Overcoming Microenvironment-Mediated Chemoprotection through Stromal Galectin-3 Inhibition in Acute Lymphoblastic Leukemia

Abstract

Environmentally-mediated drug resistance in B-cell precursor acute lymphoblastic leukemia (BCP-ALL) significantly contributes to relapse. Stromal cells in the bone marrow environment protect leukemia cells by secretion of chemokines as cues for BCP-ALL migration towards, and adhesion to, stroma. Stromal cells and BCP-ALL cells communicate through stromal galectin-3. Here, we investigated the significance of stromal galectin-3 to BCP-ALL cells. We used CRISPR/Cas9 genome editing to ablate galectin-3 in stromal cells and found that galectin-3 is dispensable for steady-state BCP-ALL proliferation and viability. However, efficient leukemia migration and adhesion to stromal cells are significantly dependent on stromal galectin-3. Importantly, the loss of stromal galectin-3 production sensitized BCP-ALL cells to conventional chemotherapy. We therefore tested novel carbohydrate-based small molecule compounds (Cpd14 and Cpd17) with high specificity for galectin-3. Consistent with results obtained using galectin-3-knockout stromal cells, treatment of stromal-BCP-ALL co-cultures inhibited BCP-ALL migration and adhesion. Moreover, these compounds induced anti-leukemic responses in BCP-ALL cells, including a dose-dependent reduction of viability and proliferation, the induction of apoptosis and, importantly, the inhibition of drug resistance. Collectively, these findings indicate galectin-3 regulates BCP-ALL cell responses to chemotherapy through the interactions between leukemia cells and the stroma, and show that a combination of galectin-3 inhibition with conventional drugs can sensitize the leukemia cells to chemotherapy.

Shotgun Proteomics of Co-Cultured Leukemic and Bone Marrow Stromal Cells from Different Species as a Preliminary Approach to Detect Intercellular Protein Transfer

“…The reduced sensitivity to chemotherapeutic drugs and oxidative stress of leukemic cells co-cultured with stromal cells has been reported previously [ 11 , 12 , 13 , 14 , 15 , 33 , 34 , 35 ]. Co-cultures of mouse and human cells have been used to study this effect [ 11 , 14 , 34 , 35 ], and the intercellular transfer of mitochondria, vesicles, and galectin-3 from MSC to leukemic cells, has been associated with this protection in experimental settings where transfer goes from human to human [ 9 , 15 , 16 , 36 ] and from mouse to human cells [ 11 , 14 , 15 , 16 ].…”

“…The reduced sensitivity to chemotherapeutic drugs and oxidative stress of leukemic cells co-cultured with stromal cells has been reported previously [ 11 , 12 , 13 , 14 , 15 , 33 , 34 , 35 ]. Co-cultures of mouse and human cells have been used to study this effect [ 11 , 14 , 34 , 35 ], and the intercellular transfer of mitochondria, vesicles, and galectin-3 from MSC to leukemic cells, has been associated with this protection in experimental settings where transfer goes from human to human [ 9 , 15 , 16 , 36 ] and from mouse to human cells [ 11 , 14 , 15 , 16 ]. In these reports, cells interacted in 2D co-cultures, in which leukemic cells grew on top of a monolayer of stromal cells; only the work of Kolba and coworkers, using the Trans-SILAC method and chronic myeloid leukemia cells, provided a proteome-scale map of the transferred proteins [ 9 ].…”

“…One of the limitations of the present study is the need of cells from different species which entails the possibility that the observed results do not replicate in the model of two cell types of one origin. In this regard, the co-culture of mouse MSC and human leukemic cells has been used to study the protection against chemotherapeutic drugs and intercellular mitochondrial transfer [ 11 , 12 , 14 , 15 , 16 , 34 , 35 ]. These effects have been replicated in co-cultured human cells [ 9 , 10 , 33 , 36 ].…”

“…Some mechanisms of intercellular communication involve the transfer of proteins, vesicles, and organelles, which contributes to drug and stress resistance of leukemic cells [ 8 , 9 , 10 , 11 ]. For example, the multifunctional protein galectin-3 of stromal origin induces the production of endogenous galectin-3 in ALL cells, and the intracellular content of this protein positively correlates with tolerance to vincristine and nilotinib [ 12 , 13 , 14 ]. Moreover, the transfer of membrane-enclosed vesicles from MSC to chronic myeloid leukemia cells protects the latter against imatinib [ 9 ], and the mitochondrial transfer from MSC to ALL or AML cells, protects against cytarabine [ 11 , 15 ].…”

Characterization of mesenchymal stem cells in pre-B acute lymphoblastic leukemia

“…While less is known about the BMM of B-ALL, studies have shown that MSCs promote engraftment, survival and chemoresistance of B-ALL cells (Iwamoto et al, 2007;Nwabo Kamdje et al, 2011;Frolova et al, 2012;Jacamo et al, 2014;Hu et al, 2015;Mallampati et al, 2015;Polak et al, 2015;Burt et al, 2019;Portale et al, 2019;Yu et al, 2019;Ruiz-Aparicio et al, 2020;Tarighat et al, 2021). Furthermore, B-ALL cells are capable of disrupting the proliferation, differentiation, protein expression, signaling pathway activation and hematopoietic-supporting capabilities of MSCs (Conforti et al, 2013;Jacamo et al, 2014;van den Berk et al, 2014;Vicente Lopez et al, 2014;Polak et al, 2015;Balandran et al, 2016;de Rooij et al, 2017;Vernot et al, 2017;Ma et al, 2019;Portale et al, 2019;Yu et al, 2019;Verma et al, 2020;Vanegas et al, 2021).…”