Structure-based design of CDC42 effector interaction inhibitors for the treatment of cancer

CDC42 Inhibitors Alter Patterns of Vessel Arborization in Skin and Tumors in vivo

“…To more easily determine whether CDC42 inhibitors had direct effects on tumor vasculature, we used microtumor VMT devices where two vascular chambers had an intervening tumor chamber so that one could measure the effects of drugs after infusion on one side of the chamber versus the infusion of the other with vehicle (Fig 3A). ARN22089 disrupted the vasculature of the drug-treated but not the control side of the vasculature with a concomitant effect on tumor growth (Fig 3B), similar to the effects that were observed previously ( 40 ), with quantifiable effects on vessel length (Fig 3C). Next, we sought to examine whether ARN25062 and vemurafenib could also inhibit vessel growth in similar devices where tumor cells and blood vessels are spatially separated (Fig 3D).…”

“…When the tumors reached a volume of 150-200 mm 3 , we treated the mice with the indicated doses of the CDC42 inhibitor ARN22089, vemurafenib, or vehicle twice daily for two weeks (Figure 2A). We observed that ARN22089 inhibited the growth of tumors as effectively as vemurafenib despite the fact that the reported Kd for vemurafenib binding to its target Braf is >10-fold lower ( 49 ) than the IC50 of ARN22089 for CDC42 ( 40 ). To compare how ARN22089 and vemurafenib affected arborization of vessels in tumors, we: 1) sacrificed the mice after the two week treatment; 2) infused the mice with tomato lectin intravascularly; 3) cleared the tumors using our iDISCO protocol; 4) imaged these tumors with multiphoton microscopy to obtain three-dimensional image stacks; 5) converted 3D images to grayscale images; and 6) quantified vascular branching using neuTube (Figure 2B).…”

“…Previous work identified a class of CDC42 interaction inhibitors that could inhibit tumor growth in vivo (39, 40 ) and block angiogenesis in vascularized microtumors in vitro ( 40 ). To examine how CDC42 inhibitors modulate tumor angiogenesis in vivo , we implanted patient-derived xenografts into the flanks of NSG mice.…”

“…CDC42 inhibitors block both the interaction of RhoJ and CDC42 with their downstream effectors ( 40 ), and both RhoJ knockout mice and CDC42 inhibitor-treated mice had similar skin vessel arborization patterns. To examine whether CDC42 inhibitors modulate skin angiogenesis by inhibiting RhoJ, we treated wild-type and RhoJ knockout mice with the CDC42 inhibitor ARN22089 and used the same approach as described in Figure 4 to measure changes in vascularization.…”

“…Targeting CDC42 GTPases with small molecules has been problematic secondary to their globular structure and lack of readily apparent druggable pockets ( 37, 38 ). We recently used a structure-based drug design approach to discover a class of CDC42 GTPase inhibitors that block CDC42 downstream effector interactions ( 39, 40 ). These agents blocked S6 and ERK activation, inhibited angiogenesis in vascularized tumor organoids, and inhibited the growth of mouse and patient-derived tumors in vivo ( 39, 40 ).…”