Chemotherapy and Its Side Effects: Chapter 2 - Mitotic ihibitors (Tubule inhibitors)

Chapter 2

Anticancer Drugs - C. Mitotic inhibitors (Tubule inhibitors)

Mitosis is one step of the cell cycle (Fig. 1.8) in which a cell is divided into two identical cells and each has its own nucleus. A drug that inhibits mitosis (cell division) is referred to as a mitotic inhibitor, also referred to as a tubule inhibitor. Because microtubules play a very important role in mitosis, disruption of microtubules disrupts cell division thus achieving the anticancer effect.

Tubule inhibitors, including alkaloids and terpenoids, are usually derived from plants. They usually work by interfering with microtubule function or inhibiting the assembly of microtubules; microtubules are special proteins in tubular shape that are important components of cytoskeleton, which is a dynamic skeleton in cytoplasm that maintains cell shape and plays an important role in cellular division.  Examples of this type of drug include paclitaxel and vinblastine.

Fig. 1.8   Cell cycle

© Jiajiu Shaw, 2018

Disclaimer: This blog is written solely for informational purposes. It does not constitute the practice of any medical, nursing or other medical professional health care advice, diagnosis, or treatment. All contents posted are extracted from the book, "SIDE EFFECTS OF CHEMOTHERAPY AND RADIOTHERAPY", prepared by Dr. Jiajiu Shaw, Dr. Frederick Valeriote, and Dr. Ben Chen. 

Chemotherapy and Its Side Effects: Chapter 2

Chapter 2

Anticancer Drugs

Chemotherapy added a major new capability to the treatment of cancer beginning with the use of alkylating agents and anti-folates in the 1940s; it continues to expand today with anticancer agents specifically targeting single subcellular structures such as proteasomes or large enzyme groups like the kinase inhibitors and anti-metabolite agents.

In addition, medical oncologists who deliver these chemical agents have become an important leg of the present therapeutic triad, which also includes surgeons and radiotherapists. This triad defines the protocol for today’s impressive treatments.

For now, let’s focus on chemotherapeutic drugs. In addition to the conventional anticancer drugs, in the last twenty years or so, many novel anticancer drugs have been developed and approved by the Food and Drug Administration (FDA).

While chemotherapy drugs may be categorized in different ways. In this book, we attempt to divide anticancer drugs into several categories according to Table 1.1 although some drugs could be placed under several categories. Another type of therapy, gene therapy, will not be discussed here.

Based on the listing in Table 1.1, a number of representative anticancer drugs will be described and discussed in the following sections.

Table 1.1.  Categories of chemotherapeutic drugs

Category	Mechanism	Example
A.      Alkylating agents	Affect DNA or cell division	nitrogen mustard, cyclophosphamide, nitrosourea,  cisplatin, oxaliplatin
B.       Antimetabolites	Affect DNA or cell division	methotrexate, 5-fluorouracil
C.      Mitotic inhibitors (Tubule inhibitors)	Affect cell division	paclitaxel, vinblastine
D.      Antibiotics (Anthrocyclines)	Affect DNA or cell division	doxorubicin, dactinomycin, bleomycin
E.       Kinase modulators	Modulate cell behaviors	imatinib
F.       Hormones	Modulate cell behaviors	tamoxifen
G.      Monoclonal antibodies	Modulate cell behaviors	cetuximab, bevacizumab
H.      Other approaches	Modulate cell behaviors	antibody + chemotherapy

© Jiajiu Shaw, 2018

Disclaimer: This blog is written solely for informational purposes. It does not constitute the practice of any medical, nursing or other medical professional health care advice, diagnosis, or treatment. All contents posted are extracted from the book, "SIDE EFFECTS OF CHEMOTHERAPY AND RADIOTHERAPY", prepared by Dr. Jiajiu Shaw, Dr. Frederick Valeriote, and Dr. Ben Chen.