There is a phrase that gets tossed around every now and then: “For every two steps forward one step back.” This saying couldn’t be farther from the truth in the world we live in today. Over the years, we have done much in the way of technology in order to make our living conditions better. As a result of these endeavors, our average life expectancy has increased, although how much varies by economic status. However, with these improvements to our health and quality of life, we are also see illnesses that, due to our short lives, did not have a chance to manifest very often. Among them is cancer. Today, cancer is a hot topic for researchers around the world as more and more people become diagnosed with cancer. Because of its widespread appearance and its inevitable result—death, it is imperative that we must find a way to treat it. However, nothing is ever so simple. Currently, treatments that are being used include the infamous, chemotherapy. Chemotherapy is a “brute-force” method that, as a side-effect, also kills healthy, non-cancerous cell. It is highly toxic to every type of cell in the human body. In the normal human body, the immune system can detect, or recognize, antigens that appear only on the surface of tumor cells; they will “take care” of such cells accordingly — kill them. One might ask that if this is true, then why is cancer such a big problem? In most cases, cancer devolves later in life. This is because of all of the stress we place on our bodies in our everyday activities. The immune system becomes unable to keep up with the naturally occurring cancer cells in our bodies. This continues until the immune system stops detecting these cells and they grow into masses called tumors. However, there are cases where young people can also develop cancers. This is often due to them being predisposed to cancer both environmentally and genetically. One approach to solving the cancer question is to look at the cancer itself and treating it directly. A different way is to work on the immune system of a patient. The reason why the immune system stops reacting to cancer cells is partly due to the fact that the patient’s immune system is so compromised that there aren’t enough specialized T cells to combat the cancer cells. Moreover, T cells are consumed when they kill target cells. If we are able to stimulate the continuous production of correct T cells, we might be able to enhance a person’s immune system to attack the tumors. Sean Marrache, Smanla Tundup, Donald A Harn, and Shanta Dhar are researchers who view cancer form this angle, by trying to test whether or not a cancer patient’s immune system can be boosted for eliminating cancer cells.
In search of a safer alternative to the current solution, chemotherapy, Marrache et al. decided to use a method called photodynamic therapy (PDT). This method uses a light activated photosensitizer (PS) to kill cancer cells. However, photosensitizers, such as zinc phthalocyanine (ZnPc), have limitations of their own. PSs are hydrophobic which means that they have poor solubility in water, and they might become stuck in the also hydrophobic cell membranes. This makes it difficult to deliver such drug molecules to their intended targets. In order to solve this issue, Marrache and his co-workers hypothesize that they can use a hydrophilic polymer, poly(lactide-co-glycolide)-b-polyethyleneglycol (PLGA-b-PEG), to make a nanoparticle (NP) to contain the PSs and facilitate the delivery of the PS. In addition to being hydrophilic, the NPs are also positively charged which allows them to pass through the negatively charged mitochondria membrane.
Besides trying to deliver PS drugs into cancer cells more efficiently, these researchers also made an educated guess that they could take this method further by targeting mitochondria of cancer cells and inducing apoptosis, the process of programmed cell death. Dendritic cells (DCs), antigen presenting cells, would then pick up antigens
