Lysyl hydroxylase 2-induced collagen cross-link switching promotes metastasis in head and neck squamous cell carcinomas

Abstract

Head and neck squamous cell carcinoma (HNSCC) is the 6th most common cancer worldwide and incidence rates are continuing to rise globally. HNSCC patient prognosis is closely related to the occurrence of tumor metastases, and collagen within the tumor microenvironment (TME) plays a key role in this process. Lysyl hydroxylase 2 (LH2), encoded by the Procollagen-Lysine,2-Oxoglutarate 5-Dioxygenase 2 ( PLOD2 ) gene, catalyzes hydroxylation of telopeptidyl lysine (Lys) residues of fibrillar collagens which then undergo subsequent modifications to form stable intermolecular cross-links that change the biomechanical properties (i.e. quality) of the TME. While LH2-catalyzed collagen modification has been implicated in driving tumor progression and metastasis in diverse cancers, little is known about its role in HNSCC progression. Thus, using gain- and loss-of-function studies, we examined the effects of LH2 expression levels on collagen cross-linking and cell behavior in vitro and in vivo using a tractable bioluminescent imaging-based orthotopic xenograft model. We found that LH2 overexpression dramatically increases HNSCC cell migratory and invasive abilities in vitro and that LH2-driven changes in collagen cross-linking robustly induces metastasis in vivo . Specifically, the amount of LH2-mediated collagen cross-links increased significantly with PLOD2 overexpression, without affecting the total quantity of collagen cross-links. Conversely, LH2 knockdown significantly blunted HNSCC cells invasive capacity in vitro and metastatic potential in vivo . Thus, regardless of the total “quantity” of collagen crosslinks, it is the “quality” of these cross-links that is the key driver of HNSCC tumor metastatic dissemination. These data implicate LH2 as a key regulator of HNSCC tumor invasion and metastasis by modulating collagen cross-link quality and suggest that therapeutic strategies targeting LH2-mediated collagen cross-linking in the TME may be effective in controlling tumor progression and improving disease outcomes.

Lysyl hydroxylase 2 mediated collagen post-translational modifications and functional outcomes

“…This is likely the reason why collagen enriched in the Hyl ald -derived cross-links accumulates without being readily degraded by proteolytic enzymes in fibrosis 28 , 56 , 57 and also in desmoplastic tumors such as pancreatic ductal adenocarcinoma 58 , lung cancer 29 , breast cancer 31 , 59 and oral cancer 30 . Such stiffened collagen matrix may not only form a shelter for cancer cells to protect them from immune cells and anti-cancer drugs but also serve as a means for cancer cells to attach, migrate and metastasize efficiently 41 , 60 , 61 . Second, based on one experiment, fibrillogenesis in LH2 KO collagen is also affected showing smaller fibril diameters compared to those of controls.…”

Activation of the CREB Coactivator CRTC2 by Aberrant Mitogen Signaling promotes oncogenic functions in HPV16 positive head and neck cancer

“…Lentiviruses (pLKO.1 lentivirus vector) were packaged as previously described [ 20 , [30] , [31] , [32] ]. Briefly, the pLKO.1-Scramble or pLKO.1-MAP3K1 shRNA plasmids (kind gift from Gary Johnson, UNC-Chapel Hill, Chapel Hill, NC) were co-transfected with VSV-G envelope plasmid and d8.2 gag/pol helper plasmids into Lenti X-293T cells (Takara #632180) seeded in 10 cm TC dishes in 7 mL of media.…”

A Fe2+-dependent self-inhibited state influences the druggability of human collagen lysyl hydroxylase (LH/PLOD) enzymes

“…Cancer cells take advantage of these “collagen highways” to migrate toward blood vessels that sustain metastatic progression ( Provenzano et al, 2006 ; Du et al, 2017b ; Gkretsi and Stylianopoulos, 2018 ). Over the last years, multiple studies correlated both hypoxia-dependent and independent overexpression and mislocalization of LH enzymes with increased propensity to metastatization in a wide variety of solid tumors, recognizing these enzymes as markers of adverse prognosis ( Chen et al, 2015 ; Chen et al, 2016 ; Pankova et al, 2016 ; Sato et al, 2021 ).…”