FOXP1 gene in chronic myeloproliferative neoplasms

Abstract

UVOD: Kronične mijeloproliferativne neoplazme (MPN) poremećaji su koštane srži koji se očituju abnormalnom proliferacijom i nakupljanjem zrelih krvnih stanica. FOXP1 gen transkripcijski je faktor važan za normalan razvoj embrionalnog tkiva, te neurološkog i imunološkog sustava. Moguća je povezanost ekspresije FOXP1 gena s nastankom i progresijom kroničnih MPN-ova. ISPITANICI I METODE: Istraživanje je provedeno na 35 pacijenata dijagnosticiranih i liječenih u KB Dubrava, u Zagrebu, u razdoblju između 2006. i 2014. godine, te na 4 zdrava donora koštane srži. Pacijenti su podijeljeni u 5 skupina, prema kliničkim entitetima, te su analizirane njihove demografske i kliničke karakteristike. Iz stanica tkiva koštane srži izolirana je ribonukleinska kiselina (RNA), te podvrgnuta reakciji reverzne transkripcije u svrhu dobivanja komplementarne deoksiribonukleinske kiseline (cDNA), nakon čega je provedeno umnažanje sekvence FOXP1 lančanom reakcijom polimeraze u realnom vremenu (RT-PCR). REZULTATI: Uočavamo kako Philadelphia-negativni (Ph-negativni) klinički i hematološki stabilni MPN-ovi pokazuju nižu relativnu ekspresiju FOXP1 gena u usporedbi s kontrolnom koštanom srži, dok istovremeno pokazuju višu relativnu ekspresiju gena u usporedbi s transformiranim entitetima. Statističkom analizom pokazalo se kako rezultat nije statistički značajan. Smanjena ekspresija gena mogla bi biti povezana s agresivnijom biologijom i sklonošću transformaciji. Analizom preživljenja utvrdili smo kako je smrtnost najviša u transformiranim entitetima, približno jednaka u kroničnim stabilnim oblicima MPN-ova, a najmanja kod reaktivnih eritrocitoza (RE) i reaktivnih trombocitoza (RT). RASPRAVA: Zanimljiva je dvojna funkcija FOXP1 gena, ovisno o vrsti stanica, kao onkogena ili tumor supresorskog gena. Nema mnogo radova o povezanosti FOXP1 gena s MPN-ovima. Usporedno s drugim radovima koji govore u prilog tumor supresorskoj funkciji FOXP1 gena mi nalazimo smanjenu ekspresiju FOXP1 gena kod svih Ph-negativnih MPN-ova, s time da se ekspresija dodatno smanjuje u transformiranim entitetima, što također govori u prilog tumor supresorskoj funkciji gena. ZAKLJUČAK: Ekspresija FOXP1 gena smanjena je kod svih Ph-negativnih MPN-ova u odnosu na kontrolne skupine. Ekspresija FOXP1 gena smanjena je u transformiranim kliničkim entitetima u odnosu na klinički i hematološki stabilne Ph-negativne MPN-ove. Razina ekspresije FOXP1 gena slična je kod policitemije vere (PV), esencijalne trombocitemije (ET) i primarne mijelofibroze (PMF), dok je minimalna ekspresija gena nađena kod leukemijske transformacije u sekundarnu akutnu mijeloičnu leukemiju (sAML).INTRODUCTION: Chronic myeloproliferative neoplasms (MPN) are bone marrow disorders, revealed by abnormal proliferation and accumulation of mature blood cells. FOXP1 gene is a transcription factor important for normal development of embryonal tissue and for neurological and immune systems. There is a possible connection of FOXP1 gene expression with the occurrence as well as progression of chronic MPNs. SUBJECTS AND METHODS: The research included 35 patients diagnosed and treated in Clinical Hospital Dubrava, Zagreb, from 2006 to 2014, as well as 4 healthy bone marrow donors. Patients were divided in 5 groups, according to clinical entities. Their demographic and clinical characteristics were analyzed. From the cells of bone marrow tissue ribonucleid acid (RNA) was isolated and subjected to reverse trascription to obtain complementary deoxyribonucleid acid (cDNA). After that FOXP1 sequence was multiplied with polymerase chain reaction in real time (RT-PCR). RESULTS: We noticed Philadelphia-negative (Ph-negative) clinical and hematological stable MPNs show lower relative FOXP1 gene expression compared to control bone marrow, while also show higher relative gene expression compared to transformed entities. Statistical analysis showed the result was not statistically significant. It is possible lower gene expression is connected to more aggressive biology and greater possibility of transformation. Survival analysis found mortality is the highest in transformed entities, approximately equal in chronic stable MPNs and the lowest in reactive erythrocytosis (RE) and reactive thrombocytosis (RT). DISCUSSION: Dual function of FOXP1 gene as oncogene or tumor suppressor gene depending on the cell type is of interest. There is only a handful of papers on connection between FOXP1 gene and MPNs all indicating tumor suppressing function of FOXP1 gene. We found lower FOXP1 gene expression in all Ph-negative MPNs with the expression further reducing in transformed entities, supporting the tumor suppressing function of the gene. CONCLUSION: FOXP1 gene expression is lower in all Ph-negative MPNs compared to the control group. FOXP1 gene expression is lower in transformed clinical entities compared to clinical and hematological stable Ph-negative MPNs. Level of expression of FOXP1 gene is similar in policitemia vera (PV), essential thrombocythemia (ET) and primary myelofibrosis (PMF). Minimal gene expression was found in leukemic transformation in secondary acute myeloid leukemia (sAML)