This is an Open Access article licensed under the terms of the Creative Commons AttributionNonCommercial 3.0 Unported license (CC BY-NC) (www.karger.com/OA-license), applicable to the online version of the article only. Distribution permitted for non-commercial purposes only. Key Words Diabetes mellitus • High-glucose • hERG • LQT • Unfolded protein response • InsulinAbstract Background/Aims: Abnormal QT prolongation is the most prominent cardiac electrical disturbance in patients with diabetes mellitus (DM). It is well known that the human ether-ago-go-related gene (hERG) controls the rapid delayed rectifier K + current (I Kr ) in cardiac cells. The expression of the hERG channel is severely down-regulated in diabetic hearts, and this down-regulation is a critical contributor to the slowing of repolarization and QT prolongation. However, the intracellular mechanisms underlying the diabetes-induced hERG deficiency remain unknown. Methods: The expression of the hERG channel was assessed via western blot analysis, and the hERG current was detected with a patch-clamp technique. Results: The results of our study revealed that the expression of the hERG protein and the hERG current were substantially decreased in high-glucose-treated hERG-HEK cells. Moreover, we demonstrated that the high-glucose-mediated damage to the hERG channel depended on the down-regulation of protein levels but not the alteration of channel kinetics. These discoveries indicated that high glucose likely disrupted hERG channel trafficking. From the western blot and immunoprecipitation analyses, we found that high glucose induced trafficking inhibition through an effect on the expression of Hsp90 and its interaction with hERG. Furthermore, the high-glucose-induced inhibition of hERG channel trafficking could activate the unfolded protein response (UPR) by up-regulating the expression levels of activating transcription factor-6 (ATF-6) and the ER chaperone protein calnexin. In addition, we demonstrated that 100 nM insulin up-regulated the expression of the hERG channel and rescued the hERG channel repression caused by high glucose. Conclusion: The results of our study provide the first evidence of a high-glucose-induced hERG channel deficiency resulting from the inhibition of channel trafficking. Furthermore, insulin promotes the expression of the hERG channel and ameliorates the high-glucose-induced inhibition of the hERG channel.

WX-0593 (Iruplinalkib) is a novel, highly selective oral ALK and ROS1 tyrosine kinase inhibitor (TKI). In this study, the safety, antitumor activity, and pharmacokinetics of WX-0593 were evaluated in advanced non-small cell lung cancer (NSCLC) patients with ALK or ROS1 rearrangement. In the dose-escalation phase and dose-expansion phase, patients were treated with WX-0593 until disease progression, unacceptable toxicity, or subject withdrawal. In the dose-escalation phase, the primary endpoints were maximum tolerated dose (MTD), dose-limiting toxicity (DLT), and safety assessed by investigators. In the dose-expansion phase, the primary endpoint was objective response rate (ORR) assessed by investigators. Between September 25, 2017 and October 15, 2018, a total of 153 patients received WX-0593 treatment. Two dose-limiting toxicities (DLTs) including one grade 3 QT interval prolonged and one grade 2 chronic heart failure were reported at the dose of 300 mg in one patient. MTD was not reached. Overall, 140 of the 152 (92%) patients experienced treatment-related adverse events (TRAEs) and 35 of the 152 (23%) patients had TRAEs ≥grade 3. The overall ORR was 59.3% (32 of 54) for the dose-escalation phase and 56.6% (56 of 99) for the dose-expansion phase. For patients who were ALK-rearranged and ALK TKI naive, the ORR were 81.0% (17 of 21) in the dose-escalation phase and 76.3% (29 of 38) in the dose-expansion phase, and for patients who previously received crizotinib as the only ALK TKI, the ORR were 38.1% (8 of 21) and 45.7% (21 of 46) for the two phases, respectively. For patients who were ROS1-rearranged, the ORR were 30.0% (3 of 10) in the dose-escalation phase and 44.4% (4 of 9) in the dose-expansion phase. WX-0593 showed favorable safety and promising antitumor activity in advanced NSCLC patients with ALK or ROS1 rearrangement.

Background Iruplinalkib (WX-0593) is an anaplastic lymphoma kinase (ALK)/c-ros oncogene 1 (ROS1) tyrosine kinase inhibitor. Here we reported the single-arm, phase II study (INTELLECT) results of the efficacy and safety of iruplinalkib for ALK-positive crizotinib-resistant advanced non-small cell lung cancer (NSCLC) patients. Methods ALK-positive crizotinib-resistant advanced NSCLC patients aged ≥18 years, with Eastern Cooperative Oncology Group performance status of 0–2 were eligible. Patients received iruplinalkib 180 mg orally once daily for a 21-day cycle with a 7-day lead-in phase at 60 mg orally once daily. The primary endpoint was the independent review committee (IRC)-assessed objective response rate (ORR). Results From August 7, 2019, to October 30, 2020, 146 patients were included. As of the data cut-off date on November 30, 2021, the median follow-up time was 18.2 months (95% confidence interval [CI] 16.8–18.8). IRC-assessed ORR and disease control rate (DCR) were 69.9% (95% CI 61.7–77.2%) and 96.6% (95% CI 92.2–98.9%), respectively. Investigator-assessed ORR and DCR were 63.0% (95% CI 54.6–70.8%) and 94.5% (95% CI 89.5–97.6%), respectively. Investigator-assessed median duration of response and progression-free survival (the same as median time to progression) were 13.2 months (95% CI 10.4–17.7) and 14.5 months (95% CI 11.7–20.0), respectively. Corresponding IRC-assessed results were 14.4 months (95% CI 13.1–not evaluable [NE]), 19.8 months (95% CI 14.5–NE), and NE (95% CI 14.5–NE), respectively. Investigator-assessed intracranial ORRs were 46% (41/90, 95% CI 35–56%) in patients with central nervous system metastases and 64% (27/42, 95% CI 48–78%) in patients with measurable intracranial lesions. Overall survival data were immature. Treatment-related adverse events (TRAEs) occurred in 136/146 (93.2%) patients. The most common TRAEs were aspartate aminotransferase increased (63 [43.2%]), alanine aminotransferase increased (54 [37.0%]), and blood creatine phosphokinase increased (51 [34.9%]). Dose interruption, reduction, and discontinuation due to TRAEs occurred in 21 (14.4%), 16 (11.0%), and four (2.7%) patients, respectively. Conclusions In this study, iruplinalkib (WX-0593) demonstrated favorable efficacy and manageable safety profiles in patients with ALK-positive crizotinib-resistant advanced NSCLC. Iruplinalkib could be a new treatment option for this patient population. Trial registration Center for Drug Evaluation of National Medical Products Administration of China: CTR20190789, registered on April 28, 2019; ClinicalTrials.gov: NCT04641754, registered on November 24, 2020.

The human ether-a-go-go related gene (hERG) encodes the rapid delayed rectifier K+ channel. hERG not only serves an important role in heart muscle and cardiomyocyte excitability by regulating action potential repolarization, but also represents a selective advantage for cancer cell proliferation. Arsenic trioxide is a traditional Chinese medicine, which has been previously identified as an efficient tumor suppressor, particularly in the treatment of acute pro-myelocytic leukemia. However, studies have also reported that long-term exposure to arsenicals may lead to the formation of malignant tumors. In the present study, the effect of low-dose arsenic trioxide on the proliferation and apoptosis of tumor cells was investigated, as were the potential underlying mechanisms of this effect. The data demonstrated that low-dose arsenic trioxide (0.1 µM) enhanced the viability and apoptosis of tumor cells expressing hERG channels following long-term incubation. However, in tumor cells lacking hERG channels, low-dose arsenic trioxide had no effect. Therefore, we hypothesized that this hormesis effect of low-dose arsenic trioxide on tumor cells may be associated with the hERG channel. Furthermore, low dose arsenic trioxide promoted the hERG-channel current by changing the kinetics of channel gating and prolonging the open-channel stage. Simultaneously, high-dose As2O3 (1 or 10 µM) significantly reduced the expression of hERG in tumor cells compared with the control group, which resulted in reduced proliferation rate and promotion of apoptotic rate. The results of the present study demonstrate that the dual effects of arsenic trioxide on hERG channels vary according to concentration, resulting in the dual effects on tumor cells. This provides a theoretical basis for the potential clinical application of arsenic trioxide, suggesting that hERG channels are an important target in preventing and treating tumorigenesis during arsenicosis.

The hERG gene encodes the pore-forming α-subunit of the rapidly activating delayed rectifier potassium channel (IKr), which is important for cardiac repolarization. Reduction of IhERG due to genetic mutations or drug interferences causes long QT syndrome, leading to life-threatening cardiac arrhythmias (torsades de pointes) or sudden death. Probucol is a cholesterol-lowering drug that could reduce hERG current by decreasing plasma membrane hERG protein expression and eventually cause long QT syndrome. Here, we investigated the mechanisms of probucol effects on IhERG and hERG-channel expression. Our data demonstrated that probucol reduces SGK1 expression, known as SGK isoform, in a concentration-dependent manner, resulting in downregulation of phosphorylated E3 ubiquitin ligase Nedd4-2 expression, but not the total level of Nedd4-2. As a result, the hERG protein reduces, due to the enhanced ubiquitination level. On the contrary, carbachol could enhance the phosphorylation level of Nedd4-2 as an alternative to SGK1, and thus rescue the ubiquitin-mediated degradation of hERG channels caused by probucol. These discoveries provide a novel mechanism of probucol-induced hERG-channel deficiency, and imply that carbachol or its analog may serve as potential therapeutic compounds for the handling of probucol cardiotoxicity.

9073 Background: This single-arm, multicenter phase II trial aimed to evaluate the efficacy and safety of second generation ALK/ROS1 TKI WX-0593 (iruplinalkib) in advanced ALK/ ROS1-positive non-small cell lung cancer (NSCLC). We reported the results from the crizotinib-resistant ALK-positive cohort. Methods: Patients aged ≥18 years, with histologically or cytologically confirmed ALK-positive NSCLC, progression on ≥12-week crizotinib treatment, ≥one measurable lesion according to RECIST v1.1, and ECOG PS of 0 to 2 were eligible. Patients received oral WX-0593 180 mg once daily (with a 7-day lead-in period at 60 mg once daily). The primary endpoint was confirmed overall response rate (ORR) by independent review committee (IRC) per RECIST v1.1. Secondary endpoints included confirmed disease control rate (DCR) by IRC, ORR, DCR, duration of response (DoR), progression-free survival (PFS), time to progression (TTP), intracranial ORR (iORR) per RANO-brain metastases criteria by investigator (INV), overall survival (OS), safety, and Cmax,ss. Results: Between August 7, 2019 and October 30, 2020, totally 146 patients were enrolled. The data cutoff date was March 10, 2021. The median follow-up was 9.3 months (IQR 6.3-14.1). 90 (61.6%) patients had brain metastases, of which 41 (46%) had measurable intracranial lesions and 20 (22%) received prior radiotherapy to brain. 56 (38.4%) patients received prior chemotherapy. The IRC-assessed ORR was 67.8% (95% CI 59.6%-75.3%). Efficacy data were detailed in the Table. Additionally, subgroup analyses indicated IRC-assessed ORR were slightly higher in the patients without brain metastases (79% vs 61%) or prior radiotherapy to brain (66% vs 45%). Patients with prior chemotherapy or not had similar results (71% vs 66%). The iORR was 63% (95% CI 47%-78%) in pts with measurable intracranial lesions. OS data were immature. 134 (91.8%) of 146 experienced treatment-related adverse events (TRAEs). The most common TRAEs were AST increased (60 [41.1%]), ALT increased (52 [35.6%]), and blood creatine phosphokinase increased (49 [33.6%]). Dose reduction and discontinuation due to TRAE, and serious TRAEs occurred in 15 (10.3%), three (2.1%), and six (4.1%), respectively. No treatment-related death was reported. Drug concentration reaches steady state at Day 21 (Cmax,ss =255.4 ng/mL). Conclusions: WX-0593 showed promising activity against ALK-positive NSCLC after crizotinib resistance and favorable safety profile, demonstrating WX-0593 could be a new treatment option for this patient population. Clinical trial information: NCT04641754. [Table: see text]