Identification of microRNA-target interaction in APRIL-knockdown colorectal cancer cells

Expression of Immune-Related and Inflammatory Markers and Their Prognostic Impact in Colorectal Cancer Patients

The tumor microenvironment of colorectal cancer (CRC) is heterogenous; thus, it is likely that multiple immune-related and inflammatory markers are simultaneously expressed in the tumor. The aim of this study was to identify immune-related and inflammatory markers expressed in freshly frozen CRC tissues and to investigate whether they are related to the clinicopathological features and prognosis of CRC. Seventy patients with CRC who underwent curative surgical resection between December 2014 and January 2017 were included in this study. Tissue samples were obtained from tumor and non-tumor areas in the patients' colons. The concentrations of immune-related markers (APRIL/TNFSF13, BAFF, LAG-3, PD-1, PD-L1, and CTLA-4) and inflammatory markers (CHIT, MMP-3, osteocalcin, pentraxin-3, sTNF-R1, and sTNF-R2) in the samples were measured using the Bio-plex Multiplex Immunoassay system. The concentrations of APRIL/TNFSF13, BAFF, and MMP-3 in the samples were significantly high; thus, we conducted analyses based on the cut-off values for these three markers. The high-APRIL/TNFSH13-expression group showed a significantly higher rate of metastatic lesions than the low-expression group, whereas the high-MMP-3-expression group had higher CEA levels, more lymph node metastases, and more advanced disease stages than the low-expression group. The five-year disease-free survival of the high-MMP-3-expression group was significantly shorter than that of the low-expression group (65.1% vs. 90.2%, p = 0.033). This study provides evidence that the APRIL/TNFSF13, BAFF, and MMP-3 pathway is overexpressed in CRC tissues and is associated with unfavorable clinicopathological features and poor prognosis in CRC patients. These markers could serve as diagnostic or prognostic biomarkers for CRC.

Role of the APRIL molecule in solid tumors

The APRIL molecule, produced by immune cells, their precursors, and cancer cells, is one of the important factors that influences the process of survival and proliferation of cancer cells. In the present review, we summarize the current knowledge on the effects of APRIL on human cancer development and develop a scheme demonstrating the mechanism of the action of APRIL on solid tumors. Understanding the effects of APRIL, including the intracellular signal transduction pathway, may be key for the use of this protein as a biomarker of the cancer process. The correlations observed between APRIL levels and cancer parameters (e.g., disease stage and presence of malignant phenotypes) indicate that APRIL may play an important role, not only in the diagnostic process, but also as a therapeutic target in various cancers.

APRIL is Involved in the Proliferation and Metastasis of Acute Lymphoblastic Leukemia Cells

Our previous work showed that a proliferation-inducing ligand (APRIL) was involved in the development of acute lymphoblastic leukemia (ALL) in children. However, the precise role of APRIL in ALL remains unknown. To investigate this issue, we silenced and overexpressed APRIL in Nalm-6 ALL cells using short hairpin RNA targeting the APRIL gene and recombinant human APRIL, respectively, and evaluated the effects on cell proliferation, apoptosis, and migration. APRIL mRNA and APRIL and matrix metalloproteinase-2 protein levels were evaluated by semiquantitative reverse transcription-polymerase chain reaction (RT-PCR) and western blott, respectively. We found that APRIL expression was reduced by shRNA-mediated knockdown in Nalm-6 cells; this was associated with a decrease in cell proliferation (P<0.05). APRIL knockdown increased apoptosis (P<0.01) but suppressed cell migration along with matrix metalloproteinase-2 protein level. Overexpressing recombinant human APRIL had the opposite effects in each case (P<0.05). These results demonstrate a link between APRIL expression and ALL development and suggest that APRIL is a potential therapeutic target for ALL treatment.

Identification of the sAPRIL binding peptide and its growth inhibition effects in the colorectal cancer cells

BACKGROUND

A proliferation-inducing ligand (APRIL) is a member of the tumor necrosis factor (TNF) super family. It binds to its specific receptors and is involved in multiple processes during tumorigenesis and tumor cells proliferation. High levels of APRIL expression are closely correlated to the growth, metastasis, and 5-FU drug resistance of colorectal cancer. The aim of this study was to identify a specific APRIL binding peptide (BP) able to block APRIL activity that could be used as a potential treatment for colorectal cancer.

METHODS

A phage display library was used to identify peptides that bound selectively to soluble recombinant human APRIL (sAPRIL). The peptides with the highest binding affinity for sAPRIL were identified using ELISA. The effects of sAPRIL-BP on cell proliferation and cell cycle/apoptosis in vitro were evaluated using the CCK-8 assay and flow cytometry, respectively. An in vivo mouse model of colorectal cancer was used to determine the anti-tumor efficacy of the sAPRIL-BP.

RESULTS

Three candidate peptides were characterized from eight phage clones with high binding affinity for sAPRIL. The peptide with the highest affinity was selected for further characterization. The identified sAPRIL-BP suppressed tumor cell proliferation and cell cycle progression in LOVO cells in a dose-dependent manner. In vivo in a mouse colorectal challenge model, the sAPRIL-BP reduced the growth of tumor xenografts in nude mice by inhibiting proliferation and inducing apoptosis intratumorally. Moreover, in an in vivo metastasis model, sAPRIL-BP reduced liver metastasis of colorectal cancer cells.

CONCLUSIONS

sAPRIL-BP significantly suppressed tumor growth in vitro and in vivo and might be a candidate for treating colorectal cancers that express high levels of APRIL.

Amelioration of colorectal cancer using negative lipidoid nanoparticles to encapsulate siRNA against APRIL by enema delivery mode

A proliferation-inducing ligand (APRIL) is a key cell proliferation-regulatory molecule and have been investigated well enough in immunity regulation and a few of immune diseases. APRIL can stimulate tumor cell growth and is up-expressed in cancer tissues, especially in CRC (colorectal cancer). However, whether inhibition of APRIL can regulate tumor-relative genes expression in vivo and subsequently ameliorate the pathological progress of CRC remains obscure. To address this question, we developed a novel negative lipidoid nanoparticles (NLNs) encapsulating small interference RNA (siRNA) for selectively silencing APRIL in the parenchyma of CRC focus in vivo, which uptake proceeded through a lipid raft endocytotic pathway. Local enema delivery of APRIL-NLNs silenced APRIL in CRC cells and animal models, and then ameliorated experimentally the progress of CRC by suppressing CRC cell proliferation, metastasis, and apoptosis-related cytokine expression and did not affect the function of liver and kidneys and not trigger the immune response of CRC models. This study reveals APRIL to be a potential anti-CRC target by in vivo experiments, and suggests that the application of similar modes of siRNA delivery may be feasible in other therapeutic settings.

The up-regulation expression of APRIL is a marker of glottic malignant disease

A proliferation-inducing ligand (APRIL) is a member of the tumor necrosis factor (TNF) family. Recent studies have implied that APRIL is closely related to solid tumors and hematological tumors, indicating that APRIL could be a potential marker to diagnose glottic malignant disease. The purpose of this study was to investigate the difference of the APRIL mRNA and protein expression in glottic malignant disease, corresponding adjacent non-neoplastic tissues and glottic benign lesion, and detect the influence of different clinical parameter in glottic carcinoma. The APRIL mRNA expression in the glottic carcinoma, corresponding adjacent non-neoplastic tissues and glottic polypus tissue samples from patients was detected by qRT-PCR. Moreover, we studied the APRIL protein expression in pathological sections of other patients with glottic carcinoma or glottic polypus using immunohistochemistry. All the patients with different clinical parameter underwent surgery. Using qRT-PCR, we revealed an up-regulation of APRIL mRNA expression in glottic carcinoma as compared to glottic polypus and corresponding adjacent non-neoplastic tissues, but no significant difference with T stages, histopathological differentiation grade or lymph node metastasis in glottic carcinoma. The result of the immunohistochemistry was the same, with no influence of different clinical parameter in glottic carcinoma. These results strongly suggest that APRIL could be a potential diagnosed marker to distinguish glottic malignant disease from glottic benign lesion, and it may play an important role in the development of glottic malignant disease.

Serum sAPRIL: a potential tumor-associated biomarker to colorectal cancer

OBJECTIVE

The purpose of our study was to investigate the serum levels of soluble a-proliferation-inducing ligand (sAPRIL) in patients with colorectal cancer (CRC), benign intestinal disease and healthy volunteers and explore the potential possibility of sAPRIL severing as a CRC biomarker.

METHODS

Our investigation was conducted on 35 blood samples obtained from CRC patients, 32 blood samples from patients with benign intestinal diseases and 31 blood samples from healthy volunteers. The sAPRIL concentrations were examined by an enzyme-linked immunosorbent assay (ELISA) and data were analyzed with non-parametric Mann-Whitney U-test and X²-test. The correlation relationship between sAPRIL and CEA, as well as sAPRIL and CA19-9 was assessed by non-parametric Spearmen's correlation test, respectively.

RESULTS

The median value of sAPRIL in the malignant group was 10.43 ng/mL, compared with those of the benign group (4.89 ng/mL) and control group (3.30 ng/mL), respectively, which had an obvious significance (P<0.0003). Area under the receiver-operating characteristic (ROC) curve for sAPRIL was 0.854 (95% CI, 0.776-0.933). The optimal cut-off level of sAPRIL was 5.49 ng/mL. Serum sAPRIL had a positive correlation with CEA (r=0.637, P=0.000) and CA19-9 (r=0.357, P=0.008) in 35 patients with colorectal cancer. sAPRIL showed higher sensitivity (82.9%) than those of CEA (74.3%) and CA19-9 (65.7%) in CRC, respectively.

CONCLUSION

The results indicated that serum sAPRIL, as a potential biomarker, had a positive diagnostic value for colorectal cancer.

APRIL induces tumorigenesis and metastasis of colorectal cancer cells via activation of the PI3K/Akt pathway

A proliferation-inducing ligand (APRIL) is highly expressed in colorectal cancer (CRC) tissues and cell lines. However, the biological functions and precise signals elicited by APRIL in CRC have not been fully understood. Here, we used small interfering RNA to selectively deplete APRIL and to determine its tumorigenic effects in a CRC cell line SW480 both in vitro and in vivo. Knockdown of APRIL in SW480 cells was associated with modulation of cell proliferation as well as reduction of cell migration and invasion in vitro. Moreover APRIL-knockdown SW480 cells displayed markedly inhibited tumor growth and decreased metastasis to the liver in immunodeficient mice upon subcutaneous injection. Importantly, we observed that downregulation of APRIL in SW480 cells resulted in greatly decreased activity of phosphoinositide 3-kinase (PI3K)/Akt pathway. In addition, we observed that recombinant human APRIL mediated activation of the PI3K/Akt pathway in CRC cells resulting in induced expression of important cell cycle proteins and matrix metalloproteinases in a PI3K/Akt dependent manner. This was concurrent with marked cell growth viability as well as increased cell migration and invasion. Together, these compelling data suggest that APRIL-induced tumorigenesis and metastasis of CRC cells may be accomplished through activation of the PI3K/Akt pathway. These findings may lead to a better understanding of the biological effects of APRIL and may provide clues for identifying novel therapeutic and preventive molecular markers for CRC.