Protein expression profile using two-dimensional gel analysis in squamous cervical cancer patients

Understanding Cervical Cancer through Proteomics

Cancer is one of the leading public health issues worldwide, and the number of cancer patients increases every day. Particularly, cervical cancer (CC) is still the second leading cause of cancer death in women from developing countries. Thus, it is essential to deepen our knowledge about the molecular pathogenesis of CC and propose new therapeutic targets and new methods to diagnose this disease in its early stages. Differential expression analysis using high-throughput techniques applied to biological samples allows determining the physiological state of normal cells and the changes produced by cancer development. The cluster of differential molecular profiles in the genome, the transcriptome, or the proteome is analyzed in the disease, and it is called the molecular signature of cancer. Proteomic analysis of biological samples of patients with different grades of cervical intraepithelial neoplasia (CIN) and CC has served to elucidate the pathways involved in the development and progression of cancer and identify cervical proteins associated with CC. However, several cervical carcinogenesis mechanisms are still unclear. Detecting pathologies in their earliest stages can significantly improve a patient's survival rate, prognosis, and recurrence. The present review is an update on the proteomic study of CC.

Annexin A1 peptide and endothelial cell-conditioned medium modulate cervical tumorigenesis

Cervical cancer is one of the leading causes of cancer death in women worldwide, and its tumorigenesis can be influenced by the microenvironment. The anti-inflammatory protein annexin A1 (ANXA1) has been reported to be associated with cancer progression and metastasis, suggesting that it plays a role in regulating tumour cell proliferation. Here, we examined the effect of the N-terminal peptide Ac2-26 of ANXA1 on the HaCaT cell line (normal) and HeLa cell line (cervical cancer) co-cultured with endothelium cell-conditioned medium (HMC). Treatment with Ac2-26 decreased proliferation and increased motility of cervical cancer cells, but did not affect cellular morphology or viability. Combined HMC stimulus and Ac2-26 treatment resulted in an increase in apoptotic HeLa cells, upregulated expression of MMP2, and downregulated expression of COX2,EP3 and EP4. In conclusion, Ac2-26 treatment may modulate cellular and molecular mechanisms underlying cervical carcinogenesis.

Assessment of cellular and serum proteome from tongue squamous cell carcinoma patient lacking addictive proclivities for tobacco, betel nut, and alcohol: Case study

The intriguing molecular pathways involved in oral carcinogenesis are still ambiguous. The oral squamous cell carcinoma (OSCC) ranks as the most common type constituting more than 90% of the globally diagnosed oral cancers cases. The elevation in the OSCC incidence rate during past 10 years has an alarming impression on human healthcare. The major challenges associated with OSCC include delayed diagnosis, high metastatic rates, and low 5-year survival rates. The present work foundations on reverse genetic strategy and involves the identification of genes showing expressional variability in an OSCC case lacking addictive proclivities for tobacco, betel nut, and/or alcohol, major etiologies. The expression modulations in the identified genes were analyzed in 16 patients comprising oral pre-cancer and cancer histo-pathologies. The genes SCCA1 and KRT1 were found to down regulate while DNAJC13, GIPC2, MRPL17, IG-Vreg, SSFA2, and UPF0415 upregulated in the oral pre-cancer and cancer pathologies, implicating the genes as crucial players in oral carcinogenesis.

iTRAQ-based quantitative proteomic analysis of cervical cancer

Cervical cancer is the seventh most common cancer overall and the third among females. To obtain systematic insight into the protein profile that participates in cervical tumor oncogenesis and improve the current target therapies, iTRAQ labeling and NanoLC-MS/MS analysis were utilized to detect differentially expressed proteins in cervical cancer. As a result, 3,647 proteins were identified, among which the expression levels of 294 proteins in cervical cancer samples were distinct from the paired non-tumor samples. Further validation of the differentially expressed proteins, including G6PD, ALDH3A1, STAT1 and HSPB1, was carried out via qRT-PCR, western blot analysis and tissue microarray. Functional analysis of one of the highly expressed proteins, G6PD, was performed using RNA interference. Attenuated G6PD expression reduced the capacity of HeLa cells to migrate and invade in vitro. Our investigation complemented the understanding of cervical cancer progression. Furthermore, the present study supports the notion that suppressing the expression of G6PD may be a promising strategy in developing novel cancer therapeutic drugs.

Pro-oncogenic function of HIP-55/Drebrin-like (DBNL) through Ser269/Thr291-phospho-sensor motifs

HIP-55 (HPK1-interacting protein of 55 kDa, also named DBNL, SH3P7, and mAbp1) is a multidomain adaptor protein that is critical for organ development and the immune response. Here, we report the coupling of HIP-55 to cell growth control through its 14-3-3-binding phospho-Ser/Thr-sensor sites. Using affinity chromatography, we found HIP-55 formed a complex with 14-3-3 proteins, revealing a new node in phospho-Ser/Thr-mediated signaling networks. In addition, we demonstrated that HIP-55 is required for proper cell growth control. Enforced HIP-55 expression promoted proliferation, colony formation, migration, and invasion of lung cancer cells while silencing of HIP-55 reversed these effects. Importantly, HIP-55 was found to be upregulated in lung cancer cell lines and in tumor tissues of lung cancer patients. Upregulated HIP-55 was required to promote the growth of tumors in a xenograft animal model. However, tumors with S269A/T291A-mutated HIP-55, which ablates 14-3-3 binding, exhibited significantly reduced sizes, supporting a vital role of the HIP-55/14-3-3 protein interaction node in transmitting oncogenic signals. Mechanistically, HIP-55-mediated tumorigenesis activity appears to be in part mediated by antagonizing the tumor suppressor function of HPK1. Thus, the HIP-55–mediated oncogenic pathway, through S269/T291, may be exploited for the development of new therapeutic strategies.

Differential expression analysis of Golgi apparatus proteomes in hepatocellular carcinomas and the surrounding liver tissues

AIM

Hepatocellular carcinoma (HCC) is the sixth most common malignancy worldwide. Liver is the largest human digestive gland with abundant Golgi apparatus involved in cell division, migration and apoptosis and others.

METHODS

In the present study, Golgi apparatus of HCC and the surrounding liver tissues were isolated by sucrose density gradient centrifugation and identified by electron microscopy and enzymology methods. Using 2-D gel electrophoresis and mass spectrometry, 17 differentially expressed protein of Golgi apparatus in HCC and the surrounding liver tissue were screened and identified in the Mascot database.

RESULTS

Of those differentially expressed proteins, six were upregulated and 11 were downregulated, some of them were related to the biological processes such as protein sorting, glycosylation, cell cycle regulation, transcription regulation and Golgi integrity. One protein, annexin A5, was verified to be upregulated in HCC by western blot.

CONCLUSION

The differentially expressed proteins may provide new insight into HCC biology and potential diagnostic and therapeutic biomarkers.

Annexin A5 protein expression is associated with the histological differentiation of uterine cervical squamous cell carcinoma in patients with an increased serum concentration

Annexin A5 (ANXA5) is a calcium-dependent phospholipid-binding protein belonging to the annexin family and is expressed abnormally in several types of carcinoma. In the present study, ANXA5 protein expression was evaluated by western blot analysis in a series of 60 human uterine cervical squamous cell carcinomas (UCSCCs) to search for molecular alterations that may be able to serve as useful diagnostic/prognostic markers. The upregulation of ANXA5 expression was observed in 48/60 UCSCC cases (80%), whereas a weak expression was observed in the 25 normal uterine cervical tissues. ANXA5 expression was also analyzed by immunohistochemical staining, western blot and reverse transcription-polymerase chain reaction (RT-PCR) assays of the UCSCC and uterine cervical normal tissue lesions. All dysplastic tissues showed significantly increased ANXA5 expression compared with the weak signal observed in normal epithelia. A close association was observed between the ANXA5 expression levels and the histological grade of UCSCC. Compared with moderately and well-differentiated tumors, there was a significant increase in ANXA5 expression in poorly differentiated tumors. Furthermore, ANXA5 concentrations in the blood serum of the patients were significantly increased. Our findings clearly identify ANXA5 as an effective differentiation marker for the histopathological grading of UCSCCs and for the detection of epithelial dysplasia. The results from our study support the critical role of ANXA5 in the molecular profiling of UCSCC.

Altered carcinogenesis and proteome in mammary glands of rats after prepubertal exposures to the hormonally active chemicals bisphenol a and genistein

Through our diet, we are exposed to numerous natural and man-made chemicals, including polyphenols with hormone-like properties. The most abundant hormonally active polyphenols are characterized as weak estrogens. These chemicals are hypothesized to interfere with signaling pathways involved in important diseases such as breast cancer, which in most cases is initially estrogen dependent. Two such chemicals are bisphenol A (BPA), a plasticizer, and genistein, a component of soy. In spite of both possessing estrogenic properties, BPA and genistein yield different health outcomes. The exposure of rats during the prepubertal period to BPA increases the susceptibility of adult animals for mammary cancer development, whereas genistein decreases this susceptibility in a chemically induced model. Because both BPA and genistein possess estrogenic properties, it is certainly plausible that additional mechanisms are affected by these chemicals. Hence, it was our goal to investigate at the protein level how exposure to these 2 chemicals can contribute to mammary cancer causation as opposed to cancer chemoprevention. Using 2-dimensional gel electrophoresis followed by MS analysis, we identified differentially regulated proteins from the mammary glands of rats prepubertally exposed to BPA and genistein. Following protein identification, we used immunoblotting techniques to validate the identity and regulation of these proteins and to identify downstream signaling proteins. Our studies highlight the importance of proteomics technology in elucidating signaling pathways altered by exposure to hormonally active chemicals and its potential value in identifying biomarkers for mammary cancer.

Modeling microRNA-mRNA interactions using PLS regression in human colon cancer

Background

Changes in microRNA (miRNA) expression patterns have been extensively characterized in several cancers, including human colon cancer. However, how these miRNAs and their putative mRNA targets contribute to the etiology of cancer is poorly understood. In this work, a bioinformatics computational approach with miRNA and mRNA expression data was used to identify the putative targets of miRNAs and to construct association networks between miRNAs and mRNAs to gain some insights into the underlined molecular mechanisms of human colon cancer.

Method

The miRNA and mRNA microarray expression profiles from the same tissues including 7 human colon tumor tissues and 4 normal tissues, collected by the Broad Institute, were used to identify significant associations between miRNA and mRNA. We applied the partial least square (PLS) regression method and bootstrap based statistical tests to the joint expression profiles of differentially expressed miRNAs and mRNAs. From this analysis, we predicted putative miRNA targets and association networks between miRNAs and mRNAs. Pathway analysis was employed to identify biological processes related to these miRNAs and their associated predicted mRNA targets.

Results

Most significantly associated up-regulated mRNAs with a down-regulated miRNA identified by the proposed methodology were considered to be the miRNA targets. On average, approximately 16.5% and 11.0% of targets predicted by this approach were also predicted as targets by the common prediction algorithms TargetScan and miRanda, respectively. We demonstrated that our method detects more targets than a simple correlation based association. Integrative mRNA:miRNA predictive networks from our analysis were constructed with the aid of Cytoscape software. Pathway analysis validated the miRNAs through their predicted targets that may be involved in cancer-associated biological networks.

Conclusion

We have identified an alternative bioinformatics approach for predicting miRNA targets in human colon cancer and for reverse engineering the miRNA:mRNA network using inversely related mRNA and miRNA joint expression profiles. We demonstrated the superiority of our predictive method compared to the correlation based target prediction algorithm through a simulation study. We anticipate that the unique miRNA targets predicted by the proposed method will advance the understanding of the molecular mechanism of colon cancer and will suggest novel therapeutic targets after further experimental validations.

α-Enolase: a promising therapeutic and diagnostic tumor target

α-enolase (ENOA) is a metabolic enzyme involved in the synthesis of pyruvate. It also acts as a plasminogen receptor and thus mediates activation of plasmin and extracellular matrix degradation. In tumor cells, ΕΝΟΑ is upregulated and supports anaerobic proliferation (Warburg effect), it is expressed at the cell surface, where it promotes cancer invasion, and is subjected to a specific array of post-translational modifications, namely acetylation, methylation and phosphorylation. Both ENOA overexpression and its post-translational modifications could be of diagnostic and prognostic value in cancer. This review will discuss recent information on the biochemical, proteomics and immunological characterization of ENOA, particularly its ability to trigger a specific humoral and cellular immune response. In our opinion, this information can pave the way for effective new therapeutic and diagnostic strategies to counteract the growth of the most aggressive human disease.

Use of cervicovaginal fluid for the identification of biomarkers for pathologies of the female genital tract

Cervicovaginal fluid has an important function in the homeostasis and immunity of the lower female genital tract. Analysis of the cervicovaginal fluid proteome may therefore yield important information about the pathogenesis of numerous gynecological pathologies. Additionally, cervicovaginal fluid has great potential as a source of biomarkers for these conditions.

This review provides a detailed discussion about the human cervicovaginal proteome and the proteomics studies performed to characterize this biological fluid. Furthermore, infection-correlated pathological conditions of the female genital tract are discussed for which cervicovaginal fluid has been used in order to identify potential biomarkers. Recent years, numerous studies have analyzed cervicovaginal fluid samples utilizing antibody-based technologies, such as ELISA or Western blotting, to identify biomarkers for preterm birth, premature preterm rupture of membranes, bacterial vaginosis and cervical cancer. The present article will discuss the importance of proteomic technologies as alternative techniques to gain additional meaningful information about these conditions. In addition, the review focuses on recent proteomic studies on cervicovaginal fluid samples for the identification of potential biomarkers. We conclude that the use of proteomic technology for analysis of human cervicovaginal fluid samples is promising and may lead to the discovery of new biomarkers which can improve disease prevention and therapy development.