Chemical Profiling, Quantitation, and Bioactivities of Ginseng Residue.

Ginseng residue is a by-product stemming from the commercial extraction of ginsenosides. To assess the disparities between ginseng residue and ginseng tablet, we employed the ultra-high-performance liquid chromatography-quadrupole time-of-flight/mass spectrometry (UPLC-Q-TOF/MS) technique for sample analysis. The analyses revealed the presence of 39 compounds in both ginseng residue and ginseng tablets. Subsequently, the contents of total ginsenosides and total ginseng polysaccharides in the ginseng residue and ginseng tablet were determined. The results indicate that while only a small fraction of ginsenosides remained in the ginseng residue, a significant amount of polysaccharides was retained. Furthermore, our evaluation encompassed the antioxidant activities of both ginseng residue and ginseng tablets. Notably, ginseng residue exhibited robust antioxidant effects, thereby showcasing its potential for recycling as a functional food raw material.

Aspect ratio-dependent dual-regulation of the tumor immune microenvironment against osteosarcoma by hydroxyapatite nanoparticles.

Accumulating studies demonstrated that hydroxyapatite nanoparticles (HANPs) showed a selective anti-tumor effect, making them a good candidate for osteosarcoma (OS) treatment. However, the capacity of HANPs with different aspect ratios to regulate tumor immune microenvironment (TIM) was scarcely reported before. To explore it, the three HANPs with aspect ratios from 1.86 to 6.25 were prepared by wet chemical method. After a 24 or 72 h-exposure of OS UMR106 cells or macrophages to the nanoparticles, the tumor cells exhibited immunogenic cell death (ICD) indicated by the increased production of calreticulin (CRT), adenosine triphosphate (ATP) and high mobility group box 1 (HMGB1), and macrophages were activated with the release of pro-inflammatory cytokines. Next, the beneficial crosstalk between tumor cells and macrophages generated in the presence of HANPs for improved anti-tumor immunity activation. In the OS-bearing cognate rat model, HANPs inhibited OS growth, which was positively correlated with CRT and HMGB1 expression, and macrophage polarization in the tumor tissues. Additionally, HANPs promoted CD8+ T cell infiltration into the tumor and systemic dendritic cell maturation. Particularly, HANPs bearing the highest aspect ratio exhibited the strongest immunomodulatory and anti-tumor function. This study suggested the potential of HANPs to be a safe and effective drug-free nanomaterial to control the TIM for OS therapy. STATEMENT OF SIGNIFICANCE: Emerging studies demonstrated that hydroxyapatite nanoparticles (HANPs) inhibited tumor cell proliferation and tumor growth. However, the underlying anti-tumor mechanism still remains unclear, and the capacity of HANPs without any other additive to regulate tumor immune microenvironment (TIM) was scarcely reported before. Herein, we demonstrated that HANPs, in an aspect ratio-dependent manner, showed the potential to delay the growth of osteosarcoma (OS) and to regulate TIM by promoting the invasion of CD8+ T cells and F4/80+ macrophages, and inducing immunogenic cell death (ICD) in tumors. This work revealed the new molecular mechanism for HANPs against OS, and suggested HANPs might be a novel ICD inducer for OS treatment.

Hydroxyapatite nanoparticles promote TLR4 agonist-mediated anti-tumor immunity through synergically enhanced macrophage polarization.

Macrophages represent the most prevalent immune cells in the tumor micro-environment, making them an appealing target for tumor immunotherapy. One of our previous studies showed that hydroxyapatite nanoparticles (HANPs) enhanced Toll-like receptor 4 (TLR4) signal transduction in macrophages. This study was proposed to investigate how HANPs manipulated the phenotype and function of macrophage against 4T1 breast tumors in the presence or absence of MPLA, a low toxic Toll-like receptor 4 (TLR4) agonist. The results demonstrated that the addition of HANPs to MPLA significantly promoted cytokine secretion and macrophage polarization toward a tumoricidal M1 phenotype. Further, the resulting supernatant from HANPs/MPLA co-stimulated macrophages enhanced 4T1 tumor cells apoptosis compared to that from macrophages treated with a single component or PBS control. In particular, we found HANPs elicited immunogenic cell death (ICD) indicated by the increased expression of "danger signals", including HMGB1, CRT and ATP in 4T1 cells. Subsequently, the ICD derivatives-containing supernatant from HANPs-treated 4T1 cells activated macrophage and shifted the phenotype of the cells toward M1 type. Moreover, in a tumor-bearing mice model, HANPs and MPLA synergistically delayed tumor growth compared to PBS control, which was positively associated with the promoted macrophage polarization and ICD induction. Therefore, our findings demonstrated a potential platform to modulate the function of macrophages, and shed a new insight into the mechanism involving the immunomodulatory effect of HANPs for tumor therapy. STATEMENT OF SIGNIFICANCE: Polarizing macrophage toward tumoricidal phenotype by harnessing Toll-like receptor (TLR) agonists has been proven effective for tumor immunotherapy. However, the immunomodulatory potency of TLR agonists is limited due to immune suppression or tolerance associated with TLR activation in immune cells. Herein, we introduced hydroxyapatite nanoparticles (HANPs) to MPLA, a TLR4 agonist. The results demonstrated that the addition of HANPs to MPLA promoted macrophage shift toward tumoricidal M1 phenotype, supported a "hot" tumor transformation, and delayed 4T1 tumor growth. Moreover, we found that HANPs elicited immunogenic cell death that produced "danger" signals from cancer cells thereby further facilitated macrophage polarization. This work is significant to direct the rational design of HANPs coupled with or without TLR agonists for tumor immunotherapy.

A Selective Reduction of Osteosarcoma by Mitochondrial Apoptosis Using Hydroxyapatite Nanoparticles.

Background: In recent years, using hydroxyapatite nanoparticles (HANPs) for tumor therapy attracted increasing attention because HANPs were found to selectively suppress the growth of tumor cells but exhibit ignorable toxicity to normal cells. Purpose: This study aimed to investigate the capacities of HANPs with different morphologies and particle sizes against two kinds of osteosarcoma (OS) cells, human OS 143B cells and rat OS UMR106 cells. Methods: Six kinds of HANPs with different morphologies and particle sizes were prepared by wet chemical method. Then, the antitumor effect of these nanoparticles was characterized by means of in vitro cell experiments and in vivo tumor-bearing mice model. The underlying antitumor mechanism involving mitochondrial apoptosis was also investigated by analysis of intracellular calcium, expression of apoptosis-related genes, reactive oxygen species (ROS), and the endocytosis efficiency of the particles in tumor cells. Results: Both in vitro cell experiments and in vivo mice model evaluation revealed the anti-OS performance of HANPs depended on the concentration, morphology, and particle size of the nanoparticles, as well as the OS cell lines. Among the six HANPs, rod-like HANPs (R-HANPs) showed the best inhibitory activity on 143B cells, while needle-like HANPs (N-HANPs) inhibited the growth of UMR106 cells most efficiently. We further demonstrated that HANPs induced mitochondrial apoptosis by selectively raising intracellular Ca2+ and the gene expression levels of mitochondrial apoptosis-related molecules, and depolarizing mitochondrial membrane potential in tumor cells but not in MC3T3-E1, a mouse pre-osteoblast line. Additionally, the anti-OS activity of HANPs also linked with the endocytosis efficiency of the particles in the tumor cells, and their ability to drive oxidative damage and immunogenic cell death (ICD). Conclusion: The current study provides an effective strategy for OS therapy where the effectiveness was associated with the particle morphology and cell line.

Potential Therapeutic Effects of Short-chain Fatty Acids on Chronic Pain.

The intestinal homeostasis maintained by the gut microbiome and relevant metabolites is essential for health, and its disturbance leads to various intestinal or extraintestinal diseases. Recent studies suggest that gut microbiome-derived metabolites short-chain fatty acids (SCFAs) are involved in different neurological disorders (such as chronic pain). SCFAs are produced by bacterial fermentation of dietary fibers in the gut and contribute to multiple host processes, including gastrointestinal regulation, cardiovascular modulation, and neuroendocrine-immune homeostasis. Although SCFAs have been implicated in the modulation of chronic pain, the detailed mechanisms that underlie such roles of SCFAs remain to be further investigated. In this review, we summarize currently available research data regarding SCFAs as a potential therapeutic target for chronic pain treatment and discuss several possible mechanisms by which SCFAs modulate chronic pain.

Hydroxyapatite nanoparticles drive the potency of Toll-like receptor 9 agonist for amplified innate and adaptive immune response.

The potency of Toll-like receptor 9 (TLR9) agonist to drive innate immune response was limited due to immune suppression or tolerance during TLR9 signaling activation in immune cells. Herein we addressed this problem by introducing hydroxyapatite nanoparticles (HANPs) to CpG ODN (CpG), a TLR9 agonist. The study revealed that HANPs concentration and duration-dependently reprogramed the immune response by enhancing the secretion of immunostimulatory cytokines (tumor necrosis factor α (TNFα) or IL-6) while reducing the production of immunosuppressive cytokine (IL-10) in macrophages in response to CpG. Next, the enhanced immune response benefited from increased intracellular Ca2+ in macrophage by the addition of HANPs. Further, we found exposure to HANPs impacted the mitochondrial function of macrophages in support of the synthesis of adenosine triphosphate (ATP), the production of nicotinamide adenine dinucleotide (NAD), and reactive oxygen species (ROS) in the presence or absence of CpG. In vaccinated mice model, only one vaccination with a mixture of CpG, HANPs, and OVA, a model antigen, allowed the development of a long-lasting balanced humoral immunity in mice without any histopathological change in the local injection site. Therefore, this study revealed that HANPs could modulate the intracellular calcium level, mitochondrial function, and immune response in immune cells, and suggested a potential combination adjuvant of HANPs and TLR9 agonist for vaccine development. Electronic Supplementary Material: Supplementary material (TEM image, LDH activity, the Ca2+ release in PBS, qRT-PCR analysis, H&E staining, and IL-6 level in the injection site and serum) is available in the online version of this article at 10.1007/s12274-022-4683-x.

The Combined Use of Orf Virus and PAK4 Inhibitor Exerts Anti-tumor Effect in Breast Cancer.

The parapoxvirus Orf virus (ORFV) has long been recognized as one of the valuable vectors in researches of oncolytic virus. In order to develop a potential therapeutic strategy for breast cancer based on the oncolytic virotherapy via ORFV, firstly we explore the oncolytic effects of ORFV. Our research showed that ORFV exerts anti-tumor effects in vitro by inducing breast cancer cell G2/M phase arrest and cell apoptosis. In vivo experiments were carried out, in which we treated 4T1 tumor-bearing BALB/C mice via intratumoral injection of ORFV. ORFV can exert anti-tumor activity by regulating tumor microenvironment (TME) and inducing a host immune response plus directly oncolytic effect. The CRISPR-Cas9 knockout library targeting 507 kinases was used to screen out PAK4, which is beneficial to the anti-tumor effect of ORFV on breast cancer cells. PF-3758309 is a potent PAK4-targeted inhibitor. Co-using of ORFV and PF-3758309 as a combination treatment produces its anti-tumor effects through inhibition of cell viability, induction of apoptosis and suppression of cell migration and invasion in vitro. The results of in vivo experiments showed that the tumor growth of mice in the combination treatment group was significantly inhibited, which proved that the combination treatment exerts an effective anti-tumor effect in vivo. In summary, we have clarified the oncolytic effect of ORFV on breast cancer, and found that the combination of ORFV and PAK4 inhibitor can effectively improve the oncolytic effect of ORFV. We hope our research could provide a new idea for the development of new treatment strategies for breast cancer.

Nano-hydroxyapatite-evoked immune response synchronized with controllable immune adjuvant release for strengthening melanoma-specific growth inhibition.

Concerns about the potential systematic toxicity limit the extensive application of traditional therapeutic drugs for melanoma therapy, nano-hydroxyapatite (nHA) with good biocompatibility and anti-tumor ability could be an alternative choice. In this study, nHA was employed as an anti-tumor biomaterial due to its tumor-specific toxicity. Meanwhile, granulocyte-macrophage colony-stimulating factor (GM-CSF) served as the immune adjuvant to activate the immune response. The delivery platform was fabricated by co-encapsulation of both nHA and GM-CSF into a biocompatible thermosensitive PLGA-PEG-PLGA hydrogel. The results showed that the bio-activities of nHA and GM-CSF could be well-maintained within the hydrogel. Interestingly, the addition of nHA could attenuate the burst release of GM-CSF due to possible protein absorption capacity of nHA, which is beneficial for GM-CSF sustainable release at the tumor site, achieving boosted and prolonged anti-tumor immunity. The in vitro and in vivo data demonstrated that nHA/GM-CSF hydrogel exhibited greater potency to inhibit tumor growth via enhanced CD8+ T-cell response compared with hydrogel and nHA hydrogel groups, contributed by the synergistic effects of nHA and GM-CSF. Overall, the strategy combining nHA and immune adjuvant shows great promise, which largely broadens the choice of combinational therapies for melanoma. STATEMENT OF SIGNIFICANCE: Nano-hydroxyapatite (nHA) has been confirmed to specifically inhibit melanoma tumor growth and induce immune response. However, its antitumor efficiency and immunity-evoking capacity are limited. In this study, granulocyte-macrophage colony-stimulating factor (GM-CSF) was introduced to serve as the immune adjuvant. Both of them were encapsulated into a biocompatible thermosensitive PLGA-PEG-PLGA hydrogel. The addition of nHA could attenuate the burst release of GM-CSF due to the interaction with nHA, which is beneficial for GM-CSF sustainable release at tumor site, achieving boosted and prolonged anti-tumor immunity. Anti-tumor immune response could be activated due to the release of tumor-associated antigen and tumor debris induced by the specifically tumor inhibition effect of nHA and GM-CSF. The combination of nHA and GM-CSF could play synergistic inhibiting effect on tumor growth via boosting and prolonging anti-tumor immunity.

Preclinical efficacy and involvement of mTOR signaling in the mechanism of Orf virus against nasopharyngeal carcinoma cells.

AIMS: Orf virus (ORFV) is a parapoxvirus causing contagious ecthyma in sheep and goats. With inhibitory role of ORFV reported by previous studies, ORFV can be a candidate of oncolytic virus. However, few studies reported the application and mechanism of ORFV in nasopharyngeal carcinoma (NPC). We aimed to elucidate the anti-tumor mechanism of ORFV against NPC cells. MATERIALS AND METHODS: The anti-tumor effect of ORFV in NPC cells was confirmed by cell counting kit 8 (CCK-8) assay, flow cytometry and Western blot. In vitro and in vivo experiments were adopted to evaluate the inhibitory effect of ORFV in NPC cells. Western blot was used to determine the down-regulation of rapamycin (mTOR) signaling and autophagy enhancement induced by ORFV. To explore the mechanism of ORFV on NPC cells, mTOR signaling agonist and autophagy inhibitors were used to rescue the effects of ORFV. KEY FINDINGS: The results indicated that ORFV replicates in NPC cells, thus induces the apoptosis of NPC cells. Moreover, ORFV can effectively inhibit NPC cell growth in vivo. ORFV infection in NPC cells leads to the mTOR signaling inhibition and up-regulated autophagy, which might be the specific mechanism of ORFV in killing tumor cells. As to safety confirmation, normal nasopharyngeal epithelial cells NP69 are insensitive to ORFV. More importantly, ORFV would not cause organ damage in vivo. SIGNIFICANCES: Our data clarified that ORFV induces autophagy of NPC cells via inhibiting mTOR signaling, thus further inducing apoptosis. The anti-tumor role of ORFV might provide a preclinical strategy for NPC treatment.

Exposure to hydroxyapatite nanoparticles enhances Toll-like receptor 4 signal transduction and overcomes endotoxin tolerance in vitro and in vivo.

Emerging studies indicate hydroxyapatite nanoparticles (HANPs) exhibit modest immunogenicity to elicit innate immune response which might involve Toll-like receptor 4 (TLR4) activation. This study was proposed to elucidate how HANPs direct over TLR4 signal activity in macrophage in response to TLR4 ligand, lipopolysaccharide (LPS). The present study for the first time reveals that HANPs themselves can induce TLR4 endocytosis and activate pathways both of nuclear factor-kappa B (NF-κB) and interferon regulatory factor 3 (IRF3), which potentially trigger the production of inflammatory cytokine by macrophage. Further, HANPs dose-dependently reprogram over LPS driven TLR4 signaling transduction in macrophage, leading to synergistically augmented innate immune response. In particular, HANPs synergize with LPS to promote macrophage polarization toward M1 phenotype. Moreover, HANPs abrogate the endotoxin tolerance in macrophages by restoring the production of inflammatory cytokines from macrophage in response to secondary LPS stimulation, and enhance the responsiveness of the body to LPS re-challenge in the endotoxin tolerance mice model. Therefore, this study sheds a new light on the mechanism by which HANPs drive the innate immune response, and offers a powerful strategy to potentiate LPS mediated TLR4 signaling activation in macrophage. STATEMENT OF SIGNIFICANCE: In recent years, increasing attention has been given to hydroxyapatite nanoparticles (HANPs) on how they interact with immune cells for achieving appropriate biological effect such as bone tissue repair, soft tissue filler, tumor treatment, vaccine delivery, et al. This study indicated HANPs can induce TLR4 signaling activation. In the further, HANPs dose-dependently synergize with LPS to program over LPS induced TLR4 signaling transduction in macrophage, to favor macrophage polarizing toward M1 phenotype, as well as to abrogate immune tolerance in macrophage in response to repeated LPS stimulation. This work opens a window for the intrinsic mechanism of HANPs to drive immune response and facilitate to direct the rational use or design of HANPs for their better biomedical application.

Enhanced osteogenic activity and antibacterial performance in vitro of polyetheretherketone by plasma-induced graft polymerization of acrylic acid and incorporation of zinc ions.

Polyetheretherketone (PEEK) has been widely used in the fields of orthopedics and trauma, but weak osteointegration and bacterial infection affect its long-term stability and repair effects. Surface modification is an effective way to improve the osteogenic and antibacterial activity of PEEK implants. In the present study, a layer of acrylic acid (AA) polymer coating loaded with zinc ions (Zn2+) was constructed on the surface of PEEK (PEEK-AA-Zn) using a strategy of combining plasma-induced graft polymerization with a chemical immersion technique. Successful construction of the AA coating remarkably enhanced the hydrophilicity of PEEK, and effectively loaded and released Zn2+. In vitro cell culture using MC3T3-E1 preosteoblasts showed that the Zn2+ released from PEEK-AA-Zn promoted cell proliferation and elevated gene expression levels of alkaline phosphatase (ALP), osteocalcin (OCN) and bone sialoprotein (BSP). Antibacterial tests revealed that PEEK-AA-Zn efficiently inhibited the proliferation of Staphylococcus aureus (S. aureus). These results suggest that the combined method of graft polymerization and ion incorporation endows PEEK with excellent osteogenic and antibacterial activity, which provides a wide range of possibilities for developing PEEK implants with multifunctional properties for bone tissue repair.

The Morphology of Hydroxyapatite Nanoparticles Regulates Cargo Recognition in Clathrin-Mediated Endocytosis.

The clathrin-associated protein adaptin-2 (AP2) is a distinctive member of the hetero-tetrameric clathrin adaptor complex family. It plays a crucial role in many intracellular vesicle transport pathways. The hydroxyapatite (HAp) nanoparticles can enter cells through clathrin-dependent endocytosis, induce apoptosis, and ultimately inhibit tumor metastasis. Exploring the micro process of the binding of AP2 and HAp is of great significance for understanding the molecular mechanism of HAp's anti-cancer ability. In this work, we used molecular modeling to study the binding of spherical, rod-shaped, and needle-shaped HAps toward AP2 protein at the atomic level and found that different nanoparticles' morphology can determine their binding specificity through electrostatic interactions. Our results show that globular HAp significantly changes AP2 protein conformation, while needle-shaped HAP has more substantial binding energy with AP2. Therefore, this work offers a microscopic picture for cargo recognition in clathrin-mediated endocytosis, clarifies the design principles and possible mechanisms of high-efficiency nano-biomaterials, and provides a basis for their potential anti-tumor therapeutic effects.

Visible Light-Induced Decarboxylative Alkylation of Heterocyclic Aromatics with Carboxylic Acids via Anthocyanin as a Photocatalyst.

A visible light-induced decarboxylative alkylation of heterocyclic aromatics with aliphatic carboxylic acids was developed by using anthocyanins as a photocatalyst under mild conditions. A series of alkylated heterocyclic compounds were obtained in moderate to good yields by using the metal-free decarboxylative coupling reaction under blue light. This strategy uses cheap and readily available carboxylic acids as alkylation reagents with good functional group tolerance and environmental friendliness. It is worth noting that this is the first time that anthocyanin has been used to catalyze the Minisci-type C-H alkylation. The mechanism of decarboxylation alkylation was studied by capturing the adduct of alkyl radical and hydroquinone, thus confirming a radical mechanism. This protocol provides an alternative visible light-induced decarboxylative alkylation for the functionalization of heterocyclic aromatics.

Collagen family genes and related genes might be associated with prognosis of patients with gastric cancer: an integrated bioinformatics analysis and experimental validation.

BACKGROUND: Gastric cancer (GC) is disease with a high morbidity. The purpose of this study was to identify genes essential to GC development in patients and to reveal the underlying mechanisms of progression. METHODS: Bioinformatics analysis is an effective tool for discovering essential genes of different disease states. We used the Gene Expression Omnibus (GEO) database to identify differentially expressed genes (DEGs), the DAVID online tool to perform Gene Ontology (GO), Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis of DEGs, the STRING database to construct the protein-protein interaction (PPI) network of DEGs, the Oncomine and the Cancer Genome Atlas-Stomach Adenocarcinoma (TCGA-STAD) databases to analyze the gene expression differences, the Human pan-Cancer Methylation database (MethHC) to compare the DNA methylation of genes, and the Kaplan-Meier plotter to show the survival analysis of DEGs. We performed Real-Time quantitative PCR (RT-qPCR) experiment to confirm our analysis results. RESULTS: After the integration of four Gene Expression Series (GSEs), we identified 407 DEGs. GO and KEGG pathway analysis indicated that the upregulated DEGs were significantly enriched in Extracellular Matrix (ECM) related functions and pathways. The main DEGs were collagens (COLs). Moreover, the downregulated DEGs were enriched in ethanol oxidation. Several groups of DEGs, such as insulin-like growth factor binding protein (IGFBP), collagen (COL) and serpin peptidase inhibitors (SERPIN) gene families, constituted several PPI networks. In the Oncomine database, all of the collagen genes were highly expressed in breast cancer, esophageal cancer, GC, head and neck cancer and pancreatic cancer, compared with normal tissues. Consistently, from the TCGA-STAD database, most of the collagens (COLs) were highly expressed and exhibited methylated variation in GC patients. In GC patients, some of these collagen (COL) genes related to worse prognosis, as evidenced by the results from the Kaplan-Meier plotter database analysis. Our RT-qPCR results showed that collagen type III α1 chain (COL3A1) was highly expressed in GC cells. Collagen type V α1 chain (COL5A1) was highly expressed, except in AGS cells, which was consistent with our analysis. CONCLUSIONS: Collagen (COL) family genes might serve as progression and prognosis markers of GC.

Application of hydroxyapatite nanoparticles in tumor-associated bone segmental defect.

Hydroxyapatite (HA) has been widely applied in bone repair because of its superior biocompatibility. Recently, a proliferation-suppressive effect of HA nanoparticles (n-HA) against various cancer cells was reported. This study was aimed at assessing the translational value of n-HA both as a bone-regenerating material and as an antitumor agent. Inhibition of tumor growth, prevention of metastasis, and enhancement of the survival rate of tumor-bearing rabbits treated with n-HA were demonstrated. Activated mitochondrial-dependent apoptosis in vivo was confirmed, and we observed that a stimulated immune response was involved in the n-HA-induced antitumor effect. A porous titanium scaffold loaded with n-HA was fabricated and implanted into a critical-sized segmental bone defect in a rabbit tumor model. The n-HA-releasing scaffold not only showed a prominent effect in suppressing tumor growth and osteolytic lesion but also promoted bone regeneration. These findings provide a rationale for using n-HA in tumor-associated bone segmental defects.

A visible-light-induced cascade reaction of etherification/C-C cyclization: efficient synthesis of dibenzo[b,d]oxepin-7(6H)-ones.

A visible-light-induced palladium-catalyzed cascade reaction was developed by etherification/C-C coupling cyclization of α-bromoacetophenones with phenols. A series of dibenzo[b,d]oxepin-7(6H)-one derivatives were efficiently synthesized by using this method in good yields. Furthermore, this method was applied to the synthesis of protosappanin A. The protocol has advantages such as simple reaction conditions, wide range of substrates and high reaction efficiency.

The in vitro and in vivo anti-melanoma effects of hydroxyapatite nanoparticles: influences of material factors.

BACKGROUND: Treatment for melanoma is a challenging clinical problem, and some new strategies are worth exploring. PURPOSE: The objective of this study was to investigate the in vitro and in vivo anti-melanoma effects of hydroxyapatite nanoparticles (HANPs) and discuss the involved material factors. MATERIALS AND METHODS: Five types of HANPs, ie, HA-A, HA-B, HA-C, HA-D, and HA-E, were prepared by wet chemical method combining with polymer template and appropriate post-treatments. The in vitro effects of the as-prepared five HANPs on inhibiting the viability of A375 melanoma cells and inducing the apoptosis of the cells were evaluated by Cell Counting Kit-8 analysis, cell nucleus morphology observation, flow cytometer, and PCR analysis. The in vivo anti-melanoma effects of HANPs were studied in the tumor model of nude mice. RESULTS: The five HANPs had different physicochemical properties, including morphology, size, specific surface area (SSA), crystallinity, and so on. By the in vitro cell study, it was found that the material factors played important roles in the anti-melanoma effect of HANPs. Among the as-prepared five HANPs, HA-A with granular shape, smaller size, higher SSA, and lower crystallinity exhibited best effect on inhibiting the viability of A375 cells. At the concentration of 200 µg/mL, HA-A resulted in the lowest cell viability (34.90%) at day 3. All the HANPs could induce the apoptosis of A375 cells, and the relatively higher apoptosis rates of the cells were found in HA-A (20.10%) and HA-B (19.41%) at day 3. However, all the HANPs showed no inhibitory effect on the viability of the normal human epidermal fibroblasts. The preliminary in vivo evaluation showed that both HA-A and HA-C could delay the formation and growth speed of melanoma tissue significantly. Likely, HA-A exhibited better effect on inhibiting the growth of melanoma tissue than HA-C. The inhibition rate of HA-A for tumor tissue growth reached 49.1% at day 23. CONCLUSION: The current study confirmed the anti-melanoma effect of HANPs and provided a new idea for the clinical treatment of melanoma.