PIM1-catalyzed CBX8 phosphorylation promotes the oncogene-induced senescence of human diploid fibroblast.

The proto-oncogene PIM1 encodes Ser/Thr kinase and regulates cell growth, differentiation and apoptosis. However, more and more studies including ours have found that PIM1 can induce senescence in normal human diploid fibroblasts and behave as a tumor suppressor. But the relevant molecular mechanism of this process is not yet clear. It has been reported that Chromobox homolog 8 (CBX8) binds directly to INK4A as a transcriptional repressor, thereby suppressing stress-induced senescence. Here we report that PIM1 can phosphorylate CBX8 to promote its degradation, thereby up-regulating p16, during PIM1-induced cell senescence. Overexpression of CBX8 can inhibit PIM1-induced cell senescence. These data suggest that to promote CBX8 degradation may be an important molecular mechanism of PIM1-induced cell senescence.

P16 promotes the growth and mobility potential of breast cancer both in vitro and in vivo: the key role of the activation of IL-6/JAK2/STAT3 signaling.

P16 is the product of cyclin-dependent kinase 2 (CDKN2A) gene and plays multi-pronged roles in the cancer progression. Breast cancer (BC) is the most commonly diagnosed cancer type among females. In the current study, the potential function of P16 in the growth and metastasis of BC was investigated. Firstly, the expression statuses of P16 in different cancer types were investigated using Oncomine database and validated with corresponding cancer cell lines. Afterwards, the expression of P16 was knocked down in BC cell line BT-549 and the effect on the cell proliferation, sensitivity to paclitaxel (TAX), apoptosis, migration, and invasion abilities was assessed using CCK-8, Edu, flow cytometry, scratch, and transwell assays, respectively. The influence of P16 inhibition and P16 overexpression on the activity of IL-6/JAK/STAT3 signaling was explored. Additionally, the effect of P16 inhibition on the tumor growth was verified with a BC xenograft mice model. The abnormal expression of P16 was detected in BC cell line BT-549 as well as colorectal cancer and osteosarcoma cell lines. The inhibition of P16 suppressed the cell proliferation, invasion, and migration abilities while induced the apoptosis and sensitivity to TAX in BT-549 cells. At molecular level, P16 knockdown inhibited the expression of IL6ST and Survivin, and the phosphorylation of JAK2 and STAT3. However, the induced expression of P16 in P16-knockdown BT-549 cells restored the activity of IL-6/JAK2/STAT3 pathway. The results of in vitro assays were confirmed with BC xenograft models: the inhibition of P16 decreased the tumor growth rate. Findings outlined in the current study demonstrated that the inhibition of P16 decreased the growth and metastasis potential of BC cells by inhibiting IL-6/JAK2/STAT3 signaling.

Grating-based x-ray dark-field CT for lung cancer diagnosis in mice.

BACKGROUND: The low absorption of x-rays in lung tissue and the poor resolution of conventional computed tomography (CT) limits its use to detect lung disease. However, x-ray dark-field imaging can sense the scattered x-rays deflected by the structures being imaged. This technique can facilitate the detection of small alveolar lesions that would be difficult to detect with conventional CT. Therefore, it may provide an alternative imaging modality to diagnose lung disease at an early stage. METHODS: Eight mice were inoculated with lung cancers simultaneously. Each time two mice were scanned using a grating-based dark-field CT on days 4, 8, 12, and 16 after the introduction of the cancer cells. The detectability index was calculated between nodules and healthy parenchyma for both attenuation and dark-field modalities. High-resolution micro-CT and pathological examinations were used to crosscheck and validate our results. Paired t-test was used for comparing the ability of dark-field and attenuation modalities in pulmonary nodule detection. RESULTS: The nodules were shown as a signal decrease in the dark-field modality and a signal increase in the attenuation modality. The number of nodules increased from day 8 to day 16, indicating disease progression. The detectability indices of dark-field modality were higher than those of attenuation modality (p = 0.025). CONCLUSIONS: Compared with the standard attenuation CT, the dark-field CT improved the detection of lung nodules. RELEVANCE STATEMENT: Dark-field CT has a higher detectability index than conventional attenuation CT in lung nodule detection. This technique could improve the early diagnosis of lung cancer. KEY POINTS: • Lung cancer progression was observed using x-ray dark-field CT. • Dark-field modality complements with attenuation modality in lung nodule detection. • Dark-field modality showed a detectability index higher than that attenuation in nodule detection.

Transcriptomic analysis reveals that IL-1R8/Sigirr is a novel macrophage migration regulator and suppresses macrophage proliferation through p38 MAPK signaling pathway.

IL-1R8, also known as the Single immunoglobin interleukin-1 (IL-1)-related receptor (Sigirr), has been demonstrated as a negative regulator of IL-1R and Toll-like receptor (TLR) downstream signaling pathways and inflammation. However, the role of IL-1R8 in macrophage migration and proliferation remains unknown. Here we investigated transcriptome profiles of WT and Il1r8-deficient splenocytes and found that innate immunity and cell migration related pathways were significantly correlated with IL-1R8 expression. Cell migration-related genes were downregulated in Il1r8-/- splenocytes or IL-1R8-depleted RAW264.7 cells. Further experiments revealed that IL-1R8-depleted RAW264.7 cells or Il1r8-/- BMDMs exhibited impaired cell migration. Moreover, we found that IL-1R8 suppresses macrophage proliferation through p38 MAPK signaling pathway. Therefore, our study suggests that IL-1R8 is a new positive regulator for macrophage migration and suppresses macrophage proliferation.

p16 promotes proliferation in cervical carcinoma cells through CDK6-HuR-IL1A axis.

The Cyclin-Dependent Kinase Inhibitor p16 (p16) acts as a tumor suppressor in most cells, but for HPV transformed cervical cancer, in which oncoprotein E7 expressed by human papillomavirus (HPV) mediates the degradation of retinoblastoma protein (Rb), p16 exhibits oncogenic activity. Our study was conducted to study the mechanism underling p16 mediated promoting effect of cell proliferation in cervical cancer cell lines. CCK8 assay and EdU incorporation were conducted to evaluate cell proliferation. Loss-of-function assay was used to silence p16 in Ca Ski and SiHa cells. Next, western blot, qPCR, RNA silencing, luciferase activity assay, run-on assay, mRNA stability assay, RNA immunoprecipitation, co-immunoprecipitation Immunofluorescence were performed to examine the interaction between CDK6, HuR, and IL1A mRNA in p16 mediated proliferation promoting effect. Our results showed that: (1) Silencing p16 inhibited the proliferation of cervical cancer cells by decreasing the half-life of IL1A mRNA in CDK6 dependent manner; (2) The stabilization of IL1A mRNA was regulated by HuR which could be inactivated by p16/CDK6 mediated phosphorylation at Ser202; (3) IL1A mediated the oncogenic activity of p16 in cervical carcinoma cell lines. In conclusion, p16 promotes proliferation in cervical carcinoma cells through CDK6-HuR-IL1A axis.

Involvement of the Wnt/ß-Catenin signaling pathway in the heterogenous nuclear ribonucleoprotein K-driven inhibition of proliferation and migration in head and neck squamous cell carcinoma.

The abnormal upregulation of heterogeneous nuclear ribonucleoprotein K (hnRNP K) expression levels were reported to be involved in the progression of various types of cancer. Therefore, it is hypothesized that hnRNP K may serve as a useful diagnostic marker and antitumor target; however, only a few studies to date have investigated the exact role of hnRNP K in head and neck squamous cell carcinoma (HNSCC) and the potential downstream signaling pathway involved. The present study aimed to identify the roles of hnRNP K in the proliferation and migration of HNSCC, and the possible signaling pathways hnRNP K may be associated with in HNSCC. hnRNP K expression levels in clinical HNSCC samples were analyzed using the Oncomine and UALCAN databases, and its association with the survival of patients with HNSCC was analyzed using the tumor-immune system interactions database. Short hairpin RNA targeting hnRNP K was transfected into the CAL-27 cell line to establish HNSCC cells with stable hnRNP K-knockdown. Cell viability was analyzed using a Cell Counting Kit-8 assay and an absolute count assay, and cell proliferation was measured using 5-ethynyl-2'-deoxyuridine incorporation and colony formation assays. Migratory ability of cells was analyzed using wound healing assay and transwell assay. The growth of xenografts derived from hnRNP K-knockdown cells was also evaluated, and bioinformatics analyses were performed using the Gene Ontology and Kyoto Encyclopedia for Genes and Genomes databases to determine the possible downstream signaling pathways of hnRNP K. Furthermore, the status of the Wnt/ß-Catenin signaling pathway in hnRNP K-knockdown cells mediated by small interfering RNA was determined using reverse transcription-quantitative PCR and western blotting. The results revealed that the expression levels of hnRNP K were upregulated in HNSCC cell lines and tissues. Moreover, the upregulation of hnRNP K expression levels was associated with poor survival of patients with HNSCC. The knockdown of hnRNP K also decreased HNSCC cell proliferation and migration, and inhibited tumor growth in nude mice. Bioinformatics analyses identified the Wnt/ß-Catenin signaling pathway as a possible downstream signaling pathway of hnRNP K. Knockdown of hnRNP K significantly downregulated the expression levels of Wnt/ß-Catenin signaling pathway-related proteins; while with knockdown of hnRNP K and overexpression of ß-Catenin, the expression levels of Wnt/ß-Catenin signaling pathway-related proteins were partially rescued. In conclusion, the present findings indicated that hnRNP K may serve as a candidate diagnostic biomarker and a promising therapeutic target for HNSCC.

NQO1 Stabilizes p53 in Response to Oncogene-Induced Senescence.

Cellular senescence is a state of permanent cellular arrest that provides an initial barrier to cell transformation and tumorigenesis. In this study, we report that expression of NAD(P)H: quinone oxidoreductase 1 (NQO1), a cytoplasmic 2-electron reductase, is induced during oncogene-induced senescence (OIS). Depletion of NQO1 resulted in the delayed onset of senescence. In contrast, ectopic expression of NQO1 enhanced the senescence phenotype. Analysis of the mechanism underlying the up-regulation of NQO1 expression during senescence identified that NQO1 promotes p53 accumulation in an MDM2 and ubiquitin independent manner, which reinforces the cellular senescence phenotype. Specifically, we demonstrated that NRF2/KEAP1 signaling regulates NQO1 expression during OIS. More importantly, we confirmed that depletion of NQO1 facilitates cell transformation and tumorigenesis, which indicates that NQO1 takes part in the senescence barrier and has anti-oncogenic properties in cell transformation.