Eudragit S100 prepared pH-responsive liposomes-loaded betulinic acid against colorectal cancer in vitro and in vivo.

This study aimed to develop polymer Eudragit S100 for preparing pH-responsive liposomes-loaded betulinic acid (pH-BA-LP) to improve the therapeutic index of chemotherapy for colorectal cancer. BA-loaded liposomes were coated with Eudragit S100 by a thin film dispersion and easily scalable pH-driven method. The prepared liposomes were evaluated for size, surface morphology, entrapment efficiency, stability, in vitro drug release, and antitumor activity. In particular, pH-BA-LP showed advantages such as lower size (<100 nm), encapsulation efficiency of 90%, high stability, and stably cumulative release. By detecting the antitumor effects of pH-BA-LP in vivo, it showed that the tumor proliferation and cell migration were significantly inhibited in colorectal cancer. The pH-BA-LP also inhibited tumor growth via the regulation of Akt/TLR-mediated signalling and significantly down-regulated the expression of NFAT1 and NFAT4 proteins. It was found that pH-BA-LP can increase NK cells and CD3+ cells in tumor tissues, and the proportion of CD8+ cells in CD3+ cells was also increased, which proved that pH-BA-LP can play an antitumor effect by enhancing the autoimmunity level in tumor-bearing mice. The positive infiltration rates of CD8 and CD68 were increased and CD163 was relatively decreased by using pH-BA-LP, which proved that pH-BA-LP can regulate the immune infiltration levels in tumor-bearing mice. Therefore, the present work provides an effective method to prepare pH-responsive polymer-coated liposomes for colonic delivery with biologically active compounds.

The effects and mechanisms of isoliquiritigenin loaded nanoliposomes regulated AMPK/mTOR mediated glycolysis in colorectal cancer.

In this study, isoliquiritigenin (ISL) incorporated nanoliposomes were prepared and their effects on colorectal cancer (CRC) cell lines were investigated. Herein, we sought to explore the anti-cancer mechanisms of ISL loaded nanoliposomes (ISL-NLs) on AMP-activated protein kinase/mammalian target of rapamycin (AMPK/mTOR) pathways mediated glycolysis. Also, the key targets such as caveolin 1 (CAV1), glucose transporters and Akt/mTOR that promote glycolysis, and are activated via the induction of α-enolase (ENO1), fructose bisphosphate aldolase A (ALDOA) and monocarboxylate transporter 4 (MCT4) expressions were also investigated. It was shown that ISL-NLs significantly suppressed the proliferation and glucose uptake of CRC cell by potentially regulating the glycolysis and lactate targets as well as pathways that formed the basis of the anti-CRC effects of ISL-NLs. The mechanism underlying this effect was further validated via the regulation of some key targets such as ENO1, ALDOA, lactate dehydrogenase A (LDHA) and MCT4 in glycolysis coupled with cellular myelocytomatosis oncogene (c-myc), hypoxia-inducible factor 1-alpha (HIF-1α) in protein kinase B/mTOR (Akt/mTOR) pathways. Moreover, the AMPK proteins were identified to be up-regulated while the lactic acid production was suppressed by ISL-NLs in the CRC cells, indicating that ISL-NLs had an inhibitory effect on AMPK mediated glycolysis and lactate production. Altogether, these results have provided insights into the mechanism underlying the key role that liposomal ISL played in the multiple inhibition of AMPK and Akt/mTOR mediated glycolysis and lactate generation, which may be regulated as the alternative metabolic pathways of CRC as well as serve as adjuvant therapy for the disease.

Effects and mechanisms of fatty acid metabolism­mediated glycolysis regulated by betulinic acid­loaded nanoliposomes in colorectal cancer.

Although previous studies have demonstrated that triterpenoids, such as betulinic acid (BA), can inhibit tumor cell growth, their potential targets in colorectal cancer (CRC) metabolism have not been systematically investigated. In the present study, BA­loaded nanoliposomes (BA­NLs) were prepared, and their effects on CRC cell lines were evaluated. The aim of the present study was to determine the anticancer mechanisms of action of BA­NLs in fatty acid metabolism­mediated glycolysis, and investigate the role of key targets, such as acyl­CoA synthetase (ACSL), carnitine palmitoyltransferase (CPT) and acetyl CoA, in promoting glycolysis, which is activated by inducing hexokinase (HK), phosphofructokinase­1 (PFK­1), phosphoenolpyruvate (PEP) and pyruvate kinase (PK) expression. The results demonstrated that BA­NLs significantly suppressed the proliferation and glucose uptake of CRC cells by regulating potential glycolysis and fatty acid metabolism targets and pathways, which forms the basis of the anti­CRC function of BA­NLs. Moreover, the effects of BA­NLs were further validated by demonstrating that the key targets of HK2, PFK­1, PEP and PK isoenzyme M2 (PKM2) in glycolysis, and of ACSL1, CPT1a and PEP in fatty acid metabolism, were blocked by BA­NLs, which play key roles in the inhibition of glycolysis and fatty acid­mediated production of pyruvate and lactate. The results of the present study may provide a deeper understanding supporting the hypothesis that liposomal BA may regulate alternative metabolic pathways implicated in CRC adjuvant therapy.

Increasing the anticancer performance of bufalin (BUF) by introducing an endosome-escaping polymer and tumor-targeting peptide in the design of a polymeric prodrug.

A well-defined multifunctional brush-type polymeric prodrug covalently linked with an anticancer drug (bufalin, BUF), a tumor-targeting peptide (RGD), and an endosome-escaping polymer, poly(N,N-diethylaminoethyl methacrylate-co-butyl methacrylate (P(DEA-co-BMA)), was developed. Its anticancer performance against colon cancer was investigated in vitro and in vivo. Reversible addition-fragmentation transfer (RAFT) polymerization of oligo(ethylene glycol) monomethyl ether methacrylate (OEGMA), 2-((3-(tert-butoxy)-3-oxopropyl)thio)ethyl methacrylate (BSTMA), and 2-(2-bromoisobutyryloxy)ethylmethacrylate (BIEM) afforded the multifunctional random copolymer, P(OEGMA-co-BSTMA-co-BIEM), in which hydrophilic POEGMA can stabilize nanoparticles in water, PBSTMA can be converted into carboxyl groups, and PBIEM can be employed as a macromolecular atom radical transfer polymerization (ATRP) initiator. The ATRP of DEA and BMA using P(OEGMA-co-BSTMA-co-BIEM) as a macromolecular ATRP initiator led to the formation of the pH-responsive brush-type copolymer, P(OEGMA-co-BSTMA)-g-P(DEA-co- BMA). After hydrolysis by trifluoroacetic acid and post-functionalization the final polymeric prodrug, P(OEGMA-co-BUF-co-RGD)-g-P(DEA-co-BMA), was obtained with a drug content of ∼7.8 wt%. P(OEGMA-co-BUF-co-RGD)-g-P(DEA-co-BMA) can be assembled into nanoparticles (BUF- NP-RGD) in aqueous solution with a diameter of 148.4 ±â€¯0.7 nm and a zeta potential of -7.6 ±â€¯0.4 mV. BUF-NP-RGD exhibited controlled drug release in the presence of esterase. Additionally, P(OEGMA-co- BSMA)-g-P(DEA-co-BMA) showed a significant hemolysis effect at a pH comparable to that of endosomes/lysosomes. Cell viability and a tumor-bearing nude mouse model were employed to evaluate the anticancer efficacy of BUF-NP-RGD. It was revealed that BUF-NP-RGD showed improved anticancer performance compared with that of free BUF both in vitro and in vivo. Histological and immunochemical analysis further demonstrated that BUF-NP-RGD exhibited improved cell apoptosis, angiogenesis inhibition, and an anti-proliferation effect.

Preparation of bufalin-loaded pluronic polyetherimide nanoparticles, cellular uptake, distribution, and effect on colorectal cancer.

A large number of studies have shown that bufalin can have a significant antitumor effect in a variety of tumors. However, because of toxicity, insolubility in water, fast metabolism, short half-life, and other shortcomings, its application is limited in cancer therapy. In this study, we explored the anti-metastatic role of bufalin-loaded pluronic polyetherimide nanoparticles on HCT116 colon cancer-bearing mice. Nanoparticle size, shape, drug loading, encapsulation efficiency, and in vitro drug release were studied. Also, cellular uptake of nanoparticles, in vivo tumor targeting, and tumor metastasis were studied. The nanoparticles had a particle size of about 60 nm and an encapsulation efficiency of 75.71%, by weight. The in vitro release data showed that free bufalin was released faster than bufalin-loaded pluronic polyetherimide nanoparticles, and almost 80% of free bufalin was released after 32 hours. Nanoparticles had an even size distribution, were stable, and had a slow release and a tumor-targeting effect. Bufalin-loaded pluronic polyetherimide nanoparticles can significantly inhibit the growth and metastasis of colorectal cancer.