Co-delivery of paclitaxel and tetrandrine via iRGD peptide conjugated lipid-polymer hybrid nanoparticles overcome multidrug resistance in cancer cells

Polymer lipid hybrid nanoparticles for phytochemical delivery: challenges, progress, and future prospects

Phytochemicals, naturally occurring compounds in plants, possess a wide range of therapeutic properties, including antioxidant, anti-inflammatory, anticancer, and antimicrobial activities. However, their clinical application is often hindered by poor water solubility, low bioavailability, rapid metabolism, and instability under physiological conditions. Polymer lipid hybrid nanoparticles (PLHNPs) have emerged as a novel delivery system that combines the advantages of both polymeric and lipid-based nanoparticles to overcome these challenges. This review explores the potential of PLHNPs to enhance the delivery and efficacy of phytochemicals for biomedical applications. We discuss the obstacles in the conventional delivery of phytochemicals, the fundamental architecture of PLHNPs, and the types of PLHNPs, highlighting their ability to improve encapsulation efficiency, stability, and controlled release of the encapsulated phytochemicals. In addition, the surface modification strategies to improve overall therapeutic efficacy by site-specific delivery of encapsulated phytochemicals are also discussed. Furthermore, we extensively discuss the preclinical studies on phytochemical encapsulated PLHNPs for the management of different diseases. Additionally, we explore the challenges ahead and prospects of PLHNPs regarding their widespread use in clinical settings. Overall, PLHNPs hold strong potential for the effective delivery of phytochemicals for biomedical applications. As per the findings from pre-clinical studies, this may offer a promising strategy for managing various diseases.

Medicinal plants as a potential resource for the discovery of novel structures towards cancer drug resistance treatment

Despite extensive research in chemotherapy, global cancer concerns persist, exacerbated by the challenge of drug resistance, which imposes economic and medical burdens. Natural compounds, particularly secondary metabolites from medicinal plants, present promising avenues for overcoming cancer drug resistance due to their diverse structures and essential pharmacological effects. This review provides a comprehensive exploration of cancer cell resistance mechanisms and target actions for reversing resistance and highlights the in vitro and in vivo efficacy of noteworthy alkaloids, flavonoids, and other compounds, emphasizing their potential as therapeutic agents. The molecular properties supporting ligand interactions are thoroughly examined, providing a robust theoretical foundation. The review concludes by discussing methods including quantitative structure-activity relationships and molecular docking, offering insights into screening potential candidates. Current trends in clinical treatment, contributing to a holistic understanding of the multifaceted approaches to address cancer drug resistance are also outlined.

Advances in nano-preparations for improving tetrandrine solubility and bioavailability

Tetrandrine (TET) is a natural bis-benzylisoquinoline alkaloid isolated from Stephania species with a wide range of biological and pharmacologic activities; it mainly serves as an anti-inflammatory agent or antitumor adjuvant in clinical applications. However, limitations such as prominent hydrophobicity, severe off-target toxicity, and low absorption result in suboptimal therapeutic outcomes preventing its widespread adoption. Nanoparticles have proven to be efficient devices for targeted drug delivery since drug-carrying nanoparticles can be passively transported to the tumor site by the enhanced permeability and retention (EPR) effects, thus securing a niche in cancer therapies. Great progress has been made in nanocarrier construction for TET delivery due to their outstanding advantages such as increased water-solubility, improved biodistribution and blood circulation, reduced off-target irritation, and combinational therapy. Herein, we systematically reviewed the latest advancements in TET-loaded nanoparticles and their respective features with the expectation of providing perspective and guidelines for future research and potential applications of TET.

Advances in active targeting of ligand-directed polymeric nanomicelles via exploiting overexpressed cellular receptors for precise nanomedicine

Many of the utilized drugs which already exist in the pharmaceutical sector are hydrophobic in nature. These drugs are characterized by being poorly absorbed and difficult to formulate in aqueous environments with low bioavailability, which could result in consuming high and frequent doses in order to fulfil the required therapeutic effect. As a result, there is a decisive demand to find modern alternatives to overcome all these drawbacks. Self-assembling polymeric nanomicelles (PMs) with their unique structure appear to be a fascinating choice as a pharmaceutical carrier system for improving the solubility & bioavailability of many drugs. PMs as drug carriers have many advantages including suitable size, high stability, prolonged circulation time, elevated cargo capacity and controlled therapeutic release. Otherwise, the pathological features of some diseased cells, like cancer, allow PMs with particle size <200 nm to be passively uptaken via enhanced permeability and retention phenomenon (EPR). However, the passive targeting approach was proven to be insufficient in many cases. Consequently, the therapeutic efficiency of these PMs can be further reinforced by enhancing their cellular internalization via incorporating targeting ligands. These targeting ligands can enhance the assemblage of loaded cargos in the intended tissues via receptor-mediated endocytosis through exploiting receptors robustly expressed on the exterior of the intended tissue while minimizing their toxic effects. In this review, the up-to-date approaches of harnessing active targeting ligands to exploit certain overexpressed receptors will be summarized concerning the functionalization of the exterior of PMs for ameliorating their targeting potential in the scope of nanomedicine.

Cancer therapy with iRGD as a tumor-penetrating peptide

One of the primary threats in tumor treatment revolves around the limited ability to penetrate tumor sites, leading to reduced therapeutic effectiveness, which remains a critical concern. Recently gaining importance are novel peptides, namely CRGDK/RGPD/EC (iRGD), that possess enhanced tumor-penetrating and inhibitory properties. These peptides specifically target and penetrate tumors by binding to αvβ integrins, namely αvβ3 and αvβ5, as well as NRP-1 receptors. Remarkably abundant on both the vasculature and tumor cell surfaces, these peptides show promising potential for improving tumor treatment outcomes. As a result, iRGD penetrated deep into the tumor tissues with biological products, contrast agents (imaging agents), antitumor drugs, and immune modulators after co-injecting them with peptides or chemically linked to peptides. The synthesis of iRGD peptides is a relatively straightforward process compared to the synthesis of other traditional peptides, and they significantly improved tumor tissue penetration inhibiting tumor metastasis effectively. Recent studies demonstrate the effectiveness of iRGD-driven dual-targeting chemotherapeutics on cancer cells, and the nanocarriers were modified with iRGD, serving as a favorable delivery strategy of payloads for deeper tumor regions. This review aims to provide an overview to emphasize the recent advancements and advantages of iRGD in treating and imaging various cancers.

Recent Advancements and Strategies for Overcoming the Blood-Brain Barrier Using Albumin-Based Drug Delivery Systems to Treat Brain Cancer, with a Focus on Glioblastoma

Glioblastoma multiforme (GBM) is a highly aggressive malignant tumor, and the most prevalent primary malignant tumor affecting the brain and central nervous system. Recent research indicates that the genetic profile of GBM makes it resistant to drugs and radiation. However, the main obstacle in treating GBM is transporting drugs through the blood-brain barrier (BBB). Albumin is a versatile biomaterial for the synthesis of nanoparticles. The efficiency of albumin-based delivery systems is determined by their ability to improve tumor targeting and accumulation. In this review, we will discuss the prevalence of human glioblastoma and the currently adopted treatment, as well as the structure and some essential functions of the BBB, to transport drugs through this barrier. We will also mention some aspects related to the blood-tumor brain barrier (BTBB) that lead to poor treatment efficacy. The properties and structure of serum albumin were highlighted, such as its role in targeting brain tumors, as well as the progress made until now regarding the techniques for obtaining albumin nanoparticles and their functionalization, in order to overcome the BBB and treat cancer, especially human glioblastoma. The albumin drug delivery nanosystems mentioned in this paper have improved properties and can overcome the BBB to target brain tumors.

Active Ingredients from Chinese Medicine for Combination Cancer Therapy

Combination therapy against cancer has gained increasing attention because it can help to target multiple pathways to tackle oncologic progression and improve the limited antitumor effect of single-agent therapy. Chinese medicine has been studied extensively in cancer therapy and proven to be efficacious in many cases due to its wide spectrum of anticancer activities. In this review, we aim to summarize the recent progress of active ingredients from Chinese medicine (AIFCM) in combination with various cancer therapeutic modalities, including chemotherapy, gene therapy, radiotherapy, phototherapy and immunotherapy. In addition to highlighting the potential contribution of AIFCM in combination cancer therapy, we also elucidate the underlying mechanisms behind their synergistic effect and improved anticancer efficacy, thereby encouraging the inclusion of these AIFCM as part of effective armamentarium in fighting intractable cancers. Finally, we present the challenges and future perspectives of AIFCM combination therapy as a feasible and promising strategy for the optimization of cancer treatment and better clinical outcomes.

Controllable release of self-assembled reduction-sensitive paclitaxel dimer prodrug and tetrandrine nanoparticles promotes synergistic therapy against multidrug-resistant cancer

BACKGROUND

Multidrug resistance (MDR) is the main reason for chemotherapy failure. Nanocarriers combined delivery of anti-cancer drugs and MDR inhibitors is an effective strategy to avoid MDR and improve the anti-cancer activity of drugs.

METHODS

Two paclitaxel (PTX) molecules are linked by disulfide bonds into PTX₂. Then, the PTX₂ and tetrandrine (TET) are coated together by mPEG-PLGA self-assembled NPs for combinational treatment. Microstructure, physiological stability, and cytotoxicity are characterized for the co-loaded NPs.

RESULTS

The NPs exhibit excellent suitability and blood safety for intravenous injection, specifically responsive to pH 6-7, and promptly initiate chemical degradation. Ex vivo fluorescence microscopy image studies indicate that co-loaded NPs increase drug penetration into cancer cells compared with free drugs. MTT assay demonstrates that co-loaded NPs have higher cytotoxicity against HeLa and the flow cytometric analysis shows that co-loaded NPs trigger more apoptosis than the free drugs. Reactive oxygen species (ROS) assay indicates that the drug-loaded NPs generated higher levels of ROS to accelerate apoptosis in HeLa cells.

CONCLUSIONS

TET can get desirable effects of inhibiting the MDR in advance by binding with the active site on P-gp, then the disulfide bond of PTX₂ is broken by glutathione (GSH) in cancer cells and decomposed into PTX to inhibit cancer cell proliferation.

GENERAL SIGNIFICANCE

Our studies indicate that the co-loaded NPs can potentially overcome the MDR of conventional chemotherapeutic agents.

Stimuli-responsive drug delivery systems triggered by intracellular or subcellular microenvironments

Drug delivery systems (DDS) triggered by local microenvironment represents the state-of-art of nanomedicine design, where the triggering hallmarks at intracellular and subcellular levels could be employed to exquisitely recognize the diseased sites, reduce side effects, and expand the therapeutic window by precisely tailoring the drug-release kinetics. Though with impressive progress, the DDS design functioning at microcosmic levels is fully challenging and underexploited. Here, we provide an overview describing the recent advances on stimuli-responsive DDSs triggered by intracellular or subcellular microenvironments. Instead of focusing on the targeting strategies as listed in previous reviews, we herein mainly highlight the concept, design, preparation and applications of stimuli-responsive systems in intracellular models. Hopefully, this review could give useful hints in developing nanoplatforms proceeding at a cellular level.

Engineering Transferrin-Decorated Pullulan-Based Prodrug Nanoparticles for Redox Responsive Paclitaxel Delivery to Metastatic Lung Cancer Cells

Paclitaxel (PTX) remains a cornerstone in the treatment of locally advanced and metastatic lung cancer. To improve its therapeutic indices against lung cancer, novel redox-sensitive pullulan/PTX-based prodrug NPs (PULL-SS-PTX NPs) were accomplished, which were further surface-decorated with transferrin (TF), a cancer cell-targeting ligand, to afford TF-PULL-SS-PTX NPs. These prodrug NPs (drug content, >37% and average size, 134-163 nm) rapidly dismantled their self-assembled architecture upon exposure to simulated reducing conditions, causing a triggered drug release as compared to the control scaffold (PULL-CC-PTX NPs). These scaffolds also evidenced outstanding colloidal stability, cellular uptake efficiency, and discriminating cytotoxicity between the cancer and healthy cells. Intravenously delivered redox-sensitive NPs exhibited improved tumor-suppressing properties as compared to the control nanovesicles (PULL-CC-PTX NPs) in a B16-F10 melanoma lung metastasis mice model. The targeting efficiency and associated augmented anticancer potentials of TF-PULL-SS-PTX NPs relative to TF-free redox-responsive NPs and Taxol intravenous injection were also established on the transferrin receptor (TFR) overexpressed Lewis lung carcinoma (LLC-luc) cell-bearing mice model. Moreover, the TF-functionalized scaffold displayed a reduced systemic toxicity compared to that of Taxol intravenous injection. Overall, the proposed TF-decorated prodrug NPs could be a promising nanomedicine for intracellular PTX delivery against metastatic lung cancer.

Nano-drug co-delivery system of natural active ingredients and chemotherapy drugs for cancer treatment: a review

Chemotherapy drugs have been used for a long time in the treatment of cancer, but serious side effects are caused by the inability of the drug to be solely delivered to the tumor when treating cancer with chemotherapy. Natural products have attracted more and more attention due to the antitumor effect in multiple ways, abundant resources and less side effects. Therefore, the combination of natural active ingredients and chemotherapy drugs may be an effective antitumor strategy, which can inhibit the growth of tumor and multidrug resistance, reduce side effects of chemotherapy drugs. Nano-drug co-delivery system (NDCDS) can play an important role in the combination of natural active ingredients and chemotherapy drugs. This review provides a comprehensive summary of the research status and application prospect of nano-delivery strategies for the combination of natural active ingredients and chemotherapy drugs, aiming to provide a basis for the development of anti-tumor drugs.

A nanodiamond chemotherapeutic folate receptor-targeting prodrug with triggerable drug release

Cancer chemotherapy is often accompanied by severe off-target effects that both damage quality of life and can decrease therapeutic compliance. This could be minimized through selective delivery of cytotoxic agents directly to the cancer cells. This would decrease the drug dose, consequently minimizing side effects and cost. With this goal in mind, a dual-gated folate-functionalized nanodiamond drug delivery system (NPFSSD) for doxorubicin with activatable fluorescence and cytotoxicity has been prepared. Both the cytotoxic activity and the fluorescence of doxorubicin (DOX) are quenched when it is covalently immobilized on the nanodiamond. The NPFSSD is preferentially uptaken by cancer cells overexpressing the folate receptor. Then, once inside a cell, the drug is preferentially released within tumor cells due to their high levels of endogenous of glutathione, required for releasing DOX through cleavage of a disulfide linker. Interestingly, once free DOX is loaded onto the nanodiamond, it can also evade resistance mechanisms that use protein pumps to remove drugs from the cytoplasm. This nanodrug, used in an in vivo model with local injection of drugs, effectively inhibits tumor growth with fewer side effects than direct injection of free DOX, providing a potentially powerful platform to improve therapeutic outcomes.

Overcoming multidrug resistance through targeting ABC transporters: lessons for drug discovery

INTRODUCTION

The argument around cancer therapy is an old one. Using chemotherapeutic drugs, as one of the most effective strategies in treatment of malignancies, is restricted by various issues that progress during therapy and avoid achieving clinical endpoints. Multidrug resistance (MDR), frequently mediated by ATP-binding cassette (ABC) transporters, is one of the most recognized obstacles in the success of pharmacological anticancer approaches. These transporters efflux diverse drugs to extracellular environment, causing MDR and responsiveness of tumor cells to chemotherapy diminishes.

AREAS COVERED

Several strategies have been used to overcome MDR phenomenon. Succession in this field requires complete knowledge about features and mechanism of ABC transporters. In this review, conventional synthetic and natural inhibitors are discussed first and then novel approaches including RNA, monoclonal antibodies, nanobiotechnology, and structural modification techniques are represented.

EXPERT OPINION

With increasing frequency of MDR in cancer cells, it is essential to develop new drugs to inhibit MDR. Using knowledge acquired about ABC transporter's structure, rational design of inhibitors is possible. Also, some herbal products have shown to be potential lead compounds in drug discovery for reversal of MDR.

Progress on structural modification of Tetrandrine with wide range of pharmacological activities

Tetrandrine (Tet), derived from the traditional Chinese herb Fangji, is a class of natural alkaloids with the structure of bisbenzylisoquinoline, which has a wide range of physiological activities and significant pharmacfological effects. However, studies and clinical applications have revealed a series of drawbacks such as its poor water solubility, low bioavailability, and the fact that it can be toxic to humans. The results of many researchers have confirmed that chemical structural modifications and nanocarrier delivery can address the limited application of Tet and improve its efficacy. In this paper, we summarize the anti-tumor efficacy and mechanism of action, anti-inflammatory efficacy and mechanism of action, and clinical applications of Tet, and describe the progress of Tet based on chemical structure modification and nanocarrier delivery, aiming to explore more diverse structures to improve the pharmacological activity of Tet and provide ideas to meet clinical needs.

Peptide-Based Bioconjugates and Therapeutics for Targeted Anticancer Therapy

With rapidly growing knowledge in bioinformatics related to peptides and proteins, amino acid-based drug-design strategies have recently gained importance in pharmaceutics. In the past, peptide-based biomedicines were not widely used due to the associated severe physiological problems, such as low selectivity and rapid degradation in biological systems. However, various interesting peptide-based therapeutics combined with drug-delivery systems have recently emerged. Many of these candidates have been developed for anticancer therapy that requires precisely targeted effects and low toxicity. These research trends have become more diverse and complex owing to nanomedicine and antibody–drug conjugates (ADC), showing excellent therapeutic efficacy. Various newly developed peptide–drug conjugates (PDC), peptide-based nanoparticles, and prodrugs could represent a promising therapeutic strategy for patients. In this review, we provide valuable insights into rational drug design and development for future pharmaceutics.

Ultra-small lipid carriers with adjustable release profiles for synergistic treatment of drug-resistant ovarian cancer

Multidrug resistance has dramatically compromised the effectiveness of paclitaxel (PTX). The combined application of PTX and tetrandrine (TET) is a promising avenue in drug-resistant cancer therapy. However, poor drug release and limited intracellular drug accumulation greatly impede this combinational antitumor therapy. To address this problem, we successfully developed a tunable controlled release lipid platform (PT@usNLC) for coordinated drug delivery. The drug release rate of PT@usNLC can be tuned by varying the lipid ratio, which has potential to maximize the therapeutic effects of combined drugs. The TET release rate from PT@usNLC was faster than PTX, which could restore the sensitivity of tumor cells to PTX and exert a synergistic antitumor effect. The appropriate size of PT@usNLC could effectively increase the intracellular drug accumulation. Bothin vitroandin vivostudies revealed that PT@usNLC significantly enhanced the therapeutic effect compared to conventional therapies. This study provides a new strategy for resistant ovarian cancer therapy.

Vitamin-H Channeled Self-Therapeutic P-gp Inhibitor Curcumin-Derived Nanomicelles for Targeting the Tumor Milieu by pH- and Enzyme-Triggered Hierarchical Disassembly

An effective nanocarrier-mediated drug delivery to cancer cells primarily faces limitations like the presence of successive drug delivery barriers, insufficient circulation time, drug leakage, and decreased tumor penetration capacity. With the aim of addressing this paradox, a self-therapeutic, curcumin-derived copolymer was synthesized by conjugation with PEGylated biotin via enzyme- and acid-labile ester and acetal linkages. This copolymer is a prodrug of curcumin and self-assembles into ∼150-200 nm-sized nanomicelles; it is capable of encapsulating doxorubicin (DOX) and hence can be designated as self-therapeutic. pH- and enzyme-responsive linkages in the polymer skeleton assist in its hierarchical disassembly only in the tumor microenvironment. Further, the conjugation of biotin and poly(ethylene glycol) (PEG) imparts features of tumor specificity and improved circulation times to the nanocarrier. The dynamic light scattering (DLS) analysis supports this claim and demonstrates rapid swelling and disruption of micelles under acidic pH. UV-vis spectroscopy provided evidence of an accelerated acetal degradation at pH 4.0 and 5.0. The in vitro release studies revealed a controlled release of DOX under acidic conditions and curcumin release in response to the enzyme. The value of the combination index calculated on HepG2 cells was found to be <1, and hence, the drug pair curcumin and DOX acts synergistically for tumor regression. To prove the efficiency of acid-labile linkages and the prodrug strategy for effective cancer therapy, curcumin-derived polymers devoid of sensitive linkages were also prepared. The prodrug stimuli-responsive nanomicelles showed enhanced cell cytotoxicity and tumor penetration capability on HepG2 cells as well as drug-resistant MCF-7 cell lines and no effect on normal NIH/3T3 fibroblasts as compared to the nonresponsive micelles. The results were also supported by in vivo evidence on a hepatocellular carcinoma (HCC)-induced nude mice model. An evident decrease in MMP-2, MMP-9, and α-fetoprotein (AFP), the biomarkers specific to tumor progression, was observed along with metastasis upon treatment with the drug-loaded dual-responsive nanomicelles. These observations corroborated with the SGOT and SGPT data as well as the histoarchitecture of the liver tissue in mice.

Emerging Nano-Based Strategies Against Drug Resistance in Tumor Chemotherapy

Drug resistance is the most significant causes of cancer chemotherapy failure. Various mechanisms of drug resistance include tumor heterogeneity, tumor microenvironment, changes at cellular levels, genetic factors, and other mechanisms. In recent years, more attention has been paid to tumor resistance mechanisms and countermeasures. Nanomedicine is an emerging treatment platform, focusing on alternative drug delivery and improved therapeutic effectiveness while reducing side effects on normal tissues. Here, we reviewed the principal forms of drug resistance and the new possibilities that nanomaterials offer for overcoming these therapeutic barriers. Novel nanomaterials based on tumor types are an excellent modality to equalize drug resistance that enables gain more rational and flexible drug selectivity for individual patient treatment. With the emergence of advanced designs and alternative drug delivery strategies with different nanomaterials, overcome of multidrug resistance shows promising and opens new horizons for cancer therapy. This review discussed different mechanisms of drug resistance and recent advances in nanotechnology-based therapeutic strategies to improve the sensitivity and effectiveness of chemotherapeutic drugs, aiming to show the advantages of nanomaterials in overcoming of drug resistance for tumor chemotherapy, which could accelerate the development of personalized medicine.

Emerging nanotechnology based combination therapies of taxanes for multiple drug-resistant cancers

'One drug- one target' to 'multiple drug- multiple targets' paradigm shifted to produce combination therapies, have found great outcomes to overcome multiple drug resistance (MDR). MDR is a significant barrier to the delivery of taxane-based anticancer medicines such as docetaxel, paclitaxel, and cabazitaxel. Due to MDR induced by drug efflux transporters, clinical application of these medications is impeded. To date, nanoformulations such as liposomes, micelles, polymeric nanoparticles, and gold nanoparticles have been investigated to deliver taxanes alone and in combination to reverse drug resistance. Despite the fact that various groups have already looked into taxane nano formulations in the literature, there isn't much in the way of polypharmacology and advanced nanoformulations with a focus on MDR. In this overview, we briefly covered the insights regarding MDR, difficulties related to current pharmaceutical products of taxanes, combination therapies of taxanes to combat MDR, all of which can be used to delve into cancer treatment.

Traditional herbal medicine and nanomedicine: Converging disciplines to improve therapeutic efficacy and human health

Traditional herbal medicine (THM), an ancient science, is a gift from nature. For thousands of years, it has helped humans fight diseases and protect life, health, and reproduction. Nanomedicine, a newer discipline has evolved from exploitation of the unique nanoscale morphology and is widely used in diagnosis, imaging, drug delivery, and other biomedical fields. Although THM and nanomedicine differ greatly in time span and discipline dimensions, they are closely related and are even evolving toward integration and convergence. This review begins with the history and latest research progress of THM and nanomedicine, expounding their respective developmental trajectory. It then discusses the overlapping connectivity and relevance of the two fields, including nanoaggregates generated in herbal medicine decoctions, the application of nanotechnology in the delivery and treatment of natural active ingredients, and the influence of physiological regulatory capability of THM on the in vivo fate of nanoparticles. Finally, future development trends, challenges, and research directions are discussed.

Supramolecular peptide nano-assemblies for cancer diagnosis and therapy: from molecular design to material synthesis and function-specific applications

Peptide molecule has high bioactivity, good biocompatibility, and excellent biodegradability. In addition, it has adjustable amino acid structure and sequence, which can be flexible designed and tailored to form supramolecular nano-assemblies with specific biomimicking, recognition, and targeting properties via molecular self-assembly. These unique properties of peptide nano-assemblies made it possible for utilizing them for biomedical and tissue engineering applications. In this review, we summarize recent progress on the motif design, self-assembly synthesis, and functional tailoring of peptide nano-assemblies for both cancer diagnosis and therapy. For this aim, firstly we demonstrate the methodologies on the synthesis of various functional pure and hybrid peptide nano-assemblies, by which the structural and functional tailoring of peptide nano-assemblies are introduced and discussed in detail. Secondly, we present the applications of peptide nano-assemblies for cancer diagnosis applications, including optical and magnetic imaging as well as biosensing of cancer cells. Thirdly, the design of peptide nano-assemblies for enzyme-mediated killing, chemo-therapy, photothermal therapy, and multi-therapy of cancer cells are introduced. Finally, the challenges and perspectives in this promising topic are discussed. This work will be useful for readers to understand the methodologies on peptide design and functional tailoring for highly effective, specific, and targeted diagnosis and therapy of cancers, and at the same time it will promote the development of cancer diagnosis and therapy by linking those knowledges in biological science, nanotechnology, biomedicine, tissue engineering, and analytical science.

Nanoplatform-based natural products co-delivery system to surmount cancer multidrug-resistant

The emergence of multidrug resistance (MDR) in malignant tumors is the primary reason for invalid chemotherapy. Antitumor drugs are often adversely affected by the MDR of tumor cells. Treatments using conventional drugs, which have specific drug targets, hardly regulate the complex signaling pathway of MDR cells because of the complex formation mechanism of MDR. However, natural products have positive advantages, such as high efficiency, low toxicity, and ability to target multiple mechanism pathways associated with MDR. Natural products, as MDR reversal agents, synergize with chemotherapeutics and enhance the sensitivity of tumor cells to chemotherapeutics, and the co-delivery of natural products and antitumor drugs with nanocarriers maximizes the synergistic effects against MDR in tumor cells. This review summarizes the molecular mechanisms of MDR, the advantages of natural products combined with chemotherapeutics in offsetting complicated MDR mechanisms, and the types and mechanisms of natural products that are potential MDR reversal modulators. Meanwhile, aiming at the low bioavailability of cocktail combined natural products and chemotherapeutic in vivo, the advantages of nanoplatform-based co-delivery system and recent research developments are illustrated on the basis of our previous research. Finally, prospective horizons are analyzed, which are expected to considerably improve the nano-co-delivery of natural products and chemotherapeutic systems for MDR reversal in cancer.

Antimicrobial Activities of LL-37 Fragment Mutant-Poly (Lactic-Co-Glycolic) Acid Conjugate against Staphylococcus aureus, Escherichia coli, and Candida albicans

Various peptides and their derivatives have been reported to exhibit antimicrobial activities. Although these activities have been examined against microorganisms, novel methods have recently emerged for conjugation of the biomaterials to improve their activities. Here, we prepared CKR12-PLGA, in which CKR12 (a mutated fragment of human cathelicidin peptide, LL-37) was conjugated with poly (lactic-co-glycolic) acid (PLGA), and compared the antimicrobial and antifungal activities of the conjugated peptide with those of FK13 (a small fragment of LL-37) and CKR12 alone. The prepared CKR12-PLGA was characterized by dynamic light scattering and measurement of the zeta potential, critical micellar concentration, and antimicrobial activities of the fragments and conjugate. Although CKR12 showed higher antibacterial activities than FK13 against Staphylococcus aureus and Escherichia coli, the antifungal activity of CKR12 was lower than that of FK13. CKR12-PLGA showed higher antibacterial activities against S. aureus and E. coli and higher antifungal activity against Candida albicans compared to those of FK13. Additionally, CKR12-PLGA showed no hemolytic activity in erythrocytes, and scanning and transmission electron microscopy suggested that CKR12-PLGA killed and disrupted the surface structure of microbial cells. Conjugation of antimicrobial peptide fragment analogues was a successful approach for obtaining increased microbial activity with minimized cytotoxicity.

The reversal of chemotherapy-induced multidrug resistance by nanomedicine for cancer therapy

Multidrug resistance (MDR) of cancer is a persistent problem in chemotherapy. Scientists have considered the overexpressed efflux transporters responsible for MDR and chemotherapy failure. MDR extremely limits the therapeutic effect of chemotherapy in cancer treatment. Many strategies have been applied to solve this problem. Multifunctional nanoparticles may be one of the most promising approaches to reverse MDR of tumor. These nanoparticles can keep stability in the blood circulation and selectively accumulated in the tumor microenvironment (TME) either by passive or active targeting. The stimuli-sensitive or organelle-targeting nanoparticles can release the drug at the targeted-site without exposure to normal tissues. In order to better understand reversal of MDR, three main strategies are concluded in this review. First strategy is the synergistic effect of chemotherapeutic drugs and ABC transporter inhibitors. Through directly inhibiting overexpressed ABC transporters, chemotherapeutic drugs can enter into resistant cells without being efflux. Second strategy is based on nanoparticles circumventing over-expressed efflux transporters and directly targeting resistance-related organelles. Third approach is the combination of multiple therapy modes overcoming cancer resistance. At last, numerous researches demonstrated cancer stem-like cells (CSCs) had a deep relation with drug resistance. Here, we discuss two different drug delivery approaches of nanomedicine based on CSC therapy.

Polymeric Nanoparticle Delivery of Combination Therapy with Synergistic Effects in Ovarian Cancer

Treatment of ovarian cancer is challenging due to late stage diagnosis, acquired drug resistance mechanisms, and systemic toxicity of chemotherapeutic agents. Combination chemotherapy has the potential to enhance treatment efficacy by activation of multiple downstream pathways to overcome drug resistance and reducing required dosages. Sequence of delivery and the dosing schedule can further enhance treatment efficacy. Formulation of drug combinations into nanoparticles can further enhance treatment efficacy. Due to their versatility, polymer-based nanoparticles are an especially promising tool for clinical translation of combination therapies with tunable dosing schedules. We review polymer nanoparticle (e.g., micelles, dendrimers, and lipid nanoparticles) carriers of drug combinations formulated to treat ovarian cancer. In particular, the focus on this review is combinations of platinum and taxane agents (commonly used first line treatments for ovarian cancer) combined with other small molecule therapeutic agents. In vitro and in vivo drug potency are discussed with a focus on quantifiable synergistic effects. The effect of drug sequence and dosing schedule is examined. Computational approaches as a tool to predict synergistic drug combinations and dosing schedules as a tool for future nanoparticle design are also briefly discussed.

Therapeutic strategies to overcome taxane resistance in cancer

One of the primary causes of attenuated or loss of efficacy of cancer chemotherapy is the emergence of multidrug resistance (MDR). Numerous studies have been published regarding potential approaches to reverse resistance to taxanes, including paclitaxel (PTX) and docetaxel, which represent one of the most important classes of anticancer drugs. Since 1984, following the FDA approval of paclitaxel for the treatment of advanced ovarian carcinoma, taxanes have been extensively used as drugs that target tumor microtubules. Taxanes, have been shown to affect an array of oncogenic signaling pathways and have potent cytotoxic efficacy. However, the clinical success of these drugs has been restricted by the emergence of cancer cell resistance, primarily caused by the overexpression of MDR efflux transporters or by microtubule alterations. In vitro and in vivo studies indicate that the mechanisms underlying the resistance to PTX and docetaxel are primarily due to alterations in α-tubulin and β-tubulin. Moreover, resistance to PTX and docetaxel results from: 1) alterations in microtubule-protein interactions, including microtubule-associated protein 4, stathmin, centriole, cilia, spindle-associated protein, and kinesins; 2) alterations in the expression and activity of multidrug efflux transporters of the ABC superfamily including P-glycoprotein (P-gp/ABCB1); 3) overexpression of anti-apoptotic proteins or inhibition of apoptotic proteins and tumor-suppressor proteins, as well as 4) modulation of signal transduction pathways associated with the activity of several cytokines, chemokines and transcription factors. In this review, we discuss the abovementioned molecular mechanisms and their role in mediating cancer chemoresistance to PTX and docetaxel. We provide a detailed analysis of both in vitro and in vivo experimental data and describe the application of these findings to therapeutic practice. The current review also discusses the efficacy of different pharmacological modulations to achieve reversal of PTX resistance. The therapeutic roles of several novel compounds, as well as herbal formulations, are also discussed. Among them, many structural derivatives had efficacy against the MDR phenotype by either suppressing MDR or increasing the cytotoxic efficacy compared to the parental drugs, or both. Natural products functioning as MDR chemosensitizers offer novel treatment strategies in patients with chemoresistant cancers by attenuating MDR and increasing chemotherapy efficacy. We broadly discuss the roles of inhibitors of P-gp and other efflux pumps, in the reversal of PTX and docetaxel resistance in cancer cells and the significance of using a nanomedicine delivery system in this context. Thus, a better understanding of the molecular mechanisms mediating the reversal of drug resistance, combined with drug efficacy and the application of target-based inhibition or specific drug delivery, could signal a new era in modern medicine that would limit the pathological consequences of MDR in cancer patients.

Redox-sensitive carrier-free nanoparticles self-assembled by disulfide-linked paclitaxel-tetramethylpyrazine conjugate for combination cancer chemotherapy

Rationale: Combinations of two or more therapeutic agents targeting different signaling pathways involved in tumor progression can have synergistic anticancer effects. However, combination chemotherapies are greatly limited by the different pharmacokinetics, tumor targeting, and cellular uptake capacities of the combined drugs. We have previously demonstrated the potential synergistic efficacy of paclitaxel (PTX) and the natural anti-angiogenic agent tetramethylpyrazine (TMP) for suppressing ovarian carcinoma growth. An efficient, facile, and smart nanosystem to deliver PTX and TMP simultaneously in vivo is greatly desired.

Methods: We constructed a redox-sensitive nanosystem based on the amphiphilic PTX-ss-TMP conjugate, in which PTX and TMP are linked by a disulfide bond. We characterized the structure of the drug conjugate by ¹H NMR and LC-MS, and then prepared PTX-ss-TMP NPs by a one-step nanoprecipitation method. We investigated the redox sensitivity, tumor-targeting ability, anticancer efficacy, and anti-angiogenesis activity of PTX-ss-TMP NPs in vitro and in vivo.

Results: The amphiphilic PTX-ss-TMP conjugate readily self-assembled into stable nanoparticles in aqueous solution with a low critical association concentration of 1.35 µg/mL, well-defined spherical structure, small particle size (152 nm), high drug loading, redox-responsive drug release, high biocompatibility, and high storage stability. In cancer cells pretreated with GSH-OEt, PTX-ss-TMP NPs exhibited higher cytotoxicity, apoptosis rate, and cell-cycle arrest than monotherapy or combination therapy with free drugs, which was attributed to their improved cellular uptake and rapid intracellular drug release. Additionally, PTX-ss-TMP NPs also had a stronger anti-angiogenesis effect in HUVECs than free drug, which was mediated by VEGFR2-involved downstream signals. Finally, PTX-ss-TMP NPs showed tumor-specific accumulation and excellent antitumor activity in A2780 xenograft mice compared with free drug.

Conclusions: These in vitro and in vivo results provide clear evidence that this redox-responsive carrier-free nanosystem with intrinsic amphiphilicity has great potential for combination cancer chemotherapy.

Celastrol: A Review of Useful Strategies Overcoming its Limitation in Anticancer Application

Celastrol, a natural bioactive ingredient derived from Tripterygium wilfordii Hook F, exhibits significant broad-spectrum anticancer activities for the treatment of a variety of cancers including liver cancer, breast cancer, prostate tumor, multiple myeloma, glioma, etc. However, the poor water stability, low bioavailability, narrow therapeutic window, and undesired side effects greatly limit its clinical application. To address this issue, some strategies were employed to improve the anticancer efficacy and reduce the side-effects of celastrol. The present review comprehensively focuses on the various challenges associated with the anticancer efficiency and drug delivery of celastrol, and the useful approaches including combination therapy, structural derivatives and nano/micro-systems development. The specific advantages for the use of celastrol mediated by these strategies are presented. Moreover, the challenges and future research directions are also discussed. Based on this review, it would provide a reference to develop a natural anticancer compound for cancer treatment.

Systemic brain tumor delivery of synthetic protein nanoparticles for glioblastoma therapy

Glioblastoma (GBM), the most aggressive form of brain cancer, has witnessed very little clinical progress over the last decades, in part, due to the absence of effective drug delivery strategies. Intravenous injection is the least invasive drug delivery route to the brain, but has been severely limited by the blood-brain barrier (BBB). Inspired by the capacity of natural proteins and viral particulates to cross the BBB, we engineered a synthetic protein nanoparticle (SPNP) based on polymerized human serum albumin (HSA) equipped with the cell-penetrating peptide iRGD. SPNPs containing siRNA against Signal Transducer and Activation of Transcription 3 factor (STAT3i) result in in vitro and in vivo downregulation of STAT3, a central hub associated with GBM progression. When combined with the standard of care, ionized radiation, STAT3i SPNPs result in tumor regression and long-term survival in 87.5% of GBM-bearing mice and prime the immune system to develop anti-GBM immunological memory.

Utilization of Polymer-Lipid Hybrid Nanoparticles for Targeted Anti-Cancer Therapy

Cancer represents one of the most dangerous diseases, with 1.8 million deaths worldwide. Despite remarkable advances in conventional therapies, these treatments are not effective to completely eradicate cancer. Nanotechnology offers potential cancer treatment based on formulations of several nanoparticles (NPs). Liposomes and polymeric nanoparticle are the most investigated and effective drug delivery systems (DDS) for cancer treatment. Liposomes represent potential DDS due to their distinct properties, including high-drug entrapment efficacy, biocompatibility, low cost, and scalability. However, their use is restricted by susceptibility to lipid peroxidation, instability, burst release of drugs, and the limited surface modification. Similarly, polymeric nanoparticles show several chemical modifications with polymers, good stability, and controlled release, but their drawbacks for biological applications include limited drug loading, polymer toxicity, and difficulties in scaling up. Therefore, polymeric nanoparticles and liposomes are combined to form polymer-lipid hybrid nanoparticles (PLHNPs), with the positive attributes of both components such as high biocompatibility and stability, improved drug payload, controlled drug release, longer circulation time, and superior in vivo efficacy. In this review, we have focused on the prominent strategies used to develop tumor targeting PLHNPs and discuss their advantages and unique properties contributing to an ideal DDS.

Dual variable of drug loaded micelles in both particle and electrical charge on gastric cancer treatment

Gastric cancer is a malignant tumour characterised by the uncontrolled cell growth. The incidence and mortality of gastric cancer remain high for the invasion and metastasis. We are urgently seeking a risk-free and effective treatment strategy for gastric cancer. In this study, paclitaxel and tetrandrine were encapsulated in the inner core of micelles, and DSPE-PEG₂₀₀₀-CPP and HA were modified on the micellar surface. HA/CPP modified paclitaxel plus tetrandrine micelles had a suitable particle size (90 nm) for permeating tumour tissue. The zeta potential of the targeting micelles was 8.37 mV after hydrolysis by HAase solution. Results of in vitro experiments indicated that HA/CPP modified paclitaxel plus tetrandrine micelles + HAase could enhance the intracellular uptake, inhibit the formation of neovascularization, block the process of EMT and destroy the invasion and metastasis. In vivo assays indicated that HA/CPP modified paclitaxel plus tetrandrine micelles could be selectively accumulated into tumour sites and exhibited the strong antitumor activity with negligible toxicity. These results suggested that HA/CPP modified paclitaxel plus tetrandrine micelles might provide a new strategy for treating gastric cancer.

Preparation and characterisation of tetrandrine nanosuspensions and in vitro estimate antitumour activity on A549 lung cancer cell line

Aim: The aim of this study was to improve solubility and antitumour ability in vitro of tetrandrine (Tet) via preparing nanosuspensions (NSs).Methods: The Tet-NSs were prepared by wet media milling. The Tet-CCS-NS was prepared with croscarmellose sodium (CCS) as single stabiliser. The Tet-HACC-TPGS-NS was manufactured with D-α-tocopheryl polyethylene glycol 1,000 succinate (TPGS) and hydroponically trimethyl ammonium chloride chitosan (HACC) as combined stabilisers. Physicochemical properties of the NSs such as particle size, surface morphologies, crystallinity and molecular interactions were investigated. In addition, the in vitro dissolution and antitumour activities using A549 human lung cancer cells were evaluated.Results: The mean particle sizes and Zeta potential of freshly prepared Tet-CCS-NS, Tet-HACC-TPGS-NS were 469.1 ± 14nm and 157.3 ± 5nm, -29.4 ± 0.26 mV and 23.3 ± 0.36 mV, respectively. In comparison to pure Tet, the cumulative dissolution of Tet-NSs were increased by 4 ∼ 5 times in 2 h. In vitro antitumour studies on Tet- NSs in A549 cells, the cell survival rate of the Tet-NSs at high concentration (30-50µg/ml) were less than 10% within 48 h. Meanwhile, Tet-NSs were revealed to induce A549 cells apoptosis and promote cell uptake.Conclusion: The present study has proved that the Tet-NSs can increase Tet solubility as well as improve Tet antitumour activity in vitro.

The Effect of Nanosystems on ATP-Binding Cassette Transporters: Understanding the Influence of Nanosystems on Multidrug Resistance Protein-1 and P-glycoprotein

The cancer multidrug resistance is involved in the failure of several treatments during cancer treatment. It is a phenomenon that has been receiving great attention in the last years due to the sheer amount of mechanisms discovered and involved in the process of resistance which hinders the effectiveness of many anti-cancer drugs. Among the mechanisms involved in the multidrug resistance, the participation of ATP-binding cassette (ABC) transporters is the main one. The ABC transporters are a group of plasma membrane and intracellular organelle proteins involved in the process of externalization of substrates from cells, which are expressed in cancer. They are involved in the clearance of intracellular metabolites as ions, hormones, lipids and other small molecules from the cell, affecting directly and indirectly drug absorption, distribution, metabolism and excretion. Other mechanisms responsible for resistance are the signaling pathways and the anti- and pro-apoptotic proteins involved in cell death by apoptosis. In this study we evaluated the influence of three nanosystem (Graphene Quantum Dots (GQDs), mesoporous silica (MSN) and poly-lactic nanoparticles (PLA)) in the main mechanism related to the cancer multidrug resistance such as the Multidrug Resistance Protein-1 and P-glycoprotein. We also evaluated this influence in a group of proteins involved in the apoptosis-related resistance including cIAP-1, XIAP, Bcl-2, BAK and Survivin proteins. Last, colonogenic and MTT (3-(4,5-dimethylthiazol-2-yl)- 2,5-diphenyltetrazolium bromide) assays have also been performed. The results showed, regardless of the concentration used, GQDs, MSN and PLA were not cytotoxic to MDA-MB-231 cells and showed no impairment in the colony formation capacity. In addition, it has been observed that P-gp membrane expression was not significantly altered by any of the three nanomaterials. The results suggest that GQDs nanoparticles would be suitable for the delivery of other multidrug resistance protein 1 (MRP1) substrate drugs that bind to the transporter at the same binding pocket, while MSN can strongly inhibit doxorubicin efflux by MRP1. On the other hand, PLA showed moderate inhibition of doxorubicin efflux by MRP1 suggesting that this nanomaterial can also be useful to treat MDR (Multidrug resistance) due to MRP1 overexpression.

Improvement of conventional anti-cancer drugs as new tools against multidrug resistant tumors

Multidrug resistance (MDR) is the dominant cause of the failure of cancer chemotherapy. The design of antitumor drugs that are able to evade MDR is rapidly evolving, showing that this area of biomedical research attracts great interest in the scientific community. The current review explores promising recent approaches that have been developed with the aim of circumventing or overcoming MDR. Encouraging results have been obtained in the investigation of the MDR-modulating properties of various classes of natural compounds and their analogues. Inhibition of P-gp or downregulation of its expression have proven to be the main mechanisms by which MDR can be surmounted. The use of hybrid molecules that are able to simultaneously interact with two or more cancer cell targets is currently being explored as a means to circumvent drug resistance. This strategy is based on the design of hybrid compounds that are obtained either by merging the structural features of separate drugs, or by conjugating two drugs or pharmacophores via cleavable/non-cleavable linkers. The approach is highly promising due to the pharmacokinetic and pharmacodynamic advantages that can be achieved over the independent administration of the two individual components. However, it should be stressed that the task of obtaining successful multivalent drugs is a very challenging one. The conjugation of anticancer agents with nitric oxide (NO) donors has recently been developed, creating a particular class of hybrid that can combat tumor drug resistance. Appropriate NO donors have been shown to reverse drug resistance via nitration of ABC transporters and by interfering with a number of metabolic enzymes and signaling pathways. In fact, hybrid compounds that are produced by covalently attaching NO-donors and antitumor drugs have been shown to elicit a synergistic cytotoxic effect in a variety of drug resistant cancer cell lines. Another strategy to circumvent MDR is based on nanocarrier-mediated transport and the controlled release of chemotherapeutic drugs and P-gp inhibitors. Their pharmacokinetics are governed by the nanoparticle or polymer carrier and make use of the enhanced permeation and retention (EPR) effect, which can increase selective delivery to cancer cells. These systems are usually internalized by cancer cells via endocytosis and accumulate in endosomes and lysosomes, thus preventing rapid efflux. Other modalities to combat MDR are described in this review, including the pharmaco-modulation of acridine, which is a well-known scaffold in the development of bioactive compounds, the use of natural compounds as means to reverse MDR, and the conjugation of anticancer drugs with carriers that target specific tumor-cell components. Finally, the outstanding potential of in silico structure-based methods as a means to evaluate the ability of antitumor drugs to interact with drug transporters is also highlighted in this review. Structure-based design methods, which utilize 3D structural data of proteins and their complexes with ligands, are the most effective of the in silico methods available, as they provide a prediction regarding the interaction between transport proteins and their substrates and inhibitors. The recently resolved X-ray structure of human P-gp can help predict the interaction sites of designed compounds, providing insight into their binding mode and directing possible rational modifications to prevent them from becoming P-gp drug substrates. In summary, although major efforts were invested in the search for new tools to combat drug resistant tumors, they all require further implementation and methodological development. Further investigation and progress in the abovementioned strategies will provide significant advances in the rational combat against cancer MDR.

The Application of Nanotechnology in the Codelivery of Active Constituents of Plants and Chemotherapeutics for Overcoming Physiological Barriers during Antitumor Treatment

Antitumor therapy using a combination of drugs has shown increased clinical efficacy. Active constituents derived from plants can offer several advantages, such as high efficiacy, low toxicity, extensive effects, and multiple targets. At present, the combination of plants' active constituents and chemotherapeutic drugs has attracted increased attention. Nanodrug delivery systems (NDDSs) have been widely used in tumor-targeted therapy because of their efficacy of delivering antitumor drugs. The in vivo process of tumor-targeted NDDSs has several steps. They include blood circulation, tumor accumulation and penetration, target cell internalization and uptake, and drug release and drug response. In each step, NDDSs encounter multiple barriers that prevent their effective delivery to target sites. Studies have been performed to find alternative strategies to overcome these barriers. We reviewed the recent progress of codelivery of active constituents of plants and chemotherapeutics using NDDSs. Progress into transversing the physiological barriers for more effective in vivo antitumor delivery will be discussed in this review.

Peptide-Conjugated Nanoparticles as Targeted Anti-angiogenesis Therapeutic and Diagnostic in Cancer

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Targeting angiogenesis in the microenvironment of a tumor can enable suppression of tumor angiogenesis and delivery of anticancer drugs into the tumor. Anti-angiogenesis targeted delivery systems utilizing passive targeting such as Enhanced Permeability and Retention (EPR) and specific receptor-mediated targeting (active targeting) should result in tumor-specific targeting. One targeted anti-angiogenesis approach uses peptides conjugated to nanoparticles, which can be loaded with anticancer agents. Anti-angiogenesis agents can suppress tumor angiogenesis and thereby affect tumor growth progression (tumor growth arrest), which may be further reduced with the targetdelivered anticancer agent. This review provides an update of tumor vascular targeting for therapeutic and diagnostic applications, with conventional or long-circulating nanoparticles decorated with peptides that target neovascularization (anti-angiogenesis) in the tumor microenvironment.

Accumulated cytotoxicity of CDK inhibitor dinaciclib with first-line chemotherapy drugs in salivary adenoid cystic carcinoma cells

Adenoid cystic carcinoma (ACC) is one of the most common salivary gland malignant tumors. Its treatment failure is partly due to the limitations of chemotherapeutic agents and their adverse effects. The objective of this study was to determine the potential additive anti-cancer effect of a novel CDK inhibitor dinaciclib with first-line chemotherapy drugs in ACC. Protein expression of phosphorylated CDK2 (p-CDK2) in paraffin-embedded tissue specimens of ACC from 17 patients was investigated by immunohistochemistry (IHC). Cell Counting Kit (CCK-8), clone formation assay, and flow cytometry were used to test the proliferation and apoptosis of ACC-2 cells treated with dinaciclib with or without other first-line chemotherapy drugs. Protein expression was also determined by Western blot. Interestingly, we discovered that p-CDK2 protein was expressed in both cytoplasmic and nucleus in salivary ACC tissues, which was higher than that in normal salivary tissues, indicating that agents targeting CDK2 may be potential therapeutic strategies against this type of tumor. As expected, CDK inhibitor dinaciclib significantly induced ACC-2 cells apoptosis. Moreover, it sensitized cells to the chemotherapeutic agents such as cisplatin, pemetrexed, and etoposide (VP-16), and this effect by dinaciclib may induce cell cycle arrest via abrogating CDK2 activity. Therefore, combinational therapy of CDK inhibitor dinaciclib with first-line chemotherapy drugs may be a promising strategy in the treatment of salivary ACC.

Multicompartmental lipid–protein nanohybrids for combined tretinoin/herbal lung cancer therapy

Aim: Multicompartmental lipid–protein nanohybrids (MLPNs) were developed for combined delivery of the anticancer drugs tretinoin (TRE) and genistein (GEN) as synergistic therapy of lung cancer. Materials & methods: The GEN-loaded lipid core was first prepared and then coated with TRE-loaded zein shell via nanoprecipitation. Results: TRE/GEN-MLPNs demonstrated a size of 154.5 nm. In situ ion pair formation between anionic TRE and the cationic stearyl amine improved the drug encapsulation with enhanced stability of MLPNs. TRE/GEN-coloaded MLPNs were more cytotoxic against A549 cancer cells compared with combined free GEN/TRE. In vivo, lung cancer bearing mice treated with TRE/GEN-MLPNs displayed higher apoptotic caspase activation compared with mice-treated free combined GEN/TRE. Conclusion: TRE/GEN-MLPNs might serve as a promising parenteral nanovehicles for lung cancer therapy.

iRGD: A Promising Peptide for Cancer Imaging and a Potential Therapeutic Agent for Various Cancers

Poor penetration into the tumor parenchyma and the reduced therapeutic efficacy of anticancer drugs and other medications are the major problems in tumor treatment. A new tumor-homing and penetrating peptide, iRGD (CRGDK/RGPD/EC), can be effectively used to combine and deliver imaging agents or anticancer drugs into tumors. The different “vascular zip codes” expressed in different tissues can serve as targets for docking-based (synaptic) delivery of diagnostic and therapeutic molecules. αv-Integrins are abundantly expressed in the tumor vasculature, where they are recognized by peptides containing the RGD integrin recognition motif. The iRGD peptide follows a multistep tumor-targeting process: First, it is proteolytically cleaved to generate the CRGDK fragment by binding to the surface of cells expressing αv integrins (αvβ3 and αvβ5). Then, the fragment binds to neuropilin-1 and penetrates the tumor parenchyma more deeply. Compared with conventional RGD peptides, the affinity of iRGD for αv integrins is in the mid to low nanomolar range, and the CRGDK fragment has a stronger affinity for neuropilin-1 than that for αv integrins because of the C-terminal exposure of a conditional C-end Rule (CendR) motif (R/KXXR/K), whose receptor proved to be neuropilin-1. Consequently, these advantages facilitate the transfer of CRGDK fragments from integrins to neuropilin-1 and consequently deeper penetration into the tumor. Due to its specific binding and strong affinity, the iRGD peptide can deliver imaging agents and anticancer drugs into tumors effectively and deeply, which is useful in detecting the tumor, blocking tumor growth, and inhibiting tumor metastasis. This review aims to focus on the role of iRGD in the imaging and treatment of various cancers.

Polymeric Co-Delivery Systems in Cancer Treatment: An Overview on Component Drugs' Dosage Ratio Effect

Multiple factors are involved in the development of cancers and their effects on survival rate. Many are related to chemo-resistance of tumor cells. Thus, treatment with a single therapeutic agent is often inadequate for successful cancer therapy. Ideally, combination therapy inhibits tumor growth through multiple pathways by enhancing the performance of each individual therapy, often resulting in a synergistic effect. Polymeric nanoparticles prepared from block co-polymers have been a popular platform for co-delivery of combinations of drugs associated with the multiple functional compartments within such nanoparticles. Various polymeric nanoparticles have been applied to achieve enhanced therapeutic efficacy in cancer therapy. However, reported drug ratios used in such systems often vary widely. Thus, the same combination of drugs may result in very different therapeutic outcomes. In this review, we investigated polymeric co-delivery systems used in cancer treatment and the drug combinations used in these systems for synergistic anti-cancer effect. Development of polymeric co-delivery systems for a maximized therapeutic effect requires a deeper understanding of the optimal ratio among therapeutic agents and the natural heterogenicity of tumors.

Co-Delivery Nanosystems for Cancer Treatment: A Review

Massive data available on cancer therapy more than ever lead our mind to the general concept that there is no perfect treatment for cancer. Indeed, the biological complexity of this disease is too excessive to be treated by a single therapeutic approach. Current delivery systems containing a specific drug or gene have their particular opportunities and restrictions. It is worth noting that a considerable number of studies suggest that single- drug delivery systems result in insufficient suppression of cancer growth. Therefore, one of the main ideas of co-delivery system designing is to enhance the intended response or to achieve the synergistic/combined effect compared to the single drug strategy. This review focuses on various strategies for co-delivery of therapeutic agents in the treatment of cancer. The primary approaches within the script are categorized into co-delivery of conventional chemotherapeutics, gene-based molecules, and plant-derived materials. Each one is explained in examples with the recent researches. In the end, a brief summary is provided to conclude the gist of the review.

Tumor heterogeneity and nanoparticle-mediated tumor targeting: the importance of delivery system personalization

After the discovery of the enhanced permeability and retention effect in 1986, it was envisioned that nanoparticle-mediated tumor-targeted delivery of chemotherapeutics would make a radical change in cancer therapy. However, after three decades of extensive research, only a few nanotherapeutics have been approved for clinical use. Although significant advantages of nanomedicines have been demonstrated in pre-clinical studies, clinical outcome was found to be variable. Advanced research has revealed that significant biochemical and structural variations exist between (and among) different tumors. These variations can considerably affect the tumor delivery and efficacy of nanomedicines. Tumor penetration is an important determining factor for positive therapeutic outcome and same nanomedicine can show diverse efficacy against different tumors depending on the extent of tumor accumulation and penetration. Recent research has started shading light on how the tumor variations can influence nanoparticle tumor delivery. These findings indicate that there is no "ideal" design of nanoparticles for exhibiting equally high efficacy against a broad spectrum of tumors. For achieving maximum benefit of the nanotherapeutics, it is necessary to analyze the tumor microenvironment for understanding the biological and structural characteristics of the tumor. Designing of the nanomedicine should be done according to the tumor characteristics. In this comprehensive review, we have first given a brief overview of the design characteristics of nanomedicine which impact their tumor delivery. Then we discussed about the variability in the tumor architecture and how it influences nanomedicine delivery. Finally, we have discussed the possibility of delivery system personalization based on the tumor characteristics.

Triphenylphosphonium-modified mitochondria-targeted paclitaxel nanocrystals for overcoming multidrug resistance

Mitochondria are currently known as novel targets for treating cancer, especially for tumors displaying multidrug resistance (MDR). This present study aimed to develop a mitochondria-targeted delivery system by using triphenylphosphonium cation (TPP⁺)-conjugated Brij 98 as the functional stabilizer to modify paclitaxel (PTX) nanocrystals (NCs) against drug-resistant cancer cells. Evaluations were performed on 2D monolayer and 3D multicellular spheroids (MCs) of MCF-7 cells and MCF-7/ADR cells. In comparison with free PTX and the non-targeted PTX NCs, the targeted PTX NCs showed the strongest cytotoxicity against both 2D MCF-7 and MCF-7/ADR cells, which was correlated with decreased mitochondrial membrane potential. The targeted PTX NCs exhibited deeper penetration on MCF-7 MCs and more significant growth inhibition on both MCF-7 and MCF-7/ADR MCs. The proposed strategy indicated that the TPP⁺-modified NCs represent a potentially viable approach for targeted chemotherapeutic molecules to mitochondria. This strategy might provide promising therapeutic outcomes to overcome MDR.