Deciphering the Mechanism of Action Involved in Enhanced Suicide Gene Colon Cancer Cell Killer Effect Mediated by Gef and Apoptin

Abstract

Despite the great advances in cancer treatment, colorectal cancer has emerged as the second highest cause of death from cancer worldwide. For this type of tumor, the use of suicide gene therapy could represent a novel therapy. We recently demonstrated that co-expression of gef and apoptin dramatically inhibits proliferation of the DLD-1 colon cell line. In the present manuscript, we try to establish the mechanism underlying the enhanced induction of apoptosis by triggering both gef and apoptin expression in colon tumor cells. Scanning microscopy reveals that simultaneous expression of gef and apoptin induces the apparition of many “pores” in the cytoplasmic membrane not detected in control cell lines. The formation of pores induced by the gef gene and accentuated by apoptin results in cell death by necrosis. Moreover, we observed the presence of apoptotic cells. Performing protein expression analysis using western blot, we revealed an activation of mitochondrial apoptosis (increased expression of Pp53, cytochrome c, Bax, and caspase 9) and also the involvement of the extrinsic pathway through caspase 8activation. In conclusion, in this manuscript we demonstrate for the first time that the extrinsic pathway of apoptosis and pore formation is also involved in the cell death caused by the co-expression of the gef and apoptin genes. Our results suggest that co-expression of gef and apoptin genes induces an increase in post-apoptotic necrotic cell death and could be a valuable tool in the design of new antitumor strategies focused on the enhancement of the immune response against cancer cell death.

Cancer Treatment Goes Viral: Using Viral Proteins to Induce Tumour-Specific Cell Death

“…Notably, caspase 3 is activated during the overexpression of E4orf4 in cancer cells but doesn't seem to be vital for the induction of cell death [97]. Other caspases 9 and 7 are also significant for CAV-Apoptin and NS1 induced cell death [92][93][94]102].…”

“…The initiation of mitochondrial cell death by means of mitochondrial outer membrane permeabilization (MOMP) is a universal effect of these viral proteins. The pro-apoptotic proteins targeting the mitochondria Bax and Bak are important in Apoptin cancer toxicity as treatment with Apoptin increased the expression of Bax and cells devoid of both are strongly protected against cell death [92,102]. Moreover, studies have presented that Apoptin treatment leads to a loss of mitochondria membrane potential and subsequent release of cytochrome c [92,102,103].…”

“…The pro-apoptotic proteins targeting the mitochondria Bax and Bak are important in Apoptin cancer toxicity as treatment with Apoptin increased the expression of Bax and cells devoid of both are strongly protected against cell death [92,102]. Moreover, studies have presented that Apoptin treatment leads to a loss of mitochondria membrane potential and subsequent release of cytochrome c [92,102,103]. Similarly, the highly related HGV-Apoptin protein also relies on the activity of Bax and Bak, as jurkat cells that lack expression are protected from apoptosis.…”

Cetuximab-Conjugated Perfluorohexane/Gold Nanoparticles for Low Intensity Focused Ultrasound Diagnosis Ablation of Thyroid Cancer Treatment

“…The Food and Drug Administration (FDA) has approvedpreclinical treatments using cetuximab for the treatment of neckand head carcinoma and colorectal carcinoma with EGFR-expressingcancer tumors. This C225 might be a suitable objective for thestructure of nanocarriers to improve the outcome of ATC therapy.Remarkably, some researchers have revealed that for a wide spectrumof cancers, the blend of C225 with CPT-11 equivalents such asPer uorohexane/Gold Nanoparticles (Au-PFH-NPs) has signi cantsynergetic antitumor effects [22][23][24][25], thus, enhancing ATCdiagnostics. However, owing to the reduced vascular dispersal ofC225 and the hydrophobicity of the Au-PFH-NPs, the nanoparticles'(NPs) penetrability in the growth and their quantity in the tumorarea were inherently imperfect, which greatly debilitated theiranticancer e cacy.…”

Colorectal Cancer Research: Basic, Preclinical, and Clinical Approaches

“…It has become evident that further efforts in colorectal cancer research are required, from providing a better understanding of the cellular and molecular mechanisms leading to colorectal neoplasm initiation and progression from adenoma to metastasis, to generating reliable non-invasive detection tests for identifying lesions at early stages, as well as refining the current therapeutic and personalized approaches and developing new ones. The aim of this Special Issue is to cover all aspects of colorectal cancer research, including basic, preclinical, and clinical approaches.The original articles of this Special Issue present innovative findings toward the design of new strategies that may contribute to the fight against colorectal cancer cells, such as treatments that enhance apoptosis-related mechanisms [1,2], chemosensitivity [3-6] and/or radiotherapy [7], and the characterization of new pathways that lead to the identification of specific biomarkers and/or decipher unique mechanisms underlying colorectal cancer initiation and progression. These mechanisms include the transcriptional regulation of DNA repair proteins [8]; the epigenetic regulation of the zinc finger E-box-binding homeobox 1 [9] and the expression of the (pro)renin receptor [10], , and calcium and calcium-activated potassium channels [12]; the contribution of immune cells in the tumor microenvironment [13]; and the identification of genetic aberrations that occur during the transition from adenoma to carcinoma [14].…”