Probes for INS

Telomerase consists of at least two essential elements, an RNA component hTR or TERC that contains the template for telomere DNA addition, and a catalytic reverse transcriptase (TERT). While expression of TERT has been considered the key rate limiting component for telomerase activity, increasing evidence suggests an important role for the regulation of TERC in telomere maintenance and perhaps other functions in human cancer. By using three orthogonal methods including RNAseq, RT-qPCR, and an analytically validated chromogenic RNA in situ hybridization assay, we report consistent overexpression of TERC in prostate cancer. This overexpression occurs at the precursor stage (e.g. high grade prostatic intraepithelial neoplasia or PIN), and persists throughout all stages of disease progression. Levels of TERC correlate with levels of MYC (a known driver of prostate cancer) in clinical samples and we also show the following: forced reductions of MYC result in decreased TERC levels in 8 cancer cell lines (prostate, lung, breast, and colorectal); forced overexpression of MYC in PCa cell lines, and in the mouse prostate, results in increased TERC levels; human TERC promoter activity is decreased after MYC silencing; and MYC occupies the TERC locus as assessed by chromatin immunoprecipitation (ChIP). Finally, we show that knockdown of TERC by siRNA results in reduced proliferation of prostate cancer cell lines. These studies indicate that TERC is consistently overexpressed in all stages of prostatic adenocarcinoma, and its expression is regulated by MYC. These findings nominate TERC as a novel prostate cancer biomarker and therapeutic target.

Abstract

BACKGROUND:

Loss or mutation of PTEN alleles at 10q23 in combination with 8q24 amplification (encompassing MYC) are common findings in aggressive, human prostate cancer. Our group recently developed a transgenic murine model of prostate cancer involving prostate-specific Pten deletion and forced expression of MYC under the control of the Hoxb13 promoter. MYC overexpression cooperated with Pten loss to recapitulate lethal, human prostate cancer.

METHOD:

We now report on the generation of two mouse prostate cancer cell lines, BMPC1 and BMPC2, derived from a lymph node, and liver metastasis, respectively.

RESULTS:

Both cell lines demonstrate a phenotype consistent with adenocarcinoma and grew under standard tissue culture conditions. Androgen receptor (AR) protein expression is minimal (BMPC1) or absent (BMPC2) consistent with AR loss observed in the BMPC mouse model of invasive adenocarcinoma. Growth in media containing charcoal-stripped serum resulted in an increase in AR mRNA in BMPC1 cells with no effect on protein expression, unless androgens were added, in which case AR protein was stabilized, and showed nuclear localization. AR expression in BMPC2 cells was not effected by growth media or treatment with androgens. Treatment with an anti-androgen/castration or androgen supplemented media did not affect in vitro or in vivo growth of either cell line, irrespective of nuclear AR detection.

DISCUSSION:

These cell lines are a novel model of androgen-insensitive prostatic adenocarcinoma driven by MYC over-expression and Pten loss.

Normal brain function depends on the interaction between highly specialized neurons that operate within anatomically and functionally distinct brain regions. Neuronal specification is driven by transcriptional programs that are established during early neuronal development and remain in place in the adult brain. The fidelity of neuronal specification depends on the robustness of the transcriptional program that supports the neuron type-specific gene expression patterns. Here we show that polycomb repressive complex 2 (PRC2), which supports neuron specification during differentiation, contributes to the suppression of a transcriptional program that is detrimental to adult neuron function and survival. We show that PRC2 deficiency in striatal neurons leads to the de-repression of selected, predominantly bivalent PRC2 target genes that are dominated by self-regulating transcription factors normally suppressed in these neurons. The transcriptional changes in PRC2-deficient neurons lead to progressive and fatal neurodegeneration in mice. Our results point to a key role of PRC2 in protecting neurons against degeneration.

The prognostic role of MYC has been well documented in non-central nervous system diffuse large B-cell lymphoma; however, it remains controversial in central nervous system diffuse large B-cell lymphoma. To investigate the prognostic value of MYC, we analyzed the MYC protein expression by immunohistochemistry, mRNA expression by RNA in situ hybridization, and gene status by fluorescence in situ hybridization in 74 cases of central nervous system diffuse large B-cell lymphoma. Moreover, we examined the correlation between MYC translocation, mRNA expression, and protein expression. The mean percentage of MYC immunopositive cells was 49%. Using a 44% cutoff value, 49 (66%) cases showed MYC protein overexpression. The result of mRNA in situ hybridization using the RNA scope technology was obtained using the H-scoring system; the median value was 34.2. Using the cutoff value of 63.5, 16 (22%) cases showed MYC mRNA overexpression. MYC gene rearrangement was detected in five out of 68 (7%) cases. MYC translocation showed no statistically significant correlation with mRNA expression; however, all MYC translocation-positive cases showed MYC protein overexpression, with a higher mean percentage of MYC protein expression than that of translocation-negative cases (78 vs 48%, P=0.001). The level of MYC mRNA expression was moderately correlated with the level of MYC protein expression (P<0.001). The mean percentage of MYC protein expression in the high MYC mRNA group was higher than that in the low MYC mRNA group (70 vs 47%, P<0.001). A univariate analysis showed that age over 60 years, Eastern Cooperative Oncology Group (ECOG) performance status ≥2 and MYC protein overexpression were significantly associated with an increased risk of death. MYC translocation and MYC mRNA expression had no prognostic significance. On multivariate analysis, MYC protein overexpression and ECOG score retained prognostic significance.

Abstract

Objectives

Recent commercialization of methods for in situ hybridization using Z-pair probe/branched DNA amplification has led to increasing adoption of this technology for interrogating RNA expression in formalin-fixed, paraffin-embedded (FFPE) tissues. Current practice for FFPE block storage is to maintain them at room temperature, often for many years.

Methods

To examine the effects of block storage time on FFPE tissues using a number of RNA in situ probes with the Advanced Cellular Diagnostic’s RNAscope assay.

Results

We report marked reductions in signals after 5 years and significant reductions often after 1 year. Furthermore, storing unstained slides cut from recent cases (<1 year old) at –20°C can preserve hybridization signals significantly better than storing the blocks at room temperature and cutting the slides fresh when needed.

Conclusions

We submit that the standard practice of storing FFPE tissue blocks at room temperature should be reevaluated to better preserve RNA for in situ hybridization.