Cell experiment:

A neurotoxic concentration of paraoxon (200 μM) is added to the granule cell cultures for the indicated time on day in vitro (DIV) 8. The following drugs are added to the granule cell cultures prior to or after paraoxon exposure on DIV 8: Ro-81-3220 (1 μM) is added 15 min prior to or 3 h after the addition of paraoxon. TPA (0.1 μM) is added 15 min prior to the addition of paraoxon[1].

Animal experiment:

Mice[4]The affects of long-term Ro 31-8220 administration over 4 to 6 weeks in MLP–/– heart failure mice are investigated. All mice are assessed for ventricular performance by echocardiography at the beginning of the study and 6 weeks later. Ro 31-8220 (or vehicle) is injected subcutaneously once per day at a dosage of 6 mg/kg/d[4].

Ro 31-8220 is a selective inhibitor of protein kinase C (PKC) with IC50 values of 5, 24, 14, 27, and 24 nM for PKC α, PKC βI, PKC βII, PKC γ and PKC ε, respectively [1].

PKC is a monomeric Ca2+- and phospholipid-dependent Ser/Thr protein kinases and plays an important role in growth factor-activated signaling and malignant transformation.

Ro 31-8220 is a selective inhibitor of PKC. Also, Ro 31-8220 increased growth factor-stimulated expression of c-Jun but inhibited MKP-1 and c-Fos expression. Ro-31-8220 strongly stimulated the stress-activated protein kinase JNK1 in a PKC-independent way [2]. In peripheral blood mononuclear cells, Ro 31-8220 inhibited the production of mitogen-induced interleukin (IL) -2 and IL-2-dependent T lymphoblast proliferation with IC50 values of 80 and 350 nM, respectively. Also, Ro 31-8220 (400 nM) inhibited IL-2Rα (CD25) expression by 27%, which suggested that Ro 31-8220 inhibited early and late T cell activation [3].

In rat adipocytes and L6 myotubes, RO 31-8220 activated c-Jun N-terminal kinase (JNK) and glycogen synthase (GS) and stimulated glucose incorporation into glycogen. While, RO 31-8220 inhibited the activity of extracellular response kinases 1 and 2 (ERK1/2) in a PKC-independent way [4].

References:
[1].  Wilkinson SE, Parker PJ, Nixon JS. Isoenzyme specificity of bisindolylmaleimides, selective inhibitors of protein kinase C. Biochem J, 1993, 294 ( Pt 2): 335-337.
[2].  Beltman J, McCormick F, Cook SJ. The selective protein kinase C inhibitor, Ro-31-8220, inhibits mitogen-activated protein kinase phosphatase-1 (MKP-1) expression, induces c-Jun expression, and activates Jun N-terminal kinase. J Biol Chem, 1996, 271(43): 27018-27024.
[3].  Geiselhart L, Conti DJ, Freed BM. RO 31-8220, a novel protein kinase C inhibitor, inhibits early and late T cell activation events. Transplantation, 1996, 61(11): 1637-1642.
[4].  Standaert ML, Bandyopadhyay G, Antwi EK, et al. RO 31-8220 activates c-Jun N-terminal kinase and glycogen synthase in rat adipocytes and L6 myotubes. Comparison to actions of insulin.