Chunyi Hao

CD44-positive cancer stem cells expressing cellular prion protein contribute to metastatic capacity in colorectal cancer

Cancer stem cells are implicated in tumor progression, metastasis, and recurrence, although the exact mechanisms remain poorly understood. Here, we show that the expression of cellular prion protein (PrPc, PRNP) is positively correlated with an increased risk of metastasis in colorectal cancer. PrPc defines a subpopulation of CD44-positive cancer stem cells that contributes to metastatic capacity. PrPc(+)CD44(+) colorectal cancer stem cells displayed high liver metastatic capability, unlike PrPc(-)CD44(+) stem cells, that was inhibited by RNAi-mediated attenuation of PrPc. Notably, administration of PrPc monoclonal antibodies significantly inhibited tumorigenicity and metastasis of colorectal cancer stem cells in mouse models of orthotopic metastasis. PrPc promoted epithelial to mesenchymal transition (EMT) via the ERK2 (MAPK1) pathway, thereby conferring high metastatic capacity. Our findings reveal the function of PrPc in regulating EMT in cancer stem cells, and they identify PrPc as candidate therapeutic target in metastatic colorectal cancer.

Expression of SATB1 Promotes the Growth and Metastasis of Colorectal Cancer

Special AT-rich sequence-binding protein-1 (SATB1) has been identified as a genome organizer that reprograms chromatin organization and transcription profiles. SATB1 promotes tumor growth and metastasis in breast cancer and is associated with poor prognosis in several cancer types. The association between SATB1 and colorectal cancer (CRC) has not been studied intensively. Therefore, this study aimed to investigate the effect of SATB1 on CRC growth and metastasis in vitro and in vivo and its correlation with overall survival and clinicopathological factors in CRC patients. Stable SATB1 knockdown and SATB1-overexpressing cell lines were established. SATB1 knockdown decreased cell growth, colony formation, migration, and invasion and increased apoptosis in CRC cells in vitro (p<0.05), whereas SATB1 overexpression had the opposite effect. SATB1 overexpression increased tumor growth and metastasis to lung and liver in vivo by using xenograft animal models (p<0.05). Thus, SATB1 promoted an aggressive CRC phenotype in vitro and in vivo. Immunohistochemical analysis of 560 CRC specimens showed that SATB1 expression was significantly higher in CRC tissues than in matched non-tumor mucosa (p<0.001). In addition, SATB1 expression was significantly higher in patients with poorly differentiated tumors, higher invasion depth, distant metastasis, and advanced TNM stage. SATB1-positive patients had a poorer prognosis than SATB1-negative patients, and SATB1 was identified as an independent prognostic factor for CRC (p = 0.009). Strikingly, we also evaluated SATB2 expression in CRC and found that SATB2 was more abundantly expressed in non-cancerous mucosa compared to colorectal cancer tissues (p<0.001). However, SATB2 expression had no influence on prognosis of CRC patients (p = 0.836). SATB1 expression was significantly associated with shorter survival time either in SATB2-positive patients or in SATB2-negative patients (p<0.001). In conclusion, our findings indicated an important role for SATB1 in CRC tumorigenesis and metastasis. Therefore, SATB1 may represent an important prognostic biomarker and therapeutic target for CRC.

Evaluation of Hepatic-Metastasis Risk of Colorectal Cancer upon the Protein Signature of PI3K/AKT Pathway

Liver is the most common organ of colorectal cancer (CRC) metastasis, and hepatic metastasis (HM) is regulated by complex protein network. Hence, we initiated a proteomic survey to seek interrelated multiplex markers related with HM. A total of 34 unique differential proteins were identified in the primary tumor tissues from 14 CRC patients with/without HM. A differential protein cluster, consisting of 17 proteins throughout PI3K/AKT pathway, was deduced and validated by Western blot. A three-protein signature elicited from the protein cluster, phosphorylated IkappaBalpha, TNFalpha and MFAP3L, was detected by immunohistochemistry on 105 pairs of CRC and normal samples. The positive protein signature was specifically correlated with HM (P < 0.001), and classified the HM risk of CRC patients with high sensitivity (92.85 +/- 4.87%) and specificity (94.94 +/- 2.5%). The high-risk group had significantly decreased overall survival (P < 0.001). Furthermore, RKO and HT29, two colon cancer cells with different expression status of the protein signature, were used to construct the nude mouse model of HM. And the HM occurrence of RKO cell (4/5) was dramatically higher than that of HT29 cell (1/5). Therefore, the protein signature derived from PI3K/AKT pathway is likely a promising multiplex biomarker for HM of CRC.

MFAP3L activation promotes colorectal cancer cell invasion and metastasis

An abundance of microfibril-associated glycoprotein 3-like (MFAP3L) significantly correlates with distant metastasis in colorectal cancer (CRC), although the mechanism has yet to be explained. In this study, we observed that MFAP3L knock-down resulted in reduced CRC cell invasion and hepatic metastasis. We evaluated the cellular location and biochemical functions of MFAP3L and found that this protein was primarily localized in the nucleus of CRC cells and acted as a protein kinase. When EGFR translocated into the nucleus upon stimulation with EGF, MFAP3L was phosphorylated at Tyr287 within its SH2 motif, and the activated form of MFAP3L phosphorylated ERK2 at Thr185 and Tyr187. Moreover, the metastatic behavior of CRC cells in vitro and in vivo could be partially explained by activation of the nuclear ERK pathway through MFAP3L phosphorylation. Hence, we experimentally demonstrated for the first time that MFAP3L likely participates in the nuclear signaling of EGFR and ERK2 and acts as a novel nuclear kinase that impacts CRC metastasis.

PTK7 overexpression in colorectal tumors: Clinicopathological correlation and prognosis relevance

Colorectal cancer (CRC) has one of the highest mortality rates in the worldwide and its incidence has been increasing in recent years. Protein tyrosine kinase-7 (PTK7) is an inactive member of receptor protein tyrosine kinase (RPTK)-like molecules, which is involved in tumorigenesis of a variety of cancers. Our study aimed to investigate expression of PTK7 in colorectal tumors (including benign adenomas and malignant carcinomas), and its potential function in tumorigenesis and prognosis. A total of 209 CRC patients and 28 colonic adenoma patients were included in this study. Reverse transcription polymerase chain reaction (RT-PCR) and quantitative real-time PCR were performed in 14 pairs of fresh frozen tissues to evaluate mRNA expression of PTK7. Expression of PTK7 protein in 209 CRC tissues with paired non-cancerous mucosa and 28 adenoma specimens were tested using immunohistochemistry. The expression difference and its correlation with clinicopathological features and overall survival were assessed by SPSS statistics (version 22). P<0.05 was considered significant. RT-PCR and quantitative real-time PCR showed a higher expression of PTK7 mRNA in CRC compared with non-tumorous mucosa (4.87±3.71 vs. 1.33±1.05; P<0.001). PTK7 expression was significantly higher in adenoma (75%) and CRC (68.3%) than in non-tumorous mucosa (P<0.001). PTK7 expression was correlated with tumor differentiation (P=0.027), lymph node metastasis (P=0.005), distant metastasis (P=0.001) and TNM stage (P=0.028) of CRC patients. Significant correlation between PTK7 overexpression and favorable overall survival of CRC patients was observed (P=0.005). Therefore, it may act as a candidate biomarker to predict the occurrence and prognosis of colorectal tumor.

Suppression of CD26 inhibits growth and metastasis of pancreatic cancer

CD26/DPPIV is a glycosylated transmembrane type II protein and has a multitude of biological functions, while its impact on the malignant phenotypes of cancer cells has not been fully understood. This study aimed to investigate the effect of CD26 on growth and metastasis of pancreatic cancer cells in vitro and in vivo. We found in this study that CD26 expression was higher in cell lines that derived from the metastatic sites than those from the primary tumor sites. In specimens of pancreatic cancer patients, CD26 expression was higher in cancerous tissues than in paired normal tissues. In in vitro experiments, knockdown of CD26 expression inhibited cell growth, migration, invasion, colony formation, and increased cell apoptosis of pancreatic cancer cells. Knockdown of CD26 also decreased tumor growth and liver metastasis in vivo by using xenograft animal models. Suppression of CD26 could inhibit expression of epithelial-mesenchymal transition (EMT) regulatory genes. Our results indicated that CD26 may represent a new therapeutic target for pancreatic cancer.

Elevated serum CD26 level is associated with metastasis and post-operation survival in pancreatic cancer patients

Background: It has been proved that soluble CD26 (sCD26) has a close relationship with several types of cancers, while its level in pancreatic cancer has not been well established. Methods: In this study, enzyme-linked immunosorbent assay (ELISA) was applied to test the serum concentration of sCD26 in a total of 148 patients with different pancreatic diseases, including 92 pancreatic ductal adenocarcinoma (PDAC) patients. The correlation between sCD26 level and the clinicopathological features as well as post-operation survival of PDAC patients was also analyzed. Results: In this cohort, the average sCD26 concentration in healthy donors was 361.30±154.64 µg/L, while it varied in different types of pancreatic diseases. The preoperative sCD26 concentration of PDAC patients was 426.36±207.62 µg/L, which was higher than that in healthy donors (P=0.048) and closely related with tumor location, size, distant metastasis, tumor stage and post-operation survival time. But after operation, the serum concentration decreased to 243.44±113.90 µg/L in PDAC patients. Conclusions: The findings of this study have unveiled the concentrations of sCD26 in pancreatic diseases, and correlations between increased sCD26 level and favorable clinicopathological features as well as post-operation survival in PDAC patients were also detected.

Fusobacterium nucleatum infection is correlated with tumor metastasis and postoperative survival of colorectal cancer patients in China

Background: In western patients, the association of Fusobacterium nucleatum ( F. nucleatum ) with colorectal carcinoma (CRC) has been established, but the underlying mechanism remains unclear. There is no report about F. nucleatum infection status and its potential role in CRC patients in China. This study aimed to evaluate infection status and infection load of F. nucleatum and its correlation with clinicopathological features and prognosis of CRC patients in China. Methods: Fresh tumor and adjacent normal mucosa tissues were obtained at surgery from 152 CRC patients, and then DNA was assayed for infection of F. nucleatum by quantitative PCR. Then the association of infection with clinicopathological features and prognosis was evaluated. In addition, MMP9, MMP11, CD45RO and FOXP3 expression levels was assessed by immunohistochemistry to explore the potential role of F. nucleatum . Results: The infection rate of F. nucleatum in CRC tissues was significantly higher than that in adjacent normal tissues (77.6% vs . 57.2%, P<0.001), and median F. nucleatum copy number was also significantly higher in CRC tissues than in adjacent normal tissues (87 vs . 37, P<0.001). F. nucleatum infection of tumor tissues was related with poorer tumor differentiation (P<0.001), deeper tumor invasion (P<0.001), lymph node metastasis (P=0.01), distant metastasis (P=0.001) and advanced TNM stage (P=0.034). Specimens with higher infection load contained fewer CD45RO + T lymphocytes and more FOXP3 + regulatory T lymphocytes than those with lower infection load. And high-copy group had a poorer postoperative survival than the low-copy group (P=0.027). In the subset of CRC patients with F. nucleatum infection, tumor stage and F. nucleatum infection were independent prognostic factors. Advanced tumor stage and high-load infection were correlated poorer prognosis (P=0.023 and 0.032, respectively). Conclusions: Infection rate and load of F. nucleatum are higher in carcinoma tissues than in adjacent normal tissues from CRC patients in Chian. F. nucleatum infection was correlated with tumor metastasis and overall postoperative survival of colorectal cancer patients, so it can help to improve prevention, diagnosis and treatment of CRC in China.

A novel scoring system to predict ascites development post hepatectomy for BCLC stage B hepatocellular carcinoma

Background: To develop a novel scoring system to predict the development of post-operative ascites by analyzing clinicopathological characteristics and risk factors of BCLC stage B hepatocellular carcinoma. Methods: Prospective analysis was performed on consecutive patients with BCLC stage B hepatocellular carcinoma, who underwent hepatectomy from January 2005 to December 2014. Results: A total of 181 patients were enrolled, of whom 34.3% (62/181) developed post-operative ascites. Comparing with patients without ascites, patients who developed ascites had longer drain placement, more incidence of pleural effusion, more incidence of intra-abdominal infection and longer inpatient stay. All differences were statistically significant (P Conclusions: The development of post-operative ascites was associated with various clinicopathological factors. The scoring system, which incorporates these factors, provided a valuable means for predicting the development of post-operative ascites. Early identification of these at-risk patients might help to improve their perioperative outcome.

Diagnostic and prognostic value of KRAS mutations in circulating pancreatic ductal adenocarcinoma tumor DNA

Background: Pancreatic ductal adenocarcinoma (PDAC) is the most common type of pancreatic tumor and one of the most malignant tumors worldwide. Circulating tumor DNA (ctDNA) has significant diagnostic and prognostic value for cancer patients. Methods: Surgical specimens and plasma samples were obtained from a total of 35 patients with PDAC at the Peking University Cancer Hospital between June 2016 and May 2017. To investigate KRAS mutations (G12R, G12V or G12D) in plasma ctDNA, digital polymerase chain reaction (PCR) was performed on samples obtained from PDAC patients before and after surgical resection. Results: KRAS mutations (G12R, G12V or G12D) between surgical tissue DNA (tDNA) and preoperative plasma ctDNA (pre-ctDNA) were consistent in 27 of 35 samples (77.1%, kappa index =0.397, P=0.003). Moreover, pre-ctDNA and postoperative plasma ctDNA (post-ctDNA) showed statistically significant associations with CA19-9 levels before surgery (P=0.027 and P=0.003, respectively). In addition, the Kaplan-Meier univariate and Cox multivariate analysis revealed that pre-ctDNA (G12V), post-ctDNA (G12V), or pre-post ctDNA (G12V, G12D) might be independent prognostic factors for overall survival (OS) and progression-free survival (PFS). Conclusions: Analysis of pre-ctDNA, post-ctDNA, and pre-post ctDNA showed high PDAC diagnostic and prognostic potential in patients.