Targeting the Mevalonate Pathway for Treating Lung Cancer

Repurposing of atorvastatin and metformin denotes their individual and combined antiproliferative effects in non-small cell lung cancer

BACKGROUND

Due to the limited success in the treatment of lung adenocarcinomas, new treatment protocols are urgently needed to increase the curability rate and the survival of lung cancer patients.

OBJECTIVES

Although statins, like atorvastatin (Ator), and metformin (Met) are widely accepted as hypolipidemic and hypoglycemic drugs, respectively, there are many predictions about their enhancing antitumor effect when they are combined with traditional chemotherapeutics.

METHODS

The individual and combined antiproliferative potential of Ator and Met was tested by MTT-assay in non-small cell lung cancer (NSCLC) A549 cell line, compared to the corresponding effect of Gemcitabine (Gem) with implication on the mechanisms of action.

RESULTS

Initially, both drugs demonstrated concentration-dependent cytotoxicity in A549 cells. Also, their combination index (CI) indicated their synergistic effect at equi-IC50 concentration (CI = 0.00984). Moreover, Ator and/or Met-treated cells revealed disrupted patterns of SOD, CAT, GSH, MDA, and TAC, developed apoptosis, and larger fractions of the cell population were arrested in G0/G1 phase, particularly in cells dually-treated both Ator and Met. These observations were accompanied by downregulation in the expression of iNOS, HO-1, and the angiogenic marker VEGF, meanwhile, an altered expression of MAPK and AMPK was observed.

CONCLUSION

Conclusively, these data suggest that repurposing of Ator and Met demonstrates their individual and combined antiproliferative effect in non-small cell lung cancer and they may adopt a similar mechanism of action.

A review of Glycogen Synthase Kinase-3 (GSK3) inhibitors for cancers therapies

The intricate molecular pathways governing cancer development and progression have spurred intensive investigations into novel therapeutic targets. Glycogen Synthase Kinase-3 (GSK3), a complex serine/threonine kinase, has emerged as a key player with intricate roles in various cellular processes, including cell proliferation, differentiation, apoptosis, and metabolism. Harnessing GSK3 inhibitors as potential candidates for cancer therapy has garnered significant interest due to their ability to modulate key signalling pathways that drive oncogenesis. The review encompasses a thorough examination of the molecular mechanisms underlying GSK3's involvement in cancer progression, shedding light on its interaction with critical pathways such as Wnt/β-catenin, PI3K/AKT, and NF-κB. Through these interactions, GSK3 exerts influence over tumour growth, invasion, angiogenesis, and metastasis, rendering it an attractive target for therapeutic intervention. The discussion includes preclinical and clinical studies, showcasing the inhibitors efficacy across a spectrum of cancer types, including pancreatic, ovarian, lung, and other malignancies. Insights from recent studies highlight the potential synergistic effects of combining GSK3 inhibitors with conventional chemotherapeutic agents or targeted therapies, opening avenues for innovative combinatorial approaches. This review provides a comprehensive overview of the current state of research surrounding GSK3 inhibitors as promising agents for cancer treatment.

Abnormal lipid synthesis as a therapeutic target for cancer stem cells

Cancer stem cells (CSCs) comprise a subpopulation of cancer cells with stem cell properties, which exhibit the characteristics of high tumorigenicity, self-renewal, and tumor initiation and are associated with the occurrence, metastasis, therapy resistance, and relapse of cancer. Compared with differentiated cells, CSCs have unique metabolic characteristics, and metabolic reprogramming contributes to the self-renewal and maintenance of stem cells. It has been reported that CSCs are highly dependent on lipid metabolism to maintain stemness and satisfy the requirements of biosynthesis and energy metabolism. In this review, we demonstrate that lipid anabolism alterations promote the survival of CSCs, including de novo lipogenesis, lipid desaturation, and cholesterol synthesis. In addition, we also emphasize the molecular mechanism underlying the relationship between lipid synthesis and stem cell survival, the signal trans-duction pathways involved, and the application prospect of lipid synthesis reprogramming in CSC therapy. It is demonstrated that the dependence on lipid synthesis makes targeting of lipid synthesis metabolism a promising therapeutic strategy for eliminating CSCs. Targeting key molecules in lipid synthesis will play an important role in anti-CSC therapy.

CircRNA CircZMYM4 inhibits the growth and metastasis of lung adenocarcinoma via the miR-587/ODAM pathway

Circular RNAs (circRNAs) are known to regulate tumorigenesis. In this study, circRNAs microarray was used to analyze the circRNA expression in lung adenocarcinoma (LUAD) tissues, and CircRNA zinc finger MYM-type containing 4(circZMYM4) was selected for further analysis. In this study, we detected circZMYM4 expression in LUAD specimens and cell lines using RT-PCR. The expression of circZMYM4 was further verified in the GEO datasets and TCGA datasets. Gain-of-function and loss-of-function experiments were used to analyze the effects of circZMYM4 on LUAD in vivo and in vitro. The relationship between miR-587 and circZMYM4 or ODAM was predicted by bioinformatics tools and confirmed using dual-luciferase reporter assays and RNA-pull down. We found that circZMYM4 was distinctly down-regulated in LUAD tissues and cell lines. Functional assays revealed that circZMYM4 overexpression suppressed LUAD cell proliferation, metastasis and suppressed apoptosis, while miR-587 overexpression could weaken these effects. Importantly, circZMYM4 upregulated ODAM expression via sponging miR-587 to suppress LUAD progression. ODAM knockdown could reverse the repressive effect of circZMYM4 overexpression on cell proliferation, migration and invasion abilities. Overall, circZMYM4 regulates the miR-587/ODAM axis to suppress LUAD progression, which may become a potential biomarker and therapeutic target.

Metabolic Changes in Early-Stage Non-Small Cell Lung Cancer Patients after Surgical Resection

Simple Summary

Considerable progress in the treatment of non–small cell lung cancer (NSCLC) has been made possible by large-scale technologies that scan the gene expression in tumor cells. While gene expression is informative, it is the changes to cellular metabolism that directly affect the initiation and the progression of the disease. Altered metabolic processes in cancer include how the tumor cells handle fat, proteins, and sugar, produce energy, divide (grow), or migrate. We have used nuclear magnetic resonance and mass spectrometry to survey and document the metabolic changes in blood and urine samples collected from NSCLC patients before and after their lung tumors were surgically removed. We found several molecular compounds that changed in abundance in the blood or urine after surgery, many of which are related to cancer cell metabolism. Further documentation of these changes in large patient populations will lead to non-invasive ways to screen, diagnose, or monitor disease progression in lung cancer patients.

Abstract

Metabolic alterations in malignant cells play a vital role in tumor initiation, proliferation, and metastasis. Biofluids from patients with non–small cell lung cancer (NSCLC) harbor metabolic biomarkers with potential clinical applications. In this study, we assessed the changes in the metabolic profile of patients with early-stage NSCLC using mass spectrometry and nuclear magnetic resonance spectroscopy before and after surgical resection. A single cohort of 35 patients provided a total of 29 and 32 pairs of urine and serum samples, respectively, pre-and post-surgery. We identified a profile of 48 metabolites that were significantly different pre- and post-surgery: 17 in urine and 31 in serum. A higher proportion of metabolites were upregulated than downregulated post-surgery (p < 0.01); however, the median fold change (FC) was higher for downregulated than upregulated metabolites (p < 0.05). Purines/pyrimidines and proteins had a larger dysregulation than other classes of metabolites (p < 0.05 for each class). Several of the dysregulated metabolites have been previously associated with cancer, including leucyl proline, asymmetric dimethylarginine, isopentenyladenine, fumaric acid (all downregulated post-surgery), as well as N6-methyladenosine and several deoxycholic acid moieties, which were upregulated post-surgery. This study establishes metabolomic analysis of biofluids as a path to non-invasive diagnostics, screening, and monitoring in NSCLC.

Targeting SREBP-2-Regulated Mevalonate Metabolism for Cancer Therapy

Recently, targeting metabolic reprogramming has emerged as a potential therapeutic approach for fighting cancer. Sterol regulatory element binding protein-2 (SREBP-2), a basic helix-loop-helix leucine zipper transcription factor, mainly regulates genes involved in cholesterol biosynthesis and homeostasis. SREBP-2 binds to the sterol regulatory elements (SREs) in the promoters of its target genes and activates the transcription of mevalonate pathway genes, such as HMG-CoA reductase (HMGCR), mevalonate kinase and other key enzymes. In this review, we first summarized the structure of SREBP-2 and its activation and regulation by multiple signaling pathways. We then found that SREBP-2 and its regulated enzymes, including HMGCR, FPPS, SQS, and DHCR4 from the mevalonate pathway, participate in the progression of various cancers, including prostate, breast, lung, and hepatocellular cancer, as potential targets. Importantly, preclinical and clinical research demonstrated that fatostatin, statins, and N-BPs targeting SREBP-2, HMGCR, and FPPS, respectively, alone or in combination with other drugs, have been used for the treatment of different cancers. This review summarizes new insights into the critical role of the SREBP-2-regulated mevalonate pathway for cancer and its potential for targeted cancer therapy.