Cellular Proliferation In Cells Research Articles

Vitamin D controls cancer by regulating telomere and telomerase

Deficiency of vitamin D in the body may cause many disorders and diseases including cancer. Vitamin D receptors are one of the most important nuclear receptors responsible for transcription and cellular proliferation and thus affects telomere and telomerase. Telomerase enzymes is responsible for transcription and copies the telomere. The process of telomere copying leads to absence of cell death and thus causes the cellular proliferation of cells within the body. If maintained at normal level, vitamin D regulates and controls the processes of cellular replication and proliferation leading to control and regulation of rate of secretion of telomerase which in turn maintains the appropriate telomere length. Since telomerase is one of the primary factors of cancer spread, telomerase regulation and control can lead to cancer control. Therefore, by maintaining normal vitamin D level in the body DNA can be protected from damage.

Abstract 3353: ZNF414 as a functionally relevant transcription factor in pancreatic and breast cancer cells

Abstract Background: The Zinc Finger Protein 414 (ZNF414) is a member of the krüppel C2H2-type zinc-finger protein family. ZNF414 is a cargo protein for Karyopherin α7 (KPNA7), a nuclear importer expressed during embryogenesis, absent in most adult tissues but re-expressed in cancer cells. KPNA7 is involved in promoting proliferation and maintaining nuclear morphology in several breast and pancreatic cancer cell lines. Similar effects on cell growth have been evidenced for ZNF414 using in vitro knock-down experiments. Other than this, the function of ZNF414 remains uncharacterized but, as a zinc finger protein with nuclear localization, it is likely to act as a transcription factor. This study aimed at identifying target genes and DNA binding motifs of ZNF414 in pancreatic and breast cancer cells. Methods: We used next generation sequencing methods on Hs700T and MCF-7 cell lines. RNA-seq was used to identify genes regulated by ZNF414 and ChIP-exo and ATAC-seq analyses to uncover its genomic binding regions. Samples for RNA-seq were collected 12h and 24h after transfection with siRNAs targeting ZNF414. For ChIP-exo and ATAC-seq experiments, cells were transfected to transiently overexpress V5-tagged ZNF414. Results: RNA-seq data analyses revealed 33 and 296 differentially expressed genes (DEGs) in Hs700T cells at 12h and 24h time points, respectively. The corresponding amounts of DEGs in MCF-7 cell line were 177 and 556. There were 23 and 108 DEGs in common to both cell lines at 12h and 24h, respectively. Interestingly, gene ontology analyses revealed enrichment of many functional categories related to cellular proliferation in both cell lines, providing a molecular explanation for the observed ZNF414-elicited phenotype. ChIP-exo data was processed using MACE tool and then combined with the ATAC-seq open chromatin signal to identify the most reliable peaks. We looked at the genomic location of these peaks and observed clear enrichment in the promoter and 5'UTR regions, indicating that ZNF414 is a classical transcription factor. Using MEME for de novo motif discovery analyses, we identified several putative binding motifs common to both cell lines, some of which were also found in promoters of DEGs. Conclusion: This study uncovered the transcriptional regulation that underlies the role of ZNF414 as inducer of cellular proliferation in pancreatic and breast cancer cells. Citation Format: Alejandra Rodríguez Martínez, Elisa M. Vuorinen, Anastasia Shcherban, Nina K. Rajala, Matti Nykter, Anne Kallioniemi. ZNF414 as a functionally relevant transcription factor in pancreatic and breast cancer cells [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 3353.

Abstract 4376: Tumor treating fields (TTFields) decrease proliferation of patient-derived lung cancer brain metastasis cells in vitro

Abstract Up to 40% of all non-small cell lung cancer (NSCLC) patients will develop brain metastases during the course of their disease, with ~20-25% of patients presenting with brain metastases at the time of their initial lung cancer diagnosis. For the latter patient population, median survival is a dismal 8 months. Systemic therapies are typically ineffective at treating the brain metastases, even in cases when the extracranial disease responds to the therapy. Clinical trials utilizing TTFields therapy in patients with lung cancer brain metastases are underway. For these trials, TTFields are delivered at 150 kHz, as that is the frequency that has been determined for the treatment of primary lung cancer. In contrast, for the FDA-approved treatment of the most common malignant primary brain tumor, glioblastoma, TTFields are delivered at 200 kHz. Therefore, in this study, a patient-derived lung cancer brain metastatic cell line was assessed to compare the response to in vitro TTFields application at either 150 or 200 kHz compared to untreated control cells. Methods: Use of patient tumor tissue for this study was approved by the Wayne State University Institutional Review Board and written informed consent was obtained from the patient. An adenocarcinoma lung cancer brain metastasis (from a patient that presented with the brain metastasis at the time of diagnosis) was collected immediately following microsurgical resection. A single-cell suspension from the tumor tissue was prepared by enzymatic and mechanical disruption. After 7 passages in vitro, cells were plated on plastic coverslips (10,000 each) in DMEM/F12 media supplemented with 10% fetal bovine serum. TTFields were applied at ~1.6 V/cm at 150 or 200 kHz (groups n=4-5) with one control group. Culture media was replaced every day. After 10 days of in vitro TTFields application, cell proliferation was assessed with the XTT assay. Control vs. TTFields-treated groups were compared with two-tailed t-tests. Results: The 10-day TTFields treatment resulted in significantly reduced cellular proliferation in the cells that received 150 kHz TTFields (0.220±0.006; mean±SEM) compared to the control cells (0.250±0.009; p=0.0237) with no statistical difference between the control and the cells that received 200 kHz TTFields (0.230±0.008; p>0.05). Conclusions: Application of TTFields in vitro at 150 kHz reduced cellular proliferation in patient-derived lung cancer brain metastasis cells, with no reduction of proliferation after application of TTFields at 200 kHz. This is the first report on the in vitro effects of TTFields in a patient-derived NSCLC brain metastasis cell line. Citation Format: Sharon K. Michelhaugh, Sam Kiousis, Neil V. Klinger, Sandeep Mittal. Tumor treating fields (TTFields) decrease proliferation of patient-derived lung cancer brain metastasis cells in vitro [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 4376.

Modulation of expression of the nuclear receptor NR0B2 (small heterodimer partner 1) and its impact on proliferation of renal carcinoma cells.

Mammalian nuclear receptors (NRs) are transcription factors regulating the expression of target genes that play an important role in drug metabolism, transport, and cellular signaling pathways. The orphan and structurally unique receptor small heterodimer partner 1 (syn NR0B2) is not only known for its modulation of drug response, but has also been reported to be involved in hepatocellular carcinogenesis. Indeed, previous studies show that NR0B2 is downregulated in human hepatocellular carcinoma, suggesting that NR0B2 acts as a tumor suppressor via inhibition of cellular growth and activation of apoptosis in this tumor entity. The aim of our study was to elucidate whether NR0B2 may also play a role in other tumor entities. Comparing NR0B2 expression in renal cell carcinoma and adjacent nonmalignant transformed tissue revealed significant downregulation in vivo. Additionally, the impact of heterologous expression of NR0B2 on cell cycle progression and proliferation in cells of renal origin was characterized. Monitoring fluorescence intensity of resazurin turnover in RCC-EW cells revealed no significant differences in metabolic activity in the presence of NR0B2. However, there was a significant decrease of cellular proliferation in cells overexpressing this NR, and NR0B2 was more efficient than currently used antiproliferative agents. Furthermore, flow cytometry analysis showed that heterologous overexpression of NR0B2 significantly reduced the amount of cells passing the G1 phase, while on the other hand, more cells in S/G2 phase were detected. Taken together, our data suggest that downregulation of NR0B2 may also play a role in renal cell carcinoma development and progression.

Nucleolar organizer regions of oral epithelial cells in crack cocaine users.

The health risks of crack cocaine smoking on the oral mucosa has not been widely researched and documented. The purpose of this study was to analyze the proliferative activity of oral epithelial cells exposed to crack cocaine smoke using silver nucleolar organizer region (AgNOR) staining. Oral smears were collected from clinically normal-appearing buccal mucosa by liquid-based exfoliative cytology of 60 individuals (30 crack cocaine users and 30 healthy controls matched for age and gender) and analyzed for cytomorphologic and cytomorphometric techniques. Crack cocaine users consumed about 13.3 heat-stable rocks per day and the time consumption of the drug was of 5.2 (± 3.3) years. Mean values of AgNOR counting for case and control groups were 5.18 ± 1.83 and 3.38 ± 1.02 (P<0.05), respectively. AgNOR area and percentage of AgNOR-occupied nuclear area were increased in comparison with the control (P<0.05). There was no statistically significant difference in the mean values of the nuclear area between the groups (P>0.05). This study revealed that crack cocaine smoke increases the rate of cellular proliferation in cells of normal buccal mucosa.

The effects of 1,2-dichloroethane on the cellular proliferation, cellular cycle and apoptosis of SW620 cells in vitro

To explore the effects of 1,2-dichloroethane (1,2-DCE) on the cellular proliferation, cellular cycle and apoptosis of SW620 cells in vitro. SW620 cells were exposed to 1,2-DCE at different concentrations for 0.5 and 1 h. MTT assay was used to detect the relative number and relative viability, the low cytometry (FCM) assay was utilized to measure the cell cycle and apoptosis. The results of MTT assay showed that the cellular relative viability decreased with the 1,2-DCE's dose and exposure time. Compared with the DMSO group, the relative cellular viability of cells exposed to 1,2-DCE at the doses of 75, 100, 125, 150, 175, 200 µmol/L for 1 h decreased (P<0.05 or P<0.01). Compared with the groups exposed to 1,2-DCE for 0.5 h, the relative cellular viability of cells exposed to 175 µmol/L 1,2-DCE for 1 h decreased significantly (P<0.01). IC(50) of cellular proliferation in cells exposed to 1,2-DCE for 0.5 h was 89.41 µmol/L, and 95% confidence interval was 85.23 to 93.79 µmol/L. IC(50) of cellular proliferation in cells exposed to 1,2-DCE for 1 h was 87.68 µmol/L, and 95% confidence interval was 83.71 to 91.82 µmol/L. The results of FCM indicated that compared with the control group, the G(0)/G(1) phase in groups exposed to 1,2-DCE at the doses of 25, 50, 100, 150 and 200 µmol/L for 1 h decreased significantly (P<0.05 or P<0.01), the S phase in groups exposed to 1,2-DCE at the doses of 25, 50 and 100 µmol/L for 1 h reduced significantly (P<0.05 or P < 0.01), the G(2)/M phase in groups exposed to 1,2-DCE at the doses of 25, 50, 100, 150 and 200 µmol/L for 1 h increased significantly (P<0.05 or P<0.01). However, 1,2-DCE could not induce apoptosis of SW620 cells. 1,2-DCE could inhibit the proliferation of SW620 cells, and arrest SW620 cells at G(2)/M phase, but could not induce the apoptosis of SW620 cells in vitro.

Insulin Receptor Substrate-4 Enhances Insulin-like Growth Factor-I-induced Cell Proliferation

The insulin receptor substrates (IRSs)-1-4 play important roles in signal transduction emanating from the insulin and insulin-like growth factor (IGF)-I receptors. IRS-4 is the most recently characterized member, which has been found primarily in human cells and tissues. It interacts with SH2-containing proteins such as phosphatidylinositol 3'-kinase (PI3K), Grb2, Crk-II, and CrkL. In this study, we transfected IRS-4 in mouse NIH-3T3 cells that overexpress IGF-I receptors. Clones expressing IRS-4 showed enhanced cellular proliferation when cells were cultured in 1% fetal bovine serum without added IGF-I. Addition of IGF-I enhanced cellular proliferation in cells overexpressing the IGF-I receptor alone but had an even greater proliferative effect in cells overexpressing both the IGF-I receptors and IRS-4. When etoposide and methylmethane sulfonate (MMS), both DNA damaging agents, were added to the cells, they uniformly induced cell cycle arrest. Fluorescence-activated cell sorter analysis demonstrated that the arrest of the cell cycle occurred at the G(1) checkpoint, and furthermore no significant degree of apoptosis was demonstrated with the use of either agent. In cells, overexpressing IGF-I receptors alone, IGF-I addition enhanced cellular proliferation, even in the presence of etoposide and MMS. In cells overexpressing IGF-I receptors and IRS-4, the effect of IGF-I in overcoming the cell cycle arrest was even more pronounced. These results suggest that IRS-4 is implicated in the IGF-I receptor mitogenic signaling pathway.

The loss of expression of transforming growth factor-beta receptors correlates with the histopathologic tumor grade in bladder transitional cell carcinoma patients.

Transforming growth factor-beta (TGF-beta), a pleiotropic growth factor, is a potent inhibitor of cellular proliferation in cells of epithelial origin. Recently, it has been suggested that a loss of sensitivity to TGF-beta through a loss of expression of TGF-beta receptors T beta R-I and T beta R-II--is associated with tumor initiation and progression. Therefore, to investigate the relationship between TGF-beta receptors expression and carcinogenesis of bladder TCC, this study examined the expression of T beta R-I and T beta R-II in 46 bladder TCC patients using immunohistochemistry. Since histopathological grade is a widely accepted marker of prognosis, the results were compared in relation to the three grades of bladder TCC. The results demonstrated that the loss of TGF-beta receptors expression is associated with increasing histopathological grades of bladder TCC. Specifically, both T beta R-I and T beta R-II were readily detected in all 10 normal bladder mucosa specimens. Likewise, all 6 specimens of grade I TCC samples expressed high levels of both TGF-beta receptors. However, among grade II TCC samples, T beta R-I and T beta R-II were detected in 78% and 89%, respectively: among grade III TCC samples, T beta R-I and T beta R-II were detected in 45% and 41%, respectively. These results suggested that loss of sensitivity to TGF-beta may play a role in the progression of TCC from low to high grade disease.

Response of Lens Epithelial Cells to Hydrogen Peroxide Stress and the Protective Effect of Caloric Restriction

Hydrogen peroxide (H2O2) has been reported to be present at significant levels in the lens and aqueous humor in some cataract patients and suggested as a possible source of chronically inflicted damage to lens epithelial (LE) cells. We measured H2O2effects on bovine and mouse LE cells and determined whether LE cells from old calorically restricted mice were more resistant to H2O2-induced cellular damage than those of same age ad libitum fed (AL) mice. Bovine lens epithelial cells were exposed to H2O2at 40 or 400 μM for 2 h and then allowed to recover from the stress. The cells were assayed for DNA damage, DNA synthesis, cell viability, cell morphology, response to growth stimuli, and proliferation potential. Hydrogen peroxide-treated cells showed an increased DNA unwinding 50% greater than that for untreated controls. These DNA strand breaks appeared to be almost completely rejoined by 30 min following removal of the cells from a 2-h exposure. The 40 μM exposure did not produce a significantly lower DNA synthesis rate than the control, it responded to growth factor stimuli, and it replicated as did the control cells after removal of H2O2. The 400 μM H2O2severely affected DNA synthesis and replication, as shown by increased cell size and by markedly reduced clonal cell growth. The cells did not respond to growth stimulation by serum or growth factors and lost irreversibly the capacity to proliferate. The responses of LE cells from old adlib diet (AL) and calorically restricted (CR) mice to H2O2were significantly different. Exposure of LE cells to 20, 40, or 100 μM H2O2for 1 h induces a significant loss of cellular proliferation in cells from old AL mice. LE cells from long-term CR mice of the same strain and age were more resistant to oxidative damage at all three concentrations of H2O2than those of both old and young AL mice and showed a significantly higher proliferation potential following treatment. It is concluded that CR results in superior resistance to reactive oxygen radicals in the lens epithelium.

The effects of histamine H2 receptor antagonists on melanogenesis and cellular proliferation in melanoma cells in culture

B16-C3 murine melanoma, A375P human melanotic melanoma, and C32 human amelanotic melanoma cells were incubated in the presence of (0–4mM) H2-antagonists, ranitidine and cimetidine. Cell proliferation, tyrosinase activity and melanin content were monitored. H2-antagonists stimulated tyrosinase activity and melanin accumulation in B16-C3 cells in a dose- and time-dependent manner. Stimulation of enzyme activity and pigment production was accompanied by inhibition of cellular proliferation in B16-C3 cells. The inhibitory concentration of cimetidine was approximately 2-fold higher than that of ranitidine. H2-antagonists failed to stimulate melanogenesis in A375P or C32 cells, but inhibited cellular proliferation in both cell lines. These results are the first demonstration of H2-antagonist induced phenotypic changes in malignant melanoma cells in vitro, and represent a novel mechanism for the previously described in vivo antitumor effects of these agents.

Activation of Na+/H+ exchange and the expression of cellular proto-oncogenes in mitogen- and phorbol ester-treated lymphocytes.

It has been suggested that an intracellular alkalinization, resulting from stimulation of Na+/H+ exchange, is a necessary step and perhaps the signal leading to cellular proliferation in cells stimulated by mitogens. This hypothesis was tested by measuring the early stages of the proliferative cascade in cells where antiport activity was precluded by omission of Na+ or by the addition of potent amiloride analogs. To circumvent possible nonspecific effects due to long incubations under these conditions, an early response to mitogens, the increased level of c-fos mRNA, was monitored. In rat thymic lymphocytes, the increase in the level of c-fos RNA induced by the combination of 12-O-tetradecanoylphorbol 13-acetate and ionomycin was unaffected by inhibition of the antiport with 5-(N-ethyl-N-propyl)amiloride. Increased c-fos RNA was also observed in the absence of Na+ and when alkalinization was prevented by means of nigericin. Similar results were obtained with phytohemagglutinin-stimulated human T lymphocytes. Moreover, although the lectin stimulated the antiport in these cells, an alkalinization was not observed, due to the concomitant occurrence of an acidifying process. It was concluded that the stimulation of the Na+/H+ antiport that accompanies the addition of mitogens is neither sufficient nor necessary for the initiation of cellular proliferation.