2.5 Transplantable tumors
A. Heterotopic transplantation B. Orthotopic transplantation2.5.1 Syngeneic models2.5.1.1 Leukemia 1210 (L1210) 2.5.1.2 Lewis Lung Carcinoma model 2.5.1.3 Ehrlich Ascites carcinoma2.5.2 Xenograft models2.5.2.1 Subcutaneous implantation 2.5.2.2 Renal Subcapsular (RSC) 2.5.2.3 Intraperitoneal Microencapsulated Tumor Assay 2.5.2.4 Orthotopic Xenograft Model2.6 Genetically Engineered Mouse Models (GEMs)2.6.1 Transgenic Mice 2.6.1.1 TRAMP transgenic mice 2.6.1.2 p53+/- Wnt-1 transgenic mice 2.6.1.3 Apc Deficient mice2.6.2 Knockout Mice
  1. The Nkx 3.1 knockout mice
  2. Homozygous p53 knockout mice
  3. Brca1 conditional knockout model
In vitro models for angiogenesis research
3.1 Two-Dimensional angiogenesis models 3.1.1 Boyden chamber assay for endothelial cell migration 3.1.2 Scratch wound assay for endothelial cell migration 3.2 Three-Dimensional spherical-shaped angiogenesis models
Micro carrier assay
3.2.1 Three-Dimensional plate-shaped angiogenesis models 3.2.2 Three-Dimensional basement membrane assay
  1. Apoptosis assay (Annexin V-FITC)
  2. Brine shrimp lethality bioassay
  3. Cell viability and cytotoxicity assays
  4. Dye exclusion assay
  5. Colorimetric assay
  6. Fluorometric assay
  7. Luminometric assay
  8. Metastasis
  9. Conclusion and future perspectives
  10. References
Introduction
Globally, cancer is the second-highest mortality rate after cardiovascular diseases(Manglani et al., 2014);in 2020, there will be 19.4 million new cases and 10.0 million deaths from the disease. Over 13 million people are expected to die from cancer worldwide in 2030(Sung et al., 2021). Men can develop colorectal, liver, lung, stomach, prostate, and lung cancer, while women can develop breast, cervix, lung, thyroid, and 36 other types of cancer(Poonam and Chandana, 2015). The inherent mechanisms of the development of resistance to therapeutic approaches make treating cancer a difficult task.
Conventional treatment modalities for cancer management include chemotherapy, radiation therapy, and surgery(Khan et al., 2020).The Radiation therapy (usually called radiotherapy) is a type of cancer therapy intended to kill cancer cells and to decrease tumours by using intense radiation doses. In addition to damaging nearby healthy cells, radiotherapy can also kill or slow the growth of cancer cells. Unintended consequences may result from harm to healthy cells. Fatigue, nausea, abdominal discomfort, and other side effects of radiotherapy(Nounou et al., 2015).
Surgery is the commonest treatment modality used for localized tumors. This approach is associated with several side effects such as pain, discomfort, bleeding and surgical-wound complications(Nounou et al., 2015). Chemotherapy (often called chemotherapy) is a cancer therapy which uses drugs to kill cancer cells. Chemotherapy does not only kill or reduce cancer cell growth, it also kills or slows healthy cell growth. The side effects of cell damage include mouth sores, nausea and hair loss(DeVita and Chu, 2008).
Major risk factors contributing to the carcinogenesis process include genetic predisposition, alcohol and tobacco consumption, sedentary lifestyle/lack of physical activity, dietary habits, environmental influence, exposure to biological carcinogenic agents (EBV, HPV etc.) and exposure to various physical and chemical carcinogenic molecules (Saini et al., 2020).
Through metabolic activation, carcinogens can become directly or indirectly transformed into electrophilic molecules that interact with DNA. Different cellular responses may occur depending on the degree of cell injury (formation of DNA-adducts), in cases of low damage, DNA repair may be used to restore normal function, in cases of excessive damage, cells may experience programmed cell death. However, under the pressure of cellular replication, damaged DNA permits cell mutation, as a result, initiated cells carry permanent and heritable DNA alterations that may predispose to the development of cancer. (Figure-1).