MDR in cancer: Addressing the underlying cellular alterations with the use of nanocarriers

Unraveling the noncoding RNA landscape in glioblastoma: from pathogenesis to precision therapeutics

Glioblastoma (GBM) is an aggressive type IV brain tumor that originates from astrocytes and has a poor prognosis. Despite intensive research, survival rates have not significantly improved. Noncoding RNAs (ncRNAs) are emerging as critical regulators of carcinogenesis, progression, and increased treatment resistance in GBM cells. They influence angiogenesis, migration, epithelial-to-mesenchymal transition, and invasion in GBM cells. ncRNAs, such as long ncRNAs (lncRNAs), microRNAs (miRNAs), and circular RNAs (circRNAs), are commonly dysregulated in GBM. miRNAs, such as miR-21, miR-133a, and miR-27a-3p, are oncogenes that increase cell proliferation, metastasis, and migration by targeting TGFBR1 and BTG2. In contrast, lncRNAs, such as HOXD-AS2 and LINC00511, are oncogenes that increase the migration, invasion, and proliferation of cells. CircRNAs, such as circ0001730, circENTPD7, and circFOXO3, are oncogenes responsible for cell growth, angiogenesis, and viability. Developing novel therapeutic strategies targeting ncRNAs, cell migration, and angiogenesis is a promising approach for GBM. By targeting these dysregulated ncRNAs, we can potentially restore a healthy balance in gene expression and influence disease progression. ncRNAs abound within GBM, demonstrating significant roles in governing the growth and behavior of these tumors. They may also be useful as biomarkers or targets for therapy. The use of morpholino oligonucleotides (MOs) suppressing the oncogene expression of HOTAIR, BCYRN1, and cyrano, antisense oligonucleotides (ASOs) suppressing the expression of ncRNAs such as MALAT1 and miR-10b, locked nucleic acids (LNAs) suppressing miR-21, and peptide nucleic acids (PNAs) suppressing the expression of miR-155 inhibited the PI3K pathway, tumor growth, angiogenesis, proliferation, migration, and invasion. Targeting oncogenic ncRNAs with RNA-interfering strategies such as MOs, ASOs, LNAs, CRISPR-Cas9 gene editing, and PNA approaches may represent a promising therapeutic strategy for GBM. This review emphasizes the critical role of ncRNAs in GBM pathogenesis, as well as the potential for new therapeutic strategies targeting these pathways to improve the prognosis and quality of life for GBM patients.

Nuclear factor-κB activation by transforming growth factor-β1 drives tumour microenvironment-mediated drug resistance in neuroblastoma

BACKGROUND

Intrinsic and extrinsic factors in the tumour microenvironment (TME) contribute to therapeutic resistance. Here we demonstrate that transforming growth factor (TGF)-β1 produced in the TME increased drug resistance of neuroblastoma (NB) cells.

METHODS

Human NB cell lines were tested in vitro for their sensitivity to Doxorubicin (DOX) and Etoposide (ETOP) in the presence of tumour-associated macrophages (TAM) and mesenchymal stromal cells/cancer-associated fibroblasts (MSC/CAF). These experiments were validated in xenotransplanted and primary tumour samples.

RESULTS

Drug resistance was associated with an increased expression of efflux transporter and anti-apoptotic proteins. Upregulation was dependent on activation of nuclear factor (NF)-κB by TGF-β-activated kinase (TAK1) and SMAD2. Resistance was reversed upon pharmacologic and genetic inhibitions of NF-κB, and TAK1/SMAD2. Interleukin-6, leukaemia inhibitory factor and oncostatin M were upregulated by this TGF-β/TAK1/NF-κB/SMAD2 signalling pathway contributing to drug resistance via an autocrine loop activating STAT3. An analysis of xenotransplanted NB tumours revealed an increased presence of phospho (p)-NF-κB in tumours co-injected with MSC/CAF and TAM, and these tumours failed to respond to Etoposide but responded if treated with a TGF-βR1/ALK5 inhibitor. Nuclear p-NF-κB was increased in patient-derived tumours rich in TME cells.

CONCLUSIONS

The data provides a novel insight into a targetable mechanism of environment-mediated drug resistance.

Oncostatin M reverses ABCG2-mediated mitoxantrone resistance

Mitoxantrone resistant variant of SW620 line was developed, characterized and subsequently used as a model system to determine oncostatin M ability to modulate MDR phenomenon. The selection regimen allowed for overexpression of ABCG2 and ABCB1 both at the RNA and protein level, which was further confirmed by functional assays. Oncostatin M supplementation resulted in partial reversal of MDR phenotype by decreasing overexpression of ABCG2 demonstrating for the first time the ability of this cytokine for selective down-regulation of one of MDR proteins.

Membrane-Fusing Vehicles for Re-Sensitizing Transporter-Mediated Multiple-Drug Resistance in Cancer

Reversing the multiple drug resistance (MDR) arising from the overexpression of the efflux transporters often fails mainly due to the high toxicity or the poor water solubility of the inhibitors of these transporters. Here, we demonstrate the delivery of an inhibitor targeting three ABC transporters (ABCB1, ABCC1 and ABCG2) directly to the cell membrane using membrane-fusing vehicles (MFVs). Three different transfected MDCK II cell lines, along with parental cells, were used to investigate the inhibitory effect of cyclosporine A (CsA) in solution versus direct delivery to the cell membrane. CsA-loaded MFVs successfully reversed MDR for all three investigated efflux transporters at significantly lower concentrations compared with CsA in solution. Results showed a 15-fold decrease in the IC50 value for ABCB1, a 7-fold decrease for ABCC1 and an 11-fold decrease for ABCG2. We observed binding site specificity for ABCB1 and ABCG2 transporters. Lower concentrations of empty MFVs along with CsA contribute to the inhibition of Hoechst 33342 efflux. However, higher concentrations of CsA along with the high amount of MFVs activated transport via the H-binding site. This supports the conclusion that MFVs can be useful beyond their role as delivery systems and also help to elucidate differences between these transporters and their binding sites.

Nanocarriers address intracellular barriers for efficient drug delivery, overcoming drug resistance, subcellular targeting and controlled release

The cellular barriers are major bottlenecks for bioactive compounds entering into cells to accomplish their biological functions, which limits their biomedical applications. Nanocarriers have demonstrated high potential and benefits for encapsulating bioactive compounds and efficiently delivering them into target cells by overcoming a cascade of intracellular barriers to achieve desirable therapeutic and diagnostic effects. In this review, we introduce the cellular barriers ahead of drug delivery and nanocarriers, as well as summarize recent advances and strategies of nanocarriers for increasing internalization with cells, promoting intracellular trafficking, overcoming drug resistance, targeting subcellular locations and controlled drug release. Lastly, the future perspectives of nanocarriers for intracellular drug delivery are discussed, which mainly focus on potential challenges and future directions. Our review presents an overview of intracellular drug delivery by nanocarriers, which may encourage the future development of nanocarriers for efficient and precision drug delivery into a wide range of cells and subcellular targets.

Overcoming drug resistance with specific nano scales to targeted therapy: Focused on metastatic cancers

Metastatic cancer, which accounts for the majority of cancer fatalities, is a difficult illness to treat. Currently used cancer treatments include radiation therapy, chemotherapy, surgery, and targeted treatment (immune, gene, and hormonal). The disadvantages of these treatments include a high risk of tumor recurrence and surgical complications that may result in permanent deformities. On the other hand, most chemotherapy drugs are small molecules, which usually have unfavorable side effects, low absorption, poor selectivity, and multi-drug resistance. Anticancer drugs can be delivered precisely to the cancer spot by encapsulating them to reduce side effects. Stimuli-responsive nanocarriers can be used for drug release at cancer sites and provide target-specific delivery. As previously stated, metastasis is the primary cause of cancer-related mortality. We have evaluated the usage of nano-medications in the treatment of some metastatic tumors.

Tumor microenvironment diversity and plasticity in cancer multidrug resistance

Multidrug resistance (MDR) poses a significant obstacle to effective cancer treatment, and the tumor microenvironment (TME) is crucial for MDR development and reversal. The TME plays an active role in promoting MDR through several pathways. However, a promising therapeutic approach for battling MDR involves targeting specific elements within the TME. Therefore, this comprehensive review elaborates on the research developments regarding the dual role of the TME in promoting and reversing MDR in cancer. Understanding the complex role of the TME in promoting and reversing MDR is essential to developing effective cancer therapies. Utilizing the adaptability of the TME by targeting novel TME-specific factors, utilizing combination therapies, and employing innovative treatment strategies can potentially combat MDR and achieve personalized treatment outcomes for patients with cancer.

Identification and functional analysis of ABC transporter genes related to deltamethrin resistance in Culex pipiens pallens

BACKGROUND

Pathogens that reproduce or develop in mosquitoes can transmit several diseases, endanger human health, and overwhelm health systems. Synthetic pyrethroids are the most widely used insecticides against adult mosquitoes, but their widespread use has led to resistance. The adenosine triphosphate (ATP)-binding cassette (ABC) transporters are involved in the resistance monitoring of insects, but their role and underlying mechanisms in insecticide resistance have not been fully elucidated. In the present study, we identified ABC transporter genes in Culex pipiens and investigated their role in the development of insecticide resistance.

RESULTS

We identified 63 ABC transporter genes in Cx. pipiens and classified them as per the ABC transporter subfamilies. We also performed phylogenetic analysis. The knockdown rate of the mosquitoes orally fed with the ABC transporter inhibitor verapamil increased after deltamethrin treatment compared with that of the control group. Several genes from the ABCB, ABCC, and ABCG subfamilies were highly expressed in resistant mosquitoes. Immunofluorescence analysis revealed that ABCG6032427 was expressed in the head, chest, abdomen, wings, and legs, and the expression was the highest in the legs. Subsequently, knockdown of ABCG6032427 using RNA interference (RNAi) increased the sensitivity of the mosquitoes to deltamethrin, and scanning and transmission electron microscopy revealed that ABCG6032427 knockdown reduced cuticle thickness and the cuticle became loose and irregular.

CONCLUSIONS

ABCG6032427 may modulate cuticle thickness and structure, thus play an important role in the development of deltamethrin resistance in mosquitoes. Thus, it could be a potential target for deltamethrin resistance management in Cx. pipiens. © 2023 Society of Chemical Industry.

The Battlefield of Chemotherapy in Pediatric Cancers

The survival rate for pediatric cancers has remarkably improved in recent years. Conventional chemotherapy plays a crucial role in treating pediatric cancers, especially in low- and middle-income countries where access to advanced treatments may be limited. The Food and Drug Administration (FDA) approved chemotherapy drugs that can be used in children have expanded, but patients still face numerous side effects from the treatment. In addition, multidrug resistance (MDR) continues to pose a major challenge in improving the survival rates for a significant number of patients. This review focuses on the severe side effects of pediatric chemotherapy, including doxorubicin-induced cardiotoxicity (DIC) and vincristine-induced peripheral neuropathy (VIPN). We also delve into the mechanisms of MDR in chemotherapy to the improve survival and reduce the toxicity of treatment. Additionally, the review focuses on various drug transporters found in common types of pediatric tumors, which could offer different therapeutic options.

Functionalized Lipid Nanocarriers for Simultaneous Delivery of Docetaxel and Tariquidar to Chemoresistant Cancer Cells

The simultaneous drug delivery efficiency of a co-loaded single-carrier system of docetaxel (DTX)- and tariquidar (TRQ)-loaded nanostructured lipid carrier (NLC) functionalized with PEG and RIPL peptide (PRN) (D^T-PRN) was compared with that of a physically mixed dual-carrier system of DTX-loaded PRN (D-PRN) and TRQ-loaded PRN (T-PRN) to overcome DTX mono-administration-induced multidrug resistance. NLC samples were prepared using the solvent emulsification evaporation technique and showed homogeneous spherical morphology, with nano-sized dispersion (<220 nm) and zeta potential values of −15 to −7 mV. DTX and/or TRQ was successfully encapsulated in NLC samples (>95% encapsulation efficiency and 73–78 µg/mg drug loading). In vitro cytotoxicity was concentration-dependent; D^T-PRN exhibited the highest MDR reversal efficiency, with the lowest combination index value, and increased the cytotoxicity and apoptosis in MCF7/ADR cells by inducing cell-cycle arrest in the G2/M phase. A competitive cellular uptake assay using fluorescent probes showed that, compared to the dual nanocarrier system, the single nanocarrier system exhibited better intracellular delivery efficiency of multiple probes to target cells. In the MCF7/ADR-xenografted mouse models, simultaneous DTX and TRQ delivery using D^T-PRN significantly suppressed tumor growth as compared to other treatments. A single co-loaded system for PRN-based co-delivery of DTX/TRQ (1:1, w/w) constitutes a promising therapeutic strategy for drug-resistant breast cancer cells.

Purinergic signaling: Diverse effects and therapeutic potential in cancer

Regardless of improved biological insights and therapeutic advances, cancer is consuming multiple lives worldwide. Cancer is a complex disease with diverse cellular, metabolic, and physiological parameters as its hallmarks. This instigates a need to uncover the latest therapeutic targets to advance the treatment of cancer patients. Purines are building blocks of nucleic acids but also function as metabolic intermediates and messengers, as part of a signaling pathway known as purinergic signaling. Purinergic signaling comprises primarily adenosine triphosphate (ATP) and adenosine (ADO), their analogous membrane receptors, and a set of ectonucleotidases, and has both short- and long-term (trophic) effects. Cells release ATP and ADO to modulate cellular function in an autocrine or paracrine manner by activating membrane-localized purinergic receptors (purinoceptors, P1 and P2). P1 receptors are selective for ADO and have four recognized subtypes-A1, A2A, A2B, and A3. Purines and pyrimidines activate P2 receptors, and the P2X subtype is ligand-gated ion channel receptors. P2X has seven subtypes (P2X1-7) and forms homo- and heterotrimers. The P2Y subtype is a G protein-coupled receptor with eight subtypes (P2Y1/2/4/6/11/12/13/14). ATP, its derivatives, and purinoceptors are widely distributed in all cell types for cellular communication, and any imbalance compromises the homeostasis of the cell. Neurotransmission, neuromodulation, and secretion employ fast purinergic signaling, while trophic purinergic signaling regulates cell metabolism, proliferation, differentiation, survival, migration, invasion, and immune response during tumor progression. Thus, purinergic signaling is a prospective therapeutic target in cancer and therapy resistance.

Exploring the Use of Cold Atmospheric Plasma to Overcome Drug Resistance in Cancer

Drug resistance is a major problem in cancer treatment, as it limits the effectiveness of pharmacological agents and can lead to disease progression. Cold atmospheric plasma (CAP) is a technology that uses ionized gas (plasma) to generate reactive oxygen and nitrogen species (RONS) that can kill cancer cells. CAP is a novel approach for overcoming drug resistance in cancer. In recent years, there has been a growing interest in using CAP to enhance the effectiveness of chemotherapy drugs. In this review, we discuss the mechanisms behind this phenomenon and explore its potential applications in cancer treatment. Going through the existing literature on CAP and drug resistance in cancer, we highlight the challenges and opportunities for further research in this field. Our review suggests that CAP could be a promising option for overcoming drug resistance in cancer and warrants further investigation.

Recent advances in anti-multidrug resistance for nano-drug delivery system

Chemotherapy for tumors occasionally results in drug resistance, which is the major reason for the treatment failure. Higher drug doses could improve the therapeutic effect, but higher toxicity limits the further treatment. For overcoming drug resistance, functional nano-drug delivery system (NDDS) has been explored to sensitize the anticancer drugs and decrease its side effects, which are applied in combating multidrug resistance (MDR) via a variety of mechanisms including bypassing drug efflux, controlling drug release, and disturbing metabolism. This review starts with a brief report on the major MDR causes. Furthermore, we searched the papers from NDDS and introduced the recent advances in sensitizing the chemotherapeutic drugs against MDR tumors. Finally, we concluded that the NDDS was based on several mechanisms, and we looked forward to the future in this field.

New Iron Metabolic Pathways and Chelation Targeting Strategies Affecting the Treatment of All Types and Stages of Cancer

There is new and increasing evidence from in vitro, in vivo and clinical studies implicating the pivotal role of iron and associated metabolic pathways in the initiation, progression and development of cancer and in cancer metastasis. New metabolic and toxicity mechanisms and pathways, as well as genomic, transcription and other factors, have been linked to cancer and many are related to iron. Accordingly, a number of new targets for iron chelators have been identified and characterized in new anticancer strategies, in addition to the classical restriction of/reduction in iron supply, the inhibition of transferrin iron delivery, the inhibition of ribonucleotide reductase in DNA synthesis and high antioxidant potential. The new targets include the removal of excess iron from iron-laden macrophages, which affects anticancer activity; the modulation of ferroptosis; ferritin iron removal and the control of hyperferritinemia; the inhibition of hypoxia related to the role of hypoxia-inducible factor (HIF); modulation of the function of new molecular species such as STEAP4 metalloreductase and the metastasis suppressor N-MYC downstream-regulated gene-1 (NDRG1); modulation of the metabolic pathways of oxidative stress damage affecting mitochondrial function, etc. Many of these new, but also previously known associated iron metabolic pathways appear to affect all stages of cancer, as well as metastasis and drug resistance. Iron-chelating drugs and especially deferiprone (L1), has been shown in many recent studies to fulfill the role of multi-target anticancer drug linked to the above and also other iron targets, and has been proposed for phase II trials in cancer patients. In contrast, lipophilic chelators and their iron complexes are proposed for the induction of ferroptosis in some refractory or recurring tumors in drug resistance and metastasis where effective treatments are absent. There is a need to readdress cancer therapy and include therapeutic strategies targeting multifactorial processes, including the application of multi-targeting drugs involving iron chelators and iron-chelator complexes. New therapeutic protocols including drug combinations with L1 and other chelating drugs could increase anticancer activity, decrease drug resistance and metastasis, improve treatments, reduce toxicity and increase overall survival in cancer patients.

Robust Dual Enzyme Cascade-Catalytic Cholesterol Depletion for Reverse Tumor Multidrug Resistance

Although combination drugs and P-glycoprotein inhibitors are the main methods to solve multidrug resistance, these methods ignore the pathological structure of drug-resistant cells and extremely limit curative effect. Herein, a new paradigm of reversing multidrug resistance with abnormal expression of cholesterol as the target is proposed, which uses the cascade catalysis of "natural enzyme" cholesterol oxidase (COD) and "nanoenzyme" Cu²⁺ -modified zirconium-based metal-organic framework (ZrMOF(Cu)) to convert cholesterol into the highly cytotoxic hydroxyl radicals. The doxorubicin (DOX)-loaded nanoparticles (DOX@COD-MOF) can significantly reduce the cholesterol content of cancer cells via COD, which decrease the rigidity of drug resistant cancer cell membranes and restore the sensitivity of multidrug-resistant cells to DOX. Afterward, DOX@COD-MOF is encapsulated by cancer cell membranes (CCM) to construct a bionic "dual enzyme catalytic cascade nanoreactor" (DOX@COD-MOF@CCM). Such a rational design presents a preferential accumulation tendency to tumor sites due to the homologous targeting mechanism of CCM, and affords 94.4% in tumor growth suppression without systemic toxicity in vivo. This work aims to achieve the therapeutic purpose of high efficiency and low toxicity. It has the characteristics of "converting enemy into friend, " and opens up a promising way for effectively reversing multidrug resistance of tumors.

Synergistic antitumor efficacy of PD-1-conjugated PTX- and ZSQ-loaded nanoliposomes against multidrug-resistant liver cancers

Hepatocellular carcinoma (HCC) is one of the most common malignancies worldwide with poor chemotherapeutic efficiency due to multidrug resistance (MDR); it is very important to develop a targeted nanocarrier for the treatment of HCC. In this study, a programmed death ligand 1 (PD-L1)-conjugated nanoliposome was constructed for co-delivery of paclitaxel (PTX) and P-glycoprotein (P-gp) inhibitor zosuquidar (ZSQ) to overcome MDR in human HCC cells and tumors in vivo. Transmission electron microscopy (TEM) and nanoparticle tracking analysis (NTA) were used to examine the nanoparticles morphology and size; PD-1-conjugated PTX and ZSQ-loaded nanoliposomes (PD-PZLP) revealed a spherical shape with a size of 139.5 ± 10.7 nm. Then, the physicochemical properties, as well as the drug loading capacity, release profile, cellular uptake, and cytotoxicity of the dual drug-encapsulated nanoliposomes were characterized. PD-PZLP displayed a high drug loading capacity of 20 ~ 30% for both PTX and ZSQ; the drug release of PTX and ZSQ in pH 5.0 was significantly faster than in pH 7.4. Cellular uptake study demonstrated PD-PZLP had higher internalization efficiency than non-targeted PZLP. Terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) staining and reactive oxygen species (ROS) analysis demonstrated that PD-PZLP triggered an excessive ROS reaction and cell apoptosis compared with that of free PTX or ZSQ, which was also consistent with the cell antiproliferative effects in MTT assay. Furthermore, PD-PZLP could enhance synergistic antitumor effects on 7721/ADM xenograft tumor model, which also significantly alleviated hepatotoxicity as evident from the decreased aspartate transaminase (AST) and alanine transaminase (ALT) levels. Overall, PD-PZLP exhibited high loading capacity, significant synergistic effects, promising antitumor efficacy, and the lowest toxicity, which provide a promising strategy to overcome MDR in HCC.

Overcoming multidrug resistance by knockout of ABCB1 gene using CRISPR/Cas9 system in SW620/Ad300 colorectal cancer cells

Multidrug resistance (MDR) has been extensively reported in colorectal cancer patients, which remains a major cause of chemotherapy failure. One of the critical mechanisms of MDR in colorectal cancer is the reduced intracellular drug level led by the upregulated expression of the ATP-binding cassette (ABC) transporters, particularly, ABCB1/P-gp. In this study, the CRISPR/Cas9 system was utilized to target ABCB1 in MDR colorectal cancer SW620/Ad300 cell line with ABCB1 overexpression. The results showed that stable knockout of ABCB1 gene by the CRISPR/Cas9 system was achieved in the MDR cancer cells. Reversal of MDR against ABCB1 chemotherapeutic drugs increased intracellular accumulation of [3H]-paclitaxel accumulation, and decreased drug efflux activity was observed in MDR SW620/Ad300 cells after ABCB1 gene knockout. Further tests using the 3D multicellular tumor spheroid model suggested that deficiency in ABCB1 restrained tumor spheroid growth and restore sensitivity to paclitaxel in MDR tumor spheroids. Overall, the CRISPR/Cas9 system targeting the ABCB1 gene can be an effective approach to overcome ABCB1-mediated MDR in colorectal cancer SW620/Ad300 cells.

Dasatinib self-assembled nanoparticles decorated with hyaluronic acid for targeted treatment of tumors to overcome multidrug resistance

Multidrug resistance (MDR) and lack of targeting specificity are the main reasons why traditional drug therapies fail and produce toxic side effects in cancer chemotherapy. In order to increase targeting specificity and maximize therapeutic efficacy, new intelligent drug delivery systems are needed. In this study, we prepared the hyaluronic acid (HA) conjugated dasatinib (DAS) and D-α-tocopherol acid polyethylene glycolsuccinate (TPGS) copolymer nanoparticles (THD-NPs). The water solubility of the hydrophobic drug DAS was improved by chemically linking with HA. HA can bind to the over-expressed CD44 protein of tumor cells to increase targeting specificity, TPGS can inhibit the activity of P-glycoprotein (P-gp), and increase the intracellular accumulation of drugs. The prepared drug-loaded nanoparticle has a particle size of 82.23 ± 1.07 nm with good in vitro stability. Our in vitro studies showed that THD-NPs can be released more rapidly in a weakly acidic environment (pH = 5.5) than in a normal physiological environment (pH = 7.4), which can realize the selective release of nanoparticles in tumor cells. Compared to free drugs, THD-NPs showed more efficient cellular uptake, effectively increased the cytotoxic effect of DAS on nasopharyngeal carcinoma HNE1 cells drug resistance HNE1/DDP cells and increased the accumulation of drugs in HNE1/DDP cells, which may be due to the inhibitory effect of TPGS on the efflux function of P-gp. In vivo experiments showed that THD-NPs can effectively inhibit tumor growth without obvious side effects. In conclusion, the targeted and pH-sensitive nanosystem, we designed has great potential to overcome drug resistance and increase therapeutic effects in cancer treatment.

Rhinacanthin-C enhances chemosensitivity of breast cancer cells via the downregulation of P-glycoprotein through inhibition of Akt/NF-kappa B signaling pathway

Introduction: High expression of P-glycoprotein (P-gp) has been linked to multidrug resistance (MDR) and chemotherapeutic failure. Previously, we demonstrated that rhinacanthin-C, a naphthoquinone from Rhinacanthus nasutus, was able to enhance the cytotoxicity of doxorubicin against breast cancer MCF-7 cells via direct P-gp inhibition. In this study, we looked at its effect on P-gp downregulation and the mechanism involved in the resistance of MCF-7 cells to doxorubicin. Methods: Doxorubicin-resistant MCF-7 (MCF-7/DOX) cells were exposed to rhinacanthin-C for 24-48 hours prior to the assessment of their chemosensitivity via MTT assay, P-gp activity via calcein-AM uptake assay, P-gp expression, and signaling via qRT-PCR and western blot analyses. Results: Pretreatment with 1 µM of rhinacanthin-C for 48 hours significantly enhanced cytotoxicity of doxorubicin, as well as camptothecin and etoposide, to MCF-7/DOX cells. In the rhinacanthin-C-treated cells, reduction of MDR1 mRNA and P-gp levels and increased intracellular calcein were observed. Moreover, phosphorylation of Akt, NF-ᴋB and IκB-α, along with YB-1 expression, significantly decreased after 24-hour treatment with rhinacanthin-C. In contrast, the naphthoquinone had no effect on expression levels of ERK1/2 and phosphorylated ERK1/2 under similar conditions. Conclusion: Rhinacanthin-C, at a non-cytotoxic concentration (1 µM), could downregulate P-gp expression in MCF-7/DOX cells via the inhibition of the Akt/NF-ᴋB signaling pathway and YB-1 expression. Long-term exposure to this natural naphthoquinone may increase the chemosensitivity of cancer cells with MDR phenotype.

Progress in the study of D-α-tocopherol polyethylene glycol 1000 succinate (TPGS) reversing multidrug resistance

Currently, multidrug resistance (MDR) is one of the major reasons for failure in clinical cancer chemotherapy. Overexpression of the ATP binding cassette (ABC) transporter P-glycoprotein (P-gp), which significantly increases the efflux of anticancer drugs from tumor cells, enhances MDR. In the past few decades, four generations of P-gp inhibitors have appeared. However, they are limited in clinical application due to their severe toxic side effects. As a P-gp inhibitor and carrier for loading chemotherapy agents, TPGS has received increasing attention due to its advantages and unique properties of reversing MDR. TPGS is an amphipathic agent that increases the solubility of most chemotherapy drugs and decreases severe side effects. In addition, TPGS is an excellent carrier with P-gp-inhibiting ability. In this review, we summarize the latest articles on TPGS-based nanodelivery systems to prevent MDR.

Drug Resistance in Metastatic Breast Cancer: Tumor Targeted Nanomedicine to the Rescue

Breast cancer, specifically metastatic breast, is a leading cause of morbidity and mortality in women. This is mainly due to relapse and reoccurrence of tumor. The primary reason for cancer relapse is the development of multidrug resistance (MDR) hampering the treatment and prognosis. MDR can occur due to a multitude of molecular events, including increased expression of efflux transporters such as P-gp, BCRP, or MRP1; epithelial to mesenchymal transition; and resistance development in breast cancer stem cells. Excessive dose dumping in chemotherapy can cause intrinsic anti-cancer MDR to appear prior to chemotherapy and after the treatment. Hence, novel targeted nanomedicines encapsulating chemotherapeutics and gene therapy products may assist to overcome cancer drug resistance. Targeted nanomedicines offer innovative strategies to overcome the limitations of conventional chemotherapy while permitting enhanced selectivity to cancer cells. Targeted nanotheranostics permit targeted drug release, precise breast cancer diagnosis, and importantly, the ability to overcome MDR. The article discusses various nanomedicines designed to selectively target breast cancer, triple negative breast cancer, and breast cancer stem cells. In addition, the review discusses recent approaches, including combination nanoparticles (NPs), theranostic NPs, and stimuli sensitive or “smart” NPs. Recent innovations in microRNA NPs and personalized medicine NPs are also discussed. Future perspective research for complex targeted and multi-stage responsive nanomedicines for metastatic breast cancer is discussed.

pH-Responsive Lipid Nanocapsules: A Promising Strategy for Improved Resistant Melanoma Cell Internalization

Despite significant advances in melanoma therapy, low response rates and multidrug resistance (MDR) have been described, reducing the anticancer efficacy of the administered molecules. Among the causes to explain these resistances, the decreased intratumoral pH is known to potentiate MDR and to reduce the sensitivity to anticancer molecules. Nanomedicines have been widely exploited as the carriers of MDR reversing molecules. Lipid nanocapsules (LNC) are nanoparticles that have already demonstrated their ability to improve cancer treatment. Here, LNC were modified with novel copolymers that combine N-vinylpyrrolidone (NVP) to impart stealth properties and vinyl imidazole (Vim), providing pH-responsive ability to address classical chemoresistance by improving tumor cell entry. These copolymers could be post-inserted at the LNC surface, leading to the property of going from neutral charge under physiological pH to positive charge under acidic conditions. LNC modified with polymer P5 (C18H37-P(NVP21-co-Vim15)) showed in vitro pH-responsive properties characterized by an enhanced cellular uptake under acidic conditions. Moreover, P5 surface modification led to an increased biological effect by protecting the nanocarrier from opsonization by complement activation. These data suggest that pH-sensitive LNC responds to what is expected from a promising nanocarrier to target metastatic melanoma.

Comparative Analysis of Cell-Cell Contact Abundance in Ovarian Carcinoma Cells Cultured in Two- and Three-Dimensional In Vitro Models

Simple Summary

Tumor resistance to therapy is a crucial problem of today’s oncology. The emerging data indicate that tumor microenvironment is the key participant in the resistance development. One of the most basic aspect of tumor microenvironment is intercellular adhesion. Our data obtained using monolayer culture, matrix-free and matrix-based three-dimensional in vitro models indicate that the abundance of cell-cell contact proteins is varying depending on the microenvironment. These differences coincided with the degree of the resistance to therapeutics. The importance of adhesion proteins in tumor resistance may provide the fundamental basis for improving cancer treatment approaches and must be taken into account when screening candidate drugs.

Abstract

Tumor resistance to therapy is associated with the 3D organization and peculiarities of the tumor microenvironment, of which intercellular adhesion is a key participant. In this work, the abundance of contact proteins was compared in SKOV-3 and SKOV-3.ip human ovarian adenocarcinoma cell lines, cultivated in monolayers, tumor spheroids and collagen hydrogels. Three-dimensional models were characterized by extremely low expression of basic molecules of adherens junctions E-cadherin and demonstrated a simultaneous decrease in desmosomal protein desmoglein-2, gap junction protein connexin-43 and tight junction proteins occludin and ZO-1. The reduction in the level of contact proteins was most pronounced in collagen hydrogel, accompanied by significantly increased resistance to treatment with doxorubicin and targeted anticancer toxin DARPin-LoPE. Thus, we suggest that 3D models of ovarian cancer, especially matrix-based models, tend to recapitulate tumor microenvironment and treatment responsiveness to a greater extent than monolayer culture, so they can be used as a highly relevant platform for drug efficiency evaluation.

Hyperthermia Induced by Gold Nanoparticles and Visible Light Photothermy Combined with Chemotherapy to Tackle Doxorubicin Sensitive and Resistant Colorectal Tumor 3D Spheroids

Current cancer therapies are frequently ineffective and associated with severe side effects and with acquired cancer drug resistance. The development of effective therapies has been hampered by poor correlations between pre-clinical and clinical outcomes. Cancer cell-derived spheroids are three-dimensional (3D) structures that mimic layers of tumors in terms of oxygen and nutrient and drug resistance gradients. Gold nanoparticles (AuNP) are promising therapeutic agents which permit diminishing the emergence of secondary effects and increase therapeutic efficacy. In this work, 3D spheroids of Doxorubicin (Dox)-sensitive and -resistant colorectal carcinoma cell lines (HCT116 and HCT116-DoxR, respectively) were used to infer the potential of the combination of chemotherapy and Au-nanoparticle photothermy in the visible (green laser of 532 nm) to tackle drug resistance in cancer cells. Cell viability analysis of 3D tumor spheroids suggested that AuNPs induce cell death in the deeper layers of spheroids, further potentiated by laser irradiation. The penetration of Dox and earlier spheroid disaggregation is potentiated in combinatorial therapy with Dox, AuNP functionalized with polyethylene glycol (AuNP@PEG) and irradiation. The time point of Dox administration and irradiation showed to be important for spheroids destabilization. In HCT116-sensitive spheroids, pre-irradiation induced earlier disintegration of the 3D structure, while in HCT116 Dox-resistant spheroids, the loss of spheroid stability occurred almost instantly in post-irradiated spheroids, even with lower Dox concentrations. These results point towards the application of new strategies for cancer therapeutics, reducing side effects and resistance acquisition.

Sensitization of drug resistant sarcoma tumors by membrane modulation via short chain sphingolipid-containing nanoparticles

Nanoparticles such as liposomes are able to overcome cancer treatment challenges such as multidrug resistance by increasing the bioavailability of the encapsulated drug, bypassing drug pumps or through targeting resistant cells. Here, we merge enhanced drug delivery by nanotechnology with tumor cell membrane modulation combined in a single formulation. This is achieved through the incorporation of Short chain sphingolipids (SCSs) in the liposomal composition, which permeabilizes cell membranes to amphiphilic drugs such as Doxorubicin (Dxr). To study the mechanism and capability of SCS-containing nanodevices to overcome Dxr resistance, a sensitive uterine sarcoma cell line, MES-SA, and a resistant derived cell line, MES-SA/MX2, were used. The mechanism of resistance was explored by lipidomics and flow cytometry, revealing significant differences in lipid composition and in P glycoprotein (Pgp) expression. In vitro assays show that SCS liposomes were able to reverse cell resistance, and importantly, display a higher net effect on resistant than sensitive cells. SCS lipids modulated the cell membrane of MES-SA/MX2 drug resistant cells, while Pgp expression was not affected. Furthermore, SCS-modified liposomes were evaluated in a sarcoma xenograft model on drug accumulation, pharmacokinetics and efficacy. SCS liposomes improved Dxr levels in tumor nuclei of MES-SA/MX2 tumor cells, which was accompanied by a delay in tumor growth of the resistant model. Here we show that Dxr accumulation in tumor cells by SCS-modified liposomes was especially improved in Dxr resistant cells, rendering Dxr as effective as in sensitive cells. Moreover, this phenomenon translated to improved efficacy when Dxr liposomes where modified with SCSs in the drug resistant tumor model, while no benefit was seen in the sensitive tumors.

A novel targeted delivery system for drug-resistant hepatocellular carcinoma therapy

Hepatocellular carcinoma (HCC) is a severe malignant disease threatening human life. Current chemotherapy methods usually result in poor prognosis with low treatment efficacy and high side effects because of weak targeting specificity and fast acquisition of multidrug resistance (MDR). HCSP4 is a 12-aa peptide previously identified to specifically and sensitively bind to HCC cells and tissues. In this study, a novel class of HCC-targeting doxorubicin (DOX) delivery system, named HCSP4-Lipo-DOX-miR101, was synthesized and investigated for anticancer activity. HCSP4-Lipo-DOX-miR101 exhibited specific HCC targeting characteristics and satisfactory anticancer potency against HepG2 and HepG2/ADR cells, particularly HepG2/ADR cells. Moreover, the expression levels of genes closely related to membrane transport and cancer growth were significantly suppressed. This finding suggests that HCSP4-Lipo-DOX-miR101 can cause DOX-resistant HCC cell death and growth inhibition based on the targeting of MDR-related genes by miR-101. In conclusion, the findings of this study suggest that HCSP4-Lipo-DOX-miR101 may serve as a promising novel targeted delivery system for improving the therapeutic efficiency of drug-resistant hepatocellular carcinoma.

When polymers meet carbon nanostructures: expanding horizons in cancer therapy

The development of hybrid materials, which combine inorganic with organic materials, is receiving increasing attention by researchers. As a consequence of carbon nanostructures high chemical versatility, they exhibit enormous potential for new highly engineered multifunctional nanotherapeutic agents for cancer therapy. Whereas many groups are working on drug delivery systems for chemotherapy, the use of carbon nanohybrids for radiotherapy is rarely applied. Thus, nanotechnology offers a wide range of solutions to overcome the current obstacles of conventional chemo- and/or radiotherapies. Within this review, the structure and properties of carbon nanostructures (carbon nanotubes, nanographene oxide) functionalized preferentially with different types of polymers (synthetic, natural) are discussed. In short, synthesis approaches, toxicity investigations and anticancer efficacy of different carbon nanohybrids are described.

Nanotechnology as a Platform for the Development of Injectable Parenteral Formulations: A Comprehensive Review of the Know-Hows and State of the Art

Within recent decades, the development of nanotechnology has made a significant contribution to the progress of various fields of study, including the domains of medical and pharmaceutical sciences. A substantially transformed arena within the context of the latter is the development and production of various injectable parenteral formulations. Indeed, recent decades have witnessed a rapid growth of the marketed and pipeline nanotechnology-based injectable products, which is a testimony to the remarkability of the aforementioned contribution. Adjunct to the ability of nanomaterials to deliver the incorporated payloads to many different targets of interest, nanotechnology has substantially assisted to the development of many further facets of the art. Such contributions include the enhancement of the drug solubility, development of long-acting locally and systemically injectable formulations, tuning the onset of the drug’s release through the endowment of sensitivity to various internal or external stimuli, as well as adjuvancy and immune activation, which is a desirable component for injectable vaccines and immunotherapeutic formulations. The current work seeks to provide a comprehensive review of all the abovementioned contributions, along with the most recent advances made within each domain. Furthermore, recent developments within the domains of passive and active targeting will be briefly debated.

Functionalized Carbon Nanostructures Versus Drug Resistance: Promising Scenarios in Cancer Treatment

Carbon nanostructures (CN) are emerging valuable materials for the assembly of highly engineered multifunctional nanovehicles for cancer therapy, in particular for counteracting the insurgence of multi-drug resistance (MDR). In this regard, carbon nanotubes (CNT), graphene oxide (GO), and fullerenes (F) have been proposed as promising materials due to their superior physical, chemical, and biological features. The possibility to easily modify their surface, conferring tailored properties, allows different CN derivatives to be synthesized. Although many studies have explored this topic, a comprehensive review evaluating the beneficial use of functionalized CNT vs G or F is still missing. Within this paper, the most relevant examples of CN-based nanosystems proposed for MDR reversal are reviewed, taking into consideration the functionalization routes, as well as the biological mechanisms involved and the possible toxicity concerns. The main aim is to understand which functional CN represents the most promising strategy to be further investigated for overcoming MDR in cancer.

Engineered Polymeric Materials for Biological Applications: Overcoming Challenges of the Bio-Nano Interface

Nanomedicine has generated significant interest as an alternative to conventional cancertherapy due to the ability for nanoparticles to tune cargo release. However, while nanoparticletechnology has promised significant benefit, there are still limited examples of nanoparticles inclinical practice. The low translational success of nanoparticle research is due to the series ofbiological roadblocks that nanoparticles must migrate to be effective, including blood and plasmainteractions, clearance, extravasation, and tumor penetration, through to cellular targeting,internalization, and endosomal escape. It is important to consider these roadblocks holistically inorder to design more effective delivery systems. This perspective will discuss how nanoparticlescan be designed to migrate each of these biological challenges and thus improve nanoparticledelivery systems in the future. In this review, we have limited the literature discussed to studiesinvestigating the impact of polymer nanoparticle structure or composition on therapeutic deliveryand associated advancements. The focus of this review is to highlight the impact of nanoparticlecharacteristics on the interaction with different biological barriers. More specific studies/reviewshave been referenced where possible.

Synthesis and antitumor activity of novel pyridinium fullerene derivatives

Purpose

We have previously reported that some cationic fullerene derivatives exhibited anticancer activity, and they are expected to be a potential lead compound for an anti-drug resistant cancer agent. However, they are bis-adducts and a mixture of multiple regioisomers, which cannot be readily separated due to the variability of substituent positions on the fullerene cage. To overcome this issue, we evaluated the antiproliferative activities of a set of mono-adduct derivatives and examined their structure-activity relationship. In addition, the in vivo antitumor activity of selected derivatives was also examined.

Methods

Nineteen pyridinium fullerene derivatives were newly designed and synthesized in this study. Their antiproliferative activities were evaluated using several cancer cell lines including drug-resistant cells. Furthermore, in vivo antitumor activity of several derivatives was investigated in mouse xenograft model of human lung cancer.

Results

The derivatives inhibited the proliferation of cancer cell lines, including cisplatin-resistant cells and doxorubicin-resistant cells. It was also shown that compound 10 (10 μM), 13 (10 μM) and cis-14 (10 μM) induced the intracellular oxidative stress. In addition, compound 13 (20 mg/kg) and cis-14 (15 mg/kg) significantly exhibited antitumor activity in mouse xenograft model of human lung cancer.

Conclusion

We synthesized a novel set of mono-adduct fullerene derivatives functionalized with pyridinium groups and found that most of them show potent antiproliferative activities against cancer cell lines and some of them show significant antitumor activities in vivo. We propose that these fullerene derivatives serve as the lead compounds for a novel type of antitumor agents.

Rising horizon in circumventing multidrug resistance in chemotherapy with nanotechnology

Multidrug resistance (MDR) is one of the key barriers in chemotherapy, leading to the generation of insensitive cancer cells towards administered therapy. Genetic and epigenetic alterations of the cells are the consequences of MDR, resulted in drug resistivity, which reflects in impaired delivery of cytotoxic agents to the cancer site. Nanotechnology-based nanocarriers have shown immense shreds of evidence in overcoming these problems, where these promising tools handle desired dosage load of hydrophobic chemotherapeutics to facilitate designing of safe, controlled and effective delivery to specifically at tumor microenvironment. Therefore, encapsulating drugs within the nano-architecture have shown to enhance solubility, bioavailability, drug targeting, where co-administered P-gp inhibitors have additionally combat against developed MDR. Moreover, recent advancement in the stimuli-sensitive delivery of nanocarriers facilitates a tumor-targeted release of the chemotherapeutics to reduce the associated toxicities of chemotherapeutic agents in normal cells. The present article is focused on MDR development strategies in the cancer cell and different nanocarrier-based approaches in circumventing this hurdle to establish an effective therapy against deadliest cancer disease.

Challenges and Opportunities from Basic Cancer Biology for Nanomedicine for Targeted Drug Delivery

Background:

Effective cancer therapy is still a great challenge for modern medical research due to the complex underlying mechanisms of tumorigenesis and tumor metastasis, and the limitations commonly associated with currently used cancer therapeutic options. Nanotechnology has been implemented in cancer therapeutics with immense potential for improving cancer treatment.

Objective:

Through information about the recent advances regarding cancer hallmarks, we could comprehensively understand the pharmacological effects and explore the mechanisms of the interaction between the nanomaterials, which could provide opportunities to develop mechanism-based nanomedicine to treat human cancers.

Methods:

We collected related information and data from articles.

Results:

In this review, we discussed the characteristics of cancer including tumor angiogenesis, abnormalities in tumor blood vessels, uncontrolled cell proliferation markers, multidrug resistance, tumor metastasis, cancer cell metabolism, and tumor immune system that provide opportunities and challenges for nanomedicine to be directed to specific cancer cells and portray the progress that has been accomplished in application of nanotechnology for cancer treatment.

Conclusion:

The information presented in this review can provide useful references for further studies on developing effective nanomedicine for the treatment of cancer.

Enhanced anticancer activity and intracellular uptake of paclitaxel-containing solid lipid nanoparticles in multidrug-resistant breast cancer cells

PURPOSE

The aim of this study was to show enhanced anticancer activity of paclitaxel (Ptx) incorporated into solid lipid nanoparticles (SLNs) and reveal reversal of multidrug resistance (MDR) by SLNs mediated by increased uptake through different entry mechanisms from that in drug-sensitive cells.

METHODS

Anticancer activity of Ptx incorporated in SLNs (Ptx-SLNs) was measured in the drug-sensitive human breast cancer cell line MCF7 and its MDR variant MCF7/ADR. Cellular uptake of cargo molecules in SLNs was compared using Ptx-SLNs and rhodamine 123-loaded SLNs (Rho-SLNs) in both cell lines. In addition, endocytic uptake was evaluated using genistein (Gen) and chlorpromazine (Cpz) as inhibitors of clathrin- and caveola-mediated endocytosis, respectively.

RESULTS

Ptx-SLNs showed remarkably enhanced anticancer activity in MCF7/ADR compared to Ptx delivered in dimethyl sulfoxide (DMSO) and Cremophor EL-based vehicles. SLNs significantly increased intracellular uptake of Ptx and Rho in MCF7/ADR. Western blotting demonstrated that clathrin was expressed in both cell lines, while caveolin 1 was expressed only in MCF7/ADR. In MCF7/ADR, uptake of Ptx-SLNs and Rho-SLNs was reduced by Gen, while there was no change by Cpz, suggesting the involvement of caveola-mediated endocytosis. Size reduction of Rho-SLNs through high-pressure homogenization (Rho-SLNs) appeared to cause a shift of the endocytosis mechanism from a clathrin-independent pathway to a clathrin-dependent one. In contrast to MCF7/ADR, the uptake of SLNs into MCF7 was not changed by Gen or Cpz, suggesting involvement of clathrin- and caveola-independent mechanism for the entry of SLNs.

CONCLUSION

MDR was reversed by incorporating drug into SLNs, and the reversal was mediated by increased uptake of SLNs evading efflux pumps in MDR cells. The enhanced uptake could also be due to the use of different endocytosis pathways by SLNs in MDR cells from drug-sensitive cancer cells.

Arminin 1a-C, a novel antimicrobial peptide from ancient metazoan Hydra, shows potent antileukemia activity against drug-sensitive and drug-resistant leukemia cells

Purpose

Due to the emergence of multidrug resistance (MDR), traditional antileukemia drugs no longer meet the treatment needs. Therefore, new antileukemia drugs with different action mechanisms are urgently needed to cope with this situation.

Materials and methods

Arminin 1a-C is an antimicrobial peptide (AMP) developed from the ancient metazoan marine Hydra. In this study, we first explored its antileukemia activity.

Results

Our results showed that Arminin 1a-C formed an α-helical structure and efficaciously suppressed the viability of leukemia cell lines whether or not they were multidrug resistant or sensitive, and there were no obvious differences between these cell lines. Arminin 1a-C exhibited distinct selectivity between noncancerous and cancerous cell lines. Arminin 1a-C interfered with K562/adriamycin (ADM) cell (a kind of multidrug-resistant leukemia cell line) proliferation in a very rapid manner and formed pores in its cell membrane, making it difficult to develop resistance against Arminin 1a-C.

Conclusion

Our data show that Arminin 1a-C possesses great potential as a therapeutic candidate for the treatment of multidrug-resistant leukemia.

Glioma Cell Secretion: A Driver of Tumor Progression and a Potential Therapeutic Target

Cellular secretion is an important mediator of cancer progression. Secreted molecules in glioma are key components of complex autocrine and paracrine pathways that mediate multiple oncogenic pathologies. In this review, we describe tumor cell secretion in high-grade glioma and highlight potential novel therapeutic opportunities. Cancer Res; 78(21); 6031-9. ©2018 AACR.

Biodegradable nanoparticles bearing amine groups as a strategy to alter surface features, biological identity and accumulation in a lung metastasis model

Polymer-based nanoparticles (NPs) with a cationic charge have emerged recently as a potent nanotool due to their unique ability to penetrate deeply inside tumor tissue and to interact preferentially with the plasma membrane of cancer cells. In this paper, we propose a general strategy to obtain biodegradable cationic NPs of poly(ε-caprolactone) (PCL) based on an amine terminated PCL (NH₂-PCL_4.2k) or its mixture with monomethoxypoly(ethylene glycol)-PCL (mPEG_1k-PCL_4k). Positively-charged NPs were obtained, switching to net negative values through adsorption of low molecular weight hyaluronan. NPs exposing both amine and PEG groups on the surface showed a larger fixed aqueous layer thickness as compared to fully PEGylated NPs, suggesting that PEG conformation/localization is affected by the presence of amino groups. The stability of the positively-charged NPs was affected by the presence of ions, while interaction with the human plasma protein pool indicated time-dependent protein corona formation imparting an overall negative charge. NP-induced haemolysis was low, while cytotoxicity against A549 and Calu-3 lung cancer cell lines was cell-specific as well as dose and time-dependent. Finally, the presence of amino groups greatly changed the in vivo biodistribution of the NPs in tumor-bearing mice (lung colonization of B16F10 cancer cells) allowing the amine/PEGylated NPs to accumulate mainly at the target organ. Overall, this study demonstrates that NPs with a mixed amine/PEGylated surface exhibit a peculiar biological identity that alters their interaction with the bioenvironment and are thus worthy of further investigation in the delivery of chemotherapeutics.

P-glycoprotein targeted and near-infrared light-guided depletion of chemoresistant tumors

Drug resistance remains a formidable challenge to cancer therapy. P-glycoprotein (Pgp) contributes to multidrug resistance in numerous cancers by preventing accumulation of anticancer drugs in cancer cells. Strategies to overcome this resistance have been vigorously sought for over 3 decades, yet clinical solutions do not exist. The main reason for the failure is lack of cancer specificity of small-molecule Pgp inhibitors, thus causing severe toxicity in normal tissues. In this study, Pgp-targeted photodynamic therapy (PDT) was developed to achieve superior cancer specificity through antibody targeting plus locoregional light activation. Thus, a Pgp monoclonal antibody was chemically modified with IR700, a porphyrin photosensitizer. In vitro studies showed that the antibody-photosensitizer conjugates specifically bind to Pgp-expressing drug resistant cancer cells, and caused dramatic cytotoxicity upon irradiation with a near infrared light. We then tested our Pgp-targeted approach in mouse xenograft models of chemoresistant ovarian cancer and head and neck cancer. In both models, targeted PDT produced rapid tumor shrinkage, and significantly prolonged survival of tumor-bearing mice. We conclude that our targeted PDT approach produces molecularly targeted and spatially selective ablation of chemoresistant tumors, and thereby provides an effective approach to overcome Pgp-mediated multidrug resistance in cancer, where conventional approaches have failed.

Mitochondria-targeted delivery of doxorubicin to enhance antitumor activity with HER-2 peptide-mediated multifunctional pH-sensitive DQAsomes

Introduction

Multidrug resistance (MDR) of breast cancer is the major challenge to successful chemotherapy while mitochondria-targeting therapy was a promising strategy to overcome MDR.

Materials and methods

In this study, HER-2 peptide-PEG₂₀₀₀-Schiff base-cholesterol (HPSC) derivate was synthesized successfully and incorporated it on the surface of the doxorubicin (DOX)-loaded dequalinium (DQA) chloride vesicle (HPS-DQAsomes) to treat drug-resistant breast cancer. Evaluations were performed using human breast cancer cell and DOX-resistant breast cancer cell lines (MCF-7 and MCF-7/ADR).

Results

The particle size of HPS-DQAsomes was ~110 nm with spherical shape. In vitro cytotoxicity assay indicated that HPS-DQAsomes could increase the cytotoxicity against MCF-7/ADR cell line. Cellular uptake and mitochondria-targeting assay demonstrated that HPS-DQAsomes could target delivering therapeutical agent to mitochondria and inducing mitochondria-driven apoptosis process. In vivo antitumor assay suggested that HPS-DQAsomes could reach favorable antitumor activity due to both tumor targetability and sub-organelles’ targetability. Histological assay also indicated that HPS-DQAsomes showed a strong apoptosis-inducing effect. No obvious systematic toxicity of HPS-DQAsomes could be observed.

Conclusion

In summary, multifunctional HPS-DQAsomes provide a novel and versatile approach for overcoming MDR via mitochondrial pathway in cancer treatment.

NK-18, a promising antimicrobial peptide: anti-multidrug resistant leukemia cells and LPS neutralizing properties

With the increase of multidrug resistance, novel anti-leukemia agents with diverse mechanisms of action are required to address this challenge. NK-18, the core region of mammalian derived protein NK-lysin, effectively inhibited the viability of both multidrug resistant and sensitive leukemia cell lines. Meanwhile, this proliferation inhibition effect was not distinct between sensitive and multidrug resistant leukemia cell line. NK-18 showed selectivity between non-tumorigenic and tumorigenic cells. It preferentially bound to tumor cells whose outer leaflet with high phosphatidylserine content. NK-18 acted on the multidrug resistant leukemia cell line by a rapid pore formation on the cell membrane, it is not easy for K562/ADM cells developing resistance against NK-18. Furthermore, NK-18 could neutralize lipopolysaccharides by electrostatic attraction and reduce NO production. These research data demonstrated NK-18 possesses great advantage in the multidrug resistant leukemia treatment compared with conventional chemotherapies and it could be a potential candidate for further research.