Polymeric micelles containing reversibly phospholipid-modified anti-survivin siRNA: a promising strategy to overcome drug resistance in cancer

Overview of role of survivin in cancer: expression, regulation, functions, and its potential as a therapeutic target

Survivin holds significant importance as a member of the inhibitor of apoptosis protein (IAP) family due to its predominant expression in tumours rather than normal terminally differentiated adult tissues. The high expression level of survivin in tumours is closely linked to chemotherapy resistance, heightened tumour recurrence, and increased tumour aggressiveness and serves as a negative prognostic factor for cancer patients. Consequently, survivin has emerged as a promising therapeutic target for cancer treatment. In this review, we delve into the various biological characteristics of survivin in cancers and its pivotal role in maintaining immune system homeostasis. Additionally, we explore different therapeutic strategies aimed at targeting survivin.

Advances in siRNA Drug Delivery Strategies for Targeted TNBC Therapy

Among breast cancers, triple-negative breast cancer (TNBC) has been recognized as the most aggressive type with a poor prognosis and low survival rate. Targeted therapy for TNBC is challenging because it lacks estrogen receptor (ER), progesterone receptor (PR), and human epidermal growth factor receptor 2 (HER2). Chemotherapy, radiation therapy, and surgery are the common therapies for TNBC. Although TNBC is prone to chemotherapy, drug resistance and recurrence are commonly associated with treatment failure. Combination therapy approaches using chemotherapy, mAbs, ADC, and antibody-siRNA conjugates may be effective in TNBC. Recent advances with siRNA-based therapy approaches are promising for TNBC therapy with better prognosis and reduced mortality. This review discusses advances in nanomaterial- and nanobiomaterial-based siRNA delivery platforms for TNBC therapy exploring targeted therapy approaches for major genes, proteins, and TFs upregulated in TNBC tumors, which engage in molecular pathways associated with low TNBC prognosis. Bioengineered siRNA drugs targeting one or several genes simultaneously can downregulate desired genes, significantly reducing disease progression.

Anti-BIRC5 autoantibody serves as a valuable biomarker for diagnosing AFP-negative hepatocellular carcinoma

Background

Autoantibodies targeting tumor-associated antigens (TAAbs) have emerged as promising biomarkers for early cancer detection. This research aimed to assess the diagnostic capacity of anti-BIRC5 autoantibody in detecting AFP-negative hepatocellular carcinoma (ANHCC).

Methods

This research was carried out in three stages (discovery phase, validation phase, and evaluation phase) and included a total of 744 participants. Firstly, the anti-BIRC5 autoantibody was discovered using protein microarray, exhibiting a higher positive rate in ANHCC samples (ANHCCs) compared to normal control samples (NCs). Secondly, the anti-BIRC5 autoantibody was validated through enzyme-linked immunosorbent assay (ELISA) in 85 ANHCCs and 85 NCs from two clinical centers (Zhengzhou and Nanchang). Lastly, the diagnostic usefulness of the anti-BIRC5 autoantibody for hepatocellular carcinoma (HCC) was evaluated by ELISA in a cohort consisting of an additional 149 AFP-positive hepatocellular carcinoma samples (APHCCs), 95 ANHCCs and 244 NCs. The association of elevated autoantibody to high expression of BIRC5 in HCC was further explored by the database from prognosis, immune infiltration, DNA methylation, and gene mutation level.

Results

In the validation phase, the area under the ROC curve (AUC) of anti-BIRC5 autoantibody to distinguish ANHCCs from NCs in Zhengzhou and Nanchang centers was 0.733 and 0.745, respectively. In the evaluation phase, the AUCs of anti-BIRC5 autoantibody for identifying ANHCCs and HCCs from NCs were 0.738 and 0.726, respectively. Furthermore, when combined with AFP, the AUC for identifying HCCs from NCs increased to 0.914 with a sensitivity of 77.5% and specificity of 91.8%. High expression of BIRC5 gene is not only correlated with poor prognosis of HCCs, but also significantly associated with infiltration of immune cells, DNA methylation, and gene mutation.

Conclusion

The findings suggest that the anti-BIRC5 autoantibody could serve as a potential biomarker for ANHCC, in addition to its supplementary role alongside AFP in the diagnosis of HCC. Next, we can carry out specific verification and explore the function of anti-BIRC5 autoantibody in the occurrence and development of HCC.

Lipid nanoparticles for RNA delivery: Self-assembling vs driven-assembling strategies

Among non-viral vectors, lipid nanovectors are considered the gold standard for the delivery of RNA therapeutics. The success of lipid nanoparticles for RNA delivery, with three products approved for human use, has stimulated further investigation into RNA therapeutics for different pathologies. This requires decoding the pathological intracellular processes and tailoring the delivery system to the target tissue and cells. The complexity of the lipid nanovectors morphology originates from the assembling of the lipidic components, which can be elicited by various methods able to drive the formation of nanoparticles with the desired organization. In other cases, pre-formed nanoparticles can be mixed with RNA to induce self-assembly and structural reorganization into RNA-loaded nanoparticles. In this review, the most relevant lipid nanovectors and their potentialities for RNA delivery are described on the basis of the assembling mechanism and of the particle architecture.

Development and Perspectives: Multifunctional Nucleic Acid Nanomedicines for Treatment of Gynecological Cancers

Gynecological malignancies are a significant cause of morbidity and mortality across the globe. Due to delayed presentation, gynecological cancer patients are often referred late in the disease's course, resulting in poor outcomes. A considerable number of patients ultimately succumb to chemotherapy-resistant disease, which reoccurs at advanced stages despite treatment interventions. Although efforts have been devoted to developing therapies that demonstrate reduced resistance to chemotherapy and enhanced toxicity profiles, current clinical outcomes remain unsatisfactory due to treatment resistance and unfavorable off-target effects. Consequently, innovative biological and nanotherapeutic approaches are imperative to strengthen and optimize the therapeutic arsenal for gynecological cancers. Advancements in nanotechnology-based therapies for gynecological malignancies offer significant advantages, including reduced toxicity, expanded drug circulation, and optimized therapeutic dosing, ultimately leading to enhanced treatment effectiveness. Recent advances in nucleic acid therapeutics using microRNA, small interfering RNA, and messenger RNA provide novel approaches for cancer therapeutics. Effective single-agent and combinatorial nucleic acid therapeutics for gynecological malignancies have the potential to transform cancer treatment by giving safer, more tailored approaches than conventional therapies. This review highlights current preclinical studies that effectively exploit these approaches for the treatment of gynecological malignant tumors and malignant ascites.

Polymeric-Micelle-Based Delivery Systems for Nucleic Acids

Nucleic acids can modulate gene expression specifically. They are increasingly being utilized and show huge potential for the prevention or treatment of various diseases. However, the clinical translation of nucleic acids faces many challenges due to their rapid clearance after administration, low stability in physiological fluids and limited cellular uptake, which is associated with an inability to reach the intracellular target site and poor efficacy. For many years, tremendous efforts have been made to design appropriate delivery systems that enable the safe and effective delivery of nucleic acids at the target site to achieve high therapeutic outcomes. Among the different delivery platforms investigated, polymeric micelles have emerged as suitable delivery vehicles due to the versatility of their structures and the possibility to tailor their composition for overcoming extracellular and intracellular barriers, thus enhancing therapeutic efficacy. Many strategies, such as the addition of stimuli-sensitive groups or specific ligands, can be used to facilitate the delivery of various nucleic acids and improve targeting and accumulation at the site of action while protecting nucleic acids from degradation and promoting their cellular uptake. Furthermore, polymeric micelles can be used to deliver both chemotherapeutic drugs and nucleic acid therapeutics simultaneously to achieve synergistic combination treatment. This review focuses on the design approaches and current developments in polymeric micelles for the delivery of nucleic acids. The different preparation methods and characteristic features of polymeric micelles are covered. The current state of the art of polymeric micelles as carriers for nucleic acids is discussed while highlighting the delivery challenges of nucleic acids and how to overcome them and how to improve the safety and efficacy of nucleic acids after local or systemic administration.

Polymeric micelles and cancer therapy: an ingenious multimodal tumor-targeted drug delivery system

Since the beginning of pharmaceutical research, drug delivery methods have been an integral part of it. Polymeric micelles (PMs) have emerged as multifunctional nanoparticles in the current technological era of nanocarriers, and they have shown promise in a range of scientific fields. They can alter the release profile of integrated pharmacological substances and concentrate them in the target zone due to their improved permeability and retention, making them more suitable for poorly soluble medicines. With their ability to deliver poorly soluble chemotherapeutic drugs, PMs have garnered considerable interest in cancer. As a result of their remarkable biocompatibility, improved permeability, and minimal toxicity to healthy cells, while also their capacity to solubilize a wide range of drugs in their micellar core, PMs are expected to be a successful treatment option for cancer therapy in the future. Their nano-size enables them to accumulate in the tumor microenvironment (TME) via the enhanced permeability and retention (EPR) effect. In this review, our major aim is to focus primarily on the stellar applications of PMs in the field of cancer therapeutics along with its mechanism of action and its latest advancements in drug and gene delivery (DNA/siRNA) for cancer, using various therapeutic strategies such as crossing blood-brain barrier, gene therapy, photothermal therapy (PTT), and immunotherapy. Furthermore, PMs can be employed as "smart drug carriers," allowing them to target specific cancer sites using a variety of stimuli (endogenous and exogenous), which improve the specificity and efficacy of micelle-based targeted drug delivery. All the many types of stimulants, as well as how the complex of PM and various anticancer drugs react to it, and their pharmacodynamics are also reviewed here. In conclusion, commercializing engineered micelle nanoparticles (MNPs) for application in therapy and imaging can be considered as a potential approach to improve the therapeutic index of anticancer drugs. Furthermore, PM has stimulated intense interest in research and clinical practice, and in light of this, we have also highlighted a few PMs that have previously been approved for therapeutic use, while the majority are still being studied in clinical trials for various cancer therapies.

Emerging Nanotherapeutic Approaches to Overcome Drug Resistance in Cancers with Update on Clinical Trials

A key issue with modern cancer treatments is the emergence of resistance to conventional chemotherapy and molecularly targeted medicines. Cancer nanotherapeutics were created in order to overcome the inherent limitations of traditional chemotherapeutics. Over the last few decades, cancer nanotherapeutics provided unparalleled opportunities to understand and overcome drug resistance through clinical assessment of rationally designed nanoparticulate delivery systems. In this context, various design strategies such as passive targeting, active targeting, nano-drug, and multimodal nano-drug combination therapy provided effective cancer treatment. Even though cancer nanotherapy has made great technological progress, tumor biology complexity and heterogeneity and a lack of comprehensive knowledge of nano-bio interactions remain important roadblocks to future clinical translation and commercialization. The current developments and advancements in cancer nanotherapeutics employing a wide variety of nanomaterial-based platforms to overcome cancer treatment resistance are discussed in this article. There is also a review of various nanotherapeutics-based approaches to cancer therapy, including targeting strategies for the tumor microenvironment and its components, advanced delivery systems for specific targeting of cancer stem cells (CSC), as well as exosomes for delivery strategies, and an update on clinical trials. Finally, challenges and the future perspective of the cancer nanotherapeutics to reverse cancer drug resistance are discussed.

Targeted siRNA nanotherapeutics against breast and ovarian metastatic cancer: a comprehensive review of the literature

Metastasis is considered the major cause of unsuccessful cancer therapy. The metastatic development requires tumor cells to leave their initial site, circulate in the blood stream, acclimate to new cellular environments at a remote secondary site and endure there. There are several steps in metastasis, including invasion, intravasation, circulation, extravasation, premetastatic niche formation, micrometastasis and metastatic colonization. siRNA therapeutics are appreciated for their usefulness in treatment of cancer metastasis. However, siRNA therapy as a single therapy may not be a sufficient option for control of metastasis. By combining siRNA with targeting, functional agents or small-molecule drugs have shown potential effects that enhance therapeutic effectiveness. This review addresses multidrug resistance and metastasis in breast and ovarian cancers and highlights drug-delivery strategies using siRNA therapeutics.

Recent Advances in Gene Therapy for Cancer Theranostics

There is great interest in developing gene therapies for many disease indications, including cancer. However, successful delivery of nucleic acids to tumor cells is a major challenge, and in vivo efficacy is difficult to predict. Cancer theranostics is an approach combining anti-tumor therapy with imaging or diagnostic capabilities, with the goal of monitoring successful delivery and efficacy of a therapeutic agent in a tumor. Successful theranostics must maintain a high degree of anticancer targeting and efficacy while incorporating high-contrast imaging agents that are nontoxic and compatible with clinical imaging modalities. This review highlights recent advancements in theranostic strategies, including imaging technologies and genetic engineering approaches. Graphical Abstract.

Multifunctional polymeric micellar nanomedicine in the diagnosis and treatment of cancer

Polymeric micelles are a prevalent topic of research for the past decade, especially concerning their fitting ability to deliver drug and diagnostic agents. This delivery system offers outstanding advantages, such as biocompatibility, high loading efficiency, water-solubility, and good stability in biological fluids, to name a few. The multifunctional polymeric micellar architect offers the added capability to adapt its surface to meet the looked-for clinical needs. This review cross-talks the recent reports, proof-of-concept studies, patents, and clinical trials that utilize polymeric micellar family architectures concerning cancer targeted delivery of anticancer drugs, gene therapeutics, and diagnostic agents. The manuscript also expounds on the underlying opportunities, allied challenges, and ways to resolve their bench-to-bedside translation for allied clinical applications.

Nanomedicines for combating multidrug resistance of cancer

Chemotherapy typically involves the use of specific chemodrugs to inhibit the proliferation of cancer cells, but the frequent emergence of a variety of multidrug-resistant cancer cells poses a tremendous threat to our combat against cancer. The fundamental causes of multidrug resistance (MDR) have been studied for decades, and can be generally classified into two types: one is associated with the activation of diverse drug efflux pumps, which are responsible for translocating intracellular drug molecules out of the cells; the other is linked with some non-efflux pump-related mechanisms, such as antiapoptotic defense, enhanced DNA repair ability, and powerful antioxidant systems. To overcome MDR, intense efforts have been made to develop synergistic therapeutic strategies by introducing MDR inhibitors or combining chemotherapy with other therapeutic modalities, such as phototherapy, gene therapy, and gas therapy, in the hope that the drug-resistant cells can be sensitized toward chemotherapeutics. In particular, nanotechnology-based drug delivery platforms have shown the potential to integrate multiple therapeutic agents into one system. In this review, the focus was on the recent development of nanostrategies aiming to enhance the efficiency of chemotherapy and overcome the MDR of cancer in a synergistic manner. Different combinatorial strategies are introduced in detail and the advantages as well as underlying mechanisms of why these strategies can counteract MDR are discussed. This review is expected to shed new light on the design of advanced nanomedicines from the angle of materials and to deepen our understanding of MDR for the development of more effective anticancer strategies. This article is categorized under: Nanotechnology Approaches to Biology > Nanoscale Systems in Biology Therapeutic Approaches and Drug Discovery > Nanomedicine for Oncologic Disease.

Synergistic Effect of Doxorubicin and siRNA-Mediated Silencing of Mcl-1 Using Cationic Niosomes against 3D MCF-7 Spheroids

Chemotherapy is a vital option for cancer treatment; however, its therapeutic outcomes are limited by dose-dependent toxicity and the occurrence of chemoresistance. siRNAs have emerged as an attractive therapeutic option enabling specific interference with target genes. Combination therapy using chemotherapeutic agents along with gene therapy could be a potential strategy for cancer management, which not only improves therapeutic efficacy but also decreases untoward effects from dose reduction. In this study, a cationic niosome containing plier-like cationic lipid B was used to convey siRNA against anti-apoptotic mRNA into MCF-7 and MDA-MB-231 cells. Mcl-1 silencing markedly decreased the viability of MCF-7 cells and triggered apoptosis. Moreover, computer modeling suggested that the combination of doxorubicin (Dox) and Mcl-1 siRNA exhibited a synergistic relationship and enabled a dose reduction of each agent at 1.71 and 3.91 folds, respectively, to reach a 90% inhibitory effect when compared to single-agent treatments. Synergistic antitumor activity was further verified in a 3D spheroid culture which revealed, in contrast to single-agent treatment, the combination markedly decreased spheroid volume over time. Together, the combination therapy between Mcl-1 silencing and Dox exhibits a synergistic effect that may be exploited for novel breast cancer treatment.

Bioengineered siRNA-Based Nanoplatforms Targeting Molecular Signaling Pathways for the Treatment of Triple Negative Breast Cancer: Preclinical and Clinical Advancements

Triple negative breast cancer (TNBC) is one of the most aggressive types of breast cancer. Owing to the absenteeism of hormonal receptors expressed at the cancerous breast cells, hormonal therapies and other medications targeting human epidermal growth factor receptor 2 (HER2) are ineffective in TNBC patients, making traditional chemotherapeutic agents the only current appropriate regimen. Patients' predisposition to relapse and metastasis, chemotherapeutics' cytotoxicity and resistance and poor prognosis of TNBC necessitates researchers to investigate different novel-targeted therapeutics. The role of small interfering RNA (siRNA) in silencing the genes/proteins that are aberrantly overexpressed in carcinoma cells showed great potential as part of TNBC therapeutic regimen. However, targeting specificity, siRNA stability, and delivery efficiency cause challenges in the progression of this application clinically. Nanotechnology was highlighted as a promising approach for encapsulating and transporting siRNA with high efficiency-low toxicity profile. Advances in preclinical and clinical studies utilizing engineered siRNA-loaded nanotherapeutics for treatment of TNBC were discussed. Specific and selective targeting of diverse signaling molecules/pathways at the level of tumor proliferation and cell cycle, tumor invasion and metastasis, angiogenesis and tumor microenvironment, and chemotherapeutics' resistance demonstrated greater activity via integration of siRNA-complexed nanoparticles.

Cytotoxicity of Novel Redox Sensitive PEG2000-S-S-PTX Micelles against Drug-Resistant Ovarian and Breast Cancer Cells

PURPOSE

Since the last decade, it is established that nonspecific delivery of chemotherapeutics fails to effectively treat cancer due to systemic cytotoxicity, poor biodistribution at tumor site and most importantly the development of drug resistance (MDR). Stimuli-sensitive drug delivery systems gained significant attention in recent years for effective tumor therapy and reversal of MDR. The aim of this study was developing a redox sensitive micellar prodrug system, by taking the advantage of the significant difference in GSH levels between extracellular and intracellular environments, but more importantly in healthy and tumor tissues.

METHODS

Redox sensitive PEG₂₀₀₀-S-S-PTX micelles were developed for intracellular paclitaxel delivery and characterized in vitro. In vitro release studies were carried out and followed by cytotoxicity studies in chemo-resistant ovarian and breast cancer cells in various reducing environments for different time periods to confirm their potential.

RESULTS

PEG₂₀₀₀-S-S-PTX, was synthesized and characterized as a redox sensitive micellar prodrug system. The reduction sensitivity and in vitro PTX release properties were confirmed in reducing environments comparatively with physiological conditions. Cytotoxicity studies suggested that ovarian (SK-OV-3) cells could be better candidates for treatment with redox-sensitive drug delivery systems than breast (MCF-7) cancer cells.

CONCLUSIONS

The results of this study highlights the importance of personalized therapy since no fits-for-all system can be developed for different cancer with significantly different metabolic activities. Graphical Abstract Schematic representation of self-assembly of reduction-sensitive PEG2000-S-S-PTX micelles and GSH dependent release of PTX.

Codelivery of DOX and siRNA by folate-biotin-quaternized starch nanoparticles for promoting synergistic suppression of human lung cancer cells

In this paper, the self-assembled folate-biotin-quaternized starch nanoparticles (FBqS NPs) were used as carrier system of doxorubicin (DOX) and siRNAIGF1R for the codelivery of both into human lung adenocarcinoma cell lines (A549 cells) in vitro. The cytotoxicity, targeted ligand competition, cell proliferation inhibition, cellular uptake, endocytosis mechanism and target protein suppression of drug-loaded FBqS NPs were evaluated in detail. Compared with several other drug formulations under same condition, siRNAIGF1R/DOX/FBqS NPs exhibited the greatest cytotoxicity to A549 cells and the cytotoxicity was competitively inhibited by free folate in dose-dependent manner. The A549 cells treated by siRNAIGF1R/DOX/FBqS NPs showed the lowest cell proliferation capacity. The energy-dependent clathrin- and caveolae-mediated endocytosis might be the primary cellular uptake mechanism of drug-loaded FBqS NPs. The expression of IGF1R protein in A549 cells treated by siRNAIGF1R/FBqS NPs declined dramatically. So the FBqS NPs were expected as the co-carrier system of chemotherapeutants and siRNAs for future clinical application.

Cancer therapeutics using survivin BIRC5 as a target: what can we do after over two decades of study?

Survivin (also named BIRC5) is a well-known cancer therapeutic target. Since its discovery more than two decades ago, the use of survivin as a target for cancer therapeutics has remained a central goal of survivin studies in the cancer field. Many studies have provided intriguing insight into survivin's functional role in cancers, thus providing promise for survivin as a cancer therapeutic target. Despite this, moving survivin-targeting agents into and through the clinic remains a challenge. In order to address this challenge, we may need to rethink current strategies in order to develop a new mindset for targeting survivin. In this Review, we will first summarize the current survivin mechanistic studies, and then review the status of survivin cancer therapeutics, which is classified into five categories: (i) survivin-partner protein interaction inhibitors, (ii) survivin homodimerization inhibitors, (iii) survivin gene transcription inhibitors, (iv) survivin mRNA inhibitors and (v) survivin immunotherapy. We will then provide our opinions on cancer therapeutics using survivin as a target, with the goal of stimulating discussion that might facilitate translational research for discovering improved strategies and/or more effective anticancer agents that target survivin for cancer therapy.

Multifunctional drug carrier based on PEI derivatives loaded with small interfering RNA for therapy of liver cancer

Gene therapy strategies for liver cancer have broad application prospects but still lack a stable and efficient delivery vehicle. To overcome this obstacle, we designed a multifunctional gene delivery vector, sTPssOLP, which was based on oleylamine (OA)-modified disulfide-containing polyethylenimine (PEI) and incorporated into lipids to prepare a lipid nanoparticle. sTPssOLP consisted of the core of PEI derivative and cationic lipids bound to siRNA. The modified polyethylene glycol (PEG) and transferrin (Tf) were partially embedded in the phospholipid bilayer through the lipid and the other as the outer shell. The aim was to use the redox responsiveness of disulfide to trigger siRNA release in cytoplasm to enhance transfection efficiency. Pegylated lipids and Tf focus on increasing cycle life in the body and increasing accumulation at the tumor site of the carrier. In addition, two vectors were prepared as controls, one based on a PEI derivative containing no disulfide bond (POLP) and the other on the surface of the carrier not linked to Tf (PssOLP). PEI derivatives effectively avoid the toxicity problems caused by the use of PEI alone (25 kDa). Meanwhile, it was confirmed by gel retardation experiments that in the presence of dithiothreitol (DTT), the disulfide bond can indeed be reduced and the siRNA entrapped in the vector can be released. Both HepG2 and SMMC had significant uptake of sTPssOLP. The results of intracellular and lysosomal co-localization indicated that sTPssOLP achieved lysosomal escape. RT-PCR and Western blot results also confirmed that sTPssOLP had the best gene silencing activity. In vivo, the tumor inhibition rate of sTPssOLP in nude mice carrying HepG2 xenografts was 56%, which was significantly greater than that of the saline control group. In vivo imaging results showed that fluorescently labeled siRNA loaded in sTPssOLP was able to deliver more to the tumor site. At the same time, it was observed that sTPssOLP did not show significant damage to normal tissues. Therefore, this multifunctional gene delivery vector warrants further investigation.

Design, mechanism, delivery and therapeutics of canonical and Dicer-substrate siRNA

Upon the discovery of RNA interference (RNAi), canonical small interfering RNA (siRNA) has been recognized to trigger sequence-specific gene silencing. Despite the benefits of siRNAs as potential new drugs, there are obstacles still to be overcome, including off-target effects and immune stimulation. More recently, Dicer substrate siRNA (DsiRNA) has been introduced as an alternative to siRNA. Similarly, it also is proving to be potent and target-specific, while rendering less immune stimulation. DsiRNA is 25–30 nucleotides in length, and is further cleaved and processed by the Dicer enzyme. As with siRNA, it is crucial to design and develop a stable, safe, and efficient system for the delivery of DsiRNA into the cytoplasm of targeted cells. Several polymeric nanoparticle systems have been well established to load DsiRNA for in vitro and in vivo delivery, thereby overcoming a major hurdle in the therapeutic uses of DsiRNA. The present review focuses on a comparison of siRNA and DsiRNA on the basis of their design, mechanism, in vitro and in vivo delivery, and therapeutics.

Enhanced endosomal escape by photothermal activation for improved small interfering RNA delivery and antitumor effect

BACKGROUND

Effective endosomal escape is still a critical bottleneck for intracellular delivery of small interfering RNAs (siRNAs) to maximize their therapeutic efficacy. To overcome this obstacle, we have developed a photothermally triggered system by using the near-infrared (NIR) irradiation to achieve "on-demand" endosomal escape and subsequent siRNA release into cytoplasm.

MATERIALS AND METHODS

Herein, the poly-L-lysine (PLL) was successfully conjugated with melanin to obtain melanin-poly-L-lysine (M-PLL) polymer as a siRNA vehicle. The melanin was an efficient photothermal sensitizer, and the positive pendant amino groups of PLL could condense siRNAs to form stable complexes by electrostatic interactions.

RESULTS AND DISCUSSION

Inspired by its excellent photothermal conversion efficiency, the melanin was first involved in the siRNA delivery system. Confocal laser scanning microscopic observation revealed that after cellular uptake the photothermally induced endosomal escape could facilitate siRNAs to overcome endosomal barrier and be delivered into cytoplasm, which resulted in significant silence in the luciferase expression over the NIR- and melanin-free controls. Moreover, the anti-survivin siRNA-loaded M-PLL nanoparticles displayed great inhibitory effect on 4T1 tumor growth in vitro and in vivo.

CONCLUSION

These findings suggest that the M-PLL-mediated siRNA delivery is a promising candidate for therapeutic siRNA delivery and shows improved effect for cancer therapy via enhanced endosomal escape.

Micelle-like nanoparticles as siRNA and miRNA carriers for cancer therapy

Gene therapy has emerged as an alternative in the treatment of cancer, particularly in cases of resistance to chemo and radiotherapy. Different approaches to deliver genetic material to tumor tissues have been proposed, including the use of small non-coding RNAs due to their multiple mechanisms of action. However, such promise has shown limits in in vivo application related to RNA's biological instability and stimulation of immunity, urging the development of systems able to overcome those barriers. In this review, we discuss the use of RNA interference in cancer therapy with special attention to the role of siRNA and miRNA and to the challenges of their delivery in vivo. We introduce a promising class of drug delivery system known as micelle-like nanoparticles and explore their synthesis and advantages for gene therapy as well as the recent findings in in vitro, in vivo and clinical studies.

Evaluation of the potential of a simplified co-delivery system with oligodeoxynucleotides as a drug carrier for enhanced antitumor effect

Background

We previously developed a simple effective system based on oligodeoxynucleotides with CGA repeating units (CGA-ODNs) for Dox and siRNA intracellular co-delivery.

Methods

In the present study, the in vitro cytotoxicity, gene transfection and in vivo safety of the co-delivery system were further characterized and discussed.

Results

Compared with poly(ethyleneimine) (PEI), both CGA-ODNs and the pH-sensitive targeted coating, o-carboxymethyl-chitosan (CMCS)-poly(ethylene glycol) (PEG)-aspargine-glycine-arginine (NGR) (CMCS-PEG-NGR, CPN) showed no obvious cytotoxicity in 72 h. The excellent transfection capability of CPN coated Dox and siRNA co-loaded nanoparticles (CPN-PDR) was confirmed by real-time PCR and Western blot analysis. It was calculated that there was no significant difference in silencing efficiency among Lipo/siRNA, CPN-modified siRNA-loaded nanoparticles (CPN-PR) and CPN-PDR. Furthermore, CPN-PDR was observed to be significantly much more toxic than Dox- and CPN-modified Dox-loaded nanoparticles (CPN-PD), implying their higher antitumor potential. Both hemolysis tests and histological assessment implied that CPN-PDR was safe for intravenous injection with nontoxicity and good biocompatibility in vitro and in vivo.

Conclusion

The results indicated that CPN-PDR could be a potentially promising co-delivery carrier for enhanced antitumor therapy.

Polymer Vesicles: Modular Platforms for Cancer Theranostics

As an emerging field that is receiving an increasing amount of interest, theranostics is becoming increasingly important in the field of nanomedicine. Among the various smart platforms that have been proposed for use in theranostics, polymer vesicles (or polymersomes) are among the most promising candidates for integration of designated functionalities and modalities. Here, a brief summary of typical theranostic platforms is presented with a focus on modular polymer vesicles. To highlight modularity, the different methodologies for designing therapeutic and diagnostic modules are classified and current examples of theranostic vesicles that excel in both performance and design principle are provided. Finally, future prospects for theranostic polymer vesicles that can be readily prepared with functional modules are proposed. Overall, theranostic polymer vesicles with modular modalities and functions are more promising in nanomedicine than simply being "over-engineered".

Redox-responsive polymeric micelles formed by conjugating gambogic acid with bioreducible poly(amido amine)s for the co-delivery of docetaxel and MMP-9 shRNA

A novel redox-sensitive system for co-delivering hydrophobic drugs and hydrophilic siRNA or shRNA was developed by conjugating gambogic acid (GA) with poly(amido amine)s (PAAs) through amide bonds, which is called GA-conjugated PAAs (PAG). PAG can self-assemble into micelles as amphiphilic block copolymers, which exhibits an excellent loading ability for the co-delivery of docetaxel (DTX) and MMP-9 shRNA with adjustable dosing ratios. In addition, confocal microscopy, flow cytometry and in vitro transfection analyses demonstrated more efficient cellular internalization of DTX and MMP-9 shRNA after incubation with PAG/DTX- MMP-9 shRNA micelles (PAG/DTX-shRNA) than with free drugs. Unlike traditional amphiphilic copolymer micelles, GA conjugated in PAG possesses an intrinsic anticancer efficacy. The presence of disulfide bonds in PAAs enables rapid disassembly of PAG micelles in response to reducing agents, inducing the release of loaded drugs (DTX, GA and MMP-9 shRNA). In vitro cellular assays revealed that PAG/DTX-shRNA micelles inhibited MCF-7 cell proliferation more efficiently than the single drug or single drug-loaded micelles. In vivo biodistribution and anti-tumor effect studies using an MCF-7 breast cancer xenograft mouse model have indicated that PAG/DTX-shRNA micelles can enhance drug accumulation compared with the free drug, thereby sustaining the therapeutic effect on tumors. Additionally, PAG/DTX-shRNA micelles displayed a greater anti-tumor efficacy than Taxotere® and PAG-shRNA micelles. These results suggest that the redox-sensitive PAG platform is a promising co-delivery system for combining drugs and gene therapy for the treatment of cancer.

STATEMENT OF SIGNIFICANCE

The PAG micelles were designed by conjugating gambogic acid (GA) with poly(amido amine)s (PAAs), which would serve dual purposes as both gene and drugs co-delivery carrier and an anti-tumor prodrug. Unlike traditional amphiphilic micelles, GA conjugated in PAG could exert its intrinsic efficacy and provide synergistic antiproliferative effects with docetaxel (DTX) on MCF-7 cells. Disulfide bonds in PAG enables a rapid disassembly of PAG micelles in response to reducing agents and to release all loaded drugs (DTX, GA and MMP-9 shRNA) at tumor sites. PAG/DTX-shRNA micelles displayed greater anti-tumor efficacy than that of Taxotere®, indicating the design concept for PAG works well. And the strategy for PAG could be used to develop a series of similar co-delivery systems through conjugations of other small-molecule drugs with PAAs, such as doxorubicin, methotrexate and other drugs with carboxy groups in their structure.

Bioorthogonal strategies for site-directed decoration of biomaterials with therapeutic proteins

Emerging strategies targeting site-specific protein modifications allow for unprecedented selectivity, fast kinetics and mild reaction conditions with high yield. These advances open exciting novel possibilities for the effective bioorthogonal decoration of biomaterials with therapeutic proteins. Site-specificity is particularly important to the therapeutics' end and translated by targeting specific functional groups or introducing new functional groups into the therapeutic at predefined positions. Biomimetic strategies are designed for modification of therapeutics emulating enzymatic strategies found in Nature. These strategies are suitable for a diverse range of applications - not only for protein-polymer conjugation, particle decoration and surface immobilization, but also for the decoration of complex biomaterials and the synthesis of bioresponsive drug delivery systems. This article reviews latest chemical and enzymatic strategies for the biorthogonal decoration of biomaterials with therapeutic proteins and inter-positioned linker structures. Finally, the numerous reports at the interface of biomaterials, linkers, and therapeutic protein decoration are integrated into practical advice for design considerations intended to support the selection of productive ligation strategies.

Redox-triggered intracellular siRNA delivery

Stimuli-sensitive nanoformulation achieved successful intracellular siRNA delivery and GFP downregulation due to GSH-triggered disulfide bond breakage and PEG-de-shielding without toxicity.

Nanotechnology-based combination therapy for overcoming multidrug-resistant cancer

Multidrug resistance (MDR) is a major obstacle to successful cancer treatment and is crucial to cancer metastasis and relapse. Combination therapy is an effective strategy for overcoming MDR. However, the different pharmacokinetic (PK) profiles of combined drugs often undermine the combination effect in vivo, especially when greatly different physicochemical properties (e.g., those of macromolecules and small drugs) combine. To address this issue, nanotechnology-based codelivery techniques have been actively explored. They possess great advantages for tumor targeting, controlled drug release, and identical drug PK profiles. Thus, a powerful tool for combination therapy is provided, and the translation from in vitro to in vivo is facilitated. In this review, we present a summary of various combination strategies for overcoming MDR and the nanotechnology-based combination therapy.

Highlights in nanocarriers for the treatment against cervical cancer

Cervical cancer is the second most common malignant tumor in women worldwide and has a high mortality rate, especially when it is associated with human papillomavirus (HPV). In US, an estimated 12,820 cases of invasive cervical cancer and an estimated 4210 deaths from this cancer will occur in 2017. With rare and very aggressive conventional treatments, one sees in the real need of new alternatives of therapy as the delivery of chemotherapeutic agents by nanocarriers using nanotechnology. This review covers different drug delivery systems applied in the treatment of cervical cancer, such as solid lipid nanoparticles (SNLs), liposomes, nanoemulsions and polymeric nanoparticles (PNPs). The main advantages of drug delivery thus improving pharmacological activity, improving solubility, bioavailability to bioavailability reducing toxicity in the target tissue by targeting of ligands, thus facilitating new innovative therapeutic technologies in a too much needed area. Among the main disadvantage is the still high cost of production of these nanocarriers. Therefore, the aim this paper is review the nanotechnology based drug delivery systems in the treatment of cervical cancer.

[Role of SOX4 on DDP Resistance in Non-small Cell Lung Cancer Cell of A549]

背景与目的

肺癌是最严重的恶性肿瘤之一，其中非小细胞肺癌发病率在肺癌中居首位。部分患者对顺铂耐受是导致化疗失败的主要原因。SOX4是转录调节因子，在多种肿瘤的发生发展过程中发挥着重要的作用，通过调控β-catenin的表达对Wnt信号通路进行调控。本研究旨在探讨SOX4对非小细胞肺癌细胞A549的顺铂耐药作用的影响。

方法

体外诱导法建立顺铂耐药的肺癌细胞株A549/DDP，CCK8法检测A549及A549/DDP细胞对顺铂的耐药性。绘制A549与A549/DDP细胞生长曲线。Western blot检测耐药细胞株中SOX4的蛋白表达水平。CCK8法检测敲减SOX4后耐药细胞株A549/DDP对顺铂耐药性。实时定量PCR和免疫印迹法检测敲减SOX4后A549/DPP细胞中β-catenin和Survivin蛋白的表达。

结果

成功构建非小细胞肺癌顺铂耐药细胞株A549/DDP，其耐药性是亲本细胞的13.7倍，差异有统计学意义（P < 0.001）。生长曲线显示耐药细胞株与亲本细胞增殖速度没有统计学差异（P < 0.05）；与A549细胞相比，耐药细胞A549/DDP细胞中SOX4的表达显著增高（P < 0.001）。敲减SOX4后，A549/DDP细胞的耐药性显著降低；敲减SOX4后，A549/DDP细胞中β-catenin和Survivin的mRNA和蛋白表达水平显著降低。

结论

SOX4的表达水平影响非小细胞肺癌细胞A549对顺铂的耐药性。

Co-delivery of paclitaxel and anti-survivin siRNA via redox-sensitive oligopeptide liposomes for the synergistic treatment of breast cancer and metastasis

The overexpression of survivin in breast cancer cells is an important factor of paclitaxel (PTX) resistance in breast cancer. To overcome PTX resistance and improve the antitumor effect of PTX, we developed a novel liposome-based nanosystem (PTX/siRNA/SS-L), composed of a redox-sensitive cationic oligopeptide lipid (LHSSG2C₁₄) with a proton sponge effect, natural soybean phosphatidylcholine (SPC), and cholesterol for co-delivery of PTX and anti-survivin siRNA, which could specifically downregulate survivin overexpression. PTX/siRNA/SS-L exhibited high encapsulation efficiency and rapid redox-responsive release of both PTX and siRNA. Moreover, in vitro studies on the 4T1 breast cancer cells revealed that PTX/siRNA/SS-L offered significant advantages over other experimental groups, such as higher cellular uptake, successful endolysosomal escape, reduced survivin expression, the lowest cell viability and wound healing rate, as well as the highest apoptosis rate. In particular, in vivo evaluation of 4T1 tumor-bearing mice showed that PTX/siRNA/SS-L had lower toxicity and induced a synergistic inhibitory effect on tumor growth and pulmonary metastasis. Collectively, the collaboration of anti-survivin siRNA and PTX via redox-sensitive oligopeptide liposomes provides a promising strategy for the treatment of breast cancer and metastasis.

Amphiphilic carbon dots as versatile vectors for nucleic acid and drug delivery

Carbon dot (CD)-based multifunctional delivery systems have shown great potential in both drug/gene delivery and bio-imaging. In this work, we present a strategy to simply construct amphiphilic CDs (ACDs) by conjugating hydrophobic alkyl epoxide to the surface amino groups of PEI 600-derived CDs. ACDs could well dissolve in water or organic solvents and emit bright fluorescence both in solutions and cells. ¹HNMR also suggested that ACDs may form micelle-like structures in water, and their CMC could be determined. Enhanced green fluorescent protein (EGFP) expression and flow cytometry experiments showed that ACDs have higher transfection efficiency than Lipofectamine 2000 in A549 cells. Besides DNA, ACDs could also effectively transfect Sur siRNA toward A549 cells and cause early cell apoptosis. The 3D multicellular spheroids further confirmed their high potential for delivering therapeutic genes into the tumor tissue. On the other hand, ACDs also exhibited good drug loading ability. CLSM experiment results showed that DOX could be effectively internalized by the cell and slowly released from the drug/ACD complex. These results suggest that ACDs may not only serve as versatile delivery vectors with potential for applications in clinical cancer treatment, but also offer an inspiration for the discovery of CD-based gene/drug delivery systems.

siRNA-loaded poly(histidine-arginine)6-modified chitosan nanoparticle with enhanced cell-penetrating and endosomal escape capacities for suppressing breast tumor metastasis

An ideal carrier that delivers small interfering RNA (siRNA) should be designed based on two criteria: cellular-mediated internalization and endosomal escape. Poly(histidine-arginine)₆(H6R6) peptide was introduced into chitosan (CS) to create a new CS derivative for siRNA delivery, 6-polyarginine (R6) as cell-penetrating peptides facilitated nanoparticle cellular internalization has been proved in our previous research, and 6-polyhistidine (H6) mediated the nanoparticle endosome escape resulted in the siRNA rapid releasing into tumor cytoplasm. H6R6-modified CS nanoparticles showed higher transfection efficiency and better endosomal escape capacity compared to ungroomed CS nanoparticle in vitro. Noticeably, H6R6-modified CS nanoparticles effectively inhibited tumor cell growth and metastases in vivo and significantly improved survival ratio. Therefore, we concluded that H6R6-modified CS copolymer can act as an ideal carrier for siRNA delivery and as a promising candidate in breast cancer therapy.

Nanomedicine of synergistic drug combinations for cancer therapy - Strategies and perspectives

Nanomedicine of synergistic drug combinations has shown increasing significance in cancer therapy due to its promise in providing superior therapeutic benefits to the current drug combination therapy used in clinical practice. In this article, we will examine the rationale, principles, and advantages of applying nanocarriers to improve anticancer drug combination therapy, review the use of nanocarriers for delivery of a variety of combinations of different classes of anticancer agents including small molecule drugs and biologics, and discuss the challenges and future perspectives of the nanocarrier-based combination therapy. The goal of this review is to provide better understanding of this increasingly important new paradigm of cancer treatment and key considerations for rational design of nanomedicine of synergistic drug combinations for cancer therapy.

Overexpression of Mcl-1 confers resistance to BRAFV600E inhibitors alone and in combination with MEK1/2 inhibitors in melanoma

Melanoma harboring BRAF mutations frequently develop resistance to BRAF inhibitors, limiting the impact of treatment. Here, we establish a mechanism of resistance and subsequently identified a suitable drug combination to overcome the resistance. Single treatment of BRAF mutant melanoma cell lines with vemurafenib or dabrafenib (BRAF inhibitors) alone or in combination with trametinib (MEK1/2 inhibitor) resulted in overexpression of Mcl-1. Overexpression of Mcl-1 in A375 and SK-MEL-28 by transfection completely blocked BRAF and MEK1/2 inhibitor-mediated inhibition of cell survival and apoptosis. Melanoma cells resistant to BRAF inhibitors showed massive expression of Mcl-1 as compared to respective sensitive cell lines. Silencing of Mcl-1 using siRNA completely sensitized resistant melanoma cells to growth suppression and induction of apoptosis by BRAF inhibitors. In vivo, vemurafenib resistant A375 xenografts implanted in athymic nude mice showed substantial tumor growth inhibition when treated with a combination of vemurafenib and Mcl-1 inhibitor or siRNA. Immunohistochemistry and western blot analyses demonstrated enhanced expression of Mcl-1 and activation of ERK1/2 in vemurafenib-resistant tumors whereas level of Mcl-1 or p-ERK1/2 was diminished in the tumors of mice treated with either of the combination. Biopsied tumors from the patients treated with or resistant to BRAF inhibitors revealed overexpression of Mcl-1. These results suggest that the combination of BRAF inhibitors with Mcl-1 inhibitor may have therapeutic advantage to melanoma patients with acquired resistance to BRAF inhibitors alone or in combination with MEK1/2 inhibitors.

Tackling breast cancer chemoresistance with nano-formulated siRNA

Breast cancer is the leading cancer diagnosed in women and the second leading cause of cancer-related deaths in women. Current limitations to standard chemotherapy in the clinic are extensively researched, including problems arising from repeated treatments with the same drugs. The phenomenon that cancer cells become resistant toward certain chemo drugs is called chemotherapy resistance. In this review, we are focusing on nanoformulation of siRNA for the fight against breast cancer chemoresistance.

Mixed Nanosized Polymeric Micelles as Promoter of Doxorubicin and miRNA-34a Co-Delivery Triggered by Dual Stimuli in Tumor Tissue

Dual stimuli-sensitive mixed polymeric micelles (MM) are developed for co-delivery of the endogenous tumor suppressor miRNA-34a and the chemotherapeutic agent doxorubicin (Dox) into cancer cells. The novelty of the system resides in two stimuli-sensitive prodrugs, a matrix metalloproteinase 2 (MMP2)-sensitive Dox conjugate and a reducing agent (glutathione, GSH)-sensitive miRNA-34a conjugate, self-assembled in a single particle decorated with a polyethylene glycol corona for longevity, and a cell-penetrating peptide (TATp) for enhanced intracellular delivery. The MMP2-sensitivity of the system results in threefold higher cytotoxicity in MMP2-overexpressing HT1080 cells compared to low MMP2-expressing MCF7 cells. Cellular internalization of Dox increases by more than 70% after inclusion of TATp to the formulation. MMP2-sensitive MM also inhibits proliferation and migration of HT1080 cells. Moreover, GSH-sensitive MM allows for an efficient downregulation of Bcl2, survivin, and notch1 (65%, 55%, and 46%, respectively) in HT1080 cells. Combination of both conjugates in dual sensitive MM reduces HT1080 cell viability to 40% and expression of Bcl2 and survivin. Finally, 50% cell death is observed in 3D models of tumor mass. The results confirm the potential of the MM to codeliver miRNA-34a and doxorubicin triggered by dual stimuli inherent of tumor tissues.

Oligonucleotide conjugates - Candidates for gene silencing therapeutics

The potential therapeutic and diagnostic applications of oligonucleotides (ONs) have attracted great attention in recent years. The capability of ONs to selectively inhibit target genes through antisense and RNA interference mechanisms, without causing un-intended sideeffects has led them to be investigated for various biomedical applications, especially for the treatment of viral diseases and cancer. In recent years, many researchers have focused on enhancing the stability and target specificity of ONs by encapsulating/complexing them with polymers or lipid chains to formulate nanoparticles/nanocomplexes/micelles. Also, chemical modification of nucleic acids has emerged as an alternative to impart stability to ONs against nucleases and other degrading enzymes and proteins found in blood. In addition to chemically modifying the nucleic acids directly, another strategy that has emerged, involves conjugating polymers/peptide/aptamers/antibodies/proteins, preferably to the sense strand (3'end) of siRNAs. Conjugation to the siRNA not only enhances the stability and targeting specificity of the siRNA, but also allows for the development of self-administering siRNA formulations, with a much smaller size than what is usually observed for nanoparticle (∼200nm). This review concentrates mainly on approaches and studies involving ON-conjugates for biomedical applications.

Lipid Nanovectors to Deliver RNA Oligonucleotides in Cancer

The growing knowledge on the mechanisms of gene silencing and gene regulation by non-coding RNAs (ncRNA), mainly small interfering RNA (siRNA) and microRNA (miRNA), is providing a significant boost to the development of new therapeutic strategies for the treatment of cancer. However, the design of RNA-based therapeutics is hampered by biopharmaceutical issues, thus requiring the use of suitable delivery strategies. In this regards, lipid nanovectors have been successfully investigated to deliver RNA in different forms of cancer. Compared to other biomaterials, lipids offer advantages such as biocompatibility, biodegradability, easy production, low cost, limited toxicity and immunogenicity. The possibility to formulate these materials in the form of nanovectors allows overcoming biopharmaceutical issues associated to the therapeutic use of RNA, with the possibility to target tumors. This review takes stock of the main lipid nanovectors proposed to deliver ncRNA. For each considered delivery strategy, the rational design and the most meaningful in vitro and in vivo results are reported and discussed.