Seeds and soil theory by Stephen Paget at the end of the XIX century.

Transcription

1 Seeds and soil theory by Stephen Paget at the end of the XIX century. In The Distribution Of Secondary Growths In Cancer Of The Breast Paget presents and analyzes 735 fatal cases of breast cancer, complete with autopsy, as well as many other cancer cases from the literature and argues that the distribution of metastases cannot be due to chance, concluding that although the best work in pathology of cancer is done by those who are studying the nature of the seed [the cancer cell], the observations of the properties of the soil" [the secondary organ] "may also be useful... He proposed the seeds (cancer cells) can only establish themselves in those anatomical sites (soil) that provide a congenial ground. Paget S (1889) The distribution of secondary growths in cancer of the breast. Lancet 133:

2 Metastasis is a highly inefficient process in that less than 0.1% of circulating tumor cells are predicted to withstand the harsh stresses of infiltrating and colonizing a distant organ. Numerous studies have identified macrophage as a critical enhancer of metastasis.

3 Human cancers exhibit formidable molecular heterogeneity, to a large extent accounting for the incomplete and transitory efficacy of current anti-cancer therapies. However, neoplastic cells alone do not manifest the disease, but conscript a battery of non-tumor cells to enable and sustain hallmark capabilities of cancer. Escaping immunosurveillance is one of such capabilities. Tumors evolve immunosuppressive microenvironment to subvert anti-tumor immunity

4 Tumors are not just a mixture of neoplastic cells, but they contain multiple stromal cells and extracellular matrix components that together assemble an organ-like structure whereby they interact with the entire organism at a systemic level. Bidirectional cross talk between cancer and stromal cells has been shown to drive tumor growth and metastasis. Molecular profiling of various tumor stromal components has yielded prognostic information, highlighting the tumor microenvironment as a crucial determinant of tumor development. It has become increasingly evident that such interaction resembles the processes often occurring in inflammation, wound healing, and developing organs, with tumors hijacking normal tissue homeostasis to support disease progression

5 Chemokines and their receptors

6 A crucial role is played by the chemokines which regulate the traffic of myeloid, lymphatic and cancer cells

7 In breast cancer, it has been reported that macrophages can constitute as much as 50% of the total cell mass. A meta-analysis performed by Bingle and co- workers showed that an increased macrophage density was associated with poor prognosis in more than 80% of breast cancer cases

8 M1 polarization relies on activation of ERK (MAP Kinases pathways), nuclear factor kappa B (NFκB), and STAT1 signaling, whereas M2 polarization depends on activation of STAT3 and STAT6 pathways. NF-κB and STAT1 signaling suppresses the activation of STAT3 and STAT6 and viceversa. Two different subsets of macrophages also differ in their ability to engage in communication with innate and adaptive immune cells. While M1 macrophages recruit Th1 lymphocytes by producing chemokines including CXCL9 and CXCL10, M2 macrophages attract regulatory T cells, Th2 lymphocytes, basophils, and eosinophils by secreting CCL17, CCL22, and CCL24

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10 CRC: colorectal cancer CTC: circulating tumor cells

11 signaling

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14 periciti fibroblast

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16 Suppression of Antitumor Immunity by Stromal Cells Expressing Fibroblast Activation Protein α Matthew Kraman1,et al. Science 5 November 2010: The stromal microenvironment of tumors, which is a mixture of hematopoietic and mesenchymal cells, suppresses immune control of tumor growth. A stromal cell type that was first identified in human cancers expresses fibroblast activation protein α (FAP). We created a transgenic mouse in which FAP-expressing cells can be ablated. Depletion of FAP-expressing cells, which made up only 2% of all tumor cells in established Lewis lung carcinomas, caused rapid hypoxic necrosis of both cancer and stromal cells in immunogenic tumors by a process involving interferon-γ and tumor necrosis factor α. Depleting FAP-expressing cells in a subcutaneous model of pancreatic ductal adenocarcinoma also permitted immunological control of growth. Therefore, FAP-expressing cells are a nonredundant, immune-suppressive component of the tumor microenvironment.

17 The role of platelets

18 c-met is a powerful oncogene. It is present in cells of epithelial origin whereas HGF is produced by mesenchimal cells. MET is deregulated in many types of human malignancies, including cancers of kidney, liver, stomach, breast, and brain. Various mutations in the MET gene are associated with papillary renal carcinoma

19 MET SIGNALING

20 LEUKOCYTE EXTRAVASATION

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22 Platelets Activated Platelets PF4: platelet factor 4 VWF: von willebrand factor TXA2: tromboxan A2 ANGPT1: angiopoietina 1 PAF: Platelet Activating Factor

23 BMDC: Bone Marrow Derived Dendritic Cells

24 Bone metastasis Bone metastasis are present in 65-80% of metastatic breast and prostate cancers Bone breaks, Pain, increase in blood calcium and nervous compression The invasion by the cancer cells is associated with an activation of the osteoblasts and of the osteoclasts, release of growth factors from the bone matrix that help the cancer cell growth Chemical compounds such as biphosphonates promote the bone reabsorption.

25 Metastasi ossea After leaving the primary cancer and the entrance in the blood District, breast cancer cells Express CXCR4 SDF-1 (CXCL-12) promote: -Chemiotaxis -Survival -Angiogenesis

26 The bone microenvironment is made by an extracellular matrix strongly mineralized and from specific cell types under the control of local and systemic factors that favour cancer cells growth Osteoclasts are myeloid cells that stick to the bone surface by the integrin ALPHAV-BETA3 and secrete collagenases and proteases that destroy the bone matrix M-CSF and RANKL are growth factors produced by the osteoblasts that promote the OSTEOCLASTOGENESIS. RANKL binds RANK on the osteoclasts precursors and induce osteoclastogenesis through NF-KB pathway OPG (OSTEOPROTEGERIN) is a soluble form of RANKL that inhibits the osteoclastogenesis As a consequence the skeleton undergoes a continous dynamic equilibrium so that each year 10% of the skeleton is renewed

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28 Mesenchimal cells (MSC)in the BM are directed along the osteoblast lineage through Local factors such as TGFbeta, BMP e WNT that induce the expression of transcriptional factors such as RUNX2, osterix and ATF (activating transcriptional factors OPG (OSTEOPROTEGERIN) is a soluble form of RANKL that inhibits the osteoclastogenesis

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30 The pre-metastatic niche The concept of the pre-metastatic niche is emerging as a system through which the primary cancer prepares the field for the metastasis to growth. i.e. The presence of inflammatory cells that secrete VEGF, pro-inflammatory chemokines such as CCL2 etc. In the bone the presence of osteopontin (OPN,) an acidic extracellular proteinthat binds calcium and an organic component of bone, secreted by the cancer cells, MMPs, hormons etc. CXCL12 is highly expressed by the osteoblasts and by the stromal cells and recruits metastatic cells that express CXCR4. IL11 e MMP1 are also expressed by the metastatic cells and are a signature that allows the expression of RANKL. AlphaVbeta3 correlates with the metastasis growth since they bind OPN, fibronectin and vitronectin helping the metastatic localization.

31 Osteopontin OPN binds calcium and helps the adesion of osteoclasts to the bone. It binds several integrins and activates the cells of the immune system. It is secreted by osteoblasts, macrophages and many other cell types

32 Signaling Pathways in osteoblasts WNT BMP1 TGF beta

33 WNT BMP1 TGF beta

34 WNT pathway

35 . DKK1 inhibits the WNT pathway and increases osteoclastogenesis. It is high in myeloma

36 Model of Chemokine Regulation of Breast-Cancer Metastasis Murphy, P. M. N Engl J Med 2001;345:

37 TSP-1: Adhesive glycoprotein that mediates cell-to-cell and cell-to-matrix interactions.binds eparin. Ligand for CD36 mediating antiangiogenic properties. Mutations associated with renal cancer.

38 Only 0.01% of circulating cells will give rise to metastasis Tumor cells in bone marrow are: Circulating tumor cells (CTCs) Disseminated tumor cells (DTCs)

39 Features of DTCs and CTCs Cells positive for cytokeratin in bone marrow: The majority of these cells have an epithelial origin, with only 10% of ematopoietic origin. In general, cytokeratines are epithelial markers.

40 The DTCs isolated in patients with early breast cancer with no metastasis, are genetically heterogenous. On the opposite, those isolated from metastatic patients are more homogenous. METASTASI PRECOCE METASTASI AVANZATA

41 -Between dissemination and colonization of a different organ there is a temporary gap during which the cells have to acquire the metastatic competence: this period of time is named latency and the DTC are in G 0 in an equilbrium between proliferation and apoptosis.the DTCs therefore lack the ability to colonize a new organ -Variations in the microenvironment and the expression of metastatic genes allow the passage of the single cells or micro-metastasis to move to the new organ and form macrometastasis

42 CLASSI DI GENI METASTATICI

43 Inhibition of VEGF in lung and brain cancers Cox2 is up-regulated in liver metastasis in the colon cancer Aspirin has a protective function anti-cxcr4 and anti-tgf beta Are in clinical trials in case of bone metastasis

44 n It mediates growth signals n Costitutively active in many tumors n Apoptosis resistence n Mobility Tumorigenic genes Her-2

45 Metastasis initiator PTEN n Mutated in 63% of metastasis of prostate cancer n It is a phosphatasis n It regulates growth, adhesion, migration invasion and apoptosis

46 GENI of metastatic progression PTGS2 n Hyperactive in many cancer metastasis n A PGE-2 enriched metastasis determines: - proliferation - apoptosis inhibition - migration - angiogenesis

47 Gene of the the metastatic virulence VHL n The gene mutated in Hippel Lindau syndrome n The mutation determines an hyperactivation of HIF-1 α n CXCR4 transcription n Cell survival in lung parenchima and bone