Antibodies against insulin-like growth factor (IGF) type 1 receptor have shown meaningful but transient tumor responses in patients with rhabdomyosarcoma (RMS). The SRC family member YES has been shown to mediate IGF type 1 receptor (IGF-1R) antibody acquired resistance, and cotargeting IGF-1R and YES resulted in sustained responses in murine RMS models. We conducted a phase I trial of the anti-IGF-1R antibody ganitumab combined with dasatinib, a multi-kinase inhibitor targeting YES, in patients with RMS (NCT03041701).
Patients with relapsed/refractory alveolar or embryonal RMS and measurable disease were eligible. All patients received ganitumab 18 mg/kg intravenously every 2 weeks. Dasatinib dose was 60 mg/m2/dose (max 100 mg) oral once daily [dose level (DL)1] or 60 mg/m2/dose (max 70 mg) twice daily (DL2). A 3+3 dose escalation design was used, and maximum tolerated dose (MTD) was determined on the basis of cycle 1 dose-limiting toxicities (DLT).
Thirteen eligible patients, median age 18 years (range 8-29) enrolled. Median number of prior systemic therapies was 3; all had received prior radiation. Of 11 toxicity-evaluable patients, 1/6 had a DLT at DL1 (diarrhea) and 2/5 had a DLT at DL2 (pneumonitis, hematuria) confirming DL1 as MTD. Of nine response-evaluable patients, one had a confirmed partial response for four cycles, and one had stable disease for six cycles. Genomic studies from cell-free DNA correlated with disease response.
The combination of dasatinib 60 mg/m2/dose daily and ganitumab 18 mg/kg every 2 weeks was safe and tolerable. This combination had a disease control rate of 22% at 5 months.

Ponatinib is a multi-target tyrosine kinase inhibitor that targets ABL, SRC, FGFR, and so on. It was designed to overcome the resistance of BCR-ABL mutation to imatinib, especially the gatekeeper mutation ABLT315I. The molecular mechanism by which ponatinib overcomes mutations of BCR-ABL and some other targets has been explained, but little information is known about the characteristics of ponatinib binding to SRC. Here, we showed that ponatinib inhibited wild type SRC kinase but failed to inhibit SRC gatekeeper mutants in both biochemical and cellular assays. We determined the crystal structure of ponatinib in complex with the SRC kinase domain. In addition, by structural analysis, we provided a possible explanation for why ponatinib showed different effects on SRC and other kinases with gatekeeper mutations. The resistance mechanism of SRC gatekeeper mutations to ponatinib may provide meaningful information for designing inhibitors against SRC family kinases in the future.

Rutsch et al. identified a patient with type 1 diabetes having a rare Src kinase-associated phosphoprotein 2 variant and investigated the details. As a result, they showed that rare Src kinase-associated phosphoprotein 2 c.475 G>A increases macrophage activity and promotes type 1 diabetes, as well as autoimmune and inflammatory diseases.

A major bottleneck in the development of kinase inhibitors has been the onset of drug resistance around the gatekeeper residues of Src kinase. Although recent times have seen the reports of certain second-generation kinase inhibitors which are capable of bypassing the drug resistance by circumventing kinase mutation, their kinase-binding efficacy has remained considerably weaker than that of the classical adenosine 5\'-triphosphate-competitive kinase inhibitors. Using a recently synthesized second-generation kinase inhibitor RL-45 as a template, the current work integrates fragment-based drug discovery and quantitative structure-activity relationship study with enhanced molecular dynamics simulation approaches, namely, metadynamics and replica exchange free-energy perturbation, and demonstrates how one can optimally redesign and assess novel Src kinase inhibitors, by minimal introduction of new functional moieties around template kinase inhibitor. Interestingly, unlike many synthetic kinase inhibitors, these in silico optimized small-molecule derivatives of RL-45 are found to be potentially capable of serving dual purposes, crucial for efficacy of an ideal kinase inhibitor: (a) circumventing gatekeeper residue mutation-related drug resistance in Src kinase, unlike many commercial kinase inhibitors and (b) manifesting superior resilience against unbinding from the kinase active site. The computer simulation, boosted by enhanced sampling techniques, further reveals that these designed inhibitors bring about key interactions in the form of significantly long-standing hydrogen bonds and hydrophobic pocket otherwise weak in the template bioactive kinase inhibitor, which enhance the binding efficacy of these newly designed ligands in the kinase-binding pocket.

Bypass activation of Src family kinases can confer resistance to EGFR tyrosine kinase inhibitors (TKIs) based on preclinical models. We prospectively assessed the safety and clinical activity of dasatinib and afatinib in combination for patients with resistant EGFR-mutant lung cancer.
An open-label, dose-escalation phase 1/2 trial (NCT01999985) with 2-stage expansion was conducted with 25 lung cancer patients. Dose expansion required activating EGFR mutations and progression following prior EGFR TKI.
Patients were 72% Caucasian and received median of 2 prior lines of therapy. Maximum-tolerated dose was 30 mg afatinib with 100 mg dasatinib. New or increased pleural effusions were observed in 56% of patients. No radiologic responses were observed, although several EGFR-mutant TKI-resistant patients (26%) had prolonged stable disease over 6 months. The combination reduced the EGFR mutation and T790M variant allele frequency in cell-free DNA (p < .05). Nonetheless, the threshold for futility was met, based on 6-month progression-free survival. For EGFR TKI-resistant patients, median progression-free survival was 3.7 months (95% confidence interval (CI), 2.3-5.0) and overall survival was 14.7 months (95% CI, 8.5-20.9).
The combination had a manageable toxicity profile and in vivo T790M modulation, but no objective clinical responses were observed.

The pathophysiology of pulmonary arterial hypertension (PAH) induced by protein kinase inhibitors (PKIs) remains unclear. To gain knowledge into this rare and severe pathology we performed a study combining a pharmacovigilance approach and the pharmacodynamic properties of PKIs.A disproportionality analysis on the World Health Organization pharmacovigilance database VigiBase using the reporting odds ratio (ROR) and 95% confidence interval was first performed. Then, we identified the most relevant cellular targets of interest through a systematic literature review and correlated the pharmacovigilance signals with the affinity for the different PKIs. We further performed a hierarchical cluster analysis to assess patterns of binding affinity.A positive disproportionality signal was found for dasatinib, bosutinib, ponatinib, ruxolitinib and nilotinib. Five non-receptor protein kinases significantly correlate with disproportionality signals: c-Src (r=0.79, p=0.00027), c-Yes (r=0.82, p=0.00015), Lck (r=0.81, p=0.00046) and Lyn (r=0.80, p=0.00036), all belonging to the Src protein kinase family, and TEC (r=0.85, p=0.00006). Kinases of the bone morphogenetic protein signalling pathway also seem to play a role in the pathophysiology of PKI-induced PAH. Interestingly, the dasatinib affinity profile seems to be different from that of other PKIs in the cluster analysis.The study highlights the potential role of the Src protein kinase family and TEC in PAH induced by PKIs. This approach combining pharmacovigilance and pharmacodynamics data allowed us to generate some hypotheses about the pathophysiology of the disease; however, the results have to be confirmed by further studies.

Studies on the egg plasma membrane-associated tyrosine kinase Src have shed light on the identity of the molecular machinery that is responsible for gamete interaction and possibly fusion in African clawed frog Xenopus laevis. Here we describe our protocol for identifying and analyzing molecular and cellular machinery that contributes to a variety of biological processes in the course of oogenesis, oocyte maturation, egg fertilization, and early embryogenesis in Xenopus. Our current special interest is to evaluate the hypothesis that the oocyte/egg membrane microdomain (MD)-associated uroplakin III-Src system is responsible for mediating sperm-egg membrane interaction/fusion signal to the oocyte/egg cytoplasm to initiate embryonic and zygotic development in this species. Therefore, this chapter contains a brief introduction to biology of oocytes and eggs in Xenopus and addresses the following questions: (1) What is oocyte/egg MD? (2) Why do we study oocyte/egg MD? (3) How to manipulate oocyte/egg MD? (4) What has been achieved by oocyte/egg MD studies? (5) What are the next steps in oocyte/egg MD studies?

To determine the extent of dasatinib uptake and effect on Src kinase activity in tumor, normal adjacent tissue, and blood in newly diagnosed endometrial cancer patients.
Dasatinib was dosed at 100 or 200 mg PO BID at 32 and 8 h preoperatively. Blood and tissue were collected pre-treatment and at surgery to assess active (pY419) and total Src protein (pharmacodynamics [PD]) and pharmacokinetics (PK). Plasma PK and PD were also analyzed at 2, 4 and 8 h following the second dose.
Ten patients completed the study, 5 at each dose level (DL). Average (median, standard deviation, range) 2 h plasma concentration of drug was 119 (121, 80, 226) and 236 (162, 248, 633) ng/mL, for the 100 and 200 mg DL, respectively. Average ratio of 8 h normal and tumor tissue to plasma concentration overall was 3.6 (2.3, 3.4, 9.6) and 8.3 (3.2, 11.9, 38.7), respectively. Dasatinib concentration in tumor was higher than in plasma for both DL. Four patients displayed significant reductions in pTyr419Src at ≥ 1 time points in blood, and four patients satisfied the PD activity criteria in tissue, with reductions in pTyr419Src of ≥ 60%.
This is the first study to show PK and PD effects of dasatinib in tumor tissue, allowing evaluation of tissue PD markers as a function of tumor dasatinib concentration. Dasatinib tissue concentrations at 8 h after dosing were associated with modulation of pTyr419Src, total Src protein, and pTyr419Src/Src ratio. All patients had reduction in at least one Src parameter in either tissue or blood.

Increasing evidence has shown that Chinese herbal medicine (CHM) has promising therapeutic effects in colorectal cancer (CRC); however, the active ingredients and potential targets remain unclear. In this study, we aimed to investigate the relative molecular targets of the Chinese herbs that have been found effective in treating metastatic CRC (mCRC) based on clinical data and network pharmacology. In multivariate analysis CHM resulted an independent prognostic factor. The hazard ratio was 0.103 (95% confidence interval = 0.064-0.164; P < 0.001). Compared with the non-CHM group, the median survival time of the CHM group was also improved (40 versus 12 months; P < 0.001). Eighteen out of 295 herbs showed significant correlation with survival results (P < 0.05). Bioinformatics analysis indicated that the 18 herbs realize anti-CRC activity mainly through suppressing the proliferative activity of ERBB2, peroxisome proliferator-activated receptor gamma, and retinoid X receptor, suppressing angiogenesis via inhibition of VEGFR and VEGFA expression, inhibiting the phosphatidylinositol-3-kinase/AKT1 signaling pathway directly through SRC and AKT1, and reducing tumor necrosis factor-induced inflammation.

Src family kinases (SFKs) are hyperactivated in acute myeloid leukemia (AML). SFKs impede the retinoic acid receptor, and SFK inhibitors enhance all-trans retinoic acid (ATRA)-mediated cellular differentiation in AML cell lines and primary blasts. To translate these findings into the clinic, we undertook a phase-I dose-escalation study of the combination of the SFK inhibitor dasatinib and ATRA in patients with high-risk myeloid neoplasms. Nine subjects were enrolled: six received 70 mg dasatinib plus 45 mg/m2 ATRA daily, and three received 100 mg dasatinib plus 45 mg/m2 ATRA daily for 28 days. Headache and QTc prolongations were the only two grade 3 adverse events observed. No significant clinical responses were observed. We conclude that the combination of 70 mg dasatinib and 45 mg/m2 ATRA daily is safe with acceptable toxicity. Our results provide the safety profile for further investigations into the clinical efficacy of this combination therapy in myeloid malignancies.