TABLE 1.

NOP receptor–expressing cell lines, cell derivation, NOP receptor expression levels, and cited references

NOP receptor expression was divided into the following ranges: 1–100 fmol/mg (+), 100–300 fmol/mg (++), 300–1000 fmol/mg (+++), >1 pmol/mg (++++). Cell derivation was based on documentation from American Type Culture Collection (www.atcc.org) or Sigma-Aldrich (www.sigmaaldrich.com)*.

Cell Line and Type of NOP Receptor Expression	Cell Derivation	NOP Receptor Expression Level	References
Cell Lines Endogenously Expressing NOP Receptors
BE(2)-C Human neuroblastoma	Neuroblast cells subcloned from SK-N-BE(2)	+	Homologous/heterologous NOP receptor desensitization; NOP receptor regulation of MOR desensitization and phosphorylation (Mandyam et al., 2000, 2002, 2003; Ozsoy et al., 2005; Thakker and Standifer, 2002a,b)
NG108-15 Mouse neuroblastoma/ Rat glioma	Somatic cell hybrid of N18TG2 and C6.BU.1	+	NOP receptor regulation of calcium channels; NOP receptor signaling cascades (Chan and Wong, 2000; Ma et al., 1997; Morikawa et al., 1998)
SH-SY5Y Human neuroblastoma	Subcloned from SK-N-SH	+	Homologous NOP receptor desensitization; Heterologous regulation by MOR and cannabinoid agonists; NOP receptor regulation of MOR; Intracellular signaling cascades (Cannarsa et al., 2012; Connor et al., 1996b; Donica et al., 2011; Mandyam et al., 2003; Thakker et al., 2007; Thakker and Standifer, 2002a,b)
SK-N-BE(2) Human neuroblastoma	Isolated from bone marrow biopsy of a 2-year-old male with neuroblastoma	+	Homologous NOP receptor internalization (Spampinato et al., 2001)
SK-N-SH Human neuroblastoma	Isolated from bone marrow biopsy of a 4-year-old female with neuroblastoma	+	Heterologous regulation of NOP receptor; NOP receptor signaling and homologous receptor regulation (Cheng et al., 1997; Zhao et al., 1998)
U937 Human monocyte	Isolated from adult male with histiocytic lymphoma	+	Peripheral blood mononuclear proliferation, Heterologous receptor desensitization of CXCR4 (Kaminsky and Rogers, 2011; Peluso et al., 2001)
Molt-4 Human T-lymphoblast	Isolated from adult male with acute lymphoblastic leukemia	+	Peripheral blood mononuclear proliferation (Peluso et al., 2001)
Recombinant Expression of NOP Receptors
CHO-K1 cells with hNOP receptor and Ecdysone-inducible hNOP receptor	Epithelial-like cells isolated from a biopsy of an adult Chinese hamster ovary	+, ++, ++++	Homologous NOP receptor desensitization and Down-regulation; Intracellular signaling cascades; Heterologous desensitization of NOP; Heterodimerization (Barnes et al., 2007; Bevan et al., 1998; Fukuda et al., 1998; Fukuda et al., 1997; Hashimoto et al., 2002; Hawes et al., 1998; Lou et al., 1997; McDonald et al., 2003; Okawa et al., 1999; Pan et al., 2002; Peluso et al., 2001; Spampinato and Baiula, 2006; Spampinato et al., 2002; Waits et al., 2004)
COS-7	African green monkey kidney fibroblast-like cells transformed with SV40	++++	G-protein coupling and NOP receptor expression (Chan and Wong, 2000; Chan et al., 1998; Ho et al., 2002)
HEK293 with hNOP receptor	Human embryonic kidney epithelial cells transformed with adenovirus 5 DNA	++++	Homologous NOP receptor desensitization and Down-regulation; Heterodimerization, heterologous desensitization (Corbani et al., 2004; Dautzenberg et al., 2001; Wang et al., 2005, 2006; Wu et al., 2003; Zhang et al., 2012a; Zhang et al., 1998)
tsA-201*	Human embryonic kidney 293 epithelial cells transformed with SV40	++++	Heterologous desensitization, and internalization, heterodimerization (Altier et al., 2006; Beedle et al., 2004; Evans et al., 2010)