leading to safer treatment and better outcomes, according to a recent review.
Nanomedicines homing in on the Wnt/beta-catenin signaling pathway could be particularly impactful, Mamatha Bhat, MD, PhD, a hepatologist and clinician-scientist at Toronto General Hospital Research Institute, and colleagues reported, as this is one of the most up-regulated pathways in HCC.
To date, however, agents addressing this pathway have been hindered by off-target toxicity, suggesting that more work is needed to develop the right payload for nanoparticle delivery, the investigators wrote in Gastro Hep Advances.
“Although nanotherapeutics offers an unmatched improvement in drug delivery, due to the limited impact and treatment-resistance demonstrated by the current systemic therapies, there is currently no approved nanomedicine for the treatment of HCC,” the investigators wrote. “Therefore, it is of utmost importance to dig deeper into understanding the signaling pathways that govern hepatocarcinogenesis and identify novel targets that can be used to develop more specific and targeted nanotherapies.”
Their review focused on the Wnt/beta-catenin signaling pathway, but first, Dr. Bhat and colleagues discussed the characteristics of inorganic versus lipid nanoparticles, as these differences can determine liver uptake.
Inorganic nanoparticles have a high surface-to-volume ratio, leading to increased surface charges that enhance cellular uptake. However, they are prone to oxidation, requiring surface modifications or short circulation times to prevent degradation. These nanoparticles are limited in delivering chemotherapeutic drugs and peptides, and are not suitable for encapsulating nucleic acids.
In contrast, lipid nanoparticles are preferred for targeted delivery in HCC, according to the investigators. They have a natural affinity for apolipoprotein E (apo E), resembling lipoproteins, which aids in specific liver cell targeting. When lipid nanoparticles enter the bloodstream, they interact with apo E–rich lipoproteins like HDL cholesterol and LDL cholesterol, leading to formation of complexes recognized by LDL cholesterol receptors on liver cells. This triggers receptor-mediated endocytosis, internalizing apo E–lipid nanoparticle complexes into HCC cells.
The other major variable is the selected treatment target. Dr. Bhat and colleagues made the case for the Wnt/beta-catenin signaling pathway based on alterations found in approximately two-thirds of patients with HCC.
“Aberrant activation of this pathway and mutations in genes encoding key components are characteristic to hepatocarcinogenesis and promote tumor growth and dedifferentiation,” they wrote.
Although beta-catenin itself makes for an obvious molecular target, especially considering known associations with drug resistance, its flat structure lacks deep binding pockets that would be suitable for small-molecule inhibitors, and any available pockets may be altered by numerous posttranscriptional modifications. Instead, beta-catenin could be indirectly modulated by nanoparticle-mediated siRNA therapy, as this would allow for precise delivery of siRNA to cancer cells, minimizing off-target toxicity.
Alternative approaches could involve targeting proteasomal degradation of beta-catenin, transcriptional coactivators of beta-catenin, or different oncogenes in HCC, all of which are described in further detail in the review, along with promising preclinical findings.
“With ongoing advancements in nanotechnology, there is optimism that it will continue to play a vital role in overcoming the challenges associated with HCC management and contribute to further advancements in therapeutic outcomes for patients,” the authors concluded.
One coauthor disclosed external funding by a Mitacs Elevate postdoctoral fellowship in collaboration with Highland Therapeutics. The remaining authors disclosed no conflicts of interest.
