Progress of nanoparticles inhibiting tumor metastasis

Tumor metastasis has become one of the great challenges of cancer diagnosis and effective treatment. Metastasis, a process is depicted that the primary tumor spread to distant organs or tissues to compose the new “citadel”. The circulating tumor cells which are escaping the immune surveillance can transfer to the host tumor and tissue. Once these adapt to the “host organ” microenvironment, composing the “metastatic tumor” with a strong multi-drug resistance. Therefore, curing the metastatic tumor hardly uses the traditional treatment independently. Nowadays, we focus on how to use the functional nanoparticles (NPs)to inhibit tumor metastasis effectively. One of treating metastasis issues is enriching the NPs in the tumor tissue. The EPR effect is the “navigator” of NPs. They can reach the tumor site effectively and tracing or inhibiting the metastatic tumor in possibility. Some research have found that the permeability factor such as nitric oxide contributed to the role of EPR effect in the tumor site, it improved the vascular permeability of the tumor site selectively, proved that NPs can be effectively delivered to the tumor site. Tumor tissues often show the specificity, which make the NPs target to the specific tumor tissue modifying the specific antibody. The NPs can be encapsulated by the homologous cancer cell membrane and release the anti-tumor drugs in the vicinity effectively, improving the treatment efficiency and the therapeutic effect obviously.. Nowadays, the CRISPR immune system develop a new gene editing technique. To delivery Cas-9 system in high efficiency, we can design a series of functional-nanoparticle delivery system. It is a kind of method which is safer than the virus vector and much more efficiency than the plasmid. In the meanwhile, it can grasp the relationship between the lack of gene function and phenotype of metastasis with controlling the tumor growth. Inhibition of CTCs in vivo circulation is the most indispensable step in preventing tumor metastasis, but it is hardly to capture circulating CTCs in the background of hundreds of millions of cells in the circulatory system effectively. In view of this problem, the researchers make use of NPs which can be modified. They can targeting and enriching the CTCs to inhibit the metastasis. We can predict that using NPs to develop microchips can capture and enrich CTCs in the blood circulation efficiently. Tumor “relapse” has been a clinical cure for cancer problem, especially malignant glioma which forms in the brain. Due to its good tumor tissue infiltration, it is hardly to remove the tumor completely by making surgery merely, and account for the secondary metastatic easily. Depending on the good targeting to tumor tissue, the magnetic nanoparticles(MNPs) can inhibit the expression of epidermal growth factor (EGFR) within the loaded-antibody. Moreover, they combine it with magnetic resonance imaging, locating the tumor accurately. It is improved that the MNPs inhibit the expression of EGFR and tumor recurrence and secondary metastasis potentially, indicating that the NPs have a great value with a long-distanced applying in clinic. In all, the review pays attention to the two aspects of metastases, including the inhibition of primary tumor invasion or metastasis and metastases proliferation or recurrence. Meanwhile, prospecting that the NPs can make great contributes to change the clinical treatment in the predicted future.