Metalloproteinase inhibition reduces AML growth, prevents stem cell loss, and improves chemotherapy effectiveness.

Acute myeloid leukemia (AML) is a blood cancer of the myeloid lineage. Its prognosis remains poor, highlighting the need for new therapeutic and precision medicine approaches. AML symptoms often include cytopenias linked to loss of healthy hematopoietic stem and progenitor cells (HSPCs). The mechanisms behind HSPC decline are complex and still poorly understood. Here, intravital microscopy (IVM) of a well-established experimental model of AML allows direct observation of the interactions between healthy and malignant cells in the bone marrow (BM), suggesting that physical dislodgment of healthy cells by AML through damaged vasculature may play an important role. Multiple matrix metalloproteinases (MMPs), known to remodel extracellular matrix, are expressed by AML cells and the BM microenvironment. We reason MMPs could be involved in cell displacement and vascular leakiness; therefore, we evaluate the therapeutic potential of MMP pharmacological inhibition using the broad-spectrum inhibitor prinomastat. IVM analyses of prinomastat-treated mice reveal reduced vascular permeability and healthy cell clusters in circulation and lower AML infiltration, proliferation, and cell migration. Furthermore, treated mice have increased retention of healthy HSPCs in the BM and increased survival following chemotherapy. Analysis of a human AML transcriptomic database reveals widespread MMP deregulation, and human AML cells show susceptibility to MMP inhibition. Overall, our results suggest that MMP inhibition could be a promising complementary therapy to reduce AML growth and limit HSPC loss and BM vascular damage caused by MLL-AF9 and possibly other AML subtypes.

Early autologous stem-cell transplantation versus conventional chemotherapy as front-line therapy in high-risk, aggressive non-Hodgkin's lymphoma: an Italian multicenter randomized trial.

PURPOSE: To evaluate the role of early intensification with high-dose therapy (HDT) and autologous stem-cell transplantation (ASCT) as front-line chemotherapy for patients with high-risk, histologically aggressive non-Hodgkin's lymphoma (NHL). PATIENTS AND METHODS: We planned a multicenter, randomized trial to compare a conventional chemotherapy regimen of methotrexate with leucovorin rescue, doxorubicin, cyclophosphamide, vincristine, prednisone, and bleomycin (MACOP-B; arm A) with an abbreviated regimen of MACOP-B (8 weeks) followed by HDT and ASCT (arm B) for intermediate-high-risk/high-risk patients (according to the age-adjusted International Prognostic Index). From September 1994 to April 1998, 150 patients with aggressive lymphoma were enrolled onto the trial. Seventy-five patients were randomly assigned to arm A and 75 patients were randomly assigned to arm B. In both arms, involved-field radiation therapy (36 Gy) was delivered to the site of bulky disease. RESULTS: The rate of complete response was 68% in arm A and 76% in arm B (P = not significant [NS]). Three toxic deaths (4%) occurred in arm B and one (1%) occurred in arm A (P = NS). In arm B, 30 patients (40%) did not undergo HDT and ASCT. According to the intention-to-treat analysis at a median follow-up of 24 months, 5-year overall survival probability in arms A and B was 65% and 64% (P =.95), 5-year progression-free survival was 49% and 61% (P =.21), and 5-year relapse-free survival was 65% and 77% (P =.22), respectively. CONCLUSION: Abbreviated chemotherapy followed by intensification with HDT-ASCT is not superior to conventional chemotherapy in patients with high-risk, aggressive NHL. Additional randomized trials will clarify whether HDT-ASCT as front-line therapy after a complete course of conventional chemotherapy improves survival in this group of patients.