Cisplatin

Definition

Cisplatin is a platinum-based chemotherapy drug used to treat a variety of cancers. It is a coordination complex that forms covalent bonds with DNA, leading to cell death and inhibition of tumor growth.

5 Must Know Facts For Your Next Test

1. Cisplatin is a square-planar coordination complex with a central platinum(II) ion bonded to two chloride ligands and two ammonia ligands.
2. Cisplatin enters the cell and forms covalent bonds with the N7 positions of guanine and adenine bases in DNA, leading to DNA cross-linking and inhibition of DNA replication and transcription.
3. The binding of cisplatin to DNA triggers a series of cellular responses, including activation of DNA repair mechanisms and, if the damage is irreparable, programmed cell death (apoptosis).
4. Cisplatin is effective against a wide range of solid tumors, including testicular, ovarian, bladder, head and neck, and lung cancers.
5. The use of cisplatin is often limited by its side effects, such as nephrotoxicity, neurotoxicity, and ototoxicity, which can be managed through hydration and the use of protective agents.

Review Questions

• Describe the structure and bonding of the cisplatin coordination complex.
  • Cisplatin is a square-planar coordination complex with a central platinum(II) ion. The platinum ion is bonded to two chloride ligands and two ammonia ligands in a covalent manner. The square-planar geometry is a characteristic feature of d$^8$ transition metal complexes, such as platinum(II) complexes. The covalent bonds between the platinum ion and the ligands are formed by the sharing of electron pairs, which contributes to the stability and reactivity of the cisplatin complex.
• Explain how cisplatin interacts with DNA and the resulting cellular effects.
  • Cisplatin enters the cell and forms covalent bonds with the N7 positions of guanine and adenine bases in DNA. This DNA cross-linking disrupts the normal structure and function of DNA, leading to the inhibition of DNA replication and transcription. The binding of cisplatin to DNA triggers a series of cellular responses, including the activation of DNA repair mechanisms. If the DNA damage is irreparable, the cell undergoes programmed cell death (apoptosis). These cellular effects of cisplatin are the basis for its use as an effective chemotherapeutic agent against a variety of solid tumors.
• Discuss the therapeutic applications and limitations of cisplatin in cancer treatment.
  • Cisplatin is a widely used chemotherapeutic agent effective against a range of solid tumors, including testicular, ovarian, bladder, head and neck, and lung cancers. Its mechanism of action, involving the formation of covalent bonds with DNA and the subsequent disruption of cellular processes, makes it a potent anti-cancer drug. However, the use of cisplatin is often limited by its side effects, such as nephrotoxicity, neurotoxicity, and ototoxicity. These side effects can be managed through hydration and the use of protective agents, but they can still pose significant challenges in clinical practice. Despite these limitations, cisplatin remains an important and widely used chemotherapeutic agent in the treatment of various cancers, highlighting the need for ongoing research to improve its therapeutic efficacy and reduce its side effects.

Related terms

Coordination Complex: A coordination complex is a central metal atom or ion bonded to surrounding ligands, which can be atoms, ions, or molecules.

Covalent Bond:

A covalent bond is a chemical bond formed by the sharing of one or more pairs of electrons between two atoms.

Ligand:

A ligand is an atom, ion, or molecule that binds to a central metal atom or ion, forming a coordination complex.