A new study published in the journal ACS Nano shows how nanoparticles might be used to fight lung cancer. The authors describe how they developed nanocarriers that can release chemotherapy drugs selectively at tumor sites without affecting tumor-free areas.

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Using nanocarriers increased the anticancer drug's effectiveness in tumor tissue by 10 to 25 times.
Image credit: Sabine van Rijt, CPC/iLBD, HMGU

The study is a project between scientists from two centers in Munich, Germany - the Helmholtz Zentrum München (HMGU) and the Ludwig-Maximilians-Universität (LMU) - and shows how the nanocarrier approach was able to deliver current cancer medicines for treating lung tumors more effectively than conventional methods.

According to the World Health Organization, lung cancer is the leading cause of cancer death worldwide - accounting for 1.59 million deaths in 2012.

Where cancer starts in the lung, it falls into one of two groups: small cell lung cancer or nonsmall cell lung cancer.

Treatment of lung cancer depends on how big the cancer is and whether it has spread. Treatment options include surgery, chemotherapy, radiotherapy, or a combination of these.

Chemotherapy is mainly used to treat small cell lung cancer, although it is sometimes also used to treat nonsmall cell lung cancer.

Nanoparticles are very small particles whose dimensions are on a par with atoms and molecules. At this scale, matter can be manipulated in ways not seen before. Nanotechnology is emerging as an exciting field with potential applications in medicine.

In this study, the scientists designed nanoparticles that react in a certain way when they enter a lung tumor. Tumor tissue in the lung has high levels of enzymes called proteases that digest particular proteins.

Nanoparticles lose shell only inside tumors - where protease levels are high

The team gave the nanoparticles a protective shell that resists attack from the proteases when they encounter them at the weak concentrations inside healthy tissue.

But when the nanoparticles enter a tumor, the higher concentration of proteases breaks down the shell. Such a feature makes the nanoparticles ideal carriers of drugs that could be released precisely inside tumors.

The team carried out a range of experiments to see how well the nanocarriers can ferry and release drugs selectively into lung tumors.

They ran experiments using lung cancer cells, using 3D tissue cultures of lung cancer, using mice with lung cancer, and using healthy mice to see how well the nanocarriers performed while carrying the chemotherapy drug cisplatin.

Cisplatin is a widely used chemotherapy drug that also affects healthy tissue. But the scientists were able to show that the nanocarrier only released the cisplatin in tumors. When in tumor-free areas, the cisplatin remained inside the nanocarrier, and was not released.

Nanocarrier increased effectiveness of cisplatin in tumor tissue by up to 25 times

Senior author Silke Meiners, of the Comprehensive Pneumology Center at HMGU and LMU, says:

"We observed that the drug's effectiveness in the tumor tissue was 10 to 25 times greater compared to when the drugs were used on their own."

She explains that the nanocarrier method would allow the use of much lower doses of anticancer drugs, which in turn would also reduce undesirable side effects.

The team is now planning to carry out further studies on the safety and effectiveness of nanocarriers in live mice with lung cancer.

In January 2015, Medical News Today reported how another group of scientists is also working on a selective drug delivery system that uses nanotechnology. Their method - which they call "triggered release" - uses two "parent" nanoparticles, each carrying one half of the drug, that come together in the target cell to release their "daughter" cargo.