Expression of E-cadherin and specific CXCR3 isoforms impact each other in prostate cancer

From biology to the clinic - exploring liver metastasis in prostate cancer

Liver metastases from prostate cancer are associated with an aggressive disease course and poor prognosis. Results from autopsy studies indicate a liver metastasis prevalence of up to 25% in patients with advanced prostate cancer. Population data estimate that ~3-10% of patients with metastatic castration-resistant prostate cancer harbour liver metastases at the baseline, rising to 20-30% in post-treatment cohorts, suggesting that selective pressure imposed by novel therapies might promote metastatic spread to the liver. Liver metastases are associated with more aggressive tumour biology than lung metastases. Molecular profiling of liver lesions showed an enrichment of low androgen receptor, neuroendocrine phenotypes and high genomic instability. Despite advancements in molecular imaging modalities such as prostate-specific membrane antigen PET-CT, and liquid biopsy markers such as circulating tumour DNA, early detection of liver metastases from prostate cancer remains challenging, as both approaches are hampered by false positive and false negative results, impeding the accurate identification of early liver lesions. Current therapeutic strategies showed limited efficacy in this patient population. Emerging targeted radionuclide therapies, metastasis-directed therapy, and novel systemic agents have shown preliminary activity against liver metastases, but require further validation. Treatment with various novel prostate cancer therapies might lead to an increase in the prevalence of liver metastasis, underscoring the urgent need for coordinated efforts across preclinical and clinical researchers to improve characterization, monitoring, and management of liver metastases from prostate cancer. Elucidating molecular drivers of liver tropism and interactions with the liver microenvironment might ultimately help to identify actionable targets to enhance survival in this high-risk patient group.

Patient with prostatic adenocarcinoma with plasmacytoid features and an aberrant immunohistochemical phenotype diagnosed by biopsy and a mini-review of plasmacytoid features in the genitourinary system: A case report

Prostate cancer is one of the most commonly diagnosed malignancies in men. Most of these tumors are adenocarcinomas. Plasmacytoid is a rare variant of adenocarcinoma described by previous studies in the genitourinary system and is characterized by the plasmacytoid appearance of tumor cells with abundant cytoplasm and abnormally placed hyperchromatic nuclei. However, to the best of our knowledge, plasmacytoid adenocarcinoma has rarely been described in the prostate. This report describes a new case of plasmacytoid adenocarcinoma of the prostate diagnosed by biopsy and summarizes the known literature on plasmacytoid features in the genitourinary system. A 62-year-old male patient presented to the hospital with urinary retention, hematuria, weakness and weight loss. The digital rectal examination revealed an irregular enlargement. Laboratory findings showed elevated levels of prostate specific antigen (PSA; 43.6 ng/ml). Transrectal ultrasound showed invasion of the right seminal vesicle. Prostate tumor core biopsies were collected and sent for diagnosis. Histological examination revealed a high-grade prostatic adenocarcinoma Gleason score of 5+5 (total score 10). The tumor cells had a plasmacytoid appearance with abundant cytoplasm and abnormally placed hyperchromatic nuclei. The immunohistochemical phenotype was characterized by abundant positivity for cytokeratin (CK)AE1/AE3 and PSA. By contrast, tumor cells were negative for p63, CK 34BE12 and GATA binding protein 3 (urothelial markers), synaptophysin (neuroendocrine marker). Tumor cells were also negative for E-cadherin, which is particularly indicative of CDH1 alterations. To the best of our knowledge, this is the first description of a plasmacytoid adenocarcinoma of the prostate diagnosed by biopsy, showing an irregular immunophenotype that may indicate somatic CDH1 alterations. The presentation of a novel rare variant of prostatic carcinoma that differs from other neoplasms of the genitourinary system may contribute to an improved understanding of this uncommonly found histological pattern that may also be mandatory due to the clinical and prognostic implications of this diagnosis.

Akt isoforms differentially provide for chemoresistance in prostate cancer

OBJECTIVE

Early prostate cancer micrometastatic foci undergo a mesenchymal to epithelial reverting transition, not only aiding seeding and colonization, but also rendering the tumor cells generally chemoresistant. We previously found that upregulated E-cadherin in the epithelial micrometastases activated canonical survival pathways, including PI3K-Akt, that protected the tumor cells from death; however, the extent of protection from blocking the pathway in its entirety was modest, because different isoforms may have alternately affected cell functioning. Here, we characterized Akt isoform expressions in primary and metastatic prostate cancers, as well as their individual contributions to chemoresistance.

METHODS

Akt isoforms and E-cadherin were manipulated with drugs, knocked down, and over expressed. Tumor cell killing was determined in vitro and in vivo. Overall survival was calculated from patient records and specimens.

RESULTS

Pan-Akt inhibition sensitized tumor cells to chemotherapy, and specific blockade of Akt1 or/and Akt2 caused cells to be more chemoresponsive. Overexpression of Akt3 induced apoptosis. A low dose of Akt1 or Akt2 inhibitor enabled standard chemotherapies to significantly eradicate metastatic prostate tumors in a mouse model, acting as chemosensitizers. In human specimens, we found Akt1 and Akt2 positively correlated, whereas Akt3 inversely correlated, with the overall survival of prostate cancer patients. Akt1high/Akt2high/Akt3low tumors had the worst outcomes.

CONCLUSIONS

E-cadherin-induced activation of Akt1/2 isoforms was the essential mechanism of chemoresistance, whereas Akt3 made cells more fragile. These findings emphasized the need to target Akt1/2, rather than pan-Akt, as a rational therapeutic approach.

Prostate cancer liver metastasis: Dormancy and resistance to therapy

Liver metastasis causes nearly half of death from solid tumors. Metastatic lesions, to the liver in particular, can become detectable years or decades after primary tumor removal, leaving an uncertain long-term prognosis in patients. Prostate cancer (PCa), a prominent metastatic dormant cancer, has the worst prognosis when found in the liver compared to other metastatic sites. These metastatic nodules display a therapy resistance in the liver pro-metastatic microenvironment; the resistance appears to be conferred by both dormancy and independent of dormancy when the nodules emerge. Within the review, the molecular underpinnings of how the liver aids and protects PCa cells seeding, colonization and resistance will be discussed.