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.

Lee BH, et al. J Korean Med Sci. 2015 Jul;30(7):871-875. https://doi.org/10.3346/jkms.2015.30.7.871

Yeo HJ, et al. J Korean Med Sci. 2017 Dec;32(12):1953-1958. https://doi.org/10.3346/jkms.2017.32.12.1953

Background: To identify immunotherapy biomarkers, we examined granzyme B levels in peripheral blood PD-1⁺ CD8⁺ T cells and their relationship with treatment outcomes in patients with non-small cell lung cancer (NSCLC). Methods: To evaluate the association of granzyme B with response to immunotherapy, we tested blood samples obtained from 16 patients with stage IIIC to IV NSCLC receiving immune-checkpoint inhibitor treatment. We used flow cytometry to measure the change in the percentage of PD1⁺ CD8⁺ T cells expressing granzyme B before (t0) and after (t1) immunotherapy, and we evaluated for an association with tumor response to therapy, progression-free survival (PFS) and overall survival (OS). Additionally, we measured immune markers correlated with immunotherapy response by enzyme-linked immunosorbent assay. Results: We found that the sequential change of granzyme B+ T cells after immunotherapy (t1/t0) significantly predicted durable clinical benefit (DCB) compared to no clinical benefit (NCB) (P=0.048), and prolonged PFS (P=0.025). Patients who demonstrated a PD-L1 tumor proportion score (TPS) >50% showed NCB if patients had low granzyme B t1/t0 levels (<0.805). Additionally, all patients with 1% PD-L1 TPS (or higher) and high granzyme B t1/t0 (≥0.805) showed DCB. Therefore, granzyme B t1/t0 may be an adjunctive marker with available PD-L1 TPS. Conclusions: Our findings revealed that sequential change in granzyme B might be utilized as a predictive biomarker of immune checkpoint inhibitor monotherapy.

Background/Aims: p21-activated Ser/Thr kinase 1 (PAK1) is essential for the genesis and development of many cancers. The purpose of this study was to investigate the role of the PAK1–cyclic AMP response element-binding (CREB) axis in non-small cell lung cancer (NSCLC) tumorigenesis and its related mechanisms. Methods: Western blot assay and immunohistochemical staining were employed to investigate the PAK1 and CREB expression in the tissue microarray of human squamous NSCLC. Co-immunoprecipitation and immunofluorescence confocal assays were performed to determine the link between PAK1 and CREB. NSCLC xenograft models were used to study oncogenic function of PAK1 in vivo. Results: We observed that PAK1 and CREB expression levels were significantly elevated in human squamous NSCLC-tissue specimens, compared with those in adjacent normal bronchial or bronchiolar epithelial-tissue specimens, as well as their phosphorylated forms, based on western blotting. We showed in vitro that PAK1 knockdown by small-interfering RNA (siRNA) blocked CREB phosphorylation, whereas plasmid-based PAK1 overexpression resulted in CREB phosphorylation at Ser133, based on western blotting. In addition, PAK1 interacted with CREB in co-immunoprecipitation assays. Additionally, our in vitro findings detected by flow cytometry revealed that PAK1 silencing attenuated cell cycle progression, inducing apoptosis. Inhibition of PAK1 expression reduced tumor sizes and masses by modulating CREB expression and activation in xenograft models. Conclusion: These results suggest a novel mechanism whereby the PAK1–CREB axis drives carcinogenesis of squamous-cell carcinomas, and have important implications in the development of targeted therapeutics for squamous-cell lung cancer.