2D-CuPd nanozyme overcome tamoxifen resistance in breast cancer by regulating the PI3K/AKT/mTOR pathway

Inhibitors of the mTOR signaling pathway can play an important role in breast cancer immunopathogenesis

This study explores the critical role of inhibitors targeting the mammalian target of rapamycin (mTOR) signaling pathway in breast cancer research and treatment. The mTOR pathway, a central regulator of cellular processes, has been identified as a crucial factor in the development and progression of breast cancer. The essay explains the complex molecular mechanisms through which mTOR inhibitors, such as rapamycin and its analogs, exert their anticancer effects. These inhibitors can stop cell growth, proliferation, and survival in breast cancer cells by blocking critical signaling pathways within the mTOR pathway. Furthermore, the essay discusses the implications of using mTOR inhibitors as a comprehensive therapeutic strategy. It emphasizes the potential benefits of combining mTOR inhibitors with other treatment approaches to enhance the effectiveness of breast cancer treatment. The evolving landscape of breast cancer research underscores the significance of mTOR as a therapeutic target and highlights ongoing efforts to improve and optimize mTOR inhibitors for clinical use. In conclusion, the essay asserts that inhibitors of the mTOR signaling pathway offer a promising approach in the fight against breast cancer. These inhibitors provide a focused and effective intervention targeting specific dysregulations within the mTOR pathway. As research advances, the integration of mTOR inhibitors into customized combination therapies holds excellent potential for shaping a more effective and personalized approach to breast cancer treatment, ultimately leading to improved outcomes for individuals affected by this complex and diverse disease.

Nano-drug delivery system for the treatment of multidrug-resistant breast cancer: Current status and future perspectives

Breast cancer (BC) is one of the most frequently diagnosed cancers in women. Chemotherapy continues to be the treatment of choice for clinically combating it. Nevertheless, the chemotherapy process is frequently hindered by multidrug resistance, thereby impacting the effectiveness of the treatment. Multidrug resistance (MDR) refers to the phenomenon in which malignant tumour cells develop resistance to anticancer drugs after one single exposure. It can occur with a broad range of chemotherapeutic drugs with distinct chemical structures and mechanisms of action, and it is one of the major causes of treatment failure and disease relapse. Research has long been focused on overcoming MDR by using multiple drug combinations, but this approach is often associated with serious side effects. Therefore, there is a pressing need for in-depth research into the mechanisms of MDR, as well as the development of new drugs to reverse MDR and improve the efficacy of breast cancer chemotherapy. This article reviews the mechanisms of multidrug resistance and explores the application of nano-drug delivery system (NDDS) to overcome MDR in breast cancer. The aim is to offer a valuable reference for further research endeavours.

Targeting PI3K/AKT/mTOR signaling to overcome drug resistance in cancer

This review comprehensively explores the challenge of drug resistance in cancer by focusing on the pivotal PI3K/AKT/mTOR pathway, elucidating its role in oncogenesis and resistance mechanisms across various cancer types. It meticulously examines the diverse mechanisms underlying resistance, including genetic mutations, feedback loops, and microenvironmental factors, while also discussing the associated resistance patterns. Evaluating current therapeutic strategies targeting this pathway, the article highlights the hurdles encountered in drug development and clinical trials. Innovative approaches to overcome resistance, such as combination therapies and precision medicine, are critically analyzed, alongside discussions on emerging therapies like immunotherapy and molecularly targeted agents. Overall, this comprehensive review not only sheds light on the complexities of resistance in cancer but also provides a roadmap for advancing cancer treatment.

The FOXO1/G6PC axis promotes gastric cancer progression and mediates 5-fluorouracil resistance by targeting the PI3K/AKT/mTOR signaling pathway

Gastric cancer (GC) is a prevalent malignancy of the digestive system. Distant metastasis and chemotherapy resistance are the crucial obstacles to prognosis in GC. Recent research has discovered that the glucose-6-phosphatase catalytic subunit (G6PC) plays an important role in tumor malignant development. However, little evidence has highlighted its role in GC. Herein, through a comprehensive analysis including profiling of tissue samples and functional validation in vivo and in vitro, we identify G6PC as a crucial factor in GC tumorigenesis. Importantly, we found that the FOXO1/G6PC axis could accelerate GC cell proliferation, metastasis, and 5-Fluorouracil (5-FU) resistance by targeting the PI3K/AKT/mTOR signaling pathway, implicating that as a prospective therapeutic approach in GC.

Synergistic action of cavity and catalytic sites in etched Pd-Cu2O octahedra to augment the peroxidase-like activity of Cu2O nanoparticles for the colorimetric detection of isoniazid and ascorbic acid

Despite the widespread use of nanozyme-based colorimetric assays in biosensing, challenges such as limited catalytic efficiency, inadequate sensitivity to analytes, and insufficient understanding of the structure-activity relationship still persist. Overcoming these hurdles by enhancing the inherent enzyme-like performance of nanozymes using the unique attributes of nanomaterials is still a significant obstacle. Here, we designed and constructed Pd-Cu2O nanocages (Pd-Cu2O NCs) by selectively etching the vertices of the copper octahedra to enhance the peroxidase-like (POD-like) activity of Cu2O nanoparticles. The improved catalytic activity of Pd-Cu2O NCs was attributed to their high specific surface area and abundant catalytic sites. Mechanistic studies revealed that reactive oxygen species (ROS) intermediates (•OH) were generated through the decomposition of H2O2, resulting in POD-like activity of the Pd-Cu2O NCs. The designed Pd-Cu2O NCs can oxidize 3,3',5,5'-tetramethylbenzidine (TMB) in the presence of H2O2, producing a blue oxidation product (oxTMB). The oxidation reaction was inhibited and led to a significant bleaching of the blue color in the presence of reducing substances isoniazid (INH) and ascorbic acid (AA). Based on these principles, we developed a colorimetric sensing platform for the detection of INH and AA, exhibiting good sensitivity and stability. This work provided a straightforward approach to the structural engineering of nanomaterials and the enhancement of enzyme-mimicking properties.

Mitochondrial Disruption Nanosystem Simultaneously Depressed Programmed Death Ligand-1 and Transforming Growth Factor-β to Overcome Photodynamic Immunotherapy Resistance

Currently, limited photosensitizers possess the capacity to reverse tumor hypoxia and reduce programmed death ligand-1 (PD-L1) and transforming growth factor-β (TGF-β) expression simultaneously, hindering the perfect photodynamic therapy (PDT) effect due to acquired immune resistance and the tumor hypoxic microenvironment. To tackle these challenges, in this research, we demonstrated that mitochondrial energy metabolism depression can be utilized as an innovative and efficient approach for reducing the expression of PD-L1 and TGF-β simultaneously, which may offer a design strategy for a more ideal PDT nanosystem. Through proteomic analysis of 5637 cells, we revealed that tamoxifen (TMX) can incredibly regulate PD-L1 expression in tumor cells. Then, to selectively deliver clinically used mitochondrial energy metabolism depressant TMX to solid tumors as well as design an ideal PDT nanosystem, we synthesized MHI-TMX@ALB by combining a mitochondria-targeted heptamethine cyanine PDT-dye MHI with TMX through self-assembly with albumin (ALB). Interestingly enough, the MHI-TMX@ALB nanoparticle demonstrated effective reversion of tumor hypoxia and inhibition of PD-L1 protein expression at a lower dosage (7.5 times to TMX), which then enhanced the efficacy of photodynamic immunotherapy via enhancing T-cell infiltration. Apart from this, by leveraging the heptamethine dye's targeting capacity toward tumors and TMX's role in suppressing TGF-β, MHI-TMX@ALB also more effectively mitigated 4T1 tumor lung metastasis development. All in all, the MHI-TMX@ALB nanoparticle could be used as a multifunctional economical PD-L1 and TGF-β codepression immune-regulating strategy, broadening the potential clinical applications for a more ideal PDT nanosystem.

Mineral Phase Reconfiguration Enables the High Enzyme-like Activity of Vermiculite for Antibacterial Application

Phyllosilicates-based nanomaterials, particularly iron-rich vermiculite (VMT), have wide applications in biomedicine. However, the lack of effective methods to activate the functional layer covered by the external inert layer limits their future applications. Herein, we report a mineral phase reconfiguration strategy to prepare novel nanozymes by a molten salt method. The peroxidase-like activity of the VMT reconfiguration nanozyme is 10 times that of VMT, due to the electronic structure change of iron in VMT. Density-functional theory calculations confirmed that the upward shifted d-band center of the VMT reconfiguration nanozyme promoted the adsorption of H2O2 on the active iron sites and significantly elongated the O-O bond lengths. The reconfiguration nanozyme exhibited nearly 100% antibacterial activity toward Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus), much higher than that of VMT (E. coli 10%, S. aureus 21%). This work provides new insights for the rational design of efficient bioactive phyllosilicates-based nanozyme.

Enzyme-Responsive Branched Glycopolymer-Based Nanoassembly for Co-Delivery of Paclitaxel and Akt Inhibitor toward Synergistic Therapy of Gastric Cancer

Combined chemotherapy and targeted therapy holds immense potential in the management of advanced gastric cancer (GC). GC tissues exhibit an elevated expression level of protein kinase B (AKT), which contributes to disease progression and poor chemotherapeutic responsiveness. Inhibition of AKT expression through an AKT inhibitor, capivasertib (CAP), to enhance cytotoxicity of paclitaxel (PTX) toward GC cells is demonstrated in this study. A cathepsin B-responsive polymeric nanoparticle prodrug system is employed for co-delivery of PTX and CAP, resulting in a polymeric nano-drug BPGP@CAP. The release of PTX and CAP is triggered in an environment with overexpressed cathepsin B upon lysosomal uptake of BPGP@CAP. A synergistic therapeutic effect of PTX and CAP on killing GC cells is confirmed by in vitro and in vivo experiments. Mechanistic investigations suggested that CAP may inhibit AKT expression, leading to suppression of the phosphoinositide 3-kinase (PI3K)/AKT signaling pathway. Encouragingly, CAP can synergize with PTX to exert potent antitumor effects against GC after they are co-delivered via a polymeric drug delivery system, and this delivery system helped reduce their toxic side effects, which provides an effective therapeutic strategy for treating GC.

Robinin inhibits pancreatic cancer cell proliferation, EMT and inflammation via regulating TLR2-PI3k-AKT signaling pathway

PURPOSE

To investigate the anti-tumor effect of Robinin (Toll-like receptor 2 inhibitor) in pancreatic cancer cells via regulating tumor microenvironment.

METHODS

The effects of Robinin on cell proliferation or migration in Mia-PACA2 and PANC-1 were determined, using CCK8 or wound healing assay, respectively. The typical markers of EMT (αSMA and snail) and the inflammation markers (IL-6 and TNF-α) were all detected by western blot. CU-T12-9 (TLR2 agonist) was used to rescue Robinin's effect. PI3k-p85α and Phosphorylated-AKT (p-AKT) were evaluated, compared to the β-actin and AKT, using western blot.

RESULTS

Robinin significantly inhibited cell proliferation and migration in Mia-PACA2 and PANC-1, compared to HPNE (**P < 0.01). Robinin also attenuated the expression of α-SMA and snail in Mia-PACA2, and PANC-1 (**P < 0.01). Besides, it was found that expression of IL-6 and TNF-α were diminished in presence of Robinin in Mia-PACA2, and PANC-1 (**P < 0.01). Western blot confirmed that Robinin could target on TLR2, and further downregulated PI3k-AKT signaling pathway to exert biological function.

CONCLUSIONS

Robinin exerts anti-tumor effect perhaps via downregulating inflammation and EMT in pancreatic cancer cell through inhibiting TLR2-PI3k-AKT signaling pathway. Robinin may be a novel agent in adjuvant therapy of pancreatic cancer.

Overview of nanozymes with phosphatase-like activity

Nanomaterials with intrinsic enzyme activity, referred to as nanozymes, have attracted substantial attention in recent years. Among them, phosphatase-mimicking nanozymes have become an increasingly important focus for future research, considering that phosphatase is not only one of key enzymes for phosphorous metabolism, which is essential for many biological processes (e.g., cellular regulation and signaling), but also one of extensively used biocatalytic labels in the enzyme-linked assays as well as a powerful tool enzyme in molecular biology laboratories. Nevertheless, compared with extensive oxidoreductase-mimicking nanozymes, there are a very limited number of nanozymes with phosphatase-like activity have been explored at present. The increasing demand of complex and individualized phosphatase-involved catalytic behaviors is pushing the development of more advanced phosphatase-mimicking nanozymes. Thus, we present an overview on recently reported phosphatase-like nanozymes, providing guidelines and new insights for designing more advanced phosphatase-mimicking nanozyme with superior properties.

A tumor cell exosome-mimicking multifunctional nanozyme for targeted breast cancer radiotherapy

Radiotherapy (RT) has been extensively used for the treatment of breast cancer. However, the efficacy of RT is reduced by the high content of reducing species within cells (such as glutathione (GSH)). In addition, high-dose radiotherapy is often accompanied by serious side effects. In an attempt to resolve these issues, a tumor cell exosome-mimicking multifunctional nanozyme system (CuPy-Au@EM) was developed as a radiosensitizer, which consists of an internal AuNP-embedded CuPy nanozyme core and an external tumor cell exosome membrane. The exosome membrane protein on the surface of CuPy-Au@EM leads to the accurate localization of nano-materials in the tumor site; simultaneously, the level of H2O2 will be enhanced because of the GOx-like activity of AuNPs. Then CuPy-Au@EM would continue to trigger a rapid decline in cellular GSH content and the production of a large number of hydroxyl radicals (˙OH) through its glutathione peroxidase (GPx) and peroxidase (POD) activities allows for the extension of the radiotherapeutic cascade. Studies conducted in vivo and in vitro demonstrated that the combination of CuPy-Au@EM and moderate dose RT (4 Gy) can significantly reduce tumor proliferation. These findings indicated that CuPy-Au@EM nanospheres could be plausibly developed into promising radio-sensitizers on tumors.