Proteomic profiling of tumor-initiating cells in HT-29 human colorectal cancer cells

Methods and biomarkers for early detection, prediction, and diagnosis of colorectal cancer

Colorectal cancer (CRC) is one of the most common digestive diseases worldwide. It has steadily ascended to the top three cancers in terms of incidence and mortality. The primary cause is the inability to diagnose it at an early stage. Therefore, early detection and diagnosis are essential for colorectal cancer prevention. Although there are now various methods for CRC early detection, in addition to recent developments in surgical and multimodal therapy, the poor prognosis and late detection of CRC still remain significant. Thus, it is important to investigate novel technologies and biomarkers to improve the sensitization and specification of CRC diagnosis. Here, we present some common methods and biomarkers for early detection and diagnosis of CRC, we hope this review will encourage the adoption of screening programs and the clinical use of these potential molecules as biomarkers for CRC early detection and prognosis.

Omics technologies for improved diagnosis and treatment of colorectal cancer: Technical advancement and major perspectives

Colorectal cancer (CRC) ranks third among the most commonly occurring cancers worldwide, and it causes half a million deaths annually. Alongside mechanistic study for CRC detection and treatment by conventional techniques, new technologies have been developed to study CRC. These technologies include genomics, transcriptomics, proteomics, and metabolomics which elucidate DNA markers, RNA transcripts, protein and, metabolites produced inside the colon and rectum part of the gut. All these approaches form the omics arena, which presents a remarkable opportunity for the discovery of novel prognostic, diagnostic and therapeutic biomarkers and also delineate the underlying mechanism of CRC causation, which may further help in devising treatment strategies. This review also mentions the latest developments in metagenomics and culturomics as emerging evidence suggests that metagenomics of gut microbiota has profound implications in the causation, prognosis, and treatment of CRC. A majority of bacteria cannot be studied as they remain unculturable, so culturomics has also been strengthened to develop culture conditions suitable for the growth of unculturable bacteria and identify unknown bacteria. The overall purpose of this review is to succinctly evaluate the application of omics technologies in colorectal cancer research for improving the diagnosis and treatment strategies.

Metabolomic analysis reveals the mechanism of aluminum cytotoxicity in HT-29 cells

BACKGROUND

Aluminum (Al) is toxic to animals and humans. The most common sources of human exposure to Al are food and beverages. The intestinal epithelium is the first barrier against Al-induced toxicity. In this study, HT-29, a human colon cancer cell line, was selected as an in vitro model to evaluate the Al-induced alteration in metabolomic profiles and explore the possible mechanisms of Al toxicity.

METHODS

MTT assay was performed to determine the half-maximal inhibitory concentration of Al ions. Liquid chromatography-mass spectrometry (LC-MS) was used for metabolomic analysis, and its results were further confirmed using quantitative reverse transcription polymerase chain reaction (RT-qPCR) of nine selected genes.

RESULTS

Al inhibited the growth of the HT-29 cells, and its half-maximal dose for the inhibition of cell proliferation was found to be four mM. This dose was selected for further metabolomic analysis, which revealed that 81 metabolites, such glutathione (GSH), phosphatidylcholines, phosphatidylethanolamines, and creatine, and 17 metabolic pathways, such as the tricarboxylic acid cycle, pyruvate metabolism, and GSH metabolism, were significantly altered after Al exposure. The RT-qPCR results further confirmed these findings.

CONCLUSION

The metabolomics and RT-qPCR results indicate that the mechanisms of Al-induced cytotoxicity in HT-29 cells include cellular apoptosis, oxidative stress, and alteration of lipid, energy, and amino acid metabolism.

Homogenous and Microbeam X-Ray Radiation Induces Proteomic Changes in the Brains of Irradiated Rats and in the Brains of Nonirradiated Cage Mate Rats

To evaluate microbeam radiation therapy (MRT), for brain tumor treatment, the bystander effect in nonirradiated companion animals was investigated. Adult rats were irradiated with 35 or 350 Gy at the European Synchrotron Research Facility using homogenous irradiation (HR) or MRT to the right brain hemisphere. The irradiated rats were housed with nonirradiated rats. After 48 hours, all rats were euthanized and the frontal lobe proteome was analyzed using 2-dimensional electrophoresis and mass spectrometry. Proteome changes were determined by analysis of variance (P < .05). Homogenous irradiation increased serum albumin, heat shock protein 71 (HSP-71), triosephosphate isomerase (TPI), fructose bisphosphate aldolase (FBA), and prohibitin and decreased dihydrolipoyl dehydrogenase (DLD) and pyruvate kinase. Microbeam radiation therapy increased HSP-71, FBA, and prohibitin, and decreased aconitase, dihydropyrimidinase, TPI, tubulin DLD, and pyruvate kinase. Cage mates with HR irradiated rats showed increased HSP-71 and FBA and decreased pyruvate kinase, DLD, and aconitase. Cage mates with MRT irradiated rats showed increased HSP-71, prohibitin, and FBA and decreased aconitase and DLD. Homogenous irradiation proteome changes indicated tumorigenesis, while MRT proteome changes indicated an oxidative stress response. The bystander effect of proteome changes appeared antitumorigenic and inducing radioresistance. This investigation also supports the need for research into prohibitin interaction with HSP-70/71 chaperones and cancer therapy.

Biomarker discovery by proteomics-based approaches for early detection and personalized medicine in colorectal cancer

About one million people per year develop colorectal cancer (CRC) and approximately half of them die. The extent of the disease (i.e. local invasion at the time of diagnosis) is a key prognostic factor. The 5-year survival rate is almost 90% in the case of delimited CRC and 10% in the case of metastasized CRC. Hence, one of the great challenges in the battle against CRC is to improve early diagnosis strategies. Large-scale proteomic approaches are widely used in cancer research to search for novel biomarkers. Such biomarkers can help in improving the accuracy of the diagnosis and in the optimization of personalized therapy. Herein, we provide an overview of studies published in the last 5 years on CRC that led to the identification of protein biomarkers suitable for clinical application by using proteomic approaches. We discussed these findings according to biomarker application, including also the role of protein phosphorylation and cancer stem cells in biomarker discovery. Our review provides a cross section of scientific approaches and can furnish suggestions for future experimental strategies to be used as reference by scientists, clinicians and researchers interested in proteomics for biomarker discovery.

PFN2, a novel marker of unfavorable prognosis, is a potential therapeutic target involved in esophageal squamous cell carcinoma

Background

Esophageal squamous cell carcinoma (ESCC) is one of the most aggressively malignant tumors with dismal prognosis. Profilin 2 (PFN2) is an actin-binding protein that regulates the dynamics of actin polymerization and plays a key role in cell motility. Recently, PFN2 have emerged as significant regulators of cancer processes. However, the clinical significance and biological function of PFN2 in ESCC remain unclear.

Methods

PFN2 protein expression was validated by immunohistochemistry (IHC) on tissue microarray from Chinese Han and Kazakh populations with ESCC. The associations among PFN2 expression, clinicopathological features, and prognosis of ESCC were analyzed. The effects on cell proliferation, invasion and migration were examined using MTT and Transwell assays. Markers of epithelial–mesenchymal transition (EMT) were detected by Western blot analysis.

Results

Compared with normal esophageal epithelium (NEE), PFN2 protein expression was markedly increased in low-grade intraepithelial neoplasia (LGIN), high-grade intraepithelial neoplasia (HGIN), and ESCC, increased gradually from LGIN to ESCC, and finally reached high grade in HGIN in the Han population. Similarly, PFN2 protein was more overexpressed in ESCC than in NEE in the Kazakh population. The results of Western blot analysis also showed that PFN2 expression was significantly higher in the ESCC tissue than in a matched adjacent non-cancerous tissue. PFN2 expression was positively correlated with invasion depth and lymph node metastasis. High PFN2 expression was significantly correlated with short overall survival (OS) (P = 0.023). Cox regression analysis revealed that PFN2 expression was an independent prognostic factor for poor OS in ESCC. Downregulation of PFN2 inhibited, rather than proliferated, cell invasion and migration, as well as induced an EMT phenotype, including increased expression of epithelial marker E-cadherin, decreased mesenchymal marker Vimentin, Snail, Slug and ZEB1, and morphological changes in ESCC cells in vitro.

Conclusions

Our findings demonstrate that PFN2 has a novel role in promoting ESCC progression and metastasis and portending a poor prognosis, indicating that PFN2 could act as an early biomarker of high-risk population. Targeting PFN2 may offer a promising therapeutic strategy for ESCC treatment.

Electronic supplementary material

The online version of this article (doi:10.1186/s12967-016-0884-y) contains supplementary material, which is available to authorized users.

Crude extract of Rheum palmatum L inhibits migration and invasion of LS1034 human colon cancer cells acts through the inhibition of matrix metalloproteinase-2/-9 by MAPK signaling

Crude extract of Rheum palmatum L. (CERP) has been used to treat different diseases in the Chinese population for decades. In this study, we investigated the anti-metastasis effects of CERP on LS1034 human colorectal cancer cells in vitro and examined potential mechanisms of its effects. CERP significantly inhibited cell migration and invasion of LS1034 cells. We also found that CERP inhibited protein levels of matrix metalloproteinases-2 (MMP-2) and matrix metalloproteinases-9 (MMP-9), and cytosolic NF-kB p65, RHO A, ROCK 1. Furthermore, we found CERP inhibited protein levels of GRB2, SOS1, MKK7, FAK, Rho A, ROCK 1, VEGF, PKC, AKT, phosphor-AKT (Thr308), Cyclin D, iNOS, COX2, NF-kB p65, p-ERK1/2, p-JNK1/2, p-p38, p-c-jun, MMP-2, MMP-9, MMP-1, MMP-7, MMP-10, UPA and increased the protein level of Ras in LS1034 cells. In conclusion, our results suggest that CERP may be used as a novel anti-metastasis agent for the treatment of human colon cancer cells.

Profilin 2 promotes migration, invasion, and stemness of HT29 human colorectal cancer stem cells

We investigated the role of profilin 2 in the stemness, migration, and invasion of HT29 cancer stem cells (CSCs). Increased and decreased levels of profilin 2 significantly enhanced and suppressed the self-renewal, migration, and invasion ability of HT29 CSCs, respectively. Moreover, profilin 2 directly regulated the expression of stemness markers (CD133, SOX2, and β-catenin) and epithelial mesenchymal transition (EMT) markers (E-cadherin and snail). CD133 and β-catenin were up-regulated by overexpression of profilin 2 and down-regulated by depletion of profilin 2. SOX2 was decreased by profilin 2 depletion. E-cadherin was not influenced by profilin 2- overexpression but increased by profilin 2- knockdown. The expression of snail was suppressed by profilin 2- knockdown. We speculated that stemness and the EMT are closely linked through profilin 2-related pathways. Therefore, this study indicates that profilin 2 affects the metastatic potential and stemness of colorectal CSCs by regulating EMT- and stemness-related proteins.

The cancer stem cell hypothesis: a guide to potential molecular targets

Common cancer theories hold that tumor is an uncontrolled somatic cell proliferation caused by the progressive addition of random mutations in critical genes that control cell growth. Nevertheless, various contradictions related to the mutation theory have been reported previously. These events may be elucidated by the persistence of residual tumor cells, called Cancer Stem Cells (CSCs) responsible for tumorigenesis, tumor maintenance, tumor spread, and tumor relapse. Herein, we summarize the current understanding of CSCs, with a focus on the possibility to identify specific markers of CSCs, and discuss the clinical application of targeting CSCs for cancer treatment.

Overexpression of B7-H3 in CD133+ colorectal cancer cells is associated with cancer progression and survival in human patients

Cancer stem-like cells are enriched in CD133-positive (CD133(+)) colorectal cancer (CRC) cells. To date, the biological significance of CD133 expression in cancer stem-like cells is still unknown. B7-H3, a costimulatory molecule, plays a pivotal role in tumor immune escape by inhibiting the functions of T cells. To identify a new marker to predict the tumor grade of CRC, we analyzed the expression of B7-H3 and CD133 in colorectal tumor samples, and their clinical significance was determined. By using a series of techniques including pathologic tissue microarray technology, immunohistochemistry, and immunofluorescent staining, we found B7-H3 was expressed in 56.73% of the CRC cases (59/104) sampled; CD133 was detected in 26.92% of the CRC cases (28/104) sampled. Further analysis indicated that 22 of these CD133(+) samples expressed B7-H3. We also found coexpression of CD133 and B7-H3 in tumor tissue samples (r = 0.321, P < 0.01). Moreover, in contrast to individual CD133 or B7-H3 expression, the coexpression of B7-H3 and CD133 was evidently associated with the depth of tumor invasion, lymphatic metastasis, distant metastasis, and Dukes' stage, suggesting it is a valuable biomarker for the progression of CRC. Indeed, the patients with coexpression of B7-H3 and CD133 had a poorer survival than the other patients (P < 0.05). In summary, our results reveal that B7-H3 was aberrantly expressed in CD133(+) CRC cells, and the expression level was closely associated with tumor progression.

Treatment with aspirin inhibits the expression of CD133 in human colorectal cancer cells HT-29 and SW480

AIM: To investigate the effect of treatment with aspirin on CD133 protein expression in colorectal cancer cell (CRC) lines.

METHODS: HT-29 and SW480 cells were treated with different concentrations of aspirin (0.0, 2.5, 5.0, or 10.0 mmol/L), and the expression of CD133 was detected by flow cytometry.

RESULTS: Flow cytometry results demonstrated that the proportions of CD133⁺ cells were 88.37% ± 1.00% and 65.22% ± 1.52% in HT-29 and SW480 cells, respectively. Treatment with aspirin significantly reduced the expression of CD133 in HT-29 and SW480 cells in a concentration-dependent manner (both P < 0.05).

CONCLUSION: Treatment with aspirin can inhibit the expression of CD133 in HT-29 and SW480 cells in a concentration-dependent manner.