Nuclear-cytoplasmic translocation of SQSTM1/p62 protein enhances ESCC cell migration and invasion by stabilizing EPLIN expression.

Esophageal squamous cell carcinoma (ESCC) is an aggressive malignant disease with a poor prognosis. We previously found that p62 presented a marked nuclear-cytoplasmic translocation in ESCC cells as compared that in normal esophageal epithelial cells, but its effects on ESCC cells remain unclear. This study aims to clarify the impacts of different cellular localization of p62 on the function of ESCC cells and the underlying molecular mechanisms. We here demonstrated that cytoplasmic p62 enhances the migration and invasion abilities of esophageal cancer cells, whereas nuclear p62 has no effect. We further explored the interaction protein of p62 by using GST pull-down experiment and identified EPLIN as a potential protein interacting with p62. In addition, reducing EPLIN expression significantly inhibited the migration and invasion of ESCC cells, which were rescued when EPLIN expression was restored after the p62 knockdown. At a molecular level, p62 in cytoplasm positively regulated the expression of EPLIN via enhancing its protein stability. Data from the TCGA and GEO database displayed a significant up-regulation of EPLIN mRNA expression in ESCC tissues compared with corresponding paired esophageal epithelial samples. Our findings present evidence that the nuclear-cytoplasmic translocation of p62 protein contributes to an aggressive malignancy phenotype, providing candidate molecular biomarkers and potential molecular targets for the diagnosis and treatment of ESCC.

Dysregulation of CXCL14 promotes malignant phenotypes of esophageal squamous carcinoma cells via regulating SRC and EGFR signaling.

The present study was to identify abnormal methylation genes implicated in esophageal squamous cell carcinoma (ESCC). Genomic methylation alterations in ESCC tissues were analyzed using laser-microdissection and whole-genome bisulfite sequencing. CXCL14 promoter was frequently hypermethylated in ESCC tissues. The correlation of CXCL14 hypermethylation status and the mRNA and protein expression levels were validated using nested methylation-specific PCR (nMS-PCR), RNAscope in situ hybridization (RISH) and Western blot. RISH results showed completely negative CXCL14 expression in 34.3% (34/99) ESCC, compared with those in the basal layer cells of normal epithelia. Low expression of CXCL14 was more present in patients with lower differentiation. The anticancer role of CXCL14 has been commonly associated with immune regulation in the literature. Here, we observed by functional analysis that CXCL14 can also act as a tumor suppressor in ESCC cells. 5-Aza-dC treatment suppressed CXCL14 methylation and up-regulated the expression of CXCL14. Ectopic expression of CXCL14 suppressed the proliferation, invasion, tumor growth, and lung metastasis of ESCC cells. Both ectopic expression and induction of CXCL14 with 5-Aza-dC inhibited the activity of SRC, MEK1/2 and STAT3 in ESCC cells, while activated EGFR. Importantly, a combination of CXCL14 expression and SRC or EGFR inhibitor dramatically repressed the proliferation of ESCC cells and the growth of xenografts. Our findings revealed a direct tumor suppressor role of CXCL14, but not through the immune system. The data suggest that for ESCC patients with low level CXCL14, increasing CXCL14 expression combined with inhibition of SRC or EGFR might be a promising therapeutic strategy.

NEFL promotes invasion and migration of esophageal squamous carcinoma cells via the EGFR/AKT/S6 pathway.

To explore the expression, the roles and the underlying mechanism of neurofilament light chain (NEFL) in esophageal squamous cell carcinoma (ESCC), we firstly analyzed the NEFL mRNA and protein expression in ESCC and paired normal tissues by using Gene Expression Omnibus (GEO) database, and real-time quantitative reverse transcription PCR (qRT-PCR). The results showed that NEFL mRNA level was significantly upregulated in ESCC tissues compared with that of normal tissues. Western blot analysis revealed that NEFL protein level was also significantly upregulated in ESCC tissues. CCK8 and transwell assays were performed to analyze the effect of NEFL overexpression on the malignant phenotypes of ESCC cells, and the results showed that NEFL knockdown significantly impaired the ESCC cell invasion and migration in vitro. Xenograft assay in nude mice indicated that NEFL silencing suppressed tumor growth in vivo. At the molecular level, NEFL knockdown significantly upregulated E-cadherin and downregulated N-cadherin expression, suggesting that NEFL overexpression might influence the epithelial-mesenchymal transition (EMT) process. Furthermore, we found that NEFL knockdown significantly reduced the mRNA and protein expression of epidermal growth factor receptor (EGFR) and the phosphorylation levels of protein kinase B (PKB; also known as AKT) and ribosomal protein S6 (S6). Ectopic expression of EGFR after NEFL knockdown significantly restored the phosphorylation levels of AKT and S6 as well as the invasion and migration of ESCC cells. These data indicate that NEFL overexpression might promote the EMT process of ESCC cells via the EGFR/AKT/S6 pathway, ultimately enhancing the invasion and migration of ESCC cells.

FKBP10 promotes proliferation of glioma cells via activating AKT-CREB-PCNA axis.

BACKGROUND: Although the availability of therapeutic options including temozolomide, radiotherapy and some target agents following neurosurgery, the prognosis of glioma patients remains poor. Thus, there is an urgent need to explore possible targets for clinical treatment of this disease. METHODS: Tissue microarrays and immunohistochemistry were used to detect FKBP10, Hsp47, p-AKT (Ser473), p-CREB (Ser133) and PCNA expression in glioma tissues and xenografts. CCK-8 tests, colony formation assays and xenograft model were performed to test proliferation ability of FKBP10 in glioma cells in vitro and in vivo. Quantitative reverse transcriptase-PCR, western-blotting, GST-pull down, co-immunoprecipitation and confocal-immunofluorescence staining assay were used to explore the molecular mechanism underlying the functions of overexpressed FKBP10 in glioma cells. RESULTS: FKBP10 was highly expressed in glioma tissues and its expression was positively correlates with grade, poor prognosis. FKBP10-knockdown suppressed glioma cell proliferation in vitro and subcutaneous/orthotopic xenograft tumor growth in vivo. Silencing of FKBP10 reduced p-AKT (Ser473), p-CREB (Ser133), PCNA mRNA and PCNA protein expression in glioma cells. FKBP10 interacting with Hsp47 enhanced the proliferation ability of glioma cells via AKT-CREB-PCNA cascade. In addition, correlation between these molecules were also found in xenograft tumor and glioma tissues. CONCLUSIONS: We showed for the first time that FKBP10 is overexpressed in glioma and involved in proliferation of glioma cells by interacting with Hsp47 and activating AKT-CREB-PCNA signaling pathways. Our findings suggest that inhibition of FKBP10 related signaling might offer a potential therapeutic option for glioma patients.

Remarkable inhibition effects of afatinib alone or combining with paclitaxel in esophageal squamous cell carcinoma.

BACKGROUND AND AIM: Chemotherapy drugs do not work well in esophageal squamous cell carcinoma (ESCC), and none of the targeted drugs have been applied in clinic. This study aims to identify effective targeted drugs and related biomarkers for the treatment of ESCC. METHODS: The effect of 40 Food and Drug Administration-approved small-molecule inhibitors was first tested in five ESCC cell lines. CCK8 assays and xenografts derived from ESCC cell lines were performed to evaluate the anti-ESCC effects of inhibitors or chemotherapeutic agents in vitro and in vivo, respectively. Immunohistochemistry was utilized to analyze the p-EGFR expression in tissues. Western blot combining with gray analysis was conducted to detect the expression of interest protein. Flow cytometry and immunofluorescence assay were used to analyze apoptosis, cell cycle, and mitotic changes after drug treatment. RESULTS: Afatinib showed remarkable effects on inhibiting ESCC cells with higher expression of p-EGFR. Results from combinatorial screening in ESCC cells expressing lower phosphorylation level of EGFR showed that paclitaxel and afatinib presented a significant synergistic inhibitory effect (P < 0.001). Molecular analysis revealed that paclitaxel sensitized afatinib by activating EGFR, and afatinib in combination with paclitaxel effectively blocked MAPK pathway and induced G2/M cell arrest and apoptosis that is an indicator of mitotic catastrophe. CONCLUSIONS: Our data demonstrate that afatinib is an effective drug for patients with ESCC expressing higher phosphorylation level of EGFR. And for patients with lower p-EGFR in tumors, paclitaxel in combination with afatinib might be a promising therapeutic strategy in ESCC.

Elevated serum eotaxin and IP-10 levels as potential biomarkers for the detection of esophageal squamous cell carcinoma.

BACKGROUND AND AIMS: Esophageal squamous cell cancer (ESCC) is one of the leading malignant cancers with a high incidence and mortality. Exploring novel serum biomarkers will help improve the management and monitoring of ESCC. METHODS: In the present study, we first used a ProcartaPlex Array to screen for serum proteins that were increased in 40 ESCC patients compared with matched normal controls; we found that eight proteins (IL-2, IL-5, IP-10, IL-8, eotaxin, TNF-α, HGF, and MIP-1b) had higher serum levels in ESCC patients than in normal controls. We further verified the clinical relevance of the candidate biomarkers with a larger sample of sera. RESULTS: In the 174 tested ESCC patients and 189 normal controls, the serum levels of eotaxin and IP-10 were significantly higher in patients than in normal controls (p = 0.0038, 0.0031). In particular, these two proteins were also elevated in the sera of patients with early-stage (0-IIA) ESCC (p = 0.0041, 0.0412). When combining CEA and CYFRA21-1 (in use clinically) with eotaxin or IP-10, the effectiveness of detecting ESCC was superior to that of CEA and/or CYFRA21-1 alone. Moreover, the serum level of eotaxin dropped significantly after surgical resection of primary tumors compared with that in preoperative ESCC samples (p < 0.001). CONCLUSIONS: The data suggest that serum eotaxin and IP-10 might be potential biomarkers for the detection of ESCC.

PTP1B up-regulates EGFR expression by dephosphorylating MYH9 at Y1408 to promote cell migration and invasion in esophageal squamous cell carcinoma.

Esophageal squamous cell carcinoma (ESCC) is one of the most common cancers worldwide. Protein tyrosine phosphatase 1B (PTP1B) is a member of protein tyrosine phosphatases (PTPs) family. In our previous work, PTP1B was found to be overexpressed in ESCC tissues and made contributions to the the cell migration and invasion as well as lung metastasis of ESCC. In this study, we explored the underlying molecular mechanisms. PTP1B enhanced cell migration and invasion by promoting epidermal growth factor receptor (EGFR) expression in ESCC, which was relied on phosphatase activity of PTP1B. Using GST-pulldown combined with LC/MS/MS, we found that nonmuscle myosin IIA (MYH9) was a novel substrate of PTP1B in ESCC cells. PTP1B dephosphorylated MYH9 at Y1408, by which PTP1B up-regulated EGFR expression and enhanced cell migration and invasion in ESCC. In conclusion, our study first reported that PTP1B was the positive regulator of EGFR by dephosphorylating MYH9 at Y1408 to promote cell migration and invasion, which revealed the regulatory mechanism of PTP1B-MYH9-EGFR axis in ESCC.

PAI-1 overexpression promotes invasion and migration of esophageal squamous carcinoma cells.

Esophageal squamous cell carcinoma (ESCC) is one of the most common cancers worldwide. Plasminogen activator inhibitor-1 (PAI-1), encoded by SERPINE1, is highly expressed in various types of tumor tissues, which contributes to cancer progression. The present study explored the role and underlying mechanisms of PAI-1 in ESCC. We found that the PAI-1 protein was extracellularly secreted more from ESCC cells with high PAI-1 expression using Western blotting and enzyme linked immunosorbent assay (ELISA). Knockdown of SERPINE1 expression significantly inhibited the invasion and migration of ESCC KYSE150 and KYSE450 cell lines, which could be restored when adding exogenous human recombinant PAI-1 into the culture medium of the cells stably expressing SERPINE1 shRNA. In vivo experiments showed that SERPINE1 knockdown significantly inhibited xenograft growth and lung metastasis of ESCC cells. Molecular analysis demonstrated that PAI-1 activated AKT and ERK signaling pathways. Co-immunoprecipitation (Co-IP) assays identified that PAI-1 may interact with the membrane receptor LDL receptor related protein 1 (LRP1). These results indicated that overexpression of PAI-1, through interacting with LRP1, might enhance invasion and migration of ESCC cells as well as promote ESCC progression.

Identification of distinct mutational patterns and new driver genes in oesophageal squamous cell carcinomas and adenocarcinomas.

OBJECTIVES: Oesophageal squamous cell carcinoma (OSCC) and adenocarcinoma (OAC) are distinct cancers in terms of a number of clinical and epidemiological characteristics, complicating the design of clinical trials and biomarker developments. We analysed 1048 oesophageal tumour-germline pairs from both subtypes, to characterise their genomic features, and biological and clinical significance. DESIGN: Previously exome-sequenced samples were re-analysed to identify significantly mutated genes (SMGs) and mutational signatures. The biological functions of novel SMGs were investigated using cell line and xenograft models. We further performed whole-genome bisulfite sequencing and chromatin immunoprecipitation (ChIP)-seq to characterise epigenetic alterations. RESULTS: OSCC and OAC displayed nearly mutually exclusive sets of driver genes, indicating that they follow independent developmental paths. The combined sample size allowed the statistical identification of a number of novel subtype-specific SMGs, mutational signatures and prognostic biomarkers. Particularly, we identified a novel mutational signature similar to Catalogue Of Somatic Mutations In Cancer (COSMIC)signature 16, which has prognostic value in OSCC. Two newly discovered SMGs, CUL3 and ZFP36L2, were validated as important tumour-suppressors specific to the OSCC subtype. We further identified their additional loss-of-function mechanisms. CUL3 was homozygously deleted specifically in OSCC and other squamous cell cancers (SCCs). Notably, ZFP36L2 is associated with super-enhancer in healthy oesophageal mucosa; DNA hypermethylation in its super-enhancer reduced active histone markers in squamous cancer cells, suggesting an epigenetic inactivation of a super-enhancer-associated SCC suppressor. CONCLUSIONS: These data comprehensively contrast differences between OSCC and OAC at both genomic and epigenomic levels, and reveal novel molecular features for further delineating the pathophysiological mechanisms and treatment strategies for these cancers.

Overexpression of DNAJB6 promotes colorectal cancer cell invasion through an IQGAP1/ERK-dependent signaling pathway.

DNAJB6 is a member of the heat shock protein 40 (Hsp40) family. We here investigated the clinical correlation and biological role of DNAJB6 overexpression in colorectal cancer (CRC). The expression of DNAJB6 protein was examined in 200 cases of colorectal adenocarcinomas by immunohistochemistry (IHC) technology. Gene transfection and RNA interference were performed to determine the effect of DNAJB6 expression on the invasion of CRC cells and to explore the underlying molecular mechanisms in vitro and in vivo. Overexpression of DNAJB6 was found in 39% (78/200) of the CRC tissues, especially in tumors at pT4 as compared with at pT1-3 (P = 0.02). A Kaplan-Meier survival analysis revealed a correlation between DNAJB6 expression and overall survival (OS) times (P = 0.003). Multivariate analysis confirmed that DNAJB6 overexpression was an independent prognostic factor for CRC (P = 0.002). RNA interference-mediated silencing of the DNAJB6 gene inhibited the invasion of CRC cells in vitro were accompanied by a significant reduction in the protein levels of IQ-domain GTPase-activating protein 1 (IQGAP1) and phosphorylated ERK (pERK). An in vivo assay showed that inhibition of DNAJB6 expression decreased the lung metastases of CRC cells. IHC analysis of serial sections showed that there was a positive correlation between DNAJB6 and IQGAP1 expression in primary CRC tissues (P = 0.013). The data suggest that DNAJB6 plays an important oncogenic role in CRC cell invasion by up-regulating IQGAP1 and activating the ERK signaling pathway and that DNAJB6 may be used as a prognostic marker for CRC.

[IGHMBP2 overexpression promotes cell migration and invasion in esophageal squamous carcinoma].

Immunoglobulin mu binding protein 2 (IGHMBP2) is located in 11q13.2, which is frequently amplified in esophageal squamous cell carcinoma (ESCC). IGHMBP2 encodes a helicase involved in DNA replication and repair. IGHMBP2 protein also regulates gene transcription. The present study aims to explore the amplification of IGHMBP2 and its potential role in ESCC. A further analysis of our previously reported array-CGH data showed that IGHMBP2 was amplified in 28.9% of primary ESCC tumors. Fluorescence in situ hybridization (FISH) and Western blot showed that IGHMBP2 was amplified and overexpressed in KYSE30, KYSE180, KYSE510 and KYSE150 esophageal cancer cell lines. Transwell assays demonstrated that knockdown of IGHMBP2 in KYSE30 and KYSE150 inhibited cell invasion and migration, and increased the expression levels of E-cadherin. When rescue plasmids expressing IGHMBP2 were introduced, the abilities of cell invasion and migration were restored. These data suggest that IGHMBP2 overexpression may promote invasion and migration of ESCC cells through down-regulation of E-cadherin.

Inhibition of atypical protein kinase Cι induces apoptosis through autophagic degradation of ß-catenin in esophageal cancer cells.

Atypical protein kinase Cι (PKCι) has been identified as an oncoprotein in esophageal squamous cell carcinomas. However, the mechanisms underlying the role of PKCι in this disease remain unclear. In the present work, we found that inhibition of PKCι expression by RNAi induced apoptosis via the down-regulation of ß-catenin in esophageal cancer cells. Furthermore, we found that PKCι regulated ß-catenin in an autophagy dependent way. Since down-regulation of ß-catenin induced by knockdown of PKCι could be rescued by autophagy inhibition; knockdown of PKCι activated autophagy and promoted the recruitment of ß-catenin into autophagosome. These results suggested that PKCι positively regulated ß-catenin through negatively regulated autophagy and depletion of PKCι promoted apoptosis via autophagic degradation of ß-catenin in esophageal cancer cells. These data provide new insights into PKCι signaling in human cancer.

Bcl-2/IgH expression of diffuse large B-cell lymphoma cells in minimal bone marrow infiltration.

BACKGROUND: We sought to investigate the role of the Bcl-2 translocation at the chromosomal and protein levels in minimal bone marrow (BM) infiltration by diffuse large B-cell lymphomas (DLBCL). METHODS: The presence of the Bcl-2/IgH fusion gene was detected in BM samples and paraffin-embedded lymph node (LN) samples from 103 patients with DLBCLs using FISH. Bcl-2 protein levels in BM and paraffin-embedded tissues were quantified using immunocytochemistry (ICC) and immunohistochemistry (IHC), respectively. RESULTS: Bcl-2/IgH translocation in paraffin-embedded LN tissue sections was observed in 43 (41.7%) patients by FISH. Of the 43 patients, the Bcl-2/IgH rearrangement in the bone marrow specimens occurred in 34 patients. The Bcl-2/IgH recombination rate in stage III cancers was not significantly different compared to the rate observed in stage I/II cancers (p = 0.101), respectively showing no statistical differences between stage IV and I/II (p = 0.179). In 64.7% (22/34) of the cases with t(14;18), Bcl-2 was detected based on ICC analysis. Positive Bcl-2 ICC staining and the t(14;18) translocation were positively correlated (p < 0.001). We then applied our FISH method to slides with at least one abnormal cell and were subjected to FISH analysis after staining. During the follow-up, no infiltration by cytomorphology for 16 DLBCL patients whose bone marrow presented Bcl-2/IgH gene rearrangement at diagnosis, and two cases were positive by morphology compared to FISH-positive results 6 months later; 9 out of 16 patients (56.3%) presented with positive Bcl-2/IgH results earlier than the morphology evaluation after 12 months. CONCLUSIONS: Utilizing both FISH and cytologic morphology, the assessment of Bcl-2/IgH translocation status could contribute to the better detection of minimal bone marrow infiltration and relapse receiving treatment by DLBCL cells.

Tenascin-C as a potential biomarker and therapeutic target for esophageal squamous cell carcinoma.

PURPOSE: To establish a prognostic model of esophageal squamous cell carcinoma (ESCC) patients based on tenascin-C (TNC) expression level and clinicopathological characteristics, and to explore the therapeutic potential of TNC inhibition. METHODS: The expression of TNC was detected using immunohistochemistry (IHC) in 326 ESCC specimens and 50 normal esophageal tissues. Prognostic factors were determined by Cox regression analyses and were incorporated to establish the nomogram. The effects of TNC knockdown on ESCC cells were assessed in vitro and in vivo. Transcriptome sequencing (RNA-seq) and gene set enrichment analysis (GSEA) were performed to reveal signaling pathways regulated by TNC knockdown. The therapeutic significance of TNC knockdown combined with small-molecule inhibitors on cell proliferation was examined. RESULTS: TNC protein was highly expressed in 48.77 % of ESCC tissues compared to only 2 % in normal esophageal epithelia (p < 0.001). The established nomogram model, based on TNC expression, pT stage, and lymph node metastasis, showed good performance on prognosis evaluation. More importantly, the reduction of TNC expression inhibited tumor cell proliferation and xenograft growth, and mainly down-regulated signaling pathways involved in tumor growth, hypoxia signaling transduction, metabolism, infection, etc. Knockdown of TNC enhanced the inhibitory effect of inhibitors targeting ErbB, PI3K-Akt, Ras and MAPK signaling pathways. CONCLUSION: The established nomogram may be a promising model for survival prediction in ESCC. Reducing TNC expression enhanced the sensitivity of ESCC cells to inhibitors of Epidermal Growth Factor Receptor (EGFR) and downstream signaling pathways, providing a novel combination therapy strategy.

Reciprocal inhibition between TP63 and STAT1 regulates anti-tumor immune response through interferon-γ signaling in squamous cancer.

Squamous cell carcinomas (SCCs) are common and aggressive malignancies. Immune check point blockade (ICB) therapy using PD-1/PD-L1 antibodies has been approved in several types of advanced SCCs. However, low response rate and treatment resistance are common. Improving the efficacy of ICB therapy requires better understanding of the mechanism of immune evasion. Here, we identify that the SCC-master transcription factor TP63 suppresses interferon-γ (IFNγ) signaling. TP63 inhibition leads to increased CD8+ T cell infiltration and heighten tumor killing in in vivo syngeneic mouse model and ex vivo co-culture system, respectively. Moreover, expression of TP63 is negatively correlated with CD8+ T cell infiltration and activation in patients with SCC. Silencing of TP63 enhances the anti-tumor efficacy of PD-1 blockade by promoting CD8+ T cell infiltration and functionality. Mechanistically, TP63 and STAT1 mutually suppress each other to regulate the IFNγ signaling by co-occupying and co-regulating their own promoters and enhancers. Together, our findings elucidate a tumor-extrinsic function of TP63 in promoting immune evasion of SCC cells. Over-expression of TP63 may serve as a biomarker predicting the outcome of SCC patients treated with ICB therapy, and targeting TP63/STAT/IFNγ axis may enhance the efficacy of ICB therapy for this deadly cancer.

Autophagy negatively regulates cancer cell proliferation via selectively targeting VPRBP.

There have been multiple lines of evidence suggesting that autophagy selectively targets signalling proteins and regulates cancer cell signalling in addition to bulk clearance of long-lived proteins and organelles. Protein degradation through autophagy requires receptor protein LC3B to sequester the substrates into the autophagosome. In the present study, we screened LC3B (light-chain 3B)-binding partners and identified autophagic substrates in cancer cells. With lung cancer NCI-H1975 and oesophageal cancer KYSE30 cell lines as models, we found that VPRBP (viral protein R-binding protein) was a novel LC3B-binding protein through GST (glutathione transferase)-LC3B pull-down combined with LC-MS/MS (liquid chromatography-tandem MS) methods. Co-immunoprecipitation assay showed that VPRBP-LC3/p62 were in the same protein complex as the two cell lines. Induction of autophagy led to a down-regulation of VPRPB, which could be rescued by the inhibition of autophagy degradation by BFA1 (bafilomycin A1) and by the disruption of autophagy through ATG5-knockdown. We also found that induction of autophagy promotes VPRBP-LC3/p62 interaction. Immunohistochemical examination of human NSCLC (non-small cell lung cancer) tissues showed that VPRBP was positively correlated with p62 and negatively correlated with LC3B. Moreover, p62 and VPRBP were associated with poor prognosis in lung ADC (adenocarcinoma) (p62, P=0.019; VPRBP, P=0.005). Patients with low expression of both p62 and VPRBP showed the best prognosis.

Establishment of a human colorectal cancer cell line P6C with stem cell properties and resistance to chemotherapeutic drugs.

AIM: Cancer stem cells have the capacity to initiate and sustain tumor growth. In this study, we established a CD44(+) colorectal cancer stem cell line with particular emphasis on its self-renewal capacity, enhanced tumor initiation and drug resistance. METHODS: Fresh colon cancer and paired normal colon tissues were collected from 13 patients who had not received chemotherapy or radiotherapy prior to surgery. Among the 6 single-cell derived clones, only the P6C cell line was cultured for more than 20 passages in serial culture and formed holoclones with high efficiency, and then the stemness gene expression, colony formation, tumorigenicity and drug sensitivities of the P6C cell line were examined. RESULTS: Stemness proteins, including c-Myc, Oct3/4, Nanog, Lgr5, and SOX2, were highly expressed in the P6C cell line. Oct3/4-positive P6C cells mostly generated holoclones through symmetric division, while a small number of P6C cells generated meroclones through asymmetric division. P6C cells stably expressed CD44 and possessed a high capacity to form tumor spheres. A single cell-derived sphere was capable of generating xenograft tumors in nude mice. Compared to SW480 and HCT116 colorectal cancer cells, P6C cells were highly resistant to Camptothecin and 5-fluorouracil, the commonly used chemotherapeutic agents to treat colorectal cancers. CONCLUSION: We established a colorectal cancer stem cell line P6C with a high tumorigenic capacity and the characteristics of normal stem cells. It will benefit the mechanistic studies on cancer stem cells and the development of drugs that specifically target the cancer stem cells.

Elevated expression of the RNA-binding protein IGF2BP1 enhances the mRNA stability of INHBA to promote the invasion and migration of esophageal squamous cancer cells.

BACKGROUND: The mechanisms underlying the occurrence and development of esophageal squamous cell carcinoma (ESCC) remains to be elucidated. The present study aims to investigate the roles and implications of IGF2BP1 overexpression in ESCC. METHODS: IGF2BP1 protein expression in ESCC samples was assessed by immunohistochemistry (IHC), and the mRNA abundance of IGF2BP1 and INHBA was analyzed with TCGA datasets and by RNA in situ hybridization (RISH). The methylation level of the IGF2BP1 promoter region was detected by methylation-specific PCR (MSP-PCR). Cell viability, migration, invasion and in vivo metastasis assays were performed to explore the roles of IGF2BP1 overexpression in ESCC. RNA immunoprecipitation sequencing (RIP-seq) and mass spectrometry were applied to identify the target RNAs and interacting proteins of IGF2BP1, respectively. RIP-PCR, RNA pulldown, immunofluorescence (IF), gene-specific m6A PCR and RNA stability assays were used to uncover the molecular mechanisms underlying the malignant phenotypes of ESCC cells caused by IGF2BP1 dysregulation. BTYNB, a small molecular inhibitor of IGF2BP1, was evaluated for its inhibitory effect on the malignant phenotypes of ESCC cells. RESULTS: IGF2BP1 overexpression was detected in ESCC tissues and associated with the depth of tumor invasion. In addition, IGF2BP1 mRNA expression in ESCC cells was negatively correlated with the level of its promoter methylation. Knockdown of IGF2BP1 inhibited ESCC cell invasion and migration as well as tumor metastasis. Mechanistically, we observed that IGF2BP1 bound and stabilized INHBA mRNA and then resulted in higher protein expression of INHBA, leading to the activation of Smad2/3 signaling, thus promoting malignant phenotypes. The mRNA level of INHBA was upregulated in ESCC tissues as well. Furthermore, IGF2BP1 interacted with G3BP stress granule assembly factor 1 (G3BP1). Knockdown of G3BP1 also down-regulated the INHBA-Smad2/3 signaling. BTYNB abolished this activated signaling and significantly attenuated the malignant phenotypes of ESCC cells. CONCLUSIONS: Elevated expression of IGF2BP1 is a frequent event in ESCC tissues and might be a candidate biomarker for the disease. IGF2BP1 overexpression promotes the invasion and migration of ESCC cells by activating the INHBA-Smad2/3 pathway, providing a potential therapeutic target for ESCC patients with high expression of IGF2BP1.

Development of novel DNAJB6-KIAA1522-p-mTOR three-protein prognostic prediction models for CRC.

BACKGROUND: To evaluate the prognostic value of DNAJB6, KIAA1522, and p-mTOR expression for colorectal cancer (CRC) and to develop effective prognostic models for CRC patients. METHODS: The expression of DNAJB6, KIAA1522, and p-mTOR (Ser2448) was detected using immunohistochemistry in 329 CRC specimens. The prognostic values of the three proteins in the training cohort were assessed using Kaplan-Meier curves and univariate and multivariate Cox proportional hazards models. Prediction nomogram models integrating the three proteins and TNM stage were constructed. Subsequently, calibration curves, receiver operating characteristic (ROC) curves, the concordance index (C-index), and decision curve analysis (DCA) were used to evaluate the performance of the nomograms in the training and validation cohorts. RESULTS: The three proteins DNAJB6, KIAA1522, and p-mTOR were significantly overexpressed in CRC tissues (each P < 0.01), and their expression was an independent prognostic factor for overall survival (OS) and disease-free survival (DFS) (each P < 0.05). The area under the ROC curves (AUC) and C-index values were approximately 0.7. Additionally, the calibration curves showed that the predicted values and the actual values fit well. Furthermore, DCA curves indicated that the clinical value of the nomogram models was higher than that of TNM stage. Overall, the novel prediction models have good discriminability, sensitivity, specificity and clinical utility. CONCLUSION: The nomograms containing DNAJB6, KIAA1522, and p-mTOR may be promising models for predicting postoperative survival in CRC.

Characterization of genetic rearrangements in esophageal squamous carcinoma cell lines by a combination of M-FISH and array-CGH: further confirmation of some split genomic regions in primary tumors.

BACKGROUND: Chromosomal and genomic aberrations are common features of human cancers. However, chromosomal numerical and structural aberrations, breakpoints and disrupted genes have yet to be identified in esophageal squamous cell carcinoma (ESCC). METHODS: Using multiplex-fluorescence in situ hybridization (M-FISH) and oligo array-based comparative hybridization (array-CGH), we identified aberrations and breakpoints in six ESCC cell lines. Furthermore, we detected recurrent breakpoints in primary tumors by dual-color FISH. RESULTS: M-FISH and array-CGH results revealed complex numerical and structural aberrations. Frequent gains occurred at 3q26.33-qter, 5p14.1-p11, 7pter-p12.3, 8q24.13-q24.21, 9q31.1-qter, 11p13-p11, 11q11-q13.4, 17q23.3-qter, 18pter-p11, 19 and 20q13.32-qter. Losses were frequent at 18q21.1-qter. Breakpoints that clustered within 1 or 2 Mb were identified, including 9p21.3, 11q13.3-q13.4, 15q25.3 and 3q28. By dual-color FISH, we observed that several recurrent breakpoint regions in cell lines were also present in ESCC tumors. In particular, breakpoints clustered at 11q13.3-q13.4 were identified in 43.3% (58/134) of ESCC tumors. Both 11q13.3-q13.4 splitting and amplification were significantly correlated with lymph node metastasis (LNM) (P = 0.004 and 0.022) and advanced stages (P = 0.004 and 0.039). Multivariate logistic regression analysis revealed that only 11q13.3-q13.4 splitting was an independent predictor for LNM (P = 0.026). CONCLUSIONS: The combination of M-FISH and array-CGH helps produce more accurate karyotypes. Our data provide significant, detailed information for appropriate uses of these ESCC cell lines for cytogenetic and molecular biological studies. The aberrations and breakpoints detected in both the cell lines and primary tumors will contribute to identify affected genes involved in the development and progression of ESCC.