Novel nanomedicines to overcome cancer multidrug resistance

Acceptor-donor-acceptor type organic photothermal agents with enhanced NIR absorption and photothermal conversion effect for cancer photothermal therapy

Numerous photothermal agents (PTAs) require high-intensity and long-duration laser excitation for photothermal therapy (PTT), resulting in light damage to healthy skin and tissue as well as limiting their biomedical applications. Integrating desirable near-infrared (NIR) absorption and high photothermal conversion efficiency (PCE) into a single small-molecule PTA is an important prerequisite for realizing efficient PTT, but is a serious challenge. Herein, through molecular engineering strategy, an acceptor-donor-acceptor (A-D-A) type PTA (ADA3) was readily developed for 808 nm laser-driving photothermal imaging and PTT of tumor. Theoretical calculations and experiment results show molecular engineering strategy is significant in regulating the structure and energy gap of PTAs, so as to effectively induce a narrow band gap for NIR absorption and further optimize photothermal properties. ADA3 possesses molar extinction coefficient of 3.1 × 104 M-1 cm-1 at 808 nm, followed being assembled into nanoparticles, ADA3-NPs show high PCE of 80.3%. In vivo experiments indicate that ADA3-NPs have excellent antitumor capability under one-time, low-intensity and short-duration (808 nm, 330 mW/cm2, 3 min) laser irradiation. Therefore, this work definitely exemplifies the enormous potential of molecular engineering strategy and provides an effective method for developing small-molecule PTAs.

Carrier capability of halloysite nanotubes for the intracellular delivery of antisense PNA targeting mRNA of neuroglobin gene

Peptide nucleic acid (PNA) is a DNA mimic that shows good stability against nucleases and proteases, forming strongly recognized complementary strands of DNA and RNA. However, due to its feeble ability to cross the cellular membrane, PNA activity and its targeting gene action is limited. Halloysite nanotubes (HNTs) are a natural and low-cost aluminosilicate clay. Because of their peculiar ability to cross cellular membrane, HNTs represent a valuable candidate for delivering genetic materials into cells. Herein, two differently charged 12-mer PNAs capable of recognizing as molecular target a 12-mer DNA molecule mimicking a purine-rich tract of neuroglobin were synthetized and loaded onto HNTs by electrostatic attraction interactions. After characterization, the kinetic release was also assessed in media mimicking physiological conditions. Resonance light scattering measurements assessed their ability to bind complementary single-stranded DNA. Furthermore, their intracellular delivery was assessed by confocal laser scanning microscopy on living MCF-7 cells incubated with fluorescence isothiocyanate (FITC)-PNA and HNTs labeled with a probe. The nanomaterials were found to cross cellular membrane and cell nuclei efficiently. Finally, it is worth mentioning that the HNTs/PNA can reduce the level of neuroglobin gene expression, as shown by reverse transcription-quantitative polymerase chain reaction and western blotting analysis.

Targeting anoikis resistance as a strategy for cancer therapy

Anoikis, known as matrix detachment-induced apoptosis or detachment-induced cell death, is crucial for tissue development and homeostasis. Cancer cells develop means to evade anoikis, e.g. anoikis resistance, thereby allowing for cells to survive under anchorage-independent conditions. Uncovering the mechanisms of anoikis resistance will provide details about cancer metastasis, and potential strategies against cancer cell dissemination and metastasis. Here, we summarize the principal elements and core molecular mechanisms of anoikis and anoikis resistance. We discuss the latest progress of how anoikis and anoikis resistance are regulated in cancers. Furthermore, we summarize emerging data on selective compounds and nanomedicines, explaining how inhibiting anoikis resistance can serve as a meaningful treatment modality against cancers. Finally, we discuss the key limitations of this therapeutic paradigm and possible strategies to overcome them. In this review, we suggest that pharmacological modulation of anoikis and anoikis resistance by bioactive compounds could surmount anoikis resistance, highlighting a promising therapeutic regimen that could be used to overcome anoikis resistance in cancers.

Photodynamically Tumor Vessel Destruction Amplified Tumor Targeting of Nanoparticles for Efficient Chemotherapy

Efficient tumor-targeted drug delivery is still a challenging and currently unbreakable bottleneck in chemotherapy for tumors. Nanomedicines based on passive or active targeting strategy have not yet achieved convincing chemotherapeutic benefits in the clinic due to the tumor heterogeneity. Inspired by the efficient inflammatory-cell recruitment to acute clots, we constructed a two-component nanosystem, which is composed of an RGD-modified pyropheophorbide-a (Ppa) micelle (PPRM) that mediates the tumor vascular-targeted photodynamic reaction to activate local coagulation and subsequently transmits the coagulation signals to the circulating clot-targeted CREKA peptide-modified camptothecin (CPT)-loaded nanodiscs (CCNDs) for amplifying tumor targeting. PPRM could effectively bind with the tumor vasculature and induce sufficient local thrombus by a photodynamic reaction. Local photodynamic reaction-induced tumor target amplification greatly increased the tumor accumulation of CCND by 4.2 times, thus significantly enhancing the chemotherapeutic efficacy in the 4T1 breast tumor model. In other words, this study provides a powerful platform to amplify tumor-specific drug delivery by taking advantage of the efficient crosstalk between the PPRM-activated coagulation cascade and clot-targeted CCND.

de Oliveira A, Pascoal ACRF, Cruz AL, Nascimento V. New Chalcogen-Functionalized Naphthoquinones: Design, Synthesis, and Evaluation, In Vitro and In Silico, against Squamous Cell Carcinoma

Due to the growth in the number of patients and the complexity involved in anticancer therapies, new therapeutic approaches are urgent and necessary. In this context, compounds containing the selenium atom can be employed in developing new medicines due to their potential therapeutic efficacy and unique modes of action. Furthermore, tellurium, a previously unknown element, has emerged as a promising possibility in chalcogen-containing compounds. In this study, 13 target compounds (9a-i, 10a-c, and 11) were effectively synthesized as potential anticancer agents, employing a CuI-catalyzed Csp-chalcogen bond formation procedure. The developed methodology yielded excellent results, ranging from 30 to 85%, and the compounds were carefully characterized. Eight of these compounds showed promise as potential therapeutic drugs due to their high yields and remarkable selectivity against SCC-9 cells (squamous cell carcinoma). Compound 10a, in particular, demonstrated exceptional selectivity, making it an excellent choice for cancer cell targeting while sparing healthy cells. Furthermore, complementing in silico and molecular docking studies shed light on their physical features and putative modes of action. This research highlights the potential of these compounds in anticancer treatments and lays the way for future drug development efforts.

Lenvatinib in hepatocellular carcinoma: Resistance mechanisms and strategies for improved efficacy

Hepatocellular carcinoma (HCC), one of the most prevalent and destructive causes of cancer-related deaths worldwide, approximately 70% of patients with HCC exhibit advanced disease at diagnosis, limiting the potential for radical treatment. For such patients, lenvatinib, a long-awaited alternative to sorafenib for first-line targeted therapy, has become a key treatment. Unfortunately, despite some progress, the prognosis for advanced HCC remains poor because of drug resistance development. However, the molecular mechanisms underlying lenvatinib resistance and ways to relief drug resistance in HCC are largely unknown and lack of systematic summary; thus, this review not only aims to explore factors contributing to lenvatinib resistance in HCC, but more importantly, summary potential methods to conquer or mitigate the resistance. The results suggest that abnormal activation of pathways, drug transport, epigenetics, tumour microenvironment, cancer stem cells, regulated cell death, epithelial-mesenchymal transition, and other mechanisms are involved in the development of lenvatinib resistance in HCC and subsequent HCC progression. To improve the therapeutic outcomes of lenvatinib, inhibiting acquired resistance, combined therapies, and nano-delivery carriers may be possible approaches.

Co-Delivery of siNRF2 and Sorafenib by a "Click" Dual Functioned Hyperbranched Nanocarrier for Synergistically Inducing Ferroptosis in Hepatocellular Carcinoma

In the course of antitumor therapy, the complex tumor microenvironment and drug-mediated changes in cell signaling and biological processes lead to drug resistance. The effect of sorafenib is greatly limited by the specific tumor microenvironment induced by antiangiogenic therapy and ferroptosis resistance induced by the upregulation of nuclear factor erythroid-2 related factor 2 (NRF2). In this study, a pH responsive and amphiphilic hyperbranched polyglycerol, HDP, is synthesized based on a co-graft click chemistry pathway. This nano-scale carrier provides excellent drug-loading capacity, storing stability and pH responsibility, and effectively co-delivery of sorafenib and siRNA. Sorafenib and siNRF2 plays a greatly synergistic effect in inducing reactive oxygen species (ROS), iron overloading, depleting glutathione (GSH), and promoting lipid peroxidation. Importantly, verified in two different animal experiments, HDP-ss (HDP loaded with both siNRF2 and sorafenib) presents a superior anti-tumor effect, by achieving a tumor inhibition rate of ≈94%. Thus, HDP can serve as an excellent targeted delivery nanocarrier with good biocompatibility in antitumor therapy, and combined application of siNRF2 effectively improves the antitumor effect of sorafenib by overcoming NRF2-mediated ferroptosis resistance. Taken together, this study provides a novel therapeutic strategy to combat the drug resistance in antiangiogenic therapy and ferroptosis.

Nanotherapeutics for prostate cancer treatment: A comprehensive review

Prostate cancer (PCa) is the most prevalent solid organ malignancy and seriously affects male health. The adverse effects of prostate cancer therapeutics can cause secondary damage to patients. Nanotherapeutics, which have special targeting abilities and controlled therapeutic release profiles, may serve as alternative agents for PCa treatment. At present, many nanotherapeutics have been developed to treat PCa and have shown better treatment effects in animals than traditional therapeutics. Although PCa nanotherapeutics are highly attractive, few successful cases have been reported in clinical practice. To help researchers design valuable nanotherapeutics for PCa treatment and avoid useless efforts, herein, we first reviewed the strategies and challenges involved in prostate cancer treatment. Subsequently, we presented a comprehensive review of nanotherapeutics for PCa treatment, including their targeting methods, controlled release strategies, therapeutic approaches and mechanisms. Finally, we proposed the future prospects of nanotherapeutics for PCa treatment.

Targeted cancer treatment using folate-conjugated sponge-like ZIF-8 nanoparticles: a review

ZIF-8 (zeolitic imidazolate framework-8) is a potential drug delivery system because of its unique properties, which include a large surface area, a large pore capacity, a large loading capacity, and outstanding stability under physiological conditions. ZIF-8 nanoparticles may be readily functionalized with targeting ligands for the identification and absorption of particular cancer cells, enhancing the efficacy of chemotherapeutic medicines and reducing adverse effects. ZIF-8 is also pH-responsive, allowing medication release in the acidic milieu of cancer cells. Because of its tunable structure, it can be easily functionalized to design cancer-specific targeted medicines. The delivery of ZIF-8 to cancer cells can be facilitated by folic acid-conjugation. Hence, it can bind to overexpressed folate receptors on the surface of cancer cells, which holds the promise of reducing unwanted deliveries. As a result of its importance in cancer treatment, the folate-conjugated ZIF-8 was the major focus of this review.

The role of histone H1.2 in pancreatic cancer metastasis and chemoresistance

AIMS

Pancreatic cancer (PC) is a highly metastatic malignant tumor of the digestive system. Drug resistance frequently occurs during cancer treatment process. This study aimed to explore the link between chemoresistance and tumor metastasis in PC and its possible molecular and cellular mechanisms.

METHODS

A Metastasis and Chemoresistance Signature (MCS) scoring system was built and validated based on metastasis- and chemoresistance-related genes using gene expression data of PC, and the model was applied to single-cell RNA sequencing data. The influence of linker histone H1.2 (H1-2) on PC was explored through in vitro and in vivo experiments including proliferation, invasion, migration, drug sensitivity, rescue experiments and immunohistochemistry, emphasizing its regulation with c-MYC signaling pathway.

RESULTS

A novel MCS scoring system accurately predicted PC patient survival and was linked to chemoresistance and epithelial-mesenchymal transition (EMT) in PC single-cell RNA sequencing data. H1-2 emerged as a significant prognostic factor, with its high expression indicating increased chemoresistance and EMT. This upregulation was mediated by c-MYC, which was also found to be highly expressed in PC tissues.

CONCLUSION

The MCS scoring system offers insights into PC chemoresistance and metastasis potential. Targeting H1-2 could enhance therapeutic strategies and improve PC patient outcomes.

Recent Advances in Photothermal Therapy at Near-Infrared-II Based on 2D MXenes

The use of photothermal therapy (PTT) with the near-infrared II region (NIR-II: 1000-1700 nm) is expected to be a powerful cancer treatment strategy. It retains the noninvasive nature and excellent temporal and spatial controllability of the traditional PTT, and offers significant advantages in terms of tissue penetration depth, background noise, and the maximum permissible exposure standards for skin. MXenes, transition-metal carbides, nitrides, and carbonitrides are emerging inorganic nanomaterials with natural biocompatibility, wide spectral absorption, and a high photothermal conversion efficiency. The PTT of MXenes in the NIR-II region not only provides a valuable reference for exploring photothermal agents that respond to NIR-II in 2D inorganic nanomaterials, but also be considered as a promising biomedical therapy. First, the synthesis methods of 2D MXenes are briefly summarized, and the laser light source, mechanism of photothermal conversion, and evaluation criteria of photothermal performance are introduced. Second, the latest progress of PTT based on 2D MXenes in NIR-II are reviewed, including titanium carbide (Ti3 C2 ), niobium carbide (Nb2 C), and molybdenum carbide (Mo2 C). Finally, the main problems in the PTT application of 2D MXenes to NIR-II and future research directions are discussed.

Direct K-Ras Inhibitors to Treat Cancers: Progress, New Insights, and Approaches to Treat Resistance

Here we discuss approaches to K-Ras inhibition and drug resistance scenarios. A breakthrough offered a covalent drug against K-RasG12C. Subsequent innovations harnessed same-allele drug combinations, as well as cotargeting K-RasG12C with a companion drug to upstream regulators or downstream kinases. However, primary, adaptive, and acquired resistance inevitably emerge. The preexisting mutation load can explain how even exceedingly rare mutations with unobservable effects can promote drug resistance, seeding growth of insensitive cell clones, and proliferation. Statistics confirm the expectation that most resistance-related mutations are in cis, pointing to the high probability of cooperative, same-allele effects. In addition to targeted Ras inhibitors and drug combinations, bifunctional molecules and innovative tri-complex inhibitors to target Ras mutants are also under development. Since the identities and potential contributions of preexisting and evolving mutations are unknown, selecting a pharmacologic combination is taxing. Collectively, our broad review outlines considerations and provides new insights into pharmacology and resistance.

A review of chitosan in gene therapy: Developments and challenges

Gene therapy, as a revolutionary treatment, has been gaining more and more attention. The key to gene therapy is the selection of suitable vectors for protection of exogenous nucleic acid molecules and enabling their specific release in target cells. While viral vectors have been widely used in researches, non-viral vectors are receiving more attention due to its advantages. Chitosan (CS) has been widely used as non-viral organic gene carrier because of its good biocompatibility and its ability to load large amounts of nucleic acids. This paper summarizes and evaluates the potential of chitosan and its derivatives as gene delivery vector materials, along with factors influencing transfection efficiency, performance evaluation, ways to optimize infectious efficiency, and the current main research development directions. Additionally, it provides an outlook on its future prospects.

Intracellular self-aggregation of biomimetic Fe3O4 nanoparticles for enhanced ferroptosis-inducing therapy of breast cancer

Nanomedicines based on ferroptosis may be effective strategies for cancer therapy due to their unique inducing mechanism. However, the challenges, including non-target distribution, poor accumulation and retention of nanomedicine, have a profound impact on the effectiveness of drug delivery. Here, we developed cancer cell membrane (CCM)-coated Fe3O4 nanoparticles (NPs) modified with supramolecular precursors and loaded with sulfasalazine (SAS) for breast cancer therapy. Benefiting from the coating of the CCM, these NPs can be specifically recognized and internalized by tumor cells rapidly after being administered and form aggregates via the host-guest interaction between adamantane (ADA) and cyclodextrins (CD), which in turn effectively reduces the exocytosis of tumor cells and prolongs the retention time. In vitro and in vivo studies showed that Fe3O4 NPs possessed effective cellular uptake and precise specific accumulation in tumor cells and tissues through CCM-targeted supramolecular in situ aggregation, demonstrating enhanced ferroptosis-inducing therapy of breast cancer. Overall, this work provided a supramolecular biomimetic platform to achieve targeted delivery of Fe3O4 NPs with high efficiency and precise self-assembly for improved cancer therapy.

Nanodelivery Systems as a Novel Strategy to Overcome Treatment Failure of Cancer

Despite the tremendous progress in cancer treatment in recent decades, cancers often become resistant due to multiple mechanisms, such as intrinsic or acquired multidrug resistance, which leads to unsatisfactory treatment effects or accompanying metastasis and recurrence, ultimately to treatment failure. With a deeper understanding of the molecular mechanisms of tumors, researchers have realized that treatment designs targeting tumor resistance mechanisms would be a promising strategy to break the therapeutic deadlock. Nanodelivery systems have excellent physicochemical properties, including highly efficient tissue-specific delivery, substantial specific surface area, and controllable surface chemistry, which endow nanodelivery systems with capabilities such as precise targeting, deep penetration, responsive drug release, multidrug codelivery, and multimodal synergy, which are currently widely used in biomedical researches and bring a new dawn for overcoming cancer resistance. Based on the mechanisms of tumor therapeutic resistance, this review summarizes the research progress of nanodelivery systems for overcoming tumor resistance to improve therapeutic efficacy in recent years and offers prospects and challenges of the application of nanodelivery systems for overcoming cancer resistance.

Nanomedicine Combats Drug Resistance in Lung Cancer

Lung cancer is the second most prevalent cancer and the leading cause of cancer-related death worldwide. Surgery, chemotherapy, molecular targeted therapy, immunotherapy, and radiotherapy are currently available as treatment methods. However, drug resistance is a significant factor in the failure of lung cancer treatments. Novel therapeutics have been exploited to address complicated resistance mechanisms of lung cancer and the advancement of nanomedicine is extremely promising in terms of overcoming drug resistance. Nanomedicine equipped with multifunctional and tunable physiochemical properties in alignment with tumor genetic profiles can achieve precise, safe, and effective treatment while minimizing or eradicating drug resistance in cancer. Here, this work reviews the discovered resistance mechanisms for lung cancer chemotherapy, molecular targeted therapy, immunotherapy, and radiotherapy, and outlines novel strategies for the development of nanomedicine against drug resistance. This work focuses on engineering design, customized delivery, current challenges, and clinical translation of nanomedicine in the application of resistant lung cancer.

Multifunctional nano MOF drug delivery platform in combination therapy

Recent preclinical and clinical studies have demonstrated that for cancer treatment, combination therapies are more effective than monotherapies in reducing drug-related toxicity, decreasing drug resistance, and improving therapeutic efficacy. With the rapid development of nanotechnology, the combination of metal-organic frameworks (MOFs) and multi-mode therapy offers a realistic possibility to further improve the shortcomings of cancer treatment. This article focuses on the latest developments, achievements, and treatment strategies of representative multifunctional MOF combination therapies for cancer treatment in recent years, which include not only bimodal combination therapies, but also multi-modal synergistic therapies, further demonstrating the effectiveness and superiority of the MOF drug delivery systems in cancer treatment.

Recent advances of polymeric nanoplatforms for cancer treatment: smart delivery systems (SDS), nanotheranostics and multidrug resistance (MDR) inhibition

Nanotheranostics is a promising field that combines the benefits of diagnostic and treatment into a single nano-platform that not only administers treatment but also allows for real-time monitoring of therapeutic response, decreasing the possibility of under/over-drug dosing. Furthermore, developing smart delivery systems (SDSs) for cancer theranostics that can take advantage of various tumour microenvironment (TME) conditions (such as deformed tumour vasculature, various over-expressed receptor proteins, reduced pH, oxidative stress, and resulting elevated glutathione levels) can aid in achieving improved pharmacokinetics, higher tumour accumulation, enhanced antitumour efficacy, and/or decreased side effects and multidrug resistance (MDR) inhibition. Polymeric nanoparticles (PNPs) are being widely investigated in this regard due to their unique features such as small size, passive/active targeting possibility, better pharmaceutical kinetics and biological distribution, decreased adverse reactions of the established drugs, inherent inhibitory properties to MDR efflux pump proteins, as well as the feasibility of delivering numerous therapeutic substances in just one design. Hence in this review, we have primarily discussed PNPs based targeted and/or controlled SDSs in which we have elaborated upon different TME mediated nanotheranostic platforms (NTPs) including active/passive/magnetic targeting platforms along with pH/ROS/redox-responsive platforms. Besides, we have elucidated different imaging guided cancer therapeutic platforms based on four major cancer imaging techniques i.e., fluorescence/photo-acoustic/radionuclide/magnetic resonance imaging, Furthermore, we have deliberated some of the most recently developed PNPs based multimodal NTPs (by combining two or more imaging or therapy techniques on a single nanoplatform) in cancer theranostics. Moreover, we have provided a brief update on PNPs based NTP which are recently developed to overcome MDR for effective cancer treatment. Additionally, we have briefly discussed about the tissue biodistribution/tumour targeting efficiency of these nanoplatforms along with recent preclinical/clinical studies. Finally, we have elaborated on various limitations associated with PNPs based nanoplatforms.

Supramolecular host-guest nanosystems for overcoming cancer drug resistance

Cancer drug resistance has become one of the main challenges for the failure of chemotherapy, greatly limiting the selection and use of anticancer drugs and dashing the hopes of cancer patients. The emergence of supramolecular host-guest nanosystems has brought the field of supramolecular chemistry into the nanoworld, providing a potential solution to this challenge. Compared with conventional chemotherapeutic platforms, supramolecular host-guest nanosystems can reverse cancer drug resistance by increasing drug uptake, reducing drug efflux, activating drugs, and inhibiting DNA repair. Herein, we summarize the research progress of supramolecular host-guest nanosystems for overcoming cancer drug resistance and discuss the future research direction in this field. It is hoped that this review will provide more positive references for overcoming cancer drug resistance and promoting the development of supramolecular host-guest nanosystems.

A shift in focus towards precision oncology, driven by revolutionary nanodiagnostics; revealing mysterious pathways in colorectal carcinogenesis

Multiple molecular mechanisms contribute to the development of colorectal cancer (CRC), with chromosomal instability (CIN) playing a significant role. CRC is influenced by mutations in several important genes, including APC, TP53, KRAS, PIK3CA, BRAF, and SMYD4. The three molecular subtypes of this disease are CIN, MSI-H, and CIMP (CpG-island phenotype). p53 dysfunction and aberrant Wnt signalling are common characteristics of CRC carcinogenesis. Despite advances in conventional therapy, metastatic CRC remains difficult to treat due to toxicity and resistance. Theranostics for cancer could significantly benefit from nanotechnology, as it would enable more targeted, individualised care with fewer side effects. Utilising functionalized nanoparticles has enabled MRI-guided gene therapy, magnetic hyperthermia, chemotherapy, immunotherapy, and photothermal/photodynamic therapy, thereby radically modifying the way cancer is treated. Active targeting using ligands or peptides on nanoparticles improves the delivery of drugs to cancer cells. Nanostructures such as drug peptide conjugates, chitosan nanoparticles, gold nanoparticles, carbon nanotubes, mesoporous silica-based nanoparticles, silver nanoparticles, hybrid lipid-polymer nanoparticles, iron oxide nanoparticles, and quantum dots may enable targeted drug delivery and enhanced therapeutic efficacy against CRC. Nanomedicines are presently being evaluated in clinical trials for the treatment of colorectal cancer, with the promise of more effective and individualised therapies. This article examines current nanomedicine patents for CRC, including the work of Delta-Fly, Merrimack, and Pfenning, Meaning & Partner, among others. In terms of future nanomedicine research and development, ligand production, particle size, and clearance are crucial factors. Lastly, the numerous nanostructures utilized in nanomedicine for targeted drug administration and diagnostics indicate optimistic prospects for enhancing CRC treatment. The successes of nanomedicine research and development for existing colon cancer treatments are also highlighted in this review.

Advances in the structure, mechanism and targeting of chemoresistance-linked ABC transporters

Cancer cells frequently display intrinsic or acquired resistance to chemically diverse anticancer drugs, limiting therapeutic success. Among the main mechanisms of this multidrug resistance is the overexpression of ATP-binding cassette (ABC) transporters that mediate drug efflux, and, specifically, ABCB1, ABCG2 and ABCC1 are known to cause cancer chemoresistance. High-resolution structures, biophysical and in silico studies have led to tremendous progress in understanding the mechanism of drug transport by these ABC transporters, and several promising therapies, including irradiation-based immune and thermal therapies, and nanomedicine have been used to overcome ABC transporter-mediated cancer chemoresistance. In this Review, we highlight the progress achieved in the past 5 years on the three transporters, ABCB1, ABCG2 and ABCC1, that are known to be of clinical importance. We address the molecular basis of their broad substrate specificity gleaned from structural information and discuss novel approaches to block the function of ABC transporters. Furthermore, genetic modification of ABC transporters by CRISPR-Cas9 and approaches to re-engineer amino acid sequences to change the direction of transport from efflux to import are briefly discussed. We suggest that current information regarding the structure, mechanism and regulation of ABC transporters should be used in clinical trials to improve the efficiency of chemotherapeutics for patients with cancer.

Polyphenol-Based Nanosystems for Next-Generation Cancer Therapy: Multifunctionality, Design, and Challenges

With the continuous updating of cancer treatment methods and the rapid development of precision medicine in recent years, there are higher demands for advanced and versatile drug delivery systems. Scientists are committed to create greener and more effective nanomedicines where the carrier is no longer limited to a single function of drug delivery. Polyphenols, which can act as both active ingredients and fundamental building blocks, are being explored as potential multifunctional carriers that are efficient and safe for design purposes. Due to their intrinsic anticancer activity, phenolic compounds have shown surprising expressiveness in ablation of tumor cells, overcoming cancer multidrug resistance (MDR), and enhancing immunotherapeutic efficacy. This review provides an overview of recent advances in the design, synthesis, and application of versatile polyphenol-based nanosystems for cancer therapy in various modes. Moreover, the merits of polyphenols and the challenges for their clinical translation are also discussed, and it is pointed out that the novel polyphenol delivery system requires further optimization and validation.

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.

Perspectives on drug repurposing to overcome cancer multidrug resistance mediated by ABCB1 and ABCG2

The overexpression of the human ATP-binding cassette (ABC) transporters in cancer cells is a common mechanism involved in developing multidrug resistance (MDR). Unfortunately, there are currently no approved drugs specifically designed to treat multidrug-resistant cancers, making MDR a significant obstacle to successful chemotherapy. Despite over two decades of research, developing transporter-specific inhibitors for clinical use has proven to be a challenging endeavor. As an alternative approach, drug repurposing has gained traction as a more practical method to discover clinically effective modulators of drug transporters. This involves exploring new indications for already-approved drugs, bypassing the lengthy process of developing novel synthetic inhibitors. In this context, we will discuss the mechanisms of ABC drug transporters ABCB1 and ABCG2, their roles in cancer MDR, and the inhibitors that have been evaluated for their potential to reverse MDR mediated by these drug transporters. Our focus will be on providing an up-to-date report on approved drugs tested for their inhibitory activities against these drug efflux pumps. Lastly, we will explore the challenges and prospects of repurposing already approved medications for clinical use to overcome chemoresistance in patients with high tumor expression of ABCB1 and/or ABCG2.

Photo-Enhanced Synergistic Induction of Ferroptosis for Anti-Cancer Immunotherapy

Ferroptosis as programmed cell death received considerable attention in cancer research. Recently, studies have associated ferroptosis with photodynamic therapy (PDT) because PDT promotes glutathione (GSH) deletion, glutathione peroxidase 4 (GPX4) degradation, and lipid peroxide accumulation. However, PDT-induced ferroptosis may be potentially prevented by ferroptosis suppressor protein 1 (FSP1). To address this limitation, herein, a novel strategy is developed to trigger ferroptosis by PDT and FSP1 inhibition. For enhancement of this strategy, a photoresponsive nanocomplex, self-assembled by BODIPY-modified poly(amidoamine) (BMP), is utilized to stably encapsulate the inhibitor of FSP1 (iFSP1) and chlorin e6 (Ce6). The nanosystem promotes intracellular delivery, penetration, and accumulation of ferroptosis inducers in tumors with light irradiation. The nanosystem presents high-performance triggering of ferroptosis and immunogenic cell death (ICD) in vitro and in vivo. Importantly, the nanoparticles increase tumor infiltration of CD8+ T cells and further enhance the efficacy of anti-PD-L1 immunotherapy. The study suggests the potential of photo-enhanced synergistic induction of ferroptosis by the photoresponsive nanocomplexes in cancer immunotherapy.

ABC transporter-mediated MXR mechanism in fish embryos and its potential role in the efflux of nanoparticles

ATP-binding cassette (ABC) transporters are believed to protect aquatic organisms by pumping xenobiotics out, and recent investigation has suggested their involvement in the detoxification and efflux of nanoparticles (NPs), but their roles in fish embryos are poorly understood. In this regard, this paper summarizes the recent advances in research pertaining to the development of ABC transporter-mediated multi-xenobiotic resistance (MXR) mechanism in fish embryos and the potential interaction between ABC transporters and NPs. The paper focuses on: (1) Expression, function, and modulation mechanism of ABC proteins in fish embryos; (2) Potential interaction between ABC transporters and NPs in cell models and fish embryos. ABC transporters could be maternally transferred to fish embryos and thus play an important role in the detoxification of various chemical pollutants and NPs. There is a need to understand the specific mechanism to benefit the protection of aquatic resources.

Sonocatalytic Optimization of Titanium-Based Therapeutic Nanomedicine

Recent considerable technological advances in ultrasound-based treatment modality provides a magnificent prospect for scientific communities to conquer the related diseases, which is featured with remarkable tissue penetration, non-invasive and non-thermal characteristics. As one of the critical elements that influences treatment outcomes, titanium (Ti)-based sonosensitizers with distinct physicochemical properties and exceptional sonodynamic efficiency have been applied extensively in the field of nanomedical applications. To date, a myriad of methodologies has been designed to manipulate the sonodynamic performance of titanium-involved nanomedicine and further enhance the productivity of reactive oxygen species for disease treatments. In this comprehensive review, the sonocatalytic optimization of diversified Ti-based nanoplatforms, including defect engineering, plasmon resonance modulation, heterojunction, modulating tumor microenvironment, as well as the development of synergistic therapeutic modalities is mainly focused. The state-of-the-art Ti-based nanoplatforms ranging from preparation process to the extensive medical applications are summarized and highlighted, with the goal of elaborating on future research prospects and providing a perspective on the bench-to-beside translation of these sonocatalytic optimization tactics. Furthermore, to spur further technological advancements in nanomedicine, the difficulties currently faced and the direction of sonocatalytic optimization of Ti-based therapeutic nanomedicine are proposed and outlooked.

Purinergic signalling in cancer therapeutic resistance: From mechanisms to targeting strategies

Purinergic signalling, consisting of extracellular purines and purinergic receptors, modulates cell proliferation, invasion and immunological reaction during cancer progression. Here, we focus on current evidence that suggests the crucial role of purinergic signalling in mediating cancer therapeutic resistance, the major obstacle in cancer treatment. Mechanistically, purinergic signalling can modulate the tumor microenvironment (TME), epithelial-mesenchymal transition (EMT) and anti-tumor immunity, thus affecting drug sensitivity of tumor cells. Currently, some agents attempting to target purinergic signalling either in tumor cells or in tumor-associated immune cells are under preclinical or clinical investigation. Moreover, nano-based delivery technologies significantly improve the efficacy of agents targeting purinergic signalling. In this review article, we summarize the mechanisms of purinergic signalling in promoting cancer therapeutic resistance and discuss the potentials and challenges of targeting purinergic signalling in future cancer treatment.

Flavonoids as P-glycoprotein inhibitors for multidrug resistance in cancer: an in-silico approach

Cancer has become a leading cause of mortality due to non-communicable diseases after cardiovascular disease worldwide and is increasing day by day at a daunting pace. According to an estimate by 2040 there will be 28.4 million cancer cases. Occurrence of multidrug resistance has further worsened the scenario of available cancer treatment. Among different mechanisms of multidrug resistance efflux of xenobiotics by ABC transporter is of prime importance. P-glycoprotein (P-gp) is the major factor behind occurrence of multidrug resistance due to its wide distribution and invariably big binding cavity. Various generations of chemical inhibitors for P-gp have been designed and tested are not devoid of major side effects. Thus, in present study flavonoids a major class of natural compounds was virtually screened in order to find molecules which can be used as selective P-gp inhibitors to be used along with chemotherapeutics. After screening 4275 molecules from different classes of flavonoids i.e. flavan, flavanol, flavonone, flavone, anthocyanins, and isoflavone, through Glide docking top ten hit molecules were selected based on their binding affinity, binding energy calculation and pharmacokinetic properties. All the hit molecules were found to have docking score within the range of -11.202 to -9.699 kcal/mol showing very strong interaction with the amino acid residues of binding pocket. Whereas, dock score of standard P-gp inhibitor verapamil was -4.984 kcal/mol. The ligand and protein complex were found to be quite stable while run through molecular dynamics simulations.Communicated by Ramaswamy H. Sarma.

Current advances in nanoformulations of therapeutic agents targeting tumor microenvironment to overcome drug resistance

The tumor microenvironment (TME) plays a pivotal role in cancer development and progression. In this line, revealing the precise mechanisms of the TME and associated signaling pathways of tumor resistance could pave the road for cancer prevention and efficient treatment. The use of nanomedicine could be a step forward in overcoming the barriers in tumor-targeted therapy. Novel delivery systems benefit from enhanced permeability and retention effect, decreasing tumor resistance, reducing tumor hypoxia, and targeting tumor-associated factors, including immune cells, endothelial cells, and fibroblasts. Emerging evidence also indicates the engagement of multiple dysregulated mediators in the TME, such as matrix metalloproteinase, vascular endothelial growth factor, cytokines/chemokines, Wnt/β-catenin, Notch, Hedgehog, and related inflammatory and apoptotic pathways. Hence, investigating novel multitargeted agents using a novel delivery system could be a promising strategy for regulating TME and drug resistance. In recent years, small molecules from natural sources have shown favorable anticancer responses by targeting TME components. Nanoformulations of natural compounds are promising therapeutic agents in simultaneously targeting multiple dysregulated factors and mediators of TME, reducing tumor resistance mechanisms, overcoming interstitial fluid pressure and pericyte coverage, and involvement of basement membrane. The novel nanoformulations employ a vascular normalization strategy, stromal/matrix normalization, and stress alleviation mechanisms to exert higher efficacy and lower side effects. Accordingly, the nanoformulations of anticancer monoclonal antibodies and conventional chemotherapeutic agents also improved their efficacy and lessened the pharmacokinetic limitations. Additionally, the coadministration of nanoformulations of natural compounds along with conventional chemotherapeutic agents, monoclonal antibodies, and nanomedicine-based radiotherapy exhibits encouraging results. This critical review evaluates the current body of knowledge in targeting TME components by nanoformulation-based delivery systems of natural small molecules, monoclonal antibodies, conventional chemotherapeutic agents, and combination therapies in both preclinical and clinical settings. Current challenges, pitfalls, limitations, and future perspectives are also discussed.

Metal-organic-framework-based pyroptosis nanotuner with long blood circulation for augmented chemotherapy

Pyroptosis is a proinflammatory form of cell death mediated by members of the gasdermin family, and is a powerful tool against cancer. Herein, a pH-responsive doxorubicin (DOX)-encapsulating zeolitic imidazolate framework-8 (ZIF-8) nanoparticle coated with a carboxybetaine-based zwitterionic polymer (DOX@ZIF-8@PCBMA) was prepared. Furthermore, decitabine (DAC) was loaded to obtain a pyroptosis nanotuner (DOX@ZIF-8@PCBMA-DAC). This nanotuner displayed extended blood circulation and enhanced tumor accumulation. In addition, the ZIF-8 structure and disulfide-crosslinked PCBMA coating endowed DOX@ZIF-8@PCBMA-DAC with acidic-pH- and glutathione-responsive degradation. The nanotuner could robustly activate caspase-3 to induce gasdermin E (GSDME)-dependent pyroptosis via the sustained release of DAC and DOX, contributing to excellent tumor suppression with negligible side effects, which may provide novel insights into traditional chemotherapy.

CINOVA: a phase II study of CPC634 (nanoparticulate docetaxel) in patients with platinum resistant recurrent ovarian cancer

OBJECTIVE

Recurrent platinum-resistant ovarian cancer has a poor prognosis with limited therapeutic options. Sub-therapeutic intra-tumoral drug concentrations may add to therapy resistance. CPC634 (docetaxel entrapped in CriPec nanoparticles) was designed to enhance tumor accumulation of drug with localized drug release at the target site to increase therapeutic efficacy. This study investigated the therapeutic effect of CPC634 in patients with platinum-resistant ovarian cancer.

METHODS

According to a Simon 2-stage design trial, the first stage included 13 patients, and 12 patients were enrolled in the second stage. Eligible patients had measurable disease and had progressed ≤6 months after the last platinum-based therapy. Platinum-refractory disease was excluded. In stage 1, the number of previous treatment lines was unlimited; in the second stage, a maximum of two prior lines altogether were allowed. The primary endpoint was the objective response rate by Response Evaluation Criteria in Solid Tumor (RECIST) V1.1. Secondary endpoints included safety, progression-free survival at 6 months, cancer antigen 125 (CA125) response, and disease control rate.

RESULTS

The patients' median age was 66 years (range 22-77) and most were International Federation of Gynecology and Obstetrics (FIGO) stage III (56%). The median number of previous treatment lines was 3 (range 3-5) in stage I and 2 (range 1-4) in stage II of the study. None of the patients had an objective response, one patient had a CA125 response (5%), and seven patients had stable disease at first evaluation (35%). Median progression-free survival was 1.4 months in stage 1 and 3.0 months in stage 2. Adverse events (all grades) were mainly gastrointestinal in 24 patients (96%), fatigue in 11 (44%), dyspnea in 10 (40%), and infections in 10 (40%) of patients. Grade 3 or higher adverse events occurred in 14 patients (36%), including gastrointestinal in 4 (16%), anemia in 3 (12%), and febrile neutropenia, fatigue, chronic kidney disease, dehydration, and hypertension each in 1 (4%) patient. The trial was stopped prematurely due to futility.

CONCLUSIONS

Treatment with CPC634 was feasible, but without apparent clinical activity in patients with recurrent platinum-resistant ovarian cancer. Side effects were mainly gastrointestinal in 24 (96%) patients, including nausea, vomiting, and decreased appetite, fatigue, anemia, and dyspnea.

Nano-engineering nanomedicines with customized functions for tumor treatment applications

Nano-engineering with unique "custom function" capability has shown great potential in solving technical difficulties of nanomaterials in tumor treatment. Through tuning the size and surface properties controllablly, nanoparticles can be endoewd with tailored structure, and then the characteristic functions to improve the therapeutic effect of nanomedicines. Based on nano-engineering, many have been carried out to advance nano-engineering nanomedicine. In this review, the main research related to cancer therapy attached to the development of nanoengineering nanomedicines has been presented as follows. Firstly, therapeutic agents that target to tumor area can exert the therapeutic effect effectively. Secondly, drug resistance of tumor cells can be overcome to enhance the efficacy. Thirdly, remodeling the immunosuppressive microenvironment makes the therapeutic agents work with the autoimmune system to eliminate the primary tumor and then prevent tumor recurrence and metastasis. Finally, the development prospects of nano-engineering nanomedicine are also outlined.

Advances of medical nanorobots for future cancer treatments

Early detection and diagnosis of many cancers is very challenging. Late stage detection of a cancer always leads to high mortality rates. It is imperative to develop novel and more sensitive and effective diagnosis and therapeutic methods for cancer treatments. The development of new cancer treatments has become a crucial aspect of medical advancements. Nanobots, as one of the most promising applications of nanomedicines, are at the forefront of multidisciplinary research. With the progress of nanotechnology, nanobots enable the assembly and deployment of functional molecular/nanosized machines and are increasingly being utilized in cancer diagnosis and therapeutic treatment. In recent years, various practical applications of nanobots for cancer treatments have transitioned from theory to practice, from in vitro experiments to in vivo applications. In this paper, we review and analyze the recent advancements of nanobots in cancer treatments, with a particular emphasis on their key fundamental features and their applications in drug delivery, tumor sensing and diagnosis, targeted therapy, minimally invasive surgery, and other comprehensive treatments. At the same time, we discuss the challenges and the potential research opportunities for nanobots in revolutionizing cancer treatments. In the future, medical nanobots are expected to become more sophisticated and capable of performing multiple medical functions and tasks, ultimately becoming true nanosubmarines in the bloodstream.

Advances of nanotechnology applied to cancer stem cells

Cancer stem cells (CSCs) are a small proportion of the cells that exist in cancer tissues. They are considered to be the culprit of tumor genesis, development, drug resistance, metastasis and recurrence because of their self-renewal, proliferation, and differentiation potential. The elimination of CSCs is thus the key to cure cancer, and targeting CSCs provides a new method for tumor treatment. Due to the advantages of controlled sustained release, targeting and high biocompatibility, a variety of nanomaterials are used in the diagnosis and treatments targeting CSCs and promote the recognition and removal of tumor cells and CSCs. This article mainly reviews the research progress of nanotechnology in sorting CSCs and nanodrug delivery systems targeting CSCs. Furthermore, we identify the problems and future research directions of nanotechnology in CSC therapy. We hope that this review will provide guidance for the design of nanotechnology as a drug carrier so that it can be used in clinic for cancer therapy as soon as possible.

Recent advances in access to overcome cancer drug resistance by nanocarrier drug delivery system

Cancer is currently one of the most intractable diseases causing human death. Although the prognosis of tumor patients has been improved to a certain extent through various modern treatment methods, multidrug resistance (MDR) of tumor cells is still a major problem leading to clinical treatment failure. Chemotherapy resistance refers to the resistance of tumor cells and/or tissues to a drug, usually inherent or developed during treatment. Therefore, an urgent need to research the ideal drug delivery system to overcome the shortcoming of traditional chemotherapy. The rapid development of nanotechnology has brought us new enlightenments to solve this problem. The novel nanocarrier provides a considerably effective treatment to overcome the limitations of chemotherapy or other drugs resulting from systemic side effects such as resistance, high toxicity, lack of targeting, and off-target. Herein, we introduce several tumor MDR mechanisms and discuss novel nanoparticle technology applied to surmount cancer drug resistance. Nanomaterials contain liposomes, polymer conjugates, micelles, dendrimers, carbon-based, metal nanoparticles, and nucleotides which can be used to deliver chemotherapeutic drugs, photosensitizers, and small interfering RNA (siRNA). This review aims to elucidate the advantages of nanomedicine in overcoming cancer drug resistance and discuss the latest developments.

Heterocyclic Molecular Targeted Drugs and Nanomedicines for Cancer: Recent Advances and Challenges

Cancer is a top global public health concern. At present, molecular targeted therapy has emerged as one of the main therapies for cancer, with high efficacy and safety. The medical world continues to struggle with the development of efficient, extremely selective, and low-toxicity anticancer medications. Heterocyclic scaffolds based on the molecular structure of tumor therapeutic targets are widely used in anticancer drug design. In addition, a revolution in medicine has been brought on by the quick advancement of nanotechnology. Many nanomedicines have taken targeted cancer therapy to a new level. In this review, we highlight heterocyclic molecular-targeted drugs as well as heterocyclic-associated nanomedicines in cancer.

Glutathione-Responsive Tannic Acid-Assisted FRET Nanomedicine for Cancer Therapy

In cancer combination therapy, a multimodal delivery vector is used to improve the bioavailability of multiple anti-cancer hydrophobic drugs. Further, targeted delivery of therapeutics along with simultaneous monitoring of the drug release at the tumor site without normal organ toxicity is an emerging and effective strategy for cancer treatment. However, the lack of a smart nano-delivery system limits the application of this therapeutic strategy. To overcome this issue, a PEGylated dual drug, conjugated amphiphilic polymer (CPT-S-S-PEG-CUR), has been successfully synthesized by conjugating two hydrophobic fluorescent anti-cancer drugs, curcumin (CUR) and camptothecin (CPT), through an ester and a redox-sensitive disulfide (-S-S-) linkage, respectively, with a PEG chain via in situ two-step reactions. CPT-S-S-PEG-CUR is spontaneously self-assembled in the presence of tannic acid (TA, a physical crosslinker) into anionic, comparatively smaller-sized (~100 nm), stable nano-assemblies in water in comparison to only polymer due to stronger H-bond formation between polymer and TA. Further, due to the spectral overlap between CPT and CUR and a stable, smaller nano-assembly formation by the pro-drug polymer in water in presence of TA, a successful Fluorescence Resonance Energy Transfer (FRET) signal was generated between the conjugated CPT (FRET donor) and conjugated CUR (FRET acceptor). Interestingly, these stable nano-assemblies showed a preferential breakdown and release of CPT in a tumor-relevant redox environment (in the presence of 50 mM glutathione), leading to the disappearance of the FRET signal. These nano-assemblies exhibited a successful cellular uptake by the cancer cells and an enhanced antiproliferative effect in comparison to the individual drugs in cancer cells (AsPC1 and SW480). Such promising in vitro results with a novel redox-responsive, dual-drug conjugated, FRET pair-based nanosized multimodal delivery vector can be highly useful as an advanced theranostic system towards effective cancer treatment.

A multi-functional nano-system combining PI3K-110α/β inhibitor overcomes P-glycoprotein mediated MDR and improves anti-cancer efficiency

P-glycoprotein (P-gp/ABCB1)-mediated multidrug resistance (MDR) in cancers severely limit chemotherapeutic efficacy. We recently reported that phosphatidylinositol-3-kinase (PI3K) 110α and 110β subunits can be novel targets for reversal of P-gp mediated MDR in cancers, and BAY-1082439 as an inhibitor specific for PI3K 110α and 110β subunits could reverse P-gp-mediated MDR by downregulating P-gp expression in cancer cells. However, BAY-1082439 has very low solubility, short half-life and high in-vivo clearance rate. Till now, nano-system with the functions to target PI3K P110α and P110β and reverse P-gp mediated MDR in cancers has not been reported. In our study, a tumor targeting drug delivery nano-system PBDF was established, which comprised doxorubicin (DOX) and BAY-1082439 respectively encapsulated by biodegradable PLGA-SH nanoparticles (NPs) that were grafted to gold nanorods (Au NRs) modified with FA-PEG-SH, to enhance the efficacy to reverse P-gp mediated MDR and to target tumor cells, further, to enhance the efficiency to inhibit MDR tumors overexpressing P-gp. In-vitro experiments indicated that PBDF NPs greatly enhanced uptake of DOX, improved the activity to reverse MDR, inhibited the cell proliferation, and induced S-phase arrest and apoptosis in KB-C2 cells, as compared with free DOX combining free BAY-1082439. In-vivo experiments further demonstrated that PBDF NPs improved the anti-tumor ability of DOX and inhibited development of KB-C2 tumors. Notably, the metastasis of KB-C2 cells in livers and lungs of nude mice were inhibited by treatment with PBDF NPs, which showed no obvious in-vitro or in-vivo toxicity.

Flower-like Nanozyme with Highly Porous Carbon Matrix Induces Robust Oxidative Storm against Drug-Resistant Cancer

Reactive oxygen species (ROS) generators are sparking breakthroughs in sensitization and treatment of therapy-resistant tumors, yet the efficacy is drastically compromised by limited substrate concentrations, short lifetimes of free radicals, and restricted oxidative damage. Herein, a flower-like nanozyme with highly permeable leaflets accommodating catalytic metal sites was developed to address the challenges by boosting substrate and product accessibility. In the formation of a zeolite imidazole framework, cobalt ions promoted catalytic polymerization and deposition of polydopamine. The polymers acted as a stiffener for preventing framework collapse and maneuvering pore reopening during carbonization. The cobalt single-atom/cluster sites in the highly porous matrix generated peroxidase/oxidase-like activities with high catalytic efficiency (K_cat/K_m) up to 6 orders of magnitude greater than that of conventional nano-/biozymes. Thereby, a robust ROS storm induced by selective catalysis led to rapid accumulation of oxidative damage and failure of antioxidant and antiapoptotic defense synchronization in drug-resistant cancer cells. By synergy of a redox homeostasis disrupter co-delivered, a significantly high antitumor efficiency was realized in vivo. This work offers a route to kinetically favorable ROS generators for advancing the treatment of therapy-resistant tumors.

NIR Activated Multimodal Therapeutics Based on Metal-Phenolic Networks-Functionalized Nanoplatform for Combating against Multidrug Resistance and Metastasis

Multidrug resistance (MDR) and metastasis in cancer have become increasingly serious problems since antitumor efficiency is greatly restricted by a single therapeutic modality and the insensitive tumor microenvironment (TME). Herein, metal-phenolic network-functionalized nanoparticles (t-P@TFP NPs) are designed to realize multiple therapeutic modalities and reshape the TME from insensitive to sensitive under multimodal imaging monitoring. After a single irradiation, a near-infrared laser-activated multistage reaction occurs. t-P@TFP NPs trigger the phase transition of perfluoropentane (PFP) to release tannic acid (TA)/ferric ion (Fe³⁺ )-coated paclitaxel (PTX) and cause hyperthermia in the tumor region to efficiently kill cancer cells. Additionally, PTX is released after the disassembly of the TA-Fe³⁺ film by the abundant adenosine triphosphate (ATP) in the malignant tumor, which concurrently inhibits ATP-dependent drug efflux to improve sensitivity to chemotherapeutic agents. Furthermore, hyperthermia-induced immunogenic cell death (ICD) transforms "cold" tumors into "hot" tumors with the assistance of PD-1/PD-L1 blockade to evoke antitumor immunogenicity. This work carefully reveals the mechanisms underlying the abilities of these multifunctional NPs, providing new insights into combating the proliferation and metastasis of multidrug-resistant tumors.

Dual-drug codelivery nanosystems: An emerging approach for overcoming cancer multidrug resistance

Multidrug resistance (MDR) promotes tumor recurrence and metastasis and heavily reduces anticancer efficiency, which has become a primary reason for the failure of clinical chemotherapy. The mechanisms of MDR are so complex that conventional chemotherapy usually fails to achieve an ideal therapeutic effect and even accelerates the occurrence of MDR. In contrast, the combination of chemotherapy with dual-drug has significant advantages in tumor therapy. A novel dual-drug codelivery nanosystem, which combines dual-drug administration with nanotechnology, can overcome the application limitation of free drugs. Both the characteristics of nanoparticles and the synergistic effect of dual drugs contribute to circumventing various drug-resistant mechanisms in tumor cells. Therefore, developing dual-drug codelivery nanosystems with different multidrug-resistant mechanisms has an important reference value for reversing MDR and enhancing the clinical antitumor effect. In this review, the advantages, principles, and common codelivery nanocarriers in the application of dual-drug codelivery systems are summarized. The molecular mechanisms of MDR and the dual-drug codelivery nanosystems designed based on different mechanisms are mainly introduced. Meanwhile, the development prospects and challenges of codelivery nanosystems are also discussed, which provide guidelines to exploit optimized combined chemotherapy strategies in the future.

Nanocarriers overcoming biological barriers induced by multidrug resistance of chemotherapeutics in 2D and 3D cancer models

Multidrug resistance (MDR) is currently a big challenge in cancer therapy and limits its success in several patients. Tumors use the MDR mechanisms to colonize the host and reduce the efficacy of chemotherapeutics that are injected as single agents or combinations. MDR mechanisms are responsible for inactivation of drugs and formbiological barriers in cancer like the drug efflux pumps, aberrant extracellular matrix, hypoxic areas, altered cell death mechanisms, etc. Nanocarriers have some potential to overcome these barriers and improve the efficacy of chemotherapeutics. In fact, they are versatile and can deliver natural and synthetic biomolecules, as well as RNAi/DNAi, thus providing a controlled release of drugs and a synergistic effect in tumor tissues. Biocompatible and safe multifunctional biopolymers, with or without specific targeting molecules, modify the surface and interface properties of nanocarriers. These modifications affect the interaction of nanocarriers with cellular models as well as the selection of suitable models for in vitro experiments. MDR cancer cells, and particularly their 2D and 3D models, in combination with anatomical and physiological structures of tumor tissues, can boost the design and preparation of nanomedicines for anticancer therapy. 2D and 3D cancer cell cultures are suitable models to study the interaction, internalization, and efficacy of nanocarriers, the mechanisms of MDR in cancer cells and tissues, and they are used to tailor a personalized medicine and improve the efficacy of anticancer treatment in patients. The description of molecular mechanisms and physio-pathological pathways of these models further allow the design of nanomedicine that can efficiently overcome biological barriers involved in MDR and test the activity of nanocarriers in 2D and 3D models of MDR cancer cells.

Polymer- and lipid-based nanocarriers for ocular drug delivery: Current status and future perspectives

Ocular diseases seriously affect patients' vision and life quality, with a global morbidity of over 43 million blindness. However, efficient drug delivery to treat ocular diseases, particularly intraocular disorders, remains a huge challenge due to multiple ocular barriers that significantly affect the ultimate therapeutic efficacy of drugs. Recent advances in nanocarrier technology offer a promising opportunity to overcome these barriers by providing enhanced penetration, increased retention, improved solubility, reduced toxicity, prolonged release, and targeted delivery of the loaded drug to the eyes. This review primarily provides an overview of the progress and contemporary applications of nanocarriers, mainly polymer- and lipid-based nanocarriers, in treating various eye diseases, highlighting their value in achieving efficient ocular drug delivery. Additionally, the review covers the ocular barriers and administration routes, as well as the prospective future developments and challenges in the field of nanocarriers for treating ocular diseases.

Recent Progress in Carrier-Free Nanomedicine for Tumor Phototherapy

Safe and effective strategies are urgently needed to fight against the life-threatening diseases of various cancers. However, traditional therapeutic modalities, such as radiotherapy, chemotherapy and surgery, exhibit suboptimal efficacy for malignant tumors owing to the serious side effects, drug resistance and even relapse. Phototherapies, including photodynamic therapy (PDT) and photothermal therapy (PTT), are emerging therapeutic strategies for localized tumor inhibition, which can produce a large amount of reactive oxygen species (ROS) or elevate the temperature to initiate cell death by non-invasive irradiation. In consideration of the poor bioavailability of phototherapy agents (PTAs), lots of drug delivery systems have been developed to enhance the tumor targeted delivery. Nevertheless, the carriers of drug delivery systems inevitably bring biosafety concerns on account of their metabolism, degradation, and accumulation. Of note, carrier-free nanomedicine attracts great attention for clinical translation with synergistic antitumor effect, which is characterized by high drug loading, simplified synthetic method and good biocompatibility. In this review, the latest advances of phototherapy with various carrier-free nanomedicines are summarized, which may provide a new paradigm for the future development of nanomedicine and tumor precision therapy.

Acoustically-Activated Liposomal Nanocarriers to Mitigate the Side Effects of Conventional Chemotherapy with a Focus on Emulsion-Liposomes

To improve currently available cancer treatments, nanomaterials are employed as smart drug delivery vehicles that can be engineered to locally target cancer cells and respond to stimuli. Nanocarriers can entrap chemotherapeutic drugs and deliver them to the diseased site, reducing the side effects associated with the systemic administration of conventional anticancer drugs. Upon accumulation in the tumor cells, the nanocarriers need to be potentiated to release their therapeutic cargo. Stimulation can be through endogenous or exogenous modalities, such as temperature, electromagnetic irradiation, ultrasound (US), pH, or enzymes. This review discusses the acoustic stimulation of different sonosensitive liposomal formulations. Emulsion liposomes, or eLiposomes, are liposomes encapsulating phase-changing nanoemulsion droplets, which promote acoustic droplet vaporization (ADV) upon sonication. This gives eLiposomes the advantage of delivering the encapsulated drug at low intensities and short exposure times relative to liposomes. Other formulations integrating microbubbles and nanobubbles are also discussed.

Cyperotundone combined with adriamycin induces apoptosis in MCF-7 and MCF-7/ADR cancer cells by ROS generation and NRF2/ARE signaling pathway

Breast cancer has become the most prevalent cancer, globally. Adriamycin is a first-line chemotherapeutic agent, however, cancer cells acquire resistance to it, which is one of the most common causes of treatment failure. ROS and NRF2 are essential oxidative stress factors that play a key role in the oxidative stress process and are associated with cancer. Our goal is to create novel therapeutic drugs or chemical sensitizers that will improve chemotherapy sensitivity. The optimal concentration and duration for MCF-7 and MCF-7/ADR cells in ADR and CYT were determined using the CCK-8 assay. We found that ADR + CYT inhibited the activity of MCF-7 and MCF-7/ADR cells in breast cancer, as well as causing apoptosis in MCF-7 and MCF-7/ADR cells and blocking the cell cycle in the G0/G1 phase. ADR + CYT induces apoptosis in MCF-7 and MCF-7/ADR cells through ROS generation and the P62/NRF2/HO-1 signaling pathway. In breast cancer-bearing nude mice, ADR + CYT effectively suppressed tumor development in vivo. Overall, our findings showed that CYT in combination with ADR has potent anti-breast cancer cell activity both in vivo and in vitro, suggesting CYT as the main drug used to improve chemosensitivity.

Nanotechnology-based approaches overcome lung cancer drug resistance through diagnosis and treatment

Lung cancer continues to be a malignant tumor with high mortality. Two obstacles interfere with curative therapy of lung cancer: (i) poor diagnosis at the early stages, as symptoms are not specific or asymptomatic; and (ii) invariably emerging drug resistance after treatment. Some factors contributing to drug resistance include preexisting genetic/genomic drug-resistant alteration(s); activation of adaptive drug resistance pathways; remodeling of the tumor microenvironment; and pharmacological mechanisms or activation of drug efflux pumps. Despite the mechanisms explored to better understand drug resistance, a gap remains between molecular understanding and clinical application. Therefore, facilitating the translation of basic science into the clinical setting is a great challenge. Nanomedicine has emerged as a promising tool for cancer treatment. Because of their excellent physicochemical properties and enhanced permeability and retention effects, nanoparticles have great potential to revolutionize conventional lung cancer diagnosis and combat drug resistance. Nanoplatforms can be designed as carriers to improve treatment efficacy and deliver multiple drugs in one system, facilitating combination treatment to overcome drug resistance. In this review, we describe the difficulties in lung cancer treatment and review recent research progress on nanoplatforms aimed at early diagnosis and lung cancer treatment. Finally, future perspectives and challenges of nanomedicine are also discussed.

CHD4 promotes acquired chemoresistance and tumor progression by activating the MEK/ERK axis

AIMS

Chemoresistance remains a major challenge in gastric cancer (GC). Chromodomain helicase DNA-binding protein 4 (CHD4) mediated chromatin remodeling plays critical roles in various tumor types, but its role in chemoresistance in GC remains uncharacterized.

METHODS

CHD4 expression was examined by immunohistochemistry and Western blotting. The role of CHD4 on cell proliferation and chemoresistance of GC was examined in vitro and in vivo. Immunoprecipitation and liquid chromatography-mass spectrometry were used to identify CHD4-binding proteins and a proximity ligation assay was used to explore protein-protein interaction.

RESULTS

Chemoresistance is associated with upregulation of CHD4 in the tumor tissues of GC patients. Overexpression of CHD4 increased chemoresistance and cell proliferation. Knockdown of CHD4 induced cell apoptosis and cell cycle arrest. CHD4 mediates the decrease of the intracellular concentration of cisplatin by inducing drug efflux. Additionally, CHD4 promotes the interaction between ERK1/2 and MEK1/2, resulting in continuous activation of MEK/ERK pathway. Knockdown of CHD4 in GC increased sensitivity to chemotherapy and suppressed tumor growth in a mouse xenograft model.

CONCLUSIONS

This study identifies CHD4 dominated multi-drug efflux as a promising therapeutic target for overcoming acquired chemoresistance in GC.

Dual-Activated Nano-Prodrug for Chemo-Photodynamic Combination Therapy of Breast Cancer

Herein, we developed a dual-activated prodrug, BTC, that contains three functional components: a glutathione (GSH)-responsive BODIPY-based photosensitizer with a photoinduced electron transfer (PET) effect between BODIPY and the 2,4-dinitrobenzenesulfonate (DNBS) group, and an ROS-responsive thioketal linker connecting BODIPY and the chemotherapeutic agent camptothecin (CPT). Interestingly, CPT displayed low toxicity because the active site of CPT was modified by the BODIPY-based macrocycle. Additionally, BTC was encapsulated with the amphiphilic polymer DSPE-mPEG₂₀₀₀ to improve drug solubility and tumor selectivity. The resulting nano-prodrug passively targeted tumor cells through enhanced permeability and retention (EPR) effects, and then the photosensitizing ability of the BODIPY dye was restored by removing the DNBS group with the high concentration of GSH in tumor cells. Light-triggered ROS from activated BODIPY can not only induce apoptosis or necrosis of tumor cells but also sever the thioketal linker to release CPT, achieving the combination treatment of selective photodynamic therapy and chemotherapy. The antitumor activity of the prodrug has been demonstrated in mouse mammary carcinoma 4T1 and human breast cancer MCF-7 cell lines and 4T1 tumor-bearing mice.