The anti-neoplastic effects of metformin modulate the acquired phenotype of fbroblast cells in the breast cancer-normal fbroblast co-culture system

Intracellular communications between breast cancer and fibroblast cells were reported to be involved in cancer proliferation,growth,and therapy resitance.The hallmarks of cancer fibroblast interactions,consisting of caveolin 1(Cav1)and mono-carboxylate ransporter 4(MCT4)(metabolic coupling markers),along with IL-6,TGFB,and lactate secretion,are considered robust biomarkers predicting recurrence and metastasis.In order to promote a novel phenotype in normal fibroblasts,we predicted that breast cancer cells could be able to cause loss of Cavl and increase of MCT4,as well as elevate IL 6 and TGF in nearby nomal fibroblasts.We created a co culture model using breast cancer(4T1)and normal fibroblast(NIH3T3)cell lines cultured under specific experimental conditions in order to directly test our theory.Moreover,we show that long-term co-culture of breast cancer cells and normal fibroblasts promotes loss of Cavl and gain of MCT4 in adjacent fibroblasts and increase lactate secretion.These results were validated using the monoculture of each group separately as a control.In this system,we show that me tformin inhibits IL-6 and TGFB secretion and re expresses Cavl in both cells.However,MCT4 and lactate stayed high after treatment with metformin.In conclusion,our work shows that co-culture with breast cancer cells may cause signifcant alterations in the phenotype and secretion of normal fibroblasts.Metformin,however,may change this state and affect fibroblasts'acquired phenotypes.Moreover,mitochondrial inhibition by metformin after 8 days of treatment,signi ficantly hinders tumor growth in mouse model of breast cancer.

The involvement of signaling activation of protein kinase C in gadolinium chloride-induced cell survival and cell cycle progression in NIH3T3 cells

In the present study, we investigated the activation of protein kinase C （PKC） family in mouse embryonic fibroblast NIH3T3 cells using gadolinium chloride as a representative lanthanide ion. With live cell imaging system and confocal laser scanning microscopy, we found that the treatment of 50 μM GdCI3 promoted cell survival under the condition of serum-starvation. Moreover, better cell attachment and cytoskeleton reorganization were also observed. Additionally, GdC13 treatment resulted in the phosphorylation of PKC family at different time points. Furthermore, bisindolylmaleimide （a PKCpan inhibitor） could efficiently reduce the level of phosphorylated PKCpan （βIISer660）, alleviating ERK activation induced by GdC13. This finding indicated that the PKC activation was involved in GdC13-induced MAPK/ERK signaling and thus might contribute to GdClβ-indueed cell cycle progression and cell survival.

Effects of Panax Notoginseng Saponins on Proliferation and Differentiation in NIH3T3 Cells

Objective： To investigate the effects of Panax notoginseng saponins （PNS） on the proliferation and differentiation in NIH3T3 cells. Methods： NIH3T3 cells were treated by various concentrations of PNS 0, 0.05, 0.10, 0.20, and 0.40 g/L. The vitality and proliferation potential of cells were detected by 3-（4,5-dimethylthiazol- 2-yl）-2, 5-diphenyltetrazolium bromide （MTT） assay, the alkaline phosphatase （ALP） activity was measured by p-nitrophenyl phosphate （pNPP） assay, and the mineralization formation ability was tested for the cellular differentiation toward osteoblast, as well as the expression level of phosphorylated extrecellular signal-regulated kinasel/2（P-ERK1/2）, extracellular signal-regulated kinasel/2 （ERK1/2） protein kinase was analyzed by Western blot with total cell lysate of NIH3T3 cells treated by PNS. Results： Both MTT and pNPP assay showed that optical density （OD） values were increased in response to PNS treatment at a dose-dependent pattern. The mineralization formation ability was enhanced in PNS-treated NIH3T3 cells compared with untreated cells. Meanwhile, the expression level of P-ERK1/2 protein kinase was up-regulated in PNS-treated NIH3T3 cells, while, the expression level of ERK1/2 protein kinase revealed no obvious difference with or without PNS treated cells. Conclusion： PNS could pay a role to promote the proliferation and differentiation in NIH3T3 cells by means of up-regulation of P-ERK1/2 protein kinase.

Cell transformation as aberrant differentiation: Environmentally dependent sportaneous transformation of NIH 3T3 cells

NIH 3T3 cells, a mouse fibroblast cell line used as routine target cells for transfection experiments, undergo spontaneous transformation in our experiments after they form a confluent sheet in medium containing fetal bovina serum (FBS) or lower coneentrafcion of calf serum (CS). The transformation takes the form of foci of multiplying cells among the surrounding cells which have stopped cell division. However, no focus of transformed cells could be seen in medium containing high concentration (10%) of OS. Further experiments indicated that the frequency of transformation is highly dependent on the concentration of serum and the transformation in OS is changeable when the cells are passaged in FBS. 8H-thymidine autoradiography has been proved to be a sensitive measurement indicator for foous formation. Our results suggest that the high frequency of transformation and its dependence on confmenoy as well as on medium composition are characteristics of cell differentiation rather than mutation. The role of the NIH 3T3 cell line as a cancer-initiated cell population and its accelerated transformation by rat oncogene might be considered as a form of tumor promotion is discussed.

ELECTRON MICROSCOPIC OBSERVATION OF SIMIAN SARCOMA VIRUS TRANSFORMED NIH 3T3 CELLS IN VITRO

For electronic microscopic observation, we found SSV-transformed NIH 3T3 cells were different from non-transformed cells. In SSV-transformed NIH 3T3 cells nuclei cytoplasma ratio was increased and in cytoplasma the ribosomes (polyribosomes were attached to the swollen rough endoplasmic reticulum. It was likely that ribosomes were lined together functionally and structionally to produce specific protein (PDGF-like protein).

Regulated expression of TATA-binding protein-related factor 3(TRF3)during early embryogenesis

RNA polymerase （Pol） Ⅱ transcription persists in TATA-box-binding protein （TBP）^-/- mutant mouse embryos, indicating TBP-independent mechanisms for Pol Ⅱ transcription in early development. TBP-related factor 3 （TRF3） has been proposed to substitute for TBP in TBP^-/- mouse embryos. We examined the expression of TRF3 in maturing oocytes and early embryos and found that TRF3 was co-expressed with TBP in the meiotic oocytes and early embryos from the late one-cell stage onward. The amounts of TBP and TRF3 changed dynamically and correlated well with transcriptional activity. Chromatin immunoprecipitation （CHIP） assay revealed that different gene promoters in mouse embryonic stem （ES） cells recruited TRF3 and TBP selectively. Comparative analyses of TRF3 and TBP during cell cycle showed that both factors proceeded through cell cycle in a similar pace, except that TRF3 was slightly delayed than TBP in entering the nucleus when cells were exiting the M-phase. Data from expression and biochemical analyses therefore support the hypothesis that TRF3 plays a role in early mouse development. In addition, results from co-localization study suggest that TRF3 may be also involved in Pol Ⅰ transcription.

Lanthanum chloride promotes proliferation of NIH 3T3 cells via cell cycle machinery

Lanthanum ions （La3＋） have been reported to exert profound effects on the proliferation of NIH 3T3 mouse embryonic fibroblasts. In the present studies, the pro-proliferative effect of La3＋ on NIH 3T3 cells was further characterized, and its impacts on the cell cycle kinetics were analyzed in detail by cell cycle arrest-and-release and pulse BrdU-labeling and chasing experiments. The results show that La3＋ promoted the proliferation of NIH 3T3 cells after 12 h and the ECs0 was 2.4 ktM after 48 h. Such effect was also confirmed by enhanced BrdU incorporation. La3＋ stimulated more cells to pass through the G1/S checkpoint into S phase, but did not change the length of cell cycle. Furthermore, La3＋-treatment increased the protein levels and nuclear localization of cyclin D 1 and c-Myc, two key regulators of G1/S checkpoint, as demonstrated by immunostaining. The pro-proliferative effects of La3＋ share striking similarity with that of Gd3＋, and provided new information regarding the cellular biological activities of lanthanides.

Lanthanum Chloride Promoted Proliferation with Enhanced S-phase Entry and Inhibited Potassium Currents of NIH 3T3 Cells

The effects of La^3＋ on proliferation, cell cycles, apoptosis and ion channels were investigated in mouse embryo fibroblast NIH 3T3 cells and its possible mechanisms were explored. Our data showed that La^3＋ promoted cell proliferation with increased S-phase entry and inhibited the outward potassium currents in a concentration-dependent manner in NIH 3T3 cells. La^3＋ and Ca^2＋ had synergistic effect on cell proliferation and cell cycles. It showed that Ca^2＋ was needed for La^3＋ promoted cell cycle progression. Using the whole-cell voltage-clamp technique, we found that La^3＋ blocked the outward potassium current in a Lanthanum ions can increase intracellular Ca^2＋ concentration concentration-dependent manner in NIH 3T3 cells. through inhibition of potassium currents, which induce a series of physiological changes and improve proliferation of cells. This may be one of the molecular mechanisms of lanthanum ions induced cell proliferation. The present work provides a new perspective for understanding the biological and toxicological effects of lanthanum.

Hepatitis C virus nonstructural protein NS3 and telomerase activity

To study the effect of hepatitis C virus nonstructural protein NS 3 (HCV NS3) on telomerase activity and carcinogenesis Methods Streptavidin peroxidase (SP) conjugated method was used to detect the expressio n of HCV NS 3 protein in NIH3T3 cells transfected with plasmid pRcHCNS 3 5’ and pRcHCNS 3 3’ Telomerase activity was detected by an in situ telomerase a ctivity labeling method, telomeric repeat amplification protocol polymerase chai n reaction (TRAP PCR) and telomerase PCR enzyme linked immunosorbent assay (ELI SA) technology in the transfected and non transfected NIH3T3 cells Results HCV NS 3 protein was expressed in the NIH3T3 cells transfected with plasmid pR cHCNS 3 5’ expressing HCV NS 3 C terminal deleted protein or with plasmid pR cHCNS 3 3’ expressing HCV NS 3 N terminal deleted protein The positive sig nal of HCV NS 3 protein was localized in the cytoplasm of NIH3T3 cells, and th e signal intensity of the former was stronger Telomerase activity in NIH3T3 c ells transfected with plasmid pRcHCNS 3 5’ was stronger than that in NIH3T3 c ells transfected with plasmid pRcHCNS 3 3’ ( P 【0 01), whereas telomerase a ctivity in NIH3T3 cells transfected with plasmid pRcCMV or untreated NIH3T3 ce lls was weaker than that in NIH3T3 cells transfected with plasmid pRcHCNS 3 3 ’ ( P 【0 05) The expression level of HCV NS 3 protein was significantly co rrelated with the strength of telomerase activity ( P 【0 05) The results ob tained by in situ telomerase activity labeling corresponded to the results by te lomerase PCR ELISA technology Conclusions HCV NS 3 protein may activate telomerase through endogenous mechanism to induce host cell transformation The effect of HCV NS 3 C terminal deleted protein on telomerase activity in the host cell may be stronger than that of HCV NS 3 N terminal deleted protein In situ telomerase activity labeling was a reliabl e technology for studying pathological morphology and telomerase activity in tis sues and cells