David Oupicky

Near-infrared light-triggered drug release from a multiple lipid carrier complex using an all-in-one strategy

Abstract The present study reports a drug delivery system comprising nanostructured lipid carrier (NLCs) within liposomes (Lip‐NLCs). This multiple lipid carrier complex features laser‐triggered responsive drug release. Both hydrophobic and hydrophilic drugs can be loaded into the same formulation by applying an all‐in‐one strategy. We hypothesized that if we loaded the hydrophobic near‐infrared (NIR) dye IR780 into the liposome phospholipid bilayer, the bilayer would be disrupted by laser irradiation so that drug release would be triggered remotely at the tumor site. We used in vitro and in vivo methods to verify that laser irradiation facilitated controlled release of both hydrophobic and hydrophilic drugs. The degree of drug release triggered by NIR laser light could be adjusted by varying the laser intensity and irradiation time. Following laser treatment, hydrophilic AMD3100 was released from the aqueous liposome chamber and then bound with CXCR4 receptors on the tumor cell surface to inhibit metastasis. NLCs carrying lipophilic IR780 were also released from the aqueous chamber of liposomes and taken up into tumor cells to enhance the photothermal therapeutic effect of IR780. More importantly, Lip‐NLCs loaded with IR780 and AMD3100 (IR780‐AMD‐Lip‐NLCs) exhibited enhanced anti‐tumor and anti‐metastasis effects. These results suggest that Lip‐NLCs are a safe and simply prepared all‐in‐one platform for delivery of drugs with different solubilities. This system facilitates easily controlled release of cargoes to achieve multi‐functional combined therapy. Graphical abstract Figure. No Caption available.

Dual-function nanostructured lipid carriers to deliver IR780 for breast cancer treatment: Anti-metastatic and photothermal anti-tumor therapy

Cancer treatments that use a combination of approaches with the ability to affect multiple disease pathways have proven highly effective. The present study reports on CXCR4-targeted nanostructured lipid carriers (NLCs) with a CXCR4 antagonist AMD3100 in the shell (AMD-NLCs). AMD-NLCs loaded with IR780 (IR780-AMD-NLCs) reduced the invasiveness of cancer cells, while simultaneously mediating efficient tumor targeting and photothermal therapeutic outcomes. We present the combined effect of encapsulated IR780 on photothermal therapy and of the AMD3100 coating on tumor targeting, CXCR4 antagonism and inhibition of cancer cell invasion and breast cancer lung metastasis in vitro and in vivo. IR780-AMD-NLCs exhibited excellent IR780 loading capacity and AMD3100 coating efficiency. The photothermal properties of IR780 were improved by encapsulation in NLCs. The encapsulated IR780 displayed better heat generating efficiency than free IR780 when exposed to repeated laser irradiation. CXCR4 antagonism and cell invasion assays confirmed that IR780-AMD-NLCs fully inhibited CXCR4 while IR780-NLCs did not function as CXCR4 antagonists. AMD3100-coated NLCs accumulated at high levels in tumors, as judged by in vivo imaging and biodistribution assays. Furthermore, CXCR4-targeted NLCs exhibited an encouraging photothermal anti-tumor effect as well as anti-metastatic efficacy in vivo. These findings suggest that this simple and stable CXCR4-targeted IR780 delivery system holds great promise for prevention of metastasis and for photothermal treatment of tumors. STATEMENT OF SIGNIFICANCE Breast cancer is a major threat to human health, it is not the primary breast tumor that is ultimately responsible for the majority of deaths, but the tumor metastasis, which frequently follows a specific pattern of dissemination. We report development of a novel dual-function nanostructured lipid carrier (NLC) for breast cancer treatment. The carrier encapsulates NIR dye IR780 in its core and contains antagonist of the chemokine receptor CXCR4 in its shell. Our results show that by combining the CXCR4 antagonism with photothermal effect of the dye leads to remarkable antitumor and antimetastatic activity in syngeneic orthotopic model of metastatic breast cancer. Furthermore, the developed system also shows a theranostic potential due to NIR fluorescence of the encapsulated dye.

Emerging roles of the CXCL12/CXCR4 axis in pancreatic cancer progression and therapy

ABSTRACT Chemokine networks regulate a variety of cellular, physiological, and immune processes. These normal functions can become appropriated by cancer cells to facilitate a more hospitable niche for aberrant cells by enhancing growth, proliferation, and metastasis. This is especially true in pancreatic cancer, where chemokine signaling is a vital component in the development of the supportive tumor microenvironment and the signaling between the cancer cells and surrounding stromal cells. Although expression patterns vary among cancer types, the chemokine receptor CXCR4 has been implicated in nearly every major malignancy and plays a prominent role in pancreatic cancer development and progression. This receptor, in conjunction with its primary chemokine ligand CXCL12, promotes pancreatic cancer development, invasion, and metastasis through the management of the tumor microenvironment via complex crosstalk with other pathways. Thus, CXCR4 likely contributes to the poor prognoses observed in patients afflicted with this malignancy. Recent exploration of combination therapies with CXCR4 antagonists have demonstrated improved outcomes, and abolishing the contribution of this pathway may prove crucial to effectively treat pancreatic cancer at both the primary tumor and metastases.

Synthesis and characterization of valproic acid ester pro-drug micelles via an amphiphilic polycaprolactone block copolymer design

The attachment of Histone deacetylase (HDAC) inhibitors via covalent bonds to biocompatible and biodegradable block copolymers provides a new research direction for cancer treatment. Herein, we report the synthesis and characterization of valproic acid ester pro-drug micelles of amphiphilic polycaprolactone block copolymers and their potential applications in drug delivery.

Biochemical evaluation of the anticancer potential of the polyamine-based nanocarrier Nano 11047

Synthesizing polycationic polymers directly from existing drugs overcomes the drug-loading limitations often associated with pharmacologically inert nanocarriers. We recently described nanocarriers formed from a first-generation polyamine analogue, bis(ethyl)norspermine (BENSpm), that could simultaneously target polyamine metabolism while delivering therapeutic nucleic acids. In the current study, we describe the synthesis and evaluation of self-immolative nanocarriers derived from the second-generation polyamine analogue PG-11047. Polyamines are absolutely essential for proliferation and their metabolism is frequently dysregulated in cancer. Through its effects on polyamine metabolism, PG-11047 effectively inhibits tumor growth in cancer cell lines of multiple origins as well as in human tumor mouse xenografts. Promising clinical trials have been completed verifying the safety and tolerance of this rotationally restricted polyamine analogue. We therefore used PG-11047 as the basis for Nano11047, a biodegradable, prodrug nanocarrier capable of targeting polyamine metabolism. Following exposure of lung cancer cell lines to Nano11047, uptake and intracellular degradation into the parent compound PG-11047 was observed. The release of PG-11047 highly induced the polyamine catabolic enzyme activities of spermidine/spermine N1-acetyltransferase (SSAT) and spermine oxidase (SMOX). By contrast, the activity of ornithine decarboxylase (ODC), a rate-limiting enzyme in polyamine biosynthesis and a putative oncogene, was decreased. Consequently, intracellular levels of the natural polyamines were depleted concurrent with tumor cell growth inhibition. This availability of Nano11047 as a novel drug form and potential nucleic acid delivery vector will potentially benefit and encourage future clinical studies.

Bioreduction-ruptured nanogel for switch on/off release of Bcl2 siRNA in breast tumor therapy

&NA; In present study, gene concentrated as well as bioreduction‐ruptured nanogel with local enrichment positive charge while low cytotoxicity was developed for Bcl2 siRNA delivery featured in intracellular switch on/off controlled release. Dynamic covalent bond crosslinked nanogel was formed by thiolated PEI of 1.8 kDa(PEI‐1.8 kDa)and biodegradable dextrin. Once nanogel was uptake by tumor cells, high concentration of glutathione (GSH) in cytosol could bioreducible ‐degrade and rupture the crosslink of this dextrin nanogel (DSP) into hypotoxic PEI‐1.8 kDa and dextrin, following by burst release of packed siRNA and minimizing the restriction of polymer material for siRNA transcription. This switch on/off siRNA release strategy for gene therapy exhibited equal level of the deregulation of Bcl2 protein expression determined by western blot analysis compared with cationic PEI with 25 kDa molecular weight (PEI‐25 kDa) in vitro. Moreover, the gene concentrated DSP based on hypotoxic PEI‐1.8 kDa and biodegradable dextrin could be administrated intravenously for systematic therapy on safely. Tumor suppression study of DSP also exhibited a superior antitumor activity in 4T1‐luc tumor cell bearing BALB/C mice. Furthermore, it exhibited lower cytotoxicity, almost none hemotoxicity, moreover avoiding recognition and clearance by RES system in healthy mice. Overall, these findings suggest that this reduction‐sensitive while bioreduction‐ruptured polymer nanogel is an innovative strategy and holds great promise for gene and drug delivery.

ATP-activated decrosslinking and charge-reversal vectors for siRNA delivery and cancer therapy

Stimuli-responsive polycations have been developed for improved nucleic acid transfection and enhanced therapeutic efficacy. The most reported mechanisms for controlled release of siRNA are based on polyelectrolyte exchange reactions in the cytoplasm and the degradation of polycations initiated by specific triggers. However, the degradation strategy has not always been sufficient due to unsatisfactory kinetics and binding of cationic fragments to siRNA, which limits the gene silencing effect. In this study, a new strategy that combines degradation and charge reversal is proposed. Methods: We prepared a polycation (CrossPPA) by crosslinking of phenylboronic acid (PBA)-grafted 1.8k PEI with alginate. It was compared with 25k PEI, 1.8k PEI and 1.8k PEI-PBA on siRNA encapsulation, ATP-responsive behavior and mechanism, cytotoxicity, cell uptake, siRNA transfection, in vivo biodistribution and in vivo anti-tumor efficacy. The in vitro and in vivo experiments were performed on 4T1 murine breast cancer cells and 4T1 tumor model separately. Results: The crosslinking strategy obviously improve the siRNA loading ability of 1.8k PEI. We validated that intracellular levels of ATP could trigger CrossPPA disassembly and charge reversal, which resulted in efficient and rapid siRNA release due to electrostatic repulsion. Besides, CrossPPA/siRNA showed strong cell uptake in 4T1 cells compared with 1.8k PEI/siRNA. Notably, the cytotoxicity of CrossPPA was pretty low, which was owing to its biodegradability. Furthermore, the crosslinked polyplexes significantly enhanced siRNA transfection and improved tumor accumulation. The high gene silencing ability of CrossPPA polyplex led to strong anti-tumor efficacy when using Bcl2-targeted siRNA. Conclusion: These results indicated that the ATP-triggered disassembly and charge reversal strategy provided a new way for developing stimuli-responsive siRNA carriers and showed potential for nucleic acid delivery in the treatment of cancer.

Cholangiocarcinoma therapy with nanoparticles that combine downregulation of MicroRNA-210 with inhibition of cancer cell invasiveness

Cholangiocarcinoma (CCA) is the second most common primary liver malignancy with extremely poor therapeutic outcome due to high drug resistance, widespread metastasis and lack of effective treatment options. CCA progression and metastasis are regulated by multiple biological factors including multiple miRNAs and chemokine receptor CXCR4. The goal of this study was to test if nanotherapeutic blockade of CXCR4 by polymeric CXCR4 antagonist (PCX) combined with inhibition of hypoxia-inducible miR-210 cooperatively enhances therapeutic efficacy in CCA through reducing invasiveness, inducing cell killing, and reversing drug resistance. Methods: We first tested the activity of PCX to inhibit migration of CCA cells. We then prepared PCX/anti-miRNA nanoparticles and analyzed their miRNA delivery efficacy and anticancer activity in vitro. Finally, in vivo biodistribution assay and anticancer activity study were performed in CCA tumor-bearing mice. Results: Our results show that PCX had a broad inhibitory effect on cell migration, effectively delivered anti-miR-210, and downregulated miR-210 expression in CCA cells. Combination PCX/anti-miR-210 nanoparticles showed cytotoxic activity towards CCA cells and reduced the number of cancer stem-like cells. The nanoparticles reversed hypoxia-induced drug resistance and sensitized CCA cells to standard gemcitabine and cisplatin combination treatment. Systemic intravenous treatment with the nanoparticles in a CCA xenograft model resulted in prominent combined antitumor activity. Conclusion: Our findings support PCX-based nanoparticles as a promising delivery platform of therapeutic miRNA in combination CCA therapies.

Near-infrared light-activated IR780-loaded liposomes for anti-tumor angiogenesis and Photothermal therapy

Tumor angiogenesis is a key step in the process of tumor development, and antitumor angiogenesis has a profound influence on tumor growth. Herein we report a dual-function drug delivery system comprising a Near-infrared (NIR) dye and an anti-angiogenic drug within liposomes (Lip-IR780-Sunitinib) for enhanced antitumor therapy. The hydrophobic NIR dye IR780 was loaded into the liposome phospholipid bilayer, and the bilayer would be disrupted by laser irradiation so that anti-angiogenic drug sunitinib release would be activated remotely at the tumor site. The released hydrophilic sunitinib could potentially target multiple VEGF receptors on the tumor endothelial cell surface to inhibit angiogenesis. Meanwhile, IR780-loaded liposomes kill the cancer cells by photothermal therapy. Lip-IR780-Sunitinib exhibited enhanced anti-tumor and anti-angiogenic effects in vitro and in vivo. This system facilitates easy and controlled release of cargos to achieve anti-tumor angiogenesis and photothermal therapy.

A networked swellable dextrin nanogels loading Bcl2 siRNA for melanoma tumor therapy

In this study, a networked swellable dextrin nanogel (DNG) was developed to achieve stimulated responsive small interfering RNA (siRNA) release for melanoma tumor therapy. siRNA was loaded into multidimensional dextrin nanogels by charge condensation with positive arginine residues modified in the dextrin backbone. Moreover, the networked nanogel was destroyed and loosened based on its bioreducible responsive property to control accelerated siRNA release in a bioreducible intracellular environment, while it remained stable under normal physiological conditions. We demonstrated that DNGs had swellable and disassembly properties under reduced buffer condition by transmission electron microscopy evaluation. The DNGs achieved an endosomal escape followed by selective release of the cargo into the cytosol by glutathione-triggered disassembly according to confocal microscopy observation. Thus, this smart nanogel achieved outstanding luciferase gene silencing efficiency and decreased Bcl2 protein expression in vitro and in vivo based on western blot analysis. Moreover, this nanogel exhibited superior anti-tumor activity for B16F10 xenograft tumors in C57BL/6 mice. These results demonstrate that the networked DNGs are effective for gene condensation and controlled intracellular release for tumor therapy. Overall, these findings suggest that this multidimensional swellable stimuli-responsive dextrin nanogel is an innovative strategy with great promise for gene and drug delivery.