The ALPP (placental alkaline phosphatase) knockout CAL-27 polyclonal cells are a CRISPR/Cas9-edited human oral squamous cell carcinoma cell population designed for loss-of-function studies of the ALPP gene. This polyclonal knockout product provides a heterogeneous pool of cells carrying targeted gene disruptions, enabling robust functional analyses without monoclonal selection. The disruption of ALPP abrogates expression of the GPI-anchored alkaline phosphatase, generating a versatile model to dissect ALPP-dependent signaling and cellular phenotypes in a tumor-relevant context.
The parental CAL-27 line is an adherent epithelial cell line derived from a metastatic site of human tongue squamous cell carcinoma. It is widely employed as a model for oral cancer invasion and metastasis, displaying characteristics of epithelial-mesenchymal transition (EMT) and responsiveness to extracellular matrix cues. CAL-27 cells provide a clinically relevant background for studying molecular drivers of head and neck cancer progression, making them ideal for investigating the role of ALPP in tumor biology.
ALPP encodes a glycosylphosphatidylinositol (GPI)-anchored ectoenzyme that hydrolyzes phosphomonoesters in the extracellular milieu, influencing phosphate metabolism and generating nucleoside precursors. In CAL-27 cells, ALPP localizes to lipid rafts where it interacts with caveolin-1 and integrin ??1, modulating focal adhesion dynamics. Its activity is upregulated by epidermal growth factor (EGF), steroid hormones, and the transcription factors NF-??B and AP-1. Functionally, ALPP-mediated dephosphorylation potentiates focal adhesion kinase (FAK) phosphorylation at Tyr397, leading to Src and ERK1/2 activation. This signaling axis suppresses E-cadherin expression via Snail-dependent transcriptional repression and promotes matrix metalloproteinase (MMP) secretion, thereby facilitating cell migration and invasion.
ALPP is frequently overexpressed in oral squamous cell carcinoma and correlates with advanced tumor stage and poor prognosis across multiple epithelial cancers. In CAL-27 cells, ALPP-dependent signaling drives a mesenchymal, invasive phenotype. Consequently, ALPP knockout in this line serves as a powerful platform to examine the specific contributions of alkaline phosphatase activity to focal adhesion turnover, EMT, and extracellular matrix remodeling. The polyclonal format retains the diversity of the parental population, minimizing clonal artifacts and enabling assessment of the overall functional impact of ALPP loss.
This ALPP knockout CAL-27 polyclonal cell pool supports diverse downstream applications. Researchers can employ it in Transwell migration and Matrigel invasion assays to quantify ALPP-dependent metastatic behavior, and monitor EMT marker changes (E-cadherin, vimentin, Snail) via Western blotting and immunofluorescence. Phospho-signaling studies (p-FAK Y397, p-ERK1/2) allow mapping of ALPP-driven pathways. The model enables drug sensitivity screening to identify compounds with differential effects on ALPP-null versus wild-type cells and can be used in xenograft metastasis models. Co-immunoprecipitation and proximity labeling may reveal novel ALPP interactors, while RNA-seq analysis delineates ALPP-dependent transcriptional networks. For further details on assay conditions and experimental support, please contact Ascent Research.
