Ki: 231 nmol/L

APTSTAT3-9R-9R is a STAT3 inhibitor.

STAT3 has been reported to promote the proliferation, survival, metastasis, immune escape, as well as drug resistance of cancer cells, making it a promising target for various diseases. However, though multiple STAT3 inhibitors and its regulatory or effector pathway elements have been identified, bioactive agents are limited.

In vitro: Previous study showed that APTSTAT3-9R bound to STAT3 with high specificity and affinity. Moreover, the addition of a cell-penetrating motif to the peptide to yield APTSTAT3-9R enabled uptake by murine B16F1 melanoma cells. In addition, treatment of various types of cancer cells with APTSTAT3-9R was able to inhibit STAT3 phosphorylation and reduce expression of STAT targets, such as Bcl-xL, cyclin D1, and survivin. As a result, APTSTAT3-9R could suppress the viability and proliferation of cancer cells [1].

In vivo: In a previous animal in vivo study, a human lung carcinoma xenograft model was prepared by subcutaneous implantation of A549 cancer cells. After tumors had reached a volume of approximately 50 mm3 after two weeks, APTSTAT3-9R was intratumorally injected every other day for a total of four injections. Results showed that the tumor burden was significantly reduced in the APTSTAT3-9R–treated group when compared with that in the control group; however, there was little difference in tumor size between APTscr-9R and control groups [1].

Clinical trial: Up to now, ALTSTADT3-9R is still in the preclinical development stage.

Reference:
[1] Kim D,Lee IH,Kim S,Choi M,Kim H,Ahn S,Saw PE,Jeon H,Lee Y,Jon S.  A specific STAT3-binding peptide exerts antiproliferative effects and antitumor activity by inhibiting STAT3 phosphorylation and signaling. Cancer Res.2014 Apr 15;74(8):2144-51.