Conclusion and prospect
Lipid adjuvants have made remarkable achievements in the treatment of
cancer, and their good
immunogenicity, safety and
controllability have been proved. In this review, we summarized two
roles in adjuvants of lipids: delivery carrier and immune stimulants.
According to the new understanding of current immune cell biology, we
can create new lipids with immunogenicity, or carry out structural
modification based on the preexisting lipids to obtain more optimized
products, to further reduce the clinical dosage of drugs and improve the
compliance of cancer patients.
Furthermore, due to the complexity of the human environment, especially
the variability of the tumor environment, it is not only need to
consider the internal association between the carriers and antigens, but
also the influence of the biological characteristics in vivo[93]. A new platform must be developed to respond to the structure
and biological characteristics of the target cells to overcome the
complex mechanism of immunosuppression in tumor microenvironments. Based
on the key parameters such as surface charge, membrane fluidity, andin vivo transfection rate, new lipid materials or functionalized
liposomes will be added to establish a new liposome delivery platform.
Using this platform to deliver antigens and immune stimulants and
promote the cross presentation of antigens is a development direction of
cancer vaccines in the future.
Whereas, the safety and stability of new materials are the keys to the
successful establishment of the delivery platform [7]. Liposome
cancer vaccine has no long-term safety record and needs to be further
verified. The cancer vaccine containing lipid adjuvant is amazing in
clinical trials, the existing experimental data were only for individual
types of tumors, and there is still a lack of extensive and
comprehensive clinical trial data, which indicates that it is still a
long way to go from laboratory to clinical application. At the same
time, the induction data of this new adjuvant in vivo andin vitro were not consistent, so an efficient and simple method
should be established to visualize the immune response, that is, to
monitor the changes of the number, function, and immune behavior of
immune cells in vivo [94]. Only by solving all the above
problems, the application of lipid adjuvants in cancer vaccines can
support the future demand.