Reader’s digest of the pathophysiology of bone metastases

The overlooked primary: bladder cancer metastases on dry bone. A study of the 20th century CAL Milano Cemetery Skeletal Collection

OBJECTIVE

The aim of this article is to provide additional documentation of bone metastases to help anthropologists recognize the condition and potentially suggest the diagnosis of bladder carcinoma in differential diagnosis.

MATERIALS AND METHODS

Thirteen individuals clinically diagnosed with bladder carcinoma from the 20^th century Milano Cemetery Skeletal Collection were macroscopically studied to document bone metastases in bladder cancer.

RESULTS

Bone metastases were found through macroscopic observation in three individuals or 23% of the study sample. Metastases were mostly of a mixed nature (45%), although both osteoblastic (13%) and osteolytic (9%) also occurred. In particular, mixed and osteoblastic metastases exhibited different distribution patterns, even when affecting the same bones. The vertebrae (24.7%), skull (12.9%), ribs (11.7%), proximal humeri (7.8%), pelvis (5.2%), proximal femora (2.6%), sacrum (1.3%) and sternum (1.3%) were the most commonly affected. Osteolytic lesions included coalescing superficial pits or lesions perforating the bone cortex. Proliferative lesions manifested as spongiosclerosis or periosteal new bone. Mixed metastases were osteolytic lesions exposing a thickened trabecular bone or coalescent porosity with reactive new bone.

CONCLUSIONS

Bladder carcinoma metastases were mostly mixed, exhibiting periosteal reactions, perforations of bone cortex, spongiosclerosis and coalescing porosity.

SIGNIFICANCE

Bladder carcinoma is rarely considered in the differential diagnosis of the primary organ. This study reports the macroscopic aspect of bone metastases in bladder carcinoma and may help anthropologists diagnose the condition in skeletons.

LIMITATIONS

Absence of evidence is not evidence of absence; some lesions may have been hidden from macroscopic observation and therefore missed.

FURTHER RESEARCH

Radiographic analysis and comparison with other neoplasms should provide additional details for the diagnosis of bladder cancer bone metastases.

Identification of Fibulin-1 as a Human Bone Marrow Stromal (HS-5) Cell-Derived Factor That Induces Human Prostate Cancer Cell Death

BACKGROUND

Previous studies showed that human bone marrow stromal HS-5 cells secreted unidentified factor(s) inducing PCa cell death. Herein, the HS-5-derived factor (HS-5 DF) was characterized and identified.

METHODS

Conditioned media from confluent HS-5 cells were collected and modified for biochemical characteristic testing of HS-5 DF. Cell survival was measured by apoptosis assay and live/dead assay. Fibulin-1 was identified from gel electrophoresis and mass spectrometry. The validation of Fibulin-1 as a HS-5 DF was done by immunoprecipitation (IP) and genetic knockdown by CRISPR/Cas9 system.

RESULTS

HS-5 DF was trypsin and heat sensitive, but pH stable. The tentative size of the factor fell between 30 kDa and 100 kDa. TGF-β1 treatment led to a suppression of HS-5 DF activity, a property consistent with bone metastasis in prostate cancer. Examination of TGF-β1 down regulated proteins led to identification of fibulin-1 as a candidate for the DF. IP of Fibulin-1 from HS-5 CM and CRISPR knockdown of Fibulin-1 showed a significant reduction of HS-5 CM-derived PCa cell death. These results strongly support a role for fibulin-1 in HS-5 bone marrow stromal cell induction of PCa cell death.

CONCLUSION

Our data indicate that Fibulin-1 functions as a HS-5 bone marrow stromal cell-derived factor inducing prostate cancer cell death. Prostate 77:729-742, 2017. © 2016 Wiley Periodicals, Inc.

Canine prostate cancer cell line (Probasco) produces osteoblastic metastases in vivo

BACKGROUND

In 2012, over 240,000 men were diagnosed with prostate cancer and over 28,000 died from the disease. Animal models of prostate cancer are vital to understanding its pathogenesis and developing therapeutics. Canine models in particular are useful due to their similarities to late-stage, castration-resistant human disease with osteoblastic bone metastases. This study established and characterized a novel canine prostate cancer cell line that will contribute to the understanding of prostate cancer pathogenesis.

METHODS

A novel cell line (Probasco) was derived from a mixed breed dog that had spontaneous prostate cancer. Cell proliferation and motility were analyzed in vitro. Tumor growth in vivo was studied by subcutaneous, intratibial, and intracardiac injection of Probasco cells into nude mice. Tumors were evaluated by bioluminescent imaging, Faxitron radiography, µCT, and histology. RT-PCR and genome-wide DNA copy number profiling were used to characterize the cell line.

RESULTS

The Probasco cells grew in vitro (over 75 passages) and were tumorigenic in nude mice. Probasco cells expressed high levels of BMP2, CDH1, MYOF, FOLH1, RUNX2, and SMAD5 modest CXCL12, SLUG, and BMP, and no PTHrP mRNA. Following intracardiac injection, Probasco cells metastasized primarily to the appendicular skeleton, and both intratibial and intracardiac injections produced osteoblastic tumors in bone. Comparative genomic hybridization demonstrated numerous DNA copy number aberrations throughout the genome, including large losses and gains in multiple chromosomes.

CONCLUSIONS

The Probasco prostate cancer cell line will be a valuable model to investigate the mechanisms of prostate cancer pathogenesis and osteoblastic bone metastases.