Fisiopatologia della malattia mielomatosa dell osso.

Transcription

1 Fisiopatologia della malattia mielomatosa dell osso

2 Cellula staminale Osteoblasto Pre-osteoblasto OSTEOBLASTO Osteocita CONDROCITA Cellula muscolare FIBROBLASTO Osteoblasto a riposo ADIPOCITA Osteoblasto apoptotico

3 Decreasing proliferative capacity/increasing differentiation Time in culture Osteoblast Mesenchymal stem cell Immature progenitor Mature progenitor Preosteoblast Post-proliferative cells Osteoblast Osteocyte Apoptotic cells Inducible/ requires stimulus Default differentiation????? DEX???? DEX PTH LIF EGF IL-1 DEX PTH LIF EGF IL-1 Agent effect on gene expression or depending on the marker analysed DEX PTH???

4 Composition of bone matrix Mineral 65% Organic 35% Collagen type I 30% Non-collagenous proteins osteocalcin, osteonectin 2-3% osteopontin,, BSP, etc 2-3%

5 An osteoclast at work... Carbonic anhydrase II HCO 3 - CO 2 HCO 3 - Cl - Cathepsins MMP s H + Cl - Cathepsins MMP s H + Cl -

6 Osteoclasto (OCL) Proliferazione Differenziazione CFU-GM Fusione Attivazione Apoptosi OCL OCL immaturo immaturo OCL maturo OCL apoptotico

7 Osteoclast M-CSF PTH IL-1 1,25D Proliferation Proliferation, differentiation Fusion TGF-β E 2 P-C-P + Apoptosis Attachment PTH IL-1 - Polarization, resorption

8 BMU and remodeling Cancellous bone represents about 25% of the skeletal mass, with about 28% turnover/year Cortical bone represents about 75% of the skeletal mass, with about 4 % turnover/year The entire adult skeleton is completely remodeled every 10 years!

9 resting osteoblast stromal cell endothelial cell osteocyte lymphocyte/ immunocyte

10 Hormones Stromal-osteoblastic cell Cytokine Growth factors Osteoclast

11 Systemic regulation of bone remodelling PTH 1,25(OH) 2 Vitamin D Calcitonin Estrogen Androgen Growth Hormone/IGF Thyroid hormone Glucocorticoids Bone resorption? Bone formation ( ) ( )? ( )

12 Local regulation of bone remodelling Cytokines that may cause bone loss: IL-1, TNF, IL-6, IL-11 and ODF Cytokines that may prevent bone loss: IL-4, IL-13, IL-18, IFN, OPG and IL-1ra Colony-stimulating factors: M-CSF and GM-CSF Prostaglandins, leukotrienes and nitric oxide Growth factors: IGF, TGF-β, FGF, PDGF and PTHrP

13 OPG e osso osteoblasto/cellula stromale RANK RANKL precursore OC osteoblasto/cellula stromale differenziazione, fusione, attivazione e sopravvivenza degli osteoclasti OPG precursore OC

14 OPG e osso Il bilancio nella produzione di OPG e di RANKL è considerato il principale determinante del numero e dell attivit attività degli osteoclasti e rappresenta la via finale comune alla maggior parte dei fattori locali e sistemici stimolanti il riassorbimento osseo

15 RANKL/RANK/OPG system e.g. PTH Stromal Cell/Osteoblast RANKL OPG Osteoclast precursor RANK c-fms M-CSF srankl Osteoclast Cathepsins MMP s Carbonic anhydrase II HCO - 3 CO 2 HCO - Cl - 3 H + Cl - Cathepsins MMP s H + Cl -

16 OPG e osso RANKL OPG osteoporosi osteopetrosi artrite reumatoide iperparatiroidismo morbo di Paget osteosarcoma mieloma multiplo carcinoma mammario carcinoma prostatico tumore a cellule giganti

17 OPG e sistema immunitario linfocita T RANKL cellula dendritica OPG RANK capacità immunostimolatoria e sopravvivenza delle cellule dendritiche

18 Osteoclastogenesis and bone resorption in RA Hematopoietic progenitor Activated T lymphocyte OPG RANK OCL precursor A: macrophage/type A synovial cell A RANKL M-CSF + RANKL B B: fibroblast/type B synovial cell Osteoblast

19 Multiple myeloma and bone Basic concepts - Bone lytic lesions and osteopenia/osteoporosis, together with bone pain, fractures, hypercalcemia and anemia, are common features of MM - Bone scan by Tc99m bisphosphonate is often negative - Markers of bone resorption are invariably increased; marker of bone formation are decreased in most cases - Therapy of MM dramatically affects bone metabolism

20 Complications of bone cancer Bone pain Increased bone fragility - fractures Bone deformity Hypercalcemia Nerve-compression syndromes Spinal-cord injury

21 Management of MM bone disease Bisphosphonates Analgesics Radiation therapy Reduction of fracture risk through lifestyle changes

22 Lymphocyte Endothelial cells Osteoblast Myeloma cells Stromal cells Osteoclast

23 Blood 101: , 2003 RANKL and osteoprotegerin in myeloma bone disease. Sezer O, Heider U, Zavrski I, Kuhne CA, Hofbauer LC

24 Osteoclast Activating Factors (OAFs) - Che cosa sono? - presenti nel microambiente midollare in MM, ma non in MGUS / sano - capaci di stimolare il riassorbimento osseo - il blocco della loro attività previene il riassorbimento - Chi li produce? - Pleiotropismo

25 Stromal cells RANKL - OPG PTHrP HGF IL-1, TNF IL-6 Osteoclast Myeloma cells VEGF MIP-1α

26 Myeloma cells

27 Osteoblasts RANKL - OPG IL-1, TNF PDGF-BB NCAM IGFBP-4 IL-6 Myeloma cells VEGF Osteoclast MIP-1α

28 sil-6r 6Rα IL-6 Myeloma cells gp130 IL sil-6rαsil-6r mil-6r 6Rα Stromal cells α 4 β 1 - VCAM-1 KSHV

29 Approaches to treating bone metastases Therapy Mechanism Stage of development BISPHOSPHONATES Block bone resorption. Block vicious circle osteoclasts/cancer cells. Alleviate bone pain. Reduce bone homing and growth of cancer cells On the market OSTEOPROTEGERIN Prevents RANKL from binding its receptor and osteoclastogenesis Phase II RANK-Fc Prevents RANKL from binding its receptor and osteoclastogenesis Phase I PTHrP antibodies Neutralize PTHrP Phase III vitamin-d analogues Decrease PTHrP Phase III

30 Osteoclast CO 2 Carbonic anhydrase II HCO 3 - HCO 3 - HCO 3 - Cl - Vitronectin receptor Cathepsins MMP s Vacuolar ATPase H + Cl - CIC-7 chloride channel Cathepsins H + Cl - MMP s

31 PNAS 98: , 2001 Multiple myeloma disrupts the TRANCE/ osteoprotegerin cytokine axis to trigger bone destruction and promote tumor progression. Pearse RN, Sordillo EM, Yaccoby S, Wong BR, Liau DF, Colman N, Michaeli J, Epstein J, Choi Y Br J Haematol 116: , 2002 Myeloma interacts with the bone marrow microenvironment to induce osteoclastogenesis and is dependent on osteoclast acitvity. Yaccoby S, Pearse RN, Johnson CL, Barlogie B, Choi Y, Epstein J

32 OAFs Tumor cells Osteoclast Growth factors

33 Osteoblasts Stromal cells RANKL - OPG IL-6 VEGF OAFs Osteoclast Myeloma cells IL-6 TGF-β, IGFs

34 Chemical structure O - O - O - R O - O P O P O O P C P O O - O - O - R O - Pyrophosphate Geminal bisphosphonate

35 Mode of action of bisphosphonates Binding to apatite crystals Preferential accumulation under osteoclasts Local release during bone resorption osteoclast activity - decreased ruffled border - altered cytoskeleton - decreased acid production - decreased enzyme activity - decreased prenylation - incorporation into nucleotides osteoclast number - increased apoptosis - decreased recruitment - osteoblast lineage cells

36 3-Hydroxy-3-Methylglutaril-CoA Mevalonate Inhibit HMG-CoA reductase Statins Dimethylallyl-PP Isopentenyl-PP Geranyl-PP Inhibit Farnesyl-PP synthase Nitrogen-containing bisphosphonates Small GTPases (Ras, Rho, Rab, Rac) Squalene Cholesterol Farnesyl-PP Geranylgeranyl-PP Protein prenylation

37 BPs sites of action Lymphocyte Endothelial cells Osteoblast Myeloma cells Stromal cells Osteoclast

38 Bisphosphonates and malignant bone disease Basic concepts The efficacy of BPs has been clearly demonstrated in patients with breast cancer and multiple myeloma - BPs prolong the complication-free survival time and preserve quality of life The safety of long-term bisphosphonate administration has been well documented

39 The Cochrane Library, Issue 4, 2002 Bisphosphonates in multiple myeloma. Djulbegovic B, Whatley K, Ross J, Clark O, Bos G, Goldschmidt H, Cremer F, Alsina M, Glasmacher A J Clin Oncol 20: , 2002 American Society of Clinical Oncology Clinical Practice Guidelines: The role of bisphosphonates in multiple myeloma Berenson JR, Hillner BE, Kyle RA, Anderson K, Lipton A, Yee GC, Biermann for the American Society of Clinical Oncology Bisphosphoantes Expert Panel

40 The Cochrane Library, Issue 4, 2002 Bisphosphonates in multiple myeloma. Djulbegovic B, Whatley K, Ross J, Clark O, Bos G, Goldschmidt H, Cremer F, Alsina M, Glasmacher A Adding bisphoshponates to the treatment of multiple myeloma reduces vertebral fractures, probably pain and possibly the incidence of hypercalcemia. Their effects on mortality and definitive results about the effect on pain and the incidence of hypercalcemia await further analysis. On current evidence clodronate or pamidronate may be the preferred agents.

41 J Clin Oncol 20: , 2002 American Society of Clinical Oncology Clinical Practice Guidelines: The role of bisphosphonates in multiple myeloma Berenson JR, Hillner BE, Kyle RA, Anderson K, Lipton A, Yee GC, Biermann for the American Society of Clinical Oncology Bisphosphoantes Expert Panel Because there are no direct comparisons between clodronate and pamidronate or zoledronic acid, the superiority of one agent cannot be definitively established. However, the panel recommends only intravenous pamidronate or zoledronic acid in light of the use of the time to first skeletal event as the primary end point and more complete assessment of bony complications in studies evaluating it. Additionally, clodronate is not available in the United States

42 Conclusioni La malattia mielomatosa dell osso è la conseguenza delle alterazioni del rimodellamento osseo indotte localmente dalle plasmacellule tumorali, che stimolano l attività osteoclastica attraverso numerosi OAFs e l aumento del rapporto RANKL/OPG Lo studio del rimodellamento normale e patologico permette l identificazione di nuovi bersagli terapeutici La crescita del mieloma è strettamente dipendente dalle caratteristiche del microambiente, incluso il riassorbimento osseo L attività anti-tumorale dei farmaci inibenti il riassorbimento osseo è supportata da numerosi dati pre-clinici, ma attende una dimostrazione nell uomo