Background
Exosomes are a type of membrane vesicles secreted by living cells. Recent studies suggest exosome-like nanovesicles (ELNVs) from fruits and vegetables are involved in tissue renewal process and functional regulation against inflammatory diseases or cancers. However, there are few reports on ELNVs derived from medicinal plants.
Methods
ELNVs derived from
Asparagus cochinchinensis
(Lour.) Merr. (ACNVs) were isolated and characterized. Cytotoxicity, antiproliferative and apoptosis-inducing capacity of ACNVs against hepatoma carcinoma cell were assessed. The endocytosis mechanism of ACNVs was evaluated on Hep G2 cells in the presence of different endocytosis inhibitors. In vivo distribution of ACNVs was detected in healthy and tumor-bearing mice after scavenger receptors (SRs) blockade. PEG engineering of ACNVs was achieved through optimizing the pharmacokinetic profiles. In vivo antitumor activity and toxicity were evaluated in Hep G2 cell xenograft model.
Results
ACNVs were isolated and purified using a differential centrifugation method accompanied by sucrose gradient ultracentrifugation. The optimized ACNVs had an average size of about 119 nm and showed a typical cup-shaped nanostructure containing lipids, proteins, and RNAs. ACNVs were found to possess specific antitumor cell proliferation activity associated with an apoptosis-inducing pathway. ACNVs could be internalized into tumor cells mainly via phagocytosis, but they were quickly cleared once entering the blood. Blocking the SRs or PEGylation decoration prolonged the blood circulation time and increased the accumulation of ACNVs in tumor sites. In vivo antitumor results showed that PEGylated ACNVs could significantly inhibit tumor growth without side effects.
Conclusion
This study provides a promising functional nano platform derived from edible
Asparagus cochinchinensis
that can be used in antitumor therapy with negligible side effects.
Micropeptides are a recently discovered class of molecules that play vital roles in various cellular processes, including differentiation, proliferation, and apoptosis. Here, we sought to identify cancer-associated micropeptides and to uncover their mechanistic functions. A micropeptide named short trans-membrane protein 1 (STMP1) that localizes at the inner mitochondrial membrane was identified to be upregulated in various cancer types and associated with metastasis and recurrence of hepatocellular carcinoma. Both gain- and loss-of-function studies revealed that STMP1 increased dynamin-related protein 1 (DRP1) activation to promote mitochondrial fission and enhanced migration of tumor cells. STMP1 silencing inhibited in vivo tumor metastasis in xenograft mouse models. Overexpression of STMP1 led to redistribution of mitochondria to the leading edge of cells and enhanced lamellipodia formation. Treatment with a DRP1 inhibitor abrogated the promotive effect of STMP1 on mitochondrial fission, lamellipodia formation, and tumor cell migration in vitro and metastasis in vivo. Furthermore, STMP1 interacted with myosin heavy chain 9 (MYH9), the subunit of non-muscle myosin II, and silencing MYH9 abrogated STMP1-induced DRP1 activation, mitochondrial fission, and cell migration. Collectively, this study identifies STMP1 as a critical regulator of metastasis and a novel unit of the mitochondrial fission protein machinery, providing a potential therapeutic target for treating metastases.
Background: BF211, a derivative of bufalin (BF), shows significantly improved solubility and potent antitumor efficiency compared to BF. Unfortunately, the unwanted toxicity such as cardiotoxicity caused by unspecific distribution has hindered its clinical use. Methods: PEGylated BF211 liposomes (BF211@Lipo) were designed and optimizely prepared based on the pre-prescription research. In vitro and in vivo cardiotoxicity was evaluated. In vivo pharmacokinetics and biodistribution of BF211@Lipo were investigated. In vivo antitumor activity and toxicity were evaluated in HepG2 cell xenograft models. The rapid-release triggered by Poloxamer 188 (P188) was assessed in vitro and in vivo. Results: The optimized BF211@Lipo displayed a spherical morphology with a size of (164.6 ± 10.3) nm and a high encapsulation efficiency of (93.24 ± 2.15) %. The in vivo concentration-time curves of BF211 loaded in liposomes showed a prolonged half-life in plasma and increased tumor accumulation. No obvious abnormality in electrocardiograms was observed in guinea pigs even at 9 mg/kg. Moreover, to improve the efficient release of BF211@Lipo, a surfactant-assisted rapid-release strategy was developed, and the releasepromoting mechanism was revealed by the fluorescence resonance energy transfer (FRET) and fluorescence nanoparticle tracking analysis (fl-NTA) technology. Sequential injection of BF211@Lipo and P188 could ignite the "cold" liposomes locally in tumor regions, facilitating the burst release of BF211 and enhancing the therapeutic index. Conclusion: Our progressive efforts that begin with preparation technology and dosage regimen enable BF211 to like a drug, providing a promising nano platform to deliver the cardiac glycosides and alleviate the side effects by decreasing unspecific biodistribution.
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