Targeting Cell Signaling Pathways in Lung Cancer by Bioactive Phytocompounds

SIMPLE SUMMARY: Lung cancer is the leading cause of mortality in cancer patients, causing an estimated 1.8 million deaths in the year 2020. However, the available therapeutic options exert numerous adverse effects and adequate therapeutic activity is still to be achieved. Therefore, there is a need for the development of safe and effective treatment for lung cancer. Phytochemicals are well documented for their anticancer potential against lung cancer and have a strong rationale for further investigation as a potential chemotherapeutic agent. Notably, phytochemicals act by modulating several signaling pathways, promoting apoptosis, oxidative stress, and disruption of the mitochondrial membrane, inhibiting angiogenesis, and regulating transcription factors. Therefore, an exhaustive and detailed review was carried out to establish the potential role of phytochemicals by conducting a critical analysis of in vitro, in vivo, and clinical evidence in mitigating lung cancer, with emphasis on their impact on signaling pathways. ABSTRACT: Lung cancer is a heterogeneous group of malignancies with high incidence worldwide. It is the most frequently occurring cancer in men and the second most common in women. Due to its frequent diagnosis and variable response to treatment, lung cancer was reported as the top cause of cancer-related deaths worldwide in 2020. Many aberrant signaling cascades are implicated in the pathogenesis of lung cancer, including those involved in apoptosis (B cell lymphoma protein, Bcl-2-associated X protein, first apoptosis signal ligand), growth inhibition (tumor suppressor protein or gene and serine/threonine kinase 11), and growth promotion (epidermal growth factor receptor/proto-oncogenes/phosphatidylinositol-3 kinase). Accordingly, these pathways and their signaling molecules have become promising targets for chemopreventive and chemotherapeutic agents. Recent research provides compelling evidence for the use of plant-based compounds, known collectively as phytochemicals, as anticancer agents. This review discusses major contributing signaling pathways involved in the pathophysiology of lung cancer, as well as currently available treatments and prospective drug candidates. The anticancer potential of naturally occurring bioactive compounds in the context of lung cancer is also discussed, with critical analysis of their mechanistic actions presented by preclinical and clinical studies.