Cancer treatment has come a long way, but many therapies still struggle with targeting tumor cells without damaging healthy tissues. A promising approach gaining attention involves using vitamin B2 (also called riboflavin) to deliver drugs to cancer cells with higher specificity.
What is Vitamin B2?
Vitamin B2, is a water-soluble vitamin essential for various cellular processes. In fact, its derivatives play a crucial role in energy production, cellular function, and metabolism. Humans must obtain vitamin B2 from food, mostly organs, cereals, or green leaf vegetables.
In humans, riboflavin enters cells via specific transporters: RFVT 1, 2, and 3. Interestingly, research has shown that these transporters are overexpressed in many types of tumors, as cancer cells have a higher energy expenditure compared to normal cells and, therefore, require more vitamin B2 derivatives. The higher concentration of these transporters on these cells could be exploited for targeted drug delivery.
How Riboflavin-Targeted Drug Delivery Works
By attaching riboflavin to drug molecules or carriers, scientists can create a “guided missile” system. This system directs the therapeutic agents to cancer cells that overexpress riboflavin transporters, enhancing the delivery of drugs precisely where they are needed. Several types of riboflavin-conjugated drug delivery systems have been explored:
- Ultrasmall Superparamagnetic Iron Oxide Nanoparticles (USPIO):
These nanoparticles, when linked to the vitamin B2 derivatives FMN and FAD, preferentially accumulate in tumor cells due to their high riboflavin transporter levels. FMN-USPIO in particular appears to be a promising diagnostic tool.
- Dendrimers:
These tree-like, highly branched polymers can carry multiple drug molecules. When functionalized with vitamin B2, dendrimers can target cancer cells more effectively. Conjugation with an anti-cancer drug could decrease overall side-effects while simultaneously allowing for higher drug concentrations at the tumor site.
- Liposomes:
Liposomes are vesicles that can encapsulate a large amount of small molecules, including drugs. Vitamin B2-coated liposomes target cancer cells, ensuring that the encapsulated drugs are released specifically in the tumor microenvironment.
- Polyethylene Glycol (PEG) Polymers:
Polymers other than dendrimers have been proven efficient in targeting tumour cells. For example, a PHPMA-vitamin B2 conjugates demonstrated an efficient targeting of breast cancer cells. Further conjugation common anti-cancer drugs allowed specific cancel cell targeting, while maintaining a good therapeutic efficacy.
The overexpression of riboflavin transporters in tumors provides a unique opportunity to maintain the efficacy of cancer treatments while mitigating their toxicity, therefore improving their therapeutic index. By using vitamin B2 as a targeting mechanism, therapies can become more accurate, reducing damage to healthy tissues and minimizing side effects. Preclinical studies have shown promising results, and ongoing research aims to translate these findings into effective clinical treatments.
In summary, riboflavin-targeted drug delivery represents a significant advancement in the fight against cancer. By harnessing the unique properties of vitamin B2 and its transporters, scientists are developing innovative treatments that could offer better outcomes for patients with various types of cancer. For more detailed information, you can refer to the original study on these promising approaches to cancer treatment here.
By Omar Ben Mariem, Department of Pharmacological and Biomolecular Sciences, University of Milan
Source: doi: 10.3390/cancers12020295.