Recent updates on innovative approaches to overcome drug resistance for better outcomes in cancer

Alendronate-functionalized porous nano-crystalsomes mitigate osteolysis and consequent inhibition of tumor growth in a tibia-induced metastasis model

Bone is one of the most prevalent sites of metastases in various epithelial malignancies, including breast cancer and this metastasis to bone often leads to severe skeletal complications in women due to its osteolytic nature. To address this, we devised a novel drug delivery approach using an Alendronate (ALN) functionalized self-assembled porous crystalsomes for concurrent targeting of Oleanolic acid (OA) and ALN (ALN + OA@NCs) to bone metastasis. Initially, the conjugation of both PEG-OA and OA-PEG-ALN with ALN and OA was achieved, and this conjugation was then self-assembled into porous crystalsomes (ALN + OA@NCs) by nanoemulsion crystallization. The reconstruction of a 3D single particle using transmission electron microscopy ensured the crystalline porous structure of ALN + OA@NCs, was well aligned with characteristic nanoparticle attributes including size distribution, polydispersity, and zeta potential. Further, ALN + OA@NCs showed enhanced efficacy in comparison to OA@NCs suggesting the cytotoxic roles of ALN towards cancer cells, followed by augmentation ROS generation (40.81%), mitochondrial membrane depolarization (57.20%), and induction of apoptosis (40.43%). We found that ALN + OA@NCs facilitated inhibiting osteoclastogenesis and bone resorption followed by inhibited osteolysis. In vivo activity of ALN + OA@NCs in the 4 T1 cell-induced tibia model rendered a reduced bone loss in the treated mice followed by restoring bone morphometric markers which were further corroborated bone-targeting effects of ALN + OA@NCs to reduce RANKL-stimulated osteoclastogenesis. Further, In vivo intravenous pharmacokinetics showed the improved therapeutic profile of the ALN + OA@NCs in comparison to the free drug, prolonging the levels of the drug in the systemic compartment by reducing the clearance culminating the higher accumulation at the tumor site. Our finding proposed that ALN + OA@NCs can effectively target and treat breast cancer metastasis to bone and its associated complications.

Ultrasound-assisted encapsulating folic acid-based carbon quantum dots within breast cancer cell-derived exosomes as a co-receptors-mediated anticancer nanocarrier for enhanced breast cancer therapy

The nonspecific nature of cancer drug delivery often results in substantial toxic side effects during treatments for breast cancer. To mitigate these negative outcomes, our approach involves loading methotrexate (MTX) within carbon quantum dots (CQDs) synthesized from folic acid, which are then enveloped in exosomal membranes obtained from breast cancer cells (Ex@MTX-CQDs). Analysis utilizing nanoparticle tracking techniques has demonstrated that these Ex@MTX-CQDs maintain the physical and biochemical properties of their exosomal precursors. The release profile of MTX indicated a restricted release percentage (less than 10%) under normal physiological conditions, which is contrasted by a more consistent release rate (approximately 65%) when emulating the conditions found within tumor tissues. The toxicological assessments have confirmed that the presence of exosomes combined with leftover folic acid significantly improves the delivery efficacy of MTX directly to the cancerous cells through the binding to folate and heparan sulfate proteoglycan receptors. This process results in increased disruption of the mitochondrial membrane potential and subsequently triggers apoptosis, ultimately leading to the destruction of cancerous cells. Our research could potentially contribute to the further innovation and application of nanocarriers derived from biological sources for the targeted treatment of breast cancer.

Synthesis of a new series of 4-pyrazolylquinolinones with apoptotic antiproliferative effects as dual EGFR/BRAFV600E inhibitors

The current study focuses on developing a single molecule that acts as an antiproliferative agent with dual or multi-targeted action, reducing drug resistance and adverse effects. A new series of 4-pyrazolylquinolin-2-ones (5a-j) with apoptotic antiproliferative effects as dual EGFR/BRAFV600E inhibitors were designed and synthesized. Compounds 5a-j were investigated for their cell viability effect against a normal cell line (MCF-10A). Results showed that none of the compounds were cytotoxic, and all 5a-j demonstrated more than 90% cell viability at 50 μM concentration. Using erlotinib as a reference, the MTT assay investigated the antiproliferative impact of targets 5a-j against four human cancer cell lines. Compounds 5e, 5f, 5h, 5i, and 5j were the most potent antiproliferative agents with GI50 values of 42, 26, 29, 34, and 37 nM, making compounds 5f and 5h more potent than erlotinib (GI50 = 33 nM). Moreover, compounds 5e, 5f, 5h, 5i, and 5j were further investigated as dual EGFR/BRAFV600E inhibitors, and results revealed that compounds 5f, 5h, and 5i are potent antiproliferative agents that act as dual EGFR/BRAFV600E inhibitors. Cell cycle analysis and apoptosis detection revealed that compound 5h displaying cell cycle arrest at the G1 transition could induce apoptosis with a high necrosis percentage. Docking studies revealed that compound 5f exhibited a strong affinity for EGFR and BRAFV600E, with high docking scores of -8.55 kcal mol-1 and -8.22 kcal mol-1, respectively. Furthermore, the ADME analysis of compounds 5a-j highlighted the diversity in their pharmacokinetic properties, emphasizing the importance of experimental validation.

Regulation of ferroptosis by nanotechnology for enhanced cancer immunotherapy

INTRODUCTION

This review explores the innovative intersection of ferroptosis, a form of iron-dependent cell death, with cancer immunotherapy. Traditional cancer treatments face limitations in efficacy and specificity. Ferroptosis as a new paradigm in cancer biology, targets metabolic peculiarities of cancer cells and may potentially overcome such limitations, enhancing immunotherapy.

AREA COVERED

This review centers on the regulation of ferroptosis by nanotechnology to augment immunotherapy. It explores how nanoparticle-modulated ferroptotic cancer cells impact the TME and immune responses. The dual role of nanoparticles in modulating immune response through ferroptosis are also discussed. Additionally, it investigates how nanoparticles can be integrated with various immunotherapeutic strategies, to optimize ferroptosis induction and cancer treatment efficacy. The literature search was conducted using PubMed and Google Scholar, covering articles published up to March 2024.

EXPERT OPINION

The manuscript underscores the promising yet intricate landscape of ferroptosis in immunotherapy. It emphasizes the need for a nuanced understanding of ferroptosis' impact on immune cells and the TME to develop more effective cancer treatments, highlighting the potential of nanoparticles in enhancing the efficacy of ferroptosis and immunotherapy. It calls for deeper exploration into the molecular mechanisms and clinical potential of ferroptosis to fully harness its therapeutic benefits in immunotherapy.

Extracellular vesicles-powered immunotherapy: Unleashing the potential for safer and more effective cancer treatment

Cancer treatment has seen significant advancements with the introduction of Onco-immunotherapies (OIMTs). Although some of these therapies have received approval for use, others are either undergoing testing or are still in the early stages of development. Challenges persist in making immunotherapy widely applicable to cancer treatment. To maximize the benefits of immunotherapy and minimize potential side effects, it's essential to improve response rates across different immunotherapy methods. A promising development in this area is the use of extracellular vesicles (EVs) as novel delivery systems. These small vesicles can effectively deliver immunotherapies, enhancing their effectiveness and reducing harmful side effects. This article discusses the importance of integrating nanomedicines into OIMTs, highlighting the challenges with current anti-OIMT methods. It also explores key considerations for designing nanomedicines tailored for OIMTs, aiming to improve upon existing immunotherapy techniques. Additionally, the article looks into innovative approaches like biomimicry and the use of natural biomaterial-based nanocarriers (NCs). These advancements have the potential to transform the delivery of immunotherapy. Lastly, the article addresses the challenges of moving OIMTs from theory to clinical practice, providing insights into the future of using advanced nanotechnology in cancer treatment.

Exploring nanocarriers as innovative materials for advanced drug delivery strategies in onco-immunotherapies

In recent years, Onco-immunotherapies (OIMTs) have been shown to be a potential therapy option for cancer. Several immunotherapies have received regulatory approval, while many others are now undergoing clinical testing or are in the early stages of development. Despite this progress, a large number of challenges to the broad use of immunotherapies to treat cancer persists. To make immunotherapy more useful as a treatment while reducing its potentially harmful side effects, we need to know more about how to improve response rates to different types of immunotherapies. Nanocarriers (NCs) have the potential to harness immunotherapies efficiently, enhance the efficiency of these treatments, and reduce the severe adverse reactions that are associated with them. This article discusses the necessity to incorporate nanomedicines in OIMTs and the challenges we confront with current anti-OIMT approaches. In addition, it examines the most important considerations for building nanomedicines for OIMT, which may improve upon current immunotherapy methods. Finally, it highlights the applications and future scenarios of using nanotechnology.

Nanomedicine/materdicine-enabled sonocatalytic therapy

The advent of numerous treatment modalities with desirable therapeutic efficacy has been made possible by the fast development of nanomedicine and materdicine, among which the ultrasound (US)-triggered sonocatalytic process as minimal or non-invasive method has been frequently employed for diagnostic and therapeutic purposes. In comparison to phototherapeutic approaches with inherent penetration depth limitations, sonocatalytic therapy shatters the depth limit of photoactivation and offers numerous remarkable prospects and advantages, including mitigated side effects and appropriate tissue-penetration depth. Nevertheless, the optimization of sonosensitizers and therapies remains a significant issue in terms of precision, intelligence and efficiency. In light of the fact that nanomedicine and materdicine can effectively enhance the theranostic efficiency, we herein aim to furnish a cutting-edge review on the latest progress and development of nanomedicine/materdicine-enabled sonocatalytic therapy. The design methodologies and biological features of nanomedicine/materdicine-based sonosensitizers are initially introduced to reveal the underlying relationship between composition/structure, sonocatalytic function and biological effect, in accompany with a thorough discussion of nanomedicine/materdicine-enabled synergistic therapy. Ultimately, the facing challenges and future perspectives of this intriguing sonocatalytic therapy are highlighted and outlined to promote technological advancements and clinical translation in efficient disease treatment.

A pro-death autophagy-based nanoplatform for enhancing antitumour efficacy with improved immune responses

Due to the pro-survival effect of mild autophagy, the therapeutic effect of chemo-immunotherapy is unsatisfactory. In addition, the adverse tumour microenvironment (TME), including the lack of antigen presentation, the deficiency of oxygen supply and immunosuppressive cells, results in immune escape and metastasis. Herein, a novel nanoplatform (CS-3BP/PA@DOX) based on the autophagy cascade is proposed for the first time to deliver the chemotherapeutic doxorubicin (DOX) and respiration inhibitor 3-bromopyruvic acid (3BP) to overcome the above obstacles. CS-3BP/PA@DOX exerts a synergistic therapeutic effect to initiate pro-death autophagy and facilitate the antigen presentation process by combining DOX chemotherapy and starvation therapy with 3BP. Additionally, CS-3BP/PA@DOX remodelled the immunosuppressive TME by alleviating hypoxia, damaging dense ECM, and downregulating PD-L1 to enhance antitumour immunity. 3BP was found to promote GSH depletion by inhibiting respiration for the first time, which reduces the chemical resistance of cancer and increases the sensitivity of cells to ROS, providing a new therapeutic direction of 3BP for antitumour treatment. Collectively, this study offers an opportunity to magnify pro-death autophagy, augment antitumour efficacy, facilitate anti-metastatic effects, and boost immune responses.

Dacarbazine-primed carbon quantum dots coated with breast cancer cell-derived exosomes for improved breast cancer therapy

Imprecise targeting of chemotherapeutic drugs often leads to severe toxicity during breast cancer therapy. To address this issue, we have devised a strategy to load dacarbazine (DC) into fucose-based carbon quantum dots (CQDs), which are subsequently coated with exosomes (Ex-DC@CQDs) derived from breast cancer cells. Nanoparticle tracking analysis and western blotting revealed that Ex-DC@CQDs retained the structural and functional characteristics of exosomes. We found that exosomes facilitated the transport of DC@CQDs to cancer cells via heparan sulfate proteoglycan (HSPG) receptors, followed by an augmented depolarization of the mitochondrial membrane potential, ROS generation, and induction of apoptosis leading to cell death. In vivo imaging and pharmacokinetic studies demonstrated enhanced antitumor targeting and efficacy compared to free DC which we attribute to an improved pharmacokinetic profile, a greater tumor accumulation via exosome-mediated- HSPG receptor-driven cell uptake, and sustained release of the Ex-DC@CQDs. Our findings may pave the way for the further development of biologically sourced nanocarriers for breast cancer targeting.

Nanocomposite fibers based on cellulose acetate loaded with fullerene for cancer therapy: preparation, characterization and in-vitro evaluation

The current prevalence of cancerous diseases necessitates the exploration of materials that can effectively treat these conditions while minimizing the occurrence of adverse side effects. This study aims to identify materials with the potential to inhibit the metastasis of cancerous diseases within the human body while concurrently serving as therapeutic agents for their treatment. A novel approach was employed to enhance the anti-cancer properties of electrospun cellulose fibers by incorporating fullerene nanoparticles (NPs) into cellulose acetate (CA) fibers, resulting in a composite material called Fullerene@CA. This development aimed at utilizing the anti-cancer properties of fullerenes for potential therapeutic applications. This process has been demonstrated in vitro against various types of cancer, and it was found that Fullerene@CA nanocomposite fibers displayed robust anticancer activity. Cancer cells (Caco-2, MDA-MB 231, and HepG-2 cells) were inhibited by 0.3 and 0.5 mg.g-1 fullerene doses by 58.62-62.87%, 47.86-56.43%, and 48.60-57.73%, respectively. The tested cancer cells shrink and lose their spindle shape due to morphological changes. The investigation of the prepared nanocomposite reveals its impact on various genes, such as BCL2, NF-KB, p53, Bax, and p21, highlighting the therapeutic compounds' effectiveness. The experimental results demonstrated that the incorporation of NPs into CA fibers resulted in a significant improvement in their anti-cancer efficacy. Therefore, it is suggested that these modified fibers could be utilized as a novel therapeutic approach for the treatment and prevention of cancer metastasis.

Surface modification strategies in translocating nano-vesicles across different barriers and the role of bio-vesicles in improving anticancer therapy

Nanovesicles and bio-vesicles (BVs) have emerged as promising tools to achieve targeted cancer therapy due to their ability to overcome many of the key challenges currently being faced with conventional chemotherapy. These challenges include the diverse and often complex pathophysiology involving the progression of cancer, as well as the various biological barriers that circumvent therapeutic molecules reaching their target site in optimum concentration. The scientific evidence suggests that surface-functionalized nanovesicles and BVs camouflaged nano-carriers (NCs) both can bypass the established biological barriers and facilitate fourth-generation targeting for the improved regimen of treatment. In this review, we intend to emphasize the role of surface-functionalized nanovesicles and BVs camouflaged NCs through various approaches that lead to an improved internalization to achieve improved and targeted oncotherapy. We have explored various strategies that have been employed to surface-functionalize and biologically modify these vesicles, including the use of biomolecule functionalized target ligands such as peptides, antibodies, and aptamers, as well as the targeting of specific receptors on cancer cells. Further, the utility of BVs, which are made from the membranes of cells such as mesenchymal stem cells (MSCs), white blood cells (WBCs), red blood cells (RBCs), platelets (PLTs) as well as cancer cells also been investigated. Lastly, we have discussed the translational challenges and limitations that these NCs can encounter and still need to be overcome in order to fully realize the potential of nanovesicles and BVs for targeted cancer therapy. The fundamental challenges that currently prevent successful cancer therapy and the necessity of novel delivery systems are in the offing.

Redox Homeostasis Disruptors Based on Metal-Phenolic Network Nanoparticles for Chemo/Chemodynamic Synergistic Tumor Therapy through Activating Apoptosis and Cuproptosis

The combination of chemo/chemodynamic therapy is a promising strategy for improving antitumor efficacy. Herein, metal-phenolic network nanoparticles (NPs) self-assembled from copper ions and gallic acid (Cu-GA) are developed to evoke apoptosis and cuproptosis for synergistic chemo/chemodynamic therapy. The Cu-GA NPs are biodegraded in response to the highly expressed glutathione (GSH) in tumor cells, resulting in the simultaneous release of Cu+ and GA. The intracellular GSH content is dramatically reduced by the released GA, rendering the tumor cells incapable of scavenging reactive oxygen species (ROS) and more susceptible to cuproptosis. Meanwhile, ROS levels within the tumor cells are significantly increased by the Fenton-like reaction of released Cu+ , which disrupts redox homeostasis and achieves apoptosis-related chemodynamic therapy. Moreover, massive accumulation of Cu+ in the tumor cells further induces aggregation of lipoylated dihydrolipoamide S-acetyltransferase and downregulation of iron-sulfur cluster protein, activating cuproptosis to enhance the antitumor efficacy of Cu-GA NPs. The experiments in vivo further demonstrate that Cu-GA NPs exhibited the excellent biosafety and superior antitumor capacity, which can efficiently inhibit the growth of tumors due to the activation by the tumor specific GSH and hydrogen peroxide. These Cu-based metal-phenolic network NPs provide a potential strategy to build up efficient and safe cancer therapy.

Dysregulated Signalling Pathways Driving Anticancer Drug Resistance

One of the leading causes of death worldwide, in both men and women, is cancer. Despite the significant development in therapeutic strategies, the inevitable emergence of drug resistance limits the success and impedes the curative outcome. Intrinsic and acquired resistance are common mechanisms responsible for cancer relapse. Several factors crucially regulate tumourigenesis and resistance, including physical barriers, tumour microenvironment (TME), heterogeneity, genetic and epigenetic alterations, the immune system, tumour burden, growth kinetics and undruggable targets. Moreover, transforming growth factor-beta (TGF-β), Notch, epidermal growth factor receptor (EGFR), integrin-extracellular matrix (ECM), nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB), phosphoinositol-3-kinase/protein kinase B/mammalian target of rapamycin (PI3K/Akt/mTOR), wingless-related integration site (Wnt/β-catenin), Janus kinase/signal transducers and activators of transcription (JAK/STAT) and RAS/RAF/mitogen-activated protein kinase (MAPK) signalling pathways are some of the key players that have a pivotal role in drug resistance mechanisms. To guide future cancer treatments and improve results, a deeper comprehension of drug resistance pathways is necessary. This review covers both intrinsic and acquired resistance and gives a comprehensive overview of recent research on mechanisms that enable cancer cells to bypass barriers put up by treatments, and, like "satellite navigation", find alternative routes by which to carry on their "journey" to cancer progression.

A Comprehensive Review of Inorganic Sonosensitizers for Sonodynamic Therapy

Sonodynamic therapy (SDT) is an emerging non-invasive cancer treatment method in the field of nanomedicine, which has the advantages of deep penetration, good therapeutic efficacy, and minimal damage to normal tissues. Sonosensitizers play a crucial role in the process of SDT, as their structure and properties directly determine the treatment outcome. Inorganic sonosensitizers, with their high stability and longer circulation time in the human body, have great potential in SDT. In this review, the possible mechanisms of SDT including the ultrasonic cavitation, reactive oxygen species generation, and activation of immunity are briefly discussed. Then, the latest research progress on inorganic sonosensitizers is systematically summarized. Subsequently, strategies for optimizing treatment efficacy are introduced, including combination therapy and image-guided therapy. The challenges and future prospects of sonodynamic therapy are discussed. It is hoped that this review will provide some guidance for the screening of inorganic sonosensitizers.

Crosslinked and PEGylated Pectin Chitosan Nanoparticles for Delivery of Phytic Acid to Colon

Polysaccharide-based nanoparticles (NPs) such as pectin/ chitosan (PN/CN) had always been of greatest interest because of their excellent solubility, biocompatibility, and higher suitability for oral drug delivery. This study employed blending-crosslinking of polymers (PN&CN) followed by emulsification-solvent evaporation to prepare and compare two sets of PEGylated NPs to deliver phytic acid (IP6) to colon orally as it has potential to manage colon cancer but fails to reach colon when ingested in pure form. The first set was crosslinked with Glutaraldehyde (GE) (GE*PN-CN-NPs) while the second set was crosslinked with sodium tripolyphosphate (TPP) (TPP*PN-CN-NPs). IP6-loaded-GE/TPP*PN-CN-NPs were optimized using a central composite design. Developed TPP*PN-CN-NPs had a smaller size (210.6±7.93nm) than GE*PN-CN-NPs (557.2±5.027nm). Prepared NPs showed <12% IP6 release at pH 1.2 whereas >80% release was observed at pH 7.4. Further, NPs were explored for cytocompatibility in J774.2 cell lines, cytotoxicity, and cellular uptake in HT-29 and DLD-1 cell lines. While exhibiting substantial cytotoxicity and cellular uptake in HT-29 and DLD-1, the NPs were deemedsafe in J774.2. The PEGylated-TPP*PN-CN-NPs showed time-dependent uptake in J774.2 cell lines. Conclusively, the employed NP development method successfully delivered IP6 to colon and may also open avenues for the oral delivery of other drugs to colon.

Exosomal circular RNAs: A chief culprit in cancer chemotherapy resistance

Chemotherapy is one of the primary treatments for malignant tumors. However, the acquired drug resistance hinders clinical efficacy and leads to treatment failure in most patients. Exosomes are cell-derived vesicles with a diameter of 30-150 nm carrying and delivering substances such as DNAs, RNAs, lipids, and proteins for cellular communication in tumor development. Circular RNAs (circRNAs) present covalently closed-loop RNA structures, which regulate tumor cell proliferation, apoptosis, and metastasis by controlling different genes and signaling pathways. CircRNAs are abundant and stably expressed in exosomes. Recent studies have shown that they play critical roles in chemotherapy resistance in various cancers. In this review, we summarized the origin of exosomes and discussed the regulation mechanism of exosomal circRNAs in cancer drug resistance.

Development of Polymersomes Co-Delivering Doxorubicin and Melittin to Overcome Multidrug Resistance

Multidrug resistance (MDR) is one of the major barriers in chemotherapy. It is often related to the overexpression of efflux receptors such as P-glycoprotein (P-gp). Overexpressed efflux receptors inhibit chemotherapeutic efficacy by pumping out intracellularly delivered anticancer drugs. In P-gp-mediated MDR-related pathways, PI3K/Akt and NF-kB pathways are commonly activated signaling pathways, but these pathways are downregulated by melittin, a main component of bee venom. In this study, a polymersome based on a poly (lactic acid) (PLA)-hyaluronic acid (HA) (20k-10k) di-block copolymer and encapsulating melittin and doxorubicin was developed to overcome anticancer resistance and enhance chemotherapeutic efficacy. Through the simultaneous delivery of doxorubicin and melittin, PI3K/Akt and NF-κB pathways could be effectively inhibited, thereby downregulating P-gp and successfully enhancing chemotherapeutic efficacy. In conclusion, a polymersome carrying an anticancer drug and melittin could overcome MDR by regulating P-gp overexpression pathways.

Role of hypoxia in the tumor microenvironment and targeted therapy

Tumor microenvironment (TME), which is characterized by hypoxia, widely exists in solid tumors. As a current research hotspot in the TME, hypoxia is expected to become a key element to break through the bottleneck of tumor treatment. More and more research results show that a variety of biological behaviors of tumor cells are affected by many factors in TME which are closely related to hypoxia. In order to inhibiting the immune response in TME, hypoxia plays an important role in tumor cell metabolism and anti-apoptosis. Therefore, exploring the molecular mechanism of hypoxia mediated malignant tumor behavior and therapeutic targets is expected to provide new ideas for anti-tumor therapy. In this review, we discussed the effects of hypoxia on tumor behavior and its interaction with TME from the perspectives of immune cells, cell metabolism, oxidative stress and hypoxia inducible factor (HIF), and listed the therapeutic targets or signal pathways found so far. Finally, we summarize the current therapies targeting hypoxia, such as glycolysis inhibitors, anti-angiogenesis drugs, HIF inhibitors, hypoxia-activated prodrugs, and hyperbaric medicine.

Nanomedicines for Overcoming Cancer Drug Resistance

Clinically, cancer drug resistance to chemotherapy, targeted therapy or immunotherapy remains the main impediment towards curative cancer therapy, which leads directly to treatment failure along with extended hospital stays, increased medical costs and high mortality. Therefore, increasing attention has been paid to nanotechnology-based delivery systems for overcoming drug resistance in cancer. In this respect, novel tumor-targeting nanomedicines offer fairly effective therapeutic strategies for surmounting the various limitations of chemotherapy, targeted therapy and immunotherapy, enabling more precise cancer treatment, more convenient monitoring of treatment agents, as well as surmounting cancer drug resistance, including multidrug resistance (MDR). Nanotechnology-based delivery systems, including liposomes, polymer micelles, nanoparticles (NPs), and DNA nanostructures, enable a large number of properly designed therapeutic nanomedicines. In this paper, we review the different mechanisms of cancer drug resistance to chemotherapy, targeted therapy and immunotherapy, and discuss the latest developments in nanomedicines for overcoming cancer drug resistance.