Identification of Proteins Deregulated by Platinum-Based Chemotherapy as Novel Biomarkers and Therapeutic Targets in Non-Small Cell Lung Cancer

Trilobolide-6-O-isobutyrate from Sphagneticola trilobata acts by inducing oxidative stress, metabolic changes and apoptosis-like processes by caspase 3/7 activation of human lung cancer cell lines

BACKGROUND

Lung cancer, a chronic and heterogeneous disease, is the leading cause of cancer-related death on a global scale. Presently, despite a variety of available treatments, their effectiveness is limited, often resulting in considerable toxicity and adverse effects. Additionally, the development of chemoresistance in cancer cells poses a challenge. Trilobolide-6-O-isobutyrate (TBB), a natural sesquiterpene lactone extracted from Sphagneticola trilobata, has exhibited antitumor effects. Its pharmacological properties in NSCLC lung cancer, however, have not been explored.

PURPOSE

This study evaluated the impact of TBB on the A549 and NCI-H460 tumor cell lines in vitro, examining its antiproliferative properties and initial mechanisms of cell death.

METHODS

TBB, obtained at 98 % purity from S. trilobata leaves, was characterized using chromatographic techniques. Subsequently, its impact on inhibiting tumor cell proliferation in vitro, TBB-induced cytotoxicity in LLC-MK2, THP-1, AMJ2-C11 cells, as well as its effects on sheep erythrocytes, and the underlying mechanisms of cell death, were assessed.

RESULTS

In silico predictions have shown promising drug-likeness potential for TBB, indicating high oral bioavailability and intestinal absorption. Treatment of A549 and NCI-H460 human tumor cells with TBB demonstrated a direct impact, inducing significant morphological and structural alterations. TBB also reduced migratory capacity without causing toxicity at lower concentrations to LLC-MK2, THP-1 and AMJ2-C11 cell lines. This antiproliferative effect correlated with elevated oxidative stress, characterized by increased levels of ROS, superoxide anion radicals and NO, accompanied by a decrease in antioxidant markers: SOD and GSH. TBB-stress-induced led to changes in cell metabolism, fostering the accumulation of lipid droplets and autophagic vacuoles. Stress also resulted in compromised mitochondrial integrity, a crucial aspect of cellular function. Additionally, TBB prompted apoptosis-like cell death through activation of caspase 3/7 stressors.

CONCLUSION

These findings underscore the potential of TBB as a promising candidate for future studies and suggest its viability as an additional component in the development of novel anticancer drugs prototypes.

Exploring the potential of phytochemicals as inhibitors of 3'-phosphoadenosine 5'-phosphosulfate synthase 1 targeting cancer therapy

3'-phosphoadenosine 5'-phosphosulfate synthase 1 (PAPSS1) is an enzyme that critically synthesises the biologically active form of sulfate (PAPS) for all sulfation reactions. The discovery of PAPSS1 as a possible drug target for cancer therapy, specifically in non-small cell lung cancer, has prompted us to investigate potential small-molecule inhibitors of PAPSS1. Here, a structure-based virtual screening method was used to search for phytochemicals in the IMPPAT database to find potential inhibitors of PAPSS1. The primary hits were selected based on their physicochemical, ADMET, and drug-like properties. Then, the binding affinities were calculated and analyzed the interactions to identify safer and more effective hits. The research identified two phytochemicals, Guggulsterone and Corylin, that exhibited significant affinity and specific interaction with the ATP-binding pocket of PAPSS1. Structural observations made by molecular docking were further accompanied by molecular dynamics (MD) simulations and principal component analysis (PCA) to examine the conformational changes and stability of PAPSS1 with the elucidated compounds Guggulsterone and Corylin. MD simulation results suggested that the binding of Guggulsterone and Corylin stabilizes the PAPSS1 structure, leading to fewer conformational changes. This implies that these compounds may be useful in developing PAPSS1 inhibitors for the therapeutic development against non-small cell lung cancer (NSCLC). This study highlights the potential of phytochemicals as PAPSS1 inhibitors and the utility of computational approaches in drug discovery.Communicated by Ramaswamy H. Sarma.

Inhibition of Aurora B kinase (AURKB) enhances the effectiveness of 5-fluorouracil chemotherapy against colorectal cancer cells

BACKGROUND

5-Fluorouracil (5-FU) remains a core component of systemic therapy for colorectal cancer (CRC). However, response rates remain low, and development of therapy resistance is a primary issue. Combinatorial strategies employing a second agent to augment the therapeutic effect of chemotherapy is predicted to reduce the incidence of treatment resistance and increase the durability of response to therapy.

METHODS

Here, we employed quantitative proteomics approaches to identify novel druggable proteins and molecular pathways that are deregulated in response to 5-FU, which might serve as targets to improve sensitivity to chemotherapy. Drug combinations were evaluated using 2D and 3D CRC cell line models and an ex vivo culture model of a patient-derived tumour.

RESULTS

Quantitative proteomics identified upregulation of the mitosis-associated protein Aurora B (AURKB), within a network of upregulated proteins, in response to a 24 h 5-FU treatment. In CRC cell lines, AURKB inhibition with the dihydrogen phosphate prodrug AZD1152, markedly improved the potency of 5-FU in 2D and 3D in vitro CRC models. Sequential treatment with 5-FU then AZD1152 also enhanced the response of a patient-derived CRC cells to 5-FU in ex vivo cultures.

CONCLUSIONS

AURKB inhibition may be a rational approach to augment the effectiveness of 5-FU chemotherapy in CRC.

Exploring the Molecular Players behind the Potentiation of Chemotherapy Effects by Durvalumab in Lung Adenocarcinoma Cell Lines

Immune checkpoint inhibitors are increasingly used in combination with chemotherapy for the treatment of non-small cell lung cancer, yet the success of combination therapies is relatively limited. Thus, more detailed insight regarding the tumor molecular markers that may affect the responsiveness of patients to therapy is required. Here, we set out to explore the proteome of two lung adenocarcinoma cell lines (HCC-44 and A549) treated with cisplatin, pemetrexed, durvalumab, and the corresponding mixtures to establish the differences in post-treatment protein expression that can serve as markers of chemosensitivity or resistance. The mass spectrometry study showed that the addition of durvalumab to the treatment mixture resulted in cell line- and chemotherapeutic agent-dependent responses and confirmed the previously reported involvement of DNA repair machinery in the potentiation of the chemotherapy effect. Further validation using immunofluorescence also indicated that the potentiating effect of durvalumab in the case of cisplatin treatment was dependent on the tumor suppressor RB-1 in the PD-L1 weakly positive cells. In addition, we identified aldehyde dehydrogenase ALDH1A3 as the general putative resistance marker. Further studies in patient biopsy samples will be required to confirm the clinical significance of these findings.

An explainable AI-driven biomarker discovery framework for Non-Small Cell Lung Cancer classification

Non-Small Cell Lung Cancer (NSCLC) exhibits intrinsic heterogeneity at the molecular level that aids in distinguishing between its two prominent subtypes - Lung Adenocarcinoma (LUAD) and Lung Squamous Cell Carcinoma (LUSC). This paper proposes a novel explainable AI (XAI)-based deep learning framework to discover a small set of NSCLC biomarkers. The proposed framework comprises three modules - an autoencoder to shrink the input feature space, a feed-forward neural network to classify NSCLC instances into LUAD and LUSC, and a biomarker discovery module that leverages the combined network comprising the autoencoder and the feed-forward neural network. In the biomarker discovery module, XAI methods uncovered a set of 52 relevant biomarkers for NSCLC subtype classification. To evaluate the classification performance of the discovered biomarkers, multiple machine-learning models are constructed using these biomarkers. Using 10-Fold cross-validation, Multilayer Perceptron achieved an accuracy of 95.74% (±1.27) at 95% confidence interval. Further, using Drug-Gene Interaction Database, we observe that 14 of the discovered biomarkers are druggable. In addition, 28 biomarkers aid the prediction of the survivability of the patients. Out of 52 discovered biomarkers, we find that 45 biomarkers have been reported in previous studies on distinguishing between the two NSCLC subtypes. To the best of our knowledge, the remaining seven biomarkers have not yet been reported for NSCLC subtyping and could be further explored for their contribution to targeted therapy of lung cancer.

Elevating CDCA3 Levels Enhances Tyrosine Kinase Inhibitor Sensitivity in TKI-Resistant EGFR Mutant Non-Small-Cell Lung Cancer

Tyrosine kinase inhibitors (TKIs) are the first-line therapy for non-small-cell lung cancers (NSCLC) that harbour sensitising mutations within the epidermal growth factor receptor (EGFR). However, resistance remains a key issue, with tumour relapse likely to occur. We have previously identified that cell division cycle-associated protein 3 (CDCA3) is elevated in adenocarcinoma (LUAD) and correlates with sensitivity to platinum-based chemotherapy. Herein, we explored whether CDCA3 levels were associated with EGFR mutant LUAD and TKI response. We demonstrate that in a small-cohort tissue microarray and in vitro LUAD cell line panel, CDCA3 protein levels are elevated in EGFR mutant NSCLC as a result of increased protein stability downstream of receptor tyrosine kinase signalling. Here, CDCA3 protein levels correlated with TKI potency, whereby CDCA3^high EGFR mutant NSCLC cells were most sensitive. Consistently, ectopic overexpression or inhibition of casein kinase 2 using CX-4945, which pharmacologically prevents CDCA3 degradation, upregulated CDCA3 levels and the response of T790M(+) H1975 cells and two models of acquired resistance to TKIs. Accordingly, it is possible that strategies to upregulate CDCA3 levels, particularly in CDCA3^low tumours or upon the emergence of therapy resistance, might improve the response to EGFR TKIs and benefit patients.