Tensins 123

tensins in health and disease,

1. TENSINS IN HEALTH AND DISEASE MODERATOR: DR. MAHANTACHAR PRESENTER: DR. SPOORTHY

2. INTRODUCTION

3. The organs of multi cellular organisms consist of cells embedded in extra cellular matrix which execute specialist functions. During organogenesis, cells need to migrate to appropriate topographical location and stay there in order to maintain tissue integrity Following injury, cells need to migrate to damaged areas and undergo remodelling into the normal structure as a part of tissue repair

4. EXTRA CELLULAR MATRIX

5. The correct assembly of the ECM is necessary for: Direct morphogenesis during development Maintenance of tissue integrity and patterning in the adult Initiating cell signalling and events inside the cell

6. CELL MATRIX ATTACHMENT

7. The attachment of the cell to the matrix takes place by the formation of cell adhesion complexes These include intergrins and many cytoplasmic proteins These adhesion complexes attach to the actin cytoskeleton and help in attachment to the ECM Thus they help the cell to endure pulling forces without being ripped off the ECM

8. INTEGRINS

9. Cell adhesion to the ECM is mediated predominantly by the integrin family of heterodimeric transmembrane glycoproteins Upon ligand binding, integrins activate signal transduction pathways: The presence of integrins allows rapid and flexible responses to the events at cell surfaces

10. FOCAL ADHESIONS

11. Focal adhesions are specialized regions of plasma membrane where cells attaches to the extracellular matrix (ECM) These are large molecular complexes which are generated following interactions of integrins with ECM Integrins help in their clustering at the site of action

12. 60 Focal Adhesion proteins are identified in vertebrates Talin Vinculin Tensin Paxillin Focal adhesion kinase( FAK) Protein kinase C Src kinase

13. This supramolecular linkage appears to be critical in cytoskeleton organization and signal transduction, It is believed to participate in many biological events cell adhesion, migration, differentiation, proliferation, tissue development genesis of diseases

14. The life cycle of focal adhesions can be viewed: Assembly Maturation Disassembly

15. Tensin proteins are localised at focal adhesions These are among the molecules which act as molecular bridges between integrins and actin cytoskeleton The tensin family members play a pivotal role in key cellular processes including Adhesion Migration Proliferation Differentiation Apoptosis

16. WHAT IS TENSIN?

17. Tensin is a 220Kd Cytoplasmic phosphoprotein It is localised in specialised areas of plasma membrane called FOCAL ADHESIONS Evidence is now emerging that suggests Tensin is an important component linking the ECM, Actin cytoskeleton and Signal transduction

18. Identified in mid-1980s as an actin binding contaminant of an Vinculin preparation Initially characterised on chicken tensin protein using: SDS-PAGE Dynamic light scattering Gel filtration

19. Several groups reported that Tensin was localised to the ends of actin stress fibres at focal adhesions Tensin is phosphorylated on Tyrosine, Serine, Threonine residues Tyrosine phosphorylation of tensin is induced by ECM attachment PDGF treatment Thrombin or Angiotensin Oncogenes transformation: v-Src and Bcr/Abl

20. STRUCTURE OF TENSIN PROTEINS

21. The Tensin gene family consists of 4 members Tensin 1: TNS1 Tensin 2: TENC1 Tensin 3: TNS3 Tensin 4: TNS4 These genes encode multi domained cytoplasmic proteins

22. As a general structure of the Tensin family protein comprises of two domains. These domains bind to cytoskeletal proteins and signal transduction components. The Tensins have each been linked to multiple upstream and downstream signalling factors

23. The four members of the human tensin family display high sequence homology at the protein level All four tensins display significant homology at their C- terminus Tensins 1-3 have a high homologous N and C termini Divergent at their central regions

24. N- TERMINUS N-teminus comprises of: Two actin- binding domains(ABD) Region of homology to protein and lipid phosphatase(PTEN)

25. C-TERMINUS C-Terminus contains Src-homology 2: SH2 domain Phosphotyrosine binding domain: PTB

26. TENSIN 1

27. GENE Chromosome 2q 35-36 33 exons 1735 amino acid protein 185 KDa molecular mass Heart, skeletal muscles, kidney, lung

28. TEN1 has actin binding capabilities through distinct binding sites in the ABD Extra actin binding site is also present in the central region residues This central region shares high sequence homology to INSERTIN

29. C-TERMINUS: Tensin 1 contains SH2 regions similar to Tumour suppressor phosphatase and Tensin homologue (PTEN) This SH2 domain allows Tensin1 to bind to phosphorylated tyrosine residues on proteins such as FAK DLC 1 PI3 KINASE At both N and C termini, there are FAB domains which are required for localisation to focal adhesions

30. The PTB domains are known for binding phosphorylated tyrosine. Is is through this domain that Tensin 1 binds to the cytoplasmic tail of beta integrins independent of phosphorylation

31. TENSIN 2

32. GENE Chromosome 12q13 29 exons 1285 amino acid proteins 170KDa molecular weight

33. PROTEIN The central region of Tensin 2 is proline rich and can potentially act as a binding site for proteins containing Src homology(SH3) or WW domains This is the only member of Tensin family that has protein kinase C domain at N terminus

34. TENSIN 3

35. TENSIN 3- GENE Chromosome 7p12.3 1445 amino acid protein Molecular mass of 155KDa Placenta, Kidney

36. TENSIN 3-PROTEIN Tensin 3 contains 32 tyrosine residues, 13 of which are predicted to be potential sites of phosphorylation and possible candidates for signal transduction

37. TENSIN 4

38. TENSIN 4-GENE CTEN gene maps on chromosome 17q21.2 715 Amino acid protein 77KDa molecular mass Placenta, prostate tissues

39. CTEN- PROTEIN CTEN shows a high sequence homology at C terminus but it does not possess the N terminus This suggests that CTEN still contains the signalling component of other Tensin but lacks actin binding capabilities Thus it plays a novel role in cellular processes CTEN has also been detected in the nucleus

40. FUNCTIONAL ACTIVITY OF TENSIN

41. Exact individual role of Tensins are debatable In some circumstances can be tissue dependent Tensins role in health includes: Cell adhesion and motility Cell survival Apoptosis

42. ROLE OF CELL MIGRATION

43. Cell migration is a complex process that is essential to the diverse range of organisms In humans it is required for a number of physiological events and several pathological conditions The exact role of individual tensins are tissue dependent They are important in: Stabilising cell adhesion Regulating cell motility

44. PHYSIOLOGICAL EVENTS: Gastrulation Wound healing PATHOLOGICAL CONDITIONS Vascular diseases Osteoporosis Rheumatoid Arthritis CANCER

45. TENSIN 2 BINDS TO DLC 1 INHIBITS Rho-GTPase activity PROMOTES CELL MOTILITY

46. CTEN EGFR SIGNALLING TENSIN 3 DECREASES CTEN levels increase TENSIN switch Lacks N terminus NO BIND ACTIN STRESS FIBRES CELL MIGRATION

47. CELL SURVIVAL AND APOPTOSIS

48. Tensin Separates SH2/PTB from ABD Less of PI 3 mediated signal CASPASE 3 Integrins become detached

49. REGULATION OF TENSIN PROTEINS

50. Two main pathways EGFR signalling pathway Stat3 pathwathy Other factors have been reported to regulate Tensin proteins ECM PDGF Thrombin Angiotensin Bcr/Abl

51. Stat 3 Signalling Stat 3 signalling has been implicated as one of the upstream pathways regulating expression of Cten Stat 3 dependent over expression of Cten has been shown to disrupt cell adhesion and induce motility IL-6 has been shown to induce Cten via Stat 3

52. EGFR SIGNALLING Activation of EGFR signalling through EGF stimulation leads to: Tensin switch which with a decrease in Tensin 3 levels and an increase in CTEN The other tensins remain unaffected

53. The signalling pathway between EGFR and Tensin 3 and CTEN mostly involves KRAS/BRAF/ Mitogen activated protein kinase pathway Hence a mutation activation of KRAS and BRAF has been shown to up regulate Cten

54. TENSINS IN DISEASE

55. Several studies have highlighted alterations in the expression of the human tensins in the cancer Tensins are concerned with cell motility their involvement in carcinogenesis particularly the promotion of metastasis Role for Tensins in cancer has been most rigorously investigated for Tensin 3 and Cten Evidence clearly implicates each family member in disease progression

56. TENSIN 1 Expression of Tensin 1 was shown to be down- regulated in prostate and breast cancer cell lines Tensin 1 expression was induced in response to Resveratrol treatment in tensin negative or deficient erythroleukemic and breast cancer cell lines

57. TENSIN 2 Tensins 2 has been reported to be down regulated in cancers of kidney and lung Investigations in HCC revealed Tensin 2 to be over expressed in 46% of tumours compared to normal liver tissue

58. TENSIN 3 Tensin 3 reduced expression has been reported in the tumours of Thyroid, Kidney and Breast Forced expression of Tensin 3 led to decreased colony formation This supports the role of TEN 3 as a tumour suppressor This is consistent with the Tensin 3 ability to decrease cell migration in normal mammary epithelial cells

59. CTEN CTEN was originally identified as a tumour suppressor gene in prostate cancer It is also down regulated in tumours of kidney CTEN is normally not present in all tissues Elevated levels can be seen in tumours of Lung, Thymus, Colon, Breast and Pancreas This suggests that in these tumours it acts as an oncogene Greater levels are associated with advanced disease stage and metastasis

60. IHC analysis of normal and cancerous prostate tissue was done It revealed that CTEN expression was inversely correlated with prostate tumour grade CTEN is frequently over expressed in gastric cancer Tumours with higher CTEN expression displayed more aggressive behaviour

61. In breast cancer, CTEN expression has been shown to stimulate cell motility. CTEN was shown to be associated with tumour size, grade, nodal involvement and poor nottingham prognostic index CTEN expression was correlated with evidence of tumour progression in lung cancer and thymoma with metastasis to lymph node

62. CTEN interaction with beta- catenin also contributes to enhancing tumorigenicity Beta- catenin is found in adherent junctions, cytoplasm and nucleus In the nucleus, beta-catenin binds to TCF/LEF forming a transcriptional complex that turns on gene expression CTEN is reported to interact with beta-catenin only in the nucleus

63. MEDICAL APPLICATIONS

64. The renal histology of Tensin null mice revealed a typical triad of human nephronophthisis Tubular membrane disruption Tubular ectasia Interstitial inflammation Hence Tensin null mouse could be used as an animal model for human nephronophthisis or similar renal diseases

65. Tensins contains tri nucleotide CAG repeats Expansion of CAG repeats has been detected in many proteins that are relevant to inherited diseases It will be intriguing to know whether an expansion of tensin CAG repeats plays an important role in pathogenesis of human diseases

66. Analysis of Tensin expressions in human cancer patients and cell lines speculate that the loss of tensin expression may be an early event involved in cell transformation Tensins and its down streaming signalling molecules could be bio markers or therapeutic interventions in cancer

67. CONCLUSION

68. Tensins are emerging at the forefront as regulators of cell migration They have the ability to both bind actin cytoskeleton and mediate signal transduction events at focal adhesion regions This conveys their importance in regulating cell adhesion and migratory processes The Tensin family’s role in regulation of cell migration in turn extends to their involvement in cancer metastasis

69. The targeting of the cell migratory machinery by using tensin family gene presents an interesting therapeutic target for anti cancer therapies. Further characterisation may provide alternative targets in areas of need including EGFR inhibitor resistant tumours Over come problems associated with toxic anti- Src therapies under development

70. REFRENCES 23 Recent advances in histopathology Lo SH. Tensin. The international journal of biochemistry & cell biology. 2004 Jan 1;36(1):31-4. Huaiyang CH, ISHII A, Wai-Keung WO, CHEN LB, LO SH. Molecular characterization of human tensin. Biochemical Journal. 2000 Oct 15;351(2):403-11. Martuszewska D, Ljungberg B, Johansson M, Landberg G, Oslakovic C, Dahlbäck B, Hafizi S. Tensin3 is a negative regulator of cell migration and all four Tensin family members are downregulated in human kidney cancer. PloS one. 2009 Feb 4;4(2):e4350. Liao YC, Lo SH. Deleted in liver cancer-1 (DLC-1): a tumor suppressor not just for liver. The international journal of biochemistry & cell biology. 2008 Jan 1;40(5):843-7.

71. THANK YOU