BACKGROUND: P16 inactivation is frequently accompanied by telomerase reverse transcriptase ( TERT ) amplification in human cancer genomes. P16 inactivation by DNA methylation often occurs automatically during immortalization of normal cells by TERT . However, direct evidence remains to be obtained to support the causal effect of epigenetic changes, such as P16 methylation, on cancer development. This study aimed to provide experimental evidence that P16 methylation directly drives cancer development. METHODS: A zinc finger protein-based P16 -specific DNA methyltransferase (P16-Dnmt) vector containing a "Tet-On" switch was used to induce extensive methylation of P16 CpG islands in normal human fibroblast CCD-18Co cells. Battery assays were used to evaluate cell immortalization and transformation throughout their lifespan. Cell subcloning and DNA barcoding were used to track the diversity of cell evolution. RESULTS: Leaking P16-Dnmt expression (without doxycycline-induction) could specifically inactivate P16 expression by DNA methylation. P16 methylation only promoted proliferation and prolonged lifespan but did not induce immortalization of CCD-18Co cells. Notably, cell immortalization, loss of contact inhibition, and anchorage-independent growth were always prevalent in P16-Dnmt&TERT cells, indicating cell transformation. In contrast, almost all TERT cells died in the replicative crisis. Only a few TERT cells recovered from the crisis, in which spontaneous P16 inactivation by DNA methylation occurred. Furthermore, the subclone formation capacity of P16-Dnmt&TERT cells was two-fold that of TERT cells. DNA barcoding analysis showed that the diversity of the P16-Dnmt&TERT cell population was much greater than that of the TERT cell population. CONCLUSION P16 methylation drives TERT -mediated immortalization and transformation of normal human cells that may contribute to cancer development.
Humans ; Telomerase/genetics* ; DNA Methylation/physiology* ; Fibroblasts/cytology* ; Cyclin-Dependent Kinase Inhibitor p16/metabolism* ; Cell Line ; Cell Transformation, Neoplastic/genetics*

Objective To investigate the effect of liquid-liquid phase separation(LLPS)of YTH domain family protein 2(YTHDF2)on the sodium arsenite-induced malignant transformation of skin cells,providing a new intervention target for the prevention and control of sodium arsenite-induced carcinogenesis.Methods The HaCaT cell model of malignant transformation was constructed by continuous treatment with 1 μmol/L sodium arsenite for 22 weeks,including cells with normal YTHDF2 LLPS(YTHDF2-wt)and cells with inhibited YTHDF2 LLPS(YTHDF2-mut).Confocal microscopy was employed to observe and characterize the LLPS droplets formed by YTHDF2 during sodium arsenite-induced malignant transformation of skin cells.Cell proliferation,scratch healing,and colony formation assays were performed to detect malignant phenotypes.Western blotting,quantitative reverse transcription PCR,and immunofluorescence experiments were conducted to examine the effects of YTHDF2 LLPS on the mRNA and protein levels of phosphatase and tensin homolog deleted on chromosome ten(PTEN)during sodium arsenite-induced malignant transformation of skin cells.Results After 4 weeks of sodium arsenite treatment,LLPS droplets of YTHDF2 appeared in YTHDF2-wt cells,and the number of droplets gradually increased as the treatment time was prolonged(F=35.252,P<0.001),while no phase-separated droplets were observed in YTHDF2-mut cells.Compared with YTHDF2-mut cells,YTHDF2-wt cells showed enhanced proliferation at the time points of 48 h(t=3.654,P=0.006)and 72 h(t=5.458,P<0.001)after 22 weeks of sodium arsenite treatment.The scratch healing rate of YTHDF2-wt cells was increased at the 8th(t=12.137,P<0.001)and 22th(t=4.484,P=0.011)weeks of sodium arsenite treatment.The number of colonies formed by YTHDF2-wt cells was higher at the 4th(t=3.365,P=0.027),8th(t=5.580,P=0.005),and 22th(t=3.328,P=0.029)weeks of sodium arsenite treatment.Compared with YTHDF2-mut cells,YTHDF2-wt cells showed down-regulated protein(t=-3.119,P=0.036)and mRNA(t=4.051,P=0.015) levels of PTEN after 22 weeks of sodium arsenite treatment.Immunofluorescence results showed that after 4 weeks of sodium arsenite treatment,YTHDF2 LLPS droplets in YTHDF2-wt cells were localized to stress granules,translation-related membrane-less organelles.Conclusions During sodium arsenite-induced malignant transformation of skin cells,YTHDF2 undergoes LLPS and localizes to stress granules,translation-related membrane-less organelles.YTHDF2 LLPS participates in sodium arsenite-induced malignant transformation of skin cells by down-regulating the mRNA level of the key tumor suppressor PTEN.
Arsenites/toxicity* ; Sodium Compounds/toxicity* ; Humans ; Cell Transformation, Neoplastic/drug effects* ; PTEN Phosphohydrolase/metabolism* ; Cell Proliferation ; Skin/cytology* ; RNA-Binding Proteins ; Skin Neoplasms/chemically induced* ; Cell Line

Integrins are a family of transmembrane receptors that connect the extracellular matrix and actin skeleton, which mediate cell adhesion, migration, signal transduction, and gene transcription. As a bi-directional signaling molecule, integrins can modulate many aspects of tumorigenesis, including tumor growth, invasion, angiogenesis, metastasis, and therapeutic resistance. Therefore, integrins have a great potential as antitumor therapeutic targets. In this review, we summarize the recent reports of integrins in human hepatocellular carcinoma (HCC), focusing on the abnormal expression, activation, and signaling of integrins in cancer cells as well as their roles in other cells in the tumor microenvironment. We also discuss the regulation and functions of integrins in hepatitis B virus-related HCC. Finally, we update the clinical and preclinical studies of integrin-related drugs in the treatment of HCC.
Humans ; Integrins/metabolism* ; Carcinoma, Hepatocellular/genetics* ; Liver Neoplasms/genetics* ; Cell Adhesion ; Carcinogenesis ; Cell Transformation, Neoplastic ; Tumor Microenvironment

Long non-coding RNA (lncRNA) is a hot topic in the field of researching tumor pathogenesis, and the importance in hematologic malignancies has been gradually being elucidated. LncRNA not only regulates hematological tumorigenesis and progression through affecting various biological processes such as cell proliferation, differentiation, pluripotency and apoptosis; moreover, abnormal expression and mutation of lncRNA are closely related to drug resistance and prognosis. Thus lncRNA can be used as novel biomarker and potential therapeutic target for hematological tumors. In this review, we will focus on the latest progress of lncRNA in hematological tumors to provide new ideas for the clinical diagnosis, prognostic evaluation together with research and development of target drugs for hematologic malignancies.
Humans ; RNA, Long Noncoding/metabolism* ; Hematologic Neoplasms/genetics* ; Neoplasms ; Carcinogenesis/pathology* ; Cell Transformation, Neoplastic/genetics* ; Gene Expression Regulation, Neoplastic

Cancer-associated fibroblasts (CAFs) and tumor-infiltrating immune cells are the most essential components of the tumor microenvironment (TME). They communicate with each other in tumor microenvironment and play a critical role in tumorigenesis and development. CAFs are very heterogeneous and different subtypes of CAFs display different functions. At the same time, it can contribute to the regulation of the function of tumor-infiltrating immune cells and eventually result in the carcinogenesis, tumor progression, invasion, metastasis and other biological behaviors of tumors by producting various growth factors and cytokines etc. Based on the current research results at home and abroad, this paper reviews the recent research progress on the regulation of CAFs on infiltrating immune cells in tumor microenvironment.
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Cancer-Associated Fibroblasts/metabolism* ; Carcinogenesis ; Cell Transformation, Neoplastic/metabolism* ; Humans ; Lung Neoplasms/metabolism* ; Tumor Microenvironment

YWHAE gene is located on chromosome 17p13.3, and its product 14-3-3epsilon protein belongs to 14-3-3 protein family. As a molecular scaffold, YWHAE participates in biological processes such as cell adhesion, cell cycle regulation, signal transduction and malignant transformation, and is closely related to many diseases. Overexpression of YWHAE in breast cancer can increase the ability of proliferation, migration and invasion of breast cancer cells. In gastric cancer, YWHAE acts as a negative regulator of MYC and CDC25B, which reduces their expression and inhibits the proliferation, migration, and invasion of gastric cancer cells, and enhances YWHAE-mediated transactivation of NF-κB through CagA. In colorectal cancer, YWHAE lncRNA, as a sponge molecule of miR-323a-3p and miR-532-5p, can compete for endogenous RNA through direct interaction with miR-323a-3p and miR-532-5p, thus up-regulating K-RAS/ERK/1/2 and PI3K-AKT signaling pathways and promoting the cell cycle progression of the colorectal cancer. YWHAE not only mediates tumorigenesis as a competitive endogenous RNA, but also affects gene expression through chromosome variation. For example, the FAM22B-YWHAE fusion gene caused by t(10; 17) (q22; p13) may be associated with the development of endometrial stromal sarcoma. At the same time, the fusion transcript of YWHAE and NUTM2B/E may also lead to the occurrence of endometrial stromal sarcoma. To understand the relationship between YWHAE, NUTM2A, and NUTM2B gene rearrangement/fusion and malignant tumor, YWHAE-FAM22 fusion gene/translocation and tumor, YWHAE gene polymorphism and mental illness, as well as the relationship between 17p13.3 region change and disease occurrence. It provides new idea and basis for understanding the effect of YWHAE gene molecular mechanism and genetic variation on the disease progression, and for the targeted for the diseases.
14-3-3 Proteins/metabolism* ; Breast Neoplasms/genetics* ; Cell Line, Tumor ; Cell Proliferation/genetics* ; Cell Transformation, Neoplastic/genetics* ; Colorectal Neoplasms/genetics* ; Endometrial Neoplasms ; Female ; Gene Expression Regulation, Neoplastic ; Humans ; MicroRNAs/genetics* ; Phosphatidylinositol 3-Kinases/metabolism* ; Sarcoma, Endometrial Stromal/pathology* ; Stomach Neoplasms/genetics* ; Transcription Factors/genetics* ; Translocation, Genetic

Tumor volume increases continuously in the advanced stage, and aside from the self-renewal of tumor cells, whether the oncogenic transformation of surrounding normal cells is involved in this process is currently unclear. Here, we show that oral squamous cell carcinoma (OSCC)-derived small extracellular vesicles (sEVs) promote the proliferation, migration, invasion, and epithelial-mesenchymal transition (EMT) of normal epithelial cells but delay their apoptosis. In addition, nuclear-cytoplasmic invaginations and multiple nucleoli are observed in sEV-treated normal cells, both of which are typical characteristics of premalignant lesions of OSCC. Mechanistically, miR-let-7c in OSCC-derived sEVs is transferred to normal epithelial cells, leading to the transcriptional inhibition of p53 and inactivation of the p53/PTEN pathway. In summary, we demonstrate that OSCC-derived sEVs promote the precancerous transformation of normal epithelial cells, in which the miR-let-7c/p53/PTEN pathway plays an important role. Our findings reveal that cancer cells can corrupt normal epithelial cells through sEVs, which provides new insight into the progression of OSCC.
Carcinoma, Squamous Cell/pathology* ; Cell Line, Tumor ; Cell Movement ; Cell Proliferation ; Cell Transformation, Neoplastic ; Down-Regulation ; Epithelial Cells/metabolism* ; Extracellular Vesicles/pathology* ; Humans ; MicroRNAs/metabolism* ; Mouth Neoplasms/pathology* ; PTEN Phosphohydrolase/metabolism* ; Tumor Suppressor Protein p53/metabolism*

Breast cancer is one of the most common malignancies that seriously threaten women's health. In the process of the malignant transformation of breast cancer, metabolic reprogramming and immune evasion represent the two main fascinating characteristics of cancer and facilitate cancer cell proliferation. Breast cancer cells generate energy through increased glucose metabolism. Lipid metabolism contributes to biological signal pathways and forms cell membranes except energy generation. Amino acids act as basic protein units and metabolic regulators in supporting cell growth. For tumor-associated immunity, poor immunogenicity and heightened immunosuppression cause breast cancer cells to evade the host's immune system. For the past few years, the complex mechanisms of metabolic reprogramming and immune evasion are deeply investigated, and the genes involved in these processes are used as clinical therapeutic targets for breast cancer. Here, we review the recent findings related to abnormal metabolism and immune characteristics, regulatory mechanisms, their links, and relevant therapeutic strategies.
Breast Neoplasms ; Cell Proliferation ; Cell Transformation, Neoplastic ; Energy Metabolism ; Female ; Humans ; Lipid Metabolism ; Signal Transduction

Interferon-γ (IFN-γ) has been used to control cancers in clinical treatment. However, an increasing number of reports have suggested that in some cases effectiveness declines after a long treatment period, the reason being unclear. We have reported previously that long-term IFN-γ treatment induces malignant transformation of healthy lactating bovine mammary epithelial cells (BMECs) in vitro. In this study, we investigated the mechanisms underlying the malignant proliferation of BMECs under IFN-γ treatment. The primary BMECs used in this study were stimulated by IFN-γ (10 ng/mL) for a long term to promote malignancy. We observed that IFN-γ could promote malignant cell proliferation, increase the expression of cyclin D1/cyclin-dependent kinase 4 (CDK4), decrease the expression of p21, and upregulate the expression of cellular-abelsongene (c-Abl) and histone deacetylase 2 (HDAC2). The HDAC2 inhibitor, valproate (VPA) and the c-Abl inhibitor, imatinib, lowered the expression level of cyclin D1/CDK4, and increased the expression level of p21, leading to an inhibitory effect on IFN-γ-induced malignant cell growth. When c-Abl was downregulated, the HDAC2 level was also decreased by promoted proteasome degradation. These data suggest that IFN-γ promotes the growth of malignant BMECs through the c-Abl/HDAC2 signaling pathway. Our findings suggest that long-term application of IFN-γ may be closely associated with the promotion of cell growth and even the carcinogenesis of breast cancer.
Animals ; Carcinogenesis/pathology* ; Cattle ; Cell Cycle Proteins/metabolism* ; Cell Proliferation/drug effects* ; Cell Transformation, Neoplastic/pathology* ; Cells, Cultured ; Epithelial Cells/pathology* ; Female ; Histone Deacetylase 2/metabolism* ; Imatinib Mesylate/pharmacology* ; Interferon-gamma/pharmacology* ; Mammary Glands, Animal/pathology* ; Mammary Neoplasms, Experimental/pathology* ; Proto-Oncogene Proteins c-abl/metabolism* ; Signal Transduction ; Valproic Acid/pharmacology*

BackgroundThe hedgehog signaling system (HHS) plays an important role in the regulation of cell proliferation and differentiation during the embryonic phases. However, little is known about the involvement of HHS in the malignant transformation of cells. This study aimed to detect the role of HHS in the malignant transformation of human bronchial epithelial (16HBE) cells.

MethodsIn this study, two microfluidic chips were designed to investigate cigarette smoke extract (CSE)-induced malignant transformation of cells. Chip A contained a concentration gradient generator, while chip B had four cell chambers with a central channel. The 16HBE cells cultured in chip A were used to determine the optimal concentration of CSE for inducing malignant transformation. The 16HBE cells in chip B were cultured with 12.25% CSE (Group A), 12.25% CSE + 5 μmol/L cyclopamine (Group B), or normal complete medium as control for 8 months (Group C), to establish the in vitro lung inflammatory-cancer transformation model. The transformed cells were inoculated into 20 nude mice as cells alone (Group 1) or cells with cyclopamine (Group 2) for tumorigenesis testing. Expression of HHS proteins was detected by Western blot. Data were expressed as mean ± standard deviation. The t-test was used for paired samples, and the difference among groups was analyzed using a one-way analysis of variance.

ResultsThe optimal concentration of CSE was 12.25%. Expression of HHS proteins increased during the process of malignant transformation (Group B vs. Group A, F = 7.65, P < 0.05). After CSE exposure for 8 months, there were significant changes in cellular morphology, which allowed the transformed cells to grow into tumors in 40 days after being inoculated into nude mice. Cyclopamine could effectively depress the expression of HHS proteins (Group C vs. Group B, F = 6.47, P < 0.05) and prevent tumor growth in nude mice (Group 2 vs. Group 1, t = 31.59, P < 0.01).

ConclusionsThe activity of HHS is upregulated during the CSE-induced malignant transformation of 16HBE cells. Cyclopamine can effectively depress expression of HHS proteins in vitro and prevent tumor growth of the transformed cells in vivo.

Animals ; Cell Transformation, Neoplastic ; genetics ; metabolism ; Gene Expression Regulation, Neoplastic ; genetics ; physiology ; Hedgehog Proteins ; genetics ; metabolism ; Lab-On-A-Chip Devices ; Mice ; Mice, Inbred BALB C ; Mice, Nude ; Microfluidics ; Signal Transduction ; genetics ; physiology ; Smoke ; Smoking ; adverse effects