Tongjun Liu

miRNA-22 suppresses colon cancer cell migration and invasion by inhibiting the expression of T-cell lymphoma invasion and metastasis 1 and matrix metalloproteinases 2 and 9

Emerging evidence has demonstrated the altered expression of mRNAs in cancer development and progression. In this study, the precise role of miRNA-22 (miR-22) in colon cancer cells was investigated. Upon transfection with a miR-22 expression vector, the viability of HCT-116 human colon cancer cells was significantly reduced and tumor cell migration and invasion capacity were also suppressed. Computational in silico analysis predicted that T-cell lymphoma invasion and metastasis 1 (TIAM1) is a target gene of miR-22. This was confirmed by qRT-PCR and western blotting, which showed that miR-22 expression inhibited TIAM1 mRNA and protein expression, respectively. In addition, the expression of pro-invasive gene matrix metalloproteinases 2 and 9 (MMP-2 and MMP-9) and pro-angiogenic protein vascular endothelial growth factor (VEGF) were also reduced by miR-22 expression. Collectively, these data suggest that miR-22 may act as a tumor suppressor in colon cancer, most likely by targeting TIAM1 expression.

PD‑0332991 induces G1 arrest of colorectal carcinoma cells through inhibition of the cyclin‑dependent kinase‑6 and retinoblastoma protein axis

Preclinical and clinical studies have demonstrated the anticancer activity of PD-0332991, a selective cyclin-dependent kinase 4/6 (CDK4/6) inhibitor, in the treatment of various types of cancer in a retinoblastoma protein (RB)-dependent manner. However, it remains unclear whether CDK4, CDK6 or both are required for RB phosphorylation in colorectal carcinoma and thus PD-0332991 can be used to target this CDK-RB axis for the cancer therapy. The aim of this study was to determine whether CDK4, CDK6 and phosphorylated RB proteins were overexpressed in colorectal carcinoma tissues as compared to matched normal colorectal tissues. The results showed that knockdown of CDK6 but not CDK4 reduced RB phosphorylation and inhibited carcinoma cell growth. Thus, CDK6 plays a critical role in RB phosphorylation and cancer growth. PD-0332991 treatment blocked RB phosphorylation and inhibited cell growth through the induction of G1 arrest of colorectal carcinoma cells. The results demonstrated that, by targeting of CDK6-RB axis, PD-0332991 may prove to be a novel therapeutic agent in treating colorectal carcinoma.

Combination of mTOR and EGFR Kinase Inhibitors Blocks mTORC1 and mTORC2 Kinase Activity and Suppresses the Progression of Colorectal Carcinoma

Mammalian target of rapamycin complex 1 and 2 (mTORC1/2) are overactive in colorectal carcinomas; however, the first generation of mTOR inhibitors such as rapamycin have failed to show clinical benefits in treating colorectal carcinoma in part due to their effects only on mTORC1. The second generation of mTOR inhibitors such as PP242 targets mTOR kinase; thus, they are capable of inhibiting both mTORC1 and mTORC2. To examine the therapeutic potential of the mTOR kinase inhibitors, we treated a panel of colorectal carcinoma cell lines with PP242. Western blotting showed that the PP242 inhibition of mTORC2-mediated AKT phosphorylation at Ser 473 (AKTS473) was transient only in the first few hours of the PP242 treatment. Receptor tyrosine kinase arrays further revealed that PP242 treatment increased the phosphorylated epidermal growth factor receptor (EGFR) at Tyr 1068 (EGFRT1068). The parallel increase of AKTS473 and EGFRT1068 in the cells following PP242 treatment raised the possibility that EGFR phosphorylation might contribute to the PP242 incomplete inhibition of mTORC2. To test this notion, we showed that the combination of PP242 with erlotinib, an EGFR small molecule inhibitor, blocked both mTORC1 and mTORC2 kinase activity. In addition, we showed that the combination treatment inhibited colony formation, blocked cell growth and induced apoptotic cell death. A systemic administration of PP242 and erlotinib resulted in the progression suppression of colorectal carcinoma xenografts in mice. This study suggests that the combination of mTOR kinase and EGFR inhibitors may provide an effective treatment of colorectal carcinoma.

The association of TP53 mutations with the resistance of colorectal carcinoma to the insulin-like growth factor-1 receptor inhibitor picropodophyllin

BackgroundThere is growing evidence indicating the insulin-like growth factor 1 receptor (IGF-1R) plays a critical role in the progression of human colorectal carcinomas. IGF-1R is an attractive drug target for the treatment of colon cancer. Picropodophyllin (PPP), of the cyclolignan family, has recently been identified as an IGF-1R inhibitor. The aim of this study is to determine the therapeutic response and mechanism after colorectal carcinoma treatment with PPP.MethodsSeven colorectal carcinoma cell lines were treated with PPP. Following treatment, cells were analyzed for growth by a cell viability assay, sub-G1 apoptosis by flow cytometry, caspase cleavage and activation of AKT and extracellular signal-regulated kinase (ERK) by western blot analysis. To examine the in vivo therapeutic efficacy of PPP, mice implanted with human colorectal carcinoma xenografts underwent PPP treatment.ResultsPPP treatment blocked the phosphorylation of IGF-1R, AKT and ERK and inhibited the growth of TP53 wild-type but not mutated colorectal carcinoma cell lines. The treatment of PPP also induced apoptosis in TP53 wild-type cells as evident by the presence of sub-G1 cells and the cleavage of caspase-9, caspase-3, DNA fragmentation factor-45 (DFF45), poly (ADP-ribose) polymerase (PARP), and X-linked inhibitor of apoptosis protein (XIAP). The loss of BAD phosphorylation in the PPP-treated TP53 wild type cells further suggested that the treatment induced apoptosis through the BAD-mediated mitochondrial pathway. In contrast, PPP treatment failed to induce the phosphorylation of AKT and ERK and caspase cleavage in TP53 mutated colorectal carcinoma cell lines. Finally, PPP treatment suppressed the growth of xenografts derived from TP53 wild type but not mutated colorectal carcinoma cells.ConclusionsWe report the association of TP53 mutations with the resistance of treatment of colorectal carcinoma cells in culture and in a xenograft mouse model with the IGF-1R inhibitor PPP. TP53 mutations often occur in colorectal carcinomas and could be used as a biomarker to predict the resistance of colorectal carcinomas to the treatment by this IGF-1R inhibitor.

Simultaneous targeting of EGFR and mTOR inhibits the growth of colorectal carcinoma cells

Epidermal growth factor receptor (EGFR) is highly expressed in colorectal carcinomas and, as a result, it leads to the activation of downstream mammalian target of rapamycin (mTOR) kinase pathways for cancer growth and progression. Clinical and preclinical studies, however, have shown that inhibition of epidermal growth factor receptor (EGFR) and mammalian target of rapamycin (mTOR) alone is not sufficient to treat colorectal carcinomas. In search of effective combination therapies, we show here that simultaneous targeting of EGFR with its inhibitor, erlotinib and mTOR with its inhibitor, rapamycin inhibits the phosphorylation and activation of downstream phosphatidylinositol 3-kinase (PI3K), Akt, mTOR and extracellular-signal-regulated kinase 1/2 (Erk1/2) pathways, resulting in the inhibition of cell cycle progression and the growth of both KRAS wild-type and mutated colorectal carcinoma cells. This study has demonstrated the principle that the combination of erlotinib and rapamycin may provide an effective therapy for colorectal carcinomas.

Analysis of circulating tumor cells in colorectal cancer liver metastasis patients before and after cryosurgery.

ABSTRACT In this study, we determined the number of peripheral blood circulating tumor cells (CTCs) pre- and post-cryosurgery in patients with colorectal cancer liver metastasis as a reference for understanding the relevance of any changes to the efficacy of cryosurgery. CTC numbers and CTC-related gene expression were measured in the peripheral blood of 55 patients with colorectal liver metastasis at 1 day before and 7 and 30 d after cryoablation using magnetic activated cell sorting (MACS) and fluorescence activated cell sorting (FACS) combined with real-time quantitative PCR (RT-qPCR). The number of CTCs decreased significantly with postoperative time (P < 0.01). Delta cycle threshold values for the CTC-related genes CEA, Ep-CAM, CK18 and CK19 increased significantly after cryoablation. Furthermore, the expression of CEA, Ep-CAM, CK18 and CK19 decreased significantly with time after cryoablation (P < 0.01). RT-qPCR and FACS combined with MACS has significant diagnostic and prognostic value for evaluating the efficacy of cryosurgery in patients with advanced colorectal cancer.

Apelin13/APJ promotes proliferation of colon carcinoma by activating Notch3 signaling pathway

Background The link between Apelin (APL)/APL receptor (APJ) and Jagged (JAG)/Notch signaling pathways in colorectal cancer (CRC) has been poorly investigated. APL/APJ system, a potent angiogenic factor, is up-regulated in a variety of cancers. It contributes to tumor angiogenesis, and correlates with progression of malignancy. JAG/Notch signaling also contributes to progression, proliferation and metastasis of multiple cancers, including CRC. Here we tested the hypothesis that APL/APJ system promotes CRC proliferation by up-regulating Notch3, thus allowing further binding of JAG1 to Notch3. Materials and Methods We used a variety of methods including Western blot, RT-qPCR, gene silencing, ELISA, immunofluorescence staining, to investigate the interaction between APL/APJ system and Notch3 signaling pathway in both surgically-resected specimens and CRC cell line LS180. Results We show that the expression of APL13, APJ, and Notch3 is elevated in CRC. We further demonstrate that APL13 can be secreted into culture media of LS180 cells, suggesting the existence of autocrine loop in CRC. Moreover, we found that APL13 stimulated expression of Notch3. Finally, we found that inhibition of either APJ or Notch3 prevents proliferation of LS180 cells. Conclusions Our results suggest that APL13/APJ and JAG1/Notch3 signaling pathways are linked in CRC. These findings provide a new direction to the efforts targeting effective therapeutic and management approaches in the treatment of CRC.

Evaluation of the safety of irreversible electroporation on the stomach wall using a pig model

The aim of the present study was to evaluate the effects of irreversible electroporation (IRE) on the stomach wall following the direct application of IRE onto the organ surface. IRE ablation was performed in 8 Tibetan mini-pigs, which were randomly assigned into two groups based on their ablated areas: Group A, gastric cardia, fundus of stomach, gastric body and group B, lesser gastric curvature, greater gastric curvature, stomach pylorus. Two IRE needles were placed in the space between the stomach wall and the liver (not inserted into the stomach tissue), and three lesions were created in each pig. Serum aminotransferase and white blood cell (WBC) levels were measured. Gastroscopy and endoscopic ultrasonography were performed. From each group, 2 pigs were sacrificed on day 7 post-IRE; the remaining pigs were sacrificed on day 28 post-IRE. There were no signs of perforation on the stomach wall. Serum aminotransferase and WBC levels increased in both groups on day 1 post-IRE and decreased gradually thereafter. The gastroscopy procedure revealed oval ulcers on day 7 post-IRE and smaller ulcers on day 28 post-IRE. Transmural necrosis, inflammation and fibrosis were observed at 7 days post-IRE. Healing ulcers were observed at 28 days post-IRE. In conclusion, IRE ablation caused damage to the stomach wall; however, IRE did not induce any perforation.

Pain Analysis in Patients with Pancreatic Carcinoma: Irreversible Electroporation versus Cryoablation

The aim of this article is to evaluate and compare the postprocedure pain in patients with pancreatic carcinoma treated with irreversible electroporation (IRE) and cryoablation (CRYO). We compared 22 patients with 22 lesions in pancreas treated with IRE and 26 patients with 27 lesions treated with cryosurgery. All the patients in the two groups were under celiac plexus block (CPB) treatment to alleviate the postprocedure pain. A numerical rating scale (VAS) consisting of 11-point scales and the 24 h total hydromorphone use were recorded for the analysis of the pain level in the patients who underwent these two technologies separately. Other parameters, such as the complications and the ECOG performance status, were also noted. Statistical analysis was performed by Fishers exact test, the Chi-square test, and Students t-test. All the pancreatic carcinoma patients in our study were reported to have postprocedure pain in the two groups. But there was no significant difference in the mean pain score (4.95 (IRE) versus 4.85 (CRYO); P = 0.52) and 24 h total hydromorphone use (3.89 mg (IRE) versus 3.97 mg (CRYO); P = 0.30). IRE is comparable to cryotherapy in the amount of pain that patients with pancreatic carcinoma experience.

Ectopic pancreatic tissue in the wall of the small intestine: Two rare case reports

Rationale: Ectopic pancreas, which is a kind of rare congenital disease, forms during embryonic development. It can occur throughout the whole gastrointestinal tract, but has a low tendency to develop in the wall of the small intestine. It is easy for patients with ectopic pancreases to be misdiagnosed because the symptoms are untypical and can vary. Patient concerns: In the present study, we reported two rare cases of ectopic pancreatic tissue in the wall of the small intestine, which presented with obvious abdominal pain and distention. Diagnosis: The laboratory tests and computed tomography (CT) scans didn’t reveal any evidence of ectopic pancreas. Interventions: The two patients received small intestine masses resection and intestinal anastomosis. Outcomes: During surgery, an intestinal mass with a diameter of 4.0 cm was found in the first patient. An intestinal mass with a diameter of 0.8 cm, jejunum perforation, and diffuse peritonitis were found in the second patient. Histological analyses of the dissected intestinal masses confirmed them as ectopic pancreatic tissue. Interestingly, for the second patient, the intestinal perforation and diffuse peritonitis were not induced by the ectopic pancreas, but by a jujube pit that was found in the perforated site of the intestine. Lessons: Our study demonstrated that an ectopic pancreas should be considered in cases of untypical abdominal symptoms with intestinal masses.