Tumor Suppressor Gene Animation

Tumor-suppressor genes encode proteins that inhibit uncontrolled cell proliferation, acting as protective mechanisms against cancer. When these genes acquire loss-of-function mutations, their regulatory control weakens, leading to unrestricted cell division and tumor formation.

Classes of Tumor-Suppressor Proteins

1️⃣ Cell Cycle Regulators

• Control cell cycle progression, ensuring orderly division.
• Examples :
  • p16 (CDKN2A) : Inhibits cyclin-dependent kinases (CDKs) to halt cell cycle progression.
  • Rb (Retinoblastoma protein) : Blocks transcription factors essential for G1 to S-phase transition.

2️⃣ Receptors & Signal Transducers for Growth Inhibition

• Mediate responses to inhibitory growth factors, preventing excessive proliferation.
• Examples :
  • TGF-β (Transforming Growth Factor Beta) : Suppresses epithelial cell proliferation.
  • Patched (PTCH1, Hedgehog pathway receptor) : Regulates developmental signaling.

3️⃣ Checkpoint-Control Proteins

• Detect DNA damage and arrest the cell cycle to allow repair.
• Examples :
  • p53 (TP53 gene) : Activates DNA repair mechanisms, induces apoptosis if damage is irreparable.

4️⃣ Pro-Apoptotic Proteins

• Trigger programmed cell death (apoptosis) in response to severe cellular damage.
• Examples :
  • BAX and BAD : Promote mitochondrial-mediated apoptosis.

5️⃣ DNA Repair Enzymes

• Maintain genomic stability by repairing DNA damage before mutations accumulate.
• Examples :
  • BRCA1 & BRCA2 : Repair double-strand DNA breaks, mutations in these genes are linked to breast and ovarian cancers.

Tumor-Suppressor Genes in Cancer Research

Loss or mutation of tumor-suppressor genes contributes to cancer progression. Targeted therapies and gene-editing techniques, such as CRISPR and RNA-based therapeutics, are being explored to restore their function.