Journal: Advanced Science

Article Title: VCP‐Regulated LMF2 Stabilizes the Cholesterol Biosynthesis Enzyme HMGCS1 to Drive Cancer Progression and Confer Capecitabine Resistance in Triple‐Negative Breast Cancer

doi: 10.1002/advs.78301

Figure Lengend Snippet: Please replace Figure 7 with the newly uploaded file "figure7.png" in the Attachments. In panel B, the y‐axis upper limit was adjusted so that two data points above 1.5 are fully displayed. All data, statistical analyses, and the figure legend remain completely unchanged.Clinical relevance of the VCP‐LMF2‐HMCGS1 axis in TNBC patient specimens. (A) Immunoblotting analyses of VCP, LMF2, and HMGCS1 protein levels in 14 paired TNBC and adjacent normal breast tissues. (B–D) Quantitative results of relative protein levels of VCP (B), LMF2 (C), and HMGCS1 (D) in TNBC and adjacent normal tissues ( n = 14). Data are presented as mean ± SD ( n = 14 pairs of clinical tissues). Statistical significance was determined by a paired two‐tailed Student's t ‐test. (E–G) Correlation analysis of protein levels between VCP and LMF2 (E), LMF2 and HMGCS1 (F), and VCP and HMGCS1 (G) in TNBC tissues ( n = 14). Correlations were analyzed by two‐tailed Pearson correlation analysis. (H) IHC staining of VCP, LMF2, and HMGCS1 expression in 25 TNBC samples. The representative images are shown. Top row, high protein expression; bottom row, low protein expression. Scale bars: 500 µm (left, low magnification) and 50 µm (right, high magnification). (I–K) Correlation analysis of IHC‐positive areas for VCP and LMF2 (I), LMF2 and HMGCS1 (J), and VCP and HMGCS1 (K) in 25 TNBC samples. Correlations were analyzed by two‐tailed Pearson correlation analysis. (L) The proposed working model. LMF2 is ubiquitinated, and this modification enables its recognition by NBR1, which subsequently targets it for lysosomal degradation. In TNBC, elevated VCP expression stabilizes LMF2 by counteracting this process. Similarly, HMGCS1 undergoes ubiquitination and is recognized by NDP52, leading to its autophagic degradation. Importantly, LMF2 exerts a protective effect on HMGCS1 by disrupting the HMGCS1–NDP52 interaction, thereby promoting HMGCS1 stability. The resulting enhancement of cholesterol biosynthesis fuels TNBC progression and confers resistance to capecitabine. This entire regulatory axis is effectively dismantled by the VCP inhibitor CB‑5083.

Article Snippet: Cells were treated with 2.5 μg/mL soluble cholesterol (#S4154, Selleck) for 24 h prior to functional assays following protocols adapted from prior studies [ ].

Techniques: Western Blot, Two Tailed Test, Analysis, Immunohistochemistry, Expressing, Modification, Ubiquitin Proteomics, Stability