PTX1(ERGIC2)–VP22 Fusion Protein Upregulates Interferon-β in Prostate Cancer Cell Line PC-3

Novel methylated DNA markers accurately discriminate Lynch syndrome associated colorectal neoplasia

Aim:

Acquired molecular changes in Lynch syndrome (LS) colorectal tumors have been largely unstudied. We identified methylated DNA markers (MDMs) for discrimination of colorectal neoplasia in LS and determined if these MDMs were comparably discriminant in sporadic patients.

Patients & methods:

For LS discovery, we evaluated DNA from 53 colorectal case and control tissues using next generation sequencing. For validation, blinded methylation-specific PCR assays to the selected MDMs were performed on 197 cases and controls.

Results:

OPLAH was the most discriminant MDM with areas under the receiver operating characteristic curve ≥0.97 for colorectal neoplasia in LS and sporadic tissues. ALKBH5, was uniquely hypermethylated in LS neoplasms.

Conclusion:

Highly discriminant MDMs for colorectal neoplasia in LS were identified with potential use in screening and surveillance.

PUF60/AURKA Axis Contributes to Tumor Progression and Malignant Phenotypes in Bladder Cancer

Abnormal expression or mutation of RNA splicing proteins are widely observed in human cancers. Here, we identified poly(U) binding splicing factor 60 (PUF60) as one of the most differentially expressed genes out of 97 RNA splicing proteins between normal and bladder cancer tissues by bioinformatics analysis of TCGA bladder cancer expression data. The expression of PUF60 was significantly higher in tumor tissues, while high PUF60 expression was associated with malignant phenotypes of bladder cancer and shorter survival time. Moreover, we identified aurora kinase A (AURKA) as a new downstream target of PUF60 in bladder cancer cells. PUF60 knockdown significantly inhibited cell viability and colony formation capacity in bladder cancer cells, whereas AURKA overexpression reversed this inhibition effect. Overexpression of PUF60 significantly promoted cell viability and colony formation in bladder cancer cells, while treatment with AURKA specific inhibitor reversed this promotive effect. Mechanistically, PUF60 specifically bound to the AURKA promoter, thereby activating its transcription and expression. Furthermore, we showed that there was a significant positive correlation between PUF60 and AURKA expression in bladder cancer tissues, and PUF60 and AURKA expression contributed to tumor progression and malignant phenotypes in the patients with bladder cancer. Collectively, these results indicate that the PUF60/AURKA axis plays a key role in regulating tumorigenesis and progression of bladder cancer, and may be a potential prognostic biomarker and therapeutic target for bladder cancer patients.

Characterization of a prognostic four‑gene methylation signature associated with radiotherapy for head and neck squamous cell carcinoma

Head and neck squamous cell carcinoma (HNSCC) remains one of the most common malignancies associated with poor prognosis. DNA methylation has emerged as an important mechanism underlying the radio-resistance of tumors. Prognostic biomarkers based on radiotherapy-related aberrant DNA methylation are limited. Methylation profiles of 388 patients with HNSCC were acquired from The Cancer Genome Atlas (TCGA) portal. Genes with differentially methylated CpG sites (DMGs) were screened between patients with a favorable and poor prognosis with or without radiotherapy. A weight gene co-methylation network was constructed using a Weighted Gene Co-expression Network Analysis (WGCNA) package. A lasso Cox-PH model was used to identify the optimal panel of genes with the ability to predict survival in these patients. Prognostic performance of the multi-gene methylation signature was assessed in a training set and confirmed in a validation set. A total of 976 DMGs were observed between favorable and poor prognostic samples. Four DMG-enriched co-methylation modules were identified. A four-gene methylation signature was determined by the lasso Cox-PH model that consisted of ZNF10, TMPRSS12, ERGIC2, and RNF215. The risk score based on the four-gene signature was able to divide the training or validation set into two risk groups with significantly different overall survival. Thus, the present study revealed a radiotherapy-related four-gene methylation signature to predict survival outcomes of patients with HNSCC, providing candidate therapeutic targets for novel therapy against HNSCC. However, substantial validation experiments are required.

Silenced PITX1 promotes chemotherapeutic resistance to 5-fluorocytosine and cisplatin in gastric cancer cells

Resistance to chemotherapeutic drugs leads to a poor prognosis in gastric cancer (GC). The present study aimed to assess the association between pituitary homeobox paired homeodomain transcription 1 (PITX1) expression and the sensitivity of GC cells to the chemotherapeutic drugs 5-fluorouracil (5-FU) and cisplatin (CDDP). In the present study, the gastric cancer cell lines GES-1, AGS, BGC-823, MCG-803 and SGC-7901 were used. The expression of PITX1 was determined via reverse transcription-quantitative polymerase chain reaction in GC cell lines. AGS and BGC-823 cells, which exhibit a decreased PITX1 expression, were transfected with a PITX1 cDNA construct and its control vector. MCG-803 and SGC-7901 cells, which exhibit an increased PITX1 expression, were transfected with siRNA against PITX1 and its control scramble sequence. A Cell Counting kit-8 assay was performed to determine the impact of PITX1 expression on the sensitivity of GC cells to 5-FU and CDDP. The Cancer Genome Atlas database was used to analyze the expression of PITX1 with GC prognosis in the Asian population and to assess the potential mechanism of PITX1 in 5-FU and CDDP resistance. The results revealed that the overexpression of PIXT1 increased the sensitivity of GC cells to 5-FU/CDDP. The combination of 5-FU/CDDP and PITX1 overexpression also reduced the proliferation of GC cells. Additionally, PIXT1 knockdown decreased the sensitivity of GC cells to 5-FU/CDDP. TCGA data revealed that a lower expression of PITX1 is exhibited in Asian GC patients than in normal individuals. GC patients with a lower expression of PITX1 had a poor prognosis. The expression of PITX1 affected the sensitivity of GC cells to 5-FU/CDDP, indicating that PITX1 may increase the efficacy of treatment in GC patients.

PITX1 is a novel predictor of the response to chemotherapy in head and neck squamous cell carcinoma

The pituitary homeobox 1 (PITX1) protein is essential for developmental processes in humans. Previously, PITX1 was identified as a possible tumor suppressor gene in various types of human carcinoma. However, the association between PITX1 and human head and neck squamous cell carcinoma (HNSCC) remains to be elucidated. Immunohistochemical analysis was performed to examine the expression levels of PITX1 in 47 cases of HNSCC, and in 4 control cases. The expression of p53 was also examined in these cases. The labeling indices (LIs) were calculated, and the correlations between clinical factors (chemosensitivity, prognosis and the degree of differentiation) and the LIs were assessed. The PITX1 LI in HNSCC was 27.4±14.5%, which was significantly lower compared with the LIs of the control samples: 76.9±6.97% (P<0.05). Additionally, the PITX1 LIs were 39.9±6.2, 26.9±16.9 and 24.2±11.8% in the complete response (CR), partial response (PR), stable disease or progressive disease (SD/PD) groups, respectively. The PITX1 LI in the CR group revealed the highest result between the all groups, and it was significantly greater compared with that in the SD/PD group (P<0.01). The p53 LIs were 24.5±19.9, 25.7±16.9 and 19.8±13.8 in the CR, PR and SD/PD groups, respectively (P>0.05). Neither the PITX1 nor the p53 LIs were a statistically significant indicator of the prognosis. PITX1 is a candidate tumor suppressor gene and a possible predictive biomarker of chemosensitivity of human HNSCC.

PITX1 is a reliable biomarker for predicting prognosis in patients with oral epithelial dysplasia

Paired-like homeodomain 1 (PITX1) genes are essential in human development. In the present study, PITX1 protein expression was evaluated in human normal oral mucosa, oral epithelial dysplasia and oral squamous cell carcinoma (OSCC), with the aim of examining the expression patterns of these critical genes during the multi-stage transformation of oral epithelial dysplasia to OSCC. PITX1 and Ki-67 expression were assessed by immunohistochemistry in 26 individuals with normal oral mucosa, 106 patients with oral epithelial dysplasia and 97 OSCC patients. The labeling indices (LIs) of PITX1 and Ki-67 were calculated and their correlation with the incidence of malignancy was evaluated. The PITX1 LI of the dysplasia specimens was significantly lower than that of the normal oral mucosa samples, but significantly higher than that of the OSCC samples. The oral epithelial dysplasia patients that exhibited low PITX1 expression showed a significantly higher incidence of malignant transformation than those exhibiting high PITX1 expression, regardless of the histological grades of their oral epithelial dysplasias. On the other hand, no correlation was observed between the Ki-67 LI and the incidence of malignancy. These results suggested that PITX1 suppression is associated with malignant transformation in the oral epithelium and that PITX1 expression may serve as a novel biomarker for predicting prognosis in oral epithelial dysplasia.

Characterization of a variant of ERGIC2 transcript

ERGIC2 (formerly known as PTX1) is a gene identified by subtractive hybridization on the basis that it is expressed in normal human prostate, but not in prostate carcinoma. It is unrelated to the gene encoding pituitary homeobox protein (Ptx1 or Pitx1), which regulates pituitary hormone gene expression. Based on sequence homology with the yeast Erv41 protein, it is suggested that the ERGIC2 protein is an endoplasmic reticulum (ER) resident protein involved in protein trafficking between the ER and Golgi intermediate compartment (ERGIC) and cis-Golgi. However, studies from our laboratory and others have shown that it may have other functions. In this study, we have identified a variant ERGIC2 transcript with a four base deletion at the junction of exons 8-9, resulting in frame shift after codon #189. As a result, a truncated protein of 215 residues (24.5 kDa) is predicted as compared with the 377-residue (42.6 kDa) wild-type (WT) protein. The truncated variant ERGIC2 protein loses 45% of the luminal domain and the transmembrane domain near the C-terminus, and this effectively abrogates its function as the ERGIC-Golgi protein transport shuttle. The variant, like the WT protein, was found to upregulate the heme oxygenase 1 gene, suggesting that it may be involved in the oxidative stress pathway.

Mesenchymal stem cells modified to express interferon-β inhibit the growth of prostate cancer in a mouse model

OBJECTIVE

This study investigated use of mesenchymal stem cells (MSCs) genetically engineered to produce interferon-β (IFN-β) as a gene delivery system to treat prostate cancer in an animal model.

METHODS

To measure the effects on tumour cell growth in vitro, IFN-β-producing MSCs (IFN-β-MSCs) were co-cultured with the prostate cancer cell line PC-3. The in vivo migration of intravenously injected fluorescently-labelled MSCs to healthy tissues and PC-3 xenograft tumours grown in immuno-deficient mice was determined by fluorescence microscopy. The antitumour effects of intravenously injected IFN-β-MSCs on PC-3 xenograft growth and animal survival were also investigated.

RESULTS

IFN-β-MSCs inhibited the growth of PC-3 cells in vitro. Fluorescently-labelled MSCs migrated to the margins and centre of tumour masses but not into healthy tissues. Intravenously injected IFN-β-MSCs significantly reduced PC-3 xenograft tumour weight and increased animal survival compared with controls.

CONCLUSIONS

Intravenously injected IFN-β-MSCs inhibited PC-3 xenograft growth. This could be an effective gene delivery system for treatment of solid human tumours.