Prostate Cancer Treatment and Research / Cancer, Lipids, and Metabolism / Peroxisome Proliferator-activated Receptors · Journal article

Targeting the Fatty Acid Binding Protein 5–Specificity Protein 1 Axis Restores Enzalutamide Sensitivity by Suppressing Androgen Receptor/Androgen Receptor Splice Variant 7 Signaling: Implications for Prostate Cancer Therapy

World Journal of Oncology · September 5, 2026

Hypothesis-Generating Why this matters to you Expert discussion

Raises a question worth testing. It does not answer one.

AI Summary

This is a mechanistic investigation of a FABP5–Sp1–AR/AR-V7 regulatory axis in castration-resistant prostate cancer cells, supported by transcriptomic correlation in TCGA. Genetic and pharmacological manipulation of this axis in vitro restored enzalutamide sensitivity; however, no clinical validation, patient cohort testing, or animal model data are reported.

What was studied

In vitro mechanistic study with correlative transcriptomic analysis. 22RV1 castration-resistant prostate cancer cell line; TCGA Prostate Adenocarcinoma cohort for transcriptomic correlation. Intervention: FABP5 genetic ablation or overexpression; Sp1 pharmacological inhibition with mithramycin A. Compared with: Baseline/control cells; wild-type genotype.

Key findings

FABP5 is significantly upregulated in prostate tumors compared with normal tissue and increases with higher Gleason score FABP5 genetic ablation markedly reduced AR-V7 expression and restored enzalutamide sensitivity in 22RV1 cells FABP5 overexpression increased Sp1 protein levels

Safety

Sp1 pharmacological inhibition with mithramycin A coordinated downregulation of FABP5, AR, and AR-V7

Who this may help

This work proposes a therapeutic target and biomarker strategy but remains preclinical. Clinicians should await prospective validation in patient samples and clinical trials before considering FABP5 inhibition or Sp1 targeting for enzalutamide-resistant prostate cancer.

Plain-language summary

Mechanistic study in cell culture identifying a putative regulatory axis; lacks clinical validation, patient outcomes, or prospective testing needed to support therapeutic claims.

Study design

As stated by the source record.

MethodsTCGA-PRAD transcriptomic data were analyzed to examine FABP5, AR, and Sp1 expression patterns across tumors and normal tissue. In 22RV1 CRPC cells, FABP5 was genetically ablated or overexpressed, and Sp1 was pharmacologically inhibited with mithramycin A. Effects on AR-V7 expression, enzalutamide sensitivity, cell growth, and invasion were assessed.

DesignIn vitro mechanistic study with correlative transcriptomic analysis

Population22RV1 castration-resistant prostate cancer cell line; TCGA Prostate Adenocarcinoma cohort for transcriptomic correlation

InterventionFABP5 genetic ablation or overexpression; Sp1 pharmacological inhibition with mithramycin A

ComparatorBaseline/control cells; wild-type genotype

Clinical bottom line

Caveats

No quantitative effect sizes, p-values, or confidence intervals reported for primary findings
Single cell line model; generalizability to diverse CRPC phenotypes unknown
No animal model or patient-derived xenograft validation
Mithramycin A is a non-selective Sp1 inhibitor; specificity and off-target effects not addressed

Evidence assessment

Graded across the dimensions that decide whether you should act, each from what the source actually supports. There is no single score, and where a dimension was not assessed it says so.

Study design

limited

In vitro mechanistic work in single cell line; no clinical trial or patient cohort study.

Directness

limited

Cell culture and transcriptomic correlations; no direct patient outcome or treatment response data.

Consistency

insufficient

Single cell model tested; no independent replication or validation cohort reported.

Risk of bias

moderate

Transcriptomic analysis observational; functional validation limited to one CRPC cell line.

Sample adequacy

limited

22RV1 cells only; TCGA-PRAD used for correlation but no prospective patient validation.

What is missing. This record has no reported figures. That is a gap in the analysis, not a judgement about the study.

Source abstract

Background: Castration-resistant prostate cancer (CRPC) remains a major clinical challenge driven by persistent androgen receptor (AR) signaling and constitutively active splice variants such as androgen receptor splice variant 7 (AR-V7), which confer resistance to therapies including enzalutamide. Although metabolic reprogramming contributes to disease progression, the integration of metabolic and transcriptional regulators sustaining therapeutic resistance remains incompletely understood. Methods: We integrated clinical transcriptomic analysis of The Cancer Genome Atlas Prostate Adenocarcinoma (TCGA-PRAD) cohort with mechanistic and functional validation in 22RV1 CRPC cells to investigate the role of the fatty acid binding protein 5–specificity protein 1 (FABP5–Sp1) regulatory axis. Results: Transcriptomic analysis revealed that FABP5 is significantly upregulated in prostate tumors compared with normal tissue and increases with higher Gleason score. In contrast, AR and Sp1 exhibited heterogeneous expression patterns. Mechanistically, genetic ablation of FABP5 markedly reduced AR-V7 expression and restored sensitivity to enzalutamide, leading to suppression of AR signaling. Conversely, FABP5 overexpression increased Sp1 protein levels. Pharmacological inhibition of Sp1 using mithramycin A resulted in coordinated downregulation of FABP5, AR, and AR-V7, along with suppression of peroxisome proliferator-activated receptor gamma (PPARγ) signaling and downstream vascular endothelial growth factor A (VEGFA) expression. Functionally, Sp1 inhibition significantly reduced anchorage-independent growth and invasion. Conclusion: These findings define a FABP5–Sp1–AR/AR-V7 transcriptional–metabolic axis driving enzalutamide resistance in CRPC. Targeting FABP5 restores therapeutic sensitivity and represents a promising biomarker and therapeutic strategy in advanced prostate cancer.

Follow from this

Taken from the source record, never inferred. Follow any of these and new work involving them reaches your briefing.

Faisal F. AlamriSaud A AbdulsamadAbdulghani A NaeemProstate Cancer Treatment and ResearchAhmaed BaasharCancer, Lipids, and MetabolismAhmed A. AldarmahiGang HePeroxisome Proliferator-activated Receptors