Differential gene expression in a paclitaxel-resistant clone of a head and neck cancer cell line

IP3R1 dysregulation via mir-200c-3p/SSFA2 axis contributes to taxol resistance in head and neck cancer

Head and neck cancer (HNC) is the sixth most common malignancy worldwide. Although current modalities offer a wide variety of therapy choices, head and neck carcinoma has poor prognosis due to its diagnosis at later stages and development of resistance to current therapeutic tools. In the current study, we aimed at exploring the roles of miR-200c-3p during head and neck carcinogenesis and acquisition of taxol resistance. We analyzed miR-200c-3p levels in HNC clinical samples and cell lines using quantitative real-time polymerase chain reaction and evaluated the effects of differential miR-200c-3p expression on cancer-related cellular phenotypes using in-vitro tools. We identified and characterized a direct target of miR-200c-3p using in-silico tools, luciferase and various in-vitro assays. We investigated potential involvement of miR-200c-3p/SSFA2 axis in taxol resistance in-vitro. We found miR-200c-3p expression as significantly downregulated in both HNC tissues and cells compared to corresponding controls. Ectopic miR-200c-3p expression in HNC cells significantly inhibited cancer-related phenotypes such as viability, clonogenicity, migration, and invasion. We, then, identified SSFA2 as a direct target of miR-200c-3p and demonstrated that overexpression of SSFA2 induced malignant phenotypes in HNC cells. Furthermore, we found reduced miR-200c-3p expression in parallel with overexpression of SSFA2 in taxol resistant HNC cells compared to parental sensitive cells. Both involved in intracellular cytoskeleton remodeling, we found that SSFA2 works collaboratively with IP3R1 to modulate resistance to taxol in HNC cells. When considered collectively, our results showed that miR-200c-3p acts as a tumor suppressor microRNA and targets SSFA2/IP3R1 axis to sensitize HNC cells to taxol.

Proteomic identification of target proteins following Drosha knockdown in cervical cancer

The nuclear microRNA (miRNA) processing enzyme Drosha is upregulated in cervical cancer, and its overexpression is related to an invasive tumour phenotype. However, the mechanisms that underlie this effect remain poorly understood. The aim of this study was to identify the potential targets of Drosha in cervical cancer. Here, we demonstrated that Drosha knockdown (Drosha-KD) inhibited proliferation, colony formation and the migration of cervical cancer cells in vitro. A global upregulation of proteins in Drosha-KD cells was revealed by two-dimensional gel electrophoresis (2-DE). Eighteen proteins were identified by liquid chromatography and tandem mass spectrometry technology (LC-MS/MS) from 21 selected protein spots that exhibited significant alterations in Drosha-KD cells. The majority of the identified proteins have been previously associated with tumour formation. The downregulation of tubulin 5β in Drosha-KD cervical cancer cells was further confirmed by western blotting. Our results suggest that Drosha affects the biological activity of cervical cancer cells by regulating the expression of numerous tumour-associated proteins.

Biomarkers of epithelial-mesenchymal transition in squamous cell carcinoma

An understanding of the process by which tumor cells destroy the basement membrane of the surface epithelium, invade, and metastasize is essential to the development of novel treatment of head and neck squamous cell carcinoma (HNSCC). In recent years, there has been increased interest in the role of epithelial-mesenchymal transition (EMT) in invasion. EMT is a process that describes the development of motile, mesenchymal-like cells from non-motile parent epithelial cells. There are 3 known types of EMT that mediate development, wound healing, and carcinogenesis. This review summarizes studies of known EMT biomarkers in the context of HNSCC progression. The biomarkers discussed come from a wide range of proteins, including cell-surface proteins (E-cadherin, N-cadherin, and Integrins), cytoskeletal proteins (α-Smooth Muscle Actin, Vimentin, and β-catenin), extracellular matrix proteins (Collagens, Fibronectin, and Laminin), and transcription factors (SNAIL1, SNAIL2, TWIST, and LEF-1). Overall, the findings of these studies suggest that EMT mediates HNSCC progression. The mechanistic role of the EMT markers that have been associated with HNSCC should be more clearly defined if new anti-HNSCC therapies to block EMT progression are to be developed.

Inhibitory effect of endostatin combined with paclitaxel-cisplatin on breast cancer in xenograft-bearing mice

In the present study, we aimed to investigate the tumor-inhibiting effects of recombinant human endostatin (rhES) combined with paclitaxel-cisplatin (TP regimen) on human breast cancer in xenograft-bearing nude mice. A total of 24 mice bearing human breast cancer xenografts were administered both rhES and TP, TP alone, rhES alone or saline. The tumor growth inhibition was observed. Serum vascular endothelial growth factor (VEGF) levels and microvessel density (MVD) were determined by ELISA and immunohistochemistry, respectively. Cell apoptosis was detected using terminal deoxynucleotidyl transferase dUTP nick end-labeling (TUNEL) staining. Survival time was observed in another 24 nude mice with the same treatment. MVD expression in the group administered rhES and TP was lower than that in the other groups (P<0.05); serum VEGF levels in the combined drug group were lower compared to the other groups; the apoptotic index increased in the combined drug group. We conclude that the effect of the TP regimen combined with rhES on breast cancer is better than that of the TP regimen alone.

Quantitative trait loci mapping reveals candidate pathways regulating cell cycle duration in Plasmodium falciparum

Background

Elevated parasite biomass in the human red blood cells can lead to increased malaria morbidity. The genes and mechanisms regulating growth and development of Plasmodium falciparum through its erythrocytic cycle are not well understood. We previously showed that strains HB3 and Dd2 diverge in their proliferation rates, and here use quantitative trait loci mapping in 34 progeny from a cross between these parent clones along with integrative bioinformatics to identify genetic loci and candidate genes that control divergences in cell cycle duration.

Results

Genetic mapping of cell cycle duration revealed a four-locus genetic model, including a major genetic effect on chromosome 12, which accounts for 75% of the inherited phenotype variation. These QTL span 165 genes, the majority of which have no predicted function based on homology. We present a method to systematically prioritize candidate genes using the extensive sequence and transcriptional information available for the parent lines. Putative functions were assigned to the prioritized genes based on protein interaction networks and expression eQTL from our earlier study. DNA metabolism or antigenic variation functional categories were enriched among our prioritized candidate genes. Genes were then analyzed to determine if they interact with cyclins or other proteins known to be involved in the regulation of cell cycle.

Conclusions

We show that the divergent proliferation rate between a drug resistant and drug sensitive parent clone is under genetic regulation and is segregating as a complex trait in 34 progeny. We map a major locus along with additional secondary effects, and use the wealth of genome data to identify key candidate genes. Of particular interest are a nucleosome assembly protein (PFL0185c), a Zinc finger transcription factor (PFL0465c) both on chromosome 12 and a ribosomal protein L7Ae-related on chromosome 4 (PFD0960c).

Characterization of ovarian cancer ascites on cell invasion, proliferation, spheroid formation, and gene expression in an in vitro model of epithelial ovarian cancer

At least one third of all cases of epithelial ovarian cancer are associated with the production of ascites, although its effect on tumor cell microenvironment remains poorly understood. This study addresses the effect of the heterologous acellular fraction of ovarian cancer-derived ascites on a cell line (OV-90) derived from the chemotherapy-naïve ovarian cancer patient. Ascites were assayed for their effect on cell invasion, growth, and spheroid formation. When compared to either no serum or 5% serum, ascites fell into one of two categories: stimulatory or inhibitory. RNA from OV-90 cells exposed to selected ascites were arrayed on an Affymetrix HG-U133A GeneChip. A supervised analysis identified a number of differentially expressed genes and quantitative polymerase chain reaction validation based on OV-90 cells exposed to 54 independent ascites demonstrated that stimulatory ascites affected the expression of ISGF3G, TRIB1, MKP1, RGS4, PLEC1, and MOSPD1 genes. In addition, TRIB1 expression was shown to independently correlate with prognosis when its expression was ascertained in an independent set of primary cultures established from ovarian ascites. The data support the validity of the strategy to uncover molecular events that are associated with tumor cell behavior and highlight the impact of ascites on the cellular and molecular parameters of ovarian cancer.

Functional and profiling studies prove that prostate cancer upregulated neuroblastoma thymosin β is the true human homologue of rat thymosin β15

A peptide with a sequence identical to rat thymosin beta(Tb)15 was reported to be upregulated in human prostate cancer. However, in this report we provide evidence that TbNB, initially identified in human neuroblastoma, is the only Tb isoform upregulated in human prostate cancer and that the Tb15 sequence is not present herein. In addition, we demonstrate that human TbNB has a higher affinity for actin in comparison to Tb4 and promotes cell migration. In combination, this experimentally validates TbNB as functional homologue of rat Tb15 in the human organism and clarifies the current composition of the human Tb family.

Antitumor activity of CTFB, a novel anticancer agent, is associated with the down-regulation of nuclear factor-kappaB expression and proteasome activation in head and neck squamous carcinoma cell lines

This study aimed to characterize the antitumor activity of 5-Chloro-N-[2-[2-(4-chloro-phenyl)-3-methyl-butoxy]-5-trifluoromethyl-phenyl]-2-hydroxy-benzamide (CTFB), a novel anticancer agent, in head and neck cancer cell lines, FaDu, SCC-25 and cisplatin-resistant CAL-27. CTFB was generated as a result of an extensive medicinal chemistry effort on a lead compound series discovered in a high-throughput screen for inducers of apoptosis. All cell lines showed significant growth delay in response to CTFB treatment at a concentration of 1 micromol/L with 17.16 +/- 2.08%, 10.92 +/- 1.22%, and 27.03 +/- 1.86% of cells surviving at 120 h in FaDu, CAL-27, and SCC-25, respectively. To define proteins involved in the mechanism of action of CTFB, we determined differences in the proteome profile of cell lines before and after treatment with CTFB using two-dimensional difference gel electrophoresis followed by computational image analysis and mass spectrometry. Eight proteins were found to be regulated by CTFB in all cell lines. All these proteins are involved in cytoskeleton formation and function and/or in cell cycle regulation. We showed that CTFB-induced cell growth delay was accompanied by cell cycle arrest at the G(0)-G(1) phase that was associated with the up-regulation of p21/WAF1 and p27/Kip1 expression and the down-regulation of cyclin D1. Furthermore, we showed that activity of CTFB depended on the down-regulation of nuclear factor-kappaB (NF-kappaB) and NF-kappaB p65 phosphorylated at Ser(536). The level of proteasome activity correlated with the response to CTFB treatment, and the down-regulation of NF-kappaB is accompanied by enhanced proteasome activity in all investigated head and neck cancer cell lines. In this report, we show that CTFB reveals multiple effects that lead to delayed cell growth. Our data suggest that this compound should be studied further in the treatment of head and neck cancer.

Cloning and characterization of 40S ribosomal protein S4 gene from Culex pipiens pallens

The 40S ribosomal protein S4 gene (RPS4) has been cloned from Culex pipiens pallens. An open reading frame (ORF) of 789 bp was found to encode a putative 262 amino acid protein. The deduced amino acid sequence shares 96% and 91% identity with RPS4 genes from Aedes and Anopheles respectively. Transcript expression of RPS4 was determined by real-time PCR in all life stages of deltamethrin-susceptible and -resistant strains. The results demonstrated that this gene is expressed at all developmental stages. Meanwhile, in pupae and adults, RPS4 is overexpressed in deltamethrin-resistant strain than in -susceptible strain. Our data for the first time suggests that increased expression of the RPS4 gene may play some role in the development of deltamethrin resistance in C. pipiens pallens.