Lactylation-mediated IGF2BPs/rmrp axis and effects on bladder cancer progression through the regulation of cancer cells and cancer-associated fibroblasts.

Abstract

e16576 Background: Bladder cancer (BCa) is a common malignancy with high incidence and mortality. Epigenetic modifications, particularly N6-methyladenosine (m6A) RNA, are critical in BCa progression. IGF2BPs, as m6A readers, stabilize target RNAs and regulate glycolysis, promoting BCa malignancy. Methods: Single-cell sequencing identified elevated IGF2BPs expression in BCa epithelial cells. In vitro experiments assessed the effects of IGF2BPs knockdown on BCa cell proliferation, migration, invasion, and organoid growth. Mechanistic studies investigated the IGF2BPs-RMRP-PDHX axis, glycolysis regulation, lactate production, and TME modulation. Urinary exosomal m6A-RMRP was evaluated as a biomarker. Results: IGF2BPs knockdown suppressed BCa cell proliferation, migration, invasion, and organoid growth. Mechanistically, IGF2BPs stabilized m6A-modified RMRP, which inhibited PDHX, suppressed PDH activity, and promoted glycolysis. Lactate and exosomal RMRP secreted by BCa cells enhanced the TME by promoting cGAS lactylation in CAFs and suppressing the cGAS-STING pathway. This established an immunosuppressive TME, further driving BCa progression. Clinically, urinary exosomal m6A-RMRP correlated with tumor stage, grade, and lymph node metastasis, showing superior diagnostic performance compared to NMP22 testing. Combining m6A-RMRP and NMP22 improved sensitivity and specificity. Conclusions: The IGF2BPs-RMRP-PDHX axis drives BCa progression by regulating glycolysis. Lactate and exosomal RMRP modulate the TME and exacerbate malignancy. Urinary exosomal m6A-RMRP is a promising biomarker for BCa diagnosis and prognosis, offering new insights into its molecular mechanisms and clinical management. Correlation between expression of urinary exosomal m6A-RMRP and clinicopathological characteristics in BCa patients. Characteristics Case Urinary exosomal m6A-RMRP Χ 2 P value Low High All cases 150 75 75 Gender  Male 117 60(51.28%) 57(48.72%) 0.350 0.554  Female 33 15(45.45%) 18(54.55%) Age (years)  ≤65 68 36(52.94%) 32(47.06%) 0.430 0.512  ＞65 82 39(47.56%) 43(52.44%) Tumor size (cm)  ≤3 104 53(50.96%) 51(49.04%) 0.125 0.723  ＞3 46 22(47.83%) 24(52.17%) Tumor stage (T)  Ta-T1 117 67(57.26%) 50(42.74%) 8.552 0.003 **  T2-T4 33 8(24.24%) 25(75.76%) Lymph node Metastasis  Negative 128 70(54.69%) 58(45.31%) 7.670 0.006 **  Positive 22 5(22.73%) 17(77.27%) Grade  Low 30 10(33.33%) 20(66.67%) 4.167 0.041 *  Middle-High 120 65(54.17%) 55(45.83%) Tumor number  Single 111 55(49.55%) 56(50.45%) 0.035 0.852  Multiple 39 20(51.28%) 19(48.72%) Frequency  Primary 115 58(50.43%) 57(49.57%)  Recurrence 35 17(48.57%) 18(51.43%) 0.037 0.847 NMP22  Negative 83 44(53.01%) 39(46.99%) 0.674 0.412  Positive 67 31(46.27%) 36(53.73%) *P < 0.05, **P < 0.01.