Understanding the colon cancer stem cells and perspectives on treatment

Prognostic significance of CD133 and ezrin expression in colorectal carcinoma

Despite the improvement in the diagnostic and the therapeutic modalities, colorectal cancer (CRC) morbidity and mortality remain high in both the developed and the developing countries. So, we are in a need to recognize new efficient diagnostic and prognostic biomarkers of CRC. That may help in providing individualized targeted therapy for this lethal malignancy. In this study, we investigated the expression and the prognostic significance of CD133 and ezrin mRNA and protein by quantitative RT-PCR and immunohistochemical analysis in primary CRC cases and the surrounding normal colonic mucosa. The correlations between the expression of both markers and clinicopathological parameters were performed. Compared to control, the expression of CD133 and ezrin mRNA and protein in CRC were significantly up-regulated (P < 0.05). In addition, a strong positive correlation between both markers was found (r = 0.867, P < 0.001). Moreover, elevated levels of both markers were significantly associated with the stage, lymph node involvement, distant metastasis, and recurrence at both mRNA and protein levels (P < 0.05). In conclusion, there is a clinical significance of CD133 and ezrin as potential biomarkers for predicting CRC patients of aggressive behavior and poor prognosis. © 2017 IUBMB Life, 69(5):328-340, 2017.

Global dynamics of a colorectal cancer treatment model with cancer stem cells

We present and analyze a mathematical model of the treatment of colorectal cancer using a system of nonlinear ordinary differential equations. The model describes the effectiveness of immunotherapy and chemotherapy for treatment of tumor cells and cancer stem cells (CSCs). The effects of CD8⁺T cells, natural killer cells, and interleukin proteins on tumor cells and CSCs under the influence of treatment are also illustrated. Using the method of localization of compact invariant sets, we present conditions on treatment parameters to guarantee a globally attracting tumor clearance state. Numerical simulations using estimated parameters from the literature are included to showcase various global dynamics of the model.

Effect of Recepteur d'Origine Nantais expression on chemosensitivity and tumor cell behavior in colorectal cancer

Recepteur d'Origine Nantais (RON) expression is known to induce oncogenic properties including tumor cell growth, survival, motility, angiogenesis and chemoresistance. In the present study, we evaluated whether RON affects chemosensitivity and oncogenic behavior of colorectal cancer cells and investigated its prognostic value in colorectal cancer. To evaluate the impact of RON on chemosensitivity and tumor cell behavior, we treated colorectal cancer cells with small interfering RNAs specific to RON. This was followed by flow cytometric analyses and migration, Matrigel invasion and endothelial tube formation assays. The expression of RON was investigated by immunohistochemistry in colorectal cancer tissues. TUNEL assay and immunohistochemical staining for CD34 and D2-40 were deployed to determine apoptosis, angiogenesis and lymphangiogenesis. RON knockdown enhanced 5-fluorouracil (FU)-induced apoptosis by upregulating the activities of caspases and expression of proapoptotic genes. Moreover, it enhanced 5-FU-induced cell cycle arrest by decreasing the expression of cyclins and cyclin‑dependent kinases and inducing that of p21. Furthermore, RON knockdown augmented the 5-FU-induced inhibition of invasion and migration of colorectal cancer cells. The β-catenin signaling cascade was blocked by RON knockdown upon 5-FU treatment. RON knockdown also decreased endothelial tube formation and expression of VEGF-A and HIF-1α and increased angiostatin expression. Furthermore, it inhibited lymphatic endothelial cell tube formation and the expression of VEGF-C and COX-2. RON expression was observed to be associated with age, tumor size, lymphovascular and perineural invasion, tumor stage, lymph node and distant metastasis, and poor survival rate. The mean microvessel density value of RON-positive tumors was significantly higher than that of RON-negative ones. These results indicate that RON is associated with tumor progression by inhibiting chemosensitivity and enhancing angiogenesis in colorectal cancer.

Colorectal cancer cells are resistant to anti-EGFR monoclonal antibody through adapted autophagy

The epidermal growth factor receptor (EGFR) signaling plays a key role in the initiation, progression, growth and metastases of colorectal carcinoma (CRC). Monoclonal antibody against EGFR (aEGFR; Cetuximab) has been used in treating CRC but some CRCs appeared to be resistant to aEGFR therapy, with undetermined mechanisms. Here, we studied the effects of aEGFR on CRC cells in vitro. We found that aEGFR dose-dependently activated Beclin-1 in 2 CRC cell lines, HT29 and SW480. Inhibition of autophagy significantly increased the aEGFR-induced CRC cell death in an CCK-8 assay. Moreover, microRNA (miR)-216b levels were significantly downregulated in aEGFR-treated CRC cells. Bioinformatics study showed that miR-216b targeted the 3'-UTR of Beclin-1 mRNA to inhibit its translation, which was confirmed by luciferase reporter assay. Together, these data suggest that aEGFR may decrease miR-216b levels in CRC cells, which subsequently upregulates Beclin-1 to increase CRC cell autophagy to antagonize aEGFR-induced cell death. Strategies that increase miR-216b levels or inhibit cell autophagy may improve the outcome of aEGFR treatment in CRC therapy.

Decreasing lncRNA HOTAIR expression inhibits human colorectal cancer stem cells

Research on the relationship between aberrant long non-coding RNA (lncRNA) and cancer stem cell (CSC) biology in cancer patients has been recently gaining attention. The goal of this study was to investigate whether the decreasing lncRNA HOTAIR expression would inhibit human colorectal cancer (CRC) stem cells. CD133(+)CSCs were isolated from human CRC LoVo cell line by using a magnetic-activated cell sorting system, and were transfected with the expression vector-based small hairpin RNA targeting HOTAIR (shHOTAIR). The ability of cellular proliferation, migration, invasion, colony-forming, and the epithelial-mesenchymal transition (EMT)-associated molecule expression as well as the tumorigenicity of CD133(+)-shHOTAIR were evaluated by the MTT, wound-healing, cellular invasion, colony formation and Western blot assays, respectively. This study found that, when compared with control cells in vitro, CD133(+)-shHOTAIR exhibited the decreased HOTAIR expression, suppressed cellular proliferation, migration, invasion, colony-forming, and inhibited the Vimentin expression with increased E-cadherin expression. In particular, the down-regulation of the HOTAIR expression in CD133(+)CSCs markedly attenuated the tumor growth and lung metastasis in xenograft nude mice. Taken together, this study found that down-regulating the HOTAIR expression in CD133(+)CSCs could serve as a potential anti-cancer regimen to inhibit the invasiveness and metastasis of CRC CSCs.

Polymeric nanoparticles for colon cancer therapy: overview and perspectives

Colorectal cancer (CRC) is the third-most common malignant tumour and is associated with high morbidity and mortality worldwide.

Cancer stem cells and exosome signaling

Exosomes have been recognized as mediators of intercellular communication among different cell populations in various biological model systems. By transfer of signaling molecules such as proteins, lipids, and RNAs between different cell types, exosomes are implicated in both physiological and pathological processes. The tumor microenvironment consists of multiple types of cells including adult stem cells, cancer stem cells, and stromal cells. These cells are known to intercommunicate with each other thereby modulating tumor progression. Recent studies have provided evidence demonstrating that exosomes mediate the interactions among different types of cells within the tumor microenvironment, providing new insight into how these cells interact with each other through exosome signaling. This review is focused on recent studies that have examined exosome-mediated intercommunication among cancer stem cells, adult stem cells, cancer cells, and stromal cells within the tumor microenvironment. Based on the current literature, it seems clear that adult stem cells and cancer stem cells secret exosomes that can be transferred to their surrounding cells thereby modulating cancer progression. Likewise, cancer cells and stromal cells also release exosomes that can be taken up by cancer stem cells or adult stem cells, leading to alterations to their phenotype. The molecular mechanisms and biological consequences of the exosome-mediated interactions of these cells remain to be further elucidated. A better understanding of how exosomes mediate intercellular communication in the tumor microenvironment and the specific biological consequences of these interactions will likely offer new opportunities in the development of diagnostic or therapeutic strategies against cancer.

The rationale for liquid biopsy in colorectal cancer: a focus on circulating tumor cells

Capturing circulating tumor cells (CTCs) and/or circulating tumor DNA from blood, which represents a precious source of biological material derived from both primary and metastatic tumors, has been named a 'liquid biopsy'. While the circulating tumor DNA might be more representative of the bulk of the metastatic tumor, CTCs are thought to reflect more of the metastases-initiating cells. Consequently, a liquid biopsy made of tumor cells and tumor DNA that is able to track cancer evolution, as a fingerprint of the patient's individual tumor, and is easy to perform at every stage of the disease course, sounds attractive. This article mainly focuses on the applications of CTCs to track tumor dynamics in real time using colorectal cancer as a model system. The analysis of viable CTCs at DNA, RNA and protein levels, as well as their expansion in vitro, may allow deep investigation of the features of metastases-initiating cells.