Combination Treatment With Inhibitors of ERK and Autophagy Enhances Antitumor Activity of Betulinic Acid in Non-small-Cell Lung Cancer In Vivo and In Vitro

Chlorogenic Acid Enhances Beta-Lapachone-Induced Cell Death by Suppressing Autophagy in NQO1-Positive Cancer Cells

Resistance to apoptosis-inducing drugs frequently occurs in cancer cells, limiting their usefulness in ongoing cancer treatment. Despite ongoing efforts to overcome drug resistance, a definitive solution remains elusive. However, autophagy inhibition has been shown to enhance the effectiveness of some anticancer drugs and is a possible strategy for overcoming drug resistance. In this study, we demonstrate that chlorogenic acid (CGA), a natural antioxidant, significantly enhances beta-lapachone (β-Lap)-induced cell death in cancer cells. The augmented apoptosis induced by CGA is associated with activation of protein kinase A (PKA) in β-Lap-treated cells, independent of the antioxidant properties of CGA. As a result, PKA activation in cancer cells co-treated with β-Lap and CGA effectively inhibits autophagy. Notably, PKA activation leads to phosphorylation of microtubule-associated protein 1 A/1B-light chain 3 (LC3) at the serine 12 residue, causing autophagy suppression irrespective of mTORC activity. Importantly, the cell death induced by β-Lap and CGA in NQO1-overexpressing breast or lung cancers is closely linked to autophagy inhibition. These findings suggest that combining β-Lap and CGA might be a novel strategy for cancer therapy, particularly for overcoming drug resistance caused by autophagy induction in cancer cells.

The Effects of Silibinin Combined With EGFR-TKIs in the Treatment of NSCLC

BACKGROUND

Currently, the most effective oral targeted therapies for NSCLC in clinical practice are EGFR-TKIs. However, acquired drug resistance often leads to tumor progression and recurrence. EGFR overexpression and activation of its downstream pathways are primary contributors to both mutations in tumor cells and their development of drug resistance. Silibinin has been identified as a promising agent that can suppress EGFR signaling through multiple mechanisms. However, its poor water solubility and difficulty penetrating cell membranes result in rapid metabolism in vivo, and significantly affect its concentration in the blood.

METHODS

We conducted a comprehensive search of the English PubMed database using various combinations of keywords, including "silibinin," "epidermal growth factor receptor," "phosphorylation," "chemotherapy," "nano," and "non-small cell lung cancer." The results were then filtered for their relevance and impact on current treatment paradigms.

RESULTS

This review presents a comprehensive exploration of the mechanisms underlying the EGFR autophosphorylation pathways that contribute to acquire drug resistance in. Additionally, this study delves into the potential of silibinin as a novel therapeutic agent for NSCLC, evaluating its advantages and limitations on the basis of existing research. The majority of the available data suggest that combining silibinin with first-generation TKIs would yield promising outcomes because of additive or synergistic effects, suggesting that optimizing the time and dosage of each of these treatments is crucial for achieving the best results.

CONCLUSION

The existing evidence is inadequate to endorse the clinical application of nano silibinin for NSCLC treatment. Developing multifunctional nanomedicines that incorporate silibinin, EGFR-TKIs, and other bioactive compounds is a recommended future strategy for NSCLC treatment.

The Role of Pentacyclic Triterpenoids in Non-Small Cell Lung Cancer: The Mechanisms of Action and Therapeutic Potential

Lung cancer remains a major global health problem because of its high cancer-related mortality rate despite advances in therapeutic approaches. Non-small cell lung cancer (NSCLC), a major subtype of lung cancer, is more amenable to surgical intervention in its early stages. However, the prognosis for advanced NSCLC remains poor, owing to limited treatment options. This underscores the growing need for novel therapeutic strategies to complement existing treatments and improve patient outcomes. In recent years, pentacyclic triterpenoids, a group of natural compounds, have emerged as promising candidates for cancer therapy due to their anticancer properties. Pentacyclic triterpenoids, such as lupeol, betulinic acid, betulin, oleanolic acid, ursolic acid, glycyrrhetinic acid, glycyrrhizin, and asiatic acid, have demonstrated the ability to inhibit cell proliferation and angiogenesis, induce apoptosis, suppress metastasis, and modulate inflammatory and immune pathways in NSCLC cell line models. These compounds exert their effects by modulating important signaling pathways such as NF-κB, PI3K/Akt, and MAPK. Furthermore, advances in drug delivery technologies such as nanocarriers and targeted delivery systems have improved the bioavailability and therapeutic efficacy of triterpenoids. However, despite promising preclinical data, rigorous clinical trials are needed to verify their safety and efficacy. This review explores the role of triterpenoids in NSCLC and therapeutic potential in preclinical models, focusing on their molecular mechanisms of action.

Metabolic and Regulatory Pathways Involved in the Anticancer Activity of Perillyl Alcohol: A Scoping Review of In Vitro Studies

BACKGROUND/OBJECTIVES

Perillyl alcohol (POH), a plant-derived compound, has demonstrated anti-tumor activity across various human cancers. Understanding the regulatory pathways through which POH exerts its effects is crucial for identifying new therapeutic opportunities and exploring potential drug repositioning strategies. Therefore, this scoping review aims to provide a comprehensive overview of the metabolic and regulatory pathways involved in the anticancer effects of POH, based on in vitro evidence.

METHODS

Following the PRISMA-ScR 2018 guidelines, a systematic search was conducted in the PUBMED, Web of Science, and Scopus databases.

RESULTS

A total of 39 studies were included, revealing that POH exerts its biological effects by modulating several pathways, including the regulation of cyclins, CDKs, and p21, thereby affecting cell cycle progression. It inhibits growth and promotes cell death by attenuating AKT phosphorylation, reducing PARP-1 activity, increasing caspase activity and the FAS receptor and its ligand FASL. Additionally, POH reduces ERK phosphorylation, inhibits RAS protein isoprenylation, and decreases Na/K-ATPase activity.

CONCLUSIONS

In conclusion, this review delineates the key regulatory pathways responsible for mediating the biological effects of POH in cancer.

DEPDC1 affects autophagy-dependent glycolysis levels in human osteosarcoma cells by modulating RAS/ERK signaling through TTK

The current treatment for osteosarcoma (OS) is based on surgery combined with systemic chemotherapy, however, gene therapy has been hypothesized to improve patient survival rates. The density-enhanced protein domain 1 protein (DEPDC1) functions as a crucial determinant in the advancement of OS, which is highly expressed in OS cells. The current study was designed to delve into the effect and mechanism of DEPDC1 and phosphotyrosine-picked threonine tyrosine kinase (TTK) in OS. The expression of DEPDC1 and TTK in OS cells was detected by western blotting. Furthermore, the assessment of glycolysis encompassed the quantification of extracellular acidification rate, glucose uptake rate, lactate concentration, and the expression of glucose transporter 1, hexokinase 2, and pyruvate kinase M2. Finally, the functions of DEPDC1 and TTK in autophagy and ras-extracellular signal-regulated kinase signaling were determined by western blotting after interfering with DEPDC1 in SaOS-2 cells. The results revealed that DEPDC1 and TTK were upregulated in OS cell lines and interfering with DEPDC1 inhibited glycolysis and autophagy in OS cells. Furthermore, the STRING database suggested that DEPDC1 and TTK perform targeted binding. Notably, the results of the present study revealed that DEPDC1 upregulated RAS expression through TTK and enhanced ERK activity, thereby affecting glycolysis and autophagy in OS cells. Collectively, the present investigation demonstrated that DEPDC1 affected autophagy-dependent glycolysis levels of OS cells by regulating RAS/ERK signaling through TTK.

Targeting the p90RSK/MDM2/p53 Pathway Is Effective in Blocking Tumors with Oncogenic Up-Regulation of the MAPK Pathway Such as Melanoma and Lung Cancer

In most human tumors, the MAPK pathway is constitutively activated. Since p90RSK is downstream of MAPK, it is often hyperactive and capable of phosphorylating oncogenic substrates. We have previously shown that p90RSK phosphorylates MDM2 at S166, promoting p53 degradation in follicular thyroid carcinomas. Thus, the inhibition of p90RSK restores p53 expression, which in turn inhibits cell proliferation and promotes apoptosis. In the present study, we demonstrated that the p90RSK/MDM2/p53 pathway proved to be an excellent target in the therapy of tumors with MAPK hyperactivation. For this purpose, we selected p53wt melanoma, lung and medullary thyroid carcinoma cell lines with high activation of p90RSK. In these cell lines, we demonstrated that the p90RSK/MDM2/p53 pathway is implicated in the regulation of the cell cycle and apoptosis through p53-dependent transcriptional control of p21 and Bcl-2. Furthermore, with an immunohistochemical evaluation of primary melanomas and lung tumors, which exhibit highly activated p90RSK compared to corresponding normal tissue, we demonstrated that MDM2 stabilization was associated with p90RSK phosphorylation. The results indicate that p90RSK is able to control the proliferative rate and induction of apoptosis through the regulation of p53wt levels by stabilizing MDM2 in selected tumors with constitutively activated MAPKs, making p90RSK a new attractive target for anticancer therapy.

Promising Combinatorial Therapeutic Strategies against Non-Small Cell Lung Cancer

Non-small cell lung cancer (NSCLC) presents a complex and diverse disease, exhibiting variations at individuals' cellular and histological levels. This complexity gives rise to different subtypes and genetic mutations, posing challenges for accurate diagnosis and effective treatment. Nevertheless, continuous progress in medical research and therapies is continually shaping the landscape of NSCLC diagnosis and management. The treatment of NSCLC has undergone significant advancements in recent years, especially with the emergence of targeted therapies that have shown remarkable efficacy in patients with actionable mutations. This has ushered in the era of personalized medicine in NSCLC treatment, with improvements in molecular and immunohistochemical techniques contributing to enhanced progression-free survival. This review focuses on the latest progress, challenges, and future directions in developing targeted therapies for NSCLC, including tyrosine kinase inhibitors (TKIs), DNA-damaging agents, immunotherapy regimens, natural drug therapy, and nanobodies. Furthermore, recent randomized studies have demonstrated enhanced overall survival in patients receiving different targeted and natural drug therapies.

Prioritization of bioactive compounds envisaging yohimbine as a multi targeted anticancer agent: insight from molecular docking and molecular dynamics simulation

Recently, multi-targeted drugs have attracted much attention in cancer therapy where several therapeutic proteins are targeted by a single agent. Using the published scientific literature, we selected sixteen well-known anticancer targets and seven potential phytobioactive chemicals to find a multitargeted compound by screening through molecular docking. The feasible protein-ligand interaction was further predicted by protein-ligand interaction analysis and molecular dynamic simulation. The phytochemical yohimbine exhibited the lowest docking score in the range of -8.3 to -10.0 kcal/mol over other ligands with all the studied protein targets. Molecular interaction data also revealed the feasible binding of yohimbine with all targets. Moreover, the molecular simulation data also confirmed the stability of protein-ligand complexes with three most scored targets viz. ERK2, PARP1 and PIK3α. Based on our results, yohimbine seems to be the most potent compound out of those selected compounds and can be considered as effective lead molecule against the studied target proteins.Communicated by Ramaswamy H. Sarma.

Focusing on the Role of Natural Products in Overcoming Cancer Drug Resistance: An Autophagy-Based Perspective

Autophagy is a critical cellular adaptive response in tumor formation. Nutritional deficiency and hypoxia exacerbate autophagic flux in established malignancies, promoting tumor cell proliferation, migration, metastasis, and resistance to therapeutic interventions. Pro-survival autophagy inhibition may be a promising treatment option for advanced cancer. Furthermore, excessive or persistent autophagy is cytotoxic, resulting in tumor cell death. Targeted autophagy activation has also shown significant promise in the fight against tumor drug resistance. Several research groups have examined the ability of natural products (NPs) such as alkaloids, terpenoids, polyphenols, and anthraquinones to serve as autophagy inhibitors or activators. The data support the capacity of NPs that promote lethal autophagy or inhibit pro-survival autophagy from being employed against tumor drug resistance. This paper discusses the potential applications of NPs that regulate autophagy in the fight against tumor drug resistance, some limitations of the current studies, and future research needs and priorities.

Development of a novel cell-based, In-Cell Western/ERK assay system for the high-throughput screening of agonists acting on the delta-opioid receptor

Background: Extracellular signal-regulated kinases (ERKs) are important signaling mediators in mammalian cells and, as a result, one of the major areas of research focus. The detection and quantification of ERK phosphorylation as an index of activation is normally conducted using immunoblotting, which does not allow high-throughput drug screening. Plate-based immunocytochemical assays provide a cheaper and relatively high-throughput alternative method for quantifying ERK phosphorylation. Here, we present optimization steps aimed to increase assay sensitivity and reduce variance and cost using the LI-COR In-Cell Western (I-CW) system in a recombinant CHO-K1 cell line, over-expressing the human delta-opioid receptor (hDOPr) as a model.

Methods: Cells cultured in 96-well microassay plates were stimulated with three standard/selective DOPr agonists (SNC80, ADL5859, and DADLE) and a novel selective DOPr agonist (PN6047) to elicit a phospho-ERK response as an index of activation. A number of experimental conditions were investigated during the assay development.

Key results: Preliminary experiments revealed a clearly visible edge-effect which significantly increased assay variance across the plate and which was reduced by pre-incubation for 30 min at room temperature. ERK phosphorylation was detectable as early as 1 min after agonist addition, with a distinct peak at 3–5 min. Optimization of the cell seeding densities showed that 25,000 cells per well have the lowest basal phospho-ERK response and an optimal agonist ERK1/2 signal. Pre-incubation with apyrase (an ATPase) did not reduce the basal or agonist responses. All agonists produced concentration-dependent increases in phospho-ERK activation, and pertussis toxin was able to attenuate these ERK responses. Naltrindole, which is a selective DOPr antagonist, was able to antagonize the DOPr-mediated ERK activation of the ligands.

Conclusion: We have developed an optimization protocol and highlighted a number of considerations when performing this high-throughput fluorescence immunocytochemical (ICC) assay measuring ERK phosphorylation in the human DOPr. The optimized protocol was found to be a more conducive option for the screening of delta agonists. This provides a basis for additional assay development to investigate opioid pharmacology. This protocol should be widely applicable for measuring ERK phosphorylation in any cell line and investigating other protein targets in GPCR drug discovery.

Gilteritinib Enhances Anti-Tumor Efficacy of CDK4/6 Inhibitor, Abemaciclib in Lung Cancer Cells

Abemaciclib is a cyclin-dependent kinases 4/6 (CDK4/6) inhibitor approved for the treatment of metastatic breast cancer. Preclinical studies suggest that abemaciclib has the potential for lung cancer treatment. However, several clinical trials demonstrate that monotherapy with abemaciclib has no obvious superiority than erlotinib to treat lung cancer patients, limiting its therapeutic options for lung cancer treatment. Here, we show that the US Food and Drug Administration (FDA)-approved drug, gilteritinib, enhances the cytotoxicity of abemaciclib through inducing apoptosis and senescence in lung cancer cells. Interestingly, abemaciclib in combination with gilteritinib leads to excessive accumulation of vacuoles in lung cancer cells. Mechanistically, combined abemaciclib and gilteritinib induces complete inactivation of AKT and retinoblastoma (Rb) pathways in lung cancer cells. In addition, RNA-sequencing data demonstrate that combination of abemaciclib and gilteritinib treatment induces G2 phase cell-cycle arrest, inhibits DNA replication, and leads to reduction in homologous recombination associated gene expressions. Of note, abemaciclib-resistant lung cancer cells are more sensitive to gilteritinib treatment. In a mouse xenograft model, combined abemaciclib and gilteritinib is more effective than either drug alone in suppressing tumor growth and appears to be well tolerated. Together, our findings support the combination of abemaciclib with gilteritinib as an effective strategy for the treatment of lung cancer, suggesting further evaluation of their efficacy is needed in a clinical trial.

Biodegradable and Bioactive Carriers Based on Poly(betulin disuccinate-co-sebacic Acid) for Rifampicin Delivery

This paper describes the preparation and characterization of polymer-drug systems based on polymeric microspheres obtained from poly(betulin disuccinate-co-sebacic acid). The active compound that was coupled to the betulin-based carriers was rifampicin (RIF), an ansamycin drug used in the treatment of tuberculosis. Poly(betulin disuccinate-co-sebacic acid) microspheres were prepared using a solvent evaporation technique from copolymers obtained by polycondensation of betulin disuccinate (DBB) and sebacic acid (SEB). The content of sebacic acid in the copolymers was 20, 40, 60 and 80 wt%, respectively. Small and large rifampicin-loaded microspheres were obtained for each of the copolymers. The initial amount of drug was 10, 30 or 50 wt%, based on the weight of the polymer. Particles obtained in this study were round in shape with diameter in the range of 2-21 μm and of orange to red colour originating from rifampicin. The RIF encapsulation efficacy varied from 7% to 33%. Drug loading varied from 2% to 13% and increased at a higher RIF ratio. The highest degree of drug loading was observed for large particles, in which the initial amount of drug (at the particle preparation stage) was 50 wt%. Microspheres prepared from betulin-based polyanhydrides may have significant applications in drug delivery systems. The concentration of loaded drug was enough to obtain bactericidal effects against reference S. Aureus ATCC 25923 bacteria.

The Effect of Terpenoid Natural Chinese Medicine Molecular Compound on Lung Cancer Treatment

Among all malignant tumors in the whole universe, the incidence and mortality of lung cancer disease rank first. Especially in the past few years, the occurrence of lung cancer in the urban population has continued to increase, which seriously threatens the lives and health of people. Among the many treatments for lung cancer, chemotherapy is the best one, but traditional chemotherapy has low specificity and drug resistance. To address the above issue, this study reviews the five biological pathways that common terpenoid compounds in medicinal plants interfere with the occurrence and development of lung cancer: cell proliferation, cell apoptosis, cell autophagy, cell invasion, metastasis, and immune mechanism regulation. In addition, the mechanism of the terpenoid natural traditional Chinese medicine monomer compound combined with Western medicine in the multipathway antilung cancer is summarized.