Genetic Editing and Pharmacogenetics in Current And Future Therapy Of Neurocognitive Disorders

Dementia is an important issue in western societies, and in the following years, this problem will also rise in the developing regions, such as Africa and Asia. The most common types of dementia in adults are Alzheimer's Disease (AD), Dementia with Lewy Bodies (DLB), Frontotemporal Dementia (FTD) and Vascular Dementia (VaD), of which, AD accounts for more than half of the cases. The most prominent symptom of AD is cognitive impairment, currently treated with four drugs: Donepezil, rivastigmine, and galantamine, enhancing cholinergic transmission; as well as memantine, protecting neurons against glutamate excitotoxicity. Despite ongoing efforts, no new drugs in the treatment of AD have been registered for the last ten years, thus multiple studies have been conducted on genetic factors affecting the efficacy of antidementia pharmacotherapy. The researchers investigate the effects of variants in multiple genes, such as ABCB1, ACE, CHAT, CHRNA7, CYP2C9, CYP2C19, CYP2D6, CYP3A4, CYP3A5, CYP3A7, NR1I2, NR1I3, POR, PPAR, RXR, SLC22A1/2/5, SLC47A1, UGT1A6, UGT1A9 and UGT2B7, associated with numerous pathways: the development of pathological proteins, formation and metabolism of acetylcholine, transport, metabolism and excretion of antidementia drugs and transcription factors regulating the expression of genes responsible for metabolism and transport of drugs. The most promising results have been demonstrated for APOE E4, dementia risk variant, BCHE-K, reduced butyrylcholinesterase activity variant, and CYP2D6 UM, ultrarapid hepatic metabolism. Further studies investigate the possibilities of the development of emerging drugs or genetic editing by CRISPR/Cas9 for causative treatment. In conclusion, the pharmacogenetic studies on dementia diseases may improve the efficacy of pharmacotherapy in some patients with beneficial genetic variants, at the same time, identifying the carriers of unfavorable alleles, the potential group of novel approaches to the treatment and prevention of dementia.

Effect of 3-O-acetylaleuritolic acid from in vitro-cultured Drosera spatulata on cancer cells survival and migration

BACKGROUND

Drosera spatulata is a source of many compounds such as naphthoquinones, phenolic acids, flavonoids, anthocyanins, and naphthalene derivatives. Unfortunately, the information regarding the biological activity and chemical profile of those compounds is still incomplete. Herein, we investigated the biological activity of 3-O-acetylaleuritolic acid (3-O-AAA) in cancer cell lines.

METHODS

The cell viability of HeLa, HT-29, MCF7, and MCF12A cells was assessed using MTT assay. Proliferation potential was assessed using the clonogenic assay and flow cytometry. Migration modulation was tested using a scratch assay. Protein expression was analyzed by immunoblotting.

RESULTS

3-O-AAA significantly inhibited the growth of all tested tumor cells. The results of the colony formation assay suggested cytostatic properties of the studied compound. The scratch assay showed that 3-O-AAA was an efficient migration inhibitor in a dose-dependent manner. Moreover, it caused modulation of mTOR, beclin1, and Atg5 proteins suggesting a possible role of the compound in autophagy induction.

CONCLUSION

Collectively, these results demonstrated that 3-O-AAA inhibited the proliferation and migration of cancer cell lines as well as contributed to autophagy induction showing some anticancer properties.

Autophagy as a Potential Therapeutic Target in Breast Cancer Treatment

One of the crucial reasons of breast cancer therapy failure is an impairment of mechanisms responsible for metabolism and cellular homeostasis, which makes it difficult to foresee the response to the treatment. Targeted therapy in breast cancer is dictated by the expression of specific molecules such as growth factor or hormone receptors. Many types of breast cancer exhibit different abnormalities in the apoptotic pathway, which confer the resistance to many forms of chemotherapy. Because of the fundamental importance of autophagy in the development and progression of cancer and its ability to affect treatment response, there has been an immense research on molecular regulation and signal transduction mechanisms that control this process. Here, we summarize the present knowledge concerning different breast cancer treatment strategies using drugs approved for the treatment of different breast cancer molecular subtypes with targeting pathways and factors associated with autophagy modulation/ regulation.

Impact of PKCε downregulation on autophagy in glioblastoma cells

Background

Several efforts have been focused on identification of pathways involved in malignancy, progression, and response to treatment in Glioblastoma (GB). Overexpression of PKCε was detected in histological samples from GB, anaplastic astrocytoma, and gliosarcoma and is considered an important marker of negative disease outcome. In multiple studies on GB, autophagy has been shown as a survival mechanism during cellular stress, contributing to resistance against anti-cancer agents. The main object of this research was to determine the influence of PKCε downregulation on the expression of genes involved in autophagy pathways in glioblastoma cell lines U-138 MG and U-118 MG with high PKCε level.

Methods

We conducted siRNA-mediated knockdown of PKCε in glioblastoma cell lines and studied the effects of autophagy pathway. The expression of autophagy-related genes was analyzed using qPCR and Western blot analysis was carried out to assess protein levels. Immunostaining was used to detect functional autophagic maturation process.

Results

We found that these cell lines exhibited a high basal expression of autophagy-related genes. Our results suggest that the loss of PKCε contributes to the downregulation of genes involved in autophagy pathways. Moreover, most of the changes we observed in Western blot analysis and endogenous immunofluorescence experiments confirmed dysfunction of autophagy programs. We found that knockdown of PKCε induced a decrease in the expression of Beclin1, Atg5, PI3K, whereas the expression of other autophagy-related proteins mTOR and Bcl2 was increased. Treatment of control siRNA glioma cells with rapamycin-induced autophagosome formation and increase in LC3-II level and caused a decrease in the expression of p62. Additionally, PKCε siRNA caused a diminution in the Akt phosphorylation at Ser473 and in the protein level in both cell lines. Moreover, we observed reduction in the adhesion of glioblastoma cells, accompanied by the decrease in total FAK protein level and phosphorylation.

Conclusions

Effects of down-regulation of PKCε in glioma cells raised the possibility that the expression of PKCε is essential for the autophagic signal transduction pathways in these cells.

Thus, our results identify an important role of PKCε in autophagy and may, more importantly, identifyit as a novel therapeutic target.

Zapotin (5,6,2',6'-tetramethoxyflavone) Modulates the Crosstalk Between Autophagy and Apoptosis Pathways in Cancer Cells with Overexpressed Constitutively Active PKCϵ

Autophagy is important in the regulation of survival and death signaling pathways in cancer. PKCϵ revealed high transforming potential and the ability to increase cell migration, invasion, and metastasis. Zapotin (5,6,2',6'-tetramethoxyflavone), a natural flavonoid, showed chemopreventive and anticancer properties. Previously, we reported that downmodulation of induced PKCϵ level by zapotin was associated with decreased migration and increased apoptosis in HeLa cell line containing doxycycline-inducible constitutively active PKCϵ (PKCϵA/E, Ala(159) → Glu). Depending on the genetic and environmental content of cells, autophagy may either precede apoptosis or occur simultaneously. The purpose of this study was to assess the effect of zapotin on autophagy. Increasing concentration of zapotin (from 7.5 µM to 30 µM) caused an inhibition of the formation of autophagosomes and a decline in microtubule-associated protein 1 light chain 3 (LC3) protein levels. The gene expression level of major negative regulator of autophagy was noticeably increased. Moreover, the expression of the pivotal autophagy genes was decreased. These changes were accompanied by alternation in autophagy-related protein levels. In conclusion, our results implied that both the antiautophagic and the proapoptosis effect of zapotin in HeLaPKCϵA/E cells are associated with the protein kinase C epsilon signaling pathway and lead to programmed cell death.

Beclin-1 and its role as a target for anticancer therapy

The Nomenclature Committee on Cell Death (NCCD, 2009) defines different types of cell death on the basis of morphological, enzymological, immunological and functional criteria. Four basic types of cell death are distinguished from the biochemical point of view: necrosis, apoptosis, autophagy and cornification. Autophagy (macroautophagy) is a highly conserved process by which defective organelles, non-functional proteins and lipids become sequestered within structures called autophagosomes, which fuse with lysosomes, and the engulfed components are then degraded by lysosomal enzymes. The role of autophagy is not only the elimination of components, it also serves as a dynamic recycling system that produces new materials and energy for cellular renovation and homeostasis. Beclin-1 is a protein that plays a central role in autophagy; it interacts with multiple cofactors (Atg14L, UVRAG, Bif-1, Rubicon, Ambra1, HMGB1, IP3R, PINK and survivin) to promote the formation of the Beclin-1-Vps34-Vps15 complex which triggers the autophagy protein cascade. Beclin-1 dysfunction may lead to immune disorders, liver and neurodegenerative diseases as well as cancer. A positive and negative correlation between the expression pattern and/or activity of Beclin-1 and carcinogenesis has been demonstrated. Here we describe recent advances in understanding the molecular dynamics and regulation of autophagy and we discuss Beclin-1's contribution to anticancer therapy.

Evaluation of apoptotic activity of new condensed pyrazole derivatives

Cyclic pyrazoles exhibit cytotoxicity to human cancer cells through apoptosis induction. We investigated the proapoptotic activities of two novel synthetic pyrazoles: 5-(p-toluenesulfonyl)pyrazolo[4,3-f]quinoline (tospyrquin) and 5-chloro-3-(p-toluenesulfonyl)indazole (tosind) in HT29 colon cancer cells which are characterised by point mutation (G/A in codon 273) in the p53 gene, which causes the lack of functionality of the p53 protein. Cell viability was evaluated in the MTT assay, cell morphology was assessed by DAPI staining, flow cytometry was used to study the cell cycle, Western blot techniques were applied for measurements of the Bax, Bcl-2, caspase-8, caspase-9 and PARP-1 proteins and DNA damage was evaluated in the Comet assay. Tospyrquin or tosind in a concentration range of 2.5 μM-15 μM caused an approximately 20% diminishment in cell growth, but in higher concentrations (25-100 μM) the observed effect depended on the pyrazole structure and time of treatment. In cell cycle analysis, tosind caused 23.7% of apoptotic death and tospyrquin - 14.9%. These data were supported by an increased level of the pro-apoptotic protein Bax, a decreased level of the anti-apoptotic Bcl-2 and enhanced caspase-8, caspase-9, PARP-1 cleavage. DNA damage was dose-dependent for both tested compounds. The results suggest that the pro-apoptotic activity of tospyrquin and tosind is probably regulated by the extrinsic and the intrinsic pathways.

The tetramethoxyflavone zapotin selectively activates protein kinase C epsilon, leading to its down-modulation accompanied by Bcl-2, c-Jun and c-Fos decrease

Zapotin, a tetramethoxyflavone, is a natural compound with a wide spectrum of activities in neoplastic cells. Protein kinase C epsilon (PKCε) has been shown to be oncogenic, with the ability to increase cell migration, invasion and survival of tumor cells. Here we report that zapotin inhibits cell proliferation. In wild-type HeLa cells with basal endogenous expression of PKCε, the IC(50) was found to be 17.9 ± 1.6 μM. In HeLa cells overexpressing doxycycline-inducible constitutively active PKCε (HeLaPKCεA/E), the IC(50) was 7.6 ± 1.3 μM, suggesting that PKCε enhances the anti-proliferative effect of zapotin. Moreover, we found that zapotin selectively activated PKCε in comparison with other PKC family members, but attenuated doxycycline-induced PKCε expression. As a result of zapotin treatment for 6, 12 and 24h, the doxycycline-induced levels of the two differently phosphorylated PKCε forms (87 kDa and 95 kDa) were decreased. Migration assays revealed that increasing concentrations of zapotin (from 3.5 to 15 μM) decreased migration of HeLaPKCεA/E cells. Furthermore, zapotin significantly increased the fraction of apoptotic cells in doxycycline-induced (HeLaPKCεA/E) cells after 24h and decreased the levels of Bcl-2, c-Jun, c-Fos. This was accompanied by a degradation of PARP-1. In summary, activation of PKCε and down-modulation of the induced PKCε level by zapotin were associated with decreased migration and increased apoptosis. These observations are consistent with the previously reported chemopreventive and chemotherapeutic action of zapotin.