Cracking it - successful mRNA extraction for digital gene expression analysis from decalcified, formalin-fixed and paraffin-embedded bone tissue

CEACAM6 Promotes Lung Metastasis via Enhancing Proliferation, Migration and Suppressing Apoptosis of Prostate Cancer Cells

BACKGROUND/AIM

Metastatic prostate cancer (mPCa) results in high morbidity and mortality. Visceral metastases in particular are associated with a shortened survival. Our aim was to unravel the molecular mechanisms that underly pulmonary spread in mPCa.

MATERIALS AND METHODS

We performed a comprehensive transcriptomic analysis of PCa lung metastases, followed by functional validation of candidate genes. Digital gene expression analysis utilizing the NanoString technology was performed on mRNA extracted from formalin-fixed, paraffin-embedded (FFPE) tissue from PCa lung metastases. The gene expression data from primary PCa and PCa lung metastases were compared, and several publicly available bioinformatic analysis tools were used to annotate and validate the data.

RESULTS

In PCa lung metastases, 234 genes were considerably up-regulated, and 78 genes were significantly down-regulated when compared to primary PCa. Carcinoembryonic antigen-related cell adhesion molecule 6 (CEACAM6) was identified as suitable candidate gene for further functional validation. CEACAM6 as a cell adhesion molecule has been implicated in promoting metastatic disease in several solid tumors, such as colorectal or gastric cancer. We showed that siRNA knockdown of CEACAM6 in PC-3 and LNCaP cells resulted in decreased cell viability and migration as well as enhanced apoptosis. Comprehensive transcriptomic analyses identified several genes of interest that might promote metastatic spread to the lung.

CONCLUSION

Functional validation revealed that CEACAM6 might play an important role in fostering metastatic spread to the lung of PCa patients via enhancing proliferation, migration and suppressing apoptosis in PC-3 and LNCaP cells. CEACAM6 might pose an attractive therapeutic target to prevent metastatic disease.

SIUrO best practice recommendations to optimize BRCA 1/2 gene testing from DNA extracted from bone biopsy in mCRPC patients (BRCA Optimal Bone Biopsy Procedure: BOP)

The main guidelines and recommendations for the implementation of the BRCA1/2 somatic test do not focus on the clinical application of predictive testing on bone metastases, a frequent condition in metastatic prostate cancer, by analyzing the critical issues encountered by laboratory practice. Our goal is to produce a document (protocol) deriving from a multidisciplinary team approach to obtain high quality nucleic acids from biopsy of bone metastases. This document aims to compose an operational check-list of three phases: the pre-analytical phase concerns tumor cellularity, tissue processing, sample preservation (blood/FFPE), fixation and staining, but above all the decalcification process, the most critical phase because of its key role in allowing the extraction of somatic DNA with a good yield and high quality. The analytical phase involves the preparation of the libraries that can be analyzed in various NGS genetic sequencing platforms and with various bioinformatics software for the interpretation of sequence variants. Finally, the post-analytical phase that allows to report the variants of the BRCA1/2 genes in a clear and usable way to the clinician who will use these data to manage cancer therapy with PARP Inhibitors.

A Quality Analysis of Bony Specimens for Optimal Ethylenediaminetetraacetic Acid (EDTA) Decalcification

Introduction: Weak acids, such as etheylenediaminetetraacetic acid (EDTA), chelate calcium ions from the surface of tissues, decalcifying slowly but preserving molecular structures for ancillary testing. There is a need for optimization of EDTA protocols for specimen decalcification. We studied the effects of EDTA on different types of bony specimens for quality assurance. Methods: Specimens included: proximal femur curettage (0.7 g), fibula shave (1 mm thick, 0.5 g), tibia shave (2 mm thick, 0.9 g), and femur 11-gauge core biopsies. Curettage and shave specimens were placed in formalin then EDTA (Newcomersupply, Middleton, WI, USA) with continuous stirring. Specimens were removed at 24, 48, 72, 96, and 120 hours. Core biopsies were processed in EDTA with heat at 4, 8, 12, and 16 hours. X-ray imaging (Kubtec Xpert 40, Stratford, CT, USA) was obtained. Histological processing was attempted and H&E slides compared to radiologic imaging. Results: Fibula and tibia sections showed appropriate radiolucency at 120 hours and 7 days, respectively. Curettage specimens showed radiolucency of medullary bone at 48 hours. Curettage and fibula sections showed quality histology at 96 hours and 120 hours, respectively. Quality tibia sections were obtained at 7 days, requiring one hour of additional block surface decalcification with 1% HCL solution. Medullary and cortical core biopsies showed quality histology at 12 and 16 hours with heat, respectively. Conclusion: Imaging can determine appropriate decalcification of bony specimens. Medullary bone undergoes more rapid decalcification in EDTA than cortical bone. EDTA decalcification is best used for curettage and core biopsy specimens.