Structure and Characteristics of Normal and Cancerous cells.pptx

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1. Structure and Characteristics of Normal and Cancerous cells

2. Objectives At the end of this session students will be able to : Explain the normal cell structure Detail on cell cycle Enlist the characteristics of normal cells Define Cancer Describe Progression of cancer Explain benign and malignant tumor and their differences Differentiate between Normal cells and cancer cells

3. Cell Structure

4. Cell Cycle

5. Characteristics of Normal cells These ‘normal’ cells act as the body’s basic building blocks. Normal cells control their growth using external signals, meaning they only grow and divide when required. They undergo programmed cell death (apoptosis) as part of normal development, to maintain tissue homeostasis, and in response to unrepairable damage. They ‘stick together’ by maintaining selective adhesions that they progressively adjust which ensures they remain in their intended location. Normal cells differentiate into specialized cells with specific functions meaning they can adopt different physical characteristics despite having the same genome.

6. What is CANCER? An uncontrolled division of abnormal cells in a part of the body is called cancer. Abnormal cells divide without control and can invade nearby tissues. Loss of Cell-cycle Control. Before a cell divides, the DNA is checked to make sure it has replicated correctly. (If DNA does not copy itself correctly, a gene mutation occurs.

7. Essential alterations in cell physiology that characterized malignancy In 2000 cancer biologists Robert Weinberg and Douglas Hanahan published an article entitled " The Hallmarks of Cancer.“ Self-sufficiency in growth signals: cancer cells acquire an autonomous drive to proliferate - pathological mitosis - by virtue of the activation of oncogenes such as ras or myc. Insensitivity to growth-inhibitory (antigrowth) signals: cancer cells inactivate tumor suppressor genes, such as Rb , that normally inhibit growth. Evasion of programmed cell death (apoptosis): cancer cells suppress and inactivate genes and pathways that normally enable cells to die.

8. Essential alterations in cell physiology that characterized malignancy In 2000 cancer biologists Robert Weinberg and Douglas Hanahan published an article entitled " The Hallmarks of Cancer.“ Limitless replication potential: cancer cells activate specific gene pathways that render them immortal even after generations of growth. Sustained angiogenesis: cancer cells acquire the capacity to draw out their own supply of blood and blood vessels - tumor angiogenesis. Tissue invasion and metastasis: cancer cells acquire the capacity to migrate to other organs, invade other tissues, and colonize these organs, resulting in their spread throughout the body.

9. What is Tumor ? A tumor is an abnormal growth of body tissue. Tumors can be cancerous (malignant) or noncancerous (benign). Benign tumor : These are not cancerous. They either cannot spread or grow, or they do so very slowly. If a doctor removes them, they do not generally return. Malignant: Malignant tumors are cancerous. The cells can grow and spread to other parts of the body.

10. Normal Cell vs Cancer Cell – The Key Differences Cell shape cancer cells are misshapen and irregular in shape. Normal cell of same cell type will look extremely similar, maintaining a uniform shape. But cancer cells differ.

11. Normal Cell vs Cancer Cell – The Key Differences Nucleus In normal cells the nucleus has a smooth appearance and maintains a uniform, spheroid shape. Cancer cell nuclei are frequently misshapen and bulges known as “blebs” .

12. Normal Cell vs Cancer Cell – The Key Differences Chromatin The fine, evenly distributed chromatin found in normal cells. coarse, chromatin are found in cancer cells aggregating into irregular clumps that vary in both size and shape.

13. Normal Cell vs Cancer Cell – The Key Differences Nucleolus The nucleolus becomes increasingly enlarged and more irregular in cancer cells – cells can have multiple nucleoli within the nucleus.

14. Normal Cell vs Cancer Cell – The Key Differences Blood supply Angiogenesis is a vital process in normal cells that occurs during development, growth, and wound healing. Tumors have the ability to secrete chemical signals that stimulates angiogenesis

15. Normal cell Vs Cancer cells Features Normal Cell Cancer Cell Cell shape Uniform Irregular Nucleus Spheroid shape, single nucleus Irregular shape, multi-nucleation common Chromatin Fine, evenly distributed Coarse, aggregated Nucleolus Single, inconspicuous nucleolus Multiple, enlarged nucleoli Cytoplasm Large cytoplasmic volume Small cytoplasmic volume Growth Controlled Uncontrolled Maturation Mature into specialized cells Remain immature and undifferentiated Blood supply Normal angiogenesis (occurs during development/ healing) Tumor -induced angiogenesis Oxygen Usually aerobic Anerobic resp.

16. Normal cell Vs Cancer cells Features Normal Cell Cancer Cell Location Remain in their intended location Can spread to different locations in the body (metastasis) Specialization and maturity Mature into distinct cell types with specific functions; cell division stops once they become fully differentiated. Do not specialize or differentiate; divide quickly before maturing and remain immature and undifferentiated. Growth Factor Proteins Stop growing and dividing when they stop producing growth factors May produce their own growth factors that stimulate reproduction Apoptosis (programmed cell death) Occurs when a cell is no longer needed, grows old or when DNA damage cannot be repaired. Do not repair themselves and do not undergo apoptosis, and thus live longer.

17. References Normal and Cancer Cells Structure: Image Details - NCI Visuals Online. (2018). Retrieved from https://visualsonline.cancer.gov/details.cfm?imageid=2512 Nandini , D.B. (2017) Cancer Cell Nucleus: An Insight. J Mol Biomark Diagn S2:026. doi:10.4172/2155-9929.S2-026 Papetti , M., & Herman, I. (2002). Mechanisms of normal and tumor -derived angiogenesis. American Journal Of Physiology-Cell Physiology, 282(5), C947-C970. doi : 10.1152/ajpcell.00389.2001 Eales , K., Hollinshead , K., & Tennant, D. (2016). Hypoxia and metabolic adaptation of cancer cells. Oncogenesis , 5(1), e190-e190. doi : 10.1038/oncsis.2015.50 Cancer cells. (2018). Cancer Research UK. Retrieved from https://www.cancerresearchuk.org/about-cancer/what-is-cancer/how-cancer-starts/cancer-cells