-rank P=0.037).Multivariant analysis further confirmed that GATA3 high expression, along with ECOG score higher than 2, was an independent predictor of OS. An association between GATA3 expression level and B symptom was found (Pearson P=0.006). In vitro studies found that Hut78 expressed the highest level of GATA3 mRNA and protein. Compared with control group, the cell percentage in early apoptosis stage was significantly higher in Hut78-shGATA3. In terms of cytokines, Hut78-shGATA3 transcripted lower levels of IL-4, IL-5, IL-13 and VEGF. This study also induced U937 towards macrophage differentiation through applying lymphoma-conditioned medium. Compared with control group, lower percentages of U937 differentiated towards M2 through shGATA3 medium.CONCLUSION:In PTCL, patients with a positive expression of GATA3 had a shorter OS when compared with a negative GATA3. GATA3, together with ECOG score higher than 2, was an independent predictor of PTCL OS prognosis. The expression level of GATA3 was positively correlated with the expression of CD68, implying a role of GATA3 in promoting macrophage infiltration in the PTCL tissue. Analyzing absolute case numbers, GATA3 high expression was correlated with the presentation of hemophagocytic syndrome. In vitro studies revealed the T cell lymphoma cell line, Hut78, exhibited a significantly higher expression of GATA3. After GATA3 knockdown in T cell lymphoma cell lines, the cell percentage in early apoptosis stage was significantly higher, the expression levels of Th2-associated cytokines and VEGF were lower and the ability to induce M2-type macrophages was weaker. GATA3 may add to the malignant grade of PTCL through these mechanisms.