Knockdown of STIM1 inhibits 6-hydroxydopamine-induced oxidative stress through attenuating calcium-dependent ER stress and mitochondrial dysfunction in undifferentiated PC12 cells.

Stromal interaction molecule (STIM) proteins are parts of elaborate eukaryotic Ca(2+) signaling systems and are considered to be important players in regulating neuronal Ca(2+) homeostasis under normal ageing and pathological conditions. Here, we investigated the potential role of STIM1 in 6-hydroxydopamine (6-OHDA)-induced toxicity in undifferentiated PC12 cell lines. Cells exposed to 6-OHDA demonstrated alterations in the generation of reactive oxygen species (ROS) in a Ca(2+)-dependent manner. Downregulation of STIM1 expression by specific small interfering RNA (siRNA) attenuated apoptotic cell death, reduced intracellular ROS production, and partially prevented the impaired endogenous antioxidant enzyme activities after 6-OHDA treatment. Furthermore, STIM1 knockdown significantly attenuated 6-OHDA-induced intracellular Ca(2+) overload by inhibiting endogenous store-operated calcium entry (SOCE). The effect of STIM1 siNRA on SOCE was related to orai1 and L-type Ca(2+) channels, but not to transient receptor potential canonical type 1 (TRPC1) channel. In addition, silencing of STIM1 increased the Ca(2+) buffering capacity of the endoplasmic reticulum (ER) in 6-OHDA-injured cells. ER vacuoles formed from the destruction of ER structural integrity and activation of ER-related apoptotic factors (CHOP and Caspase-12) were partially prevented by STIM1 knockdown. Moreover, STIM1 knockdown attenuated 6-OHDA-induced mitochondrial Ca(2+) uptake and mitochondrial dysfunction, including the collapse of mitochondrial membrane potential (MMP) and the decrease of ATP generation. Taken together, our data provide the first evidence that inhibition of STIM1-meditated intracellular Ca(2+) dyshomeostasis protects undifferentiated PC12 cells against 6-OHDA toxicity and indicate that STIM1 may be responsible for neuronal oxidative stress induced by ER stress and mitochondrial dysfunction in PD.

OCT4 promotes tumorigenesis and inhibits apoptosis of cervical cancer cells by miR-125b/BAK1 pathway.

Octamer-binding transcription factor 4 (OCT4) is a key regulatory gene that maintains the pluripotency and self-renewal properties of embryonic stem cells. Although there is emerging evidence that it can function as oncogene in several cancers, the role in mediating cervical cancer remains unexplored. Here we found that OCT4 protein expression showed a pattern of gradual increase from normal cervix to cervical carcinoma in situ and then to invasive cervical cancer. Overexpression of OCT4 in two types of cervical cancer cells promotes the carcinogenesis, and inhibits cancer cell apoptosis. OCT4 induces upregulation of miR-125b through directly binding to the promoter of miR-125b-1 confirmed by chromatin immunoprecipitation analysis. MiRNA-125b overexpression suppressed apoptosis and expression of BAK1 protein. In contrast, miR-125b sponge impaired the anti-apoptotic effect of OCT4, along with the upregulated expression of BAK1. Significantly, Luciferase assay showed that the activity of the wild-type BAK1 3'-untranslated region reporter was suppressed and this suppression was diminished when the miR-125b response element was mutated or deleted. In addition, we observed negative correlation between levels of BAK1 and OCT4, and positive between OCT4 and miR-125b in primary cervical cancers. These findings suggest an undescribed regulatory pathway in cervical cancer, by which OCT4 directly induces expression of miR-125b, which inhibits its direct target BAK1, leading to suppression of cervical cancer cell apoptosis.

Identification of the motif in versican G3 domain that plays a dominant-negative effect on astrocytoma cell proliferation through inhibiting versican secretion and binding.

This study was designed to investigate the mechanisms by which mutant versican constructs play a dominant-negative effect on astrocytoma cell proliferation. Although a mini-versican or a versican G3 construct promoted growth of U87 astrocytoma cells, a mini-versican lacking epidermal growth factor (EGF) motifs (versicanDeltaEGF) and a G3 mutant (G3DeltaEGF) exerted a dominant-negative effect on cell proliferation. G3DeltaEGF-transfected cells formed smaller colonies, arrested cell cycle at G(1) phase, inhibited expression of cell cycle proteins cdk4 and cyclin D1, and contained multiple nucleoli. In cell surface binding assays, G3 products expressed in COS-7 cells and bacteria bound to U87 cell surface. G3DeltaEGF products exhibited decreased binding activity, but higher levels of G3DeltaEGF products were able to inhibit the binding of G3 to the cell surface. G3DeltaEGF expression inhibited secretion of endogenous versican in astrocytoma cells and also inhibited the secretion of mini-versican in COS-7 cells co-transfected with the mini-versican and G3DeltaEGF constructs. The effect seems to depend on the expression efficiency of G3DeltaEGF, and it occurred via the carbohydrate recognition domain.

Telomerase activity in Papanicolaou smear-negative exfoliated cervical cells and its association with lesions and oncogenic human papillomaviruses.

OBJECTIVE: The goal of this study was to evaluate telomerase activity in exfoliated cervical cells and its association with cytology, pathology, and human papillomavirus (HPV). METHODS: Telomerase activity and HPV DNA sequences were examined in the exfoliated cervical cells from a general population of 245 women aged more than 30 years undergoing routine cervical screening by Papanicolaou smear. The women who were found to have telomerase activity or abnormal cytology in their exfoliated cervical cells were examined for cervical lesions by colposcopy and biopsy. RESULTS: Cytology for our population (mean, 56 years) revealed only one abnormal smear (1/245, 0.4%), in which a cervical intraepithelial neoplasia grade I (CIN I) lesion was found. The exfoliated cervical cells used to prepare the smear were negative for telomerase and contained low-risk HPV DNA. Telomerase activity was found in 16 exfoliated cell samples (16/245, 6.5%); high-risk HPV DNA was found in 9 of these samples (9/16, 56%) and 9 of the biopsy specimens that could be evaluated from patients testing positive for telomerase revealed CIN I lesions (9/11, 82%). CONCLUSIONS: Telomerase activity is often associated with high-risk HPV infection and it is suggested that telomerase assay can help to detect occult cervical lesions.

Telomerase activation in cervical neoplasia.

OBJECTIVE: To examine the critical point at which telomerase activation occurs in the course of cervical carcinogenesis. METHODS: Telomeric repeat assay protocol was used to measure telomerase activity in cell samples obtained from 155 Japanese women with various cervical conditions: normal cytology (n = 62), cervical intraepithelial neoplasia (CIN) (n = 63), and invasive squamous cell carcinoma (n = 30). RESULTS: Telomerase activity was detected in five (8%) women with normal cytology, in 26 (41%) patients with CIN (26% of patients with CIN I, 35% with CIN II, and 68% with CIN III), and in 29 (97%) patients with invasive carcinoma. Telomerase activation was significantly more frequent in CIN than in normal cervices (P < .001), and the positive rate in CIN III was significantly higher than that in CIN I (P < .01) and CIN II (P < .05). Furthermore, telomerase activation was significantly more frequent in invasive carcinoma than in CIN III (P < .01). CONCLUSION: Our findings suggest that telomerase activation is a relatively early event in cervical carcinogenesis and correlates well with grade of cervical lesion.

Telomerase activation in in vitro and in vivo cervical carcinogenesis.

Telomerase activity is found in the majority of human cancers, but not in most normal tissues. It is generally accepted that there is a multistep process in human carcinogenesis. Studying the role of telomerase activation in this process may provide new information to further our understanding of the pathological process of clinical lesions. In the present study, telomerase activity was found in HPV-immortalized and cigarette smoke condensate (CSC)-transformed malignant cell lines established in a cervical carcinogenesis model and in cell lines derived from cervical intraepithelial neoplasias (CINs) and carcinomas. With exfoliated cell samples, telomerase activity was detected in 3 of 41 (7%) normal cervices, 10 of 25 (40%) CINs, and all 20 (100%) carcinomas. Telomerase activation was significantly higher in CINs than in normal cervices (chi2 = 7.42, P < 0.01) and was much higher in invasive carcinomas than in CINs (chi2 = 18.00, P < 0.005). Our observations suggest that telomerase activation is a relatively early-stage event in cervical carcinogenesis, and this activation is associated with the initiation and progression of cervical lesions. Detection of telomerase activity may serve as a tool for diagnosis and prognosis of cervical neoplasias.

Telomerase activity in gynecologic tumors.

The standard telomeric repeat assay protocol (TRAP) was used to examine telomerase activity in 16 ovarian tumors, 16 cervical carcinomas, 4 uterine tumors, and 3 vaginal tumors. Telomerase activity was detected in 95% of these tumors, 88% of ovarian malignancies, and 100% of cervical, endometrial, and vaginal malignancies. In contrast, telomerase activity was not evident in normal tissues or in benign proliferative lesions, such as leiomyomas, condyloma acuminata, and simple endometrial hyperplasia. These results suggest that telomerase activation is associated with immortalization or malignant transformation of gynecologic tumors.

Cytologic changes in two cervical carcinoma cell lines after transfection of the wild-type p53 gene.

BACKGROUND: To examine morphological changes in cervical carcinoma cells after induction of overexpression of wild-type (wt) p53. METHOD: A dexamethazone-inducible wt-p53 cDNA was introduced into two cervical carcinoma cell lines (TMCC-1 and ME180) and morphological changes were examined under a phase contrast microscope and following Papanicolaou staining. RESULTS: TMCC-1 clones obtained by transfection with wt-p53 gene had an altered morphology especially after induction of p53 expression by treatment with dexamethazone. These changes were characterized by cell flattening, multinucleation, micronucleation, and huge giant cells, yet the parental TMCC-1 had none of these morphological changes even after treatment with dexamethazone. Similar cellular changes were observed in ME180 clones obtained by transfection of wt-p53 gene. CONCLUSION: On the basis of our observations, we propose that the growth inhibition induced by expression of wt-p53 in these cervical carcinoma cell lines carrying HPV DNA sequences is not the result of G1 arrest but rather relates to a blockade in the M phase of the cell cycle.

Growth suppression of a cervical cancer cell line (TMCC-1) by the human wild-type p53 gene.

To investigate the effects of human wild-type p53 expression on the proliferation of cervical carcinoma cells, a plasmid, pMO7-hp53, which contains a full-length cDNA of the human wild-type p53 (wt-p53) gene, was transfected into a cell line (TMCC-1) derived from an endocervical type, human papilloma virus-positive adenocarcinoma of the uterine cervix. The exogenous wt-p53 expression induced growth suppression, morphological changes, and loss of anchorage-independent growth of the tumor cells. As the wt-p53 gene apparently plays a negative role in growth regulation of cervical carcinoma cells, this gene may possibly be of some use for treating subjects with a cervical carcinoma.

Simultaneous detection by consensus multiplex PCR of high- and low-risk and other types of human papilloma virus in clinical samples.

A consensus multiplex PCR (CM-PCR) technique was developed to detect high-risk (HPV 16/18), low-risk (HPV 6/11), and over 40 other types of human papillomavirus (HPV), separately but simultaneously, by mixing three pairs of consensus primers in the same PCR mixture, for gene amplification. Simultaneous detection of three groups of HPV DNA provides valuable information for clinical practice and this procedure is simple and convenient for routine laboratory examinations. We detected HPV DNA sequences in plasmid HPV DNA and DNA extracted from tissues of condyloma acuminata and cervical carcinoma and from exfoliated cells of the lower genital tract of healthy Chinese women living in the People's Republic of China. We confirmed that this simple, convenient, and cost-beneficial CM-PCR technique is reliable for the detection of HPV DNA sequences.

Morphology of aged skin.

Despite an overall thinning of the epidermis and focal areas of cytologic atypia, there was no morphologic evidence that the protective function of this tissue was compromised by age. The characteristic morphologic markers associated with the keratinization process were not altered either in appearance or in amounts. A well-formed stratum corneum was present, suggestive that barrier ability is not compromised in senile skin. Whereas alterations in the aged epidermis are slight, the dermal-epidermal changes are marked and have greater physiologic consequences. The major change is a relatively flat dermal-epidermal junction because of retraction of the epidermal papillae as well as the microprojections of basal cells into the dermis. This flattening results in a more fragile tissue that is less resistant to shearing forces. Retraction of the epidermal downgrowths may also explain the loss in proliferative capacity associated with the aged epidermis. The major alterations in the aged dermis concern the architecture of the collagen and elastin networks. Both fibrous components appear more compact because of a decrease in the voids or spaces between the fibers; the spaces resulted from a loss of ground substance. Collagen bundles appear to unravel, and the individual elastic fibers show signs of elastolysis. The net effect of these fibrous rearrangements and alterations is a dermis that is less stretchable, less resilient, more lax, and prone to wrinkling.

Aged skin: a study by light, transmission electron, and scanning electron microscopy.

The fine structural organization of the epidermis, dermal/epidermal junction, and dermis from an unexposed site (upper inner arm) of elderly people was compared with the organization of a similar region of young people. Despite an overall thinning of the epidermis and focal areas of cytologic atypia, the characteristic morphological markers associated with the keratinization process are not markedly altered in appearance or amount. A well-formed stratum corneum consisting of flattened, enucleated horny cells enveloped by a thickened membrane, and intracellular spaces filled with electron-dense material provide structural evidence that barrier ability is not compromised in senile skin. The dermal/epidermal changes in aged skin are marked and have significant physiologic implications. The major change is a relatively flat dermal/epidermal junction resulting from the retraction of the epidermal papillae as well as the microprojections of basal cells into the dermis. This flattening results in a more fragile epidermal/dermal interface and, consequently, the epidermis is less resistant to shearing forces. Retraction of the epidermal downgrowths (preferential sites of the putative epidermal stem cell) may also explain the loss in proliferative capacity associated with the aged epidermis. The three-dimensional arrangements of collagen and elastic fibers showed marked alterations with age. Both fibrous components appear more compact because of a decrease in spaces between the fibers. Collagen bundles appear to unravel, and the individual elastic fibers show signs of elastosis. These changes may contribute to the loss of resilience that is one of the salient features of senile skin.

Morphology of aged skin.

Despite an overall thinning of the epidermis and focal areas of cytologic atypia, there was no morphologic evidence that the protective function of this tissue was compromised by age. The characteristic morphologic markers associated with the keratinization process were not altered either in appearance or in amounts. A well-formed stratum corneum was present, suggestive that barrier ability is not compromised in senile skin. Whereas alterations in the aged epidermis are slight, the dermal-epidermal changes are marked and have greater physiologic consequences. The major change is a relatively flat dermal-epidermal junction because of retraction of the epidermal papillae as well as the microprojections of basal cells into the dermis. This flattening results in a more fragile tissue less resistant to shearing forces. Retraction of the epidermal downgrowths may also explain the loss in proliferative capacity associated with the aged epidermis. The major alterations in the aged dermis concern the architecture of the collagen and elastin networks. Both fibrous components appear more compact because of a decrease in the voids or spaces between the fibers; the spaces resulted from a loss of ground substance. Collagen bundles appear to unravel, and the individual elastic fibers show signs of elastolysis. The net effect of these fibrous rearrangements and alterations is a dermis that is less stretchable, less resilient, more lax, and prone to wrinkling.