9 research outputs found
A functional nanocarrier that copenetrates extracellular matrix and multiple layers of tumor cells for sequential and deep tumor autophagy inhibitor and chemotherapeutic delivery
<p>To further enhance the intensity of deep tumor drug delivery and integrate a combined therapy, we herein report on a core-shell nanocarrier that could simultaneously overcome the double barriers of the extracellular matrix (ECM) and multiple layers of tumor cells (MLTC). A pH-triggered reversible swelling-shrinking core and an MMP2 (matrix metallopeptidase 2) degradable shell were developed to encapsulate chemotherapeutics and macroautophagy/autophagy inhibitors, respectively. MMP2 degraded the shell, which was followed by the autophagy inhibitors' release. The exposed core could diffuse along the pore within the ECM to deliver chemotherapeutics into deep tumors, and it was able to swell in lysosomes and shrink back in the cytoplasm or ECM. The swelling of the core resulted in the rapid release of chemotherapeutics to kill autophagy-inhibited cells. After leaving the dead cells, the shrinking core could act on neighboring cells that were closer to the center of the tumor. The core thus could also cross MLTC layer by layer to deliver chemotherapeutics into the deep tumor.</p
Increased Gold Nanoparticle Retention in Brain Tumors by <i>in Situ</i> Enzyme-Induced Aggregation
The treatment of brain tumors remains
a challenge due to the limited
accumulation of drugs and nanoparticles. Here, we triggered the aggregation
of gold nanoparticles (AuNPs) using legumain to enhance the retention
of chemotherapeutics in brain tumors. This nanoplatform, AuNPs-A&C,
is comprised of Ala-Ala-Asn-Cys-Lys modified AuNPs (AuNPs-AK) and
2-cyano-6-aminobenzothiazole modified AuNPs (AuNPs-CABT). AuNPs-AK
could be hydrolyzed to expose the 1,2-thiolamino groups on AuNPs-AK
in the presence of legumain, which occurs by a click cycloaddition
with the contiguous cyano group on AuNPs-CABT, resulting in formation
of AuNPs aggregates. This strategy led to an enhanced retention of
the AuNPs in glioma cells both <i>in vitro</i> and <i>in vivo</i> due to the blocking of nanoparticle exocytosis and
minimizing nanoparticle backflow to the bloodstream. After conjugation
of doxorubicin (DOX) <i>via</i> a pH-sensitive linker to
AuNPs-A&C, the efficiency for treating glioma was improved. The
median survival time for the DOX-linked AuNPs-A&C increased to
288% in comparison to the saline group. We further show the use of
the AuNPs-A&C for optical imaging applications. In conclusion,
we provide a strategy to increase nanoparticle tumor accumulation
with the potential to improve therapeutic outcome
Losartan loaded liposomes improve the antitumor efficacy of liposomal paclitaxel modified with pH sensitive peptides by inhibition of collagen in breast cancer
<p>The dense collagen network in tumors restricts the penetration of drugs into tumors. Free losartan could inhibit collagen, but it would cause hypotension at the dosage of 10 mg/kg/d. In this study, losartan was encapsulated in liposomes (LST-Lip) and the collagen inhibition ability of LST-Lip was investigated. Our results showed the blood pressure was not affected by LST-Lip at the dosage of 2.5 mg/kg every other day. The amount of Evans Blue in tumor in LST-Lip group was 1.98 times of that in control group. Confocal laser scanning microscopy images showed that prior injection of LST-Lip could inhibit collagen and further improve the tumorous accumulation of liposomes modified with TH peptides (AGYLLGHINLHHLAHL(Aib)HHIL-NH<sub>2</sub>) (TH-Lip) in 4T1 tumors. Compared with control group, the tumor inhibition rate of combined strategy of LST-Lip and paclitaxel loaded TH-Lip (PTX-TH-Lip) was 41.73%, while that of group only treated with PTX-TH-Lip was 14.94%. Masson’s trichrome staining confirmed that collagen was inhibited in LST-Lip group. Thus, the administration of LST-Lip in advance could inhibit the collagen in tumors effectively and did not affect the blood pressure, then PTX-TH-Lip injected subsequently could exert enhanced antitumor efficacy. In conclusion, this combined strategy might be promising for breast cancer therapy.</p
Tandem Peptide Based on Structural Modification of Poly-Arginine for Enhancing Tumor Targeting Efficiency and Therapeutic Effect
The
nonselectivity of cell penetrating peptides had greatly limited
the application in systemic administration. By conjugating a dGR motif
to the C-terminal of octa-arginine, the formed tandem peptide R8-dGR
had been proved to specifically recognize both integrin α<sub>v</sub>β<sub>3</sub> and neuropilin-1 receptors. However, the
positive charge of poly-arginine would still inevitably lead to rapid
clearance in the circulation system. Therefore, in this study, we
tried to reduce the positive charge of poly-arginine by decreasing
the number of arginine, to thus achieve improved tumor targeting efficiency.
We had designed several different R<i>x</i>-dGR peptides
(<i>x</i> = 4, 6, and 8) modified liposomes and investigated
their tumor targeting and penetrating properties both <i>in vitro</i> and <i>in vivo</i>. Among all the liposomes, R6-dGR modified
liposomes exhibited a long circulation time similar to that of PEGylated
liposomes while they retained strong penetrating ability into both
tumor cells and tumor tissues, and thus had displayed the most superior
tumor targeting efficiency. Then, paclitaxel and indocyanine green
coloaded liposomes were prepared, and R6-dGR modified coloaded liposomes
also exhibited enhanced antitumor effect on C6 xenograft tumor bearing
mice. Therefore, we suggest R6-dGR as a potential tumor targeting
ligand with both strong penetrating ability and improved pharmacokinetic
behavior, which could be further used for efficient antitumor therapy
Cabazitaxel and indocyanine green co-delivery tumor-targeting nanoparticle for improved antitumor efficacy and minimized drug toxicity
<p>Cabazitaxel (CBX) is an effective antineoplastic agent for the treatment of many kinds of cancers. However, the poor water solubility remains a serious deterrent to the utilization of CBX as a commercial drug. In this study, we designed a strategy that integrated CBX into albumin nanoparticles (ANs) formed with human serum albumin (HSA) to improve the water solubility and targeting ability. Meanwhile, we utilized a photothermal agent-indocyanine green (ICG), which could cooperate with CBX to enhance the antitumor effect. The obtained ANs containing ICG and CBX (AN-ICG-CBX) exhibited good mono-dispersity. <i>In vitro</i> cytotoxicity study showed the effectiveness of CBX and ICG, respectively, whereas AN-ICG-CBX with irradiation exhibited the most efficient antiproliferative ability (83.7%). <i>In vivo</i> safety evaluation studies demonstrated the safety of AN-ICG-CBX. Furthermore, the <i>in vivo</i> antitumor study indicated that the AN-ICG-CBX with irradiation achieved higher tumor inhibition rate (91.3%) compared with CBX-encapsulated AN (AN-CBX) (83.3%) or ICG-encapsulated AN (AN-ICG) plus irradiation (60.1%) in 4T1 tumor-bearing mice. To sum up, a safety and effective formulation AN-ICG-CBX was developed in this study and successfully reduced the drug toxicity, improved the targeting efficiency and enhanced the therapeutic effects, becoming a promising candidate for clinical application.</p
Synergistic Dual-Ligand Doxorubicin Liposomes Improve Targeting and Therapeutic Efficacy of Brain Glioma in Animals
Therapeutic outcome for the treatment
of glioma was often limited
due to low permeability of delivery systems across the blood–brain
barrier (BBB) and poor penetration into the tumor tissue. In order
to overcome these hurdles, we developed the dual-targeting doxorubicin
liposomes conjugated with cell-penetrating peptide (TAT) and transferrin
(T7) (DOX-T7-TAT-LIP) for transporting drugs across the BBB, then
targeting brain glioma, and penetrating into the tumor. The dual-targeting
effects were evaluated by both <i>in vitro</i> and <i>in vivo</i> experiments. <i>In vitro</i> cellular
uptake and three-dimensional tumor spheroid penetration studies demonstrated
that the system could not only target endothelial and tumor monolayer
cells but also penetrate tumor to reach the core of the tumor spheroids
and inhibit the growth of the tumor spheroids. <i>In vivo</i> imaging further demonstrated that T7-TAT-LIP provided the highest
tumor distribution. The median survival time of tumor-bearing mice
after administering DOX-T7-TAT-LIP was significantly longer than those
of the single-ligand doxorubicin liposomes and free doxorubicin. In
conclusion, the dual-ligand liposomes comodified with T7 and TAT possessed
strong capability of synergistic targeted delivery of payload into
tumor cells both <i>in vitro</i> and <i>in vivo</i>, and they were able to improve the therapeutic efficacy of brain
glioma in animals
Multifunctional Tandem Peptide Modified Paclitaxel-Loaded Liposomes for the Treatment of Vasculogenic Mimicry and Cancer Stem Cells in Malignant Glioma
The chemotherapy of aggressive glioma
is usually accompanied by
a poor prognosis because of the formation of vasculogenic mimicry
(VM) and brain cancer stem cells (BCSCs). VM provided a transporting
pathway for nutrients and blood to the extravascular regions of the
tumor, and BCSCs were always related to drug resistance and the relapse
of glioma. Thus, it is important to evaluate the inhibition effect
of antiglioma drug delivery systems on both VM and BCSCs. In this
study, paclitaxel-loaded liposomes modified with a multifunctional
tandem peptide R8-cÂ(RGD) (R8-cÂ(RGD)-Lip) were used for the treatment
of glioma. An in vitro cellular uptake study proved the strongest
targeting ability to be that of R8-cÂ(RGD)-Lip to glioma stem cells.
Drug loaded R8-cÂ(RGD)-Lip exhibited an efficient antiproliferation
effect on BCSCs and could induce the destruction of VM channels in
vitro. The following pharmacodynamics study demonstrated that R8-cÂ(RGD)-modified
drug-loaded liposomes achieved both anti-VM and anti-BCSC effects
in vivo. Finally, no significant cytotoxicity of the blood system
or major organs of the drug-loaded liposomes was observed under treatment
dosage in the safety evaluation. In conclusion, all of the results
proved that R8-cÂ(RGD)-Lip was a safe and efficient antiglioma drug
delivery system
Liposomes Combined an Integrin α<sub>v</sub>β<sub>3</sub>‑Specific Vector with pH-Responsible Cell-Penetrating Property for Highly Effective Antiglioma Therapy through the Blood–Brain Barrier
Glioma,
one of the most common aggressive malignancies, has the
highest mortality in the present world. Delivery of nanocarriers from
the systemic circulation to the glioma sites would encounter multiple
physiological and biological barriers, such as blood–brain
barrier (BBB) and the poor penetration of nanocarriers into the tumor.
To circumvent these hurdles, the paclitaxel-loaded liposomes were
developed by conjugating with a TR peptide (PTX-TR-Lip), integrin
α<sub>v</sub>β<sub>3</sub>-specific vector with pH-responsible
cell-penetrating property, for transporting drug across the BBB and
then delivering into glioma. Surface plasmon resonance (SPR) studies
confirmed the very high affinity of TR-Lip and integrin α<sub>v</sub>β<sub>3</sub>. In vitro results showed that TR-Lip exhibited
strong transport ability across BBB, killed glioma cells and brain
cancer stem cells (CSCs), and destroyed the vasculogenic mimicry (VM)
channels. In vivo results demonstrated that TR-Lip could better target
glioma, and eliminated brain CSCs and the VM channels in tumor tissues.
The median survival time of tumor-bearing mice after administering
PTX-TR-Lip (45 days) was significantly longer than that after giving
free PTX (25.5 days, <i>p</i> < 0.001) or other controls.
In conclusion, PTX-TR-Lip would improve the therapeutic efficacy of
brain glioma in vitro and in vivo
Significantly enhanced tumor cellular and lysosomal hydroxychloroquine delivery by smart liposomes for optimal autophagy inhibition and improved antitumor efficiency with liposomal doxorubicin
<p>Hydroxychloroquine (HCQ) inhibits autophagy and therefore can sensitize some cancer cells to chemotherapy, but the high doses required limit its clinical use. Here we show that loading HCQ into liposomes (HCQ/Lip) decorated with a pH-sensitive TH-RGD targeting peptide (HCQ/Lip-TR) can concentrate HCQ in B16F10 tumor cells and lysosomes. HCQ/Lip-TR was efficiently internalized as a result of its ability to bind ITGAV-ITGB3/integrin α<sub>v</sub>β<sub>3</sub> receptors highly expressed on the tumor cell surface and to undergo charge reversal from anionic at pH 7.4 to cationic at pH 6.5. Studies in vitro at pH 6.5 showed that the intracellular HCQ concentration was 35.68-fold higher, and lysosomal HCQ concentration 32.22-fold higher, after treating cultures with HCQ/Lip-TR than after treating them with free HCQ. The corresponding enhancements observed in mice bearing B16F10 tumors were 15.16-fold within tumor cells and 14.10-fold within lysosomes. HCQ/Lip-TR was associated with milder anemia and milder myosuppressive reductions in white blood cell and platelet counts than free HCQ, as well as less accumulation in the small intestine, which may reduce risk of intestinal side effects. In addition, co-delivering HCQ/Lip-TR with either free doxorubicin (DOX) or liposomal DOX improved the ability of DOX to inhibit tumor growth. Biochemical, electron microscopy and immunofluorescence experiments confirmed that HCQ/Lip-TR blocked autophagic flux in tumor cells. Our results suggest that loading HCQ into Lip-TR liposomes may increase the effective concentration of the inhibitor in tumor cells, allowing less toxic doses to be used.</p