Trends in targeting Bcl-2 anti-apoptotic proteins for cancer treatment

Enhanced apoptosis in damaged laminar tissue of acute laminitis induced by oligofructose overload in dairy cows

Dairy cow laminitis leads to massive financial losses and animal health issues in the worldwide dairy sector. Apoptosis may be an important factor in the epidermal attachment failure. This study explored the laminar tissue apoptotic-related gene and protein status with oligofructose (OF)-induced laminitis in dairy cows. Twelve clinically healthy, non-pregnant Chinese Holstein cows were randomly divided into two groups of six cows each: the control group and the oligofructose overload group (OF group), respectively. At 0 h, 17 g/kg BW of OF dissolved in 20 mL/kg BW of warm deionized water was gavaged to the OF dairy cows through a stomach tube, while the control cows were given the same dose of deionized water in the same way. After 72 h, laminar tissue samples in both groups were collected to express genes and proteins. Compared with the control cows, the gene expression of Bcl2 significantly reduced in the OF cows laminar tissue. The gene expression of Bax and P53 significantly enhanced in the laminar tissue of OF cows compared to the control cows. The expression of Bcl2 protein significantly decreased, whereas the expression of Bax and Bif1, caspase3, caspase8, and caspase9/9p proteins significantly increased in the OF cows' laminar tissues than in the control cows. However, the distribution of Bax and P53 proteins significantly enhanced in the OF cows' laminar tissues relative to the control cows. In conclusion, imbalanced gene and protein status may represent the primary cause of the epidermal attachment failure, which confirmed the increased apoptosis in laminar tissue of sick cows.

Combinatorial screen with apoptosis pathway targeted agents alrizomadlin, pelcitoclax, and dasminapant in multi-cell type tumor spheroids

Apoptosis, or programmed cell death, plays a critical role in maintaining tissue homeostasis by eliminating damaged or abnormal cells. Dysregulation of apoptosis pathways is a hallmark of cancer, allowing malignant cells to evade cell death and proliferate uncontrollably. Targeting apoptosis pathways has emerged as a promising therapeutic strategy in cancer treatment, aiming to restore the balance between cell survival and death. The MDM2 inhibitor alrizomadlin, the Bcl-2/Bcl-xL inhibitor pelcitoclax, and the IAP family inhibitor dasminapant were evaluated both individually and in combinations with standard of care and investigational anticancer small molecules in a spheroid model of solid tumors. The multi-cell type tumor spheroids were grown from human endothelial cells and mesenchymal stem cells combined with human malignant cells that were either established or patient-derived cell lines from the NCI Patient-Derived Models Repository. The malignant cell lines were derived from a range of solid tumors including uterine carcinosarcoma, synovial sarcoma, rhabdomyosarcoma, soft tissue sarcoma, malignant fibrous histiocytoma, malignant peripheral nerve sheath tumor (MPNST), pancreas, ovary, colon, breast, and small cell lung cancer. Interactions were observed from combinations of the apoptosis pathway targeted agents. Additionally, interactions were observed from combinations of the apoptosis pathway targeted agents with other agents, including PARP inhibitors, the XPO1 inhibitor eltanexor, and the PI3K inhibitor copanlisib. Enhanced activity was also observed from combinations of the apoptosis pathway targeted agents with MAPK pathway targeted agents, including the MEK inhibitor cobimetinib as well as adagrasib and MRTX1133, which specifically target the KRAS G12C and G12D variants, respectively.

Structurally diverse sesquiterpenes with anti-leukemia activity from the rare medicinal plant Liriodendron chinense

A further phytochemical investigation on the branches and leaves of Liriodendron chinense, a rare medicinal and ornamental plant endemic to China, yielded thirty-four sesquiterpenes with diverse skeletons. The isolated compounds comprise 12 new naturally occurring sesquiterpenoids (1-12) and 22 known analogues (13-34). The new structures were elucidated by spectroscopic data analyses, and their absolute configurations (except for 10) were determined by electronic circular dichroism spectra, quantum-chemical calculations, and X-ray crystallography. Among them, liriochinolide A (1) is a rare chlorine-substituted germacrane-type sesquiterpenoid from the terrestrial plants. Bioassay evaluations revealed that most of the isolates exhibited remarkable cytotoxicity against three human leukemia cell lines (MV-4-11, HL-60 and Raji), with IC50 values ranging from 2.27 to 9.69 μM. Further exploration of anti-leukemia mechanism demonstrated that the bioactive compounds 5, 8, and 18 significantly induced the cell apoptosis, which was associated with down-regulation of the anti-apoptotic proteins BCL-2 and MCL-1.

Chemical dissection of selective myeloid leukemia-1 inhibitors: How they were found and evolved

Myeloid cell leukemia-1 (MCL-1), a key anti-apoptotic protein within the BCL-2 family, is essential in regulating cell survival, particularly in cancer, where its overexpression is often linked to therapeutic resistance. This review begins with an overview of BCL-2-mediated apoptosis, highlighting the pivotal role of MCL-1 in cellular homeostasis. We then focus on the structure and function of MCL-1, elucidating how its unique structural features contribute to its function and interaction with pro-apoptotic proteins. The core of this review is a detailed structural analysis of selective MCL-1 inhibitors, tracing their development from initial discovery to stepwise optimization. We explore various classes of inhibitors, including those with distinct core structures, covalent inhibitors that reversibly/irreversibly bind to MCL-1, and innovative approaches such as metal-based inhibitors and proteolysis-targeting chimeras (PROTACs). The structural evolution of these inhibitors is discussed, with particular emphasis on the modifications that have enhanced their selectivity, potency, and pharmacokinetic profiles. Additionally, we summarize the synergistic potential of MCL-1 inhibitors when used in combination with other therapeutic agents, emphasizing their role in overcoming drug resistance. The review concludes with a discussion of current challenges in MCL-1 modulation and future perspectives, proposing alternative strategies for targeting this critical protein for cancer therapy.

Discovery and development of thiazolidine-2,4-dione derivatives as Bcl-2/Mcl-1 dual inhibitors

Increasing the levels of antiapoptotic Bcl-2 proteins is an important way that cancer cells utilize to get out of apoptosis, underscoring their significance as promising targets for anticancer therapies. Lately, a primary compound 1 bearing thiazolidine-2,4-dione was discovered to exhibit comparable Mcl-1 inhibitory activity in comparison to WL-276. Herein, thirty-nine thiazolidine-2,4-dione analogs were yielded through incorporating different biphenyl moieties (R1), amino acid side chains (R2) and sulfonamides (R3) on 1. The findings indicated that certain compounds exhibited favorable inhibitory effects against Bcl-2/Mcl-1, while demonstrating limited or negligible binding affinity towards Bcl-xL. In particular, compounds 16 and 20 exhibited greater Bcl-2/Mcl-1 inhibition compared to AT-101, WL-276 and 1. Moreover, they demonstrated notable antiproliferative effects and significantly induced apoptosis in U937 cells. The western blot and co-immunoprecipitation assays confirmed that 20 could induce alterations in the expression of apoptosis-associated proteins to result in apoptosis through on-target Bcl-2 and Mcl-1 inhibition. In addition, 20 exhibited favorable stability profiles in both rat plasma and rat liver microsomes. In total, 20 could be used as a promising compound to discover Bcl-2/Mcl-1 dual inhibitors with favorable therapeutic properties.

Rationally designed catalytic nanoplatform for enhanced chemoimmunotherapy via deploying endogenous plus exogenous copper and remodeling tumor microenvironment

Chemodynamic therapy represents a novel tumor therapeutic modality via triggering catalytic reactions in tumors to yield highly toxic reactive oxygen species (ROS). Nevertheless, low efficiency catalytic ability, potential systemic toxicity and inefficient tumor targeting, have hindered the efficacy of chemodynamic therapy. Herein, a rationally designed catalytic nanoplatform, composed of folate acid conjugated liposomes loaded with copper peroxide (CP) and chloroquine (CQ; a clinical drug) (denoted as CC@LPF), could power maximal tumor cytotoxicity, mechanistically via maneuvering endogenous and exogenous copper for a highly efficient catalytic reaction. Despite a massive autophagosome accumulation elicited by CP-powered autophagic initiation and CQ-induced autolysosomal blockage, the robust ROS, but not aberrant autophagy, underlies the synergistic tumor inhibition. Otherwise, this combined mode also elicits an early onset, above all, long-term high-level existence of immunogenic cell death markers, associated with ROS and aberrant autophagy -triggered endoplasmic reticulum stress. Besides, CC@LPF, with tumor targeting capability and selective tumor cytotoxicity, could elicit intratumor dendritic cells (mainly attributed to CQ) and tumor infiltrating CD8+ T cells, upon combining with PD-L1 therapeutic antibody, further induce significant anti-tumor effect. Collectively, the rationally designed nanoplatform, CC@LPF, could enhance tumor chemoimmunotherapy via deploying endogenous plus exogenous copper and remodeling tumor microenvironment.

Apoptotic signaling pathways in bone metastatic lung cancer: a comprehensive analysis

This review provides a comprehensive analysis of apoptotic signaling pathways in the context of bone metastatic lung cancer, emphasizing the intricate molecular mechanisms and microenvironmental influences. Beginning with an overview of apoptosis in cancer, the paper explores the specific molecular characteristics of bone metastatic lung cancer, highlighting alterations in apoptotic pathways. Focused discussions delve into key apoptotic signaling pathways, including the intrinsic and extrinsic pathways, and the roles of critical molecular players such as Bcl-2 family proteins and caspases. Microenvironmental factors, such as the tumor microenvironment, extracellular matrix interactions, and immune cell involvement, are examined in depth. The review also addresses experimental approaches and techniques employed in studying apoptotic signaling, paving the way for a discussion on current therapeutic strategies, their limitations, and future prospects. This synthesis contributes a holistic understanding of apoptosis in bone metastatic lung cancer, offering insights for potential therapeutic advancements.

Directly targeting BAX for drug discovery: Therapeutic opportunities and challenges

For over two decades, the development of B-cell lymphoma-2 (Bcl-2) family therapeutics has primarily focused on anti-apoptotic proteins, resulting in the first-in-class drugs called BH3 mimetics, especially for Bcl-2 inhibitor Venetoclax. The pro-apoptotic protein Bcl-2-associated X protein (BAX) plays a crucial role as the executioner protein of the mitochondrial regulated cell death, contributing to organismal development, tissue homeostasis, and immunity. The dysregulation of BAX is closely associated with the onset and progression of diseases characterized by pathologic cell survival or death, such as cancer, neurodegeneration, and heart failure. In addition to conducting thorough investigations into the physiological modulation of BAX, research on the regulatory mechanisms of small molecules identified through biochemical screening approaches has prompted the identification of functional and potentially druggable binding sites on BAX, as well as diverse all-molecule BAX modulators. This review presents recent advancements in elucidating the physiological and pharmacological modulation of BAX and in identifying potentially druggable binding sites on BAX. Furthermore, it highlights the structural and mechanistic insights into small-molecule modulators targeting diverse binding surfaces or conformations of BAX, offering a promising avenue for developing next-generation apoptosis modulators to treat a wide range of diseases associated with dysregulated cell death by directly targeting BAX.

Inhibitory effect of miR-377 on the proliferative and invasive behaviors of prostate cancer cells through the modulation of MYC mRNA via its interaction with BCL-2/Bax, PTEN, and CDK4

The MYC gene is a regulatory and proto-oncogenic gene that is overexpressed in the majority of prostate cancers (PCa). Numerous studies have indicated that aberrant expression of microRNAs is involved in the initiation and progression of prostate cancer. In this investigation, we assessed the impact of miR-377 on MYC through luciferase assay. Real-time PCR was employed to determine whether miR-377 could reduce the levels of MYC mRNA in transfected PCa cell lines (PC-3 and DU145) and change in the mRNA levels of BCL-2/Bax, PTEN, and CDK4 as a consequence of MYC downregulation. Moreover, we analyzed the effects of miR-377 on apoptosis, proliferation, cell cycle, and wound healing. Our findings demonstrate that miR-377 effectively targets MYC mRNA, as confirmed by luciferase assay and Real-time PCR. We observed a significant reduction in BCL-2 and CDK4 expression, along with an increase in Bax and PTEN, in prostate cancer cell lines upon MYC suppression. Additionally, elevated levels of miR-377 in PCa cell lines induced apoptosis, inhibited proliferation and migration, and arrested the cell cycle. Taken together, these results unveil the inhibitory role of miR-377 in MYC function within PCa, thereby suggesting its potential as a therapeutic target for the treatment of this malignancy.

Metformin and buparlisib synergistically induce apoptosis of non-small lung cancer (NSCLC) cells via Akt/FoxO3a/Puma axis

Non-small cell lung cancer (NSCLC) is a global health issue lacking effective treatments. Buparlisib is a pan-PI3K inhibitor that shows promising clinical results in treating NSCLC. However, chemoresistance is inevitable and hampers the application of buparlisib. Studies show that a combination of phytochemicals and chemotherapeutics enhances its effectiveness. Here, we evaluated the role of metformin, an agent with multiple pharmacological properties, in enhancing the anti-tumour activities of buparlisib against NSCLC cells. Our results showed that metformin and buparlisib synergistically inhibited cell viability, migration, and invasion of NSCLC cells. In addition, co-treatment of metformin and buparlisib also induced cell cycle arrest and cell death in NSCLC cells. Mechanistically, metformin and buparlisib repressed Mcl-1 and upregulated Puma in NSCLC cells in a p53-independent manner. Moreover, they inhibited the PI3K/Akt signalling pathway, leading to activation of the FoxO3a/Puma signalling in NSCLC cells. Our findings suggest that combined treatment of metformin and buparlisib might provide a promising strategy for treating NSCLC.

Role of YY1 in the Regulation of Anti-Apoptotic Gene Products in Drug-Resistant Cancer Cells

Cancer is a leading cause of death among the various diseases encountered in humans. Cancer is not a single entity and consists of numerous different types and subtypes that require various treatment regimens. In the last decade, several milestones in cancer treatments were accomplished, such as specific targeting agents or revitalizing the dormant anti-tumor immune response. These milestones have resulted in significant positive clinical responses as well as tumor regression and the prolongation of survival in subsets of cancer patients. Hence, in non-responding patients and non-responding relapsed patients, cancers develop intrinsic mechanisms of resistance to cell death via the overexpression of anti-apoptotic gene products. In parallel, the majority of resistant cancers have been reported to overexpress a transcription factor, Yin Yang 1 (YY1), which regulates the chemo-immuno-resistance of cancer cells to therapeutic anticancer cytotoxic agents. The relationship between the overexpression of YY1 and several anti-apoptotic gene products, such as B-cell lymphoma 2 protein (Bcl-2), B-cell lymphoma extra-large (Bcl-xL), myeloid cell leukemia 1 (Mcl-1) and survivin, is investigated in this paper. The findings demonstrate that these anti-apoptotic gene products are regulated, in part, by YY1 at the transcriptional, epigenetic, post-transcriptional and translational levels. While targeting each of the anti-apoptotic gene products individually has been examined and clinically tested for some, this targeting strategy is not effective due to compensation by other overexpressed anti-apoptotic gene products. In contrast, targeting YY1 directly, through small interfering RNAs (siRNAs), gene editing or small molecule inhibitors, can be therapeutically more effective and generalized in YY1-overexpressed resistant cancers.

Proteolysis-targeting chimeras in biotherapeutics: Current trends and future applications

The success of inhibitor-based therapeutics is largely constrained by the acquisition of therapeutic resistance, which is partially driven by the undruggable proteome. The emergence of proteolysis targeting chimera (PROTAC) technology, designed for degrading proteins involved in specific biological processes, might provide a novel framework for solving the above constraint. A heterobifunctional PROTAC molecule could structurally connect an E3 ubiquitin ligase ligand with a protein of interest (POI)-binding ligand by chemical linkers. Such technology would result in the degradation of the targeted protein via the ubiquitin-proteasome system (UPS), opening up a novel way of selectively inhibiting undruggable proteins. Herein, we will highlight the advantages of PROTAC technology and summarize the current understanding of the potential mechanisms involved in biotherapeutics, with a particular focus on its application and development where therapeutic benefits over classical small-molecule inhibitors have been achieved. Finally, we discuss how this technology can contribute to developing biotherapeutic drugs, such as antivirals against infectious diseases, for use in clinical practices.

BCL-G: 20 years of research on a non-typical protein from the BCL-2 family

Proteins from the BCL-2 family control cell survival and apoptosis in health and disease, and regulate apoptosis-unrelated cellular processes. BCL-Gonad (BCL-G, also known as BCL2-like 14) is a non-typical protein of the family as its long isoform (BCL-G_L) consists of BH2 and BH3 domains without the BH1 motif. BCL-G is predominantly expressed in normal testes and different organs of the gastrointestinal tract. The complexity of regulatory mechanisms of BCL-G expression and post-translational modifications suggests that BCL-G may play distinct roles in different types of cells and disorders. While several genetic alterations of BCL2L14 have been reported, gene deletions and amplifications prevail, which is also confirmed by the analysis of sequencing data for different types of cancer. Although the studies validating the phenotypic consequences of genetic manipulations of BCL-G are limited, the role of BCL-G in apoptosis has been undermined. Recent studies using gene-perturbation approaches have revealed apoptosis-unrelated functions of BCL-G in intracellular trafficking, immunomodulation, and regulation of the mucin scaffolding network. These studies were, however, limited mainly to the role of BCL-G in the gastrointestinal tract. Therefore, further efforts using state-of-the-art methods and various types of cells are required to find out more about BCL-G activities. Deciphering the isoform-specific functions of BCL-G and the BCL-G interactome may result in the designing of novel therapeutic approaches, in which BCL-G activity will be either imitated using small-molecule BH3 mimetics or inhibited to counteract BCL-G upregulation. This review summarizes two decades of research on BCL-G.

Water-soluble copper(II) 5-fluorouracil complexes bearing polypyridyl co-ligands: synthesis, structures and anticancer activity

Five newly synthesized copper(II) 5-fluorouracil (5-FU) complexes of polypyridyl co-ligands with good solubility in water, namely [CuCl(5-FU)(bpy)(DMSO)] (1), [Cu(5-FU)(phen)₂](5-FU)·4H₂O (2), [Cu(5-FU)(dpya)₂](NO₃)·2.5H₂O (3), [Cu(5-FU)(NO₃)(bpyma)]·H₂O (4) and [CuCl(5-FU)(terpy)] (5) (bpy = 2,2'-bipyridine, phen = 1,10-phenanthroline, dpya = 2,2'-dipyridylamine, bpyma = bis(2-pyridylmethyl)amine and terpy = 2,2';6',2''-terpyridine), were characterized by elemental analysis and a number of spectrometric methods. The structures of complexes 1-5 were determined by X-ray crystallography and the copper(II) ions were five coordinate. Cytotoxic activity of the complexes in four human cancer cell lines, A549 (lung carcinoma), MDA-MB-231 (breast carcinoma), HCT116 (colon carcinoma) and DU145 (prostate carcinoma), and a normal cell line, BEAS-2B (human lung epithelial), was determined by SRB assay and compared with that of 5-FU and cisplatin. The complexation of 5-FU together with polypyridyl ligands resulted in a significant increase in the cytotoxicity of the complexes, with complex 2 exhibiting the highest anticancer potency against all the cell lines, with HCT116 being the most sensitive. The mode of action of cell death for 2 was investigated using morphological imaging and cytometric analyses, including the capacity for induction of apoptosis, generation of reactive oxygen species, mitochondrial dysfunction and DNA damage.

Development of an efficient method for separation and purification of cordycepin from liquid fermentation of Cordyceps militaris and analysis of cordycepin antitumor activity

Cordycepin (3 '-deoxyadenosine) is the main active component of Cordyceps militaris, which is a chemical marker for quality detection of Cordyceps militaris and has important medicinal development value. Existing methods for obtaining cordycepin are complex and costly. In this study, an economical and simple method for separation and purification of cordycepin from Cordyceps militaris fermentation liquid through physical crystallization was explored. First, lyophilized powdered fermentation liquid (LPFL) and pure methanol (1 g/100 mL, w/v) were mixed, and then repeatedly dissolved and crystallized until the precipitation was white. Purified product was obtained by freeze-drying the precipitate. The substance was determined to be cordycepin by high performance liquid chromatography, mass spectrometry and infrared spectroscopy, and the purity was 94.26%. Compared with the existing methods, this method is simple and low cost. In addition, the functional activity of cordycepin was determined by in vitro test. The results exhibited that cordycepin caused death and morphological changes in human colon cancer Caco-2 cells, and significantly inhibited the proliferation of Caco-2 cells, with a half-maximal inhibitory concentration (IC₅₀) of 107.2 μg/mL. Cordycepin could induce early apoptosis of Caco-2 and caused cell cycle arrest in the G2 phase. Caco-2 cell apoptosis and cell cycle arrest showed dose dependence to cordycepin over a certain range. These results improved cordycepin purification method, provided insights into the mechanism of cordycepin in cancer inhibition, and would provide important reference for further development and clinical application of cordycepin.

Apoptotic Mechanisms of Quercetin in Liver Cancer: Recent Trends and Advancements

Due to rising incidence rates of liver cancer and worries about the toxicity of current chemotherapeutic medicines, the hunt for further alternative methods to treat this malignancy has escalated. Compared to chemotherapy, quercetin, a flavonoid, is relatively less harmful to normal cells and is regarded as an excellent free-radical scavenger. Apoptotic cell death of cancer cells caused by quercetin has been demonstrated by many prior studies. It is present in many fruits, vegetables, and herbs. Quercetin targets apoptosis, by upregulating Bax, caspase-3, and p21 while downregulating Akt, PLK-1, cyclin-B1, cyclin-A, CDC-2, CDK-2, and Bcl-2. Additionally, it has been reported to increase STAT3 protein degradation in liver cancer cells while decreasing STAT3 activation. Quercetin has a potential future in chemoprevention, based on substantial research on its anticancer effects. The current review discusses quercetin's mechanisms of action, nanodelivery strategies, and other potential cellular effects in liver cancer.

Optimization of BAX trigger site activator BTSA1 with improved antitumor potency and in vitro ADMET properties

Direct activation of the pro-apoptotic protein BAX represents a potential therapeutic strategy to trigger apoptosis in cancer. Herein, structural optimization of the reported BAX trigger site activator BTSA1 turned out into a series of pyrazolone derivatives, where compound 6d exhibited significantly enhanced antiproliferative effects and apoptosis induction ability compared to BTSA1. Mechanism of action studies revealed that compound 6d could initiate the BAX activation cascade, promoting BAX insertion into mitochondrial membranes and activating MOMP, ultimately leading to the release of cytochrome c and apoptosis. Furthermore, 6d showed significantly improved in vitro stability and CYPs profile compared to BTSA1. This work may lay a foundation to develop potent BAX trigger site activators for the treatment of BAX-expressing malignancies.

N-Propargylic β-enaminones in breast cancer cells: Cytotoxicity, apoptosis, and cell cycle analyses

Breast cancer is one of the most common cancers worldwide and the discovery of new cytotoxic agents is needed. Enaminones are regarded to be a significant structural motif that is found in a variety of pharmacologically active compounds however the number of studies investigating the anticancer activities of N-propargylic β-enaminones (NPEs) is limited. Herein we investigated the potential cytotoxic and apoptotic effects of 23 different NPEs (1-23) on human breast cancer cells. Cytotoxicity was evaluated via MTT assay. Apoptotic cell death and cell cycle distributions were investigated by flow cytometry. CM-H2DCFDA dye was used to evaluate cellular ROS levels. Expression levels of Bcl-2, Bax, p21, and Cyclin D1 were measured by quantitative real-time PCR. ADME properties were calculated using the ADMET 2.0 tool. NPEs 4, 9, 16, and 21 showed selective cytotoxic activity against breast cancer cells with SI values >2. NPEs induced apoptosis and caused significant changes in Bcl-2 and Bax mRNA levels. The cell cycle was arrested at the G0/G1 phase and levels of p21 and Cyclin D1 were upregulated in both breast cancer cells. ROS levels were significantly increased by NPEs, suggesting that the cytotoxic and apoptotic effects of NPEs were mediated by ROS. ADME analysis revealed that NPEs showed favorable distributions in both breast cancer cell lines, meaning good lipophilicity values, low unfractionated values, and high bioavailability. Therefore, these potential anticancer compounds should be further validated by in vivo studies for their appropriate function in human health with a safety profile, and a comprehensive drug interaction study should be performed.

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.