Prostate cancer is the second most common cancer in men, for which there are no reliable biomarkers or targeted therapies. Here we demonstrate that elevated levels of Δ133TP53β isoform characterize prostate cancers with immune cell infiltration, particularly T cells and CD163+ macrophages. These cancers are associated with shorter progression-free survival, Gleason scores ≥ 7, and an immunosuppressive environment defined by a higher proportion of PD-1, PD-L1 and colony-stimulating factor 1 receptor (CSF1R) positive cells. Consistent with this, RNA-seq of tumours showed enrichment for pathways associated with immune signalling and cell migration. We further show a role for hypoxia and wild-type p53 in upregulating Δ133TP53 levels. Finally, AUC analysis showed that Δ133TP53β expression level alone predicted aggressive disease with 88% accuracy. Our data identify Δ133TP53β as a highly accurate prognostic factor for aggressive prostate cancer.

∆122p53 mice (a model of ∆133p53 isoform) are tumour-prone, have extensive inflammation and elevated serum IL-6. To investigate the role of IL-6 we crossed ∆122p53 mice with IL-6 null mice. Here we show that loss of IL-6 reduced JAK-STAT signalling, tumour incidence and metastasis. We also show that ∆122p53 activates RhoA-ROCK signalling leading to tumour cell invasion, which is IL-6-dependent and can be reduced by inhibition of JAK-STAT and RhoA-ROCK pathways. Similarly, we show that Δ133p53 activates these pathways, resulting in invasive and migratory phenotypes in colorectal cancer cells. Gene expression analysis of colorectal tumours showed enrichment of GPCR signalling associated with ∆133TP53 mRNA. Patients with elevated ∆133TP53 mRNA levels had a shorter disease-free survival. Our results suggest that ∆133p53 promotes tumour invasion by activation of the JAK-STAT and RhoA-ROCK pathways, and that patients whose tumours have high ∆133TP53 may benefit from therapies targeting these pathways.

BackgroundMortality from colorectal cancer is mainly due to metastatic liver disease. Improved understanding of the molecular events underlying metastasis is crucial for the development of new methods for early detection and treatment of colorectal cancer. Loss of chromosome 8p is frequently seen in colorectal cancer and implicated in later stage disease and metastasis, although a single metastasis suppressor gene has yet to be identified. We therefore examined 8p for genes involved in colorectal cancer progression.MethodsLoss of heterozygosity analyses were used to map genetic loss in colorectal liver metastases. Candidate genes in the region of loss were investigated in clinical samples from 44 patients, including 6 with matched colon normal, colon tumour and liver metastasis. We investigated gene disruption at the level of DNA, mRNA and protein using a combination of mutation, semi-quantitative real-time PCR, western blotting and immunohistochemical analyses.ResultsWe mapped a 2 Mb region of 8p21-22 with loss of heterozygosity in 73% of samples; 8/11 liver metastasis samples had loss which was not present in the corresponding matched primary colon tumour. 13 candidate genes were identified for further analysis. Both up and down-regulation of 8p21-22 gene expression was associated with metastasis. ADAMDEC1 mRNA and protein expression decreased during both tumourigenesis and tumour progression. Increased STC1 and LOXL2 mRNA expression occurred during tumourigenesis. Liver metastases with low DcR1/TNFRSF10C mRNA expression were more likely to present with extrahepatic metastases (p = 0.005). A novel germline truncating mutation of DR5/TNFRSF10B was identified, and DR4/TNFRSF10A SNP rs4872077 was associated with the development of liver metastases (p = 0.02).ConclusionOur data confirm that genes on 8p21-22 are dysregulated during colorectal cancer progression. Interestingly, however, instead of harbouring a single candidate colorectal metastasis suppressor 8p21-22 appears to be a hot-spot for tumour progression, encoding at least 13 genes with a putative role in carcinoma development. Thus, we propose that this region of 8p comprises a metastatic susceptibility locus involved in tumour progression whose disruption increases metastatic potential.

A number of naturally occurring isoforms of the tumour suppressor protein p53 have been discovered, which appear to have differing roles in tumour prevention or promotion. We are investigating the tumour-promoting activities of the Δ133p53 isoform using our mouse model of Δ133p53 (Δ122p53). Here, we report that tumours from Δ122p53 homozygous mice show evidence of invasion and metastasis and that Δ122p53 promotes migration though a 3-dimensional collagen matrix. We also show that Δ122p53 and Δ133p53 promote cell migration in scratch wound and Transwell assays, similar to the 'gain-of-function' phenotypes seen with mutant p53. Using the well-defined B16 mouse melanoma metastatic model, we show that Δ122p53 leads to faster generation of lung metastases. The increased migratory phenotypes are dependent on secreted factors, including the cytokine interleukin-6 and the chemokine CCL2. We propose that Δ122p53 (and Δ133p53) acts in a similar manner to 'gain-of-function' mutant p53 proteins to promote migration, invasion and metastasis, which may contribute to poor survival in patients with Δ133p53-expressing tumours.

Lithium chloride (LiCl) exhibits significant therapeutic potential as a treatment for osteoarthritis. Hedgehog signaling is activated in osteoarthritis, where it promotes chondrocyte hypertrophy and cartilage matrix catabolism. Hedgehog signaling requires the primary cilium such that maintenance of this compartment is essential for pathway activity. Here we report that LiCl (50 mM) inhibits Hedgehog signaling in bovine articular chondrocytes such that the induction of GLI1 and PTCH1 expression is reduced ​ by 71 and 55%, respectively. Pathway inhibition is associated with a 97% increase in primary cilia length from 2.09 ± 0.7 μm in untreated cells to 4.06 ± 0.9 μm in LiCl-treated cells. We show that cilia elongation disrupts trafficking within the axoneme with a 38% reduction in Arl13b ciliary localization at the distal region of the cilium, consistent with the role of Arl13b in modulating Hedgehog signaling. In addition, we demonstrate similar increases in cilia length in human chondrocytes in vitro and after administration of dietary lithium to Wistar rats in vivo. Our data provide new insights into the effects of LiCl on chondrocyte primary cilia and Hedgehog signaling and shows for the first time that pharmaceutical targeting of the primary cilium may have therapeutic benefits in the treatment of osteoarthritis.

Prognostic markers for glioblastoma multiforme (GBM) are important for patient management. Recent advances have identified prognostic markers for GBMs that use telomerase or the alternative lengthening of telomeres (ALT) mechanism for telomere maintenance. Approximately 40% of GBMs have no defined telomere maintenance mechanism (NDTMM), with a mixed survival for affected individuals. This study examined genetic variants in the cyclin-dependent kinase inhibitor 2A (CDKN2A) gene that encodes the p16INK4a and p14ARF tumor suppressors, and the isocitrate dehydrogenase 1 (IDH1) gene as potential markers of survival for 40 individuals with NDTMM GBMs (telomerase negative and ALT negative by standard assays), 50 individuals with telomerase, and 17 individuals with ALT positive tumors. The analysis of CDKN2A showed NDTMM GBMs had an increased minor allele frequency for the C500G (rs11515) polymorphism compared to those with telomerase and ALT positive GBMs (p = 0.002). Patients with the G500 allele had reduced survival that was independent of age, extent of surgery, and treatment. In the NDTMM group G500 allele carriers had increased loss of CDKN2A gene dosage compared to C500 homozygotes. An analysis of IDH1 mutations showed the R132H mutation was associated with ALT positive tumors, and was largely absent in NDTMM and telomerase positive tumors. In the ALT positive tumors cohort, IDH1 mutations were associated with a younger age for the affected individual. In conclusion, the G500 CDKN2A allele was associated with NDTMM GBMs from older individuals with poorer survival. Mutations in IDH1 were not associated with NDTMM GBMs, and instead were a marker for ALT positive tumors in younger individuals.

The literature concerning the subcellular location of Y-box binding protein 1 (YB-1), its abundance in normal and cancer tissues, and its prognostic significance is replete with inconsistencies. An explanation for this could be due in part to the use of different antibodies in immunohistochemical and immunofluorescent labeling of cells and tissues. The inconsistencies could also be due to poor resolution of immunohistochemical data. We analyzed two cohorts of breast tumours for both abundance and subcellular location of YB-1 using three different antibodies; two targeting N-terminal epitopes (AB- a and AB- b) and another (AB- c) targeting a C-terminal epitope. We also investigated stress-induced nuclear translocation of YB-1 in cell culture. We report that both AB- a and AB- c detected increased YB-1 in the cytoplasm of high-grade breast cancers, and in those lacking estrogen and progesterone receptors; however the amount of YB-1 detected by AB- a in these cancers is significantly greater than that detected by AB- c. We confirm our previously published findings that AB- b is also detecting hnRNP A1, and cannot therefore be used to reliably detect YB-1 by immunohistochemistry. We also report that AB- a detected nuclear YB-1 in some tumour tissues and stress treated cells, whereas AB- c did not. To understand this, cancer cell lines were analyzed using native gel electrophoresis, which revealed that the antibodies detect different complexes in which YB-1 is a component. Our data suggest that different YB-1 antibodies show different staining patterns that are determined by the accessibility of epitopes, and this depends on the nature of the YB-1 complexes. It is important therefore to standardize the protocols if YB-1 is to be used reproducibly as a prognostic guide for different cancers.

Paired box (PAX ) developmental genes are frequently expressed in cancers and confer survival advantages on cancer cells. We have previously found that PAX genes are deregulated in glioma. We have now investigated the expression of PAX genes in glioma and their role in telomere maintenance. The mRNA level of PAX8 showed a positive correlation with telomerase activity in glioma biopsies (r 2 = 0.75, P < 0.001) and in established glioma cell lines (r 2 = 0.97, P = 0.0025). We found that PAX8 is able to coordinately transactivate the promoter for both the telomerase catalytic subunit (hTERT) and the telomerase RNA component (hTR) genes. By electrophoretic mobility shift assay, quantitative PCR, and a telomerase activity assay, we show that PAX8 binds directly to the hTERT and hTR promoters, up-regulating hTERT and hTR mRNA, as well as telomerase activity. Additionally, PAX8 small interfering RNA down-regulated hTERT and hTR. Collectively, these results show that PAX8 may have a role in telomerase regulation. [Cancer Res 2008; 68(14):5724-32]