[MACC1 knockdown enhances RSL3-induced ferroptosis in human colorectal cancer cells by inhibiting GPX4 expression]

OBJECTIVE

To investigate the effect of MACC1 on RSL3-induced ferroptosis in colorectal cancer cells and explore its molecular mechanism.

METHODS

MACC1 expression was detected in SW620, HCT116, LOVO and RKO cells using Western blotting. The effects of different concentrations of RSL3 (an inducer of ferroptosis) or Fer-1 (an inhibitor of ferroptosis) alone, or 10 μmol/L RLS3 combined with 10 μmol/L Fer-1, on viability of SW620 cells were examined using MTT assay. The survival of SW620 cells with mRNA interference of MACC1 was analyzed following treatment with RSL3, and RT-qPCR and Western blotting were performed to detect the changes in MACC1 expressions after RSL3 treatment at different concentrations and the changes in GPX4 expression after MACC1 knockdown. Flow cytometry and laser confocal microscopy were used to analyze the changes in ROS-induced lipid peroxidation in SW620 cells after MACC1 knockdown.

RESULTS

SW620 cells had the highest MACC1 expression among the 4 colorectal cancer cell lines. Treatment with RSL3 significantly inhibited the viability of SW620 cells in a dose-dependent manner, while Fer-1 did not significantly affect the survival of SW620 cells. RSL3 alone reduced SW620 cell survival by 50% (P < 0.01), and the combined treatment with RSL3 and Fer-1 caused no significant changes in cell survival (P > 0.05). Treatment with RSL3 concentration-dependently suppressed MACC1 expressions at both the mRNA and protein levels in SW620 cells (P < 0.01). MACC1 knockdown obviously enhanced the cytotoxic effect of RSL3, inhibited the expression of GPX4, and increased ROS-induced lipid peroxidation in SW620 cells (P < 0.05).

CONCLUSION

MACC1 knockdown enhances RSL3-induced ferroptosis in cultured colorectal cancer cells by inhibiting the expression of GPX4.

Overexpression of metastasis-associated in colon cancer 1 in retinoblastoma

INTRODUCTION

Metastasis-associated in colon cancer 1 (MACC1), one of the prognostic markers for colonic and other tumours was noted to be overexpressed in retinoblastoma (Rb) Y79 cancer stem cells. This prompted us to evaluate its expression in primary Rb tumour and serum samples with clinicopathologic correlation. The interacting partner, c-MET was also evaluated in primary tumour tissues to explore the activation of MACC1 signaling.

METHODOLOGY

This study was done following institutional review board approval from participating institutes. Semiquantitative gene expression for MACC1 was evaluated using formalin-fixed paraffin-embedded sections and unfixed tumour samples from primary Rb cases (n = 44). Immunolocalization for MACC1 was assessed in primary Rb tumours (n = 22), bone marrow aspirates with metastasis (n = 3), and c-MET expression was also assessed in Rb tumours (n = 17). Serum MACC1 levels were analysed using enzyme-linked immunosorbent assay in samples collected from Rb patients undergoing enucleation (n = 31), Rb patients with proven clinical metastasis (n = 3), and compared to appropriate controls. Clinicopathologic correlation of MACC1 expression was analysed using the medical records with specific reference to histologic risk factors (HRF) for metastasis and differentiation.

RESULTS

High expression of MACC1 gene was noted in all the tumour samples (n = 44), more so in cases with versus without HRF (p < 0.0001). In cases with HRF, MACC1 and c-MET showed diffuse nuclear and cytoplasmic staining whereas it was predominantly cytoplasmic in cases without HRF. Mean immunoreactivity score of MACC1 and c-MET tissue immunolocalization revealed that cases with HRF showed significantly higher expression compared to cases without HRF (p < 0.05). Unlike the findings in colonic tumours, serum levels of MACC1 were lower in patients compared to normal controls.

CONCLUSION

Overexpression of MACC1 and c-MET in retinoblastoma tissues, specifically those with risk factors for metastasis, suggests its role in proliferation and possibly in invasion. However, the current data do not support it to be a clinical prognostic marker in retinoblastoma tumours. The inverse serum expression is an intriguing finding, which warrants further studies especially in retinoblastoma.

MicroRNA-432 is downregulated in osteosarcoma and inhibits cell proliferation and invasion by directly targeting metastasis-associated in colon cancer-1

The aberrant expression of microRNAs (miRNAs/miRs) in osteosarcoma (OS) has been demonstrated in previous studies, and deregulation of miRNA expression has been associated with several types of cancer, including OS development and progression. Therefore, identifying the functional role of miRNAs in OS onset and development may facilitate the identification of novel and effective therapeutic targets for the treatment of patients with OS. Previous studies have demonstrated that miR-432 is involved in tumor formation and progression in several types of cancer. However, the expression pattern, functional role and underlying mechanism of miR-432 in OS remain unknown. In the current study, reverse transcription-quantitative polymerase chain reaction (RT-qPCR) was used to measure miR-432 expression levels in OS tissue samples and cell lines. The effect of miR-432 overexpression on OS cell proliferation and invasion was detected using Cell Counting Kit-8 and Transwell invasion assays, respectively. Bioinformatics analysis was used to predict metastasis-associated in colon cancer 1 (MACC1) as a putative target of miR-432 and this was confirmed using a dual-luciferase reporter assay, RT-qPCR and western blot analysis. The current study demonstrated that miR-432 expression levels were significantly reduced in OS tissue samples and cell lines. In addition, functional assays revealed that overexpression of miR-432 significantly decreased OS cell proliferation and invasion. Furthermore, MACC1 was identified as a direct target gene of miR-432 in OS. MACC1 expression levels were significantly increased in OS tissue samples and an inverse correlation was observed between miR-432 and MACC1 expression in OS tissue samples. In addition, rescue experiments demonstrated that overexpression of MACC1 partially reversed the anti-proliferative and anti-invasive effects of miR-432 in OS cells. In conclusion, the present study demonstrated that miR-432 inhibited OS cell proliferation and invasion in vitro through direct targeting of MACC1, and miR-432 may be a potential therapeutic target for the treatment of OS.

MACC1 and HGF are associated with survival in patients with gastric cancer

Metastasis-associsated in colon cancer 1 (MACC1), a newly identified oncogene, promotes tumor cell proliferation and invasion. In the present study, the expression of MACC1, hepatocyte growth factor (HGF) and its receptor, MET proto-oncogene (c-Met), was investigated in human gastric cancer tissues and adjacent normal tissues by immunohistochemistry. The association between the expression levels of the proteins and the clinicopathological parameters of the tumors were statistically analyzed. Furthermore, lentiviral particles expressing MACC1 were used to infect the hepatic satellite cell (HSC) line LX2. The expression of α-smooth muscle actin (SMA), HGF, matrix metallopeptidase (MMP)-2 and MMP-9 in human HSCs was examined by western blotting and reverse transcription-quantitative polymerase chain reaction. Transwell assays were used to measure the effect of MACC1-infected or non-infected HSCs on the migration and invasion abilities of MKN45 and MKN74 gastric carcinoma cells in vitro. The results demonstrated that positive protein expression of MACC1, HGF and c-Met was significantly higher in human gastric cancer tissues compared with adjacent normal tissues. Positive expression of MACC1 and c-Met in gastric cancer tissues had no correlation with the sex, age, tumor location and peritoneal metastasis of patients, but was significantly correlated with tumor size, depth of tumor invasion, lymph node metastasis, TNM stage, histological differentiation, and overall (5 years) and disease-free survival (5 years). Positive expression of each MACC1, HGF and c-Met protein was demonstrated to be positively correlated with each other in human gastric cancer tissues. Western blotting results confirmed that MACC1 protein was overexpressed in MACC1-overexpressing lentivirus-infected HSCs. Overexpression of MACC1 significantly increased HGF, MMP-2, MMP-9 and α-SMA expression levels in HSCs. Results from the Transwell assays indicated an increase in the number of MKN45 or MKN74 cells migrating towards MACC1-overexpressing HSCs, compared with control HSCs. These findings suggested that MACC1 may regulate the expression of HGF, MMP-2 and MMP-9 in HSCs, and may thus promote migration and invasion of gastric carcinoma cells. MACC1, HGF and c-Met might cooperatively participate in the malignant progression of gastric cancer. In conclusion, MACC1 might serve as a useful molecular target for the diagnosis, treatment and prognosis of gastric cancer.

Metastasis-associated in colon cancer 1: A promising biomarker for the metastasis and prognosis of colorectal cancer

Colorectal cancer (CRC) is the fourth most frequent type of malignancy in the world. Metastasis accounts for >90% mortalities in patients with CRC. The metastasis-associated in colon cancer 1 (MACC1) gene has been identified as a novel biomarker for the prediction of metastasis and disease prognosis, particularly for patients with early-stage disease. Previous clinical studies demonstrated that MACC1 expression and polymorphisms in CRC tissues were indicators of metastasis, and that circulating transcripts in plasma were also significantly associated with the survival of patients. The present review describes the use of MACC1 beyond its utility in the clinic. By elucidating the upstream and downstream signal pathways of MACC1, the well-known mechanisms of MACC1-mediated cell proliferation, invasion, migration and epithelial-mesenchymal transition (EMT) are summarized, as well as the potential signaling pathways. Furthermore, the underlying mechanisms by which the overexpression of MACC1 causes cisplatin resistance are emphasized.

Targeting H19 by lentivirus-mediated RNA interference increases A549 cell migration and invasion

BACKGROUND

Lung cancer is one of the most common and a lethal malignancy in the world and non-small cell lung cancer (NSCLC) is the most usual type. H19 long non-coding RNA (lncRNA) plays essential roles in tumor development. But its role in tumor metastasis is still unclear.

MATERIALS AND METHODS

MACC1 RNAi and Lentivirus-mediated H19-specific shRNA was used to establish H19 stable knocking-down A549 cells. Transwell assays were performed to examine the effect of H19 knocking-down on A549 cells migration and invasion. The downstream signaling proteins targeted by H19 were also examined by western blot. AG1478 and U0126 were used as the inhibitor of EGFR and ERK1/2, respectively.

RESULTS

The knockdown of H19 increased the migration and invasion of A549 cells, and knockdown of metastasis-associated in colon cancer 1 (MACC1) decreased the migration and invasion of A549 cells. Furthermore, MACC1 protein targeted by H19 was upregulated as well as the downstream signaling proteins including epidermal growth factor receptor (EGFR), β-catenin, extracellular-signal-regulated kinase 1/2 (ERK1/2). Inhibited the expression of EGFR or ERK1/2 significantly decreased the migration and invasion of tumor cells.

CONCLUSION

Our findings showed that H19 functions as a suppressor of NSCLC and plays an important role in the migration and invasion of NSCLC. More importantly, H19 may regulate NSCLC metastasis through modulating cellular signaling pathway proteins related to cell proliferation and cell adhesion, including MACC1, EGFR, β-catenin and ERK1/2. These results put forward our understanding of the detailed mechanism of H19 lncRNA regulating the process of NSCLC metastasis.

Positive MACC1 expression correlates with invasive behaviors and postoperative liver metastasis in colon cancer

OBJECTIVE

Metastasis-associated in colon cancer-1 (MACC1), a new gene associated with primary and metastatic colon cancer, promotes tumor cell growth as well as the development of distant metastasis. The aim of this study is to investigate the expression of MACC1 protein in colon cancer and its association with clinicopathological parameters and postoperative liver metastasis.

MATERIALS AND METHODS

Expression of MACC1 protein was detected immunohistochemically in paraffin-embedded specimens of 96 cases of colon cancer. Relationship between MACC1 protein expression and clinicopathological parameters, postoperative liver metastasis were analyzed.

RESULTS

Immunohistochemistry examination showed that MACC1 protein expression was significantly more abundant in colon cancer tissues than in normal colon tissues (P = 0.038), Positive rate of MACC1 expression in colon cancer tissues was increased significantly in patients with lymph node metastases (P = 0.001) and higher T stages (P = 0.006). Postoperative live metastasis-free survival period was significantly longer in negative MACC1 expression group than that of positive MACC1 expression group (36.4 ± 2.85 vs. 28.6 ± 2.02 months, P = 0.014). Multivariate analysis showed that MACC1 expression level is an independent prognostic factor for postoperative live metastasis-free survival (95% confidence interval [CI] =1.32-3.38, P = 0.006).

CONCLUSIONS

Our results suggest that MACC1 expression level might play an important role in colon cancer invasion and MACC1 expression level is an independent biomarker for postoperative liver metastasis in patients with colon cancer.

MACC1 induces metastasis in ovarian carcinoma by upregulating hepatocyte growth factor receptor c-MET

Metastasis-associated in colon cancer 1 (MACC1) is a newly identified gene that has been shown to promote tumor cell invasion and metastasis. The present study investigated the effect of MACC1 downregulation on the biological characteristics of the ovarian cancer OVCAR3 cell line. In this study, MACC1 expression was blocked using the RNA interference technique. The downregulation of MACC1 mRNA and protein expression was confirmed using quantitative polymerase chain reaction and western blot analysis. The proliferative activity and adhesion rate of the cells were detected using cell counting kit-8 and a cell adhesion assay, while cell invasion was determined using a Matrigel invasion assay and migration capacity was observed using migration and wound-healing assays. A tube formation assay was also used to examine the angiogenic capacity of cells, and a luciferase assay was performed to assess whether MACC1 binds to the c-MET gene. The MACC1 mRNA and protein expression levels were significantly downregulated using sequence-specific small interfering RNA (siRNA). The inhibition of MACC1 expression markedly decreased the invasive, metastatic and angiogenic capacities of the cells, but only slightly inhibited growth and adhesion. In addition, a putative MACC1-binding site was identified in the 3′-untranslated region of c-MET. MACC1-siRNA was also found to significantly reduce the expression of the c-MET protein and a luciferase reporter assay confirmed that c-MET was the target gene of MACC1. These results demonstrated that the attenuation of MACC1 suppresses cell invasion and migration and that MACC1 may regulate cell metastasis through targeting the expression of c-MET. Inhibition of the function of MACC1 may represent a new strategy for treating ovarian cancer.