Optimizing the design and in vitro evaluation of bioreactive glucose oxidase-microspheres for enhanced cytotoxicity against multidrug resistant breast cancer cells

Trends and challenges in microfluidic methods for protein manipulation-A review

Proteins are important molecules involved in an immensely large number of biological processes. Being capable of manipulating proteins is critical for developing reliable and affordable techniques to analyze and/or detect them. Such techniques would enable the production of therapeutic agents for the treatment of diseases or other biotechnological applications (e.g., bioreactors or biocatalysis). Microfluidic technology represents a potential solution to protein manipulation challenges because of the diverse phenomena that can be exploited to achieve micro- and nanoparticle manipulation. In this review, we discuss recent contributions made in the field of protein manipulation in microfluidic systems using different physicochemical principles and techniques, some of which are miniaturized versions of already established macro-scale techniques.

Advances on Delivery of Cytotoxic Enzymes as Anticancer Agents

Cancer is one of the most serious human diseases, causing millions of deaths worldwide annually, and, therefore, it is one of the most investigated research disciplines. Developing efficient anticancer tools includes studying the effects of different natural enzymes of plant and microbial origin on tumor cells. The development of various smart delivery systems based on enzyme drugs has been conducted for more than two decades. Some of these delivery systems have been developed to the point that they have reached clinical stages, and a few have even found application in selected cancer treatments. Various biological, chemical, and physical approaches have been utilized to enhance their efficiencies by improving their delivery and targeting. In this paper, we review advanced delivery systems for enzyme drugs for use in cancer therapy. Their structure-based functions, mechanisms of action, fused forms with other peptides in terms of targeting and penetration, and other main results from in vivo and clinical studies of these advanced delivery systems are highlighted.

Advances in Nanomedicine Design: Multidisciplinary Strategies for Unmet Medical Needs

Globally, a rising burden of complex diseases takes a heavy toll on human lives and poses substantial clinical and economic challenges. This review covers nanomedicine and nanotechnology-enabled advanced drug delivery systems (DDS) designed to address various unmet medical needs. Key nanomedicine and DDSs, currently employed in the clinic to tackle some of these diseases, are discussed focusing on their versatility in diagnostics, anticancer therapy, and diabetes management. First-hand experiences from our own laboratory and the work of others are presented to provide insights into strategies to design and optimize nanomedicine- and nanotechnology-enabled DDS for enhancing therapeutic outcomes. Computational analysis is also briefly reviewed as a technology for rational design of controlled release DDS. Further explorations of DDS have illuminated the interplay of physiological barriers and their impact on DDS. It is demonstrated how such delivery systems can overcome these barriers for enhanced therapeutic efficacy and how new perspectives of next-generation DDS can be applied clinically.

Enhanced in vitro anticancer activity of yeast expressed recombinant glucose oxidase versus commercial enzyme

Cancer treatments continue to have many disadvantages. Reactive oxygen species, such as H₂O₂, in high concentrations, can cause cytotoxicity to cells, being even greater in cancer cells. One of the H₂O₂-producing enzymes is glucose oxidase; its application in cancer treatment should be explored. In this work, the extracellular expression of the mutated recombinant enzyme glucose oxidase was carried out in the eukaryotic expression system Pichia pastoris SMD1168, through the modification and optimization of the gox gene of Aspergillus niger to improve its expression in yeast and its purification. Also, the secretion signal of the alpha-mating factor from Saccharomyces cerevisiae was added to the gene for extracellular expression, and it was inserted into the expression vector pPIC3.5k. The extracellular expression of the enzyme facilitated purification by anion exchange chromatography; the purification was corroborated by SDS-PAGE, with a molecular weight of its subunit between 63 kDa and 100 kDa. The mutated recombinant enzyme glucose oxidase showed greater anticancer activity compared to the commercial glucose oxidase and could have potential for cancer treatment. KEY POINTS: • Pichia pastoris is an excellent eukaryotic expression system for proteins that need post-translational modifications. • Extracellular expression facilitates protein purification. • Glucose oxidase has potential application in cancer treatment.

Co-delivery of DOX and PDTC by pH-sensitive nanoparticles to overcome multidrug resistance in breast cancer

Chemotherapeutic drugs have a series of limitations in the conventional clinical treatments, mainly including serious adverse effects and multidrug resistance (MDR). Herein, we developed a pH-sensitive polymeric nanoparticle with using poly(ortho ester urethanes) copolymers for co-delivering doxorubicin (DOX) and pyrrolidinedithiocarbamate (PDTC) to settle these problems. Dual-drug-loaded nanoparticles were nano-sized (˜220 nm) with the spherical morphology and excellent physiological stability. Both drugs both could be quickly released in the mild acidic conditions due to the cleavage of ortho ester bonds. Monolayer cultured cells (2D) and multicellular spheroids (3D) experiments proved that PDTC could reverse multidrug resistance (MDR), improve intracellular drugs accumulation and enhance tumor penetration by down-regulating the expression of P-gp, then resulting in higher DOX-induced cytotoxicity and apoptosis in MCF-7 and MCF-7/ADR cells. Besides, in vivo experiments further demonstrated that co-encapsulated nanoparticles had higher DOX accumulation and superiorer tumor growth inhibition (TGI 82.9%) than free drugs or single-drug-loaded nanoparticles on MCF-7/ADR bearing-mice. Accordingly, the pH-sensitive co-delivery systems possess a promising potential to overcome MDR in cancer therapy.

Glucose-responsive mesoporous silica nanoparticles to generation of hydrogen peroxide for synergistic cancer starvation and chemistry therapy

Background: The combination of novel starving therapy with chemotherapy is one of the most promising strategies to achieve an effective antitumor activity.

Methods: Herein, we developed a multifunctional mesoporous silica nanoparticle (MSNs-GOx/PLL/HA) coated with poly (L-lysine) (PLL) and hyaluronic acid (HA) for co-delivery of glucose oxidase (GOx) and anticancer drug paclitaxel (PTX) for cancer treatment for the first time. Compared to single chemotherapy, introduction of GOx would not only selectively trigger the consumption of intracellular glucose, leading to the interruption of energy supply, but also elevat the endogenous H₂O₂ level, inducing stronger therapeutic effects.

Results: The novel drug delivery system possessed desirable particle diameter of 40 nm and exhibited a pH-sensitive drug release behavior. An in vitro cellular uptake study indicated that MSNs-GOx/PLL/HA nanoparticles effectively enhanced the cellular uptake of drug in an apparently CD44 receptor-dependent manner, and delivered more cargo into cytoplasm via endolysosomal escape effect in presence of PLL. The nanoplatform has also demonstrated amplified synergistic therapeutic effects for remarkable tumor inhibition in a xenograft animal tumor model.

Conclusion: Consequently, the developed synergistic starving-like/chemotherapy may provide a potential platform for next generation cancer therapy.

Novel Ligustrazine-Based Analogs of Piperlongumine Potently Suppress Proliferation and Metastasis of Colorectal Cancer Cells in Vitro and in Vivo

Piperlongumine 1 increases reactive oxygen species (ROS) levels and preferably induces cancer cell apoptosis by triggering different pathways. However, the poor solubility of 1 limits its intensive investigation and clinical application. Ligustrazine possesses a water-soluble pyrazine skeleton and can inhibit proliferation and metastasis of cancer cells. We synthesized compound 3 by replacement of the trimethoxyphenyl of 1 with ligustrazine moiety and further introduced 2-Cl, -Br, and -I to 3 for synthesis of 4-6, respectively. Compound 4 possessed 14-fold greater aqueous solubility than 1 and increased ROS levels in colorectal cancer HCT-116 cells. Additionally, 4 preferably inhibited proliferation, migration, invasion, and heteroadhesion of HCT-116 cells. Treatment with 4 suppressed tumor growth and lung metastasis in vivo and prolonged the survival of tumor-bearing mice. Furthermore, 4 mitigated TGF-β1-induced epithelial-mesenchymal transition and Wnt/β-catenin activation by inhibiting the Akt and GSK-3β phosphorylation in HCT-116 cells. Collectively, 4 displayed significant antiproliferation and antimetastasis activities, superior to 1.

Recent progress in the structural modification and pharmacological activities of ligustrazine derivatives

Ligustrazine is a main active fraction of the traditional medicine known as Ligusticum chuanxiong hort, which has been used as clinical medication for cerebral thrombosis, coronary heart disease and stenocardia recently. The rapid metabolism and short half-life of ligustrazine seriously limits its application in clinical practice. Therefore, derivatives of ligustrazine are designed and synthesized in our and other labs, including piperazine, cinnamic acid, styrene, acylguanidine, amides, curcumin and triterpenes derivatives of ligustrazine. Most of these compounds present better pharmacodynamics activities and more favorable pharmacokinetic properties compared to the parent compound. Besides, some new biological activities of these compounds are discovered. Hence, this review continues the previous review of our group as well as aims to highlight recent prominent advances in this field in the past ten years.

Disulfiram anti-cancer efficacy without copper overload is enhanced by extracellular H2O2 generation: antagonism by tetrathiomolybdate

Highlights

Background

Cu/Zn superoxide dismutases (SODs) like the extracellular SOD3 and cytoplasmic SOD1 regulate cell proliferation by generating hydrogen peroxide (H₂O₂). This pro-oxidant inactivates essential cysteine residues in protein tyrosine phosphatases (PTP) helping receptor tyrosine kinase activation by growth factor signaling, and further promoting downstream MEK/ERK linked cell proliferation. Disulfiram (DSF), currently in clinical cancer trials is activated by copper chelation, being potentially capable of diminishing the copper dependent activation of MEK1/2 and SOD1/SOD3 and promoting reactive oxygen species (ROS) toxicity. However, copper (Cu) overload may occur when co-administered with DSF, resulting in toxicity and mutagenicity against normal tissue, through generation of the hydroxyl radical (•OH) by the Fenton reaction.

Purpose

To investigate: a) whether sub-toxic DSF efficacy can be increased without Cu overload against human melanoma cells with unequal BRAF(V600E) mutant status and Her2-overexpressing SKBR3 breast cancer cells, by increasing H₂O₂from exogenous SOD; b) to compare the anti-tumor efficacy of DSF with that of another clinically used copper chelator, tetrathiomolybdate (TTM)

Results

a) without copper supplementation, exogenous SOD potentiated sub-toxic DSF toxicity antagonized by sub-toxic TTM or by the anti-oxidant N-acetylcysteine; b) exogenous glucose oxidase, another H₂O₂ generator resembled exogenous SOD in potentiating sub-toxic DSF.

Conclusions

potentiation of sub-lethal DSF toxicity by extracellular H₂O₂ against the human tumor cell lines investigated, only requires basal Cu and increased ROS production, being unrelated to non-specific or TTM copper chelator sequestration.

Significance

These findings emphasize the relevance of extracellular H₂O₂ as a novel mechanism to improve disulfiram anticancer effects minimizing copper toxicity.

Discovery of New Monocarbonyl Ligustrazine-Curcumin Hybrids for Intervention of Drug-Sensitive and Drug-Resistant Lung Cancer

The elevation of oxidative stress preferentially in cancer cells by inhibiting thioredoxin reductase (TrxR) and/or enhancing reactive oxygen species (ROS) production has emerged as an effective strategy for selectively targeting cancer cells. In this study, we designed and synthesized 21 ligustrazine-curcumin hybrids (10a-u). Biological evaluation indicated that the most active compound 10d significantly inhibited the proliferation of drug-sensitive (A549, SPC-A-1, LTEP-G-2) and drug-resistant (A549/DDP) lung cancer cells but had little effect on nontumor lung epithelial-like cells (HBE). Furthermore, 10d suppressed the TrxR/Trx system and promoted intracellular ROS accumulation and cancer cell apoptosis. Additionally, 10d inhibited the NF-κB, AKT, and ERK signaling, P-gp-mediated efflux of rhodamine 123, P-gp ATPase activity, and P-gp expression in A549/DDP cells. Finally, 10d repressed the growth of implanted human drug-resistant lung cancer in mice. Together, 10d acts a novel TrxR inhibitor and may be a promising candidate for intervention of lung cancer.