How does taxol worth? (see details)?

Question

There's something in my science textbook about Taxol, a substance taken from the bark of some sorta yew tree yadda yadda yadda, and it's given to cancer patient. It supposedly creates a sort of "cage" around cancer cells to stop them from reproducing, and reduces tumors this way.

I thought a tumor was a mass of cancer cells that formed together. Does the taxol "cage" form around the whole tumor or individual cancer cells? But if taxol just stops the cells from reproducing, how does it make a mass of them smaller, or how does it form around every tumor cell if it's one big mass?

Am I wrong about everything here, or have I just forgotten one thing? Is this just a big deal about a simple answer? Please reply if you know, I'm very confused over here!

Answer 1

Taxol is a new concept in the treatment of cancer because it acts on the microtubules found in cells, whereas earlier anti cancer drugs act on the DNA of the cancer cells. Microtubules are responsible for keeping the shape of the cell by forming a structure called the cytoskeleton. They are also involved in controlling the positions of chromosomes during cell division.

Molecules of a cellular protein called tubulin link together to form microtubules, but in the presence of Taxol, these microtubules are shorter than normal and very stable. Due to this, the microtubules cannot carry out their function during cell division. The cell becomes congested with these microtubules and therefore the cycle of cell division (mitosis) is disrupted and cell death occurs.

Answer 2

The mechanism through which Taxol and other taxanes achieve their antitumour activity is unique. Virtually all cells replicate using mitosis. Taxol inhibits this by binding to a protein called tubulin in cells resulting in the formation of stable, non-functional microtubule bundles (Crown et al, 2000). These are normally essential in mitosis, and so, because of the actions of Taxol, cells would be unable to replicate. The drug is targeted at tumour cells but also affects other cells of the body. Taxanes are also found to induce apoptosis, a process through which cells die in a controlled manner, and may also have anti-angiogenic properties, useful as it prevents a blood supply forming to the site of the cancer.

Answer 3

Taxol or paclitaxel interferes with the normal function of microtubule growth. It arrests their function by hyper-stabilizing their structure. This destroys the cell's ability to use its cytoskeleton in a flexible manner. Specifically, paclitaxel binds to the β subunit of tubulin. Tubulin is the "building block" of mictotubules, and the binding of paclitxel locks these building blocks in place. The resulting microtubule/paclitaxel complex does not have the ability to disassemble. This adversely affects cell function because the shortening and lengthening of microtubules (termed dynamic instability) is necessary for their function as a transportation highway for the cell.