Selenium-doped calcium phosphate biomineral reverses multidrug resistance to enhance bone tumor chemotherapy

Calcium Phosphate-Based Nanomaterials: Preparation, Multifunction, and Application for Bone Tissue Engineering

Calcium phosphate is the main inorganic component of bone. Calcium phosphate-based biomaterials have demonstrated great potential in bone tissue engineering due to their superior biocompatibility, pH-responsive degradability, excellent osteoinductivity, and similar components to bone. Calcium phosphate nanomaterials have gained more and more attention for their enhanced bioactivity and better integration with host tissues. Additionally, they can also be easily functionalized with metal ions, bioactive molecules/proteins, as well as therapeutic drugs; thus, calcium phosphate-based biomaterials have been widely used in many other fields, such as drug delivery, cancer therapy, and as nanoprobes in bioimaging. Thus, the preparation methods of calcium phosphate nanomaterials were systematically reviewed, and the multifunction strategies of calcium phosphate-based biomaterials have also been comprehensively summarized. Finally, the applications and perspectives of functionalized calcium phosphate biomaterials in bone tissue engineering, including bone defect repair, bone regeneration, and drug delivery, were illustrated and discussed by presenting typical examples.

Enzyme-catalyzed synthesis of selenium-doped manganese phosphate for synergistic therapy of drug-resistant colorectal cancer

BACKGROUND

The development of multidrug resistance (MDR) during postoperative chemotherapy for colorectal cancer substantially reduces therapeutic efficacy. Nanostructured drug delivery systems (NDDSs) with modifiable chemical properties are considered promising candidates as therapies for reversing MDR in colorectal cancer cells. Selenium-doped manganese phosphate (Se-MnP) nanoparticles (NPs) that can reverse drug resistance through sustained release of selenium have the potential to improve the chemotherapy effect of colorectal cancer.

RESULTS

Se-MnP NPs had an organic-inorganic hybrid composition and were assembled from smaller-scale nanoclusters. Se-MnP NPs induced excessive ROS production via Se-mediated activation of the STAT3/JNK pathway and a Fenton-like reaction due to the presence of manganese ions (Mn²⁺). Moreover, in vitro and in vivo studies demonstrated Se-MnP NPs were effective drug carriers of oxaliplatin (OX) and reversed multidrug resistance and induced caspase-mediated apoptosis in colorectal cancer cells. OX@Se-MnP NPs reversed MDR in colorectal cancer by down-regulating the expression of MDR-related ABC (ATP binding cassette) transporters proteins (e.g., ABCB1, ABCC1 and ABCG2). Finally, in vivo studies demonstrated that OX-loaded Se-MnP NPs significantly inhibited proliferation of OX-resistant HCT116 (HCT116/DR) tumor cells in nude mice.

CONCLUSIONS

OX@Se-MnP NPs with simple preparation and biomimetic chemical properties represent promising candidates for the treatment of colorectal cancer with MDR.

Multifunctional inorganic biomaterials: New weapons targeting osteosarcoma

Osteosarcoma is the malignant tumor with the highest incidence rate among primary bone tumors and with a high mortality rate. The anti-osteosarcoma materials are the cross field between material science and medicine, having a wide range of application prospects. Among them, biological materials, such as compounds from black phosphorous, magnesium, zinc, copper, silver, etc., becoming highly valued in the biological materials field as well as in orthopedics due to their good biocompatibility, similar mechanical properties with biological bones, good biodegradation effect, and active antibacterial and anti-tumor effects. This article gives a comprehensive review of the research progress of anti-osteosarcoma biomaterials.

Loading and Releasing Behavior of Selenium and Doxorubicin Hydrochloride in Hydroxyapatite with Different Morphologies

Doxorubicin (Dox)-loaded or selenium-substituted hydroxyapatite (HA) has been developed to achieve anti-osteosarcoma or bone regeneration in a number of studies. However, currently, there is a lack of studies on the combination of Dox and selenium loading in/on HA and comparative research studies on which form and size of HA are more suitable for drug loading and release in the treatment osteogenesis after osteosarcoma resection. Herein, selenium-doped rod-shaped nano-HA (n-HA) and spherical mesoporous HA (m-HA) were successfully prepared. The doping efficiency of selenium and the Dox loading capacity of selenium-doped HA with different morphologies were studied. The release kinetics of Dox and the selenium element in phosphate-buffered saline with different pH values was also comparatively investigated. The drug loading results showed that n-HA exhibited 3 times higher selenium doping amount than m-HA, and the Dox entrapment efficiency of selenium-doped n-HA (0.1Se-n-HA) presented 20% higher than that of selenium-doped m-HA (0.1Se-m-HA). The Dox release behaviors of HA in two different morphologies showed similar release kinetics, with almost the same Dox releasing ratio but slightly more Dox releasing amount in selenium-doped HA than in HA without selenium. The selenium release from selenium-doped n-HA-D (0.1Se-n-HA-D) particles was 2 times as much as that of selenium-doped m-HA-D (0.1Se-m-HA) particles. Our study indicated that n-HA loaded with Dox and selenium may be a promising drug delivery strategy for inhibition of osteosarcoma recurrence and promoting osteogenesis simultaneously.