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Anti- Tumor assay / Screening of Anticancer Drugs

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Anti- Tumor assay / Screening of Anticancer Drugs

  1. 1. Anti-Tumor Assay PRESENTED BY : PRATIK UMESH PARIKH MASTER OF PHARMAC Y (PHARMAC EU TIC AL BIOTECHNOLO G Y) PRESENTEDBY : PRATIKUMESH PARIKH GUIDED BY : DR. S. B. DAHIKAR SIR CELLULAR & MOLECULAR BIOLOGY
  2. 2. Contents : Introduction of cancer Need for novel anti cancer drugs In-vitro assay In- Vivo assay Reference PRESENTEDBY : PRATIKUMESH PARIKH
  3. 3. Introduction of Cancer: •Cancer is a disease which is characterized by uncontrolled proliferation of cells that have transformed from the normal cells of the body. • Factors: External Factors – chemicals, radiation, bacteria, viruses, and lifestyle Internal Factors – hormones, immune conditions, and inherited mutations PRESENTEDBY : PRATIKUMESH PARIKH
  4. 4. • Although 92 approved anticancer drugs are available today for the treatment of more than 200 different tumor entities, effective therapies for most of these tumors are lacking. • They are mostly cytotoxic in nature and act by a very limited number of molecular mechanisms. • Thus, the need for novel drugs to treat malignant disease requiring systemic therapy is still pressing. • A pre selection, called the screening process, is therefore required. • The goal of screening assay is to test the ability of a compound to kill cells, it should be able to discriminate b/t replicating & non replicating cell PRESENTEDBY : PRATIKUMESH PARIKH
  5. 5. Need for Novel Anti-Cancer Drugs: •Development of multidrug resistance in patients. • Long-term treatment with cancer drugs is also associated with severe side effects. • Cytotoxic drugs have the potential to be very harmful to the body unless they are very specific to cancer cells. • New drugs that will be more selective for cancer cells PRESENTEDBY : PRATIKUMESH PARIKH
  6. 6. Anti-tumor Assay models: PRESENTEDBY : PRATIKUMESH PARIKH In-vitro Assay In-vivo Assay
  7. 7. In-Vitro Methods: 1. Tetrazolium salt assay 2. Sulphorhodamine B assay 3. 3H-Thymidine uptake assay 4. Fluorescence 5. Dye exclusion test 6. Clonogenic test 7. Cell counting assay 8. Morphological assay PRESENTEDBY : PRATIKUMESH PARIKH
  8. 8. 1. Tetrazolium salt assay •This assay is a sensitive, quantitative and reliable colorimetric assay that measures viability, proliferation and activation of cells. • The assay is based on the capacity of mitochondrial dehydrogenase enzymes in living cells to convert the yellow water-soluble substrate 3-(4,5-dimethylthiazol- 2yl)-2,5-diphenyl tetrazolium bromide (MTT) into a dark blue formazan product which is insoluble in water. PRESENTEDBY : PRATIKUMESH PARIKH
  9. 9. • The amount of formazan produced is directly proportional to the cell number in range of cell lines PRESENTEDBY : PRATIKUMESH PARIKH
  10. 10. 2. Sulphorhodamine B assay PRINCIPLE • Ability of SRB to bind to protein components of cells fixed to tissue culture plates by TCA •SRB : bright pink aminoxanthine dye with 2 sulfonic groups •Binding of SRB is stoichiometric •Amount of dye extracted from stained cells proportional to the cell mass PRESENTEDBY : PRATIKUMESH PARIKH
  11. 11. Method: • The Sulphorhodamine B assay measures whole-culture protein content, which should be proportional to the cell number. • Cell culture are stained with a protein staining dye, Sulphorhodamine B. • SRB is a bright pink anionic dye that binds to basic amino acid of cell. • Unbound dye is then removed by washing with acetic acid. • During the dead cell either lyse or are lost during procedure, the amount of SRB binding is proportional to the number of live cells left in a culture after drug exposure. PRESENTEDBY : PRATIKUMESH PARIKH
  12. 12. 3. 3H-Thymidine uptake assay PRINCIPLE • 3H- thymidine incorporated into new strands of DNA •Scintillation beta- counter used to measure radioactivity in DNA recovered from the cells in order to determine extent of cell division occurred in response to test agent • Direct measures of proliferation PRESENTEDBY : PRATIKUMESH PARIKH
  13. 13. Method: • Tumor cell suspensions exposed to the drug for 5 days •3H- thymidine added during final 48 hrs •Replicating cells incorporate 3H- thymidine into their DNA •Determined either by autoradiography / liquid scintillation counter •Generate DNA histograms ploidy status of cells •Non replicating or dead cells will not be counted PRESENTEDBY : PRATIKUMESH PARIKH
  14. 14. 4. Dye exclusion test • To determine cell viability in which dilute solution of dyes ( trypan blue, eosin Y, nigrosin, Alcian blue) is mixed with suspensions of cells • Cells exclude dye :- alive • Cells that stain:- dead • Indicate structural integrity of cell membrane • Weisenthal and colleagues used novel combination of fast green dye & eosin – hematoxylin with more promising results, in patients with hematological malignancies (CLL) PRESENTEDBY : PRATIKUMESH PARIKH
  15. 15. 5. Cologenic Assay • In-vitro cell survival assay based on the ability of single cell to grow into a colony •Assay tests every cells in population for its ability to undergo unlimited division •Imp. for drugs act by arresting check points in cell cycle PRESENTEDBY : PRATIKUMESH PARIKH
  16. 16. In-Vivo Methods: 1. Carcinogen induced models 2. Viral infection models 3. Transplantation Models 4. Genetically Engineered Mouse Models 5. In vivo hollow fibre assay PRESENTEDBY : PRATIKUMESH PARIKH
  17. 17. 1. Carcinogen Induced Model DMBA induced mouse skin papillomas •Two stage experimental carcinogenesis › Initiator – DMBA(dimethylbenz[a]anthracene), › Promotor – TPA (12-O-tetradecanoyl-phorbol-13acetate) •Mice : Single dose – 2.5 µg of DMBA , 5 to 10 μg of TPA in 0.2 ml of acetone twice weekly. •Papilloma begins to appear after 8 to 10 weaks •Tumor incidence & multiplicity of treatment group is compared with DMBA control group PRESENTEDBY : PRATIKUMESH PARIKH
  18. 18. PRESENTEDBY : PRATIKUMESH PARIKH Control Model DMBA Model
  19. 19. Method  Mice are topically applied a single dose of 2.5 µg DMBA in acetone, followed by 5-10 µg of TPA in 0.2 ml acetone twice weekly on the same site starting one week after DMBA application.  Percent tumor incidence and multiplicity of treatment groups is compared with DMBA control group.  Drug under test can be administered either topically or oral route.  The tumor incidence in this model is usually about 100% in DMBA controls.  In repeated topical application of DMBA Alone has also been shown to induced carcinogenesis.  Drug efficacy is measured as percent reduction in carcinoma incidence, compared with that of carcinogen control. PRESENTEDBY : PRATIKUMESH PARIKH
  20. 20. 2) MNU induced rat mammary gland CA • MNU Induces hormone dependent tumors. • Single i.v of 50 mg/kg of methylnitrosourea(MNU) given to 50 days old Sprague-Dawley rats. • Adenocarcinoma will be produced within 180 days of post carcinogen in 75 to 95% cases • Drug efficacy is measured • Drawback – cannot detect inhibition of carcinogen activation • Better model for human breast cancer PRESENTEDBY : PRATIKUMESH PARIKH
  21. 21. 3) Method Involving cell line : • Specified number of particular cell line inoculated into sensitive mouse strain • Tumors develop rapidly thus time saving • Effective drug retard tumor growth and increase life span of animal • L-1210, P-388, B-16 cell lines- host mouse strain BDF1 • Sarcoma-180 – Swiss albino mouse PRESENTEDBY : PRATIKUMESH PARIKH
  22. 22. PRESENTEDBY : PRATIKUMESH PARIKH
  23. 23. 4) Xenografts : • Human tumors(lung, breast, colon, ovary, brain, HCC) are optimized in mouse cell lines • Directly injected below the skin of the mouse • Drugs showing activity in hollow fiber model are administered at various dosages • Compounds that kill or slowdown growth of specific tumor with minimal toxicity- proceed to next stage of testing • 1. Spheroid culture of LuCap 147-induced prostate cancer model • 2.Integration free-induced pluripotent stem cell model high throughput screening drug induced cell cycle arrest Apoptosis can be demonstrated in spheroid cultures PRESENTEDBY : PRATIKUMESH PARIKH
  24. 24. 5) EAC Cells by Liquid Tumour Model (Ehrlich Ascites Carcinoma) on (Swiss albino mice) EXPERIMENTAL PROTOCOL • Induction of ascitic carcinoma - The ascitic tumor bearing mice (donor) were used . The ascitic fluid was drawn using an 18 gauge needle into a sterile syringe. A small amount of tumor fluid was tested for microbial contamination. Tumor viability was determined by tryphan blue exclusion test and cells were counted using haemocytometer. The ascitic fluid was suitably diluted with saline to get a concentration of 10 million cells/ml of tumor cell suspension. 250 µl of this fluid was injected in each mouse by i.p. route to obtain ascitic tumor PRESENTEDBY : PRATIKUMESH PARIKH
  25. 25. • The mice were weighed on the day of tumor inoculation and then for each three days. • Cisplatin was injected on two alternative days 1st and 3rd day after tumor inoculation (intraperitoneally). • The drugs were administered after 24 hours of tumor inoculation and were admistered till 9th day intraperitoneally. • On 15th day blood was collected from the animal through the retroorbital plexus to determine the heamatological parameters and lipid profil PRESENTEDBY : PRATIKUMESH PARIKH
  26. 26. Parameters monitored : 1) % Decrease in weight variation compared to control. 2) Median survival time (MST) and percentage increase in lifespan (%ILS). 3) Mean survival time (MEST) and percentage increase in lifespan (%ILS). 4) Cell viability test. (% Survivors of malignant cells in ascitic fluid). 5) Haematological parameters a. Total W.B.C. and differential leukocyte counts. b. Total R.B.C. and Hemoglobin content. PRESENTEDBY : PRATIKUMESH PARIKH
  27. 27. Cell viability test : • Tryphan blue exclusion test is based on the principle that the living cell membrane has the ability to prevent the entry of the dye. Hence they remain unstained and can be easily distinguished from the dead cells, which take the dye. • On day15 after tumor inoculation 0.1 ml of ascitic fluid was taped and subjected to Tryphan Blue Assay to assess the number of viable tumor cells • Equal volumes of EAC cell suspension and 0.1% Tryphan blue solution were mixed thoroughly. The diluted suspension was charged into Haemocytometer • The viable (unstained) were counted in WBC chamber under microscope and mean number of cells in 4 chambers were counted. •Total number of cells =Mean number of cells x dilution factor x104 PRESENTEDBY : PRATIKUMESH PARIKH
  28. 28. Reference : 1. Drug screening methods by S K Gupta, 3rd edition, page no: 170-187 2. Drug discovery and evaluation: pharmacological assays by Hans Gerhard Vogel , 3rd edition 3. Stephen Hus, Fu Xin Yu et al , A mechanism based in in-vitro anticancer drug screening approach by , 46 PRESENTEDBY : PRATIKUMESH PARIKH
  29. 29. PRESENTEDBY : PRATIKUMESH PARIKH

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