The secreted matrix protein mindin increases prostate tumor progression and tumor-bone crosstalk via ERK 1/2 regulation

Prostate Cancer: Pathophysiology, Pathology and Therapy

Prostate cancer (PCa) is a major health care challenge in the developed world, being the most common type of cancer in men in the USA [...].

The multifaceted roles of the chemokines CCL2 and CXCL12 in osteophilic metastatic cancers

Breast and prostate cancers have a great propensity to metastasize to long bones. The development of bone metastases is life-threatening, incurable, and drastically reduces patients' quality of life. The chemokines CCL2 and CXCL12 and their respective receptors, CCR2 and CXCR4, are central instigators involved in all stages leading to cancer cell dissemination and secondary tumor formation in distant target organs. They orchestrate tumor cell survival, growth and migration, tumor invasion and angiogenesis, and the formation of micrometastases in the bone marrow. The bone niche is of particular importance in metastasis formation, as it expresses high levels of CCL2 and CXCL12, which attract tumor cells and contribute to malignancy. The limited number of available effective treatment strategies highlights the need to better understand the pathophysiology of bone metastases and reduce the skeletal tumor burden in patients diagnosed with metastatic bone disease. This review focuses on the involvement of the CCL2/CCR2 and CXCL12/CXCR4 chemokine axes in the formation and development of bone metastases, as well as on therapeutic perspectives aimed at targeting these chemokine-receptor pairs.

Downregulation of Snail by DUSP1 Impairs Cell Migration and Invasion through the Inactivation of JNK and ERK and Is Useful as a Predictive Factor in the Prognosis of Prostate Cancer

Dual specificity phosphatase 1 (DUSP1) is crucial in prostate cancer (PC), since its expression is downregulated in advanced carcinomas. Here, we investigated DUSP1 effects on the expression of mesenchymal marker Snail, cell migration and invasion, analyzing the underlying mechanisms mediated by mitogen-activated protein kinases (MAPKs) inhibition. To this purpose, we used different PC cells overexpressing or lacking DUSP1 or incubated with MAPKs inhibitors. Moreover, we addressed the correlation of DUSP1 expression with Snail and activated MAPKs levels in samples from patients diagnosed with benign hyperplasia or prostate carcinoma, studying its implication in tumor prognosis and survival. We found that DUSP1 downregulates Snail expression and impairs migration and invasion in PC cells. Similar results were obtained following the inhibition of c-Jun N-terminal kinase (JNK) and extracellular-signal-regulated kinase (ERK). In clinical samples, we evidenced an inverse correlation between DUSP1 expression and Snail levels, which are further associated with JNK and ERK activation. Consequently, the pattern DUSP1_high/activated JNK_low/activated ERK_low/Snail_low is associated with an overall extended survival of PC patients. In summary, the ratio between DUSP1 and Snail expression, with additional JNK and ERK activity measurement, may serve as a potential biomarker to predict the clinical outcome of PC patients. Furthermore, DUSP1 induction or inhibition of JNK and ERK pathways could be useful to treat PC.

MINDIN Exerts Protumorigenic Actions on Primary Prostate Tumors via Downregulation of the Scaffold Protein NHERF-1

Advanced prostate cancer preferential metastasis to bone is associated with osteomimicry. MINDIN is a secreted matrix protein upregulated in prostate tumors that overexpresses bone-related genes during prostate cancer progression. Na+/H+ exchanger regulatory factor (NHERF-1) is a scaffold protein that has been involved both in tumor regulation and osteogenesis. We hypothesize that NHERF-1 modulation is a mechanism used by MINDIN to promote prostate cancer progression. We analyzed the expression of NHERF-1 and MINDIN in human prostate samples and in a premetastatic prostate cancer mouse model, based on the implantation of prostate adenocarcinoma TRAMP-C1 (transgenic adenocarcinoma of the mouse prostate) cells in immunocompetent C57BL/6 mice. The relationship between NHERF-1 and MINDIN and their effects on cell proliferation, migration, survival and osteomimicry were evaluated. Upregulation of MINDIN and downregulation of NHERF-1 expression were observed both in human prostate cancer samples and in the TRAMP-C1 model. MINDIN silencing restored NHERF-1 expression to control levels in the mouse model. Stimulation with MINDIN reduced NHERF-1 expression and triggered its mobilization from the plasma membrane to the cytoplasm in TRAMP-C1 cells. MINDIN-dependent downregulation of NHERF-1 promoted tumor cell migration and proliferation without affecting osteomimicry and adhesion. We propose that MINDIN downregulates NHERF-1 expression leading to promotion of processes involved in prostate cancer progression.