According to the British Journal of Cancer, 1 in 2 people will be diagnosed with cancer at some point in their lives. Worldwide, cancer is a leading cause of death, claiming the lives of around 10 million people in 2020, with lung cancer, followed by colon and rectum cancer, liver cancer, stomach cancer, and breast cancer, causing the most cancer-related deaths in the same year.
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Given that currently, only 30% of cancers are routinely cured, there is a clear and urgent need for more effective therapeutic options, particularly for treatment-resistant cancer. Recent research has demonstrated the vast potential of nanotechnology in the field of oncology.
The rapidly growing scientific discipline has been leveraged in the field of diagnostics, treatment, and prevention of cancer, particularly for early detection and effective drug delivery. Here, we discuss a specific emerging field of research into the use of semiconducting polymer nanomaterials for cancer and tumor treatment.
The Growing Use of Nanotechnology in Cancer Treatment
The concept of nanotechnology was established back in 1959; however, the ‘golden era of nanotechnology’ didn’t truly start until the scanning tunneling microscope was invented in 1981. Over the past four decades, the potential of nanotechnology has been intensely studied and explored in many fields of science. In particular, it has been extensively studied in the realm of cancer treatment.
Nanoparticles, tiny molecules with relatively large surface areas, have unique properties that make them highly useful in drug delivery systems. Nanoparticles have numerous advantages when compared with conventional drugs. For example, they have enhanced biocompatibility and stability, improved permeability and retention effect, and precise targeting.
Current therapeutic options, such as chemotherapy, are being enhanced by nanotechnology. Already, the technology is being used to deliver therapeutic molecules directly and selectively to cancer cells, guide the surgical resection of tumors, and improve the efficacy of radiation-based and other treatment modalities. As a result, nanotechnology is helping to improve the probability of survival and reduce the side effects of treatment.
The relatively large surface area of nanoparticles can be made to work with ligands such as strands of DNA or RNA, peptides, aptamers, and antibodies. Functionalizing nanoparticles with these ligands opens up the opportunity of leveraging them to direct a therapeutic effect. As a result, many therapeutic modalities have been established by combining nanoparticles and ligands, including combination drug delivery, multi-modality treatment, “theranostic” action methods, modalities of disease tissue disruption, laser ablation, and hyperthermia applications.
Below, we focus on using semiconducting polymer nanoparticles in cancer treatment via two specific examples of colorectal cancer and pancreatic cancer.
Using Semiconducting Polymer Nanoparticles to Treat Colorectal Cancer
Treatment of colorectal cancer is limited by micrometastatic relapse that is often resistant to chemotherapy and surgery is unable to completely remove. New research has looked into how targeted theranostic nanoparticles can be used to improve the treatment of this type of cancer.
Already, it has been determined that theranostic nanoparticles can produce heart for ablation and facilitate tumor visualization due to their fluorescence, lending them to applications in the detection and treatment of disseminated small nodules. However, the interaction of nanoparticles with the 3D tumor microenvironment had acted as a major obstacle to the clinical translation of this application.
To overcome this hurdle, scientists used tumor organoid technology to evaluate the ablative potential of specific nanoparticles (CD44-targeted polymer). The team used hyaluronic acid as the targeting agent and applied it as a coating to hybrid donor-acceptor polymer particles. Photothermal polymer nanoparticles were also coated with hyaluronic acid and evaluated.
The results showed that the non-targeted hybrid donor-acceptor polymer particles demonstrated a uniform diffusion compared to the hyaluronic acid-hybrid donor-acceptor polymer particles, which showed attenuated diffusion due to nanoparticle-matrix interactions. The scientists concluded that nanoparticle/cell matrix interactions may have accounted for the diffusion profile of the hyaluronic acid-hybrid donor-acceptor polymer particles.
Overall, the research demonstrated that the theranostic nanoparticles displayed enhanced photothermal ablation in 3D, which could be developed into an assessment protocol for testing nanoparticle therapies before in vivo testing.
Using Semiconducting Polymer Nanoparticles To Treat Pancreatic Tumors
Pancreatic cancer tends to have a poor prognosis due to the low efficacy and high side effects of currently available treatments. In a step towards developing much-needed treatment options, scientists established a combined radio- and photothermal therapy for pancreatic tumors using a semiconducting polymer nano-radiopharmaceutical alongside a therapeutic radioisotope for labeling.
The new approach demonstrated enhanced efficacy at killing cancer cells compared with radiotherapy or photothermal therapy alone. The platform may be developed into a therapeutic capable of reducing metastasis. If developed, such a strategy may significantly impact patient outcomes and quality of life.
The Future for Semiconducting Polymer Nanomaterials in Cancer Treatment
Scientists are currently just scratching the surface of the potential of semiconducting polymer nanomaterials in cancer treatment, but results so far have been promising. Over the coming years, more applications will likely emerge, and more cancer types will be targeted.
References and Further Reading
McCarthy, B., Cudykier, A., Singh, R., Levi-Polyachenko, N. and Soker, S., (2021) Semiconducting polymer nanoparticles for photothermal ablation of colorectal cancer organoids. Scientific Reports, 11(1). Available at: https://www.nature.com/articles/s41598-021-81122-w
Shi, X., Li, Q., Zhang, C., Pei, H., Wang, G., Zhou, H., Fan, L., Yang, K., Jiang, B., Wang, F. and Zhu, R., (2021) Semiconducting polymer nano-radiopharmaceutical for combined radio-photothermal therapy of pancreatic tumor. Journal of Nanobiotechnology, 19(1). Available at https://jnanobiotechnology.biomedcentral.com/articles/10.1186/s12951-021-01083-0
Zhang, Y., Li, M., Gao, X., Chen, Y. and Liu, T., (2019) Nanotechnology in cancer diagnosis: progress, challenges and opportunities. Journal of Hematology & Oncology, 12(1). Available at: https://jhoonline.biomedcentral.com/articles/10.1186/s13045-019-0833-3