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Syndecan-1 and angiogenic cytokines in multiple myeloma: correlation with bone marrow angiogenesis and survival.

Angiogenesis is a complex process involved in the proliferation and metastasis of malignant tumours, and partly triggered by the secretion of various angiogenic factors by tumour cells or cells in the stromal environment. We investigated the correlation between bone marrow angiogenesis, estimated as microvessel density (MVD), and interleukin‐6 (IL‐6), basic fibroblastic growth factor (bFGF), hepatocyte growth factor (HGF) and syndecan‐1 in 67 patients with newly diagnosed multiple myeloma, and evaluated the prognostic value of these parameters. Circulating levels of IL‐6, bFGF, HGF and syndecan‐1 were significantly higher in patients than in controls. Moreover, in patients, bone marrow levels of bFGF, HGF and syndecan‐1 were higher than peripheral blood levels. Positive correlations were found between MVD and syndecan‐1 blood levels (r = 0·33, P = 0·017), syndecan‐1 bone marrow levels (r = 0·49, P = 0·046) and HGF blood levels (r = 0·36, P = 0·008) respectively. High MVD and high blood levels of IL‐6, HGF and syndecan‐1 were predictive of a shorter survival. In a multivariate survival analysis MVD and blood levels of IL‐6 retained independent prognostic significance, while in a survival analysis without MVD the peripheral blood levels of HGF and syndecan‐1 were strong independent prognostic factors.

Hepatocyte growth factor in myeloma patients treated with high-dose chemotherapy.

Summary. Hepatocyte growth factor (HGF) is a cytokine produced by myeloma cells. We examined serum HGF levels in a population of young myeloma patients (median age 52 years) treated with high‐dose chemotherapy. Sera from 128 myeloma patients at diagnosis and serial samples from 16 patients were analysed. Compared with 62 healthy controls, HGF was elevated at diagnosis in 25% of patients (median 0·48 and 1·08 ng/ml respectively; P < 0·0001). The 95 patients who completed therapy were analysed for the impact of HGF on survival. Median survival was not reached after 77 months in the patient group with normal HGF values (< 1·7 ng/ml, n = 69). In the group with elevated HGF (≥ 1·7 ng/ml, n = 26), median survival was 63 months (P = 0·08). In 16 patients, serum was drawn at diagnosis and at the time of expected disease remission (6 weeks to 3 months after chemotherapy). HGF values declined after treatment in 14 of these patients, from a median of 0·9 ng/ml (0·49–1·65) to 0·42 ng/ml (0·32–0·73) (P = 0·005). Our results show that in young myeloma patients HGF is elevated, and that patients with higher levels had a trend towards poorer prognosis. Treatment with high‐dose chemotherapy reduced HGF in the serum of the majority of patients.

The Primary Function of gp130 Signaling in Osteoblasts Is To Maintain Bone Formation and Strength, Rather Than Promote Osteoclast Formation

Interleukin‐6 (IL‐6) family cytokines act via gp130 in the osteoblast lineage to stimulate the formation of osteoclasts (bone resorbing cells) and the activity of osteoblasts (bone forming cells), and to inhibit expression of the osteocyte protein, sclerostin. We report here that a profound reduction in trabecular bone mass occurs both when gp130 is deleted in the entire osteoblast lineage (Osx1Cre gp130 f/f) and when this deletion is restricted to osteocytes (DMP1Cre gp130 f/f). This was caused not by an alteration in osteoclastogenesis, but by a low level of bone formation specific to the trabecular compartment. In contrast, cortical diameter increased to maintain ultimate bone strength, despite a reduction in collagen type 1 production. We conclude that osteocytic gp130 signaling is required for normal trabecular bone mass and proper cortical bone composition.

Osteogenic differentiation of human mesenchymal stem cells in mineralized alginate matrices.

Mineralized biomaterials are promising for use in bone tissue engineering. Culturing osteogenic cells in such materials will potentially generate biological bone grafts that may even further augment bone healing. Here, we studied osteogenic differentiation of human mesenchymal stem cells (MSC) in an alginate hydrogel system where the cells were co-immobilized with alkaline phosphatase (ALP) for gradual mineralization of the microenvironment. MSC were embedded in unmodified alginate beads and alginate beads mineralized with ALP to generate a polymer/hydroxyapatite scaffold mimicking the composition of bone. The initial scaffold mineralization induced further mineralization of the beads with nanosized particles, and scanning electron micrographs demonstrated presence of collagen in the mineralized and unmineralized alginate beads cultured in osteogenic medium. Cells in both types of beads sustained high viability and metabolic activity for the duration of the study (21 days) as evaluated by live/dead staining and alamar blue assay. MSC in beads induced to differentiate in osteogenic direction expressed higher mRNA levels of osteoblast-specific genes (RUNX2, COL1AI, SP7, BGLAP) than MSC in traditional cell cultures. Furthermore, cells differentiated in beads expressed both sclerostin (SOST) and dental matrix protein-1 (DMP1), markers for late osteoblasts/osteocytes. In conclusion, Both ALP-modified and unmodified alginate beads provide an environment that enhance osteogenic differentiation compared with traditional 2D culture. Also, the ALP-modified alginate beads showed profound mineralization and thus have the potential to serve as a bone substitute in tissue engineering.

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.

Bone morphogenetic proteins induce apoptosis in multiple myeloma cells by Smad-dependent repression of MYC

Bone morphogenetic proteins (BMPs) have been shown to induce apoptosis and growth arrest in myeloma cells. However, the molecular mechanisms behind these events are not known. The MYC oncogene is a master regulator of cell growth and protein synthesis and MYC overexpression has been proposed to be associated with the progression of multiple myeloma. Here, we show that BMP-induced apoptosis in myeloma cells is dependent on downregulation of MYC. Moreover, the results suggest that targeting the MYC addiction in multiple myeloma is an efficient way of killing a majority of primary myeloma clones. We also found that myeloma cells harboring immunoglobulin (IG)-MYC translocations evaded BMP-induced apoptosis, suggesting a novel way for myeloma cells to overcome potential tumor suppression by BMPs.

PDL1 Expression on Plasma and Dendritic Cells in Myeloma Bone Marrow Suggests Benefit of Targeted anti PD1-PDL1 Therapy.

In this study we set out to investigate whether anti PDL1 or PD–1 treatment targeting the immune system could be used against multiple myeloma. DCs are important in regulating T cell responses against tumors. We therefore determined PDL1 and PDL2 expression on DC populations in bone marrow of patients with plasma cell disorders using multicolour Flow Cytometry. We specifically looked at CD141+ and CD141- myeloid and CD303+ plasmacytoid DC. The majority of plasma cells (PC) and DC subpopulations expressed PDL1, but the proportion of positive PDL1+ cells varied among patients. A correlation between the proportion of PDL1+ PC and CD141+ mDC was found, suggesting both cell types could down-regulate the anti-tumor T cell response.

Association between high plasma levels of hepatocyte growth factor and progression of radiographic damage in the joints of patients with rheumatoid arthritis

OBJECTIVE Hepatocyte growth factor (HGF) and dickkopf-1 (Dkk-1) inhibit osteoblast differentiation. The present study was thus undertaken to investigate whether plasma levels of HGF and Dkk-1 are related to bone damage in patients with rheumatoid arthritis (RA). METHODS RA patients with a disease duration of <4 years were followed up prospectively with collection of demographic, clinical, and radiographic data at study enrollment (1992) and after 1, 2, 5, and 10 years. Hand radiographs were scored according to the modified Sharp/van der Heijde score (SHS). Levels of HGF and Dkk-1 in stored plasma samples obtained from 136 patients at the time of enrollment were measured by enzyme-linked immunosorbent assay. Associations between cytokine levels and radiographic progression were examined by linear regression analysis. RESULTS Patients with above-median levels of HGF at enrollment had a significantly greater change in the SHS after 1, 2, 5, and 10 years than did patients with below-median levels of HGF (P < 0.001, P = 0.006, P = 0.01, and P = 0.01, respectively). In an unadjusted analysis, baseline HGF levels predicted the severity of joint damage at all time points studied. After adjustment for other known predictors of radiographic progression, baseline HGF levels remained significantly associated with radiographic progression. Plasma levels of Dkk-1 at enrollment were not significantly associated with radiographic progression at any time point studied. CONCLUSION Plasma levels of HGF predict joint damage in RA, and this finding suggests that HGF plays a role in RA joint destruction. The role of HGF as a potential prognostic biomarker or target for treatment warrants further exploration.

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.

High serum YKL-40 concentration is associated with severe bone disease in newly diagnosed multiple myeloma patients.

Objectives:  In multiple myeloma (MM) YKL‐40 is present in the bone marrow microenvironment and is suggested to play a role in remodelling of the extracellular matrix. Here, the association between serum YKL‐40 and severity of bone disease in MM is investigated.