Q1. What is the difference between a cold tumor and a hot tumor?
“Cold tumor” and “Hot tumor” are terms that indicate the immune response status of a tumor. In the case of most solid cancers, they refer to the state of a tumor being “Cold” or “Hot” in terms of immune recognition and infiltration. A “Cold tumor” is one where immune cells, particularly T cells, fail to infiltrate the tumor effectively, leading to a lack of immune activation. This makes it difficult to achieve therapeutic effects with immune checkpoint inhibitors, which aim to activate the immune response against the tumor. Conversely, a “Hot tumor” signifies a tumor in which immune cells successfully infiltrate, leading to an activated immune response within the tumor microenvironment.
Hot tumors tend to exhibit higher response rates to immune checkpoint inhibitors, making the conversion from a Cold tumor to a Hot tumor a key aspect of cancer treatment.
Q2. Why is it difficult to treat solid cancer?
To treat solid tumors, two barriers need to be overcome: physical and immune barriers.
In the case of solid tumors, cancer cells manipulate the tumor microenvironment and surrounding fibrous tissue to their advantage, promoting their growth. The area around cancer cells becomes enriched with extracellular matrix (ECM), creating a physically challenging environment that hinders penetration of external cells and drugs. Even if immune cells (T cells) manage to infiltrate, the closed microenvironment within solid tumors, characterized by low pH, insufficient nutrients, and oxygen, makes activating immune responses difficult. Furthermore, due to the influence of surrounding cells, an immune-suppressive environment is formed around solid tumors, making it hard for T cells to activate from the outside. Overcoming these limitations requires the development of third-generation immunotherapies that can surmount these obstacles.
Q3. What is the reason for using exosomes as a delivery tool?
Exosomes are extracellular vesicles derived from cells, enclosed in a lipid bilayer structure similar to cells, making them stable. They contain proteins, enzymes, various nucleic acids, and other substances from their originating cells. To date, research indicates that they are secreted as a response to intercellular communication or external stimuli. These characteristics make exosomes optimized for drug delivery. Their stable lipid membrane structure ensures stability within the body, they are non-immunogenic, and their versatility allows for various engineering approaches, including targeted drug delivery to specific cells.
Q4. What is an immunotherapy for cancer?
Immunotherapy for cancer refers to a treatment that activates the suppressed immune system to exhibit an anticancer effect. Cancer cells manipulate the surrounding environment and cells to inhibit immune responses against them, evading attacks from immune cells. Immunotherapy works by reactivating suppressed immune cells and enabling them to target and attack cancer cells once again. Notable immunotherapies include Keytruda, Tecentriq, and Kymriah. However, currently available immunotherapies have shown limitations in treating solid tumors, and there’s a growing need for next-generation immunotherapies to overcome these constraints for effective solid tumor treatments.
Q5. What is CMC?
CMC stands for Chemistry, Manufacturing, and Control, encompassing all processes related to process development, quality management, and production from clinical samples to commercial pharmaceutical products. Even if a drug possesses therapeutic potential, it must meet specified standards and be consistently produced as a pharmaceutical product of uniform quality to successfully pass through clinical and regulatory phases and be distributed in the market.
To achieve this, the manufacturing process involves designing experimentally verified manufacturing methods that assure quality, determining the structure of Active Pharmaceutical Ingredients (APIs), establishing validated analytical methods, confirming impurities, and conducting stability tests. CMC is a critical domain that undertakes these steps to guarantee the quality and consistency of pharmaceutical products, making it an essential process for the commercialization of drugs.
Q6. What is the most commonly used method for exosome purification?
The most commonly used methods for exosome purification include ultracentrifugation, density gradient centrifugation, tangential flow filtration, ion exchange chromatography, polymer-based precipitation, immunoaffinity isolation, and exosome purification kits. In the exosome industry, ultracentrifugation, tangential flow filtration, and ion exchange chromatography are generally the most common methods for exosome purification.
