E-cadherin knockdown increases β-catenin reducing colorectal cancer chemosensitivity only in three-dimensional cultures

Wnt Signaling and Cadherin Expressions in Different Staging of Colorectal Cancer as Biomarkers for Metastasis: Study of SW480, COLO 320DM, and HCT116 Cellines

BACKGROUND: Early metastases is still unresolved problem in cancer management, eventually in colorectal cancer (CRC). In addition, many markers are useful just only in the late stage of CRC. AIM: This study evaluates the differences in the expression intensity of nuclear β-catenin, cytoplasmic β-catenin, E-cadherin, and N-cadherin between CRC SW480 cell line as control group and COLO320DM and HCT116 cell lines as case groups. MATERIALS AND METHODS: This study applied experimental research design with the different test methods. Culture growing and subcultures manufacturing for the CRC cell line models were done initially and followed by the immunofluorescence method by administering antibodies on β-catenin, E-cadherin, and N-cadherin, and continued with staining process using fluorescein-5-isothiocyanate and 4’, 6-diamidino-2-phenylindole. Observations were done using an immunofluorescence microscope. Calculation of area density in each cell to perceive the expressions of cytoplasmic and nuclear β-catenin, E-cadherin, and N-cadherin was conducted using ImageJ software, resulted in mean fluorescence intensity. RESULTS: There are significant differences in the expressions of cytoplasmic β-catenin, nuclear β-catenin, E-cadherin, and N-cadherin among SW480, COLO320DM, and HCT116 cell lines (p < 0.05). Despite no significant differences in cytoplasmic and nuclear β-catenin expressions between SW480 and HCT116 cell lines, and in E-cadherin and N-cadherin expressions between COLO320DM and HCT116 cell lines (p > 0.05). SW480 cell line has a higher expression of nuclear β-catenin than the cytoplasm (p < 0.05). CONCLUSION: This study reveals differences in the expression of nucleic and cytoplasmic β-catenin, E-cadherin, and N-cadherin in three stages of CRC (Duke B, C, and D) refer to different activation invasion, migration, and metastatic processes. Furthermore, the high expression of nuclear β-catenin and N-cadherin in the early stage of CRC indicate there is a metastatic process in that stage, so nuclear β-catenin and cadherin can be considered as potential biomarkers in the early stage of this cancer.

SENP1 participates in Irinotecan resistance in human colon cancer cells

Colorectal cancer is one of the most prevalent cancers in the world. Chemoresistance has always been a problem encountered in its treatment. It is known that SUMOylation may regulate protein stability and decomposition, and even affect the protein translocation and posttranslational modification in cells. Sentrin-specific protease 1 (SENP1) is involved in the maturation of SUMO protein, and on the other hand, plays a role in deSUMOylation, which dissociates the target protein from SUMO and prevents further degradation of the target protein. In this study, we established an Irinotecan (CPT-11) resistant human colon cancer LoVo strain (LoVo^R-CPT-11 ) to investigate the role of SENP1 in the development of drug resistance in colorectal cancer. The abundant accumulation of SENP1 and HIF-1α proteins and the increase of SUMO pathway enzymes were observed in LoVo^R-CPT-11 cells while the protein markers of proliferation, angiogenesis, and glycolysis were upregulated. Knockdown of SENP1 reduced the migration ability and trigged re-sensitivity of LoVo^R-CPT-11 cells to CPT-11 treatment. The analysis of SENP1 and HIF-1α gene expressions from TCGA/GTEx datasets using the GEPIA web server showed a positive correlation between SENP1 and HIF-1α in colorectal cancer patients and the high expression of these two genes might predict a poor outcome clinically. In conclusion, SENP1 might play an important role in CPT-11 resistance in colorectal cancer. Targeting SENP1 to reduce the resistant property could be considered in prospective clinical studies.

A novel focal adhesion related gene signature for prognostic prediction in hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is a highly heterogeneous disease. Reduced expression of focal adhesion is considered as an important prerequisite for tumor cell invasion and metastasis. However, the prognostic value of focal adhesion related genes in HCC remains to be further determined. In this study, RNA expression profiles were downloaded from public databases. A five focal adhesion related gene signature model was established by the least absolute shrinkage and selection operator Cox regression analysis, which categorized patients into high- and low-risk groups. Multivariate Cox regression analysis showed that the risk score was an independent predictor for overall survival. Single-sample gene set enrichment analysis revealed that immune status was different between the two risk groups, and tumor-related pathways were enriched in high-risk group. The risk score was significantly associated with tumor grade, tumor stage, immune scores, and immune infiltrate types. Pearson correlation showed that the expression level of prognostic genes was associated with anti-tumor drug sensitivity. Besides, the mRNA and protein expression of prognostic genes was significantly different between HCC tissues and adjacent non-tumorous tissues in our separate cohort. Taken together, a novel focal adhesion related gene signature can be used for prognostic prediction in HCC, which may be a therapeutic alternative.

OIP5-AS1 contributes to tumorigenesis in hepatocellular carcinoma by miR-300/YY1-activated WNT pathway

Background

It has reported that long non-coding RNAs (lncRNAs) exerted regulatory functions by targeting specific genes through a competing endogenous RNA (ceRNA) pathway. LncRNA OIP5-AS1 has been identified as a tumor-enhancer in several tumor types. Nonetheless, its molecular mechanism in HCC remains to be masked.

Aim of the study

This study was aimed at exploring whether and how OIP5-AS1 exert functions in HCC.

Methods

qRT-PCR and western blot were employed for detecting gene expression. CCK-8, colony formation and EdU assays were implemented to evaluate the proliferative ability of HCC cells. Caspase-3 activity and flow cytometry analyses were implemented to determine cell apoptosis and cell cycle distribution. RNA pull down, ChIP, RIP and luciferase reporter assays explored the interplays between molecules.

Results

YY1 was upregulated in HCC cells, and silenced YY1 restrained HCC cell proliferation in vitro and hampered tumor growth in vivo. Later, we discovered that miR-300 could regulate WNT pathway via targeting YY1. Furthermore, OIP5-AS1 was identified as the sponge of miR-300 and promoted cell growth in HCC. Importantly, YY1 transcriptionally activate OIP5-AS1 in turn. Rescue experiments indicated that miR-300 inhibition or YY1 overexpression abrogated the inhibitive effect of OIP5-AS1 silencing on the malignant growth of HCC cells.

Conclusions

OIP5-AS1/miR-300/YY1 feedback loop facilitates cell growth in HCC by activating WNT pathway.

β-catenin promotes MTX resistance of leukemia cells by down-regulating FPGS expression via NF-κB

Background

Aberrant activation of β-catenin has been shown to play important roles in the chemoresistance of acute lymphoblastic leukemia (ALL), but the involvement and mechanism of β-catenin in methotrexate (MTX) resistance is poorly understood. In the present study, we demonstrate a critical role of β-catenin-NF-κB-FPGS pathway in MTX resistance in the human T-lineage ALL cell lines.

Methods

Lentivirus sh-β-catenin was used to silence the expression of β-catenin. Flow cytometry was performed to detect apoptosis after MTX treatment. Western blot, real-time PCR, Co-immunoprecipitation (Co-IP), Chromatin immunoprecipitation (ChIP), Re-ChIP, and Luciferase assay were utilized to investigate the relationship among β-catenin, nuclear factor (NF)-κB, and folypoly-γ-glutamate synthetase (FPGS).

Results

Depletion of β-catenin significantly increased the cytotoxicity of MTX. At the molecular level, knockdown of β-catenin caused the increase of the protein level of FPGS and NF-κB p65. Furthermore, β-catenin complexed with NF-κB p65 and directly bound to the FPGS promoter to regulate its expression. In addition, β-catenin repression prolonged the protein turnover of FPGS.

Conclusions

Taken together, our results demonstrate that β-catenin may contribute to MTX resistance in leukemia cells via the β-catenin-NF-κB-FPGS pathway, posing β-catenin as a potential target for combination treatments during ALL therapy.

ADAM10 promotes cell growth, migration, and invasion in osteosarcoma via regulating E-cadherin/β-catenin signaling pathway and is regulated by miR-122-5p

Background

Osteosarcoma is a malignant bone tumor. Increasing evidences have revealed that a disintegrin and metalloproteinase 10 (ADAM10) is implicated in tumor development. The main purpose of this study is to explore the effects of ADAM10 on osteosarcoma cell functions and the underlying molecular mechanisms.

Methods

Western blot and quantitative real-time PCR were performed to detect the expression of ADAM10 in one osteoblast (hFOB 1.19) and six osteosarcoma cells (Saos-2, SW1353, HOS, U-2OS, MG63, and 143B). The biological functions of ADAM10 in osteosarcoma cells were measured by cell counting kit-8 assay, flow cytometry, wound healing assay, and transwell assay. The interaction between miR-122-5p and ADAM10 was validated using dual-luciferase reporter assay. The effect of ADAM10 on the tumorigenicity of osteosarcoma cells was evaluated in a nude mice model in vivo.

Results

We found that the expression of ADAM10 was relatively high in osteosarcoma cells compared with that in osteoblast. ADAM10 promoted osteosarcoma cell growth, migration, and invasion. Mechanism studies showed that knockdown of ADAM10 inactivated E-cadherin/β-catenin signaling pathway, as evidenced by increased the level of E-cadherin, reduced nuclear translocation of β-catenin, and decreased the levels of MMP-9, Cyclin D1, c-Myc, and Survivin. Downregulation of ADAM10 suppressed the tumorigenicity of osteosarcoma cells in vivo. Furthermore, ADAM10 was validated to be a downstream target of microRNA-122-5p (miR-122-5p). MiR-122-5p-induced inhibition of cell proliferation, migration, and invasion was reversed by overexpression of ADAM10 in osteosarcoma cells.

Conclusions

Collectively, the key findings of this study are that ADAM10 promotes osteosarcoma cell proliferation, migration, and invasion by regulating E-cadherin/β-catenin signaling pathway, and miR-122-5p can target ADAM10, indicating that miR-122-5p/ADAM10 axis might serve as a therapeutic target of osteosarcoma.

Inhibition of LOXL2 Enhances the Radiosensitivity of Castration-Resistant Prostate Cancer Cells Associated with the Reversal of the EMT Process

INTRODUCTION

Radiotherapy is the mainstay in the treatment of prostate cancer. However, significant radioresistance of castration-resistant prostate cancer (CRPC) cells constitutes a main obstacle in the treatment of this disease. By using bioinformatic data mining methods, LOXL2 was found to be upregulated in both androgen-independent prostate cancer cell lines and radioresistant tumor samples collected from patients with prostate cancer. We speculate that LOXL2 may play an important role in the radioresistance of CRPC cells.

METHODS

The effect of LOXL2 knockdown on the radiosensitivity of androgen-independent prostate cancer cells lines was measured by the clonogenic assay and xenograft tumor experiments under in vitro and in vivo conditions, respectively. In studies on the mechanism, we focused on the EMT phenotype changes and cell apoptosis changes induced by LOXL2 knockdown in DU145 cells. The protein levels of three EMT biomarkers, namely, E-cadherin, vimentin, and N-cadherin, were measured by western blotting and immunohistochemical staining. Cell apoptosis after irradiation was measured by flow cytometry and caspase-3 activity assay. Salvage experiment was also conducted to confirm the possible role of EMT in the radiosensitization effect of LOXL2 knockdown in CRPC cells.

RESULTS

LOXL2 knockdown in CRPC cells enhanced cellular radiosensitivity under both in vitro and in vivo conditions. A significant reversal of EMT was observed in LOXL2-silenced DU145 cells. Cell apoptosis after irradiation was significantly enhanced by LOXL2 knockdown in DU145 cells. Results from the salvage experiment confirmed the key role of EMT process reversal in the radiosensitization effect of LOXL2 knockdown in DU145 cells.

CONCLUSIONS

LOXL2 plays an important role in the development of cellular radioresistance in CRPC cells. Targeting LOXL2 may be a rational avenue to overcome radioresistance in CRPC cells. A LOXL2-targeting strategy for CRPC treatment warrants detailed investigation in the future.

USP20 positively regulates tumorigenesis and chemoresistance through β-catenin stabilization

β-catenin is a major transcriptional activator of the canonical Wnt/β-catenin signaling pathway. It is important for a series of biological processes including tissue homeostasis, and embryonic development and is involved in various human diseases. Elevated oncogenic activity of β-catenin is frequently observed in cancers, which contributes to survival, metastasis and chemo-resistance of cancer cells. However, the mechanism of β-catenin overexpression in cancers is not well defined. Here we demonstrate that the deubiquitination enzyme USP20 is a new regulator of the Wnt/β-catenin signaling pathway. Mechanistically, USP20 regulates the deubiquitination of β-catenin to control its stability, thereby inducing proliferation, invasion and migration of cancer cells. High expression of USP20 correlates with increased β-catenin protein level in multiple cancer cell lines and patient samples. Moreover, knockdown of USP20 increases β-catenin polyubiquitination, which enhances β-catenin turnover and cell sensitivity to chemotherapy. Collectively, our results establish the USP20-β-catenin axis as a critical regulatory mechanism of canonical Wnt/β-catenin signaling pathway with an important role in tumorigenesis and chemo response in human cancers.

Fusobacterium nucleatum promotes the progression of colorectal cancer by interacting with E-cadherin

Increasing evidence suggests that Fusobacterium nucleatum is involved in colorectal carcinogenesis. Previous studies have explored whether F. nucleatum may trigger colonic epithelial-mesenchymal transition. The results of the present study demonstrated that F. nucleatum enhances the proliferation and invasion of NCM460 cells compared with that of normal control and DH5α cells. Furthermore, F. nucleatum significantly increased the phosphorylation of p65 (a subunit of nuclear factor-κB), as well as the expression of interleukin (IL)-6, IL-1β and matrix metalloproteinase (MMP)-13. Additionally, F. nucleatum infection did not affect the expression levels of epithelial (E-)cadherin and β-catenin. E-cadherin knockdown in NCM460 cells did not induce the activation of inflammatory responses in response to F. nucleatum infection, whereas it increased inflammation in response to β-catenin silencing. F. nucleatum infection could not increase the proportion of cells at S phase when E-cadherin was silenced. Nevertheless, F. nucleatum infection enhanced the proportion of NCM460 cells at S phase when transfected with small interfering RNAs to knock down β-catenin expression. In conclusion, the results of the present study demonstrated that F. nucleatum infection interacted with E-cadherin instead of β-catenin, which in turn enhances the malignant phenotype of colorectal cancer cells.

MALDI Mass Spectrometry Imaging for Evaluation of Therapeutics in Colorectal Tumor Organoids

Patient-derived colorectal tumor organoids (CTOs) closely recapitulate the complex morphological, phenotypic, and genetic features observed in in vivo tumors. Therefore, evaluation of drug distribution and metabolism in this model system can provide valuable information to predict the clinical outcome of a therapeutic response in individual patients. In this report, we applied matrix-assisted laser desorption/ionization mass spectrometry imaging (MALDI-MSI) to examine the spatial distribution of the drug irinotecan and its metabolites in CTOs from two patients. Irinotecan is a prodrug and is often prescribed as part of therapeutic regimes for patients with advanced colorectal cancer. Irinotecan shows a time-dependent and concentration-dependent permeability and metabolism in the CTOs. More interestingly, the active metabolite SN-38 does not co-localize well with the parent drug irinotecan and the inactive metabolite SN-38G. The phenotypic effect of irinotecan metabolism was also confirmed by a viability study showing significantly reduced proliferation in the drug treated CTOs. MALDI-MSI can be used to investigate various pharmaceutical compounds in CTOs derived from different patients. By analyzing multiple CTOs from a patient, this method could be used to predict patient-specific drug responses and help to improve personalized dosing regimens. Graphical Abstract ᅟ.

Dexamethasone affects cell growth/apoptosis/chemosensitivity of colon cancer via glucocorticoid receptor α/NF-κB

Glucocorticoids are effective to treat lymphoma and leukemia. Their effect in colon cancer remains far from clear. Here, we found that glucocorticoid receptor (GR) α protein level was dramatically lower in colon cancer than in lymphoma. Colon cell lines LoVo and HCT116 were GRα-rich and GRα was not detectable in HT29 or SW480. Dexamethasone significantly inhibited cell growth of GRα-rich cell lines and did not significantly affect GRα-negative cell lines. Dexamethasone induced apoptosis and increased chemosensitivity of GRα-rich cell lines. Knockdown of GRα significantly attenuated dexamethasone effects on cell growth, apoptosis and chemosensitivity. NF-κB p65 significantly correlated with GRα in colon cancer samples. Dexamethasone decreased NF-κB p65 activity. Knockdown of NF-κB p65 increased apoptosis. Our data demonstrate GRα protein level is dramatically lower in colon cancer than in lymphoma. Dexamethasone inhibits cell growth, induces apoptosis and enhances chemosensitivity in colon cancer, at least partly, via GRα and NF-κB.

Chemoresistance of colorectal cancer to 5-fluorouracil is associated with silencing of the BNIP3 gene through aberrant methylation

Purpose To investigate the correlation between chemoresistance of colorectal cancer to 5-fluorouracil and BNIP3 and the underlying mechanism.

Methods BNIP3 protein in specimens was evaluated using immunohistochemistry. Semi-quantitative reverse transcription PCR and Western blot was employed to assay gene expression. The promoter methylation status of BNIP3 was examined by methylation-specific PCR. Drug sensitivity was assayed using MTT assay.

Results Specimens from 81 patients with colorectal cancer receiving 5-fluorouracil-based chemotherapy were analyzed. BNIP3 expression was negative in 42 cancer samples. The mean score of BNIP3 in cancer was 1.8±0.2 and it was 3.7±0.5 in adjacent colorectum (p<0.05). The response rate of the BNIP3 positive group was 63.6% and that of the negative group was 36.4% (p=0.021). The median PFS of the BNIP3 positive group was 9.25 months and that of the BNIP3 negative group was 6.5 months (p=0.011). BNIP3 mRNA was not detectable in 4 of 8 colorectal cell lines and all these 4 cell lines displayed BNIP3 methylated allele only. Other 4 cell lines what expressed detectable BNIP3 displayed BNIP3 unmethylated allele only or both unmethylated and methylated alleles. 5-Aza dramatically increased BNIP3 expression. Knockdown of DNMT1 increased BNIP3. Knockdown of DNMT3B alone did not detectably change BNIP3 expression while knockdown of both DNMT1 and DNMT3B increased BNIP3 expression more than knockdown of DNMT1 alone. Knockdown of BNIP3 decreased chemosensitivity to 5-fluorouracil and increasing BNIP3 through demethylation increased chemosensitivity.

Conclusion Chemoresistance of colorectal cancer to 5-fluorouracil is associated with silencing of the BNIP3 gene through aberrant methylation via DNMT1/DNMT3B.

P53 Is Involved in a Three-Dimensional Architecture-Mediated Decrease in Chemosensitivity in Colon Cancer

Three-dimensional (3D) culture models represent a better approximation of solid tumor tissue architecture, especially cell adhesion, in vivo than two-dimensional (2D) cultures do. Here, we explored the role of architecture in chemosensitivity to platinum in colon cancer. Under the 3D culture condition, colon cancer cells formed multicellular spheroids, consisting of layers of cells. 3D cultures displayed significantly decreased sensitivity to platinum compared with 2D cultures. Platinum increased p53 in a dose-dependent and time-dependent manner. There was no detectable difference in basal p53 levels between 3D cultures and 2D cultures but cisplatin induced less p53 in both HCT116 3D cultures and LoVo 3D cultures. It was not due to cisplatin concentration because cisplatin induced similar γ-H2AX in 3D vs 2D. Knockdown of p53 significantly decreased sensitivity to platinum in 3D cultures. Knockdown of p53 decreased cleaved caspase 3 and apoptosis induced by cisplatin. These findings indicate that 3D architecture confers decreased chemosensitivity to platinum and p53 is involved in the mechanism. Knockdown of p53 decreased cisplatin's induction of c-Jun N-terminal kinase 1/2 (JNK1/2) activation, whereas inhibition of JNK1/2 activation increased chemosensitivity. Inhibition of p38 activation decreased cisplatin's induction of p53, but no difference in p38 activation by cisplatin was observed between 2D cultures and 3D cultures. Taken together, our results suggest that p53 is involved in a 3D architecture-mediated decrease in chemosensitivity to platinum in colon cancer. Mitogen-activated protein kinases (JNK1/2 and p38) do not play a dominant role in the mechanism.