Elucidating the expression and function of Numbl during cell adhesion-mediated drug resistance (CAM-DR) in multiple myeloma (MM)

Abstract

BackgroundCell adhesion-mediated drug resistance (CAM-DR) is a major clinical problem that prevents successful treatment of multiple myeloma (MM). In particular, the expression levels of integrin β1 and its sub-cellular distribution (internalization and trafficking) are strongly associated with CAM-DR development.MethodsDevelopment of an adhesion model of established MM cell lines and detection of Numbl and Integrinβ1 expression by Western Blot analysis. The interaction between Numbl and Integrinβ1 was assessed by a co-immunoprecipitation (CO-IP) method. Calcein AM assay was performed to investigate the levels of cell adhesion. Finally, the extent of CAM-DR in myeloma cells was measured using cell viability assay and flow cytometry analysis.ResultsOur preliminary date suggest that Numbl is differentially expressed in a cell adhesion model of MM cell lines. In addition to binding to the phosphotyrosine-binding (PTB) domain, the carboxyl terminal of Numbl can also interact with integrin β1 to regulate the cell cycle by activating the pro-survival PI3K/AKT signaling pathway. This study intends to verify and elucidate the interaction between Numbl and integrin β1 and its functional outcome on CAM-DR. We have designed and developed a CAM-DR model using MM cells coated with either fibronectin or bone marrow stromal cells. We assessed whether Numbl influences cell-cycle progression and whether it, in turn, contributes to activation of PI3K/AKT signal pathway through the adjustment of its carboxyl end. Finally, we showed that the interaction of Numbl with integrin β1 promotes the formation of CAM-DR in MM cells.ConclusionsOur findings elucidated the specific molecular mechanisms of CAM-DR induction and confirmed that Numbl is crucial for the development of CAM-DR in MM cells.

ANXA7 promotes the cell cycle, proliferation and cell adhesion-mediated drug resistance of multiple myeloma cells by up-regulating CDC5L

“…Study has shown that cell adhesion molecules and their mediated adhesion behaviors during the development of tumor drug resistance are all changed [33]. The co-culture of MM plasma cells and BMSCs could activate adhesion molecules to secrete the chemokines and cytokines, which promoting the migration, MM cell growth and drug resistance [34][35][36]. Johannes M et al found that interference of CXCL12 and CXCR4 could functionally interfered with MM chemotaxis to the bone marrow (BM), which led to the resensitization of MM cells to drugs by reversing the CAM-DR in MM [36].…”

CAM-DR: Mechanisms, Roles and Clinical Application in Tumors

“…Studies have shown that in the tumor microenvironment, the adhesion of tumor cells to stromal cells can promote stromal cells to secrete high levels of IL-6, tumor necrosis factor-α, and osteopontin as ligands of integrins to bind and activate integrins ( Damiano et al, 1999 ). Previous studies indicated that integrin β1 was highly expressed on the cell membrane in MM, and the adhesion of MM cells to ECM mediated by integrin β1 could significantly inhibit the apoptosis signal of caspase cells induced by chemotherapeutic drugs ( Rainero and Norman, 2015 ; Huang et al, 2019 ). Hazlehurst et al (2000) also found that integrin β1 mediated cell adhesion to ECM cells significantly increased the protein level of cell cycle inhibitory protein p27 Kip 1 , which blocked cells in the G0/G1 phase, thus escaping the killing effect of toxic drugs.…”

“…In CLL and AML, inhibition of the PI3K/AKT pathway can lead to a decrease in cell proliferation ( Billottet et al, 2006 ; Nguyen et al, 2014 ). Among the studies of CAM-DR in the hematological tumors mentioned above, it has been found that PI3K/AKT is involved in the occurrence and development of CAM-DR in MM and NHL ( Ouyang et al, 2016 ; Huang et al, 2019 ). Moreover, in the solid tumor, adhesion-mediated activation of the PI3K/AKT pathway has also been reported ( Zhu et al, 2012 ; Toth et al, 2019 ).…”

The expression of heat shock protein A12B (HSPA12B) in non-Hodgkin’s lymphomas

“…With this study, we aimed to show that blocking the interaction between tumor cells and stromal cells will be a novel therapeutic target for tumors, especially hematologic malignancies (11). Notably, the proliferation, apoptosis, migration, and invasion of tumor cells are regulated by the expression of oncogenes and tumor suppressor genes, which are usually involved in CAM-DR (12); therefore, CAM-DR could be a key therapeutic target for NHL.…”