Hypothesis: The triad androgen receptor, zinc finger proteins and telomeres modulates the global gene expression pattern during prostate cancer progression

Upregulation of shelterin and CST genes and longer telomeres are associated with unfavorable prognostic characteristics in prostate cancer

INTRODUCTION

Search for new clinical biomarkers targets in prostate cancer (PC) is urgent. Telomeres might be one of these targets. Telomeres are the extremities of linear chromosomes, essential for genome stability and control of cell divisions. Telomere homeostasis relies on the proper functioning of shelterin and CST complexes. Telomeric dysfunction and abnormal expression of its components are reported in most cancers and are associated with PC. Despite this, there are only a few studies about the expression of the main telomere complexes and their relationship with PC progression. We aimed to evaluate the role of shelterin (POT1, TRF2, TPP1, TIN2, and RAP1) and CST (CTC1, STN1, and TEN1) genes and telomere length in the progression of PC.

METHODS

We evaluated genetic alterations of shelterin and CST by bioinformatics in samples of localized (n = 499) and metastatic castration-resistant PC (n = 444). We also analyzed the expression of the genes using TCGA (localized PC n = 497 and control n = 152) and experimental approaches, with surgical specimens (localized PC n = 81 and BPH n = 10) and metastatic cell lines (LNCaP, DU145, PC3 and PNT2 as control) by real-time PCR. Real-time PCR also determined the telomere length in the same experimental samples. All acquired data were associated with clinical parameters.

RESULTS

Genetic alterations are uncommon in PC, but POT1, TIN2, and TEN1 showed significantly more amplifications in the metastatic cancer. Except for CTC1 and TEN1, which are differentially expressed in localized PC samples, we did not detect an expression pattern relative to control and cell lines. Nevertheless, except for TEN1, the upregulation of all genes is associated with a worse prognosis in localized PC. We also found that increased telomere length is associated with disease aggressiveness in localized PC.

CONCLUSION

The upregulation of shelterin and CST genes creates an environment that favors telomere elongation, giving selective advantages for localized PC cells to progress to more aggressive stages of the disease.

Prostate Cancer and the Mevalonate Pathway

Antineoplastic therapies for prostate cancer (PCa) have traditionally centered around the androgen receptor (AR) pathway, which has demonstrated a significant role in oncogenesis. Nevertheless, it is becoming progressively apparent that therapeutic strategies must diversify their focus due to the emergence of resistance mechanisms that the tumor employs when subjected to monomolecular treatments. This review illustrates how the dysregulation of the lipid metabolic pathway constitutes a survival strategy adopted by tumors to evade eradication efforts. Integrating this aspect into oncological management could prove valuable in combating PCa.

Developmental transcriptional control of mitochondrial homeostasis is required for activity-dependent synaptic connectivity

During neuronal circuit formation, local control of axonal organelles ensures proper synaptic connectivity. Whether this process is genetically encoded is unclear and if so, its developmental regulatory mechanisms remain to be identified. We hypothesized that developmental transcription factors regulate critical parameters of organelle homeostasis that contribute to circuit wiring. We combined cell type-specific transcriptomics with a genetic screen to discover such factors. We identified Telomeric Zinc finger-Associated Protein (TZAP) as a temporal developmental regulator of neuronal mitochondrial homeostasis genes, including Pink1 . In Drosophila , loss of dTzap function during visual circuit development leads to loss of activity-dependent synaptic connectivity, that can be rescued by Pink1 expression. At the cellular level, loss of dTzap/TZAP leads to defects in mitochondrial morphology, attenuated calcium uptake and reduced synaptic vesicle release in fly and mammalian neurons. Our findings highlight developmental transcriptional regulation of mitochondrial homeostasis as a key factor in activity-dependent synaptic connectivity.

Identification of ISG15 and ZFP36 as novel hypoxia- and immune-related gene signatures contributing to a new perspective for the treatment of prostate cancer by bioinformatics and experimental verification

Background

Prostatic cancer (PCa) is one of the most common malignant tumors in men worldwide. Emerging evidence indicates significance of hypoxia and immunity in PCa invasion and metastasis. This study aimed to develop a hypoxia- and immune-related gene risk signature and explore the molecular mechanisms to formulate a better prognostic tool for PCa patients.

Methods

The hypoxia and immune scores of all PCa patients in The Cancer Genome Atlas (TCGA) dataset were calculated via the maximally selected rank statistics method and the ESTIMATE algorithm. From common genes identified overlapping hypoxia- and immune-related differentially expressed genes (DE-HRGs and DE-IRGs), a hypoxia- and immune-related gene risk signature was developed utilizing univariate and multivariate Cox regression analyses, and validated in the Memorial Sloan Kettering Cancer Centre (MSKCC) database. The immune cell infiltration level of PCa samples were evaluated with ssGSEA algorithm. Differential expression of prognostic genes was evidenced by immunohistochemistry and western blot (WB) in paired PCa samples. Expression levels of these genes and their variations under regular and hypoxic conditions were examined in cell lines. The functional effects of the prognostic gene on PCa cells were examined by wound healing and transwell assays.

Results

A hypoxia- and immune-related gene risk signature constructed by ISG15 and ZFP36 displays significant predictive potency, with higher risk score representing worse survival. A nomogram based on independent prognostic factors including the risk score and Gleason score exhibited excellent clinical value in the survival prediction of PCa. Infiltration levels of eosinophils, neutrophils, Tcm, Tem, TFH, Th1 cells, and Th17 cells were significantly lower in the high-risk group. Conversely, aDC, pDC, T helper cells, and Tregs were significantly higher. Additionally, the two prognostic genes were closely correlated with the tumor-infiltrating immune cell subset in PCa progression. RT-qPCR and WB presented higher and lower expression of ISG15 and ZFP36 in PCa cells, respectively. They were correspondingly increased and decreased in PCa cells under hypoxic conditions. Wound healing and transwell assays showed that over-expression of ISG15 promoted the migration and invasion of PCa cells.

Conclusion

Our study identified a novel hypoxia- and immune-related gene signature, contributing a new perspective to the treatment of PCa

Supplementary Information

The online version contains supplementary material available at 10.1186/s12967-022-03398-4.