Abstract 400: Coordinated loss of CD9 and IGSF8 expression on the prostate cancer cell surface contributes to metastasis and hormone responsiveness.
Bibliographic record
Abstract
Abstract The tetraspanin web is a complex multi-molecular cell structure that tethers cell surface signalling proteins (i.e. integrins) to their intermediate intracellular signalling partners (i.e. small GTPases) and anchors actin filaments. Loss of certain components of the web (CD9, CD82 or CD316) are associated with increased invasive and metastatic behaviors of prostate cancer (PCa) cells and here we demonstrate that two of these tetraspanin web components, CD9 and CD316, also play a role in regulating androgen signaling in PCa cells. Additionally, we utilized human prostate cancer tissue microarrays (TMAs) containing 261 prostate/PCa specimens of differing stages, grades and states of progression (including 60 castration resistant tumors [CRPCs]) to study the relationship between CD9 and CD316 expressions and progression to CRPC. Using androgen-dependent LNCaP cells as a model, we found that androgen deprivation (AD) suppressed expression of CD9 protein and mRNA without affecting CD316 expression. FACS analysis showed that the presence of CD9 on the cell surface was coordinately reduced by AD as was cell surface CD316 which was relocalized to the cytoplasm. This effect was reversed by addition of R1881. Knockdown of CD9 or CD316 in LNCaP cells using siRNA reduced expression of androgen receptor (AR) mRNA but increased expression of PSA, an AR target gene. CD9 or CD316 knockdown also increased LNCaP growth in fetal bovine serum (FBS) containing medium but not in charcoal-stripped FBS (CS-FBS) whereas dual-knockdown further increased growth in FBS as well as in CS-FBS. TMAs immunostained for CD9 or CD316 were assessed for correlation to clinicopathological parameters. For untreated, primary tumors, CD9 and CD316 expression were inversely correlated with Gleason scores (R2=0.9612). CD9 expression was diminished during progression to metastatic (p<0.0038, compared to non-metastatic) and further in CRPC (p<0.040, compared to metastatic non-treated) disease. Conversely, CD316 expression was increased in primary (non-metastatic) as well as in metastatic untreated disease but then reduced (p<0.046) during progression to metastatic CRPC. We propose that androgen deprivation (first line therapy for advanced PCa) may potentially trigger loss of both CD9 and IGSF8 expression on the cell surface that contributes to metastatic behaviors as well as to responsiveness to androgen ablation therapies. This work is supported by the Cancer Research Society (Canada). Citation Format: Na Li, Ladan Fazli, Estelle Li, Ralph Buttyan. Coordinated loss of CD9 and IGSF8 expression on the prostate cancer cell surface contributes to metastasis and hormone responsiveness. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 400. doi:10.1158/1538-7445.AM2013-400
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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 | 0.000 |
| Insufficient payload (model declined to judge) | 0.004 | 0.001 |
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".