Progress in the studies on the molecular mechanisms associated with multidrug resistance in cancers

Design, synthesis, and biological evaluation of C-12 modified ocotillol-type derivatives as novel P-glycoprotein modulators for overcoming multidrug resistance

Ocotillol-type ginsenoside derivatives exhibit significant potential as modulators of P-glycoprotein (Pgp). To date, structural investigations of Ocotillol-type saponins have predominantly focused on modifications at the C-3 position of the A-ring, with limited exploration of the C-12 position on the C-ring. In this study, we designed and synthesized a series of C-12 modified ocotillol-type derivatives and assessed their efficacy in reversing multidrug resistance (MDR) in KBV cells. Most of the newly synthesized derivatives exhibited minimal cytotoxicity and potent MDR reversal capabilities. Notably, compound 9e emerged as the most effective agent in reversing tumor MDR in vitro, showing more than twice the potency of verapamil. Furthermore, 9e displayed high selectivity for Pgp, being 40- and 20-fold more effective than verapamil in inhibiting Rh123 efflux and enhancing doxorubicin sensitivity, respectively. Molecular docking analysis revealed that 9e possesses a unique T-shaped configuration that occupies the access channel of Pgp, obstructing the peristaltic extrusion mechanism of TM12 and TM9, thereby inhibiting the efflux function of Pgp. Overall, 9e represents a promising lead compound for the development of novel Pgp modulators to overcome MDR in cancer therapy.

Serum-derived extracellular vesicles mediate acquired multidrug resistance of MCF-7 breast cancer cells induced by chemotherapeutic drugs

Multidrug resistance (MDR) in tumor cells presents a significant challenge in cancer therapy. This study investigates the role of serum-derived extracellular vesicles (EVs) in mediating MDR during chemotherapeutic exposure. The findings indicate that short- or long-term co-incubation of doxorubicin (Dox)-pretreated serum derived EVs (EVs(S-PT)) caused drug-sensitive MCF-7 breast cancer cells to develop a MDR phenotype. In addition, serum EVs contain a high concentration of unglycosylated P-glycoprotein (P-gp). Chemotherapy treatment of tumor patients or exposure to chemotherapeutic drugs in vitro activates serum glycosyltransferases, inducing glycosylation of EVs P-gp and giving it drug-pumping activity. Furthermore, damage caused by Dox to the vascular endothelial barrier facilitates the crossing of serum EVs into the tumor microenvironment. These EVs are then taken up by tumor cells, providing them with access to a significant quantity of glycosylated P-gp proteins that possess transporter activity and the ability to evade degradation by the ubiquitin proteasome system. The results indicate that EVs(S-PT) transfers glycosylated P-gp across the damaged vascular endothelial barrier into MCF-7 cells and that these glycosylated P-gp remain intracellular for a long period of time, inducing MDR in the cells. Our study highlights a novel mechanism of acquired MDR and provides a potential avenue for therapeutic interventions targeting the serum EVs pathway in cancer therapy.

Portrayal of the complex molecular landscape of multidrug resistance in gastric cancer: Unveiling the potential targets

Gastric cancer (GC) is an aggressive malignancy among all Gastrointestinal cancer (GIC) types. Worldwide, among all cancer types, gastric cancer incidence and related mortality remain in fifth position. Multidrug resistance (MDR) in GC presents a major challenge to chemotherapy, and it significantly affects patient survival. A better understanding of the dynamic interaction of cellular factors contributing to MDR phenotype, e.g., the presence and expression of variants of MDR-related genes, including various drug-detoxifying and drug-efflux transporters, and expression of regulatory ncRNAs affecting the expression of MDR-related genes, is required to comprehend the molecular mechanisms for MDR development in GCs. This review article provides a holistic discussion of the cellular factors involved in the MDR development in GC cells, i.e., their roles and cross-talk between specific molecules that give rise to drug-sensitive and drug-resistant phenotypes. Moreover, the pharmacological perspective of drug resistance and the underlying biological processes that allow the escape of GC cells from the cytotoxic effects of drugs have also been discussed. Additionally, this review article provides an in-depth discussion on most potential candidates that can serve as MDR biomarkers in GIC cancer and the growing research interest in non-coding RNAs (ncRNAs) in GC. Notably, the miRNAs, circRNAs, and lncRNAs are not only emerging as crucial prognostic biomarkers of MDR in gastric cancers but also as potential targets for personalized medicine to combat the MDR challenge in GC patients.

ML210 Antagonizes ABCB1- Not ABCG2-Mediated Multidrug Resistance in Colorectal Cancer

Objectives: ABCB1-mediated multidrug resistance (MDR) compromises chemotherapy efficacy in colorectal cancer (CRC). Despite decades of research, no selective ABCB1 inhibitor has achieved clinical success. This study investigates ML210 as a novel ABCB1-specific inhibitor to reverse ABCB1-driven MDR. Methods: Cytotoxicity assays (MTT) were performed on ABCB1-overexpressing HCT-8/V and ABCG2-overexpressing S1-M1-80 CRC cells. Drug accumulation (doxorubicin/mitoxantrone) was quantified via flow cytometry, and cell cycle effects were analyzed using propidium iodide staining. Molecular docking utilized the ABCB1 crystal structure. Results: ML210 selectively reversed ABCB1-mediated resistance to doxorubicin and vincristine in HCT-8/V cells, enhancing intracellular drug accumulation without affecting ABCG2 activity. It induced cell cycle arrest in ABCB1-overexpressing cells and did not alter ABCB1 protein expression. Molecular docking revealed stable binding of ML210 within the ABCB1 substrate pocket through hydrophobic interactions and hydrogen bonding. Conclusions: ML210 is a selective ABCB1 inhibitor that circumvents MDR via direct transport blockade, offering a targeted strategy against ABCB1-mediated chemoresistance in CRC. Its specificity for ABCB1 over ABCG2 highlights potential clinical advantages.

An insight into the in vivo antitumor therapeutic potential of indole-(fused) pyri(mi)dine hybrids

Cancer can invade and destroy any part of the body, representing a grand social, public health, and economic challenge. Chemotherapy plays a crucial role in cancer treatment, and in recent decades, hundreds of anticancer chemotherapeutics have been introduced. Nevertheless, multidrug resistance and side effects are the main obstacles to successful cancer therapy, highlighting the pressing requirement for the development of new chemotherapeutics to address the above issues. Indole hybrids not only have the potential to surmount drug resistance and adverse effects caused by individual components but also can enhance efficacy and improve pharmacokinetic characteristics since hybrid molecules can concurrently regulate multiple targets within cancer cells. Moreover, numerous indole hybrids exemplified by mobocertinib (indole-pyrimidine hybrid) and osimertinib (indole-quinazoline hybrid) have already been utilized in clinical cancer treatment. Therefore, indole hybrids have emerged as valuable scaffolds for the treatment and eradication of cancer. This review aims to elucidate the current landscape of indole-(fused) pyri(mi)dine hybrids, including indole-quinolines/quinolinones, indole-pyridines, indole-pyrimidines, and indole-fused pyrimidines, with in vivo antitumor therapeutic potential, offering effective candidates for in-depth preclinical evaluations, encompassing articles published from 2021 onward.

High throughput drug screening platform utilizing capillary and artery cell layered models based on tumor-vascular cell interactions

Interactions between tumors and adjacent blood vessels are critical in the tumor microenvironment (TME) for influencing angiogenesis and hematogenous metastasis. Understanding these interactions within the native TME is vital for targeting various tumors, including brain tumors, due to the complexities of the blood-brain barrier. Developing an accurate tumor model that includes cell-cell and cell-matrix interactions, as well as blood flow-induced shear stress, is essential for high-throughput screening (HTS) of anti-cancer drugs. Here, we developed a glioblastoma (GBM) model surrounded by vascular cells. The arterial model was constructed by encapsulating GBM spheroids with layers of human smooth muscle cells (SMCs) and human umbilical vein endothelial cells (HUVECs), while the capillary cell layered model used only HUVECs. Comparative analysis with tumors from different organs revealed the significant role for platelet endothelial cell adhesion molecule (PECAM) in GBM-blood vascular cell interactions. Cytokine secretion analysis demonstrated PECAM's impact on tumor-specific angiogenic potential. Testing with anti-cancer drugs revealed increased expression of PECAM-associated proteins, drug resistance cytokines, and genes associated with tumor progression and metastasis. Additionally, we developed a HTS platform by encapsulating these tumor models in hydrogels and subjecting them to media circulation, effectively mimicking the dynamic TME, suitable for cancer treatment research and drug development.

Multifunctional nanoparticle-mediated targeting of metabolic reprogramming and DNA damage response pathways to treat drug-resistant triple-negative breast cancer

Multi-drug resistance and immunosuppressive triple-negative breast cancer (TNBC) is triggered by the Warburg effect, which promotes homologous recombination repair (HRR) and upregulates expression of P-glycoprotein (P-gp), in turn preventing DNA damage from chemotherapy and creating an immunosuppressive microenvironment. It is therefore of clinical relevance to develop an effective delivery system that targets metabolic reprogramming and DNA damage response pathways for the treatment of drug-resistant TNBC. Herein, a P-gp-inhibiting and GSH-responsive multifunctional drug carrier targeting integrin αvβ3 was synthesised for the delivery of Lonidamine-prodrug (M1, glycolysis inhibitor) and Senaparib (Se, Poly [ADP-ribose] polymerase inhibitor). The nanodrug delivery system (iPR@M1/Se nanoparticles) exhibit effective tumour penetration and P-gp inhibition, effectively inducing DNA damage and apoptosis in Olaparib-resistant TNBC cells in vitro, as well as a higher tumour inhibitory rate compared with that of Se (81.82 % ± 2.31 % vs 43.91 % ± 4.65 %) in vivo. Mechanistically, iPR@M1/Se nanoparticles not only reshaped the immunosuppressive microenvironment resulting from tumour glycolysis, but also downregulated the expression of HRR-related protein, fostering the cytoplasmic accumulation of DNA damage fragments, which induced activation of the cyclic GMP-AMP synthase (cGAS)/stimulator of interferon gene (STING) pathway. Experimental results show that iPR@M1/Se nanoparticles effectively promote dendritic cell maturation and T lymphocyte activation, which elicits long-term immune memory responses, and prevents tumour recurrence and lung metastasis. Therefore, these multifunctional nanoparticles have great potential and provide a clinically relevant and valuable option for Olaparib-resistant TNBC.

Discovery of novel small molecules targeting TGF-β signaling for the treatment of non-small cell lung cancer

Acquired resistance to tyrosine kinase inhibitors (TKIs) has become a significant challenge in cancer therapy, underscoring the urgent need for developing alternative therapeutic targets to relieve it. Targeting TGF-β signaling pathway has been emerging as a promising antitumor strategy due to its pivotal role in cancer progression and metastasis. Our previous study identified YR-290 as an anticancer molecule through inhibiting TGF-β signaling, but its poor solubility limited its subsequent development. To addressed the limitations, a new series of YR-290 analogues containing hydrophilic moieties were synthesized and evaluated to improve solubility and potency. The optimal compound 8dc, whose solubility also promoted over 4.7-fold compared to YR-290, showed significant inhibition with IC50 values of 0.05 and 0.09 μM in A549 and NCI-H441, respectively. In addition, 8dc remarkably exhibited anti-NSCLC activities in colony formation, migration and invasion with a concentration-dependent manner in vitro. It also affected cell cycle and induced cell apoptosis in A549 cells. More importantly, 8dc suppressed tumor growth in vivo with minimum toxicity. Mechanism study showed that 8dc exerted anticancer bioactivity by inhibition against TGF-β signaling.

The latest applications of exosome-mediated drug delivery in anticancer therapies

In recent years, the significant role of anticancer drugs in cancer treatment has garnered considerable attention. However, the application of these drugs is largely limited by their short half-life in blood circulation, low cellular uptake efficiency, and off-target effects. Exosomes, which serve as crucial messengers in intercellular communication, exhibit unique advantages in molecular delivery compared to traditional synthetic carriers, thereby offering new possibilities for modern drug delivery systems. Exosomes possess organotropic functions and are naturally produced by cells, making them promising candidates for natural drug delivery systems with organotropic properties and minimal side effects. These naturally derived carriers can achieve stable, efficient, and selective delivery of anticancer drugs, thereby enhancing the efficacy and potential of anticancer agents in cancer immunotherapy. This review provides a concise overview of the unique characteristics of exosomes related to anticancer drug delivery, strategies for utilizing exosomes as carriers in cancer therapy, and the latest advancements in the field.

A comprehensive review on overcoming the multifaceted challenge of cancer multidrug resistance: The emerging role of mesoporous silica nanoparticles

Multidrug resistance (MDR) is a significant challenge in tumor treatment, severely reducing the effectiveness of anticancer drugs and contributing to high mortality rates. This article overviews the various factors involved in the development of MDR, such as changes in drug targets, increased DNA repair mechanisms, and the impact of the tumor microenvironment. It also emphasizes the potential of mesoporous silica nanoparticles (MSNs) as a drug delivery system to combat MDR. With their unique characteristics-such as a high surface area, adjustable pore sizes, and the ability to be functionalized for targeted delivery-MSNs serve as excellent carriers for the simultaneous delivery of chemotherapeutics and siRNAs aimed at reversing resistance pathways. The paper focuses on innovative methods using MSNs for direct intranuclear delivery of their cargos to overcome efflux barrier and improve the effectiveness of combination therapies. This review highlights a promising approach for enhancing cancer treatment outcomes by integrating advanced nanotechnology with traditional therapies, addressing the ongoing challenge of MDR in oncology.

Transient intracellular expression of PD-L1 and VEGFR2 bispecific nanobody in cancer cells inspires long-term T cell activation and infiltration to combat tumor and inhibit cancer metastasis

BACKGROUND

PD-L1, an immune checkpoint inhibitor, and VEGFR2, essential for cancer metastasis, play pivotal roles in tumorigenesis. However, their miniature bispecific intracellular nanobodies for combining check-point blockade and anti-metastasis anticancer therapy remain underexplored.

METHODS

The intrabodies were developed using gene cloning technology. Specificity of the intrabodies was testified using Western blot, co-immunoprecipitation (co-IP) analysis, antibody competitive binding assay, flow cytometry analysis, etc. Checkpoint blockade was demonstrated using antibody-antigen competitive binding assay. Cancer cell migration was determined using scratch assay. Combined anti-cancer therapeutic efficacy of FAP1V2 was determined in vivo of mice models. The PD-1hi immune cells, TCR βhi and CD25hi T-cells were analyzed by flow cytometry, and cancer cell metastasis was performed using immune-fluorescence analysis on lung and liver tissues. Transcriptome analysis was performed to explore signaling pathways associated with the enhanced anticancer efficiency.

RESULTS

Bispecific intrabody FAP1V2 fused with antibody VH regions, was successfully developed and verified with its ability to target and block human and mouse PD-L1 and VEGFR2, inhibiting cancer cell binding to PD-1 and reducing their migratory capacity. Compared to the other treatment, two-rounds of transient FAP1V2 expression in LLC cells in experimental mice models achieved remarkable tumor inhibition, which brought about complete immune inhibition on growth of secondary-round of LLC tumor in 1/6 of the tested mice, inspired long-term activation of TCR βhi T cells and increased their infiltration to tumors, inhibited the emergence of PD-1hi immune cells, indicating prevented T cell depletion. The elevated CD25 expression also supported the success in enhancing immune response reported by elevated T cell activity in spleen. Transcriptome analysis identified critical intracellular pathways regulated by the concurrent blockade of PD-L1 and VEGFR2.

CONCLUSION

PD-L1 and VEGFR2- bispecific VH intracellular nanobody was highly biocompatible and showed the potential for combined anti-cancer therapy through long-term immune activation mediated by PD-L1/PD-1 checkpoint blockade and anti-metastasis mediated by VEGFR2 blockade.

Development of indole hybrids for potential lung cancer treatment - part II

Lung cancer has become the most prevalent cancer for the past three decades, and the 5-years survival rate of lung cancer is only ~20% nowadays. Chemotherapy is the mainstay of lung cancer therapy, especially for non-small cell lung cancer. However, drug resistance represents a principal cause of therapeutic failure in non-small cell lung cancer leading to therapeutic insensitivity, tumor recurrence, and disease progression. Indole hybrids have the potential to conquer drug resistance, enhance efficacy, reduce adverse events, and improve pharmacokinetic properties due to their capacity to inhibit multiple targets simultaneously. Moreover, indole hybrids osimertinib, mobocertinib, cediranib, and vizimpro are currently applied in clinics for lung cancer therapy, demonstrating that indole hybrids are valuable scaffolds in the treatment and eradication of lung cancer. This review provides a comprehensive overview of the evolving landscape of indole hybrids with the in vitro and in vivo efficacy against lung cancer, and the structure-activity relationships as well as mechanisms of action are also discussed, covering articles published from 2021 onward.

A hyaluronic acid modified copper-based metal-organic framework overcomes multidrug resistance via two-way redox dyshomeostasis under hypoxia

Multidrug resistance (MDR) has become a major challenge in tumor chemotherapy, primarily associated with the overexpression of P-glycoprotein (P-gp). Inhibiting P-gp expression and function through redox dyshomeostasis has shown great potential for reversing MDR. Here, a nanoscale system of copper-based metal-organic framework (HA-CuMOF@DOX) modified with hyaluronic acid (HA) was constructed to overcome MDR via two-way regulation of redox homeostasis under hypoxia. HA-CuMOF@DOX is a spherical glutathione (GSH) responsive nanoparticle with a drug loading capacity of 20.69 %, which could deplete GSH through Cu2+ and electrophilic ligands, and generate •OH via a Fenton-like reaction. In vitro experiments suggested that the nanoparticles had good targetability to cancer cells and biocompatibility to normal cells. HA-CuMOF@DOX was successfully internalized by drug-resistant human hepatoma carcinoma cell line (HepG2-ADR). It aggravated redox dyshomeostasis via dual regulation, inducing mitochondrial damage, reducing intracellular adenosine triphosphate (ATP) levels, and downregulating P-gp to overcome HepG2-ADR drug resistance. More importantly, in vivo experiments demonstrated an 80.69 % tumor growth inhibition in nude mice bearing HepG2-ADR cells. This work represents a significant advancement in the development of effective treatments for drug-resistant tumors.

Development of indole hybrids for potential lung cancer treatment-part I: nitrogen-containing six-membered aromatic heterocycles

Lung cancer is the most prevalent invasive malignancy and the leading cause of cancer-related death. Chemotherapy is vital for lung cancer therapy, but multidrug resistance is responsible for the majority of lung cancer fatalities, creating an imperative demand to develop novel chemotherapeutics. Indole is a valuable anti-lung cancer pharmacophore since its derivatives could act on lung cancer cells through various mechanisms. Notably, indole hybrids could inhibit multiple targets simultaneously and have the potential to overcome the shortcomings of traditional chemotherapeutics. Moreover, many indole hybrids such as the indole-pyrimidine hybrid osimertinib and the indole-hydroxamic acid hybrid panobinostat, are either under clinical evaluations or have already been approved for lung cancer therapy. This indicates that the rational design of indole hybrids represents a highly prospective approach for the development of new anti-lung cancer chemotherapeutic agents. This review focuses on exploring the anti-lung cancer therapeutic potential of indole hybrids and delves into their action mechanisms as well as structure-activity correlations, covering articles published between 2021 and present. The ultimate goal is to offer a foundation for the rational design of indole hybrids in the future.

Reversal potentials of Tween 20 in ABC transporter-mediated multidrug-resistant cancer and treatment-resistant depression through interacting with both drug-binding and ATP-binding areas on MDR proteins

Drug efflux transporters, especially those belonging to the ATP-binding cassette (ABC) transporter superfamily, play a crucial role in various drug resistance issues, including multidrug resistance (MDR) in cancer and treatment-resistant depression (TRD) in individuals with major depressive disorder. Key transporters in this context include P-glycoprotein (P-gp), multidrug resistance protein 1 (MRP1), and breast cancer resistance protein (BCRP). This study aimed to investigate the modulatory effects of polyoxyethylene (20) sorbitan monolaurate (Tween 20) on these efflux transporters in vitro and to evaluate its potential for overcoming drug resistance in two models: an in vitro cancer MDR model and an in vivo TRD model. The findings indicated that 0.001% Tween 20 significantly inhibited the efflux actions of all three transporters. Additionally, 0.005% Tween 20 effectively reversed resistance to paclitaxel, vincristine, doxorubicin, and mitoxantrone in various cancer MDR cell lines. In the in vivo depression-like behaviour model, 0.01% Tween 20 markedly enhanced the antidepressant and anxiolytic effects of fluoxetine. Given its strong inhibitory effects on P-gp, MRP1, and BCRP, along with its capacity to reverse drug resistance both in vitro and in vivo, Tween 20 is a compelling candidate for tackling transporter-mediated drug resistance.

CDK5-triggered G6PD phosphorylation at threonine 91 facilitating redox homeostasis reveals a vulnerability in breast cancer

Glucose-6-phosphate dehydrogenase (G6PD), the first rate-limiting enzyme of the pentose phosphate pathway (PPP), is aberrantly activated in multiple types of human cancers, governing the progression of tumor cells as well as the efficacy of anticancer therapy. Here, we discovered that cyclin-dependent kinase 5 (CDK5) rewired glucose metabolism from glycolysis to PPP in breast cancer (BC) cells by activating G6PD to keep intracellular redox homeostasis under oxidative stress. Mechanistically, CDK5-phosphorylated G6PD at Thr-91 facilitated the assembly of inactive monomers of G6PD into active dimers. More importantly, CDK5-induced pho-G6PD was explicitly observed specifically in tumor tissues in human BC specimens. Pharmacological inhibition of CDK5 remarkably abrogated G6PD phosphorylation, attenuated tumor growth and metastasis, and synergistically sensitized BC cells to poly-ADP-ribose polymerase (PARP) inhibitor Olaparib, in xenograft mouse models. Collectively, our results establish the crucial role of CDK5-mediated phosphorylation of G6PD in BC growth and metastasis and provide a therapeutic regimen for BC treatment.

Natural polymer derivative-based pH-responsive nanoformulations with entrapped diketo-tautomers of 5-fluorouracil for enhanced cancer therapy

Background and purpose

Despite significant advancements in cancer therapies, chemotherapeutics continue to be the mainstay for treating cancer patients, with 5-fluorouracil (5-FU) being commonly used for various cancers. However, its limited ability to penetrate cell membranes and its short half-life, caused by rapid metabolism, necessitate frequent administration of high doses to maintain effective therapeutic levels. This study aimed to synthesize oxidized sodium alginate (OSA) derivatives to create OSA nanoparticles loaded with 5-FU (OSANP@ 5-FU), promoting diketo tautomers, and evaluate their photophysical properties, release profile, and anticancer activity with minimal toxicity.

Experimental approach

The investigation encompassed physicochemical characterization, encapsulation efficiency, 5-FU release kinetics at pH 2.2 and 7.4, cell viability assessment via MTT assay in V79 cells, and in vitro anticancer efficacy in the A375 cell line.

Key results

Steady-state absorption and emission confirmed the presence of advantageous diketone tautomers of 5-FU, indicating radiative transitions from the second singlet excited state to the ground state (S2→S0) and the drug's encapsulation within the polymeric nanostructure. Dynamic light scattering revealed that OSA nanoparticles, initially 177.8 nm, grew to 226.6 nm after encapsulating 5-FU, retaining high zeta potential for stability. With a 68% encapsulation efficiency, in vitro studies showed 46 to 54 % of 5-FU released across different pH levels within 510 minutes.

Conclusion

In acidic conditions, there is a greater release of 5-FU than neutral pH levels, indicating a pH-responsive release profile beneficial for cancer treatment, with the release mechanism of OSANPs following Fickian diffusion as identified by a Korsmeyer-Peppas mathematical model and the formulation showing improved therapeutic efficacy.

Acquired resistance to tyrosine kinase targeted therapy: mechanism and tackling strategies

Over the past two decades, tyrosine kinase inhibitors (TKIs) have rapidly emerged as pivotal targeted agents, offering promising therapeutic prospects for patients. However, as the cornerstone of targeted therapies, an increasing number of TKIs have been found to develop acquired resistance during treatment, making the challenge of overcoming this resistance a primary focus of current research. This review comprehensively examines the evolution of TKIs from multiple perspectives, with particular emphasis on the mechanisms underlying acquired resistance, innovative drug design strategies, inherent challenges, and future directions.

Targeted Drug Nanodelivery and Immunotherapy for Combating Tumor Resistance

Chemotherapy resistance is a common cause of tumor treatment failure. Various molecular responses, such as increased expression of efflux transporter proteins, including Pglycoprotein (P-gp), changes in the tumor microenvironment (TME), the role of platelets, and the effects of cancer stem cells (CSCs), can lead to drug resistance. Through extensive research on the mechanisms of drug resistance, more effective anti-resistance drugs and therapeutic approaches are being developed. This review explores drug resistance mechanisms and summarizes relevant anti-resistance drugs. In addition, due to the therapeutic limitations of the aforementioned treatments, new advances in nanocarrier-based combination immunotherapy to address the challenge of drug resistance have been described. Nanocarriers combined with immunotherapy can not only target tumor sites for targeted drug release but also modulate the autoimmune system and enhance immune efficacy, thereby overcoming tumor drug resistance. This review suggests new strategies for overcoming tumor drug resistance and is expected to inform tumor treatment and prognosis.

Effect of immunotherapy or anti-angiogenesis therapy combined with chemotherapy for advanced triple-negative breast cancer: A real-world retrospective study

BACKGROUND

Immune checkpoint inhibitors combined with chemotherapy (ICI-chemo) and anti-angiogenesis therapy combined with chemotherapy (anti-angio-chemo) have demonstrated superiority over traditional chemotherapy in patients with advanced triple-negative breast cancer (TNBC). However, due to the absence of a direct comparison between ICI-chemo and anti-angio-chemo, it remains unclear which treatment is superior.

OBJECTIVE

This study aimed to investigate the efficacy and safety of ICI-chemo or anti-angio-chemo for advanced TNBC at Sun Yat-sen University Cancer Center.

METHODS

A retrospective analysis was conducted on the medical records of advanced TNBC patients who received ICI-chemo or anti-angio-chemo treatment between January 2017 and March 2023. Survival outcomes and safety profiles were evaluated.

RESULTS

A total of 178 patients were enrolled, including 101 who received ICI-chemo and 77 who received anti-angio-chemo. The median follow-up time was 19.93 months [95 % confidence interval (CI): 17.05-22.81]. There was no significant difference in patient outcomes, including progression-free survival (PFS), overall survival (OS), objective response rate (ORR), and disease control rate (DCR) between the two treatment regimens in the overall population. However, ICI-chemo demonstrated clinical survival benefits, with significant improvements in PFS and OS [hazard ratio (HR) = 0. 546, P = 0.048; HR = 0.313, P = 0.032] in patients receiving first-line treatment. The median PFS (mPFS) for the ICI-chemo and anti-angio-chemo cohorts was 9.37 and 6.03 months, respectively. Univariate and multivariate analyses showed that ICI-chemo independently achieved favorable PFS. No statistically significant difference was observed in PFS or OS between patients who received second-line or later ICI-chemo or anti-angio-chemo. The mPFS was 4.83 and 5.03 months, respectively. The toxicity profiles of adverse events were similar across two cohorts.

CONCLUSION

Among patients with advanced TNBC, ICI-chemo is associated with potentially longer survival compared to anti-angio-chemo as first-line treatment. Given their efficacy and better cost-effectiveness, these two treatment regimens may be considered potentially effective options for second-line therapy and beyond.

AKR1C1 interacts with STAT3 to increase intracellular glutathione and confers resistance to oxaliplatin in colorectal cancer

Oxaliplatin (OXA), a platinum-based chemotherapeutic agent, remains a mainstay in first-line treatments for advanced colorectal cancer (CRC). However, the eventual development of OXA resistance represents a significant clinical challenge. In the present study, we demonstrate that the aldo-keto reductase 1C1 (AKR1C1) is overexpressed in CRC cells upon acquisition of OXA resistance, evident in OXA-resistant CRC cell lines. We employed genetic silencing and pharmacological inhibition strategies to establish that suppression of AKR1C1 restores OXA sensitivity. Mechanistically, AKR1C1 interacts with and activates the transcription factor STAT3, which upregulates the glutamate transporter EAAT3, thereby elevating intracellular glutathione levels and conferring OXA resistance. Alantolactone, a potent natural product inhibitor of AKR1C1, effectively reverses this chemoresistance, restricting the growth of OXA-resistant CRC cells both in vitro and in vivo. Our findings uncover a critical AKR1C1-dependent mechanism behind OXA resistance and propose a promising combinatorial therapeutic strategy to overcome this resistance in CRC.

Role of ABCC5 in cancer drug resistance and its potential as a therapeutic target

Over 90% of treatment failures in cancer therapy can be attributed to multidrug resistance (MDR), which can develop intracellularly or through various routes. Numerous pathways contribute to treatment resistance in cancer, but one of the most significant pathways is intracellular drug efflux and reduced drug concentrations within cells, which are controlled by overexpressed drug efflux pumps. As a member of the family of ABC transporter proteins, ABCC5 (ATP Binding Cassette Subfamily C Member 5) reduces the intracellular concentration of a drug and its subsequent effectiveness using an ATP-dependent method to pump the drug out of the cell. Numerous studies have demonstrated that ABCC5 is strongly linked to both poor prognosis and poor treatment response. In addition, elevated ABCC5 expression is noted in a wide variety of malignancies. Given that ABCC5 is regulated by several pathways in a broad range of cancer types, it is a prospective target for cancer treatment. This review examined the expression, structure, function, and role of ABCC5 in various cancer types.

Discovery of novel pyrazolo[1,5-a]pyrimidine derivatives as potent reversal agents against ABCB1-mediated multidrug resistance

The P-glycoprotein (ABCB1)-mediated multidrug resistance (MDR) has emerged as a significant impediment to the efficacy of cancer chemotherapy in clinical therapy, which could promote the development of effective agents for MDR reversal. In this work, we reported the exploration of novel pyrazolo [1,5-a]pyrimidine derivatives as potent reversal agents capable of enhancing the sensitivity of ABCB1-mediated MDR MCF-7/ADR cells to paclitaxel (PTX). Among them, compound 16q remarkably increased the sensitivity of MCF-7/ADR cells to PTX at 5 μM (IC50 = 27.00 nM, RF = 247.40) and 10 μM (IC50 = 10.07 nM, RF = 663.44). Compound 16q could effectively bind and stabilize ABCB1, and does not affect the expression and subcellular localization of ABCB1 in MCF-7/ADR cells. Compound 16q inhibited the function of ABCB1, thereby increasing PTX accumulation, and interrupting the accumulation and efflux of the ABCB1-mediated Rh123, thus resulting in exhibiting good reversal effects. In addition, due to the potent reversal effects of compound 16q, the abilities of PTX to inhibit tubulin depolymerization, and induce cell cycle arrest and apoptosis in MCF-7/ADR cells under low-dose conditions were restored. These results indicate that compound 16q might be a promising potent reversal agent capable of revising ABCB1-mediated MDR, and pyrazolo [1,5-a]pyrimidine might represent a novel scaffold for the discovery of new ABCB1-mediated MDR reversal agents.

IGFBP7 regulates cell proliferation and migration through JAK/STAT pathway in gastric cancer and is regulated by DNA and RNA methylation

New biomarkers for early diagnosis of gastric cancer (GC), the second leading cause of cancer-related death, are urgently needed. IGFBP7, known to play various roles in multiple tumours, is complexly regulated across diverse cancer types, as evidenced by our pancancer analysis. Bioinformatics analysis revealed that IGFBP7 expression was related to patient prognosis, tumour clinicopathological characteristics, tumour stemness, microsatellite instability and immune cell infiltration, as well as the expression of oncogenes and immune checkpoints. GSEA links IGFBP7 to several cancer-related pathways. IGFBP7 deficiency inhibited GC cell proliferation and migration in vitro. Furthermore, an in vivo nude mouse model revealed that IGFBP7 downregulation suppressed the tumorigenesis of GC cells. Western blotting analysis showed that the JAK1/2-specific inhibitor ruxolitinib could rescue alterations induced by IGFBP7 overexpression in GC cells. Additionally, our bioinformatics analysis and in vitro assays suggested that IGFBP7 is regulated by DNA methylation at the genetic level and that the RNA m6A demethylase FTO modulates it at the posttranscriptional level. This study emphasizes the clinical relevance of IGFBP7 in GC and its influence on cell proliferation and migration via the JAK/STAT signalling pathway. This study also highlights the regulation of IGFBP7 in GC by DNA and m6A RNA methylation.

Neighboring Effect-Initiated Supramolecular Nanocomplex with Sequential Infiltration as Irreversible Apoptosis Inducer for Synergetic Chemo-Immunotherapy

Chemotherapy-based combination regimens are recommended as first-line treatment for colorectal cancer. However, multidrug resistance (MDR) and limited drug infiltration in tumor microenvironment remain critical challenges. Herein, a pH/redox dual activated supramolecular DAS@CD-OxPt (IV) nanoparticles (NPs) via host-guest molecular recognition to achieve relay drugs delivery of active oxaliplatin (OxPt (IV)) and Src inhibitor dasatinib (DAS) between tumor cells is developed. DAS@CD-OxPt (IV) NPs exhibit prolonged circulation in the blood and intra-tumoral retention. Triggered by the endo/lysosome (pH 5.0), flexible DAS@CD-OxPt (IV) NPs exhibited proton-driven in situ assembly to form nanofiber in tumor cells. Dual chemotherapeutic agents released from DAS@CD-OxPt (IV) NPs synergistically cause irreversible DNA damage by blocking p53-mediated DNA repair. Supramolecular nanofibers can further serve as the "ammunition depot" to continuously release drugs from dying cells and transport them into neighboring tumor cells, leading to domino-like cell death and enhanced immunogenicity. Furthermore, DAS@CD-OxPt (IV) NPs combined with immune checkpoint blockade (ICB) therapy strikingly suppress CT26 tumor growth and pulmonary metastasis.

A promising future of metal-N-heterocyclic carbene complexes in medicinal chemistry: The emerging bioorganometallic antitumor agents

Metal complexes based on N-heterocyclic carbene (NHC) ligands have emerged as promising broad-spectrum antitumor agents in bioorganometallic medicinal chemistry. In recent decades, studies on cytotoxic metal-NHC complexes have yielded numerous compounds exhibiting superior cytotoxicity compared to cisplatin. Although the molecular mechanisms of these anticancer complexes are not fully understood, some potential targets and modes of action have been identified. However, a comprehensive review of their biological mechanisms is currently absent. In general, apoptosis caused by metal-NHCs is common in tumor cells. They can cause a series of changes after entering cells, such as mitochondrial membrane potential (MMP) variation, reactive oxygen species (ROS) generation, cytochrome c (cyt c) release, endoplasmic reticulum (ER) stress, lysosome damage, and caspase activation, ultimately leading to apoptosis. Therefore, a detailed understanding of the influence of metal-NHCs on cancer cell apoptosis is crucial. In this review, we provide a comprehensive summary of recent advances in metal-NHC complexes that trigger apoptotic cell death via different apoptosis-related targets or signaling pathways, including B-cell lymphoma 2 (Bcl-2 family), p53, cyt c, ER stress, lysosome damage, thioredoxin reductase (TrxR) inhibition, and so forth. We also discuss the challenges, limitations, and future directions of metal-NHC complexes to elucidate their emerging application in medicinal chemistry.

Aptamer functionalized hypoxia-potentiating agent and hypoxia-inducible factor inhibitor combined with hypoxia-activated prodrug for enhanced tumor therapy

Triple-negative breast cancer (TNBC) is the most lethal subtype of breast cancer. Hypoxia-activated prodrugs (HAPs) have shown promise as potential therapeutic agents for TNBC. While increasing hypoxia levels may promote the HAP activation, it raises concerns regarding HIF1α-dependent drug resistance. It is desirable to develop a targeted approach that enhances tumor hypoxia for HAP activation without promoting HIF1α-dependent drug resistance in TNBC treatment. Herein, we proposed a multi-responsive carrier-free self-assembled nanomedicine named AQ4N@CA4T1ASO. This nanomedicine first targeted tumors by the TNBC-targeting aptamers (T1), and then disassembled in the reductive and acidic conditions within tumors. The released Combretastatin 4 (CA4) could exacerbate hypoxia, thereby promoting the conversion of inactive Banoxantrone (AQ4N) to its active form, AQ4. Simultaneously, the released antisense oligonucleotide (ASO) could attenuate hypoxia-induced HIF1α mRNA expression, thereby sensitizing the tumor to chemotherapy. Overall, this smart nanomedicine represents a profound targeted therapy strategy, combining "hypoxia-potentiating, hypoxia-activated, chemo-sensitization" approaches for TNBC treatment. In vivo study demonstrated significant suppression of tumor growth, highlighting the promising potential of this nanomedicine for future clinical translation.

Overcoming Cancer Drug Resistance with Nanoparticle Strategies for Key Protein Inhibition

Drug resistance remains a critical barrier in cancer therapy, diminishing the effectiveness of chemotherapeutic, targeted, and immunotherapeutic agents. Overexpression of proteins such as B-cell lymphoma 2 (Bcl-2), inhibitor of apoptosis proteins (IAPs), protein kinase B (Akt), and P-glycoprotein (P-gp) in various cancers leads to resistance by inhibiting apoptosis, enhancing cell survival, and expelling drugs. Although several inhibitors targeting these proteins have been developed, their clinical use is often hampered by systemic toxicity, poor bioavailability, and resistance development. Nanoparticle-based drug delivery systems present a promising solution by improving drug solubility, stability, and targeted delivery. These systems leverage the Enhanced Permeation and Retention (EPR) effect to accumulate in tumor tissues, reducing off-target toxicity and increasing therapeutic efficacy. Co-encapsulation strategies involving anticancer drugs and resistance inhibitors within nanoparticles have shown potential in achieving coordinated pharmacokinetic and pharmacodynamic profiles. This review discusses the mechanisms of drug resistance, the limitations of current inhibitors, and the advantages of nanoparticle delivery systems in overcoming these challenges. By advancing these technologies, we can enhance treatment outcomes and move towards more effective cancer therapies.

Novel pyxinol amide derivatives bearing an aliphatic heterocycle as P-glycoprotein modulators for overcoming multidrug resistance

P-glycoprotein (Pgp) modulators are promising agents for overcoming multidrug resistance (MDR) in cancer chemotherapy. In this study, via structural optimization of our lead compound S54 (nonsubstrate allosteric inhibitor of Pgp), 29 novel pyxinol amide derivatives bearing an aliphatic heterocycle were designed, synthesized, and screened for MDR reversal activity in KBV cells. Unlike S54, these active derivatives were shown to transport substrates of Pgp. The most potent derivative 4c exhibited promising MDR reversal activity (IC50 of paclitaxel = 8.80 ± 0.56 nM, reversal fold = 211.8), which was slightly better than that of third-generation Pgp modulator tariquidar (IC50 of paclitaxel = 9.02 ± 0.35 nM, reversal fold = 206.6). Moreover, the cytotoxicity of this derivative was 8-fold lower than that of tariquidar in human normal HK-2 cells. Furthermore, 4c blocked the efflux function of Pgp and displayed high selectivity for Pgp but had no effect on its expression and distribution. Molecular docking revealed that 4c bound preferentially to the drug-binding domain of Pgp. Overall, 4c is a promising lead compound for developing Pgp modulators.

Cisplatin-based miRNA delivery strategy inspired by the circCPNE1/miR-330-3p pathway for oral squamous cell carcinoma

Circular RNAs (circRNAs) are ideal biomarkers of oral squamous cell carcinoma (OSCC) because of their highly stable closed-loop structure, and they can act as microRNA (miRNA) sponges to regulate OSCC progression. By analyzing clinical samples, we identified circCPNE1, a dysregulated circRNA in OSCC, and its expression level was negatively correlated with the clinical stage of OSCC patients. Gain-of-function assays revealed the tumor-suppressive effect of circCPNE1, which was then identified as a miR-330-3p sponge. MiR-330-3p was recognized as a tumor promoter in multiple studies, consistent with our finding that it could promote the proliferation, migration, and invasion of OSCC cells. These results indicated that selective inhibition of miR-330-3p could be an effective strategy to inhibit OSCC progression. Therefore, we designed cationic polylysine-cisplatin prodrugs to deliver antagomiR-330-3p (a miRNA inhibitory analog) via electrostatic interactions to form PP@miR nanoparticles (NPs). Paratumoral administration results revealed that PP@miR NPs effectively inhibited subcutaneous tumor progression and achieved partial tumor elimination (2/5), which confirmed the critical role of miR-330-3p in OSCC development. These findings provide a new perspective for the development of OSCC treatments.

Progressive enhanced photodynamic therapy and enhanced chemotherapy fighting against malignant tumors with sequential drug release

During the process of malignant tumor treatment, photodynamic therapy (PDT) exerts poor efficacy due to the hypoxic environment of the tumor cells, and long-time chemotherapy reduces the sensitivity of tumor cells to chemotherapy drugs due to the presence of drug-resistant proteins on the cell membranes for drug outward transportation. Therefore, we reported a nano platform based on mesoporous silica coated with polydopamine (MSN@PDA) loading PDT enhancer MnO2, photosensitizer indocyanine green (ICG) and chemotherapeutic drug doxorubicin (DOX) (designated as DMPIM) to achieve a sequential release of different drugs to enhance treatment of malignant tumors. MSN was first synthesized by a template method, then DOX was loaded into the mesoporous channels of MSN, and locked by the PDA coating. Next, ICG was modified by π-π stacking on PDA, and finally, MnO2layer was accumulated on the surface of DOX@MSN@PDA- ICG@MnO2, achieving orthogonal loading and sequential release of different drugs. DMPIM first generated oxygen (O2) through the reaction between MnO2and H2O2after entering tumor cells, alleviating the hypoxic environment of tumors and enhancing the PDT effect of sequentially released ICG. Afterwards, ICG reacted with O2in tumor tissue to produce reactive oxygen species, promoting lysosomal escape of drugs and inactivation of p-glycoprotein (p-gp) on tumor cell membranes. DOX loaded in the MSN channels exhibited a delay of approximately 8 h after ICG release to exert the enhanced chemotherapy effect. The drug delivery system achieved effective sequential release and multimodal combination therapy, which achieved ideal therapeutic effects on malignant tumors. This work offers a route to a sequential drug release for advancing the treatment of malignant tumors.

The anticancer therapeutic potential of pyrimidine-sulfonamide hybrids

Cancer as a devastating malignancy, seriously threatens human life and health, but most chemotherapeutics have long been criticized for unsatisfactory therapeutic efficacy due to drug resistance and severe off-target toxicity. Pyrimidines, including fused pyrimidines, are privileged scaffolds for various biological cancer targets and are the most important class of metalloenzyme carbonic anhydrase inhibitors. Pyrimidine-sulfonamide hybrids can act on different targets in cancer cells simultaneously and possess potent activity against various cancers, revealing that hybridization of pyrimidine with sulfonamide is a promising approach to generate novel effective anticancer candidates. This review aims to summarize the recent progress of pyrimidine-sulfonamide hybrids with anticancer potential, covering papers published from 2020 to present, to facilitate further rational design of more effective candidates.

An insight into the dual role of MoS2-based nanocarriers in anticancer drug delivery and therapy

Over the years, nanomaterials have been exploited as drug delivery systems and therapeutic agents in cancer treatment. Special emphasis has been placed on structure and shape-mediated drug loading and release. Functional materials, including molybdenum disulfide (MoS2), have shown promising results because of their tunable structure and unmatched physicochemical properties. Specifically, easy surface functionalization and high drug adsorption ability make them ideal candidates. Although the large surface area of nanosheets/nanoflakes may result in high drug loading, the encapsulation efficiency is better for MoS2 nanoflower structures. Due to its high targeting abilities, the loading of chemotherapeutic drugs onto MoS2 may minimize nonspecific cellular death and undesired side effects. Furthermore, due to their strong light-absorption ability, MoS2 nanostructures have been widely exploited as photothermal and photodynamic therapeutic agents. The unexplored dimensions of cancer therapy, including chemodynamic (Fenton-like reaction) and piezo-catalytic (ultrasound-mediated reactive oxygen generation), have been recently unlocked, in which the catalytic properties of MoS2 are utilized to generate toxic free radicals to eliminate cancer. Intriguingly, combining these therapeutic modalities often results in high therapeutic efficacy at low doses and minimizes side effects. With a plethora of recent studies, a thorough analysis of current findings is crucial. Therefore, this review discusses the major advances in this field of research. A brief commentary on the limitations/future outlook/ethical issues of the clinical translation of MoS2-mediated cancer treatments is also deliberated. Overall, in our observations, the MoS2-based nanoformulations hold great potential for future cancer therapy applications. STATEMENT OF SIGNIFICANCE: Development of nanomedicines based on MoS2 has opened new avenues in cancer treatment. The MoS2 with different morphologies (nanosheet/nanoflower/QDs) has shown promising results in controlled and targeted drug delivery, leading to minimized side effects and increased therapeutic efficacy. While existing reviews have primarily focused on the optical/thermal properties utilized in photodynamic/photothermal therapy, the outstanding catalytic properties of MoS2 utilized in cancer therapies (chemodynamic/piezo-catalytic) are often overlooked. This review critically highlights and praises/criticizes individual articles reporting the MoS2-based nanoplatforms for cancer therapy applications. Additionally, MoS2-based combined therapies for synergistic effects are discussed. Furthermore, a brief commentary on the future prospects for clinical translations is also deliberated, which is appealing to various research communities engaged in cancer theranostics and biomedical sciences research.

tRNA-derived small RNAs in human cancers: roles, mechanisms, and clinical application

Transfer RNA (tRNA)-derived small RNAs (tsRNAs) are a new type of non-coding RNAs (ncRNAs) produced by the specific cleavage of precursor or mature tRNAs. tsRNAs are involved in various basic biological processes such as epigenetic, transcriptional, post-transcriptional, and translation regulation, thereby affecting the occurrence and development of various human diseases, including cancers. Recent studies have shown that tsRNAs play an important role in tumorigenesis by regulating biological behaviors such as malignant proliferation, invasion and metastasis, angiogenesis, immune response, tumor resistance, and tumor metabolism reprogramming. These may be new potential targets for tumor treatment. Furthermore, tsRNAs can exist abundantly and stably in various bodily fluids (e.g., blood, serum, and urine) in the form of free or encapsulated extracellular vesicles, thereby affecting intercellular communication in the tumor microenvironment (TME). Meanwhile, their abnormal expression is closely related to the clinicopathological features of tumor patients, such as tumor staging, lymph node metastasis, and poor prognosis of tumor patients; thus, tsRNAs can be served as a novel type of liquid biopsy biomarker. This review summarizes the discovery, production, and expression of tsRNAs and analyzes their molecular mechanisms in tumor development and potential applications in tumor therapy, which may provide new strategies for early diagnosis and targeted therapy of tumors.

Natural products reverse cancer multidrug resistance

Cancer stands as a prominent global cause of death. One of the key reasons why clinical tumor chemotherapy fails is multidrug resistance (MDR). In recent decades, accumulated studies have shown how Natural Product-Derived Compounds can reverse tumor MDR. Discovering novel potential modulators to reduce tumor MDR by Natural Product-Derived Compounds has become a popular research area across the globe. Numerous studies mainly focus on natural products including flavonoids, alkaloids, terpenoids, polyphenols and coumarins for their MDR modulatory activity. Natural products reverse MDR by regulating signaling pathways or the relevant expressed protein or gene. Here we perform a deep review of the previous achievements, recent advances in the development of natural products as a treatment for MDR. This review aims to provide some insights for the study of multidrug resistance of natural products.

Utilizing non-coding RNA-mediated regulation of ATP binding cassette (ABC) transporters to overcome multidrug resistance to cancer chemotherapy

Multidrug resistance (MDR) is one of the primary factors that produces treatment failure in patients receiving cancer chemotherapy. MDR is a complex multifactorial phenomenon, characterized by a decrease or abrogation of the efficacy of a wide spectrum of anticancer drugs that are structurally and mechanistically distinct. The overexpression of the ATP-binding cassette (ABC) transporters, notably ABCG2 and ABCB1, are one of the primary mediators of MDR in cancer cells, which promotes the efflux of certain chemotherapeutic drugs from cancer cells, thereby decreasing or abolishing their therapeutic efficacy. A number of studies have suggested that non-coding RNAs (ncRNAs), particularly microRNAs (miRNAs), long non-coding RNAs (lncRNAs) and circular RNAs (circRNAs), play a pivotal role in mediating the upregulation of ABC transporters in certain MDR cancer cells. This review will provide updated information about the induction of ABC transporters due to the aberrant regulation of ncRNAs in cancer cells. We will also discuss the measurement and biological profile of circulating ncRNAs in various body fluids as potential biomarkers for predicting the response of cancer patients to chemotherapy. Sequence variations, such as alternative polyadenylation of mRNA and single nucleotide polymorphism (SNPs) at miRNA target sites, which may indicate the interaction of miRNA-mediated gene regulation with genetic variations to modulate the MDR phenotype, will be reviewed. Finally, we will highlight novel strategies that could be used to modulate ncRNAs and circumvent ABC transporter-mediated MDR.

The effect of human umbilical cord mesenchymal stem cells conditioned medium combined with tamoxifen drug on BRCA1 and BRCA2 expression in breast cancer mouse models

BACKGROUND

A growing number of studies has indicated that the expression of Breast Cancer Susceptibility Genes 1 (BRCA1) and BRCA2 contribute to the resistance to DNA-damaging chemotherapies. Tamoxifen induces tumor cell death by suppressing estrogen receptor (ER) signaling and inducing DNA damage, and BRCA1 upregulation causes Tamoxifen chemoresistance in breast cancer cells. Consequently, this research study aimed to investigate the possible therapeutic effect of Human Umbilical Cord Mesenchymal Stem Cells Conditioned Medium (UCMSCs-CM) on sensitizing breast cancer cells to Tamoxifen by regulating BRCA1 and BRCA2 expression in vivo.

METHODS

Forty female mice, 4-8 weeks old, with weight of 150 g, were used for this study. Mouse 4T1 breast tumor models were established and then treated with UCMSCs-CM and Tamoxifen alone or in combination. After 10 days, the tumor masses were collected and the expression levels of BRCA1 and BRCA2 were evaluated using qRT-PCR assay.

RESULTS

The results obtained from qRT-PCR assay illustrated that UCMSCs-CM, either alone or in combination with Tamoxifen, significantly downregulated the mRNA expression levels of BRCA1 in breast cancer mouse models. However, both UCMSCs-CM and Tamoxifen indicated no statistically significant impact on BRCA2 mRNA expression compared to controls.

CONCLUSION

Our findings evidenced that UCMSCs-CM could be considered as a potential therapeutic option to modulate Tamoxifen chemosensitivity by regulating BRCA1 in breast cancer.

Alpha-hederin reprograms multi-miRNAs activity and overcome small extracellular vesicles-mediated paclitaxel resistance in NSCLC

Background: Small extracellular vesicles (sEVs) mediate intercellular communication in the tumor microenvironment (TME) and contribute to the malignant transformation of tumors, including unrestricted growth, metastasis, or therapeutic resistance. However, there is a lack of agents targeting sEVs to overcome or reverse tumor chemotherapy resistance through sEVs-mediated TME reprogramming. Methods: The paclitaxel (PTX)-resistant A549T cell line was used to explore the inhibitory effect of alpha-hederin on impeding the transmission of chemoresistance in non-small cell lung cancer (NSCLC) through the small extracellular vesicles (sEVs) pathway. This investigation utilized the CCK-8 assay and flow cytometry. Transcriptomics, Western blot, oil red O staining, and targeted metabolomics were utilized to evaluate the impact of alpha-hederin on the expression of signaling pathways associated with chemoresistance transmission in NSCLC cells before and after treatment. In vivo molecular imaging and immunohistochemistry were conducted to assess how alpha-hederin influences the transmission of chemoresistance through the sEVs pathway. RT-PCR was employed to examine the expression of miRNA and lncRNA in response to alpha-hederin treatment. Results: The resistance to PTX chemotherapy in A549T cells was overcome by alpha-hederin through its dependence on sEV secretion. However, the effectiveness of alpha-hederin was compromised when vesicle secretion was blocked by the GW4869 inhibitor. Transcriptomic analysis for 463 upregulated genes in recipient cells exposed to A549T-derived sEVs revealed that these sEVs enhanced TGFβ signaling and unsaturated fatty acid synthesis pathways. Alpha-hederin inhibited 15 types of unsaturated fatty acid synthesis by reducing the signaling activity of the sEVs-mediated TGFβ/SMAD2 pathway. Further, we observed that alpha-hederin promoted the production of three microRNAs (miRNAs, including miR-21-5p, miR-23a-3p, and miR-125b-5p) and the sorting to sEVs in A549T cells. These miRNAs targeted the TGFβ/SMADs signaling activity in sEVs-recipient cells and sensitized them to the PTX therapy. Conclusion: Our finding demonstrated that alpha-hederin could sensitize PTX-resistant NSCLC cells by sEV-mediated multiple miRNAs accumulation, and inhibiting TGFβ/SMAD2 pathways in recipient cells.

Synergistic effects of multidrug/material combination deliver system for anti-mutidrug-resistant tumor

Multidrug resistance (MDR) is a public health issue of particular concern, for which nanotechnology-based multidrug delivery systems are considered among the most effective suppressive strategies for such resistance in tumors. However, for such strategies to be viable, the notable shortcomings of reduced loading efficiency and uncontrollable drug release ratio need to be addressed. To this end, we developed a novel "multidrug/material" co-delivery system, using d-α-tocopheryl polyethylene glycol 1000 succinate (TPGS, P-gp efflux pump inhibitor) and poly(amidoamine) (PAMAM) to fabricate a precursor material with the properties of reversing MDR and having a long-cycle. Further, to facilitate multidrug co-delivery, we loaded doxorubicin(Dox) and curcumin(Cur, cardiotoxicity modifier and P-gp inhibitor) into PAMAM-TPGS nano-micelles respectively, and mixed in appropriate proportions. The multidrug/material co-delivery system thus obtained was characterized by high drug loading and a controllable drug release ratio in the physiological environment. More importantly, in vitro and in vivo pharmacodynamic studies indicated that the multidrug/material co-delivery system facilitated the reversal of MDR. Moreover, the system has increased anti-tumor activity and is biologically safe. We accordingly propose that the "multidrug/material" co-delivery system developed in this study could serve as a potential platform for reversing MDR and achieving safe and effective clinical treatment.

Correlation between microbial characteristics and reproductive status of the yak uterus based on macrogenomic analysis

INTRODUCTION

This study aimed to investigate the microbial characteristics of yak uteri collected using intrauterine cotton swabs (CS) during different reproductive stages and the correlation of these microbial characteristics with reproductive status.

METHODS

We used a macrogenomic approach to analyze the functional aspects of different microorganisms in samples collected during the pre-estrus, estrus, late estrus, and diestrus stages.

RESULTS

The results revealed the presence of 1293 microbial genera and 3401 microbial species in the uteri of yaks at different reproductive stages. The dominant bacterial species varied across the different periods, with Micrococcus and Proteus being dominant during pre-estrus; Pseudomonas, Clostridium, Flavobacterium, Bacillus, and Staphylococcus during estrus; Acinetobacter, Bacillus and Proteus during late estrus; and Pseudomonas, Escherichia coli, and Proteus during diestrus.

DISCUSSION

The primary functions of these bacteria are enriched in various metabolic pathways, including carbohydrate and amino acid metabolism, intracellular transport and secretion, post-translational protein modification, and drug resistance. These findings suggest that the microbial diversity in the uterus of yaks plays a crucial role in reproductive regulation and can help prevent reproductive tract-related diseases.

DIRECT: Digital Microfluidics for Isolation-Free Shared Library Construction of Single-Cell DNA Methylome and Transcriptome

Simultaneous profiling of DNA methylation and gene expression within single cells is a powerful technology to dissect complex gene regulatory network of cells. However, existing methods are based on picking a single-cell in a tube and split single-cell lysate into two parts for transcriptome and methylome library construction, respectively, which is costly and cumbersome. Here, DIRECT is proposed, a digital microfluidics-based method for high-efficiency single-cell isolation and simultaneous analysis of the methylome and transcriptome in a single library construction. The accuracy of DIRECT is demonstrated in comparison with bulk and single-omics data, and the high CpG site coverage of DIRECT allows for precise analysis of copy number variation information, enabling expansion of single cell analysis from two- to three-omics. By applying DIRECT to monitor the dynamics of mouse embryonic stem cell differentiation, the relationship between DNA methylation and changes in gene expression during differentiation is revealed. DIRECT enables accurate, robust, and reproducible single-cell DNA methylation and gene expression co-analysis in a more cost-effective, simpler library preparation and automated manner, broadening the application scenarios of single-cell multi-omics analysis and revealing a more comprehensive and fine-grained map of cellular regulatory landscapes.

Natural medicinal compounds target signal transduction pathways to overcome ABC drug efflux transporter-mediated multidrug resistance in cancer

ATP-binding cassette (ABC) transporters such as ABCB1, ABCG2, and ABCC1 are the major players in drug efflux-mediated multidrug resistance (MDR), which severely affects the efficacy of chemotherapy. Several synthetic compounds block the drug transport by ABC transporters; however, they exhibit a narrow therapeutic window, and produce side effects in non-target normal tissues. Conversely, the downregulation of the expression of ABC drug transporters seems to be a promising strategy to reverse MDR in cancer cells. Several signaling pathways, such as NF-κB, STAT3, Gli, NICD, YAP/TAZ, and Nrf2 upregulate the expression of ABC drug transporters in drug-resistant cancers. Recently, natural medicinal compounds have gained importance to overcome the ABC drug-efflux pump-mediated MDR in cancer. These compounds target transcription factors and the associated signal transduction pathways, thereby downregulating the expression of ABC transporters in drug-resistant cancer cells. Several potent natural compounds have been identified as lead candidates to synergistically enhance chemotherapeutic efficacy, and a few of them are already in clinical trials. Therefore, modulation of signal transduction pathways using natural medicinal compounds for the reversal of ABC drug transporter-mediated MDR in cancer is a novel approach for improving the efficiency of the existing chemotherapeutics. In this review, we discuss the modulatory role of natural medicinal compounds on cellular signaling pathways that regulate the expression of ABC transporters in drug-resistant cancer cells.

Function, mechanism and drug discovery of ubiquitin and ubiquitin-like modification with multiomics profiling for cancer therapy

Ubiquitin (Ub) and ubiquitin-like (Ubl) pathways are critical post-translational modifications that determine whether functional proteins are degraded or activated/inactivated. To date, >600 associated enzymes have been reported that comprise a hierarchical task network (e.g., E1-E2-E3 cascade enzymatic reaction and deubiquitination) to modulate substrates, including enormous oncoproteins and tumor-suppressive proteins. Several strategies, such as classical biochemical approaches, multiomics, and clinical sample analysis, were combined to elucidate the functional relations between these enzymes and tumors. In this regard, the fundamental advances and follow-on drug discoveries have been crucial in providing vital information concerning contemporary translational efforts to tailor individualized treatment by targeting Ub and Ubl pathways. Correspondingly, emphasizing the current progress of Ub-related pathways as therapeutic targets in cancer is deemed essential. In the present review, we summarize and discuss the functions, clinical significance, and regulatory mechanisms of Ub and Ubl pathways in tumorigenesis as well as the current progress of small-molecular drug discovery. In particular, multiomics analyses were integrated to delineate the complexity of Ub and Ubl modifications for cancer therapy. The present review will provide a focused and up-to-date overview for the researchers to pursue further studies regarding the Ub and Ubl pathways targeted anticancer strategies.

Tumor microenvironment diversity and plasticity in cancer multidrug resistance

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

Development and validation of cuproptosis-related lncRNAs associated with pancreatic cancer immune microenvironment based on single-cell

Background

Cuproptosis, a novel mode of cell death associated with the tricarboxylic acid (TCA) cycle, is relevant to the development of cancer. However, the impact of single-cell-based Cuproptosis-associated lncRNAs on the Tumor immune microenvironment (TIME) of Pancreatic adenocarcinoma (PAAD) and its potential value for individualized immunotherapy has not been clarified.

Methods

14 immune-related CRGs were screened by exploring the interaction between differentially expressed Immune-Related Genes (IRGs) and Cuproptosis-Related Genes (CRGs) in PAAD. Next, the expression amount and expression distribution of CRGs in single-cell samples were analyzed by focusing on 7-CRGs with significant expressions. On the one hand, MAP2K2, SOD1, and VEGFA, which were significantly differentially expressed between PAAD sites and normal tissues adjacent to them, were subjected to immunohistochemical validation and immune landscape analysis. On the other hand, from these 7-CRGs, prognostic signatures of lncRNAs were established by co-expression and LASSO-COX regression analysis, and their prognostic value and immune relevance were assessed. In addition, this study not only validated the hub CRGs and the lncRNAs constituting the signature in a PAAD animal model treated with immunotherapy-based combination therapy using immunohistochemistry and qRT-PCR but also explored the potential value of the combination of targeted, chemotherapy and immunotherapy.

Results

Based on the screening of 7-CRGs significantly expressed in a PAAD single-cell cohort and their co-expressed Cuproptosis-Related lncRNAs (CRIs), this study constructed a prognostic signature of 4-CRIs named CIR-score. A Nomogram integrating the CIR-score and clinical risk factors was constructed on this basis to predict the individualized survival of patients. Moreover, high and low-risk groups classified according to the median of signatures exhibited significant differences in clinical prognosis, immune landscape, bioenrichment, tumor burden, and drug sensitivity. And the immunohistochemical and qRT-PCR results of different mouse PAAD treatment strategies were consistent with the trend of inter-group variability in drug sensitivity of hub CRGs and CIR-score. The combination of immunotherapy, targeted therapy, and chemotherapy exhibited a better tumor suppression effect.

Conclusion

CIR-score, as a Cuproptosis-related TIME-specific prognostic signature based on PAAD single cells, not only predicts the prognosis and immune landscape of PAAD patients but also provides a new strategy for individualized immunotherapy-based combination therapy.

In silico resources help combat cancer drug resistance mediated by target mutations

Drug resistance causes catastrophic cancer treatment failures. Mutations in target proteins with altered drug binding indicate a main mechanism of cancer drug resistance (CDR). Global research has generated considerable CDR-related data and well-established knowledge bases and predictive tools. Unfortunately, these resources are fragmented and underutilized. Here, we examine computational resources for exploring CDR caused by target mutations, analyzing these tools based on their functional characteristics, data capacity, data sources, methodologies and performance. We also discuss their disadvantages and provide examples of how potential inhibitors of CDR have been discovered using these resources. This toolkit is designed to help specialists explore resistance occurrence effectively and to explain resistance prediction to non-specialists easily.

Towards understandings of serine/arginine-rich splicing factors

Serine/arginine-rich splicing factors (SRSFs) refer to twelve RNA-binding proteins which regulate splice site recognition and spliceosome assembly during precursor messenger RNA splicing. SRSFs also participate in other RNA metabolic events, such as transcription, translation and nonsense-mediated decay, during their shuttling between nucleus and cytoplasm, making them indispensable for genome diversity and cellular activity. Of note, aberrant SRSF expression and/or mutations elicit fallacies in gene splicing, leading to the generation of pathogenic gene and protein isoforms, which highlights the therapeutic potential of targeting SRSF to treat diseases. In this review, we updated current understanding of SRSF structures and functions in RNA metabolism. Next, we analyzed SRSF-induced aberrant gene expression and their pathogenic outcomes in cancers and non-tumor diseases. The development of some well-characterized SRSF inhibitors was discussed in detail. We hope this review will contribute to future studies of SRSF functions and drug development targeting SRSFs.