Targeting collagen XVIII improves the efficiency of ErbB inhibitors in breast cancer models
Raman Devarajan, … , Taina Pihlajaniemi, Ritva Heljasvaara
Raman Devarajan, … , Taina Pihlajaniemi, Ritva Heljasvaara
Published July 27, 2023
Citation Information: J Clin Invest. 2023;133(18):e159181. https://doi.org/10.1172/JCI159181.
View: Text | PDF | Corrigendum
Research Article Oncology

Targeting collagen XVIII improves the efficiency of ErbB inhibitors in breast cancer models

Abstract

The tumor extracellular matrix (ECM) critically regulates cancer progression and treatment response. Expression of the basement membrane component collagen XVIII (ColXVIII) is induced in solid tumors, but its involvement in tumorigenesis has remained elusive. We show here that ColXVIII was markedly upregulated in human breast cancer (BC) and was closely associated with a poor prognosis in high-grade BCs. We discovered a role for ColXVIII as a modulator of epidermal growth factor receptor tyrosine kinase (ErbB) signaling and show that it forms a complex with ErbB1 and -2 (also known as EGFR and human epidermal growth factor receptor 2 [HER2]) and α6-integrin to promote cancer cell proliferation in a pathway involving its N-terminal portion and the MAPK/ERK1/2 and PI3K/AKT cascades. Studies using Col18a1 mouse models crossed with the mouse mammary tumor virus–polyoma virus middle T antigen (MMTV-PyMT) mammary carcinogenesis model showed that ColXVIII promoted BC growth and metastasis in a tumor cell–autonomous manner. Moreover, the number of mammary cancer stem cells was significantly reduced in the MMTV-PyMT and human cell models upon ColXVIII inhibition. Finally, ablation of ColXVIII substantially improved the efficacy of ErbB-targeting therapies in both preclinical models. In summary, ColXVIII was found to sustain the stemness properties of BC cells and tumor progression and metastasis through ErbB signaling, suggesting that targeting ColXVIII in the tumor milieu may have important therapeutic potential.

Authors

Raman Devarajan, Valerio Izzi, Hellevi Peltoketo, Gunilla Rask, Saila Kauppila, Marja-Riitta Väisänen, Heli Ruotsalainen, Guillermo Martínez-Nieto, Sanna-Maria Karppinen, Timo Väisänen, Inderjeet Kaur, Jussi Koivunen, Takako Sasaki, Robert Winqvist, Aki Manninen, Fredrik Wärnberg, Malin Sund, Taina Pihlajaniemi, Ritva Heljasvaara

×

Figure 7

Interactions between ColXVIII, ErbBs, and integrins and analyses of ErbB signaling.

Options: View larger image (or click on image) Download as PowerPoint
Interactions between ColXVIII, ErbBs, and integrins and analyses of ErbB...
(A) Representative images of immunostaining for ColXVIII, EGFR, and α6-integrin (ITGA6) in JIMT-1 and MDA-MB-231 cells (n ≥3). (B–D) In situ PLA in JIMT-1 and MDA-MB-231 cells. (B) Evidence of proximity (distance < 40 nm) for ColXVIII (mAb DB144-N2) and EGFR (mAb 52894) and for ColXVIII (mAb DB144-N2) and α6-integrin (primary Ab [pAb] 97760) is indicated by the presence of red dots. PLAs without pAbs served as the negative controls. Scale bars: 50 μm (A); 20 μm (B). (C and D) Quantitation of PLA counts for ColXVIII and EGFR (C) and ColXVIII and α6-integrin (D) (n = 3 biological replicates; n = 20 cells per sample). (E and F) Co-IP of ColXVIII (mouse mAB DB144-N2), EGFR (rabbit mAb 52894), and α6-integrin (rabbit pAb 97760) in HER2+ JIMT-1 (E) cells and in triple-negative MDA-MB-231 (F) cells. Protein complexes were detected in Western blot (WB) with ColXVIII (rabbit pAb QH48.18) and HER2 (rabbit mAb 4290) Abs (n ≥ 5). Goat anti–rabbit (Rb) IgG– and goat anti–mouse (Mo) IgG–coated magnetic bead controls are shown. (G) Representative immunoblots of EGFR and downstream signaling mediators in scrambled and ColXVIII-KD JIMT-1 and MDA-MB-231 cell lysates. In MDA-MB-231 cell lysates, the results for p-EGFR and EGFR along with ColXVIII were derived from another biological replicate. (H) Quantitation of ColXVIII, and EGFR, ERK, and AKT phosphorylation in JIMT-1 and MDA-MB-231 cell lysates (n = 3 biological replicates). **P < 0.01 and ***P < 0.001, by 2-tailed Student’s t test (H). Error bars indicate the SD.