Torstein Baade Rø

Bone morphogenetic protein-5, -6 and -7 inhibit growth and induce apoptosis in human myeloma cells

Previously, bone morphogenetic protein (BMP)-2 and -4 have been shown to inhibit proliferation and induce apoptosis in human myeloma cells. BMP-2 and -4 belong to a subgroup of BMPs using the BMP receptors Alk-3 or -6. In this study, we examined the effects on human myeloma cells of BMP-6 and -7, members of a different BMP subgroup, which mainly utilize Alk-2 as their receptor. All cell lines examined expressed mRNA for the BMP-6 and -7 receptor Alk-2. We did not detect transcripts for the BMP-2 and -4 receptors Alk-3 or Alk-6 in INA-6 and RPMI-8226 cells by RT–PCR. Accordingly, the intracellular signalling molecules Smad-1, -5 and -8 were not phosphorylated by BMP-4 in INA-6 and RPMI-8226 cells. The expression patterns of various BMP receptors in the myeloma cell lines explained the differences in responses to the various BMPs. Alk-2-expressing cell lines responded with growth inhibition and apoptosis to BMP-6 and -7, whereas cell lines lacking both Alk-3 and -6 were resistant to BMP-4. Soluble Alk-3 and -6 were able to neutralize the BMP-4 effects in BMP-4-responsive cell lines. All BMPs reduced viability in more than 70% of purified primary myeloma cell samples. BMPs have intriguing antitumor effects in vitro. Importantly, myeloma cells not responsive to BMP-2 and -4 may still be sensitive to BMP-6 or -7. It is possible that therapeutic use of BMP or BMP analogues could have an impact on both myeloma bone disease and myeloma cell growth.

A selective c-Met inhibitor blocks an autocrine hepatocyte growth factor growth loop in ANBL-6 cells and prevents migration and adhesion of myeloma cells

Purpose: We wanted to examine the role of the hepatocyte growth factor (HGF) receptor c-Met in multiple myeloma by applying a novel selective small molecule tyrosine kinase inhibitor, PHA-665752, directed against the receptor. Experimental Design: Four biological sequels of HGF related to multiple myeloma were studied: (1) proliferation of myeloma cells, (2) secretion of interleukin-11 from osteogenic cells, (3) migration of myeloma cells, and (4) adhesion of myeloma cells to fibronectin. We also examined effects of the c-Met inhibitor on intracellular signaling pathways in myeloma cells. Results: PHA-665752 effectively blocked the biological responses to HGF in all assays, with 50% inhibition at 5 to 15 nmol/L concentration and complete inhibition at around 100 nmol/L. PHA-665752 inhibited phosphorylation of several tyrosine residues in c-Met (Tyr1003, Tyr1230/1234/1235, and Tyr1349), blocked HGF-mediated activation of Akt and p44/42 mitogen-activated protein kinase, and prevented the adaptor molecule Gab1 from complexing with c-Met. In the HGF-producing myeloma cell line ANBL-6, PHA-665752 revealed an autocrine HGF–c-Met–mediated growth loop. The inhibitor also blocked proliferation of purified primary myeloma cells, suggesting that autocrine HGF–c-Met–driven growth loops are important for progression of multiple myeloma. Conclusions: Collectively, these findings support the role of c-Met and HGF in the proliferation, migration, and adhesion of myeloma cells and identify c-Met kinase as a therapeutic target for treatment of patients with multiple myeloma.

Hepatocyte growth factor promotes migration of human myeloma cells

This study demonstrates that myeloma cells can be attracted to hepatocyte growth factor in concentrations known to be present in the bone marrow of patients with multiple myeloma. Multiple myeloma is characterized by the accumulation and dissemination of malignant plasma cells in the bone marrow. Cell migration is thought to be important for these events. We studied migration in a Transwell two-chamber assay and tested the motogenic effect of various cytokines. In addition to insulin-like growth factor-1 and stromal cell-derived growth factor-1α, previously known as chemoattractants for myeloma cells, we identified hepatocyte growth factor as a potent attractant for myeloma cells. Hepatocyte growth factor-mediated migration was dependent on phosphatidylinositol-3-kinase, involved the MAPK/Erk signaling cascade and VLA-4 integrins, but did not involve Akt, mTOR or G proteins.

Targeting Proliferating Cell Nuclear Antigen and Its Protein Interactions Induces Apoptosis in Multiple Myeloma Cells

Multiple myeloma is a hematological cancer that is considered incurable despite advances in treatment strategy during the last decade. Therapies targeting single pathways are unlikely to succeed due to the heterogeneous nature of the malignancy. Proliferating cell nuclear antigen (PCNA) is a multifunctional protein essential for DNA replication and repair that is often overexpressed in cancer cells. Many proteins involved in the cellular stress response interact with PCNA through the five amino acid sequence AlkB homologue 2 PCNA-interacting motif (APIM). Thus inhibiting PCNA’s protein interactions may be a good strategy to target multiple pathways simultaneously. We initially found that overexpression of peptides containing the APIM sequence increases the sensitivity of cancer cells to contemporary therapeutics. Here we have designed a cell-penetrating APIM-containing peptide, ATX-101, that targets PCNA and show that it has anti-myeloma activity. We found that ATX-101 induced apoptosis in multiple myeloma cell lines and primary cancer cells, while bone marrow stromal cells and primary healthy lymphocytes were much less sensitive. ATX-101-induced apoptosis was caspase-dependent and cell cycle phase-independent. ATX-101 also increased multiple myeloma cells’ sensitivity against melphalan, a DNA damaging agent commonly used for treatment of multiple myeloma. In a xenograft mouse model, ATX-101 was well tolerated and increased the anti-tumor activity of melphalan. Therefore, targeting PCNA by ATX-101 may be a novel strategy in multiple myeloma treatment.

Growth, body composition and metabolic profile of 8-year-old children exposed to metformin in utero

Objectives. To investigate the possible long-term effects of metformin exposure on growth and development of the offspring born to mothers with polycystic ovary syndrome (PCOS). The drug passes through the placenta and can potentially influence the fetus. Patients and methods. This is a follow-up study of a randomized, controlled trial on PCOS women, randomized to metformin or placebo in pregnancy. Out of 37 children aged 7–9 years, 25 agreed to participate. Primary outcome measures were growth, body composition and metabolic parameters. Results. There were no differences in height, weight or body composition between those exposed to metformin and those exposed to placebo. We found a higher fasting glucose level in the metformin group (4.93 mmol/L vs. 4.60 mmol/L, p = 0.04). In the metformin group there was a trend towards higher systolic blood pressure (106 mmHg vs. 101 mmHg, p = 0.05) and a lower LDL cholesterol level (2.42 mmol/L vs. 2.99 mmol/L, p = 0.07). Conclusion. Metformin exposure during fetal life does not seem to influence growth and body composition at the age of 8 years. A higher fasting glucose level and a possible higher systolic blood pressure and lower LDL cholesterol level in the metformin group may be coincidental and should be further explored.

High expression of BCL3 in human myeloma cells is associated with increased proliferation and inferior prognosis

Background:  BCL3 is a putative oncogene encoding for a protein belonging to the inhibitory κB‐family. We experienced that this putative oncogene was a common target gene for growth‐promoting cytokines in myeloma cell lines.

Anti-c-MET Nanobody - a new potential drug in multiple myeloma treatment.

c‐MET is the tyrosine kinase receptor of the hepatocyte growth factor (HGF). HGF‐c‐MET signaling is involved in many human malignancies, including multiple myeloma (MM). Recently, multiple agents have been developed directed to interfere at different levels in HGF‐c‐MET signaling pathway. Nanobodies® are therapeutic proteins based on the smallest functional fragments of heavy‐chain‐only antibodies. In this study, we wanted to determine the anticancer effect of a novel anti‐c‐MET Nanobody in MM.

Lymphoma and myeloma cells are highly sensitive to growth arrest and apoptosis induced by artesunate

The use of new drugs has improved the treatment of multiple myeloma and diffuse large B‐cell lymphoma (DLBCL). Nevertheless, over time many patients relapse and develop resistance to treatment, and efforts are needed to overcome drug resistance. The widely used malaria drug artesunate has been reported to have antitumor activity, and we aimed to test the effects of artesunate on a panel of myeloma and lymphoma cells.

Decorin is down-regulated in multiple myeloma and MGUS bone marrow plasma and inhibits HGF-induced myeloma plasma cell viability and migration†

Decorin is a stromal‐produced small leucine‐rich proteoglycan known to attenuate tumour pro‐survival, migration, proliferation and angiogenic signalling pathways. Recent studies have shown that decorin interacts with the hepatocyte growth factor (HGF) receptor c‐Met, a potential key pathway in multiple myeloma (MM).

Bone morphogenetic protein-9 suppresses growth of myeloma cells by signaling through ALK2 but is inhibited by endoglin.

Multiple myeloma is a malignancy of plasma cells predominantly located in the bone marrow. A number of bone morphogenetic proteins (BMPs) induce apoptosis in myeloma cells in vitro, and with this study we add BMP-9 to the list. BMP-9 has been found in human serum at concentrations that inhibit cancer cell growth in vitro. We here show that the level of BMP-9 in serum was elevated in myeloma patients (median 176 pg/ml, range 8–809) compared with healthy controls (median 110 pg/ml, range 8–359). BMP-9 was also present in the bone marrow and was able to induce apoptosis in 4 out of 11 primary myeloma cell samples by signaling through ALK2. BMP-9-induced apoptosis in myeloma cells was associated with c-MYC downregulation. The effects of BMP-9 were counteracted by membrane-bound (CD105) or soluble endoglin present in the bone marrow microenvironment, suggesting a mechanism for how myeloma cells can evade the tumor suppressing activity of BMP-9 in multiple myeloma.