Antiproliferative and Antimigratory Activity of Poly-gallic Acid in Cancer Cell Lines.

BACKGROUND/AIM: Enzyme-mediated grafting of poly (gallic acid) (PGAL) and L-arginine and a-L-lysine onto PGAL produces reactive oxygen species (ROS)-suppressor multiradical molecules with low cytotoxicity, high thermostability and water solubility with cancer treatment potential. This study examined the anticancer effects of these molecules in hepatic (HepG2, ATCC HB-8065), breast (MCF7, ATCC HTB-22), and prostate (PC-3, ATCC CRL-1435 and DU 145, ATCC HTB-81) cancer cell lines, as well as in fibroblasts from healthy human skin as control cells. MATERIALS AND METHODS: PGAL was synthesized by the oxidative polymerization of the naturally abundant GA using laccase from Trametes versicolor. Insertions of amino acids L-arginine and α-L-lysine on the PGAL chain were carried out by microwave. The cells of dermal fibroblast (Fb) were obtained from primary skin cultures and isolated from skin biopsies. The cancer cells lines of hepatic (HepG2), breast (MCF7), and prostate (PC-3, DU 145) were obtained from ATCC. The viability of the cancer cells and the primary culture was obtained by the MTT assay. Proliferation was demonstrated by crystal violet assay. Cell migration was determined by Wound healing assay. Finally, cell cycle analysis was carried out with cells. RESULTS: The results show that 200 µg/ml of PGAL cultured in vitro with prostate cancer cells decreased viability, proliferation, and migration, as well as arrested cells in the G1 and S phases of the cell cycle. In contrast, the dermal fibroblasts and the hepatic line remained unaffected. The random grafting of L-Arg and a-L-Lys onto the PGAL chain also decreased the viability of prostate cancer cells. CONCLUSION: PGAL and PGAL-grafted amino acids are potential adjuvants for prostate cancer treatment, with improved physicochemical characteristics compared to GA.

LncRNAs-associated to genomic instability: A barrier to cancer therapy effectiveness.

Although a large part of the genome is transcribed, only 1.9% has a protein-coding potential; most of the transcripts are non-coding RNAs such as snRNAs, tRNAs, and rRNAs that participate in mRNA processing and translation. In addition, there are small RNAs with a regulatory role, such as siRNAs, miRNAs, and piRNAs. Finally, the long non-coding RNAs (lncRNAs) are transcripts of more than 200 bp that can positively and negatively regulate gene expression (both in cis and trans), serve as a scaffold for protein recruitment, and control nuclear architecture, among other functions. An essential process regulated by lncRNAs is genome stability. LncRNAs regulate genes associated with DNA repair and chromosome segregation; they are also directly involved in the maintenance of telomeres and have recently been associated with the activity of the centromeres. In cancer, many alterations in lncRNAs have been found to promote genomic instability, which is a hallmark of cancer and is associated with resistance to chemotherapy. In this review, we analyze the most recent findings of lncRNA alterations in cancer, their relevance in genomic instability, and their impact on the resistance of tumor cells to anticancer therapy.

The Roles of Histone Post-Translational Modifications in the Formation and Function of a Mitotic Chromosome.

During mitosis, many cellular structures are organized to segregate the replicated genome to the daughter cells. Chromatin is condensed to shape a mitotic chromosome. A multiprotein complex known as kinetochore is organized on a specific region of each chromosome, the centromere, which is defined by the presence of a histone H3 variant called CENP-A. The cytoskeleton is re-arranged to give rise to the mitotic spindle that binds to kinetochores and leads to the movement of chromosomes. How chromatin regulates different activities during mitosis is not well known. The role of histone post-translational modifications (HPTMs) in mitosis has been recently revealed. Specific HPTMs participate in local compaction during chromosome condensation. On the other hand, HPTMs are involved in CENP-A incorporation in the centromere region, an essential activity to maintain centromere identity. HPTMs also participate in the formation of regulatory protein complexes, such as the chromosomal passenger complex (CPC) and the spindle assembly checkpoint (SAC). Finally, we discuss how HPTMs can be modified by environmental factors and the possible consequences on chromosome segregation and genome stability.

Genotoxicity of Marijuana in Mono-Users.

Marijuana (Cannabis sp.) is among the most recurred controlled substances in the world, and there is a growing tendency to legalize its possession and use; however, the genotoxic effects of marijuana remain under debate. A clear definition of marijuana's genotoxic effects remains obscure by the simultaneous consumption of tobacco and other recreational substances. In order to assess the genotoxic effects of marijuana and to prevent the bias caused by the use of substances other than cannabis, we recruited marijuana users that were sub-divided into three categories: (1) users of marijuana-only (M), (2) users of marijuana and tobacco (M+T), and (3) users of marijuana plus other recreative substances or illicit drugs (M+O), all the groups were compared against a non-user control group. We quantified DNA damage by detection of γH2AX levels and quantification of micronuclei (MN), one of the best-established methods for measuring chromosomal DNA damage. We found increased levels of γH2AX in peripheral blood lymphocytes from the M and M+T groups, and increased levels of MNs in cultures from M+T group. Our results suggest a DNA damage increment for M and M+T groups but the extent of chromosomal damage (revealed here by the presence of MNs and NBuds) might be related to the compounds found in tobacco. We also observed an elevated nuclear division index in all marijuana users in comparison to the control group suggesting a cytostatic dysregulation caused by cannabis use. Our study is the first in Mexico to assess the genotoxicity of marijuana in mono-users and in combination with other illicit drugs.

Mitotic and DNA Damage Response Proteins: Maintaining the Genome Stability and Working for the Common Good.

Cellular function is highly dependent on genomic stability, which is mainly ensured by two cellular mechanisms: the DNA damage response (DDR) and the Spindle Assembly Checkpoint (SAC). The former provides the repair of damaged DNA, and the latter ensures correct chromosome segregation. This review focuses on recently emerging data indicating that the SAC and the DDR proteins function together throughout the cell cycle, suggesting crosstalk between both checkpoints to maintain genome stability.

The enzymatic poly(gallic acid) reduces pro-inflammatory cytokines in vitro, a potential application in inflammatory diseases.

Cytokines like IL-6, TNF-α, and IL-1ß are important mediators of inflammation in many inflammatory diseases, as well as in cellular processes like cell proliferation and cell adhesion. Finding new molecules that decrease cell proliferation, adhesion (inflammatory infiltrate), and pro-inflammatory cytokine release could help in the treatment of many inflammatory diseases. The naturally derived poly(gallic acid) (PGAL), produced enzymatically from gallic acid in aqueous medium, is a non-toxic, thermostable multiradical polyanion that is antioxidant and has potential biomedical uses. Experimental evidence has demonstrated that PGAL reduces pro-inflammatory cytokines, which are the target of some inflammatory diseases. PGAL decreased IL-6, TNF-α, and IL-1ß production in human monocytes exposed to PMA without affecting cell viability. Additionally, PGAL reduced cell proliferation by affecting the transition from the S phase to the G2 phase of the cell cycle. Cell adhesion experiments showed that PMA-induced cell adhesion was diminished with the presence of PGAL, particularly at a concentration of 200 µg/mL. These properties of PGAL show a potential use for treating inflammatory diseases, such as psoriasis or arthritis.

An Overview of Vasculogenic Mimicry in Breast Cancer.

Vasculogenic mimicry (VM) is the formation of vascular channels lacking endothelial cells. These channels are lined by tumor cells with cancer stem cell features, positive for periodic acid-Schiff, and negative for CD31 staining. The term VM was introduced by Maniotis et al. (1), who reported this phenomenon in highly aggressive uveal melanomas; since then, VM has been associated with poor prognosis, tumor aggressiveness, metastasis, and drug resistance in several tumors, including breast cancer. It is proposed that VM and angiogenesis (the de novo formation of blood vessels from the established vasculature by endothelial cells, which is observed in several tumors) rely on some common mechanisms. Furthermore, it is also suggested that VM could constitute a means to circumvent anti-angiogenic treatment in cancer. Therefore, it is important to determinant the factors that dictate the onset of VM. In this review, we describe the current understanding of VM formation in breast cancer, including specific signaling pathways, and cancer stem cells. In addition, we discuss the clinical significance of VM in prognosis and new opportunities of VM as a target for breast cancer therapy.

BUB1 and SURVIVIN proteins are not degraded after a prolonged mitosis and accumulate in the nuclei of HCT116 cells.

Spindle poisons activate the spindle assembly checkpoint and prevent mitotic exit until cells die or override the arrest. Several studies have focused on spindle poison-mediated cell death, but less is known about consequences in cells that survive a mitotic arrest. During mitosis, proteins such as CYCLIN B, SECURIN, BUB1 and SURVIVIN are degraded in order to allow mitotic exit, and these proteins are maintained at low levels in the next interphase. In contrast, exit from a prolonged mitosis depends only on degradation of CYCLIN B; it is not known whether the levels of other proteins decrease or remain high. Here, we analyzed the levels and localization of the BUB1 and SURVIVIN proteins in cells that escaped from a paclitaxel-mediated prolonged mitosis. We compared cells with a short arrest (HCT116 cells) with cells that spent more time in mitosis (HT29 cells) after paclitaxel treatment. BUB1 and SURVIVIN were not degraded and remained localized to the nuclei of HCT116 cells after a mitotic arrest. Moreover, BUB1 nuclear foci were observed; BUB1 did not colocalize with centromere proteins. In HT29 cells, the levels of BUB1 and SURVIVIN decreased during the arrest, and these proteins were not present in cells that reached the next interphase. Using time-lapse imaging, we observed morphological heterogeneity in HCT116 cells that escaped from the arrest; this heterogeneity was due to the cytokinesis-like mechanism by which the cells exited mitosis. Thus, our results show that high levels of BUB1 and SURVIVIN can be maintained after a mitotic arrest, which may promote resistance to cell death.