Next-generation multimodality of nutrigenomic cancer therapy: sulforaphane in combination with acetazolamide actively target bronchial carcinoid cancer in disabling the PI3K/Akt/mTOR survival pathway and inducing apoptosis.

Reza Bayat Mokhtari,Myron R Szewczuk,Albina Tyker,Hai-Ling Margaret Cheng,Bikul Das,Narges Baluch,Federico Pio Fabrizio,Sushil Kumar,Angelo Sparaneo,Bessi Qorri,Herman Yeger,Lucia Anna Muscarella

doi:10.18632/oncotarget.28011

Abstract

Objective: Aberrations in the PI3K/AKT/mTOR survival pathway in many cancers are the most common genomic abnormalities. The phytochemical and bioactive agent sulforaphane (SFN) has nutrigenomic potential in activating the expression of several cellular protective genes via the transcription factor nuclear factor erythroid 2-related factor 2 (Nrf2). Nrf2 is primarily related to mechanisms of endogenous cellular defense and survival. The efficacy of SFN in combination with acetazolamide (AZ) was investigated in reducing typical H727 and atypical H720 BC survival, migration potential, and apoptosis in vitro and in vivo preclinical xenograft tissues.Materials and Methods: Microscopic imaging, immunocytochemistry, wound healing assay, caspase-cleaved cytokeratin 18 (M30, CCK18) CytoDeath ELISA assay, immunofluorescence labeling assays for apoptosis, hypoxia, Western Blotting, Tunnel assay, measurement of 5-HT secretion by carbon fiber amperometry assay, quantitative methylation-specific PCR (qMSP), morphologic changes, cell viability, apoptosis activity and the expression levels of phospho-Akt1, Akt1, HIF-1α, PI3K, p21, CAIX, 5-HT, phospho-mTOR, and mTOR in xenografts derived from typical H727 and atypical H720 BC cell lines.Results: Combining AZ+SFN reduced tumor cell survival compared to each agent alone, both in vitro and in vivo xenograft tissues. AZ+SFN targeted multiple pathways involved in cell cycle, serotonin secretion, survival, and growth pathways, highlighting its therapeutic approach. Both H727 and H720 cells were associated with induction of apoptosis, upregulation of the p21 cell cycle inhibitor, and downregulation of the PI3K/Akt/mTOR pathway, suggesting that the PI3K/Akt/mTOR pathway is a primary target of the AZ+SFN combination therapy.Conclusions: Combining SFN+AZ significantly inhibits the PI3K/Akt/mTOR pathway and significantly reducing 5-HT secretion in carcinoid syndrome.

Highlights

Malignant cells are characterized by the upregulation and activation of many survival signaling pathways involved in proliferation, apoptosis, invasion, and angiogenesis [1]
We investigated the mechanism(s) by which SFN combined with AZ exerts its nutrigenetic therapeutic effect on bronchial carcinoid (BC) cell lines and in BC xenograft tissues derived from H727 and H720 BC cells previously developed in NOD/SCID mice
These findings demonstrate that SFN combined with AZ supports the nutrigenetic therapeutics of SFN in suppressing the migratory/invasive potential of typical bronchial carcinoids

Summary

Introduction

Malignant cells are characterized by the upregulation and activation of many survival signaling pathways involved in proliferation, apoptosis, invasion, and angiogenesis [1]. Neuroendocrine tumors (NETs) are malignant neoplasms derived from the neuroendocrine cells of primitive foregut, midgut, and hindgut structures. In the lung, these neoplasms are classified into high-grade carcinomas and low-grade bronchial carcinoids (BCs). The phosphatidylinositol 3-Kinase-Akt (PI3K-Akt) pathway is one of the critical cancer pathogenic pathways with widespread downstream effects involving cell cycle survival and hypoxic metabolic response, angiogenesis, and metastasis [5]. Further downstream activation of the Akt/NF-kB pathway can inactivate apoptotic pathways and promote the transcription of numerous pro-survival genes, including those responsible for angiogenesis [8]. As the PI3K-Akt pathway is overactive in many cancers, including non-small cell lung cancer, it is another potential therapeutic target in BC [9]

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Conclusion