RGDV-modified gemcitabine: a nano-medicine capable of prolonging half-life, overcoming resistance and eliminating bone marrow toxicity of gemcitabine

An overview of phenylsulfonylfuroxan-based nitric oxide donors for cancer treatment

Nitric oxide (NO) is a gaseous molecule integral to numerous physiological processes, including tumor modulation, cardiovascular regulation, and systemic physiological functions. Its dual role in promoting and inhibiting tumor growth makes it a focal point of contemporary oncological research. Phenylsulfonylfuroxan, a classical NO donor, has been shown to significantly elevate NO levels, thereby inducing apoptosis and inhibiting proliferation and metastasis in tumor cells. It enhances the efficacy of chemotherapy, radiotherapy, and immunotherapy, reverses multidrug resistance (MDR), and impedes tumor progression. Notably, phenylsulfonylfuroxan have the ability to trigger ferroptosis in cancer cells by binding covalently to inhibit glutathione peroxidase 4 (GPX4). Recent developments in phenylsulfonylfuroxan-based therapies have positioned them as crucial in the advancement of cancer treatment modalities. This review elucidates the mechanism by which phenylsulfonylfuroxan releases NO and summarizes the significant advancements over the past 16 years in the research and development of phenylsulfonylfuroxan conjugates with various anticancer agents for targeted cancer therapy.

Development and optimization of a high-throughput HPLC-MS/MS method for the simultaneous determination of Cedazuridine, Gemcitabine and its metabolite in mouse plasma

Gemcitabine (GEM) has been extensively applied in treating various solid tumors. Nonetheless, GEM is easily metabolized in vivo by cytidine deaminase (CDA) to inactive 2', 2'-Difluorodeoxyuridine (dFdU) results in a low oral bioavailability, which limit its clinical application. It was found that Cedazuridine (CDZ) could effectively inhibit the deamination of the drug by CDA, and its combination with GEM might affect the oral bioavailability of GEM. To investigate the effect of CDZ on the bioavailability and metabolism of GEM after oral administration, an HPLC-MS/MS method was developed for the simultaneous determination of CDZ, GEM, and its metabolite dFdU in mouse plasma. The separation of CDZ, GEM and dFdU was performed on an acetonitrile and water containing 0.1 % formic acid in isocratic elution on a COSMOSIL® 5C18-PAQ packed column (150 × 4.6 mm, 2.6 µm). The three analytes and the internal standard were determined in a multiple reaction monitoring (MRM) mode under positive ion conditions. The three analytes showed good linearity in the range of 5-10,000 ng/mL, and all quality control samples showed good precision and accuracy. The method was successfully applied to the pharmacokinetic study of GEM with CDZ. The results showed that CDZ significantly improved the oral bioavailability of GEM by reducing the metabolism of CDA to GEM in mice, which will provide a reference for the combined application of GEM and CDZ in clinical therapy.

Identification of Aberrant Expression of Gemcitabine-Targeting Proteins in Drug-Resistant Cells Using an Activity-Based Gemcitabine Probe

Gemcitabine-based monotherapy or combination therapy has become the standard treatment for locally advanced and metastatic pancreatic cancer. However, the emergence of resistance within weeks of treatment severely compromises therapeutic efficacy. The intricate biological process of gemcitabine resistance in pancreatic cancer presents a complex challenge, as the underlying mechanisms remain unclear. Identifying the target protein of gemcitabine is crucial for studying its drug-resistance mechanism. An activity-based probe is a powerful tool for studying drug target proteins, but the current lack of activity-based gemcitabine probes with robust biological activity hinders research on gemcitabine. In this study, we developed three active probes based on gemcitabine, among which Gem-3 demonstrated excellent stability and labeling efficacy. We utilized Gem-3 in conjunction with chemical proteomics to identify intracellular target proteins. We identified 79 proteins that interact with gemcitabine, most of which were previously unknown and represented various functional classes. Additionally, we validated the increased expression of IFIT3 and MARCKS in drug-resistant cells, along with the activation of the NF-κB signaling pathway. These findings substantially contribute to our comprehension of gemcitabine's target proteins and further our understanding of the mechanisms driving gemcitabine resistance in pancreatic cancer cells.

PTX-RPPR, a conjugate of paclitaxel and NRP-1 peptide inhibitor to prevent tumor growth and metastasis

Paclitaxel, a potent anti-tumor drug widely recognized for its therapeutic efficacy, has faced limitations in clinical application due to its poor solubility. The use of Cremophor EL (CrEL) as a cosolvent in paclitaxel injections has been associated with hypersensitivity reactions in some patients. To overcome these challenges, we have developed a novel conjugate by linking a neuropilin-1 targeting peptide, RPPR, to paclitaxel, resulting in PTX-RPPR. This innovative approach has significantly enhanced the solubility of paclitaxel, achieving a 3.8 mg/mL concentration, a remarkable 90-fold increase over the native drug. PTX-RPPR has shown potent anti-tumor activity, inhibiting tumor cell proliferation with an IC50 ranging from 0.26 to 1.64 μM and effectively suppressing migration, invasion, and angiogenesis at a concentration of 75 nM. Notably, in a 4T1 mammary carcinoma model, PTX-RPPR administered at a dose of 0.7 μmol/kg exhibited tumor growth inhibition comparable to that of paclitaxel at a higher dose of 3.5 μmol/kg, with superior efficacy in preventing lung metastasis. Furthermore, PTX-RPPR effectively reduced NRP-1 expression in both tumors and lungs post-treatment. In contrast to paclitaxel formulated with CrEL, PTX-RPPR did not induce IL-6 expression, suggesting a safer profile in terms of immunological response. Characterized by a particle size of 200 nm and a zeta potential of +30 mV, the nano-formulation of PTX-RPPR demonstrated remarkable stability over seven days. This study introduced PTX-RPPR as a promising peptide-drug conjugate that addresses the solubility and hypersensitivity issues associated with paclitaxel, offering a safer therapeutic strategy for cancer treatment.

Sterol-like drugs potentiate statin-triggered prostate cancer cell death by inhibiting SREBP2 nuclear translocation

There is an urgent need to provide immediate and effective options for the treatment of prostate cancer (PCa) to prevent progression to lethal castration-resistant PCa (CRPC). The mevalonate (MVA) pathway is dysregulated in PCa, and statin drugs commonly prescribed for hypercholesterolemia, effectively target this pathway. Statins exhibit anti-PCa activity, however the resulting intracellular depletion of cholesterol triggers a feedback loop that restores MVA pathway activity, thus diminishing statin efficacy and contributing to resistance. To identify drugs that block this feedback response and enhance the pro-apoptotic activity of statins, we performed a high-content image-based screen of a 1508 drug library, enriched for FDA-approved compounds. Two of the validated hits, Galeterone (GAL) and Quinestrol, share the cholesterol-related tetracyclic structure, which is also evident in the FDA-approved CRPC drug Abiraterone (ABI). Molecular modeling revealed that GAL, Quinestrol and ABI not only share structural similarity with 25-hydroxy-cholesterol (25HC) but were also predicted to bind similarly to a known protein-binding site of 25HC. This suggested GAL, Quinestrol and ABI are sterol-mimetics and thereby inhibit the statin-induced feedback response. Cell-based assays demonstrated that these agents inhibit nuclear translocation of sterol-regulatory element binding protein 2 (SREBP2) and the transcription of MVA genes. Sensitivity was independent of androgen status and the Fluva-GAL combination significantly impeded CRPC tumor xenograft growth. By identifying cholesterol-mimetic drugs that inhibit SREBP2 activation upon statin treatment, we provide a potent "one-two punch" against CRPC progression and pave the way for innovative therapeutic strategies to combat additional diseases whose etiology is associated with SREBP2 dysregulation.

A Cathepsin B-Sensitive Gemcitabine Prodrug for Enhanced Pancreatic Cancer Therapy

Although gemcitabine (GEM) is a first-line chemotherapeutic drug in treating pancreatic cancer, the therapeutic efficacy of GEM is relatively poor. One main reason is that GEM can be easily deaminated to inactive 2',2'-difluorodeoxyuridine (dFdU) by cytidine deaminase (CDA). In order to improve the antitumor activity of GEM, a polypeptide modified GEM prodrug RGDGFLG-GEM (GEM-RGD) is designed. Because the amino group of GEM is protected by RGDGFLG peptide sequence, the in vivo stability of GEM-RGD can be significantly improved since the deamination of GEM can be avoided. GEM-RGD shows enhanced uptake by pancreatic cancer cells due to the active targeting RGD group. The cathepsin B-sensitive GFLG sequence endows GEM-RGD with specific release of GEM in pancreatic cancer cells. Compared to free GEM and non-targeted GEM prodrug RDGGFLG-GEM (GEM-RDG), GEM-RGD exhibits enhanced antitumor activity and reduced systemic toxicity. These results implies that GEM-RGD is a promising candidate in treating pancreatic cancer.

Stimuli-responsive drug delivery systems triggered by intracellular or subcellular microenvironments

Drug delivery systems (DDS) triggered by local microenvironment represents the state-of-art of nanomedicine design, where the triggering hallmarks at intracellular and subcellular levels could be employed to exquisitely recognize the diseased sites, reduce side effects, and expand the therapeutic window by precisely tailoring the drug-release kinetics. Though with impressive progress, the DDS design functioning at microcosmic levels is fully challenging and underexploited. Here, we provide an overview describing the recent advances on stimuli-responsive DDSs triggered by intracellular or subcellular microenvironments. Instead of focusing on the targeting strategies as listed in previous reviews, we herein mainly highlight the concept, design, preparation and applications of stimuli-responsive systems in intracellular models. Hopefully, this review could give useful hints in developing nanoplatforms proceeding at a cellular level.

Aptamer–Gemcitabine Conjugates with Enzymatically Cleavable Linker for Targeted Delivery and Intracellular Drug Release in Cancer Cells

Gemcitabine is a chemotherapeutic used clinically to treat a variety of cancers. However, because it lacks tumor cell specificity, gemcitabine may cause off-target cytotoxicity and adversely impact patients. To impart cancer cell specificity to gemcitabine and improve its therapeutic efficacy, we synthesized a unique aptamer–drug conjugate that carries a high gemcitabine payload (three molecules) via a dendrimer structure and enzymatically cleavable linkers for controlled intracellular drug release. First, linker–gemcitabinedendrimer–linker–gemcitabine products were produced, which had significantly lower cytotoxicity than an equimolar amount of free drug. Biochemical analysis revealed that lysosomal cathepsin B protease rapidly cleaved the dendritic linkers and released the conjugated gemcitabine as a free drug. Subsequently, the dendrimer–linker–gemcitabine was coupled with a cell-specific aptamer to form aptamer–gemcitabine conjugates. Functional assays confirmed that, under aptamer guidance, aptamer–gemcitabine conjugates were selectively bound to and then internalized by triple-negative breast cancer cells. Cellular therapy studies indicated that the aptamer–gemcitabine conjugates potentiated cytotoxic activity to targeted cancer cells but did not affect off-target control cells. Our study demonstrates a novel approach to aptamer-mediated targeted drug delivery that combines a high drug payload and an enzymatically controlled drug release switch to achieve higher therapeutic efficacy and fewer off-target effects relative to free-drug chemotherapy.

Trefoil factor 3 promotes pancreatic carcinoma progression via WNT pathway activation mediated by enhanced WNT ligand expression

Pancreatic ductal adenocarcinoma (PDAC) is a major cause of cancer-related mortality with a dismal prognosis that has changed little over the past few decades. Further understanding of the molecular pathology of PDAC progression is urgently required in order to improve the prognosis of patients with PDAC. Herein, it was observed that trefoil factor 3 (TFF3) expression was elevated in PDAC, and was positively correlated with a worse overall patient survival outcome. Forced expression of TFF3 promoted oncogenic functions of PDAC cells in vitro including cell proliferation, survival, foci formation, cancer stem cell-like behavior and invasion, ex vivo colony growth in 3D-Matrigel, and xenograft growth in vivo. Depletion or pharmacological inhibition of TFF3 inhibited these same processes. RNA-Seq analysis and subsequent mechanistic analyses demonstrated that TFF3 increased the expression of various WNT ligands to mediate WNT pathway activation required for TFF3-stimulated PDAC progression. Combined pharmacological inhibition of TFF3 and WNT signaling significantly attenuated PDAC xenograft growth and potentiated the therapeutic efficacy of gemcitabine in both ex vivo and in vivo models. Hence, a mechanistic basis for combined inhibition of pathways enhancing PDAC progression is provided and suggests that inhibition of TFF3 may assist to ameliorate outcomes in PDAC.

Two Possible Strategies for Drug Modification of Gemcitabine and Future Contributions to Personalized Medicine

Drug repurposing is an emerging strategy, which uses already approved drugs for new medical indications. One such drug is gemcitabine, an anticancer drug that only works at high doses since a portion is deactivated in the serum, which causes toxicity. In this review, two methods were discussed that could improve the anticancer effect of gemcitabine. The first is a chemical modification by conjugation with cell-penetrating peptides, namely penetratin, pVEC, and different kinds of CPP6, which mostly all showed an increased anticancer effect. The other method is combining gemcitabine with repurposed drugs, namely itraconazole, which also showed great cancer cell inhibition growth. Besides these two strategies, physiologically based pharmacokinetic models (PBPK models) are also the key for predicting drug distribution based on physiological data, which is very important for personalized medicine, so that the correct drug and dosage regimen can be administered according to each patient’s physiology. Taking all of this into consideration, it is believed that gemcitabine can be repurposed to have better anticancer effects.

Gemcitabine Nanoparticles Improve the Activity of Ovarian Cancer Cells by Inhibiting CA-125 and Apoptosis-Related Proteins

In recent years, the risk of ovarian cancer (OC) has become increasingly prevalent. Gemcitabine (GE) provides excellent inhibitory action on some solid tumors, but how it affects OC remains elusive. In the present research, we prepared GE nanoparticles (GEN) and analyzed OC cell viability under its intervention, hoping to conceive novel ideas for future clinical treatment of OC. Through experiments, we observed that the encapsulation efficiency and drug loading of GEN were observably higher than those of GE alone, and the release rate presented a stable slow release state. Under GEN intervention, the viability of OC cells was decreased, the apoptosis rate was elevated, and the apoptosis-related proteins were activated, while CA-125 was suppressed. Therefore, we can see that GEN exert favorable inhibitory action on OC cell viability, whose mechanism may be achieved through activating apoptosis-related proteins and inhibiting CA-125, which may be a new scheme for OC treatment in the future.

Gemcitabine Peptide-Based Conjugates and Their Application in Targeted Tumor Therapy

A major obstacle in tumor treatment is associated with the poor penetration of a therapeutic agent into the tumor tissue and with their adverse influence on healthy cells, which limits the dose of drug that can be safely administered to cancer patients. Gemcitabine is an anticancer drug used to treat a wide range of solid tumors and is a first-line treatment for pancreatic cancer. The effect of gemcitabine is significantly weakened by its rapid plasma degradation. In addition, the systemic toxicity and drug resistance significantly reduce its chemotherapeutic efficacy. Up to now, many approaches have been made to improve the therapeutic index of gemcitabine. One of the recently developed approaches to improve conventional chemotherapy is based on the direct targeting of chemotherapeutics to cancer cells using the drug-peptide conjugates. In this work, we summarize recently published gemcitabine peptide-based conjugates and their efficacy in anticancer therapy.

Exploring the action of RGDV-gemcitabine on tumor metastasis, tumor growth and possible action pathway

The coupling of Arg-Gly-Asp-Val (RGDV) and gemcitabine led to a hypothesis that the conjugate (RGDV-gemcitabine) could inhibit tumor metastasis. To confirm this hypothesis the activities of RGDV-gemcitabine inhibiting tumor metastasis in vitro and in vivo were presented for the first time. AFM (atomic force microscopy) imaged that RGDV-gemcitabine was able to adhere onto the surface of serum-starved A549 cells, to block the extending of the pseudopodia. Thereby RGDV-gemcitabine was able to inhibit the invasion, migration and adhesion of serum-starved A549 cells in vitro. On C57BL/6 mouse model RGDV-gemcitabine dose dependently inhibited the metastasis of planted tumor towards the lung and the minimal dose was 0.084 µmol/kg/3 days. The decrease of serum TNF-α (tumor necrosis factor), IL-8 (interleukin-8), MMP-2 (matrix metalloprotein-2) and MMP-9 (matrix metalloprotein-9) of the treated C57BL/6 mice was correlated with the action pathway of RGDV-gemcitabine inhibiting the metastasis of the planted tumor towards lung.

Development of 13-Cys-BBR as an Agent Having Dual Action of Anti-Thrombosis and Anti-Inflammation

Background

There is a correlation between tumor and inflammation. The activity of 13-[CH₂CO-Cys(Bzl)-OBzl]-berberine (13-Cys-BBR) slowing tumor growth is higher than that of BBR. Whether the anti-inflammation activity of 13-Cys-BBR is higher than that of BBR remains unknown. There is a correlation between thrombosis and inflammation. Whether 13-Cys-BBR is an inhibitor of thrombosis remains unknown.

Purpose

The object of this investigation is to compare the activities of 13-Cys-BBR inhibiting thrombosis and inflammation to those of BBR.

Methods

In vivo anti-thrombosis assay was performed on rat model of arterial and venous thrombosis. In vivo anti-inflammation assay was performed on mouse model of xylene induced ear edema.

Results

At oral dose of 66.7 nmol/kg, 13-Cys-BBR, but not BBR, inhibited the rats to form both venous thrombus and arterial thrombus. At oral dose of 2 μmol/kg, 13-Cys-BBR, but not BBR, inhibited the ears of the mice to occur edema.

Conclusion

The anti-venous thrombosis activity, anti-arterial thrombosis activity and anti-inflammation activity of 13-Cys-BBR were significantly higher than those of BBR. 13-Cys-BBR is a promising preclinical candidate.