Chattopadhyay Sukalpa, Chaklader Malay, Law Sujata
Stem Cell Research and Application Unit, Department of Biochemistry and Medical Biotechnology, Calcutta School of Tropical Medicine, 108, C.R. Avenue, Kolkata, West Bengal, 700 073, India.
Tissue Engineering Laboratory, Skeletal Biology and Engineering Research Center, Prometheus, Division of Skeletal Tissue Engineering, KU Leuven, O&N1, Herestraat 49, Box 81313, 3000, Leuven, Belgium.
J Cell Commun Signal. 2019 Mar;13(1):39-52. doi: 10.1007/s12079-018-0470-6. Epub 2018 Jul 5.
The evolutionarily conserved Wnt signaling pathway regulates physiological hematopoiesis, a process of formation of blood cells and has been shown to play crucial role in the development of both myeloid and lymphoid malignancies. The Wnt signaling pathway can be broadly divided into canonical and non-canonical pathways. In the present study, we investigated the pathobiology of leukemia by studying the expression profile of Wnt proteins, receptors, key signaling intermediates and endogenous Wnt antagonist involved in canonical and non-canonical pathways in the bone marrow (BM) hematopoietic stem/progenitor cell (HSPC) compartment of experimental leukemic mice. Cell adhesion molecule N-Cadherin and leukemic BM microenvironment with reference to Wnt were also studied. We used ENU, a potent carcinogen, to induce leukemia in wild type Swiss albino mice and malignant transformation was cofirmed by peripheral blood and BM studies. Flow cytometric expression analysis revealed profound up-regulation of canonical Wnt3a/β-catenin/CyclinD1 signaling axis along with N-Cadherin whereas down-regulation of non-canonical Wnt5a/Ca/CaMKII signaling axis in the leukemic HSPC compartment. Subsequent use of anti-Wnt3a antibody in the in vitro clonogenicity assay uncovered that anti-Wnt3a antibody preferentially inhibited the growth and number of the primitive leukemic hematopoietic CFU-GEMM and BFU-E colonies. Stromal cells derived from the leukemic BM also exhibited aberrant Wnt3a and Wnt5a protein expression. Taken together, alteration of canonical and non-canonical Wnt signaling pathways in the HSPC compartment along with classical Wnt protein expression pattern in the leukemic stromal microenvironment resulted in progression of leukemia.
进化上保守的Wnt信号通路调节生理性造血作用，即血细胞形成过程，并且已显示在髓系和淋巴系恶性肿瘤的发展中起关键作用。Wnt信号通路可大致分为经典途径和非经典途径。在本研究中，我们通过研究参与实验性白血病小鼠骨髓（BM）造血干/祖细胞（HSPC）区室中经典和非经典途径的Wnt蛋白、受体、关键信号中间体和内源性Wnt拮抗剂的表达谱，来研究白血病的病理生物学。还研究了细胞粘附分子N-钙粘蛋白以及与Wnt相关的白血病BM微环境。我们使用强效致癌物ENU在野生型瑞士白化小鼠中诱导白血病，并通过外周血和BM研究证实了恶性转化。流式细胞术表达分析显示，白血病HSPC区室中经典的Wnt3a/β-连环蛋白/细胞周期蛋白D1信号轴以及N-钙粘蛋白显著上调，而非经典的Wnt5a/Ca/CaMKII信号轴下调。随后在体外克隆形成试验中使用抗Wnt3a抗体发现，抗Wnt3a抗体优先抑制原始白血病造血CFU-GEMM和BFU-E集落的生长和数量。来自白血病BM的基质细胞也表现出异常的Wnt3a和Wnt5a蛋白表达。综上所述，HSPC区室中经典和非经典Wnt信号通路的改变以及白血病基质微环境中经典Wnt蛋白表达模式导致了白血病的进展。
