Landscape of chromosome number changes in prostate cancer progression

Additional activation of the AR gene may be involved in the development of the castration resistance phenotype in prostate cancer

INTRODUCTION

Several studies have already shown that changes in the AR gene may be associated with a more aggressive disease phenotype and even castration-resistant prostate cancer. Thus, we investigated cytogenetic and molecular alterations linked to AR.

MATERIALS AND METHODS

To evaluate AR methylation, we performed a cytogenetic-molecular analysis using fluorescence in situ hybridization that uses specific probes for the AR gene (Xq11.12) and the X chromosome centromere. For AR activity, we performed a qualitative analysis of human androgen receptor activity. To analyze the expression of AR in PC3 and LNCaP cell lines, we used qPCR assays.

RESULTS

In the qPCR assay, we found downregulation of AR in the PC3 cell line compared with the LNCaP. We found the presence of X chromosome polysomy in PC-3 and LNCaP cell lines by FISH assay. In the HUMARA-Q assay, we found two X chromosomes/cell and the activity of both AR in the PC-3 cell line. In LNCaP cells, we found two X chromosomes/cell and methylation of only one AR.

CONCLUSION

Castration-resistant prostate cancer phenotype represents a significant challenge in the setting of urological management. The X chromosomes and AR-linked alterations may contribute to a better understanding of the disease. However, further studies should be performed in an attempt to elucidate as much as possible the role of AR in the castration-resistant prostate cancer phenotype.

Systematic Elucidation of the Aneuploidy Landscape and Identification of Aneuploidy Driver Genes in Prostate Cancer

Aneuploidy is widely identified as a remarkable feature of malignancy genomes. Increasing evidences suggested aneuploidy was involved in the progression and metastasis of prostate cancer (PCa). Nevertheless, no comprehensive analysis was conducted in PCa about the effects of aneuploidy on different omics and, especially, about the driver genes of aneuploidy. Here, we validated the association of aneuploidy with the progression and prognosis of PCa and performed a systematic analysis in mutation profile, methylation profile, and gene expression profile, which detailed the molecular process aneuploidy implicated. By multi-omics analysis, we managed to identify 11 potential aneuploidy driver genes (GSTM2, HAAO, C2orf88, CYP27A1, FAXDC2, HFE, C8orf88, GSTP1, EFS, HIF3A, and WFDC2), all of which were related to the development and metastasis of PCa. Meanwhile, we also found aneuploidy and its driver genes were correlated with the immune microenvironment of PCa. Our findings could shed light on the tumorigenesis of PCa and provide a better understanding of the development and metastasis of PCa; additionally, the driver genes could be promising and actionable therapeutic targets pointing to aneuploidy.

Modelling the Functions of Polo-Like Kinases in Mice and Their Applications as Cancer Targets with a Special Focus on Ovarian Cancer

Polo-like kinases (PLKs) belong to a five-membered family of highly conserved serine/threonine kinases (PLK1-5) that play differentiated and essential roles as key mitotic kinases and cell cycle regulators and with this in proliferation and cellular growth. Besides, evidence is accumulating for complex and vital non-mitotic functions of PLKs. Dysregulation of PLKs is widely associated with tumorigenesis and by this, PLKs have gained increasing significance as attractive targets in cancer with diagnostic, prognostic and therapeutic potential. PLK1 has proved to have strong clinical relevance as it was found to be over-expressed in different cancer types and linked to poor patient prognosis. Targeting the diverse functions of PLKs (tumor suppressor, oncogenic) are currently at the center of numerous investigations in particular with the inhibition of PLK1 and PLK4, respectively in multiple cancer trials. Functions of PLKs and the effects of their inhibition have been extensively studied in cancer cell culture models but information is rare on how these drugs affect benign tissues and organs. As a step further towards clinical application as cancer targets, mouse models therefore play a central role. Modelling PLK function in animal models, e.g., by gene disruption or by treatment with small molecule PLK inhibitors offers promising possibilities to unveil the biological significance of PLKs in cancer maintenance and progression and give important information on PLKs' applicability as cancer targets. In this review we aim at summarizing the approaches of modelling PLK function in mice so far with a special glimpse on the significance of PLKs in ovarian cancer and of orthotopic cancer models used in this fatal malignancy.

The emerging links between chromosomal instability (CIN), metastasis, inflammation and tumour immunity

Many cancers possess an incorrect number of chromosomes, a state described as aneuploidy. Aneuploidy is often caused by Chromosomal Instability (CIN), a process of continuous chromosome mis-segregation. CIN is believed to endow tumours with enhanced evolutionary capabilities due to increased intratumour heterogeneity, and facilitating adaptive resistance to therapies. Recently, however, additional consequences and associations with CIN have been revealed, prompting the need to understand this universal hallmark of cancer in a multifaceted context. This review is focused on the investigation of possible links between CIN, metastasis and the host immune system in cancer development and treatment. We specifically focus on these links since most cancer deaths are due to the consequences of metastasis, and immunotherapy is a rapidly expanding novel avenue of cancer therapy.

FGF-2 is a driving force for chromosomal instability and a stromal factor associated with adverse clinico-pathological features in prostate cancer

BACKGROUND

There is mounting evidence to suggest that stromal cells play an integral role in the progression of prostate cancer (PCa). One of the most frequently altered growth factors in PCa is fibroblast growth factor-2 (FGF-2). It has previously been proposed that early stages of PCa are characterized by a primarily exogenous, that is, stromal cell-derived FGF-2 production, whereas advanced tumors rely more on an autocrine FGF-2 production. Prostate cancer progression is characterized by an increase of genomic instability including aneuploidy and structural chromosomal alterations. Herein, we address 2 problems that have not been comprehensively answered. First, we ask whether exogenous FGF-2 can directly drive genomic instability to promote PCa progression. Second, we investigate whether and to what extent stromal FGF-2 expression is maintained in advanced PCa and whether this influences tumor progression and patient prognosis.

METHODS

In vitro experiments to investigate the role of FGF-2 in numerical and structural chromosomal instability were performed using immunofluorescence microscopy, fluorescence in situ hybridization and single cell electrophoresis. A human patient-derived xenograft mouse model recapitulating osteoblastic PCa bone metastasis was used for in vivo validation experiments. The prognostic role of stromal FGF-2 expression was analyzed using immunohistochemical staining of a tissue microarray with primary tumor specimens from 162 predominantly high-risk patients with PCa.

RESULTS

Our results show that FGF-2 not only rapidly induces mitotic defects and numerical chromosomal imbalances but also an enhanced DNA breakage to promote chromosomal instability. Using the patient-derived xenograft model, we show that a deregulation of the FGF axis results in an increase of mitotic aberrations as well as DNA damage checkpoint activation in vivo. The FGFR inhibitor dovitinib was found to reduce numerical chromosomal instability as well as DNA breakage, thus underscoring the relevance of the FGF axis in promoting genomic instability. An overexpression of tumor cell-associated FGF-2 was detected in 52 of 162 patients (32.1%), whereas a stromal overexpression was found in 27 of 165 patients (16%). Remarkably, a strong stromal FGF-2 expression was associated with a significantly higher clinical stage and higher biochemical recurrence rate. Patients with strong stromal FGF-2 expression also had a significantly worse biochemical recurrence-free survival.

CONCLUSIONS

Our results underscore that exogenous FGF-2 can shape PCa cell genomes and that stromal FGF-2 expression is detectable in a sizeable proportion of advanced PCa where it is associated with adverse clinico-pathological features. Our results highlight the impact of the tumor stroma on malignant progression and provide a rationale for a further exploration of components of the tumor stroma as therapeutic targets in PCa.

Phosphohistone-H3 Proliferation Index Is Superior to Mitotic Index and MIB-1 Expression as a Predictor of Recurrence in Human Meningiomas

OBJECTIVES

This study investigated the prognostic value of the phosphohistone-H3 (PHH3) proliferation index (PI) in human meningiomas and compared the reliability with the conventional mitotic index and MIB-1 biomarker.

METHODS

Proliferative activity was determined in 160 patients by standardized immunohistochemistry on tissue microarrays and related to recurrence.

RESULTS

All three proliferation assessment methods were significantly associated with World Health Organization grade. The optimal cutoff values for recurrence prediction were 3% for the MIB-1 PI and 0.5% for the PHH3 PI. Increased PHH3 PI was significantly associated with recurrence-free survival in univariate Cox proportional hazards regression analysis (P = .011) and remained an independent predictor in multivariate analysis (P = .005). Mitotic index and MIB-1 PI did not reach statistical significance.

CONCLUSIONS

PHH3 immunostaining allowed for the easiest, fastest, and most objective assessment of proliferation and proved to be the most accurate and reliable method for predicting recurrence in patients resected for meningiomas.

Better see to better agree: phosphohistone H3 increases interobserver agreement in mitotic count for meningioma grading and imposes new specific thresholds

BACKGROUND

Mitotic count on hematoxylin and eosin (H&E)-stained slides is a crucial diagnostic criterion in meningioma grading. However, mitosis assessment on H&E slides can be impaired by technical factors and by pathologist's experience. Phosphohistone H3 (PHH3) serine-10 is a mitosis-specific antibody that has proven to facilitate mitotic count in various tumors.

METHODS

A series of 70 meningiomas (15 grade I, 40 grade II, 15 grade III) was used to validate PHH3 intra- and interobserver reproducibility and to identify PHH3-specific mitotic thresholds. Four pathologists with different experience in neuropathology counted mitoses on both H&E- and PHH3-stained slides.

RESULTS

H&E and PHH3 mitotic rates were highly correlated (Pearson's r = 0.92, P < .0001). PHH3 mitotic counts had both a good mean interobserver correlation (R(m) = 0.83) and a good intraclass correlation (0.78), higher than H&E mitotic indices (R(m) = 0.77, intraclass correlation = 0.71). After further stratification of meningiomas according to World Health Organization grade, PHH3 performed better in terms of interobserver concordance (Kendall's W = 0.761) compared with H&E (Kendall's W = 0.697). Referring to the same meningioma groups identified by World Health Organization grade as the gold standard, the volume under the receiver operator characteristic surface was 0.91, indicating a very good diagnostic ability of PHH3 scores in discriminating the 3 meningioma groups. The 2 optimal PHH3-specific cutoff values were 6.61 and 22.02.

CONCLUSION

PHH3 staining is a useful diagnostic complementary tool to standard H&E mitotic count, optimizing intra- and interobserver reproducibility. PHH3-specific mitotic thresholds should be adopted to avoid overgrading of meningioma when ancillary methods are employed.

Comparative diagnostic and prognostic performances of the hematoxylin-eosin and phospho-histone H3 mitotic count and Ki-67 index in adrenocortical carcinoma

Mitotic count on hematoxylin and eosin slides is a fundamental morphological criterion in the diagnosis and grading of adrenocortical carcinoma in any scoring system employed. Moreover, it is the unique term strongly associated with patient's prognosis. Phospho-histone H3 is a mitosis-specific antibody, which was already proven to facilitate mitotic count in melanoma and other tumors. Therefore, a study was designed to assess the diagnostic and prognostic role of phospho-histone H3 in 52 adrenocortical carcinomas, comparing manual and computerized count to standard manual hematoxylin- and eosin-based method and Ki-67 index. Manual hematoxylin and eosin and phospho-histone H3 mitotic counts were highly correlated (r=0.9077, P<0.0001), better than computer-assisted phospho-histone H3 evaluations, and had an excellent inter-observer reproducibility at Bland-Altman analysis. Three of 15 cases having <5 mitotic figures per 50 high-power fields by standard count on hematoxylin and eosin gained the mitotic figure point of Weiss Score after a manual count on phospho-histone H3 slides. Traditional mitotic count confirmed to be a strong predictor of overall survival (P=0.0043), better than phospho-histone H3-based evaluation (P=0.051), but not as strong as the Ki-67 index (P<0.0001). The latter further segregated adrenocortical carcinomas into three prognostic groups, stratifying cases by low (<20%), intermediate (20-50%), and high (>50%) Ki-67 values. We conclude that (a) phospho-histone H3 staining is a useful diagnostic complementary tool to standard hematoxylin and eosin mitotic count, enabling optimal mitotic figure evaluation (including atypical mitotic figures) even in adrenocortical carcinomas with a low mitotic index and with a very high reproducibility; (b) Ki-67 proved to be the best prognostic indicator of overall survival, being superior to the mitotic index, irrespective of the method (standard on hematoxylin and eosin or phospho-histone H3-based) used to count mitotic figures.

Prognostic significance of phospho-histone H3 in prostate carcinoma

PURPOSE

Prostate cancer is the second most common cancer in men and the sixth most common cause of death from cancer in men worldwide. Currently, a sufficient pathological distinction between patients requiring further treatment and those for which active surveillance remains an option is still lacking, which leads to the problem of overtreatment. Cell proliferation is routinely assessed by detecting Ki-67 antigen. While Ki-67 is expressed throughout the interphase of proliferating cells, phosphorylation of the chromatin constituent histone H3 occurs only during the late G2 phase and mitosis thus providing a more strict assessment of the mitotic activity. We undertook this study to test whether expression of the recently introduced proliferation marker phospho-histone H3 (pHH3) in prostate carcinoma tissue sections exhibits prognostic significance in comparison with Ki-67.

METHODS

Protein expression of pHH3 and Ki-67 was assessed on TMA consisting of paraffin-embedded tissue from men that had undergone radical prostatectomy. The analysis included triplicate tissue cores of a total of 339 tumor foci. Immunohistochemical staining of pHH3 and Ki-67 was performed and analyzed using Definiens imaging software.

RESULTS

Prostate cancer tissue exhibited a significantly higher frequency of pHH3-positive cells compared to benign prostate tissue. pHH3 expression was significantly correlated with Ki-67 expression. Furthermore, statistical analysis revealed positive correlation between pHH3 expression and PSA levels at diagnosis and in addition negatively correlated with overall survival. In contrast to Ki-67 staining, pHH3 expression did not correlate with Gleason grade.

CONCLUSION

Our data point to a conceivable role of pHH3 as prognostic biomarker in prostate carcinoma.