Abstract 3791: TRPV6 calcium channel peptide antagonists as novel antimyeloma and antiresorptive agents
Bibliographic record
Abstract
Abstract Background: Multiple myeloma and its associated bone disease are generally incurable. Hence, better therapies are needed, ideally targeting biomolecules implicated in the aberrant biology of the disease. Overexpression of transient receptor potential cation channel TRPV6, a highly selective calcium channel has been observed in breast, colon, thyroid, ovary and prostate cancer tissues, and in several tumour cell lines. TRPV6 expression has also been seen in osteoclasts, however its role in bone metabolism remains unclear. The reciprocal interaction between osteoclasts and myeloma cells is pivotal to the generation of bone lesions that characterize myeloma. While myeloma cells secrete factors promoting osteoclast activity, osteoclasts in turn are known to induce myeloma cell growth and survival. The TRPV6 peptide antagonist SOR-C13 is currently in phase I clinical trials as an anti-cancer therapy for advanced cancers. We investigated the expression and potential therapeutic significance of TRPV6 in human osteoclasts and myeloma cells using shrew venom derived peptide antagonists. Methods: High affinity TRPV6 peptide antagonists SOR-C13 and SOR-C27 derived from the C-terminus of venom from the short-tailed shrew, Blarina brevicauda were used. Human primary osteoclasts were generated in vitro from human bone marrow (BM) aspirates; characterized by Hoechst-phalloidin staining, Tartrate resistant acid phosphatase (TRAP) staining, TRAP enzyme activity and Cathepsin K expression. CD138 positive myeloma cells were isolated from patient bone marrow specimens by EasySep immunomagnetic separation, or examined in tissue microarrays of patient BM core biopsies. TRPV6 expression in primary human osteoclasts, myeloma cell lines and myeloma patient BM microarray was checked by qPCR, immunohistochemistry or immunoblotting. Anti-resorptive potential of SOR peptides using human osteoclasts was evaluated in Osteoassay plates that mimic bone, and myeloma cell growth inhibition was determined by prestoblue cell viability assays. Results: We found strong expression of TRPV6 protein in human myeloma cells and osteoclasts by immunohistochemical staining on myeloma patient bone marrow sections. Human osteoclasts generated in vitro and CD138 positive myeloma patient bone marrow plasma cells were found to express TRPV6. We saw dose-dependent inhibition of osteoclast activity in vitro by SOR-C13 and SOR-C27, including markedly reduced osteoclast formation, decreased TRAP activity and reduced osteoassay surface resorption. TRPV6 peptide antagonists were also found to inhibit the growth of human myeloma cell lines U266 and KMM-1. Conclusion: Anti-myeloma and anti-osteoclast activity of human TRPV6 antagonist peptides was seen in the current study. Taken together, our findings suggest a novel therapeutic approach for multiple myeloma involving TRPV6 inhibition to target both myeloma cells and osteoclasts. Citation Format: Alli Murugesan, Philippe Tremblay, Ming Han, Bithika Ray, Tyler Lutes, Tony Reiman. TRPV6 calcium channel peptide antagonists as novel antimyeloma and antiresorptive agents. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 3791.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.001 |
| Insufficient payload (model declined to judge) | 0.005 | 0.002 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".