Screening methods of Cancer


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Screening methods of Cancer

  1. 1. SCREENING METHODS OF CANCER By Arijit Chakraborty M.Pharm (Pharmacology)
  2. 2. What is Cancer? Cancer is a disease which characterized by uncontrolled proliferation of cell that have transformed from the normal cells of the body. CAUSE: • External Factors – chemicals, radiation, viruses, and lifestyle • Internal Factors – hormones, immune conditions, and inherited mutations • Theories – Cellular change/mutation theories – Carcinogens – Oncogenes/ protooncogenes
  3. 3. Factors Believed to Contribute to Global Causes of Cancer
  4. 4. Methods In Vitro: 1. Tetrazolium salt assay. 2. Sulphorhodamine B assay. 3. 3H-Thymidine uptake. 4. Dry exclusion test. 5. Clonogenic test. 6. Cell counting assay. In Vivo: 1. DMBA-induced Mouse Skin Papillomas. 2. DMBA-induced Rat Mammary Gland Carcinogenic. 3. MNU-induced Tracheal Squamous cell Carcinoma in Hamster.
  5. 5. Tetrazolium salt assay (IN VITRO) It is performed to determine the Enzymatic properties. The cell from a particular cell live when in log phase a trysinized. It is counted in a homocytometer and adjusted multiwell plates (96 well plates) The cells are treated with a various concentration of drug for specified duration
  6. 6. CONT…. After MIT dye is added in each well and plates are incubated at 37 C for 4 hrs in a CO2 incubator. The plates are taken out the incubator and dark-blue colored formazan crystal are thoroughly dissolved in DMSO in room temperature. The plates are then read on a ELISA reader at 570 nm. To calculate the percent cell viability with respect to control is calculated using, % cell viability =(OD of treated cells/ OD of control
  7. 7. Sulphorhodamine B Assay 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.
  8. 8. DMBA-induced Mouse Skin Papillomas This is a classical to stage experimental carcinogenesis model. Mouse skin is generally most sensitive to epidermal carcinogenesis. SENCAR mice are highly sensitive to DMBA induced skin tumor. DMBA acts as a inhibitor and 12- O- tetradecanoyl- pharbol- 13 acetate is used as a promoter to induce skin papillomas and Squamous cell carcinomas.
  9. 9. CONT… Mice are topically applied a single dose of 2.5 µg DMBA in acetone on the shared back, 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% DMBA controls.
  10. 10. DMBA-induced Rat Mammary Gland Carcinogenic Female Sprague-Dawley are use for this method. Rats are given single intragastric injection of 12 mg/kg DMBA at 50 days of age. This dose results in 80-100% incidence of total mammary tumors within 120 days post carcinogen.
  11. 11. This model can detect the agents/drugs inhibiting carcinogen activation. DNBA produced capsulated tumors with high incidence. Drug efficacy is measured as percent reduction in adenoma incidence, percent increase in adenocarcinoma latency compared with that of carcinogen control.