Esomeprazole overcomes paclitaxel-resistance and enhances anticancer effects of paclitaxel by inducing autophagy in A549/Taxol cells

In human CD4+ T-Cells, omeprazole suppresses proliferation, downregulates V-ATPase, and promotes differentiation toward an autoimmunity-favoring phenotype

BACKGROUND

Proton pump inhibitors (PPIs) represent a commonly prescribed class of medications. Triggered by findings indicating a correlation between PPI usage and susceptibility to infectious or autoimmune diseases, we studied the impact of a pharmacological concentration of omeprazole on human CD4+ T-cells.

METHODS

In mixed lymphocyte reactions (MLRs), we analyzed the proliferation index and measured the concentration of key cytokines representative of distinct CD4+ T-cell subsets. In CD4+ T-cells isolated from the MLRs, we evaluated proliferation markers and pathways, the expression of signature transcription factors of CD4+ T-cell subsets, vacuolar H+- ATPase (V-ATPase) levels, and the activation status of AMP-activated kinase (AMPK) and mammalian target of rapamycin complex-1 (mTORC1).

RESULTS

Omeprazole reduced proliferation index in MLRs, and in isolated CD4+ T-cells, it downregulated the proliferation marker Ki-67, possibly mediated by the p53- p21 pathway. Analysis of cytokines and signature transcription factors of CD4+ T-cell subsets indicated that omeprazole decreased T helper 1 (Th1) differentiation, had negligible impact on Th2 differentiation, increased Th17 differentiation, and reduced regulatory T-cell (Treg) differentiation. Omeprazole also decreased V-ATPase, a known target of PPIs and a site for AMPK and mTORC1 activation. Consequently, this led to diminished activation of these kinases, potentially elucidating the mechanism by which omeprazole influences CD4+ T-cell differentiation.

CONCLUSION

Omeprazole downregulates V-ATPase and inhibits activation of AMPK and mTORC1. As a result, omeprazole suppresses CD4+ T-cell clonal expansion, potentially contributing to the observed association between PPIs and susceptibility to infections. Additionally, it modulates CD4+ T-cell differentiation in a manner that favors autoimmunity.

Itraconazole Reversing Acquired Resistance to Osimertinib in NSCLC by Inhibiting the SHH/DUSP13B/p-STAT3 Axis

There is an urgent necessity to devise efficient tactics to tackle the inevitable development of resistance to osimertinib, which is a third-generation epidermal growth factor receptor (EGFR) inhibitor used in treating EGFR-mutant nonsmall cell lung cancer (NSCLC). This study demonstrates that combining itraconazole with osimertinib synergistically reduces the proliferation and migration, enhances the apoptosis of osimertinib-resistant cells, and effectively inhibits the growth of osimertinib-resistant tumors. Mechanistically, itraconazole combined with osimertinib promotes the proteasomal degradation of sonic hedgehog (SHH), resulting in inactivation of the SHH/Dual-specificity phosphatase 13B (DUSP13B)/p-STAT3 and Hedgehog pathways, suppressing Myc proto-oncogene protein (c-Myc). Additionally, DUSP13B interacts with signal transducer and activator of transcription 3 (STAT3) and modulates its phosphorylation. Interestingly, it is observed that SHH overexpression partially rescues the synergistic effects of this combination treatment strategy through the SHH/DUSP13B/p-STAT3 signaling axis. Moreover, it is found that SHH, (GLI1), p-STAT3, and DUSP13B play significant predictive roles in osimertinib resistance. In lung adenocarcinoma, p-STAT3 is positively correlated with SHH but negatively correlated with DUSP13B. Together, these results highlight the crucial role of itraconazole in reversing the acquired resistance to osimertinib and provide a scientific rationale for the therapeutic strategy of combining osimertinib with itraconazole.

Programmable Nanomodulators for Precision Therapy, Engineering Tumor Metabolism to Enhance Therapeutic Efficacy

Tumor metabolism is crucial in the continuous advancement and complex growth of cancer. The emerging field of nanotechnology has made significant strides in enhancing the understanding of the complex metabolic intricacies inherent to tumors, offering potential avenues for their strategic manipulation to achieve therapeutic goals. This comprehensive review delves into the interplay between tumor metabolism and various facets of cancer, encompassing its origins, progression, and the formidable challenges posed by metastasis. Simultaneously, it underscores the classification of programmable nanomodulators and their transformative impact on enhancing cancer treatment, particularly when integrated with modalities such as chemotherapy, radiotherapy, and immunotherapy. This review also encapsulates the mechanisms by which nanomodulators modulate tumor metabolism, including the delivery of metabolic inhibitors, regulation of oxidative stress, pH value modulation, nanoenzyme catalysis, nutrient deprivation, and RNA interference technology, among others. Additionally, the review delves into the prospects and challenges of nanomodulators in clinical applications. Finally, the innovative concept of using nanomodulators to reprogram metabolic pathways is introduced, aiming to transform cancer cells back into normal cells. This review underscores the profound impact that tailored nanomodulators can have on tumor metabolic, charting a path toward pioneering precision therapies for cancer.

The Interplay between Autophagy and Mitochondria in Cancer

Besides producing cellular energy, mitochondria are crucial in controlling oxidative stress and modulating cellular metabolism, particularly under stressful conditions. A key aspect of this regulatory role involves the recycling process of autophagy, which helps to sustain energy homeostasis. Autophagy, a lysosome-dependent degradation pathway, plays a fundamental role in maintaining cellular homeostasis by degrading damaged organelles and misfolded proteins. In the context of tumor formation, autophagy significantly influences cancer metabolism and chemotherapy resistance, contributing to both tumor suppression and surveillance. This review focuses on the relationship between mitochondria and autophagy, specifically in the context of cancer progression. Investigating the interaction between autophagy and mitochondria reveals new possibilities for cancer treatments and may result in the development of more effective therapies targeting mitochondria, which could have significant implications for cancer treatment. Additionally, this review highlights the increasing understanding of autophagy's role in tumor development, with a focus on modulating mitochondrial function and autophagy in both pre-clinical and clinical cancer research. It also explores the potential for developing more-targeted and personalized therapies by investigating autophagy-related biomarkers.

Synergistic effects of epoxyazadiradione (EAD) and paclitaxel against triple-negative breast cancer cells

BACKGROUND

Triple-negative breast cancer (TNBC) is the most aggressive and chemo-resistant form of breast cancer subtype, and chemotherapy is a vital treatment option for that. Paclitaxel is an effective chemo drug for TNBC. However, in clinical settings, paclitaxel has adverse side effects. The synergistic combination is the most promising method for overcoming undesirable toxicity and achieving a beneficial therapeutic outcome. Previous reports, including our study, showed certain anticancer potential of epoxyazadiradione (EAD), the neem limonoid, in different types of cancer cells, including TNBC.

OBJECTIVE

This study was designed to investigate the possible synergistic effects of EAD and paclitaxel against TNBC cells.

METHODS

We examined the effects of EAD and paclitaxel alone and in combination in MDA-MB 231 cells, and the percentage cytotoxicity was used to calculate synergism. Characteristic apoptotic changes were observed by visualizing cellular morphology, nuclear fragmentation and membrane integrity. We further estimated anti-migratory potential of experimental compounds by wound healing assay. The reduction in inflammation during combinatorial treatment was evaluated by observing NF-κB translocation.

RESULTS

The combined treatment with EAD (5 μM) and paclitaxel (5 nM), which were used at doses lower than their individual IC50 concentrations, showed a synergistic effect in MDA-MB-231 cells. This combination effectively induced apoptosis and antimigration and reduced the inflammatory reactions induced by the higher dose of paclitaxel.

CONCLUSION

To conclude, EAD could be the drug of choice for combined treatment with paclitaxel in a chemotherapy regimen.

Dissecting the multifaceted roles of autophagy in cancer initiation, growth, and metastasis: from molecular mechanisms to therapeutic applications

Autophagy is a cytoplasmic defense mechanism that cells use to break and reprocess their intracellular components. This utilization of autophagy is regarded as a savior in nutrient-deficient and other stressful conditions. Hence, autophagy keeps contact with and responds to miscellaneous cellular tensions and diverse pathways of signal transductions, such as growth signaling and cellular death. Importantly, autophagy is regarded as an effective tumor suppressor because regular autophagic breakdown is essential for cellular maintenance and minimizing cellular damage. However, paradoxically, autophagy has also been observed to promote the events of malignancies. This review discussed the dual role of autophagy in cancer, emphasizing its influence on tumor survival and progression. Possessing such a dual contribution to the malignant establishment, the prevention of autophagy can potentially advocate for the advancement of malignant transformation. In contrast, for the context of the instituted tumor, the agents of preventing autophagy potently inhibit the advancement of the tumor. Key regulators, including calpain 1, mTORC1, and AMPK, modulate autophagy in response to nutritional conditions and stress. Oncogenic mutations like RAS and B-RAF underscore autophagy's pivotal role in cancer development. The review also delves into autophagy's context-dependent roles in tumorigenesis, metastasis, and the tumor microenvironment (TME). It also discusses the therapeutic effectiveness of autophagy for several cancers. The recent implication of autophagy in the control of both innate and antibody-mediated immune systems made it a center of attention to evaluating its role concerning tumor antigens and treatments of cancer.

Autophagy and cancer drug resistance in dialogue: Pre-clinical and clinical evidence

The emergence of drug resistance is a major challenge for oncologists. Resistance can be categorized as acquired or intrinsic; the alteration of several biological mechanisms contributes to both intrinsic and acquired resistance. Macroautophagy/autophagy is the primary process in eukaryotes for the degradation of macromolecules and organelles. This process is critical in maintaining cellular homeostasis. Given its function as either a pro-survival or a pro-death phenomenon, autophagy has a complex physio-pathological role. In some circumstances, autophagy can confer chemoresistance and promote cell survival, whereas in others it can promote chemosensitivity and contribute to cell death. The role of autophagy in the modulation of cancer drug resistance reflects its impact on apoptosis and metastasis. The regulation of autophagy in cancer is mediated by various factors including AMP-activated protein kinase (AMPK), MAPK, phosphoinositide 3-kinase (PI3K)-AKT, BECN1 and ATG proteins. Non-coding RNAs are among the main regulators of autophagy, e.g., via the modulation of chemoresistance pathways. Due to the significant contribution of autophagy in cancer drug resistance, small molecule modulators and natural compounds targeting autophagy have been introduced to alter the response of cancer cells to chemotherapy. Furthermore, nanotherapeutic approaches based on autophagy regulation have been introduced in pre-clinical cancer therapy. In this review we consider the potential for using autophagy regulators for the clinical treatment of malignancies.

Isoliensinine augments the therapeutic potential of paclitaxel in multidrug-resistant colon cancer stem cells and induced mitochondria-mediated cell death

Previously we have reported the isoliensinine (ISO) potentates the therapeutic potential of cisplatin in cisplatin resistant colorectal cancer stem cells. The present study evaluates the chemo-sensitizing potential of the combinatorial regimen of ISO and Paclitaxcel (PTX) on multidrug-resistant (MDR)-HCT-15 cells to reduce the dose requirement of both ISO and PTX. The results of the present study suggest that treatment with the combinatorial regimen of ISO and PTX enhanced the cytotoxic effect with resultant increase in apoptosis in MDR-HCT-15 cells as evident from the altered cellular morphology, G2/M cell cycle arrest, propidium iodide uptake, Annexin V, increased intracellular Ca2+ accumulation, decreased mitochondrial membrane potential, diminished ATP production, PARP-1 cleavage, altered expression of ERK1/2, and apoptotic proteins. Treatment with combinatorial regimen of ISO and PTX also modulated the expression of the transcription factors SOX2, OCT4 which determine the stemness of cancer cells. Thus, results of the present study suggest that ISO and PTX combination regimen induces apoptosis in MDR-HCT-15 in a synergistic manner.

Esomeprazole Alleviates Cisplatin Resistance by Inhibiting the AKT/mTOR Pathway in Ovarian Cancer Cells

Purpose

Ovarian cancer is the most lethal malignancy in gynecology. Due to limited treatment strategies and platinum resistance, newer drugs and therapeutic options are needed. Esomeprazole (ESO) has been reported to have multiple anticancer activities in preclinical and clinical research. Therefore, this study aimed to explore the anticancer effects of esomeprazole on ovarian cancer and its underlying molecular mechanisms.

Methods

CCK-8 and 5-ethynyl-2'-deoxyuridine (EdU) assays were used to detect cell viability and proliferation. The Transwell assay was used to evaluate cell migration and invasion capacity. Flow cytometry was used to detect cell apoptosis. Western blotting and immunofluorescence were used to detect protein expression.

Results

ESO effectively inhibited the cell viability, proliferation, invasion, migration, and induced apoptosis of ovarian cancer cells in a concentration-dependent manner. Treatment with ESO decreased the expression of c-MYC, SKP2, E2F1, N-cadherin, vimentin, and matrix metalloproteinase 2 (MMP2), while it increased E-cadherin, caspase3, p53, BAX, and cleaved poly (ADP-ribose) polymerase (PARP) expression, and downregulated the PI3K/AKT/mTOR signaling pathway. Furthermore, ESO combined with cisplatin showed synergistic effects in inhibiting proliferation, invasion, and migration of cisplatin-resistant ovarian cancer cells. The mechanism may be related to the increased inhibition of c-MYC, epithelial-mesenchymal transition (EMT), and the AKT/mTOR signaling pathway and enhanced the upregulation of the pro-apoptotic protein BAX and cleaved PARP levels. Moreover, ESO combined with cisplatin synergistically upregulated the expression of the DNA damage marker γH2A.X.

Conclusion

ESO exerts multiple anticancer activities and has a synergistic effect in combination with cisplatin on cisplatin-resistant ovarian cancer cells. This study provides a promising strategy to improve chemosensitivity and overcome resistance to cisplatin in ovarian cancer.

A Novel Paclitaxel Derivative for Triple-Negative Breast Cancer Chemotherapy

Paclitaxel-triethylenetetramine hexaacetic acid conjugate (PTX-TTHA), a novel semi-synthetic taxane, is designed to improve the water solubility and cosolvent toxicity of paclitaxel in several aminopolycarboxylic acid groups. In this study, the in vitro and in vivo antitumor effects and mechanisms of PTX-TTHA against triple-negative breast cancer (TNBC) and its intravenous toxicity were evaluated. Results showed the water solubility of PTX-TTHA was greater than 5 mg/mL, which was about 7140-fold higher than that of paclitaxel (<0.7 µg/mL). PTX-TTHA (10-10⁵ nmol/L) could significantly inhibit breast cancer proliferation and induce apoptosis by stabilizing microtubules and arresting the cell cycle in the G2/M phase in vitro, with its therapeutic effect and mechanism similar to paclitaxel. However, when the MDA-MB-231 cell-derived xenograft (CDX) tumor model received PTX-TTHA (13.73 mg/kg) treatment once every 3 days for 21 days, the tumor inhibition rate was up to 77.32%. Furthermore, PTX-TTHA could inhibit tumor proliferation by downregulating Ki-67, and induce apoptosis by increasing pro-apoptotic proteins (Bax, cleaved caspase-3) and TdT-mediated dUTP nick end labeling (TUNEL) positive apoptotic cells, and reducing anti-apoptotic protein (Bcl-2). Moreover, PTX-TTHA demonstrated no sign of acute toxicity on vital organs, hematological, and biochemical parameters at the limit dose (138.6 mg/kg, i.v.). Our study indicated that PTX-TTHA showed better water solubility than paclitaxel, as well as comparable in vitro and in vivo antitumor activity in TNBC models. In addition, the antitumor mechanism of PTX-TTHA was related to microtubule regulation and apoptosis signaling pathway activation.

Nanocarriers overcoming biological barriers induced by multidrug resistance of chemotherapeutics in 2D and 3D cancer models

Multidrug resistance (MDR) is currently a big challenge in cancer therapy and limits its success in several patients. Tumors use the MDR mechanisms to colonize the host and reduce the efficacy of chemotherapeutics that are injected as single agents or combinations. MDR mechanisms are responsible for inactivation of drugs and formbiological barriers in cancer like the drug efflux pumps, aberrant extracellular matrix, hypoxic areas, altered cell death mechanisms, etc. Nanocarriers have some potential to overcome these barriers and improve the efficacy of chemotherapeutics. In fact, they are versatile and can deliver natural and synthetic biomolecules, as well as RNAi/DNAi, thus providing a controlled release of drugs and a synergistic effect in tumor tissues. Biocompatible and safe multifunctional biopolymers, with or without specific targeting molecules, modify the surface and interface properties of nanocarriers. These modifications affect the interaction of nanocarriers with cellular models as well as the selection of suitable models for in vitro experiments. MDR cancer cells, and particularly their 2D and 3D models, in combination with anatomical and physiological structures of tumor tissues, can boost the design and preparation of nanomedicines for anticancer therapy. 2D and 3D cancer cell cultures are suitable models to study the interaction, internalization, and efficacy of nanocarriers, the mechanisms of MDR in cancer cells and tissues, and they are used to tailor a personalized medicine and improve the efficacy of anticancer treatment in patients. The description of molecular mechanisms and physio-pathological pathways of these models further allow the design of nanomedicine that can efficiently overcome biological barriers involved in MDR and test the activity of nanocarriers in 2D and 3D models of MDR cancer cells.

Autophagy in cancer resistance to paclitaxel: Development of combination strategies

Paclitaxel, a compound naturally occurring in yew, is a commonly used drug for the treatment of different types of cancer. Unfortunately, frequent cancer cell resistance significantly decreases its anticancer effectivity. The main reason for the resistance development is the paclitaxel-induced phenomenon of cytoprotective autophagy occurring by different mechanisms of action in dependence on a cell type and possibly even leading to metastases. Paclitaxel also induces autophagy in cancer stem cells, which greatly contributes to tumor resistance development. Paclitaxel anticancer effectivity can be predicted by the presence of several autophagy-related molecular markers, such as tumor necrosis factor superfamily member 13 in triple-negative breast cancer or cystine/glutamate transporter encoded by the SLC7A11 gene in ovarian cancer. Nevertheless, the undesired effects of paclitaxel-induced autophagy can be eliminated by paclitaxel co-administration with autophagy inhibitors, such as chloroquine. Interestingly, in certain cases, it is worthy of potentiating autophagy by paclitaxel combination with autophagy inducers, for instance, apatinib. A modern strategy in anticancer research is also to encapsulate chemotherapeutics into nanoparticle carriers or develop their novel derivatives with improved anticancer properties. Hence, in this review article, we summarize not only the current knowledge of paclitaxel-induced autophagy and its role in cancer resistance but mainly the possible drug combinations based on paclitaxel and their administration in nanoparticle-based formulations as well as paclitaxel analogs with autophagy-modulating properties.

Glycolytic Inhibitors Potentiated the Activity of Paclitaxel and Their Nanoencapsulation Increased Their Delivery in a Lung Cancer Model

Antiglycolytic agents inhibit cell metabolism and modify the tumor’s microenvironment, affecting chemotherapy resistance mechanisms. In this work, we studied the effect of the glycolytic inhibitors 3-bromopyruvate (3BP), dichloroacetate (DCA) and 2-deoxyglucose (2DG) on cancer cell properties and on the multidrug resistance phenotype, using lung cancer cells as a model. All compounds led to the loss of cell viability, with different effects on the cell metabolism, migration and proliferation, depending on the drug and cell line assayed. DCA was the most promising compound, presenting the highest inhibitory effect on cell metabolism and proliferation. DCA treatment led to decreased glucose consumption and ATP and lactate production in both A549 and NCI-H460 cell lines. Furthermore, the DCA pretreatment sensitized the cancer cells to Paclitaxel (PTX), a conventional chemotherapeutic drug, with a 2.7-fold and a 10-fold decrease in PTX IC₅₀ values in A549 and NCI-H460 cell lines, respectively. To increase the intracellular concentration of DCA, thereby potentiating its effect, DCA-loaded poly(lactic-co-glycolic acid) nanoparticles were produced. At higher DCA concentrations, encapsulation was found to increase its toxicity. These results may help find a new treatment strategy through combined therapy, which could open doors to new treatment approaches.

Triple negative breast cancer: approved treatment options and their mechanisms of action

PURPOSE

Breast cancer, the most prevalent cancer worldwide, consists of 4 main subtypes, namely, Luminal A, Luminal B, HER2-positive, and Triple-negative breast cancer (TNBC). Triple-negative breast tumors, which do not express estrogen, progesterone, and HER2 receptors, account for approximately 15-20% of breast cancer cases. The lack of traditional receptor targets contributes to the heterogenous, aggressive, and refractory nature of these tumors, resulting in limited therapeutic strategies.

METHODS

Chemotherapeutics such as taxanes and anthracyclines have been the traditional go to treatment regimens for TNBC patients. Paclitaxel, docetaxel, doxorubicin, and epirubicin have been longstanding, Food and Drug Administration (FDA)-approved therapies against TNBC. Additionally, the FDA approved PARP inhibitors such as olaparib and atezolizumab to be used in combination with chemotherapies, primarily to improve their efficiency and reduce adverse patient outcomes. The immunotherapeutic Keytruda was the latest addition to the FDA-approved list of drugs used to treat TNBC.

RESULTS

The following review aims to elucidate current FDA-approved therapeutics and their mechanisms of action, shedding a light on the various strategies currently used to circumvent the treatment-resistant nature of TNBC cases.

CONCLUSION

The recent approval and use of therapies such as Trodelvy, olaparib and Keytruda has its roots in the development of an understanding of signaling pathways that drive tumour growth. In the future, the emergence of novel drug delivery methods may help increase the efficiency of these therapies whiel also reducing adverse side effects.

Oxidative stress-mediated up-regulation of ABC transporters in lung cancer cells

This paper aimed to evaluate the role of oxidative stress in the regulation of ABC transporters in human lung cancer (A549) cells facing substrate (doxorubicin, DOX) and non-substrate (ethanol, ETH and hydrogen peroxide, HP) chemicals. After 24-h treatment, all the chemicals caused significant cytotoxicity as reflected by the reduction in cell viability and the increase in reactive oxygen species (ROS) levels. Depending on the rescuing effects of ROS scavenger including glutathione (GSH) and Vitamin C (VC), the toxicity dependence on oxidative stress were found to be HP>ETH>DOX. Addition of transporter inhibitors significantly enhanced the ROS levels and death-inducing effects of chemicals, indicating the universal detoxification function of ABC transporters. At moderate ROS levels (about 3-4 folds of control levels, caused by 10 μM DOX, 400 mM ETH, and 400 μM HP), all the three chemicals induced the gene expressions and activities of ABC transporters, but these values decreased at too high ROS levels (8.36 folds of control levels) caused by HP at LC₅₀ (800 μM). Such induction could be attenuated by GSH and KCZ, and was completely abolished by 50 μM KCZ, indicating an important role of oxidative stress and pregnane X receptor (PXR) in the induction of ABC transporters. After all, this paper revealed a critical role of oxidative stress in the modulation of ABC transporters by either substrate or non-substrate chemicals during 24-h treatment. Such information should be beneficial for overcoming ABC transporter-mediated multidrug resistance (MDR). This article is protected by copyright. All rights reserved.

PI3K inhibitor 3-MA promotes the antiproliferative activity of esomeprazole in gastric cancer cells by downregulating EGFR via the PI3K/FOXO3a pathway

Gastric cancer is a common gastrointestinal malignancy worldwide, with a high mortality rate and poor prognosis. Esomeprazole (ESO) has been shown to have anticancer activity by affecting cell growth and autophagy and its mechanism in gastric cancer cells is evident. The PI3K/AKT/FOXO3a pathway is central in cancers. 3-Methyladenine (3-MA), a dual inhibitor of PI3K and autophagy, plays a synergistic role in combination with antitumor agents. In this study, we assessed the role of ESO on the PI3K/AKT/FOXO3a pathway and the beneficial effects of ESO combined with 3-MA in gastric cancer cells. Cell viability, proliferation, invasion, migration, apoptosis, autophagy, and protein expression were detected by CCK-8, EdU, Transwell, flow cytometry, immunofluorescence assay, and western blot. ESO decreased cell viability in a concentration- and time-dependent manner and increased autophagy with upregulation of LC3II and P62. Additionally, ESO inhibited the proliferation, migration, and invasion and induced the apoptosis of gastric cancer cells in a concentration-dependent manner. ESO inhibited PI3K/AKT/FOXO3a signaling and EGFR and SKP2 expression concentration-dependent. 3-MA enhanced the antiproliferative activity of ESO and synergistically inhibited PI3K/FOXO3a signaling and the expression of EGFR but not SKP2. Furthermore, pretreatment with the EGFR inhibitor AG1478 enhanced the antiproliferative activity of ESO in gastric cancer cells. In conclusion, our results suggested that the PI3K inhibitor 3-MA promotes the antiproliferative activity of ESO in gastric cancer cells by synergistically downregulating EGFR via the PI3K/FOXO3a pathway.

mPEG-Cholic acid/TPGS mixed micelles for combined delivery of paclitaxel and bufalin to treat hepatocellular carcinoma

In this study, amphiphilic block copolymer mPEG-cholic acid was synthesized in conjunction with TPGS as stabilizer to prepare multifunctional micelles. The formed polymeric micelles (PCTm) were used for the delivery of paclitaxel (PTX) and bufalin (BF). PEG group could enhance solubility and extend circulation time, while cholic acid groups achieved the liver targeted function. Combinations of these approaches could realize a synergistic therapeutic effect in the treatment of advanced hepatocellular carcinoma. CLSM in vitro results demonstrated that drug capsulation into PCTm could enhance cellular uptake. FCM results confirmed the uptake amount of C₆/PCTm was 7.5-fold higher than that of free C₆ after incubation for 2 h. Competitive inhibition test proved the Na⁺-taurocholate co-transporting polypeptide (NTCP) involved in the uptake mechanism of PCTm. Meanwhile, in vivo imaging assays demonstrated that the fluorescence intensity of Cy5.5/PCTm was higher than that of free Cy5.5 on liver and tumor with extended circulation time to 48 h. In addition, in vivo studies confirmed that the combined therapy exhibited the strongest tumor inhibition rate of 82.29% with lower systemic toxicity. Hence, these results indicated that PCTm could provide a promising strategy for targeting hepatocellular carcinoma and achieve the goal of the synergism and attenuation.

Targeting Autophagy with Natural Compounds in Cancer: A Renewed Perspective from Molecular Mechanisms to Targeted Therapy

Natural products are well-characterized to have pharmacological or biological activities that can be of therapeutic benefits for cancer therapy, which also provide an important source of inspiration for discovery of potential novel small-molecule drugs. In the past three decades, accumulating evidence has revealed that natural products can modulate a series of key autophagic signaling pathways and display therapeutic effects in different types of human cancers. In this review, we focus on summarizing some representative natural active compounds, mainly including curcumin, resveratrol, paclitaxel, Bufalin, and Ursolic acid that may ultimately trigger cancer cell death through the regulation of some key autophagic signaling pathways, such as RAS-RAF-MEK-ERK, PI3K-AKT-mTOR, AMPK, ULK1, Beclin-1, Atg5 and p53. Taken together, these inspiring findings would shed light on exploiting more natural compounds as candidate small-molecule drugs, by targeting the crucial pathways of autophagy for the future cancer therapy.

Platinum drugs and taxanes: can we overcome resistance?

Cancer therapy is aimed at the elimination of tumor cells and acts via the cessation of cell proliferation and induction of cell death. Many research publications discussing the mechanisms of anticancer drugs use the terms "cell death" and "apoptosis" interchangeably, given that apoptotic pathways are the most common components of the action of targeted and cytotoxic compounds. However, there is sound evidence suggesting that other mechanisms of drug-induced cell death, such as necroptosis, ferroptosis, autophagy, etc. may significantly contribute to the fate of cancer cells. Molecular cross-talks between apoptotic and nonapoptotic death pathways underlie the successes and the failures of therapeutic interventions. Here we discuss the nuances of the antitumor action of two groups of the widely used anticancer drugs, i.e., platinum salts and taxane derivatives. The available data suggest that intelligent interference with the choice of cell death pathways may open novel opportunities for cancer treatment.

New insight towards development of paclitaxel and docetaxel resistance in cancer cells: EMT as a novel molecular mechanism and therapeutic possibilities

Epithelial-to-mesenchymal transition (EMT) mechanism is responsible for metastasis and migration of cancer cells to neighboring cells and tissues. Morphologically, epithelial cells are transformed to mesenchymal cells, and at molecular level, E-cadherin undergoes down-regulation, while an increase occurs in N-cadherin and vimentin levels. Increasing evidence demonstrates role of EMT in mediating drug resistance of cancer cells. On the other hand, paclitaxel (PTX) and docetaxel (DTX) are two chemotherapeutic agents belonging to taxene family, capable of inducing cell cycle arrest in cancer cells via preventing microtubule depolymerization. Aggressive behavior of cancer cells resulted from EMT-mediated metastasis can lead to PTX and DTX resistance. Upstream mediators of EMT such as ZEB1/2, TGF-β, microRNAs, and so on are involved in regulating response of cancer cells to PTX and DTX. Tumor-suppressing factors inhibit EMT to promote PTX and DTX sensitivity of cancer cells. Furthermore, three different strategies including using anti-tumor compounds, gene therapy and delivery systems have been developed for suppressing EMT, and enhancing cytotoxicity of PTX and DTX against cancer cells that are mechanistically discussed in the current review.

Emerging insights on the role of V-ATPase in human diseases: Therapeutic challenges and opportunities

The control of the intracellular pH is vital for the survival of all organisms. Membrane transporters, both at the plasma and intracellular membranes, are key players in maintaining a finely tuned pH balance between intra- and extracellular spaces, and therefore in cellular homeostasis. V-ATPase is a housekeeping ATP-driven proton pump highly conserved among prokaryotes and eukaryotes. This proton pump, which exhibits a complex multisubunit structure based on cell type-specific isoforms, is essential for pH regulation and for a multitude of ubiquitous and specialized functions. Thus, it is not surprising that V-ATPase aberrant overexpression, mislocalization, and mutations in V-ATPase subunit-encoding genes have been associated with several human diseases. However, the ubiquitous expression of this transporter and the high toxicity driven by its off-target inhibition, renders V-ATPase-directed therapies very challenging and increases the need for selective strategies. Here we review emerging evidence linking V-ATPase and both inherited and acquired human diseases, explore the therapeutic challenges and opportunities envisaged from recent data, and advance future research avenues. We highlight the importance of V-ATPases with unique subunit isoform molecular signatures and disease-associated isoforms to design selective V-ATPase-directed therapies. We also discuss the rational design of drug development pipelines and cutting-edge methodological approaches toward V-ATPase-centered drug discovery. Diseases like cancer, osteoporosis, and even fungal infections can benefit from V-ATPase-directed therapies.

The Dual Role of Autophagy in Cancer Development and a Therapeutic Strategy for Cancer by Targeting Autophagy

Autophagy is a delicate intracellular degradation process that occurs due to diverse stressful conditions, including the accumulation of damaged proteins and organelles as well as nutrient deprivation. The mechanism of autophagy is initiated by the creation of autophagosomes, which capture and encapsulate abnormal components. Afterward, autophagosomes assemble with lysosomes to recycle or remove degradative cargo. The regulation of autophagy has bipolar roles in cancer suppression and promotion in diverse cancers. Furthermore, autophagy modulates the features of tumorigenesis, cancer metastasis, cancer stem cells, and drug resistance against anticancer agents. Some autophagy regulators are used to modulate autophagy for anticancer therapy but the dual roles of autophagy limit their application in anticancer therapy, and present as the main reason for therapy failure. In this review, we summarize the mechanisms of autophagy, tumorigenesis, metastasis, cancer stem cells, and resistance against anticancer agents. Finally, we discuss whether targeting autophagy is a promising and effective therapeutic strategy in anticancer therapy.

A Compressive Review about Taxol®: History and Future Challenges

Taxol^®, which is also known as paclitaxel, is a chemotherapeutic agent widely used to treat different cancers. Since the discovery of its antitumoral activity, Taxol^® has been used to treat over one million patients, making it one of the most widely employed antitumoral drugs. Taxol^® was the first microtubule targeting agent described in the literature, with its main mechanism of action consisting of the disruption of microtubule dynamics, thus inducing mitotic arrest and cell death. However, secondary mechanisms for achieving apoptosis have also been demonstrated. Despite its wide use, Taxol^® has certain disadvantages. The main challenges facing Taxol^® are the need to find an environmentally sustainable production method based on the use of microorganisms, increase its bioavailability without exerting adverse effects on the health of patients and minimize the resistance presented by a high percentage of cells treated with paclitaxel. This review details, in a succinct manner, the main aspects of this important drug, from its discovery to the present day. We highlight the main challenges that must be faced in the coming years, in order to increase the effectiveness of Taxol^® as an anticancer agent.