Introduction to Human Disease – Chemotherapy Drugs (Modes of Action)

A set of 50 flashcards covering the key concepts and drugs of chemotherapy, their mechanisms of action, and applications in medical treatment.

What therapeutic role does fluorine play in fluoro-uracil?

Fluorine provides a therapeutic antimetabolite effect.

How does Tamoxifen function in breast cancer treatment?

Tamoxifen acts as a selective estrogen receptor modulator.

What is the purpose of monoclonal antibody therapies in cancer treatment?

They act to activate the body’s immune response against tumors.

What does combination therapy R-CHOP consist of?

Rituximab, Cyclophosphamide, Vincristine, and Doxorubicin.

What type of DNA damage do alkylating agents cause?

Interstrand crosslinking and miscoding due to alkylation of nucleic acids.

Define the mechanism of action of Chlormethine.

Chlormethine operates via an SN2 mechanism of action.

Why are aromatic rings included in some Chlormethine analogues?

They are electron-withdrawing, lowering the nucleophilic strength of nitrogen.

What effect does the urethane group have on alkylating agents?

It lowers the nucleophilic strength of nitrogen, making the agent less reactive.

What is a significant feature of Cyclophosphamide?

It is a non-toxic pro-drug that gets activated in the body.

What role do Nitrosoureas play in cancer treatment?

They decompose to form alkylating agents in the body.

How does Busulfan act as an anticancer agent?

It causes interstrand crosslinking in DNA via an SN2 reaction.

What is the toxicity level of Mitomycin C as an anticancer drug?

Mitomycin C is one of the most toxic anticancer drugs in clinical use.

What is the significance of CC1065 in cancer treatment?

It is a naturally occurring agent with high alkylating activity.

How does Tamoxifen interact with the estrogen receptor?

It binds to the receptor without fully activating it, blocking 17β-estradiol binding.

Describe 5-Fluorouracil (5-FU) in terms of its function.

5-FU is an antimetabolite that inhibits thymidine biosynthesis.

What distinguishes monoclonal antibodies from normal antibodies in cancer treatment?

Monoclonal antibodies are specific to tumor-associated antigens.

What is the clinical use of Herceptin in cancer therapy?

Herceptin targets the HER-2 receptor in breast cancer treatment.

What type of antibody is Rituximab?

A chimeric monoclonal antibody targeting CD20 on B cells.

What does R-CHOP stand for in combination chemotherapy?

Rituximab, Cyclophosphamide, Vincristine, and Doxorubicin.

What is the role of Thymidylate Synthase in DNA synthesis?

It catalyzes the conversion of dUMP into dTMP.

What does the nitrogen of tetrahydrofolate do in the catalytic cycle of Thymidylate Synthase?

It removes a proton, enabling a reaction that allows thymidylate to exit.

What is the outcome of 5-Fluorouracil inhibiting Thymidylate Synthase?

It stops DNA synthesis by preventing the conversion of dUMP to dTMP.

What is the inactive form of Cyclophosphamide until it is metabolized?

Cyclophosphamide is a pro-drug that must be activated.

Describe how alkylating agents lead to abnormal base pairing in DNA.

Alkylating agents modify nucleobases, causing incorrect pairing during replication.

How does the alkylating action of mitomycin C compare to cisplatin?

CC1065 is 1000 times more active than cisplatin in vitro for alkylation.

Why is the presence of fluorine significant in the structure of 5-Fluorouracil?

Fluorine prevents the biosynthesis of thymidine from uracil.

What type of cancers can monoclonal antibodies treat effectively?

They are used in treating breast cancers, colorectal cancers, and lymphomas.

What is the primary targeted receptor in HER-2 positive breast cancer?

The HER-2 growth factor receptor.

What adverse effect is associated with Cyclophosphamide's by-product?

Acrolein by-product is associated with toxicity.

Why is 5-Fluorouracil considered preferential for certain tumor cells?

Some tumor cells preferentially use uracil for synthesizing thymidine.

What does Tamoxifen significantly inhibit in estrogen-dependent tumors?

It inhibits the action of estrogens by blocking their receptors.

What is the effect of ultraviolet light on alkylation-induced DNA damage?

It can cause thymine dimers, compounding DNA damage.

Why is the structure of paclitaxel not required for understanding its effect when combined with Herceptin?

The action focus is on its use with Herceptin, not the structure.

What is the mechanism behind the action of alkylating agents like Busulfan?

They form cross-links between DNA strands, inhibiting replication.

What is a common side effect of alkylating agents?

They can cause damage not only to cancer cells but also to healthy cells.

What are chimeric antibodies?

Proteins created by combining parts from two or more genes.

How often is the R-CHOP regimen administered during treatment?

Treatments are separated by 21 days.

How does the body recognize cancer cells regarding monoclonal antibodies?

Cancer cells express distinctive antigens in higher levels than normal cells.

What is the purpose of the SN2 reaction in the context of chlormethine?

The SN2 reaction is crucial for its mechanism of action as an alkylator.

What is the function of the estramustine group in its mechanism?

It enhances the permeation of alkylating agents through cell membranes.