化疗药物如何起效 How Does Chemotherapy Work

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During World War I, one of the horrors of trench warfare was a poisonous yellow cloud called mustard gas. For those unlucky enough to be exposed, it made the air impossible to breathe, burned their eyes, and caused huge blisters on exposed skin.

Scientists tried desperately to develop an antidote to this vicious weapon of war. In the process they discovered the gas was irrevocably damaging the bone marrow of affected soldiershalting its ability to make blood cells.

Despite these awful effects, it gave scientists an idea. Cancer cells share a characteristic with bone marrow: both replicate rapidly.

So could one of the atrocities of war become a champion in the fight against cancer? Researchers in the 1930s investigated this idea by injecting compounds derived from mustard gas into the veins of cancer patients.

It took time and trial and error to find treatments that did more good than harm, but by the end of World War II, they discovered what became known as the first chemotherapy drugs. Today, there are more than 100.

Chemotherapy drugs are delivered through pills and injections and use "cytotoxic agents," which means compounds that are toxic to living cells. Essentially, these medicines cause some level of harm to all cells in the bodyeven healthy ones.

But they reserve their most powerful effects for rapidly-dividing cells, which is precisely the hallmark of cancer. Take, for example, those first chemotherapy drugs, which are still used today and are called alkylating agents.

They're injected into the bloodstream, which delivers them to cells all over the body. Once inside, when the cell exposes its DNA in order to copy it, they damage the building blocks of DNA's double helix structure, which can lead to cell death unless the damage is repaired.

Because cancer cells multiply rapidly, they take in a high concentration of alkylating agents, and their DNA is frequently exposed and rarely repaired. So they die off more often than most other cells, which have time to fix damaged DNA and don't accumulate the same concentrations of alkylating agents.

Another form of chemotherapy involves compounds called microtubule stabilizers. Cells have small tubes that assemble to help with cell division and DNA replication, then break back down.

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