Spred-3 mutation and Ras/Raf/MAPK activation confer acquired resistance to EGFR tyrosine kinase inhibitor in an EGFR mutated NSCLC cell line.

BACKGROUND: Epidermal growth factor receptor-tyrosine kinase inhibitors (EGFR-TKIs) are standard treatment for advanced non-small cell lung cancer (NSCLC). However, the emergence of EGFR-TKIs resistance poses a big challenge to the treatment. Although several resistant mutations have been identified, our understanding of the mechanisms underlying acquired EGFR-TKIs resistance remains incomplete. This study aimed to identify novel mutations and mechanisms that could contribute to acquired EGFR-TKIs resistance in EGFR mutated NSCLC cells. METHODS: Erlotinib resistant cells (HCC827/ER cells) were generated from the EGFR mutated NSCLC cell line HCC827, and whole-exome sequencing was performed to identify gene mutations in HCC827/ER cells. The Spred-3 expression was determined using quantitative real-time PCR (qPCR) and Western blotting assays, and the p-p44/42, p44/42, p-Akt and Akt expression was determined using Western blotting. The half maximal inhibitory concentration (IC50 value) was measured using the MTS assay, and cell migration was detected with a Transwell migration assay. RESULTS: Whole-exome sequencing identified deletion mutation c.120delG at exon 1 of the Spred-3 gene, resulting in a p.E40fs change in amino acid, in HCC827/ER cells. The Spred-3 expression was much reduced in HCC827/ER cells as compared to the HCC827 cells at both mRNA and protein levels. Knocking out Spred-3 in HCC827 cells using CRISPR/Cas9 increased erlotinib resistance and cell migration, while overexpressing Spred-3 in HCC827/ER cells using a cDNA construct reduced erlotinib resistance and cell migration. We also showed the Ras/Raf/MAPK pathway was activated in HCC827/ER cells, and inhibiting ERK1/2 in HCC827/Spred-3-sgRNA cells resulted in reduced erlotinib resistance and cell migration. CONCLUSIONS: The results of this study indicate that a loss-of-function mutation in Spred-3 resulted in activation of the Ras/Raf/MAPK pathway that confers resistance to EGFR-TKIs in NSCLC cells harboring an EGFR mutation.

lncRNA HOTAIR promotes gastric cancer proliferation and metastasis via targeting miR-126 to active CXCR4 and RhoA signaling pathway.

HOTAIR, a well-known long noncoding RNAs (lncRNA), has been recognized to contribute to the tumor metastasis in several tumors. But its role in gastric cancer remains elusive. Here, we reported an increase in HOTAIR promoted proliferation and metastasis of gastric cancer cell lines. The HOTAIR and miR-126 level was determined in 15 paired primary gastric cancer tissues and their adjacent noncancerous gastric tissues. Over-expression or downregulation HOTAIR was conducted in AGS or BGC-823 cells to investigate the impact of HOTAIR in proliferation and metastasis. Then dual luciferase reporter assay was utilized to study the interaction between CXCR4 and miR-126. Cells transfected with shHOTAIR or miR-126 mimic were subjected to western blot to investigate the role of SDF-1/CXCR4 signaling in HOTAIR mediated proliferation and metastasis. HOTAIR was highly expressed in gastric cancer tissues and several gastric cancer cell lines. Overexpressed HOTAIR facilitated proliferation and metastasis in vitro while HOTAIR knockdown inhibit proliferation and metastasis. A negative correlation was observed between miR-126 and HOTAIR. And, we also confirmed the decrease in miR-126 in clinic specimen. Furthermore, HOTAIR and miR-126 negatively regulated each other and then increase or decrease CXCR4 expression and downstream pathway, respectively. CXCR4 was confirmed as a direct target of miR-126. Our study demonstrated that high HOTAIR expression promote proliferation and metastasis in gastric cancer via miR-126/CXCR4 axis and downstream signaling pathways.

MiR-141-3p suppresses gastric cancer induced transition of normal fibroblast and BMSC to cancer-associated fibroblasts via targeting STAT4.

BACKGROUND: Cancer associated fibroblasts (CAFs) are known to be crucial constituents of cancer microenvironment (CME) and play an important role in initiation, progression and metastasis of various types of cancer, such as oral cancer, pancreatic cancer, and gastric cancer. CAFs are usually derived from normal fibroblasts (NFs), but the mechanism of the transition in gastric cancer has not yet been fully elucidated. METHODS: qRT-PCR and western blot were employed to investigate differences of miR-141 and STAT4 expression respectively. The CAF-like features and wnt/ß-catenin pathway related proteins in NF or BMSC were assessed by qRT-PCR or western blot after treated with the conditioned medium from different indicated groups of gastric cancer cells. The invasion and migration ability of AGS cells after transfection were analyzed by Transwell assay and wound healing assay. Dual-luciferase report assay was employed to determine the direct binding of miR-141 to STAT4 3' UTR. RESULTS: For the first time, the present study found that STAT4 over-expression in gastric cancer cells induced NFs to obtain CAF-like features via activating wnt/ß-catenin pathway. Further gain-of-function and loss-of-function analysis revealed that miR-141 not only limited the migration and invasion of the gastric cancer cells, but also inhibited the transition of NFs and BMSC to CAFs. The luciferase assay indicated that miR-141 directly targeted the 3'-UTR predictive sequence of STAT4. CONCLUSION: Our data showed that miR-141 inhibited migration and invasion of gastric cancer cells and inhibited transition from NFs to CAFs via targeting STAT4/wnt/ß-catenin pathway.

Effect of PD-1 knockout by CRISPR/Cas9 system on proliferation and IFN-γ secretion in human T lymphocytes / 中国肿瘤生物治疗杂志

@#Objective: : To explore the effect of PD-1 gene knockout by CRISPR/Cas9 system on the proliferation and IFN-γ secretion in human T cells. Methods: : The sequence of sgRNA targeting PD-1 was designed. The PD-1-sgRNA and Cas9 mRNA were synthesized by T7 RNApolymerase in vitro, and then the mixture of PD-1-sgRNAand Cas9 mRNAwas delivered into activated T cells by nucleofection. The efficiency of gene knockout was confirmed by sequencing. The phenotypes of T lymphocytes and the expression of PD-1 after gene knockout were analyzed by Flow cytometry. The proliferation of T lymphocytes was calculated by trypan blue counting. The level of IFN-γ secreted by T lymphocytes was detected by ELISA. Results： ：PD-1-sgRNA and Cas9 mRNA were successfully synthesized in vitro and delivered into T cells by nucleofection. Sequencing technology confirmed that the PD-1 gene sequence was edited and the editing efficiency was 58.3%. The expression of PD-1 on T lymphocyte surface was down-regulated successfully by CRISPR/Cas9 system [(9.6±1.85)% vs (16.2±2.05)%, P<0.05]. The knockout of PD-1 gene did not affect the proliferation and phenotype of T lymphocytes(P<0.05); However, compared with the control group, the level of IFN-γ secreted by T lymphocytes in the PD-1sgRNA group was significantly increased (P<0.01). Conclusion: : CRISPR/Cas9 system can successfully ablate PD-1 gene in human T lymphocytes, which could block the negative regulation of PD-1／PD-L1 and further promote the IFN-γ secretion in T cells.

[Construction of γ-synuclein eukaryotic expression vector and its effect on invasion and metastasis of colon cancer cell line SW1116 in vitro].

OBJECTIVE: To construct γ-synuclein gene eukaryotic expression vector, and to study its effect on the invasion of colon cancer cell line SW1116 and the adhesion between SW1116 and human umbilical vein endothelial cells(HUVECs) in vitro. METHODS: Total RNA was extracted from colon cancer cell line HT29 and the cDNA of γ-synuclein was amplified using RT-PCR. The digested fragment of cDNA coding sequence was linked to the eukaryotic expression vector pEGFP-C1 containing the GFP gene. After identification by sequence analysis, the recombinant plasmid was transfected into colon cancer cell line SW1116 via lipofectamine. The stable cell line was selected with G-418. The invasion in vitro was tested by Transwell invasion chamber assay. HUVECs were previously seeded onto 96-well plates before SW1116 cells seeded, and fluorescence intensity of GFP was detected to represent the amount of adhesion cells by ELISA. RESULTS: Human γ-synuclein eukaryotic expression vector was successfully constructed, which was stably expressed in SW1116 cells and could translate the GFP-γ-synuclein protein in vitro. γ-synuclein facilitated SW1116 cell passing through matrigel and filter membrane(198.4±20.7 vs. 98.8±13.2, P<0.05) and elevated the adherence of SW1116 cells to HUVECs(3.08±0.36 vs. 1.22±0.21, P<0.05). CONCLUSION: Expression of γ-synuclein can strengthen colon cancer cell SW1116 potentiality of invasion and metastasis in vitro.

[Effect of PC cell-derived growth factor RNA interference on biological behavior of esophageal squamous carcinoma cells].

OBJECTIVE: To investigate the effect of PC cell-derived growth factor (PCDGF) RNA interference on esophageal squamous carcinoma cells Eca-109 in vitro. METHODS: The PCDGF-shRNA expression vector was transfected into the Eca-109 cells by liposome. After transfection, the mRNA and protein expressions of PCDGF were detected by RT-PCR and Western-blot respectively. Cell Counting Kit-8 (CCK-8) assay and Boyden chamber method were performed to measure the cell proliferation and invasion ability respectively. RESULTS: The expression levels of PCDGF mRNA and protein were both decreased in Eca-109 cells transfected with PCDGF-shRNA expression vector (transfection group). Twenty-four, 48 and 72 h after transfection, the cells proliferation in the transfection group was inhibited, and the inhibition rate was 20.4%, 21.1% and 20.9% respectively. The cell proliferation activity in the transfection group was significantly lower than that in the non-transfection group, liposome group and negative vector group (all P<0.05). The number of cell migration in the non-transfection group,negative vector group, liposome group and transfection group was 118.8±12.0, 100.8±9.0, 114.3±4.7, and 53.5±16.3 respectively. The differences were statistically significant between the transfection group and the other 3 groups (all P<0.05). CONCLUSIONS: PCDGF RNA interference can inhibit the proliferation and invasion abilities of esophageal squamous carcinoma cells in vitro. PCDGF gene may be the new target of gene therapy.

Effects of γ-synuclein on the tumorigenicity and metastasis of colon cancer SW1116 cells in vitro and in vivo.

Recent evidence suggests the involvement of γ-synuclein in tumorigenesis and tumor progression. The present study was designed to further clarify the effects of γ-synuclein on the biological features of colon cancer cells in vitro and in vivo. We constructed the eukaryotic expression vector and siRNA vector and selected stable transfectants to respectively upregulate and downregulate γ-synuclein expression in SW1116 cells. we found that silencing of γ-synuclein significantly attenuated SW1116 cell growth and colony formation in vitro (P<0.05), and overexpression of γ-synuclein moderately enhanced cell growth and colony formation, but not significantly when compared with the parental SW1116 cells and empty vector-transfected cells (P>0.05). Meanwhile, overexpression of γ-synuclein significantly facilitated SW1116 cell migration, invasion and adhesion to human liver sinusoidal endothelial cells (HLSECs) in vitro (P<0.05), and the effects were less attenuated by γ-synuclein knockdown (P>0.05). Furthermore, γ-synuclein promoted these malignant phenotypes in a γ-synuclein expression quantity-dependent manner not only in vitro but also in the in vivo expression. stable cells were injected subcutaneously into the right flank, and injected intrasplenically in nude mice. γ-synuclein knockdown suppressed the tumorigenicity of SW1116 cells in mice, which presented significantly smaller tumor masses on day 6 over a 30-day period, compared with empty vector cells (P<0.05). Meanwhile, overexpression of γ-synuclein led to a profound augmentation of liver metastasis in nude mice, not only in macroscopic appearance but also in the size and weight of livers (P<0.05). These results provide strong evidence that suggests γ-synuclein plays a positive role in the progression of colorectal cancer.

Floating cells with stem cell properties in gastric cell line SGC-7901.

AIMS: To obtain floating spheres from the adherent gastric cancer cell line SGC-7901 and to analyze the properties of the spheres. METHODS: Serum-free medium was applied to cultured SGC-7901 cells. Limiting dilution assay, tumor formation assay, microarray analysis, and real-time fluorescent quantitative PCR were used to test the stem cell properties of the spheres. RESULTS: A subpopulation of SGC-7901 cells formed floating spheres in serum-free medium. These cells showed enhanced tumorigenic ability and also highly expressed certain stem-cell-associated proteins. CONCLUSIONS: We successfully propagated floating spheres with stem cell properties in the SGC-7901 gastric cell line.

Treatment of established colon carcinoma-bearing mice by dendritic cells pulsed with lysates of heat-treated tumor cells.

To investigate the therapeutic effect of dendritic cells pulsed with lysates of heat-treated CT26 colon carcinoma cells. Bone marrow-derived DCs were pulsed with lysates of heat-treated tumor cells and were used to immunize BALB/c mice with established colon carcinoma. Cytotoxic T lymphocyte (CTL) response was detected. The therapeutic effect induced by DCs was observed by tumor weight and survival time. DCs pulsed with lysates of heat-treated tumor cells markedly induced specific cytotoxic activity of CTLs. Tumor growth in the immunized BALB/c mice was significantly inhibited and the survival time of the tumor-bearing mice was prolonged. DCs pulsed with lysates of heat-treated tumor cells have an observable therapeutic effect on established colon carcinoma-bearing mice.