Multiple drug resistance mechanisms in cancer. Mol Biotechnol. 2010;46:308-316. [PMID: 20717753 DOI: 10.1007/s12033-010-9321-2]

Anticancer perspectives of monocarbonyl analogs of curcumin: A decade (2014-2024) review

Monocarbonyl analogs of curcumin (MACs) represent structurally modified versions of curcumin. The existing literature indicates that MACs exhibit enhanced anticancer properties compared with curcumin. Numerous research articles in recent years have emphasized the significance of MACs as effective anticancer agents. This review focuses on the latest advances in the anticancer potential of MACs, from 2014 to 2024, including discussions on their mechanism of action, structure-activity relationship (SAR), and in silico molecular docking studies.

Affinity-directed substrate/H+-antiport by a MATE transporter

Multidrug and toxin extrusion (MATE) family transporters excrete toxic compounds coupled to Na+/H+ influx. Although structures of MATE transporters are available, the mechanism by which substrate export is coupled to ion influx remains unknown. To address this issue, we conducted a structural analysis of Pyrococcus furiosus MATE (PfMATE) using solution nuclear magnetic resonance (NMR). The NMR analysis, along with thorough substitutions of all non-exposed acidic residues, confirmed that PfMATE is under an equilibrium between inward-facing (IF) and outward-facing (OF) conformations, dictated by the Glu163 protonation. Importantly, we found that only the IF conformation exhibits a mid-μM affinity for substrate recognition. In contrast, the OF conformation exhibited only weak mM substrate affinity, suitable for releasing substrate to the extracellular side. These results indicate that PfMATE is an affinity-directed H+ antiporter where substrates selectively bind to the protonated IF conformation in the equilibrium, and subsequent proton release mechanistically ensures H+-coupled substrate excretion by the transporter.

Nanomedicine-induced cell pyroptosis to enhance antitumor immunotherapy

Immunotherapy is a therapeutic modality designed to elicit or augment an immune response against malignancies. Despite the immune system's ability to detect and eradicate neoplastic cells, certain neoplastic cells can elude immune surveillance and elimination through diverse mechanisms. Therefore, antitumor immunotherapy has emerged as a propitious strategy. Pyroptosis, a type of programmed cell death (PCD) regulated by Gasdermin (GSDM), is associated with cytomembrane rupture due to continuous cell expansion, which results in the release of cellular contents that can trigger robust inflammatory and immune responses. The field of nanomedicine has made promising progress, enabling the application of nanotechnology to enhance the effectiveness and specificity of cancer therapy by potentiating, enabling, or augmenting pyroptosis. In this review, we comprehensively examine the paradigms underlying antitumor immunity, particularly paradigms related to nanotherapeutics combined with pyroptosis; these treatments include chemotherapy (CT), hyperthermia therapy, photodynamic therapy (PDT), chemodynamic therapy (CDT), ion-interference therapy (IIT), biomimetic therapy, and combination therapy. Furthermore, we thoroughly discuss the coordinated mechanisms that regulate these paradigms. This review is expected to enhance the understanding of the interplay between pyroptosis and antitumor immunotherapy, broaden the utilization of diverse nanomaterials in pyroptosis-based antitumor immunotherapy, and facilitate advancements in clinical tumor therapy.

Reversing Anticancer Drug Resistance by Synergistic Combination of Chemotherapeutics and Membranolytic Antitumor β-Peptide Polymer

Multidrug resistance is the main obstacle to cancer chemotherapy. Overexpression of drug efflux pumps causes excessive drug efflux from cancer cells, ultimately leading to drug resistance. Hereby, we raise an effective strategy to overcome multidrug resistance using a synergistic combination of membranolytic antitumor β-peptide polymer and chemotherapy drugs. This membrane-active β-peptide polymer promotes the transmembrane transport of chemotherapeutic drugs by increasing membrane permeability and enhances the activity of chemotherapy drugs against multidrug-resistant cancer cells. As a proof-of-concept demonstration, the synergistic combination of β-peptide polymer and doxorubicin (DOX) is substantially more effective than DOX alone against drug-resistant cancer both in vitro and in vivo. Notably, the synergistic combination maintains a potent anticancer activity after continuous use. Collectively, this combination therapy using membrane lytic β-peptide polymer appears to be an effective strategy to reverse anticancer drug resistance.

Overcoming multi drug resistance mediated by ABC transporters by a novel acetogenin- annonacin from Annona muricata L

ETHNOPHARMACOLOGICAL RELEVANCE

Multi-Drug Resistance (MDR), mediated by P-glycoprotein (P-gp) is one of the barriers to successful chemotherapy in colon cancer patients. Annona muricata L. (A.muricata), commonly known as soursop/Graviola, is a medicinal plant that has been traditionally used in treating diverse diseases including cancer. Phytochemicals of A.muricata (Annonaceous Acetogenins-AGEs) have been well-reported for their anti-cancer effects on various cancers.

AIM OF THE STUDY

The study aimed to examine the effect of AGEs in reversing MDR in colorectal cancer cells.

METHODS

Based on molecular docking and molecular dynamic simulation, the stability of annonacin upon P-gp was investigated. Further in vitro studies were carried in oxaliplatin-resistant human colon cancer cells (SW480R) to study the biological effect of annonacin, in reversing drug resistance in these cells.

RESULTS

Molecular docking and simulation studies have indicated that annonacin stably interacted at the drug binding site of P-gp. In vitro analysis showed that annonacin was able to significantly reduce the expression of P-gp by 2.56 folds. It also induced apoptosis in the drug-resistant colon cancer cells. Moreover, the intracellular accumulation of P-gp substrate (calcein-AM) was observed to increase in resistant cells upon treatment with annonacin.

CONCLUSION

Our findings suggest that annonacin could inhibit the efflux of chemotherapeutic drugs mediated by P-gp and thereby help in reversing MDR in colon cancer cells. Further in vivo studies are required to decipher the underlying mechanism of annonacin in treating MDR cancers.

A comprehensive review on lipid nanocarrier systems for cancer treatment: fabrication, future prospects and clinical trials

Over the last few decades, cancer has been considered a clinical challenge, being among the leading causes of mortality all over the world. Although many treatment approaches have been developed for cancer, chemotherapy is still the most utilized in the clinical setting. However, the available chemotherapeutics-based treatments have several caveats including their lack of specificity, adverse effects as well as cancer relapse and metastasis which mainly explains the low survival rate of patients. Lipid nanoparticles (LNPs) have been utilized as promising nanocarrier systems for chemotherapeutics to overcome the challenges of the currently applied therapeutic strategies for cancer treatment. Loading chemotherapeutic agent(s) into LNPs improves drug delivery at different aspects including specific targeting of tumours, and enhancing the bioavailability of drugs at the tumour site through selective release of their payload, thus reducing their undesired side effects on healthy cells. This review article delineates an overview of the clinical challenges in many cancer treatments as well as depicts the role of LNPs in achieving optimal therapeutic outcomes. Moreover, the review contains a comprehensive description of the many LNPs categories used as nanocarriers in cancer treatment to date, as well as the potential of LNPs for future applications in other areas of medicine and research.

M6A demethylase ALKBH5 regulates FOXO1 mRNA stability and chemoresistance in triple-negative breast cancer

Resistance to chemotherapy is the main reason for treatment failure and poor prognosis in patients with triple-negative breast cancer (TNBC). Although the association of RNA N6-methyladenosine (m6A) modifications with therapy resistance is noticed, its role in the development of therapeutic resistance in TNBC is not well documented. This study aimed to investigate the potential mechanisms underlying reactive oxygen species (ROS) regulation in doxorubicin (DOX)-resistant TNBC. Here, we found that DOX-resistant TNBC cells displayed low ROS levels because of increased expression of superoxide dismutase (SOD2), thus maintaining cancer stem cells (CSCs) characteristics and DOX resistance. FOXO1 is a master regulator that reduces cellular ROS in DOX-resistant TNBC cells, and knockdown of FOXO1 significantly increased ROS levels by inhibiting SOD2 expression. Moreover, the m6A demethylase ALKBH5 promoted m6A demethylation of FOXO1 mRNA and increased FOXO1 mRNA stability in DOX-resistant TNBC cells. The analysis of clinical samples revealed that the increased expression levels of ALKBH5, FOXO1, and SOD2 were significantly positively correlated with chemoresistance and poor prognosis in patients with TNBC. To our knowledge, this is the first study to highlight that ALKBH5-mediated FOXO1 mRNA demethylation contributes to CSCs characteristics and DOX resistance in TNBC cells. Furthermore, pharmacological targeting of FOXO1 profoundly restored the response of DOX-resistant TNBC cells, both in vitro and in vivo. In conclusion, we demonstrated a critical function of ALKBH5-mediated m6A demethylation of FOXO1 mRNA in restoring redox balance, which in turn promoting CSCs characteristics and DOX resistance in TNBC, and suggested that targeting the ALKBH5/FOXO1 axis has therapeutic potential for patients with TNBC refractory to chemotherapy.

Recent strategies for evoking immunogenic Pyroptosis in antitumor immunotherapy

Pyroptosis is a specific type of programmed cell death (PCD) characterized by distinct morphological changes, including cell swelling, membrane blebbing, DNA fragmentation, and eventual cell lysis. Pyroptosis is closely associated with human-related diseases, such as inflammation and malignancies. Since the initial observation of pyroptosis in Shigella flexneri-infected macrophages more than 20 years ago, various pyroptosis-inducing agents, including ions, small molecules, and biological nanomaterials, have been developed for tumor treatment. Given that pyroptosis can activate the body's robust immune response against tumor and promote the formation of the body's long-term immune memory in tumor treatment, its status as a type of immunogenic cell death is self-evident. Therefore, pyroptosis should be used as a powerful anti-tumor strategy. However, there still is a lack of a comprehensive summary of the most recent advances in pyroptosis-based cancer therapy. Therefore, it is vital to fill this gap and inspire future drug design to better induce tumor cells to undergo pyroptosis to achieve advanced anti-tumor effects. In this review, we summarize in detail the most recent advances in triggering tumor cell immunogenic pyroptosis for adequate tumor clearance based on various treatment modalities, and highlight material design and therapeutic advantages. Besides, we also provide an outlook on the prospects of this emerging field in the next development.

Graphene oxide nanosheets conjugated PEG-Glu-Lys-Glu copolymer drug delivery system improves drug-loading rates and enables reduction-sensitive drug release and drug tracking

In this study, the PEG-Glu-Lys-Glu copolymer drug delivery system (GO/PEG-Glu-Lys-Glu) is prepared using glutamate-lysine-glutamate (Glu-Lys-Glu) modified polyethylene glycol (PEG) and connected graphene oxide nanosheets (GO). The multiple carboxyl groups of Glu-Lys-Glu and π-π interactions of GO can increase drug loading rate, and the fluorescence characteristics of GO could monitor the distribution of drug-loading systems in cells and the uptake of cells without the need for external dyes. Paclitaxel (PTX) is loaded via reduction-responsive disulfide bonds as a model medicine to examine the drug delivery potential of GO/PEG-Glu-Lys-Glu. The results showed that the drug loading content of PEG-Glu-Lys-Glu and GO/PEG-Glu-Lys-Glu to PTX is 7.11% and 8.97%, and the loading efficiency is 71.05% and 89.68%, respectively. It's speculated that the π-π interaction between GO and PTX improved the drug-loading capacity and efficiency of GO/PEG-Glu-Lys-Glu. In vitro, in a simulated drug release test, at 48 h, the release of PTX was 85.51% at pH 5.0, 65.12% and 38.32% at pH 6.5 and 7.4, respectively. The cytotoxicity assay results showed that GO/PEG-Glu-Lys-Glu cell inhibition rate to MCF-7 cells was 7.36% at 72 h. The cell inhibition rate of GO/PEG-Glu-Lys-Glu/PTX system at 72 h was 92%, equivalent to free PTX. Therefore, the GO/PEG-Glu-Lys-Glu drug delivery system has the characteristics of good biocompatibility and sustainable release of PTX, which is expected to be applied in the field of tumor therapy.

Multifunctional nanoparticle-mediated combining therapy for human diseases

Combining existing drug therapy is essential in developing new therapeutic agents in disease prevention and treatment. In preclinical investigations, combined effect of certain known drugs has been well established in treating extensive human diseases. Attributed to synergistic effects by targeting various disease pathways and advantages, such as reduced administration dose, decreased toxicity, and alleviated drug resistance, combinatorial treatment is now being pursued by delivering therapeutic agents to combat major clinical illnesses, such as cancer, atherosclerosis, pulmonary hypertension, myocarditis, rheumatoid arthritis, inflammatory bowel disease, metabolic disorders and neurodegenerative diseases. Combinatorial therapy involves combining or co-delivering two or more drugs for treating a specific disease. Nanoparticle (NP)-mediated drug delivery systems, i.e., liposomal NPs, polymeric NPs and nanocrystals, are of great interest in combinatorial therapy for a wide range of disorders due to targeted drug delivery, extended drug release, and higher drug stability to avoid rapid clearance at infected areas. This review summarizes various targets of diseases, preclinical or clinically approved drug combinations and the development of multifunctional NPs for combining therapy and emphasizes combinatorial therapeutic strategies based on drug delivery for treating severe clinical diseases. Ultimately, we discuss the challenging of developing NP-codelivery and translation and provide potential approaches to address the limitations. This review offers a comprehensive overview for recent cutting-edge and challenging in developing NP-mediated combination therapy for human diseases.

Dual impacts of mesenchymal stem cell-derived exosomes on cancer cells: unravelling complex interactions

Mesenchymal stem cells (MSCs) are multipotent, self-renewing stromal cells found in a variety of adult tissues. MSCs possess a remarkable ability to migrate towards tumor sites, known as homing. This homing process is mediated by various factors, including chemokines, growth factors, and extracellular matrix components present in the tumor microenvironment. MSCs release extracellular vesicles known as exosomes (MSC-Exos), which have been suggested to serve a key role in mediating a wide variety of MSC activities. Through cell-cell communication, MSC-Exos have been shown to alter recipient cell phenotype or function and play as a novel cell-free alternative for MSC-based cell therapy. However, MSC recruitment to tumors allows for their interaction with cancer cells and subsequent regulation of tumor behavior. MSC-Exos act as tumor niche modulators via transferring exosomal contents, such as specific proteins or genetic materials, to the nearby cancer cells, leading to either promotion or suppression of tumorigenesis, angiogenesis, and metastasis, depending on the specific microenvironmental cues and recipient cell characteristics. Consequently, there is still a debate about the precise relationship between tumor cells and MSC-Exos, and it is unclear how MSC-Exos impacts tumor cells. Although the dysregulation of miRNAs is caused by the progression of cancer, they also play a direct role in either promoting or inhibiting tumor growth as they act as either oncogenes or tumor suppressors. The utilization of MSC-Exos may prove to be an effective method for restoring miRNA as a means of treating cancer. This review aimed to present the existing understanding of the impact that MSC-Exos could have on cancer. To begin with, we presented a brief explanation of exosomes, MSCs, and MSC-Exos. Following this, we delved into the impact of MSC-Exos on cancer growth, EMT, metastasis, angiogenesis, resistance to chemotherapy and radiotherapy, and modulation of the immune system. Opposing effects of mesenchymal stem cells-derived exosomes on cancer cells.

The mechanisms of multidrug resistance of breast cancer and research progress on related reversal agents

Chemotherapy is the mainstay in the treatment of breast cancer. However, many drugs that are commonly used in clinical practice have a high incidence of side effects and multidrug resistance (MDR), which is mainly caused by overexpression of drug transporters and related enzymes in breast cancer cells. In recent years, researchers have been working hard to find newer and safer drugs to overcome MDR in breast cancer. In this review, we provide the molecule mechanism of MDR in breast cancer, categorize potential lead compounds that inhibit single or multiple drug transporter proteins, as well as related enzymes. Additionally, we have summarized the structure-activity relationship (SAR) based on potential breast cancer MDR modulators with lower side effects. The development of novel approaches to suppress MDR is also addressed. These lead compounds hold great promise for exploring effective chemotherapy agents to overcome MDR, providing opportunities for curing breast cancer in the future.

Co-administration of Chrysin and Luteolin with Cisplatin and Topotecan Exhibits a Variable Therapeutic Value in Human Cancer Cells, HeLa

Combinational treatment is a promising strategy for better cancer treatment outcomes. Chrysin and luteolin have demonstrated effective anticancer activity. Cisplatin and topotecan are commonly used for the treatment of human cancers. However, various side effects including drug resistance are an imperative restriction to use them as pharmacological therapy. Therefore, the aim was to use these agents in combination with flavones for better efficacy. In the present study, it was found that the combination of chrysin and cisplatin and luteolin and cisplatin significantly improved the anticancer effect as both the combinations showed synergistic interactions [combinational index (CI < 1)]. Remarkably, the combination of chrysin and luteolin with topotecan depicted the antagonistic interaction (CI > 1). Further, increased expression of the pro-apoptotic proteins Bax and caspase 8 and the inhibition of the antiapoptotic protein Bcl-2 were instituted in the synergistic doses (chrysin + cisplatin and luteolin + cisplatin), hence promoting apoptosis. Also, it was found that the synergistic combination inhibited the migration of HeLa cells by downregulation of metalloproteases and upregulation of TIMPs. However, there are no significant changes depicted in the antagonistic combinations which support their role in their antagonistic effects. Based on these results, it can be inferred that the two or more drug combinations need to be explored well for their interaction to enhance the therapeutic outcomes.

Fighting Multidrug Resistance with Ruthenium-Cyclopentadienyl Compounds: Unveiling the Mechanism of P-gp Inhibition

The search for more effective and selective drugs to overcome cancer multidrug resistance is urgent. As such, a new series of ruthenium-cyclopentadienyl ("RuCp") compounds with the general formula [Ru(η5-C5H4R)(4,4'-R'-2,2'-bipy)(PPh3)] were prepared and fully characterized. All compounds were evaluated toward non-small cell lung cancer cells with different degrees of cisplatin sensitivity (A549, NCI-H2228, Calu-3, and NCI-H1975), showing better cytotoxicity than the first-line chemotherapeutic drug cisplatin. Compounds 2 and 3 (R' = -OCH3; R = CHO (2) or CH2OH (3)) further inhibited the activity of P-gp and MRP1 efflux pumps by impairing their catalytic activity. Molecular docking calculations identified the R-site P-gp pocket as the preferred one, which was further validated using site-directed mutagenesis experiments in P-gp. Altogether, our results unveil the first direct evidence of the interaction between P-gp and "RuCp" compounds in the modulation of P-gp activity and establish them as valuable candidates to circumvent cancer MDR.

The Application of Nano-drug Delivery System With Sequential Drug Release Strategies in Cancer Therapy

Currently, multidrug combinations are often used clinically to improve the efficacy of oncology chemotherapy, but multidrug combinations often lead to multidrug resistance and decreased performance, resulting in more severe side effects than monotherapy. Therefore, sequential drug release strategies in time and space as well as nano-carriers that respond to the tumor microenvironment have been developed. First, the advantage of the sequential release strategy is that they can load multiple drugs simultaneously to meet their spatiotemporal requirements and stability, thus exerting synergistic effects of two or more drugs. Second, in some cases, sequential drug delivery of different molecular targets can improve the sensitivity of cancer cells to drugs. Control the metabolism of cancer cells, and remodel tumor vasculature. Finally, some drug combinations with built-in release control are used for sequential administration. This paper focuses on the use of nanotechnology and built-in control device to construct drug delivery carriers with different stimulation responses, thus achieving the sequential release of drugs. Therefore, the nano-sequential delivery carrier provides a new idea and platform for the therapeutic effect of various drugs and the synergistic effect among drugs.

Modelling acquired resistance to DOT1L inhibition exhibits the adaptive potential of KMT2A-rearranged acute lymphoblastic leukemia

In KMT2A-rearranged acute lymphoblastic leukemia (ALL), an aggressive malignancy, oncogenic KMT2A-fusion proteins inappropriately recruit DOT1L to promote leukemogenesis, highlighting DOT1L as an attractive therapeutic target. Unfortunately, treatment with the first-in-class DOT1L inhibitor pinometostat eventually leads to non-responsiveness. To understand this we established acquired pinometostat resistance in pediatric KMT2A::AFF1+ B-ALL cells. Interestingly, these cells became mostly independent of DOT1L-mediated H3K79 methylation, but still relied on the physical presence of DOT1L, HOXA9 and the KMT2A::AFF1 fusion. Moreover, these cells selectively lost the epigenetic regulation and expression of various KMT2A-fusion target genes such as PROM1/CD133, while other KMT2A::AFF1 target genes, including HOXA9 and CDK6 remained unaffected. Concomitantly, these pinometostat-resistant cells showed upregulation of several myeloid-associated genes, including CD33 and LILRB4/CD85k. Taken together, this model comprehensively shows the adaptive potential of KMT2A-rearranged ALL cells upon losing dependency on one of its main oncogenic properties.

Repositioning of HMG-CoA Reductase Inhibitors as Adjuvants in the Modulation of Efflux Pump-Mediated Bacterial and Tumor Resistance

Efflux pump (EP)-mediated multidrug resistance (MDR) seems ubiquitous in bacterial infections and neoplastic diseases. The diversity and lack of specificity of these efflux mechanisms raise a great obstacle in developing drugs that modulate efflux pumps. Since developing novel chemotherapeutic drugs requires large investments, drug repurposing offers a new approach that can provide alternatives as adjuvants in treating resistant microbial infections and progressive cancerous diseases. Hydroxy-methyl-glutaryl coenzyme-A (HMG-CoA) reductase inhibitors, also known as statins, are promising agents in this respect. Originally, statins were used in the therapy of dyslipidemia and for the prevention of cardiovascular diseases; however, extensive research has recently been performed to elucidate the functions of statins in bacterial infections and cancers. The mevalonate pathway is essential in the posttranslational modification of proteins related to vital eukaryotic cell functions. In this article, a comparative review is given about the possible role of HMG-CoA reductase inhibitors in managing diseases of bacterial and neoplastic origin. Molecular research and clinical studies have proven the justification of statins in this field. Further well-designed clinical trials are urged to clarify the significance of the contribution of statins to the lower risk of disease progression in bacterial infections and cancerous diseases.

Piperine analog PGP-41 treatment overcomes paclitaxel resistance in NCI/ADR-RES ovarian cells by inhibition of MDR1

Chemoresistance is one of the leading causes of the failure of chemotherapy. Overexpression of P-glycoprotein (P-gp) in cancer cells is one of the most important contributing factors toward the development of chemoresistance. This study was designed to synthesize the derivatives of dihydronaphthyl and to evaluate the P-gp inhibition activity of these compounds. Among all the compounds, PGP-41 showed the most potent P-gp inhibition activity in colorectal adenocarcinoma LS-180 cells. This compound showed potent P-gp inhibition activity in chemoresistant ovarian cell line NCI/ADR-RES. Paclitaxel is one of the first lines of drugs for treating ovarian cancer and is a substrate of P-gp; therefore, NCI/ADR-RES cells are highly resistant to treatment with paclitaxel. Based on this information, we evaluated PGP-41 to overcome the paclitaxel resistance of NCI/ADR-RES cells. PGP-41 was able to sensitize the NCI/ADR-RES cells to the treatment of paclitaxel, which was evident by the reduced IC50 value of paclitaxel from 6.64 μM to 0.12 μM. The sensitization of NCI/ADR-RES cells by PGP-41 was comparable to that of elacridar and Zosuquidar. Further studies revealed that the PGP-41 exerts its effect by downregulating the expression of P-gp. Reduction of P-gp activity leads to the accumulation of higher intracellular concentration of paclitaxel, and thus allowing it to interact with its targets, which further helps in its increased efficacy. Paclitaxel was able to arrest the sensitized NCI/ADR-RES cells into G2M phase, which ultimately led to the induction of apoptotic proteins and the death of cancer cells. Being a different scaffold from zosuquidar and elacridar, further studies are required to develop PGP-41 into a potential drug to overcome chemoresistance in cancer cells.

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.

Inferring density-dependent population dynamics mechanisms through rate disambiguation for logistic birth-death processes

Density dependence is important in the ecology and evolution of microbial and cancer cells. Typically, we can only measure net growth rates, but the underlying density-dependent mechanisms that give rise to the observed dynamics can manifest in birth processes, death processes, or both. Therefore, we utilize the mean and variance of cell number fluctuations to separately identify birth and death rates from time series that follow stochastic birth-death processes with logistic growth. Our nonparametric method provides a novel perspective on stochastic parameter identifiability, which we validate by analyzing the accuracy in terms of the discretization bin size. We apply our method to the scenario where a homogeneous cell population goes through three stages: (1) grows naturally to its carrying capacity, (2) is treated with a drug that reduces its carrying capacity, and (3) overcomes the drug effect to restore its original carrying capacity. In each stage, we disambiguate whether the dynamics occur through the birth process, death process, or some combination of the two, which contributes to understanding drug resistance mechanisms. In the case of limited sample sizes, we provide an alternative method based on maximum likelihood and solve a constrained nonlinear optimization problem to identify the most likely density dependence parameter for a given cell number time series. Our methods can be applied to other biological systems at different scales to disambiguate density-dependent mechanisms underlying the same net growth rate.

Ultrasound-Amplified Enzyodynamic Tumor Therapy by Perovskite Nanoenzyme-Enabled Cell Pyroptosis and Cascade Catalysis

Overcoming apoptosis resistance to achieve efficient breast cancer treatment remains a challenge. The precise induction of another form of programmed cell death, pyroptosis, is an excellent alternative for treating cancer. Ultrasound (US)-enhanced enzyme dynamic (enzyodynamic) therapy is developed by employing LaFeO₃ (LFO) perovskite nanocrystals as a substrate to increase the rate of deleterious reactive oxygen species (ROS) generation for intensive cell pyroptosis. LFO nanocrystals possess quadruple enzyme-mimicking activities, including oxidase-, peroxidase-, glutathione peroxidase-, and catalase-mimicking activities, which undertake the dominant therapeutic task through cascade catalytic reactions, including the reversal of hypoxic microenvironment, depletion of endogenous glutathione, and continuous output of ROS. US exogenous stimulation increases the transition rate of the intermediate complex to Fe (II) and favors incremental ROS production, by which the ROS burst-induced pyroptosis process is accomplished through the ROS-TXNIP-NLRP3-GSDMD pathway. Both in vitro and in vivo antineoplastic outcomes affirm the ascendancy of LFO nanozyme-induced pyroptosis. This work highlights the critical role of US coupled with nanocatalytic reactors in pyroptosis-dominant breast cancer treatment with the apoptosis resistance circumvention feature.

Ruthenium Complex HB324 Induces Apoptosis via Mitochondrial Pathway with an Upregulation of Harakiri and Overcomes Cisplatin Resistance in Neuroblastoma Cells In Vitro

Ruthenium(II) complexes with N-heterocyclic carbene (NHC) ligands have recently attracted attention as novel chemotherapeutic agents. The complex HB324 was intensively studied as an apoptosis-inducing compound in resistant cell lines. HB324 induced apoptosis via mitochondrial pathways. Of particular interest is the upregulation of the Harakiri resistance protein, which inhibits the anti-apoptotic and death repressor proteins Bcl-2 (B-cell lymphoma 2) and BCL-xL (B-cell lymphoma-extra large). Moreover, HB324 showed synergistic activity with various established anticancer drugs and overcame resistance in several cell lines, such as neuroblastoma cells. In conclusion, HB324 showed promising potential as a novel anticancer agent in vitro, suggesting further investigations on this and other preclinical ruthenium drug candidates.

Innovative nanotheranostics: Smart nanoparticles based approach to overcome breast cancer stem cells mediated chemo- and radioresistances

The alarming increase in the number of breast cancer patients worldwide and the increasing death rate indicate that the traditional and current medicines are insufficient to fight against it. The onset of chemo- and radioresistances and cancer stem cell-based recurrence make this problem harder, and this hour needs a novel treatment approach. Competent nanoparticle-based accurate drug delivery and cancer nanotheranostics like photothermal therapy, photodynamic therapy, chemodynamic therapy, and sonodynamic therapy can be the key to solving this problem due to their unique characteristics. These innovative formulations can be a better cargo with fewer side effects than the standard chemotherapy and can eliminate the stability problems associated with cancer immunotherapy. The nanotheranostic systems can kill the tumor cells and the resistant breast cancer stem cells by novel mechanisms like local hyperthermia and reactive oxygen species and prevent tumor recurrence. These theranostic systems can also combine with chemotherapy or immunotherapy approaches. These combining approaches can be the future of anticancer therapy, especially to overcome the breast cancer stem cells mediated chemo- and radioresistances. This review paper discusses several novel theranostic systems and smart nanoparticles, their mechanism of action, and their modifications with time. It explains their relevance and market scope in the current era. This article is categorized under: Therapeutic Approaches and Drug Discovery > Nanomedicine for Oncologic Disease.

Apigenin in cancer therapy: Prevention of genomic instability and anticancer mechanisms

The incidence of cancer has been growing worldwide. Better survival rates following the administration of novel drugs and new combination therapies may concomitantly cause concern regarding the long-term adverse effects of cancer therapy, for example, second primary malignancies. Moreover, overcoming tumour resistance to anticancer agents has been long considered as a critical challenge in cancer research. Some low toxic adjuvants such as herb-derived molecules may be of interest for chemoprevention and overcoming the resistance of malignancies to cancer therapy. Apigenin is a plant-derived molecule with attractive properties for chemoprevention, for instance, promising anti-tumour effects, which may make it a desirable adjuvant to reduce genomic instability and the risks of second malignancies among normal tissues. Moreover, it may improve the efficiency of anticancer modalities. This paper aims to review various effects of apigenin in both normal tissues and malignancies. In addition, we explain how apigenin may have the ability to protect usual cells against the genotoxic repercussions following radiotherapy and chemotherapy. Furthermore, the inhibitory effects of apigenin on tumours will be discussed.

Nanoparticles design considerations to co-deliver nucleic acids and anti-cancer drugs for chemoresistance reversal

Chemoresistance and hence the consequent treatment failure is considerably challenging in clinical cancer therapeutics. The understanding of the genetic variations in chemoresistance acquisition encouraged the use of gene modulatory approaches to restore anti-cancer drug efficacy. Many smart nanoparticles are designed and optimized to mediate combinational therapy between nucleic acid and anti-cancer drugs. This review aims to define a rational design of such co-loaded nanocarriers with the aim of chemoresistance reversal at various cellular levels to improve the therapeutic outcome of anticancer treatment. Going through the principles of therapeutics loading, physicochemical characteristics tuning, and different nanocarrier modifications, also looking at combination effectiveness on chemosensitivity restoration. Up to now, these emerging nanocarriers are in development status but are expected to introduce outstanding outcomes.

Molecular design, synthesis and biological evaluation of novel 1,2,5-trisubstituted benzimidazole derivatives as cytotoxic agents endowed with ABCB1 inhibitory action to overcome multidrug resistance in cancer cells

Multidrug resistance (MDR) is a leading cause for treatment failure in cancer patients. One of the reasons of MDR is drug efflux by ATP-binding cassette (ABC) transporters in eukaryotic cells especially ABCB1 (P-glycoprotein). In this study, certain novel 1,2,5-trisubstituted benzimidazole derivatives were designed utilising ligand based pharmacophore approach. The designed benzimidazoles were synthesised and evaluated for their cytotoxic activity towards doxorubicin-sensitive cell lines (CCRF/CEM and MCF7), as well as against doxorubicin-resistant cancer cells (CEM/ADR 5000 and Caco-2). In particular, compound VIII showed a substantial cytotoxic effect in all previously mentioned cell lines especially in doxorubicin-resistant CEM/ADR5000 cells (IC₅₀ = 8.13 µM). Furthermore, the most promising derivatives VII, VIII and XI were tested for their ABCB1 inhibitory action in the doxorubicin-resistant CEM/ADR 5000 subline which is known for overexpression of ABCB1 transporters. The results showed that compound VII exhibited the best ABCB1 inhibitory activity at three tested concentrations (22.02 µM (IC₅₀), 50 µM and 100 µM) in comparison to verapamil as a reference ABCB1 inhibitor. Such inhibition resulted in a synergistic effect and a massive decrease in the IC₅₀ of doxorubicin (34.5 µM) when compound VII was used in a non-toxic dose in combination with doxorubicin in doxorubicin-resistant cells CEM/ADR 5000 (IC_50(Dox+VII) = 3.81 µM). Molecular modelling studies were also carried out to explain the key interactions of the target benzimidazoles at the ABCB1 binding site. Overall the obtained results from this study suggest that 1,2,5-trisubstituted benzimidazoles possibly are promising candidates for further optimisation and development of potential anticancer agents with ABCB1 inhibitory activity and therefore overcome MDR in cancer cells.

Conquering Cancer Multi-Drug Resistance Using Curcumin and Cisplatin Prodrug-Encapsulated Mesoporous Silica Nanoparticles for Synergistic Chemo- and Photodynamic Therapies

Recently, the development of anti-cancer approaches using different physical or chemical pathways has shifted from monotherapy to synergistic therapy, which can enhance therapeutic effects. As a result, enormous efforts have been devoted to developing various delivery systems encapsulated with dual agents for synergistic effects and to combat cancer cells acquired drug resistance. In this study, we show how to make Institute of Bioengineering and Nanotechnology (IBN)-1-based mesoporous silica nanoparticles (MSNs) for multifunctional drug delivery to overcome drug resistance cancer therapy. Initially, curcumin (Cur)-embedded IBN-1 nanocomposites (IBN-1-Cur) are synthesized in a simple one-pot co-condensation and then immobilized with the prodrug of Cisplatin (CP) on the carboxylate-modified surface (IBN-1-Cur-CP) to achieve photodynamic therapy (PDT) and chemotherapy in one platform, respectively, in the fight against multidrug resistance (MDR) of MES-SA/DX5 cancer cells. The Pluronic F127 triblock copolymer, as the structure-directing agent, in nanoparticles acts as a p-glycoprotein (p-gp) inhibitor. These designed hybrid nanocomposites with excellent structural properties are efficiently internalized by the endocytosis and successfully deliver Cur and CP molecules into the cytosol. Furthermore, the presence of Cur photosensitizer in the nanochannels of MSNs resulted in increased levels of cellular reactive oxygen species (ROS) under light irradiation. Thus, IBN-1-Cur-CP showed excellent anti-cancer therapy in the face of MES-SA/DX5 resistance cancer cells, owing to the synergistic effects of chemo- and photodynamic treatment.

Mesenchymal stem cell-derived exosomes in cancer therapy resistance: recent advances and therapeutic potential

Mesenchymal stem cells (MSCs) are multipotent stromal cells that can be obtained from various human tissues and organs. They can differentiate into a wide range of cell types, including osteoblasts, adipocytes and chondrocytes, thus exhibiting great potential in regenerative medicine. Numerous studies have indicated that MSCs play critical roles in cancer biology. The crosstalk between tumour cells and MSCs has been found to regulate many tumour behaviours, such as proliferation, metastasis and epithelial-mesenchymal transition (EMT). Multiple lines of evidence have demonstrated that MSCs can secrete exosomes that can modulate the tumour microenvironment and play important roles in tumour development. Notably, very recent works have shown that mesenchymal stem cell-derived exosomes (MSC-derived exosomes) are critically involved in cancer resistance to chemotherapy agents, targeted-therapy drugs, radiotherapy and immunotherapy. In this review, we systematically summarized the emerging roles and detailed molecular mechanisms of MSC-derived exosomes in mediating cancer therapy resistance, thus providing novel insights into the clinical applications of MSC-derived exosomes in cancer management.

Extracellular Vesicles and Circulating Tumour Cells - complementary liquid biopsies or standalone concepts?

Liquid biopsies do promise a lot, but are they keeping it? In the past decade, additional novel biomarkers qualified to be called like that, of which, some took necessary hurdles resulting in FDA approval and clinical use. Some others are since a while around, well known and were once regarded to be a game changer in cancer diagnosis or cancer screening. But, during their clinical use limitations were observed from statistical significance and questions raised regarding their robustness, that eventually led to be dropped from associated clinical guidelines for certain applications including cancer diagnosis. The purpose of this review isn't to give a broad overview of all current liquid biopsy as biomarkers, weight them and promise a brighter future in cancer prevention, but rather to take a deeper look on two of those who do qualify to be called liquid biopsies now or then. These two are probably of greatest interest conceptually and methodically, and likely have the highest chances to be in clinical use soon, with a portfolio extension over their original conceptual usage. We aim to dig deeper beyond cancer diagnosis or cancer screening. Actually, we aim to review in depth extracellular vesicles (EVs) and compare with circulating tumour cells (CTCs). The latter methodology is partially FDA approved and in clinical use. We will lay out similarities as taking advantage of surface antigens on EVs and CTCs in case of characterization and quantification. But drawing readers' attention to downstream application based on capture/isolation methodology and simply on their overall nature, here apparently being living material eventually recoverable as CTCs are vs. dead material with transient effects on recipient cell as in case of EVs. All this we try to bring in perspective, compare and conclude towards which future direction we are aiming for, or should aim for. Do we announce a winner between CTCs vs EVs? No, but we provide good reasons to intensify research on them.

Overview of non-coding RNAs in breast cancers

Breast cancer in women is the second most common cancer and the fifth leading cause of cancer death worldwide. Although earlier diagnosis and detection of breast cancer has resulted in lower mortality rates, further advances in prevention, detection, and treatment are needed to improve outcomes and survival for women with breast cancer as well as to offer a personalized therapeutic approach. It is now well-established that non-coding RNAs (ncRNAs) represent 98% of the transcriptome but in-depth knowledge about their involvement in the regulation of gene expression is lacking. A growing body of research indicates that ncRNAs are essential for tumorigenesis by regulating the expression of tumour-related genes. In this review, we focus on their implication in breast cancer genesis but also report the latest knowledge of their theragnostic and therapeutic role. We highlight the need for accurate quantification of circulating ncRNAs which is determinant to develop reliable biomarkers. Further studies are mandatory to finally enter the era of personalized medicine for women with breast cancer.

Lung Cancer Targeted Chemoradiotherapy via Dual-Stimuli Responsive Biodegradable Core-Shell Nanoparticles

Lung cancer is one of the major causes of cancer-related deaths worldwide, primarily because of the limitations of conventional clinical therapies such as chemotherapy and radiation therapy. Side effects associated with these treatments have made it essential for new modalities, such as tumor targeting nanoparticles that can provide cancer specific therapies. In this research, we have developed novel dual-stimuli nanoparticles (E-DSNPs), comprised of two parts; (1) Core: responsive to glutathione as stimuli and encapsulating Cisplatin (a chemo-drug), and (2) Shell: responsive to irradiation as stimuli and containing NU7441 (a radiation sensitizer). The targeting moieties on these nanoparticles are Ephrin transmembrane receptors A2 (EphA2) that are highly expressed on the surfaces of lung cancer cells. These nanoparticles were then evaluated for their enhanced targeting and therapeutic efficiency against lung cancer cell lines. E-DSNPs displayed very high uptake by lung cancer cells compared to healthy lung epithelial cells. These nanoparticles also demonstrated a triggered release of both drugs against respective stimuli and a subsequent reduction in in vitro cancer cell survival fraction compared to free drugs of equivalent concentration (survival fraction of about 0.019 and 0.19, respectively). Thus, these nanoparticles could potentially pave the path to targeted cancer therapy, while overcoming the side effects of conventional clinical therapies.

Photocatalytic Superoxide Radical Generator that Induces Pyroptosis in Cancer Cells

Pyroptosis, a newly characterized form of immunogenic cell death, is attracting increasing attention as a promising approach to cancer immunotherapy. However, biocompatible strategies to activate pyroptosis remain rare. Here, we show that a photocatalytic superoxide radical (O₂^-•) generator, NI-TA, triggers pyroptosis in cancer cells. NI-TA was designed to take advantage of an intramolecular triplet-ground state splitting energy modulation approach. Detailed studies revealed that the pyroptosis triggered by NI-TA under conditions of photoexcitation proceeds through a caspase-3/gasdermin E (GSDME) pathway rather than via canonical processes involving caspase-1/gasdermin-D (GSDMD). NI-TA was found to function via a partial-O₂-recycling mode of action and to trigger cell pyroptosis and provide for effective cancer cell ablation even under conditions of hypoxia (≤2% O₂). In the case of T47D 3D multicellular spheroids, good antitumor efficiency and stemness inhibition are achieved. This work highlights how photocatalytic chemistry may be leveraged to develop effective pyroptosis-inducing agents.

The dual interaction of antimicrobial peptides on bacteria and cancer cells; mechanism of action and therapeutic strategies of nanostructures

Microbial infection and cancer are two leading causes of global mortality. Discovering and developing new therapeutics with better specificity having minimal side-effects and no drug resistance are of an immense need. In this regard, cationic antimicrobial peptides (AMP) with dual antimicrobial and anticancer activities are the ultimate choice. For better efficacy and improved stability, the AMPs available for treatment still required to be modified. There are several strategies in which AMPs can be enhanced through, for instance, nano-carrier application with high selectivity and specificity enables researchers to estimate the rate of drug delivery to a particular tissue. In this review we present the biology and modes of action of AMPs for both anticancer and antimicrobial activities as well as some modification strategies to improve the efficacy and selectivity of these AMPs.

Chemodynamic and Photothermal Combination Therapy Based on Dual-Modified Metal-Organic Framework for Inducing Tumor Ferroptosis/Pyroptosis

Single therapy for tumor therapy always exerts limited ability for the constraints on the reaction condition and the unavoidable multidrug resistance, which seriously influences the therapy effect in the clinic. Herein, a combination treatment nanosystem (MP@PI) based on chemodynamic therapy (CDT) and photothermal therapy (PTT) is constructed for triggering ferroptosis/pyroptosis, which is the metal-organic framework (MOF) modified with polydopamine (PDA) and IR820 to loaded with piperlongumine (PL). The MOF and PL respectively served as the iron source and H₂O₂ source, performing chemodynamic therapy (CDT) for eliciting ferroptosis. Meanwhile the iron source induces pyroptosis in tumor cells. PDA is not only pH responsive to release PL but also CDT-assisted which due to PDA consumes the glutathione to decrease the expression of glutathione peroxide 4. The photosensitizer IR820 exerts photothermal effects under near-infrared light and further facilitates the ferroptosis/pyroptosis. In addation, the MP@PI nanoplatform evokes the immune response in vivo and enhances the antitumor effects further. Overall, MP@PI is a kind of promising cancer therapy strategy through CDT and PTT combination, inducing ferroptosis and pyroptosis.

Structural insight into SSE15206 in complex with tubulin provides a rational design for pyrazolinethioamides as tubulin polymerization inhibitors

Background: Tubulin protein is a promising target for antitumor drugs. Some tubulin inhibitors targeting the colchicine binding site are not substrates of the multidrug-resistance efflux pump, which can overcome the mechanism of drug resistance mediated by P-glycoprotein. Methodology/results: SSE15206 is a colchicine binding site inhibitor with antiproliferative activity against different drug-resistant cell lines. Unfortunately, the lack of detailed interaction information about SSE15206 in complex with tubulin impeded the development of potent drugs that possess similar scaffolds. Herein, the authors report the crystal structure of the tubulin-SSE15206 complex at a resolution of 2.8 Å. Conclusion: The complex structure reveals the intermolecular interactions between SSE15206 and tubulin, providing a rationale for the development of pyrazolinethioamides as tubulin polymerization inhibitors and to overcome multidrug resistance.

MicroRNAs and drug resistance in colorectal cancer with special focus on 5-fluorouracil

Colorectal cancer is globally one of the most common cancers in all age groups. The current chemotherapy combinations for colorectal cancer treatment include 5-fluorouracil-based regimens; however, drug resistance remains one of the main reasons for chemotherapy failure and disease recurrence. Many studies have determined colorectal cancer chemoresistance mechanisms such as drug efflux, cell cycle arrest, DNA damage repair, apoptosis, autophagy, vital enzymes, epigenetic, epithelial-mesenchymal transition, stem cells, and immune system suppression. Several microRNAs affect drug resistance by regulating the drug resistance-related target genes in colorectal cancer. These drug resistance-related miRNAs may be used as promising biomarkers for predicting drug response or as potential therapeutic targets for treating patients with colorectal cancer. This work reviews and discuss the role of selected microRNAs in 5-fluorouracil resistance and their molecular mechanisms in colorectal cancer.

Research Progress and Prospects of Autophagy in the Mechanism of Multidrug Resistance in Tumors

Although the treatment of cancer has made great strides in clinical practice, its high morbidity and fatality rates remain a major threat to human health. Multidrug resistance (MDR) often appears in the process of tumor treatment, leading to tumor refractory and aggravating the risk of tumor recurrence. Therefore, antitumor MDR plays a key role in tumor chemotherapy. Autophagy is an important process for the turnover of intracellular materials, which is commonly seen in the treatment of sensitive and multidrug-resistant tumors, and it can play different roles in various types of MDR tumor cells and tissues. Autophagy plays a dual regulatory role in MDR tumors. On the one hand, autophagy can promote the formation of MDR in tumor cells, weaken the killing effect of chemotherapy drugs on tumor cells, and play a protective role in tumor survival. On the other hand, autophagy production in the cellular environment can kill MDR tumor cells, reverse tumor resistance and enhance the efficiency of chemotherapy drugs. Therefore, the regulation of autophagy to overcome MDR has become increasingly significant in tumor chemotherapy. In this article, we discussed and summarized the research progress of autophagy in MDR tumors, mainly involving the different characteristics of autophagy in MDR cancer cells.

The Emerging Roles of Circular RNAs in the Chemoresistance of Gastrointestinal Cancer

Gastrointestinal (GI) cancer represents a major global health problem due to its aggressive characteristics and poor prognosis. Despite the progress achieved in the development of treatment regimens, the clinical outcomes and therapeutic responses of patients with GI cancer remain unsatisfactory. Chemoresistance arising throughout the clinical intervention is undoubtedly a critical barrier for the successful treatment of GI cancer. However, the precise mechanisms associated with chemoresistance in GI cancer remain unclear. In the past decade, accumulating evidence has indicated that circular RNAs (circRNAs) play a key role in regulating cancer progression and chemoresistance. Notably, circRNAs function as molecular sponges that sequester microRNAs (miRNAs) and/or proteins, and thus indirectly control the expression of specific genes, which eventually promote or suppress drug resistance in GI cancer. Therefore, circRNAs may represent potential therapeutic targets for overcoming drug resistance in patients with GI cancer. This review comprehensively summarizes the regulatory roles of circRNAs in the development of chemoresistance in different GI cancers, including colorectal cancer, gastric cancer and esophageal cancer, as well as deciphers the underlying mechanisms and key molecules involved. Increasing knowledge of the important functions of circRNAs underlying drug resistance will provide new opportunities for developing efficacious therapeutic strategies against GI cancer.

Systemic Mobilization of Breast Cancer Resistance Protein in Response to Oncogenic Stress

Simple Summary

The drug efflux mediated by xenobiotic transporters is one of the best recognized mechanisms of multidrug resistance in cancer that leads to the failure of therapeutic approaches. The aim of our research was to examine the influence of a growing tumor on the activity of xenobiotic transport in the host. Our study reveals a strong correlation between the development of melanoma tumor in mice and the level of breast cancer resistance protein, one of the major xenobiotic transporters, and its transcript in the normal tissues of the hosts distant from the tumor site. The systemic effects of the tumor are confirmed by a drastically enhanced xenobiotic transport, which is correlated with changes in the level of cytokines in blood. Such an unexpected type of tumor–host interaction, which leads to the systemic upregulation of breast cancer resistance protein, and very likely of other xenobiotic transporters too, has broad implications for cancer therapies, including chemotherapy and photodynamic therapy. Our findings shed new light on the biology of cancer and the complexity of cancer–host interactions that should be taken into account in the design of new generations of anti-cancer drugs and personalized medicine.

Abstract

The breast cancer resistance protein (BCRP or ABCG2) involved in cancer multidrug resistance (MDR), transports many hydrophobic compounds, including a number of anti-cancer drugs. Our comprehensive study using a mouse model reveals that a subcutaneously growing tumor strongly affects the expression of BCRP in the host’s normal organs on both the transcriptional and translational level. Additionally, the efflux of BCRP substrates is markedly enhanced. The levels of BCRP and its transcript in normal tissues distant from the tumor site correlate with tumor growth and the levels of cytokines in the peripheral blood. Thus, oncogenic stress causes transient systemic upregulation of BCRP in the host’s normal tissues and organs, which is possibly mediated via cytokines. Because BCRP upregulation takes place in many organs as early as the initial stages of tumor development, it reveals a most basic mechanism that may be responsible for the induction of primary MDR. We hypothesize that such effects are not tumor-specific responses, but rather constitute a more universal defense strategy. The xenobiotic transporters are systemically mobilized due to various stresses, seemingly in a pre-emptive manner so that the body can be quickly and efficiently detoxified. Our findings shed new light on the biology of cancer and on the complexity of cancer–host interactions and are highly relevant to cancer therapies as well as to the design of new generations of therapeutics and personalized medicine.

Cancer drug resistance related microRNAs: recent advances in detection methods

MiRNAs are related to cancer drug resistance through various mechanisms. The advanced detection methods for the miRNAs are reviewed.

Intracellular Condensates of Oligopeptide for Targeting Lysosome and Addressing Multiple Drug Resistance of Cancer

Biomolecular condensates have been demonstrated as a ubiquitous phenomenon in biological systems and play a crucial role in controlling cellular functions. However, the spatiotemporal construction of artificial biomolecular condensates with functions remains challenging and has been less explored. Herein, a general approach is reported to construct biomolecular condensates (e.g., hydrogel) in the lysosome of living cells for cancer therapy and address multiple drug resistance induced by lysosome sequestration. Aromatic-motif-appended pH-responsive hexapeptide (LTP) derived from natural insulin can be uptaken by cancer cells mainly through caveolae-dependent endocytosis, ensuring the proton-triggered phase transformation (solution to hydrogel) of LTP inside the lysosome specifically. Lysosomal hydrogelation further leads to enlargement of the lysosome in cancer cells and increases the permeability of the lysosome, resulting in cancer cell death. Importantly, lysosomal assemblies can significantly improve the efficiency of current chemotherapy drugs toward multidrug resistance (MDR) cells in vitro and in xenograft tumor models. As an example of functional artificial condensates in lysosomes, this work provides a new strategy for controlling functional condensates formation precisely in the organelles of living cells and addressing MDR in cancer therapy.

Cellular Self-Digestion and Persistence in Bacteria

Cellular self-digestion is an evolutionarily conserved process occurring in prokaryotic cells that enables survival under stressful conditions by recycling essential energy molecules. Self-digestion, which is triggered by extracellular stress conditions, such as nutrient depletion and overpopulation, induces degradation of intracellular components. This self-inflicted damage renders the bacterium less fit to produce building blocks and resume growth upon exposure to fresh nutrients. However, self-digestion may also provide temporary protection from antibiotics until the self-digestion-mediated damage is repaired. In fact, many persistence mechanisms identified to date may be directly or indirectly related to self-digestion, as these processes are also mediated by many degradative enzymes, including proteases and ribonucleases (RNases). In this review article, we will discuss the potential roles of self-digestion in bacterial persistence.

Discovery of a Series of Hydroxamic Acid-Based Microtubule Destabilizing Agents with Potent Antitumor Activity

Hydroxamic acid group is one of the characteristic pharmacophores of histone deacetylase (HDAC) inhibitors. But here, we discovered a series of hydroxamic acid-based microtubule destabilizing agents (MDAs), which were derived from shortening the length of the linker in HDAC6 inhibitor SKLB-23bb. Interestingly, the low nanomolar antiproliferative activity of these MDAs depended on the presence of hydroxamic acid groups, but their inhibitory effects on HDAC were lost. Among them, 12b showed favorable metabolism stability, high bioavailability, and potent antitumor activity in multidrug-resistant cell lines and A2780/T xenograft model. More importantly, in the patient-derived xenograft models of triple-negative breast cancer and osimertinib-resistant non-small-cell lung cancer, both 20 mg/kg oral and 10 mg/kg intravenous administration of 12b could induce more than 70% tumor inhibition without obvious toxicity. Overall, we discovered that 12b, as a novel MDA based on hydroxamic acid, could serve as a potential MDA for further investigation.

Effects of Combinatorial Ubiquitinated Protein-Based Nanovaccine and STING Agonist in Mice With Drug-Resistant and Metastatic Breast Cancer

We previously reported that enriched ubiquitinated proteins (UPs) from tumor cells have the potential to be used as immunotherapy vaccine against cancer. Here we enriched UPs from epirubicin (EPB)-induced multi-drug-resistant cancer stem-like breast cancer cell line (4T1/EPB) and tested the efficacy of α-Al₂O₃-UPs-4T1/EPB (short for UPs-4T1/EPB) as therapeutic vaccine alone and in combination with the stimulator of interferon genes (STING) agonist in mice with drug-resistant and metastatic breast cancer. Vaccination with UPs-4T1/EPB exerted profound anti-tumor effects through augmented specific CD8⁺ T cell responses and amplified T cell receptor diversity of tumor-infiltrating lymphocytes (TILs). Importantly, the combination with STING agonist further facilitated the migration of mature CD8α⁺ dendritic cells to the lymph nodes and the infiltration of TILs within tumors, resulting in primary tumor regression and pulmonary metastasis eradication in mice. Moreover, the cured mice were completely resistant against a subsequent rechallenge with the same tumor. Our study indicates that this novel combinatorial immunotherapy with UPs-4T1/EPB vaccine and STING agonist is effective in mice with drug-resistant and metastatic breast cancer.

Pro-Oncogenic c-Met/EGFR, Biomarker Signatures of the Tumor Microenvironment are Clinical and Therapy Response Prognosticators in Colorectal Cancer, and Therapeutic Targets of 3-Phenyl-2H-benzo[e][1,3]-Oxazine-2,4(3H)-Dione Derivatives

Genetic and environmental factors play important roles in cancer progression, metastasis, and drug resistance. Herein, we used a multiomics data analysis to evaluate the predictive and prognostic roles of genetic and epigenetic modulation of c-MET (hepatocyte growth factor receptor)/epidermal growth factor receptor (EGFR) in colorectal cancer (CRC). First, we found that overexpressions of c-MET/EGFR were associated with the infiltration of tumor immune cells and cancer-associated fibroblasts, and were of prognostic relevance in CRC cohorts. We also observed that genetic alterations of c-MET/EGFR in CRC co-occurred with other gene alterations and were associated with overexpression of messenger (m)RNA of some cancer hallmark proteins. More specifically, DNA-methylation and somatic copy number alterations of c-MET/EGFR were associated with immune infiltration, dysfunctional T-cell phenotypes, and poor prognoses of the cohorts. Moreover, we describe two novel gefitinib-inspired small molecules derivatives of 3-phenyl-2H-benzo[e] [1,3]-oxazine-2,4(3H)-dione, NSC777205 and NSC777207, which exhibited wide-spectrum antiproliferative activities and selective cytotoxic preference for drug-sensitive and multidrug-resistant melanoma, renal, central nervous system, colon, and non-small cell lung cancer cell lines. We further provided in silico mechanistic evidence implicating c-MET/EGFR/phosphatidylinositol 3-kinase (PI3K)-mammalian target of rapamycin (mTOR) inhibition in anticancer activities of those compounds. Our overall structure-activity relationship study revealed that the addition of an –OCH₃ group to salicylic core of NSC777207 was not favorable, as the added moiety led to overall less-favorable drug properties as well as weaker anticancer activities compared to the properties and activities demonstrated by NSC777205 that has no –OCH₃ substituent group. Further in vitro and in vivo analyses in tumor-bearing mice are ongoing in our lab to support this claim and to unravel the full therapeutic efficacies of NSC777205 and NSC777207 in CRC.

Genomic and epigenomic evolution of acquired resistance to combination therapy in esophageal squamous cell carcinoma

BACKGROUNDTargeted arterial infusion of verapamil combined with chemotherapy (TVCC) is an effective clinical interventional therapy for esophageal squamous cell carcinoma (ESCC), but multidrug resistance (MDR) remains the major cause of relapse or poor prognosis, and the underlying molecular mechanisms of MDR, temporal intratumoral heterogeneity, and clonal evolutionary processes of resistance have not been determined.METHODSTo elucidate the roles of genetic and epigenetic alterations in the evolution of acquired resistance during therapies, we performed whole-exome sequencing on 16 serial specimens from 7 patients with ESCC at every cycle of therapeutic intervention from 3 groups, complete response, partial response, and progressive disease, and we performed whole-genome bisulfite sequencing for 3 of these 7 patients, 1 patient from each group.RESULTSPatients with progressive disease exhibited a substantially higher genomic and epigenomic temporal heterogeneity. Subclonal expansions driven by the beneficial new mutations were observed during combined therapies, which explained the emergence of MDR. Notably, SLC7A8 was identified as a potentially novel MDR gene, and functional assays demonstrated that mutant SLC7A8 promoted the resistance phenotypes of ESCC cell lines. Promoter methylation dynamics during treatments revealed 8 drug resistance protein-coding genes characterized by hypomethylation in promoter regions. Intriguingly, promoter hypomethylation of SLC8A3 and mutant SLC7A8 were enriched in an identical pathway, protein digestion and absorption, indicating a potentially novel MDR mechanism during treatments.CONCLUSIONOur integrated multiomics investigations revealed the dynamics of temporal genetic and epigenetic inter- and intratumoral heterogeneity, clonal evolutionary processes, and epigenomic changes, providing potential MDR therapeutic targets in treatment-resistant patients with ESCC during combined therapies.FUNDINGNational Natural Science Foundation of China, Science Foundation of Peking University Cancer Hospital, CAMS Innovation Fund for Medical Sciences, Major Program of Shenzhen Bay Laboratory, Guangdong Basic and Applied Basic Research Foundation, and the third round of public welfare development and reform pilot projects of Beijing Municipal Medical Research Institutes.