Division of Pediatric Hematology/Oncology, University of Rochester School of Medicine and Dentistry, Rochester, New York, USA.
Exp Oncol. 2024 Oct 9;46(2):110-118. doi: 10.15407/exp-oncology.2024.02.110.
Acute lymphoblastic leukemia has an intimate physical relationship with nonmalignant bone marrow stromal cells. We have recently demonstrated that stromal cells contribute to the survival of leukemia cells and that there is a bidirectional transfer of intracellular material between them. Understanding the mechanisms of stromal support of leukemia may provide insights into new therapies.
To test the hypothesis that gap junctions are formed between acute lymphoblastic leukemia cells and nonmalignant stromal cells, and that gap junction function is essential for the survival of leukemia cells.
We employed a well-characterized in vitro model of human bone marrow stromal cells and primary human B lymphoblastic leukemia cells and measured leukemia cell survival in coculture using flow cytometry. We measured the effects of gap junction antagonist peptides, carbenoxolone (a drug known to interfere with the gap junction function), and several leukemia chemotherapy drugs including methotrexate upon leukemia cell survival.
We demonstrated that stromal cells need to be alive and metabolically active to keep leukemia cells alive. Physical contact between stromal and leukemia cells leads to an increase in gap junction proteins in leukemia cells. Gap junction inhibitory peptides impaired leukemia cell survival as did carbenoxolone, a nonpeptide inhibitor of the gap junction function. Stromal cell survival was not affected. We observed a very modest enhancement of methotrexate antileukemia activity by low-dose carbenoxolone but no significant interactions with dexamethasone, vincristine, mercaptopurine, or doxorubicin.
These studies demonstrate that acute lymphoblastic cell survival is impaired by interference with the gap junction function. The development of drugs targeting gap junctions may provide a novel approach to the therapy of acute lymphoblastic leukemia.
急性淋巴细胞白血病与非恶性骨髓基质细胞有着密切的物理关系。我们最近证明，基质细胞有助于白血病细胞的存活，并且它们之间存在细胞内物质的双向转移。了解基质对白血病的支持机制可能为新疗法提供启示。
检验以下假设，即急性淋巴细胞白血病细胞与非恶性基质细胞之间形成间隙连接，并且间隙连接功能对于白血病细胞的存活至关重要。
我们采用了一种经过充分验证的人骨髓基质细胞和原发性人 B 淋巴细胞白血病细胞的体外模型，并通过流式细胞术测量共培养物中的白血病细胞存活情况。我们测量了间隙连接拮抗剂肽（已知可干扰间隙连接功能的药物）、卡波醌（carbenoxolone）以及几种白血病化疗药物（包括甲氨蝶呤）对白血病细胞存活的影响。
我们证明，基质细胞需要存活并具有代谢活性才能维持白血病细胞的存活。基质细胞与白血病细胞之间的物理接触会导致白血病细胞中的间隙连接蛋白增加。间隙连接抑制肽会损害白血病细胞的存活，卡波醌作为间隙连接功能的非肽抑制剂也是如此。基质细胞的存活未受影响。我们观察到低剂量卡波醌略微增强了甲氨蝶呤的抗白血病活性，但与地塞米松、长春新碱、巯基嘌呤或阿霉素无明显相互作用。
这些研究表明，干扰间隙连接功能会损害急性淋巴细胞白血病细胞的存活。针对间隙连接的药物开发可能为急性淋巴细胞白血病的治疗提供一种新方法。
