mice survived, whereas the control and MitP-MNP-treated mice died after 6 days of
tumor cell infection. Furthermore, the histopathological observation revealed that the
supramolecular assemblies had no obvious toxicity to the reticuloendothelial system
(RES) organs, including the liver, spleen, and kidney, implying good biocompatibility of the assemblies. Together, the biocompatible MitP-MNP&HACD could
efficiently suppress tumor invasion and metastasis, preventing death of the mice
from malignant tumors.
The constructed two-dimensional supramolecular assemblies, MNP@GOMitP&HACD (Fig. 4), also have a great impact on tumor metastasis. Besides the
strong efficiency of the assemblies to target and damage the tumor mitochondria,
MNP@GO-MitP&HACD caused severe attenuation of tumor cell (A549-Luc2-tdT-2)
invasion into the Matrigel. Interestingly, no nanostructures were found inside the
invading cells after treatment with MNP@GO-MitP&HACD, indicating that the
Matrigel as confined environment may have hindered internalization of MNP@GOMitP&HACD and that the extracellular 2D nanostructures may have served as a
barrier to cell migration. In vivo metastasis experiments further showed that
MNP@GO-MitP&HACD were distributed at the tumor cell sites and strongly
inhibited migration of the A549-Luc2-tdT-2 tumor cells, restricting the cells to locations near the site at which they had been injected. In contrast, MNP@GO-MitP were
distributed throughout the body and failed to inhibit tumor metastasis; tumor cells
migrated all the way from the injection site to the whole body. This inhibitory effect of
MNP@GO-MitP&HACD on tumor metastasis was further confirmed by the 4T1 lung
metastasis model, in which MNP@GO-MitP&HACD could almost thoroughly prevent lung metastasis of 4T1. These results suggest that the biocompatible MNP@GOMitP&HACD nanostructures could efficiently inhibit tumor invasion and metastasis.
When combined with gold nanorods or chemotherapeutic drugs, this nano-system
could realize both tumor metastasis inhibition and tumor damage simultaneously.
For example, in one of our other study, a strategy of metastasis prevention-photothermal removal cooperation was developed for enhancement of the anticancer
efficiency (Fig. 6) [34]. The growth of the AuNR-MitP-MNP&HACD nanofibers,
which are composed by HACD and MitP-modified gold nanorods (AuNR-MitPMNPs), was precisely regulated by the weak geomagnetic field. In the biological
systems, the nanofibers could suppress tumor cell metastasis by restricting the cells
to a confined environment. When the tumor site was irradiated by a near-infrared
(NIR) laser, the tumor tissues were severely damaged and removed. Therefore, the
developed magnetic supramolecular assemblies have a bright application prospect in
tumor therapy and related treatment.
20.4.4 MRI
MRI is an emerging and powerful imaging strategy, since that it exhibits excellent
spatial resolution of soft tissues, low toxicity to normal cells, and deep tissue
penetration. Although MRI had relatively low sensitivity as compared to optical
imaging and positron emission tomography, its sensitivity could be enhanced with
20 Construction and Biomedical Application of Magnetic Supramolecular. . .
567
tumor cell infection. Furthermore, the histopathological observation revealed that the
supramolecular assemblies had no obvious toxicity to the reticuloendothelial system
(RES) organs, including the liver, spleen, and kidney, implying good biocompatibility of the assemblies. Together, the biocompatible MitP-MNP&HACD could
efficiently suppress tumor invasion and metastasis, preventing death of the mice
from malignant tumors.
The constructed two-dimensional supramolecular assemblies, MNP@GOMitP&HACD (Fig. 4), also have a great impact on tumor metastasis. Besides the
strong efficiency of the assemblies to target and damage the tumor mitochondria,
MNP@GO-MitP&HACD caused severe attenuation of tumor cell (A549-Luc2-tdT-2)
invasion into the Matrigel. Interestingly, no nanostructures were found inside the
invading cells after treatment with MNP@GO-MitP&HACD, indicating that the
Matrigel as confined environment may have hindered internalization of MNP@GOMitP&HACD and that the extracellular 2D nanostructures may have served as a
barrier to cell migration. In vivo metastasis experiments further showed that
MNP@GO-MitP&HACD were distributed at the tumor cell sites and strongly
inhibited migration of the A549-Luc2-tdT-2 tumor cells, restricting the cells to locations near the site at which they had been injected. In contrast, MNP@GO-MitP were
distributed throughout the body and failed to inhibit tumor metastasis; tumor cells
migrated all the way from the injection site to the whole body. This inhibitory effect of
MNP@GO-MitP&HACD on tumor metastasis was further confirmed by the 4T1 lung
metastasis model, in which MNP@GO-MitP&HACD could almost thoroughly prevent lung metastasis of 4T1. These results suggest that the biocompatible MNP@GOMitP&HACD nanostructures could efficiently inhibit tumor invasion and metastasis.
When combined with gold nanorods or chemotherapeutic drugs, this nano-system
could realize both tumor metastasis inhibition and tumor damage simultaneously.
For example, in one of our other study, a strategy of metastasis prevention-photothermal removal cooperation was developed for enhancement of the anticancer
efficiency (Fig. 6) [34]. The growth of the AuNR-MitP-MNP&HACD nanofibers,
which are composed by HACD and MitP-modified gold nanorods (AuNR-MitPMNPs), was precisely regulated by the weak geomagnetic field. In the biological
systems, the nanofibers could suppress tumor cell metastasis by restricting the cells
to a confined environment. When the tumor site was irradiated by a near-infrared
(NIR) laser, the tumor tissues were severely damaged and removed. Therefore, the
developed magnetic supramolecular assemblies have a bright application prospect in
tumor therapy and related treatment.
20.4.4 MRI
MRI is an emerging and powerful imaging strategy, since that it exhibits excellent
spatial resolution of soft tissues, low toxicity to normal cells, and deep tissue
penetration. Although MRI had relatively low sensitivity as compared to optical
imaging and positron emission tomography, its sensitivity could be enhanced with
20 Construction and Biomedical Application of Magnetic Supramolecular. . .
567