The influence of lentivirus-mediated CXCR4 RNA interference on hepatic metastasis of colorectal cancer

Selective depletion of metastatic stem cells as therapy for human colorectal cancer

Selective elimination of metastatic stem cells (MetSCs) promises to block metastatic dissemination. Colorectal cancer (CRC) cells overexpressing CXCR4 display trafficking functions and metastasis‐initiating capacity. We assessed the antimetastatic activity of a nanoconjugate (T22‐GFP‐H6‐FdU) that selectively delivers Floxuridine to CXCR4⁺ cells. In contrast to free oligo‐FdU, intravenous T22‐GFP‐H6‐FdU selectively accumulates and internalizes in CXCR4⁺ cancer cells, triggering DNA damage and apoptosis, which leads to their selective elimination and to reduced tumor re‐initiation capacity. Repeated T22‐GFP‐H6‐FdU administration in cell line and patient‐derived CRC models blocks intravasation and completely prevents metastases development in 38–83% of mice, while showing CXCR4 expression‐dependent and site‐dependent reduction in foci number and size in liver, peritoneal, or lung metastases in the rest of mice, compared to free oligo‐FdU. T22‐GFP‐H6‐FdU induces also higher regression of established metastases than free oligo‐FdU, with negligible distribution or toxicity in normal tissues. This targeted drug delivery approach yields potent antimetastatic effect, through selective depletion of metastatic CXCR4⁺ cancer cells, and validates metastatic stem cells (MetSCs) as targets for clinical therapy.

CXC family of chemokines as prognostic or predictive biomarkers and possible drug targets in colorectal cancer

Colorectal cancer (CRC) is the third most common cancer in men and the second most common cancer in women, worldwide. In the early stages of the disease, biomarkers predicting early relapse would improve survival rates. In metastatic patients, the use of predictive biomarkers could potentially result in more personalized treatments and better outcomes. The CXC family of chemokines (CXCL1 to 17) are small (8 to 10 kDa) secreted proteins that attract neutrophils and lymphocytes. These chemokines signal through chemokine receptors (CXCR) 1 to 8. Several studies have reported that these chemokines and receptors have a role in either the promotion or inhibition of cancer, depending on their capacity to suppress or stimulate the action of the immune system, respectively. In general terms, activation of the CXCR1/CXCR2 pathway or the CXCR4/CXCR7 pathway is associated with tumor aggressiveness and poor prognosis; therefore, the specific inhibition of these receptors is a possible therapeutic strategy. On the other hand, the lesser known CXCR3 and CXCR5 axes are generally considered to be tumor suppressor signaling pathways, and their stimulation has been suggested as a way to fight cancer. These pathways have been studied in tumor tissues (using immunohistochemistry or measuring mRNA levels) or serum [using enzyme-linked immuno sorbent assay (ELISA) or multiplexing techniques], among other sample types. Common variants in genes encoding for the CXC chemokines have also been investigated as possible biomarkers of the disease. This review summarizes the most recent findings on the role of CXC chemokines and their receptors in CRC and discusses their possible value as prognostic or predictive biomarkers as well as the possibility of targeting them as a therapeutic strategy.

The Role of IL-33-Dependent Inflammation in the Tumor Microenvironment

There is compelling evidence that inflammation contributes to tumorigenesis. Inflammatory mediators within the tumor microenvironment can either promote an antitumor immune response or support tumor pathogenesis. Therefore, it is critical to determine the relative contribution of tumor-associated inflammatory pathways to cancer development. Interleukin-33 (IL-33) is a member of the IL-1 family of cytokines that is released upon tissue stress or damage to operate as an alarmin. IL-33 has been primarily implicated in the induction of type-2 immune responses. However, recent findings have shown a role of IL-33 in several cancers where it may exert multiple functions. In this review, we will present the current knowledge on the role of IL-33 in the microenvironment of different tumors. We will highlight which cells produce and which cells are activated by IL-33 in cancer. Furthermore, we will explain how IL-33 modulates the tumor-associated inflammatory microenvironment to restrain or promote tumorigenesis. Finally, we will discuss the issues to be addressed first before potentially targeting the IL-33 pathway for cancer therapy.

Effect of RNA inference mediated CXCR4 knockdown on metastasis of AsPC-1 cells

AIM: To explore the changes in proliferation, migration, and invasion of pancreatic cancer line AsPC-1 after CXCR4 is knocked down by RNA interference, and to validate the potential mechanism underlying these changes.

METHODS: AsPC-1 cells were transfected with recombinant lentivirus containing specific shRNA targeting CXCR-4 and included in an experimental group (LV-siCXCR4-1), whereas AsPC-1 cells treated with recombinant lentivirus containing scramble shRNA were used as a negative control (AsPC-1-LV-con). Besides, non-treated AsPC-1 cells were used as a blank control (AsPC-1). After cell cultures were treated with SDF-1α, cell proliferation, migration and invasion in vitro were analyzed, and expression of vascular endothelial growth factor (VEGF), matrix metalloproteinases (MMP)-2 and -9 were quantified.

RESULTS: Under the culture conditions with SFM or 10% normal calf serum, SDF-1α could stimulate the proliferation of AsPC-1 cells and AsPC-1-LV-Con cells (P < 0.01), but had no significant effect on the proliferation of AsPC-1-LV-siCXCR4-1 cells. SDF-1α displayed a promoting effect on the migration and invasion of AsPC-1 and AsPC-1-LV-Con cells (P < 0.01), but showed no significant effect in LV-siCXCR4-1 cells. In the presence of SDF-1α, the protein expression of MMP9 and VEGF in LV-siCXCR4-1 cells was less than that in AsPC-1-LV-Con cells (P < 0.01).

CONCLUSION: RNA interference targeting CXCR-4 could significantly suppress excessive proliferation, migration and invasion of AsPC-1 cells induced by SDF-1α intervention, suggesting that CXCR4/SDF-1 axis contributes to proliferation, invasion and metastasis of pancreatic cancer. RNA interference could be used as a promising approach for therapy of pancreatic cancer.

Curcumin inhibits cell proliferation and promotes apoptosis in human osteoclastoma cell through MMP-9, NF-κB and JNK signaling pathways

Curcumin is a polyphenol compound extracted from ginger plant, turmeric, commonly used in a variety of food coloring and flavoring additives. Curcumin has many effects such as anti-inflammatory, anti-tumor, antioxidant and anti-microbial effects. However, the mechanism underlying the anti-cancer effect of curcumin on human osteoclastoma (Giant cell tumor, GCT) cells remains unclear. The objectives of this study were to determine the efficacy of curcumin on proliferation and apoptosis of GCT cells and its related mechanisms. In our study, cell viability, cellular apoptosis and caspase-3 activity of GCT cells were analyzed using 3.3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay, flow cytometry (FCM) assay and commercial kits, respectively. Next, MMP-9 gene expression quantity, NF-κB activity and JNK protein expression of GCT cells were tested with real-time polymerase chain reaction (RT-PCR), commercial kits and western blotting assay, respectively. Firstly, MMP-9, NF-κB and JNK inhibitors were added into GCT cells and which was researched the mechanism of curcumin on human GCT cells. In this study, the efficacy of curcumin reduced cell viability, induced cellular apoptosis and increased caspase-3 activity of GCT cells. Furthermore, curcumin inhibited the MMP-9 gene expression quantity and NF-κB activity, and activated JNK protein expression in GCT cells. Meanwhile, down-regulation of MMP-9 gene expression quantity and NF-κB activity could promote the anti-cancer effect of curcumin on cell viability of GCT cells. Interesting, down-regulation of JNK protein expression could also reversed the anti-cancer effect of curcumin on cell viability of GCT cells. Taken together, our results suggest that curcumin inhibits cell proliferation and promotes apoptosis in osteoclastoma cell through suppression of MMP-9 and NF-κB, and activation JNK signaling pathways.

IL-33/ST2 pathway contributes to metastasis of human colorectal cancer

Interleukin-33 (IL-33) was recently implicated in cancer pathogenesis. However, the possible effect of IL-33 on tumor progression of colorectal cancer (CRC), which is one of the most commonly diagnosed and lethal cancers worldwide, was still unclear. Here we evaluated the potential role of IL-33/ST2 pathway in metastasis of human CRC. We found an elevated expression of IL-33 and ST2 in tumor tissues of CRC patients. Higher expressions of IL-33 and ST2 were observed in poor-differentiated human CRC cells. Of note, IL-33 stimulation promoted the invasion of human CRC cells in a dose dependent manner. Enhanced IL-33/ST2 signaling promoted CRC metastasis, while attenuated IL-33/ST2 signaling decreased CRC metastasis. In consistent, enforced IL-33 expression in human CRC cells enhanced their growth, metastasis and reduced the survival time in nude mice, while decreased IL-33 expression in human CRC cells inhibited their growth, metastasis and prolonged the survival time in nude mice. Finally, we observed an increased expression of IL-6, CXCR4, MMP2 and MMP9 in response to IL-33/ST2 signaling in human CRC cells, which were crucial for the enhanced metastasis by IL-33 stimulation. Collectively, our findings demonstrated that IL-33/ST2 pathway could contribute to the metastasis of human CRC, which could enlarge the understanding of CRC pathogenesis and provide clues for developing new CRC therapeutics.