Hematopoietic Stem Cell Mobilization and Homing after Transplantation: The Role of MMP-2, MMP-9, and MT1-MMP

Hematopoietic stem/progenitor cells (HSPCs) are used in clinical transplantation to restore hematopoietic function. Here we review the role of the soluble matrix metalloproteinases MMP-2 and MMP-9, and membrane type (MT)1-MMP in modulating processes critical to successful transplantation of HSPC, such as mobilization and homing. Growth factors and cytokines which are employed as mobilizing agents upregulate MMP-2 and MMP-9. Recently we demonstrated that MT1-MMP enhances HSPC migration across reconstituted basement membrane, activates proMMP-2, and contributes to a highly proteolytic bone marrow microenvironment that facilitates egress of HSPC. On the other hand, we reported that molecules secreted during HSPC mobilization and collection, such as hyaluronic acid and thrombin, increase MT1-MMP expression in cord blood HSPC and enhance (prime) their homing-related responses. We suggest that modulation of MMP-2, MMP-9, and MT1-MMP expression has potential for development of new therapies for more efficient mobilization, homing, and engraftment of HSPC, which could lead to improved transplantation outcomes

Effect on Patients’ Outcomes of a Change to Biosimilar Filgrastim Product in Autologous Stem Cell Mobilization

Background: Following addition of a biosimilar filgrastim product to the formulary, sites in the authors’ provincial health authority transitioned from using the originator filgrastim to the biosimilar for autologous stem cell mobilization. Objective: To assess the effect on patient outcomes of a universal change to use of the biosimilar filgrastim in stem cell mobilization. Methods: This retrospective pre–post study included patients undergoing autologous stem cell mobilization at 2 cancer hospitals in Alberta, Canada, between July 1, 2018, and November 30, 2019. Clinical outcomes were investigated for patients treated with a granulocyte colony-stimulating factor (biosimilar or originator product) for mobilization before stem cell transplant, approximately 6 months before and after the defined date of product change. Results: In total, 102 patients were treated with the originator product and 101 patients with the biosimilar. Effectiveness was similar between the originator and biosimilar products, with 98% successful harvest of stem cells in all patients treated. Independent t tests showed no statistically significant differences between patients receiving the originator and those receiving the biosimilar in terms of time from mobilization to collection (difference of means –0.9 days, 95% confidence interval [CI] –2.12 to 0.32), time for neutrophil engraftment (difference of means 0 days, 95% CI –0.36 to 0.36), time for platelet engraftment (difference of means 1 day, 95% CI –0.55 to 2.55), average length of stay (difference of means –0.7 day, 95% CI –2.71 to 1.31), and CD34+ value (difference of means –1 × 106/kg body weight, 95% CI –2.11 to 0.11). A 98% rate of conversion to use of the biosimilar filgrastim was achieved, with an estimated annual drug-cost saving of $67 500. Conclusions: In this pre–post study, changing to the biosimilar product from the originator maintained clinical effectiveness outcomes while decreasing overall drug expenditures. A well-planned change to the biosimilar product, executed in conjunction with clinician consultation and monitoring of effectiveness outcomes, can ensure appropriate patient therapy while significantly improving the uptake of biosimilars and decreasing expenditures for biologic drugs. RÉSUMÉ Contexte : À la suite de l’ajout d’un produit filgrastim biosimilaire à la liste des médicaments, les sites relevant de l’autorité sanitaire provinciale des auteurs sont passés de l’utilisation du filgrastim princeps à la version générique pour la mobilisation des cellules souches autologues. Objectif : Évaluer l’effet sur les résultats des patients d’un changement généralisé visant à utiliser le filgrastim générique pour la mobilisation des cellules souches. Méthodes : Cette étude rétrospective pré-post comprenait des patients soumis à une mobilisation des cellules souches autologues dans deux hôpitaux de cancérologie en Alberta (Canada) entre le 1er juillet 2018 et le 30 novembre 2019. L’examen des résultats cliniques des patients traités à l’aide d’un facteur stimulant les colonies de granulocytes (G-CSF) (générique ou princeps) pour une mobilisation avant la greffe de cellules souches a eu lieu environ six mois avant et après la date du changement de produit. Résultats : Au total, 102 patients ont été traités à l’aide du produit princeps et 101 patients à l’aide du générique. Les deux produits présentaient une efficacité similaire, et 98$. Conclusions : Dans cette étude pré-post, le passage du produit princeps au générique a préservé l’efficacité des résultats cliniques, tout en diminuant les dépenses générales liées au médicament. Un changement bien programmé pour passer au produit générique, mené conjointement avec la consultation d’un clinicien et un contrôle des résultats d’efficacité, peut assurer une thérapie du patient appropriée tout en améliorant grandement la prise de produits génériques et en diminuant les dépenses associées aux médicaments biologiques.

Hyaluronic Acid and Thrombin Upregulate MT1-MMP Through PI3K and Rac-1 Signaling and Prime the Homing-Related Responses of Cord Blood Hematopoietic Stem/Progenitor Cells

One of the hurdles of cord blood (CB) transplantation is delayed hematopoietic engraftment. Previously, we demonstrated that supernatants isolated from leukapheresis products of granulocyte-colony stimulating factor (G-CSF)-mobilized patients primed the homing of hematopoietic stem/progenitor cells (HSPC) by enhancing their chemotactic responses to stromal cell-derived factor (SDF)-1 and stimulating matrix metalloproteinases (MMPs) MMP-2 and MMP-9. Since membrane type 1 (MT1)-MMP activates proMMP-2 and localizes proteolytic activity at the leading edge of migrating cells, in this study we investigated whether MT1-MMP contributes to the priming of the homing-related responses of CB HSPC. We found that components of supernatants of leukapheresis products such as hyaluronic acid and thrombin (i) increase the secretion of proMMP-9 and transcription and protein synthesis of MT1-MMP in CB CD34+ cells; (ii) increase the levels of active MMP-2 in co-cultures of CD34+ cells with endothelial cells; (iii) increase the chemoinvasion across reconstituted basement membrane Matrigel of CD34+ cells toward a low SDF-1 gradient (20 ng/mL); and (iv) activate mitogen-activated protein kinase, phosphatidylinositol 3-kinase, and Rac-1 signaling pathways. Inhibition of phosphatidylinositol 3-kinase and Rac-1 by their respective inhibitors LY290042 and NSC23766 attenuated MT1-MMP expression in CB CD34+ cells, leading to reduced proMMP-2 activation and HSPC trans-Matrigel chemoinvasion toward SDF-1. Thus, our data suggest that MT1-MMP plays an important role in the homing-related responses of HSPC, and we propose that pretreatment of CB HSPC with hyaluronic acid or thrombin before transplantation could improve their homing and engraftment

Membrane Type-1 Matrix Metalloproteinase Expression in Acute Myeloid Leukemia and Its Upregulation by Tumor Necrosis Factor-α

Membrane type-1 matrix metalloproteinase (MT1-MMP) has been implicated in tumor invasion, as well as trafficking of normal hematopoietic cells, and acts as a physiologic activator of proMMP-2. In this study we examined MT1-MMP expression in primary acute myeloid leukemia (AML) cells. Because tumor necrosis factor (TNF)-α is known to be elevated in AML, we also investigated the effect of TNF-α on MT1-MMP expression. We found (i) MT1-MMP mRNA expression in 41 out of 43 primary AML samples tested; (ii) activation of proMMP-2 in co-cultures of AML cells with normal bone marrow stromal cells; and (iii) inhibition of proMMP-2 activation and trans-Matrigel migration of AML cells by gene silencing using MT1-MMP siRNA. Moreover, recombinant human TNF-α upregulated MT1-MMP expression in AML cells resulting in enhanced proMMP-2 activation and trans-Matrigel migration. Thus, AML cells express MT1-MMP and TNF-α enhances it leading to increased MMP-2 activation and most likely contributing to the invasive phenotype. We suggest that MT1-MMP, together with TNF-α, should be investigated as potential therapeutic targets in AML