ABSTRACT
Ossification of the spinal ligaments (OSL) is characterized by the appearance of pathologic bone tissue within the spinal ligamentous tissue. OSL tends to occur in the cervical and thoracic segments with important cause of spinal stenosis. Compression of the spinal cord or nerve roots by ossified masses can lead to severe neurological dysfunction, which has a tremendous impact on the quality of life of patients. However, the exact etiology and pathogenesis of OSL are still unclear. Epigenetic regulation is widespread in organisms and refers to the appearance of heritable changes in gene expression without alteration in genomic DNA sequence. As an important form of biodiversity regulation, epigenetic regulation plays an important role in development of several diseases. Epigenetic regulation has multiple manifestations in OSL, including DNA methylation, histone modifications, and non-coding RNA regulation. Sequencing tools, such as gene microarrays, have revealed significant differences in DNA methylation profiles and non-coding RNA expression between ossified and normal spinal ligaments. These differences can cause abnormal expression of osteogenesis-related target genes through direct or indirect pathways, thus affecting the ossification process of spinal ligaments. In addition, interactions between these epigenetic regulatory mechanisms constitute a large and complex regulatory network. Consequently, an in-depth understanding of the role of different epigenetic regulatory mechanisms and the linkages between them in the initiation and progression stages of OSL is expected to provide a valuable reference for the clinical diagnosis and treatment of OSL-related diseases.
ABSTRACT
[This corrects the article DOI: 10.1016/j.apsb.2019.03.006.].
ABSTRACT
Although high-efficiency targeted delivery is investigated for years, the efficiency of tumor targeting seems still a hard core to smash. To overcome this problem, we design a three-step delivery strategy based on streptavidin-biotin interaction with the help of c(RGDfK), magnetic fields and lasers. The ultrasmall superparamagnetic iron oxide nanoparticles (USIONPs) modified with c(RGDfK) and biotin are delivered at step 1, followed by streptavidin and the doxorubicin (Dox) loaded nanosystems conjugated with biotin at steps 2 and 3, respectively. The delivery systems were proved to be efficient on A549 cells. The co-localization of signal for each step revealed the targeting mechanism. The external magnetic field could further amplify the endocytosis of USPIONs based on c(RGDfK), and magnify the uptake distinctions among different test groups. Based on photoacoustic imaging, laser-heating treatment could enhance the permeability of tumor venous blood vessels and change the insufficient blood flow in cancer. Then, it was noticed that only three-step delivery with laser-heating and magnetic fields realized the highest tumor distribution of nanosystem. Finally, the magnetism/laser-auxiliary cascaded delivery exhibited the best antitumor efficacy. Generally, this study demonstrated the necessity of combining physical, biological and chemical means of targeting.
ABSTRACT
Recently, considerable attention in the field of cancer therapy has been focused on the mammalian rapamycin target (mTOR), inhibition of which could result in autophagic cell death (ACD). Though novel combination chemotherapy of autophagy inducers with chemotherapeutic agents is extensively investigated, nanomedicine-based combination therapy for ACD remains in infancy. In attempt to actively trigger ACD for synergistic chemotherapy, here we incorporated autophagy inducer rapamycin (RAP) into 7pep-modified PEG-DSPE polymer micelles (7pep-M-RAP) to specifically target and efficiently priming ACD of MCF-7 human breast cancer cells with high expression of transferrin receptor (TfR). Cytotoxic paclitaxel (PTX)-loaded micelle (7pep-M-PTX) was regarded as chemotherapeutic drug model. We discovered that with superior intracellular uptake and more tumor accumulation of micelles , 7pep-M-RAP exhibited excellent autophagy induction and synergistic antitumor efficacy with 7pep-M-PTX. Mechanism study further revealed that 7pep-M-RAP and 7pep-M-PTX used in combination provided enhanced efficacy through induction of both apoptosis- and mitochondria-associated autophagic cell death. Together, our findings suggested that the targeted excess autophagy may provide a rational strategy to improve therapeutic outcome of breast cancer, and simultaneous induction of ACD and apoptosis may be a promising anticancer modality.