EGFR Stability Research Articles

Long-Term Results from an Open-Label Extension Study of Atacicept for the Treatment of IgA Nephropathy.

Key Points Participants who completed a 36-week double-blind study of atacicept were eligible for a 60-week, open-label extension study.Atacicept 96-week treatment resulted in sustained reductions in galactose-deficient IgA1, hematuria, and urine protein-creatinine ratio.The slope of the eGFR was similar to that observed in the general population without kidney disease. Background B-cell activating factor (BAFF) and A proliferation-inducing ligand (APRIL) play key roles in the pathogenesis of IgA nephropathy. Atacicept is a novel fully humanized fusion protein, self-administered at home by subcutaneous injection, that binds and inhibits BAFF and APRIL. By inhibiting BAFF and APRIL, atacicept targets the underlying B-cell–mediated pathogenesis driving disease progression. This study evaluated the long-term efficacy and safety of atacicept in patients with IgA nephropathy over 96 weeks. Methods Participants with IgA nephropathy who received atacicept (25, 75, or 150 mg) or placebo in a 36-week phase 2b, randomized, blinded trial were enrolled in an open-label extension study and received atacicept 150 mg for an additional 60 weeks. Key efficacy outcomes were changes in galactose-deficient IgA1 (Gd-IgA1), percentage of participants with hematuria, urine protein-creatinine ratio (UPCR), and eGFR over 96 weeks. Long-term safety data were also evaluated. Results There were 113 participants (67 [59%] male; 46 [41%] female) who ranged in age from 18 to 67 years who received ≥1 atacicept dose. Over 96 weeks, safety data demonstrated that atacicept was generally well tolerated. There were also sustained reductions (mean±SEM) in Gd-IgA1 (−66%±2%), percentage of participants with hematuria (−75%; 95% confidence intervals, −87 to −59; in participants with baseline hematuria), and UPCR (−52%±5%). The mean annualized slope of eGFR was −0.6±0.5 ml/min per 1.73 m2 through 96 weeks. Conclusions Atacicept was also well tolerated over the duration of the study. Atacicept treatment reduced Gd-IgA1, hematuria, and UPCR with stabilization of eGFR through 96 weeks. Clinical Trial registry name and registration number: Atacicept in Subjects with IgA Nephropathy (ORIGIN 3), NCT04716231.

Efficacy and Safety of Ravulizumab in IgA Nephropathy: A Phase 2 Randomized Double-Blind Placebo-Controlled Trial.

Key Points This phase 2, double-blind, randomized controlled trial evaluated the complement C5 inhibitor, ravulizumab, in adults with IgA nephropathy.A 30.1% (90% confidence interval, 13.7% to 43.5%) relative reduction in proteinuria for ravulizumab versus placebo was observed at approximately 6 months.Treatment with ravulizumab was well tolerated. Background The complement system plays a central role in the pathogenesis of IgA nephropathy. We present findings from a phase 2 trial of ravulizumab, a complement C5 inhibitor. Methods The Study of Ravulizumab in Proliferative Lupus Nephritis or IgA Nephropathy (NCT04564339) was a randomized, double-blind, placebo-controlled trial of ravulizumab in addition to standard of care. Adults with IgA nephropathy, proteinuria ≥1 g/d, and eGFR ≥30 ml/min per 1.73 m2, and on stable renin-angiotensin blockade were randomized 2:1 to ravulizumab (intravenous every 8 weeks) or placebo for 26 weeks. From week 26–50, all participants received open-label ravulizumab. The primary end point was percentage change in proteinuria from baseline (BL) to week 26. Secondary end points included change in proteinuria at week 50 and eGFR. Safety, pharmacokinetics, and pharmacodynamics were evaluated. Results Forty-three patients were randomized to ravulizumab and 23 to placebo. At week 26, a statistically significant reduction in proteinuria was observed with ravulizumab versus placebo: −41.9% (95% confidence interval [CI], −50.2% to −32.0%) change in urine protein with ravulizumab and −16.8% (95% CI, −31.8% to 1.6%) change with placebo (30.1% treatment effect; P = 0.005). At week 50, there was a −44.8% (95% CI, −55.1% to −32.1%) change from BL in urine protein with ravulizumab, and in patients who crossed over from placebo to ravulizumab at week 26, the change from BL (week 0) to week 50 was −45.1% (−58.0% to −28.4%). The least squares mean change in eGFR from BL to week 26 with ravulizumab was 0.2 (95% CI, −2.3 to 2.7) ml/min per 1.73 m2 and with placebo was −4.5 (−7.9 to −1.1) ml/min per 1.73 m2. From BL to week 50, the least squares mean change in eGFR with ravulizumab was −3.9 (95% CI, −6.4 to−1.3) ml/min per 1.73 m2, and in patients who crossed over from placebo to ravulizumab at week 26, it was −6.3 (−9.7 to −2.9) ml/min per 1.73 m2. Ravulizumab was well tolerated, with an adverse event profile similar to that for placebo. Conclusions An early, sustained, and clinically meaningful reduction in proteinuria and trend toward stabilization of eGFR were observed with ravulizumab versus placebo. A phase 3 trial (NCT06291376) is enrolling. Clinical Trial registry name and registration number: Study of Ravulizumab in Proliferative Lupus Nephritis or IgA Nephropathy, NCT04564339.

TSPAN4 influences glioblastoma progression through regulating EGFR stability

Glioblastoma (GBM) is characterized by high morbidity, mortality, and low cure rates. Recent studies suggest that TSPAN4 is recognized as a marker protein for migrasomes, a vesicular organelle associated with cell migration. However, the intrinsic role of TSPAN4 in cancers has not been clarified, especially in GBM. Here, we report that TSPAN4 promotes GBM progression by interacting with epidermal growth factor receptor (EGFR) and regulating its stability. Clinically, TSPAN4 is highly expressed in GBM and is significantly correlated with poor prognosis. Functionally, TSPAN4 knockdown dramatically inhibits GBM cell proliferation and invasion invitro, as well as tumorigenicity invivo. Conversely, overexpression of TSPAN4 facilitates GBM progression. Mechanistically, TSPAN4 knockdown disrupts interaction with EGFR, destabilizing its expression and inactivating EGFR and downstream signaling pathways, such as MEK/ERK, STAT3, and AKT. Our study reveals that TSPAN4 drives GBM progression through regulating EGFR stability and could be a potential target for cancer therapy.

#277 Update to the long-term safety and efficacy of iptacopan in C3G: 33-month extension study data from patients enrolled in a phase 2 study

Abstract Background and Aims Complement 3 glomerulopathy (C3G), due to dysregulation of the alternative complement pathway (AP), is an ultra-rare primary glomerulonephritis. Iptacopan (LNP023) is an oral, proximal complement inhibitor that specifically binds factor B and inhibits the AP. We previously reported the primary endpoint data from the Phase (Ph) 2 extension study (NCT03955445), showing proteinuria reduction (57% [p < 0.0001]) and estimated glomerular filtration rate (eGFR) improvement (by +6.83 mL/min/1.73 m2 [p = 0.0174]) from baseline, following 12 months (M) of treatment with iptacopan in patients with C3G. Here we present further long-term efficacy and safety data from patients with C3G and recurrent C3G (post-kidney transplantation), who completed 33M of treatment with iptacopan (NCT03955445). Method Adults with C3G disease (Cohort A) or C3G recurrence post-transplantation (Cohort B) received iptacopan 200 mg twice-daily (bid) for at least 12 weeks in the Ph2 study (NCT03832114) before entering the open label extension study (NCT03955445). Long-term efficacy was assessed by a number of renal endpoints, including a 2-component composite renal endpoint (eGFR stability [≤10% reduction] and ≥50% proteinuria reduction). Long-term safety and tolerability of iptacopan was continually monitored. Results Of 27 patients completing the Ph2 study (NCT03832114), 26 (16 Cohort A, 10 Cohort B) entered the extension study treatment with iptacopan 200 mg bid; 22 patients (14 Cohort A, 8 Cohort B) completed the 33M visit (i.e., 3M in the Ph2 study and 30M in the extension study). In Cohort A, 42.9% of patients met the 2-component composite renal endpoint criteria at 33M. Proteinuria (first morning void [FMV] urine protein–creatinine ratio [UPCR]) was reduced by 41% (p = 0.0097) compared to baseline. eGFR stabilized or improved in most patients (13/16) over time and change from baseline at the 33M time-point was −3.18 mL/min/1.73 m2 (p = 0.3512). C3 levels increased by 275% (p < 0.0001) from baseline. In Cohort B, eGFR change from baseline at the 33M time-point was −6.34 mL/min/1.73 m2 (p = 0.0571), and C3 levels increased by 102%. Baseline proteinuria values (FMV UPCR) were within the normal range for most participants in Cohort B and remained so during iptacopan treatment. Iptacopan was generally well-tolerated, and most adverse events were of mild severity in both cohorts. Biomarkers demonstrated substantial AP inhibition. Conclusion Long-term treatment with iptacopan was associated with sustained reduction in proteinuria in patients with C3G (Cohort A), and preservation of eGFR. These improvements in kidney function were associated with substantial inhibition of the AP leading to normalization of serum C3. Iptacopan was well-tolerated with no new safety findings in the long term, in patients with C3G, including those with recurrence post-transplantation on top of broad triple immunosuppression. The ongoing Ph3 APPEAR-C3G study (NCT04817618) is evaluating the efficacy and safety of iptacopan in patients with C3G.

#812 Phase 2b ORIGIN study open label extension with atacicept in patients with IgA nephropathy and persistent proteinuria: week 72 interim analysis

Abstract Background and Aims IgA nephropathy (IgAN), the most common primary glomerulonephritis and a significant contributor to ESKD worldwide, is characterized by elevated serum levels of galactose-deficient IgA1 (Gd-IgA1). The production of Gd-IgA1 and its autoantibodies is driven by both the B-cell Activating Factor (BAFF) and A PRoliferation-Inducing Ligand (APRIL) signaling pathways that stimulate maturation, differentiation, and effector function of B cells and plasma cells. Atacicept is a fusion protein targeting both BAFF and APRIL in clinical development for IgAN treatment. The Phase 2b ORIGIN study met the primary endpoint with statistically significant urine protein:creatinine ratio (UPCR) reduction at 24 weeks vs placebo. At 36 weeks, atacicept 150 mg achieved statistically significant and clinically meaningful UPCR reduction, eGFR stabilization, and Gd-IgA1 reduction vs placebo, with similar safety to placebo. This interim analysis reports 72-week results from the open-label extension period. Method The randomized, double-blind, placebo-controlled Phase 2b ORIGIN study included 116 participants with biopsy-proven IgAN, 24 h urine protein >0.75 g/day or UPCR >0.75 g/g, and eGFR ≥30 mL/min/1.73 m2 despite optimized renin–angiotensin system blockade. Participants were randomized to atacicept 150, 75, or 25 mg, vs placebo (2:2:1:2), self-administered by subcutaneous injection once weekly for up to 36 weeks. The double-blind randomized treatment period was followed by an open-label extension in which participants could receive atacicept 150 mg for up to 60 additional weeks, for a total of 96 weeks. For this interim analysis, changes from baseline in eGFR, natural log transformed UPCR, and Gd-IgA1 through 72 weeks were analyzed using a mixed-effects model for repeated measurements. Microscopic hematuria was evaluated on urine dipstick and participants with hematuria grade 1+ or higher at baseline were evaluated for resolution, defined as a decrease to negative/trace, at 72 weeks. Results Of 116 randomized participants in the double-blind period, 106 participants (91%) completed 72 weeks of treatment. At 72 weeks, eGFR total slope estimate was 0.0 mL/min/1.73m2/year and eGFR change from baseline was 0 mL/min/1.73m2 in all participants originally randomized to atacicept (all-atacicept group; n = 82). After switching to open-label atacicept 150 mg, the original placebo group showed eGFR stabilization with −3.2 mL/min/1.73m2 change from baseline at 72 weeks vs −4.9 mL/min/1.73m2 at 36 weeks (Figure 1). At 72 weeks, UPCR change from baseline was −45% in the all-atacicept group and the placebo switch group showed a −47% UPCR change from baseline at 72 weeks vs +3% at 36 weeks (Figure 2). Open-label atacicept 150 mg was also associated with rapid Gd-IgA1 reduction in the placebo switch group at 48 weeks that was sustained through 72 weeks. Hematuria resolution was observed at 72 weeks in 81% (35/43) of participants in the all-atacicept group and 59% (10/17) in the placebo switch group. Atacicept was generally well tolerated during the open-label extension, with a similar rate of infections compared to the double-blind period and one study drug-related serious adverse event. Conclusion At 72 weeks, treatment with atacicept 150 mg was associated with sustained eGFR stability and deepening UPCR reductions, as well as a reversal of the downward eGFR decline in the placebo switch group. Sustained reductions in hematuria were also observed. The open-label extension showed a favorable safety profile similar to the double-blind period. These results support atacicept 150 mg as a potential disease-modifying treatment for IgAN.

#1467 Pegcetacoplan for post-transplant recurrent C3 glomerulopathy or immune complex membranoproliferative glomerulonephritis in NOBLE: 12-week evolution

Abstract Background and Aims C3 glomerulopathy (C3G) and primary immune complex membranoproliferative glomerulonephritis (IC-MPGN) are rare diseases caused by uncontrolled complement activation, resulting in excess deposition of C3 breakdown products in the kidneys, which leads to kidney damage and eventually kidney failure. Kidney transplantation is an option for end-stage kidney disease, but disease recurrence is common (up to 67% of patients), and up to 50% of transplant recipients lose renal allografts due to recurrence. Pegcetacoplan is a targeted C3 and C3b inhibitor that may prevent excess deposition of C3 and C5 breakdown products and subsequent glomerular inflammation and kidney damage in patients with C3G or IC-MPGN, potentially improving clinical outcomes. NOBLE (NCT04572854) was the first prospective randomized controlled trial of pegcetacoplan vs standard of care (SOC) in post-transplant patients with recurrent C3G or IC-MPGN. Method Adult patients were randomized 3:1 to subcutaneous pegcetacoplan 1080 mg twice weekly plus SOC (n = 10) or SOC only (n = 3) for 12 weeks followed by a 40-week non-controlled period in which all patients received pegcetacoplan. Primary and secondary endpoint results for Week-12 data have been reported. We conducted a patient-level post hoc analysis to describe key histology changes from renal biopsy (C3c staining, C3G histologic index activity score), clinical parameters (urine protein-to-creatinine ratio [uPCR; calculated from triplicate first-morning spot urine], estimated glomerular filtration rate [eGFR]), and biomarkers (serum C3, plasma sC5b-9) through Week 12. The C3G histologic index uses a semiquantitative scale of 0–3 for 7 markers of activity (mesangial hypercellularity, endocapillary proliferation, membranoproliferative morphology, leukocyte infiltration, cellular and/or microcellular crescent formation, fibrinoid necrosis, and interstitial inflammation), for a total activity score of 0–21. eGFR stability was defined as a decrease of no more than 25% versus baseline. Results Among the 10 pegcetacoplan-treated patients, 7 (70%) had 1 previous kidney transplant, 2 (20%) had 2, and 1 (10%) had 3. The mean (range) time to disease recurrence after most recent transplant was 10.8 (0.4–31.8) months and from most recent recurrence to randomization was 12.2 (2.1–37.7) months, with 60% randomized >6 months post-disease recurrence. Among the 3 SOC-only patients, 2 (66.7%) had 1 transplant and 1 (33.3%) had 2. Mean (range) time to recurrence was 32.8 (4.6–63.8) months and to randomization was 33.9 (7.0–65.4) months. At Week 12, 8 (80%) pegcetacoplan-treated patients had a reduction in C3c staining of at least 1 order of magnitude. Of these 8, 7 (70%) had a decrease in activity score, and 6 of these 7 (60%) had a decrease in proteinuria. Four (40%) patients had reduced C3c staining, decreased activity score, and cleared electron microscopy deposits at Week 12. eGFR remained stable in 9 (90%) patients. Six of 9 (67%) patients with available Week-12 data (4 of 5 patients with >1 g/g uPCR at baseline) had a reduction in uPCR with 5 of the 6 achieving ≥50% uPCR reduction (Table). All pegcetacoplan-treated patients had increased serum C3, as expected, and 9 (90%) had decreased sC5b-9. At Week 12, no TEAEs led to study discontinuation, treatment withdrawal, or death. No encapsulated bacterial infections or events of rejection/graft loss related to the study drug were reported. Conclusion As early as Week 12, more than half (6/10 [60%]) of post-transplant patients with recurrent C3G or IC-MPGN treated with pegcetacoplan achieved reductions in C3c staining, activity score of C3G histology index, and proteinuria, suggesting that pegcetacoplan targets the underlying pathophysiology of the C3G/IC-MPGN in kidney transplant recipients. The safety and efficacy of pegcetacoplan will be further evaluated at Week 52 of the NOBLE study and as part of the Phase 3 VALIANT (NCT05067127) trial, which enrolled patients with C3G or primary IC-MPGN who have native kidney or post-transplant disease.

#123 Impact of atacicept on hematuria in IGA nephropathy: post-hoc analysis of the phase 2b ORIGIN study

Abstract Background and Aims Patients with IgA nephropathy (IgAN) and persistent hematuria during follow up have a greater decline in renal function than those with minimal or no hematuria, while hematuria resolution has been independently associated with less decline in renal function [1, 2]. Atacicept is a fusion protein targeting both BAFF and APRIL in clinical development for IgAN. The Phase 2b ORIGIN study met the primary endpoint with statistically significant urine protein:creatinine ratio (UPCR) reduction at 24 weeks for atacicept vs placebo. At 36 weeks, atacicept 150 mg achieved statistically significant and clinically meaningful UPCR reduction, eGFR stabilization, and robust reduction of galactose-deficient IgA1 vs placebo, with similar safety to placebo. This post-hoc analysis evaluates changes in hematuria during treatment with atacicept vs placebo over 36 weeks. Method The randomized, double-blind, placebo-controlled Phase 2b ORIGIN study included 116 participants with biopsy-proven IgAN, 24h urine protein >0.75 g/day or UPCR >0.75 g/g, and eGFR ≥30 mL/min/1.73 m2 despite optimized renin–angiotensin system blockade. Participants were randomized to atacicept 150, 75, or 25 mg vs placebo (2:2:1:2) self-administered by subcutaneous injection once weekly for up to 36 weeks. Microscopic hematuria was evaluated at weeks 2, 4, 12, 24, and 36 via urine dipstick at a centralized lab, and hematuria levels were graded negative/trace, 1+, 2+, or 3+. Hematuria improvement was defined as a decrease by ≥1 grade, and resolution was defined as a decrease to negative/trace. Results In the intent-to-treat population, 15 of 33 (45%) participants who received atacicept 150 mg and 19 of 34 (56%) who received placebo had hematuria (1+ or greater) at baseline. Of these, 87% (n = 13/15) on atacicept 150 mg had improved hematuria at 36 weeks vs 32% (n = 6/19) on placebo (p = 0.002), with 80% (n = 12/15) on atacicept 150 mg achieving resolution to negative/trace hematuria vs 5% (n = 1/19) on placebo (p < 0.0001) (Figure). The atacicept 150 mg group steadily improved to lower hematuria grades over 36 weeks, with improvement occurring as early as 4 weeks, while the placebo group had no improvement in hematuria over time. The majority of participants without hematuria at baseline maintained negative or trace levels at 36 weeks. Conclusion In a post-hoc analysis, atacicept treatment was associated with hematuria resolution at 36 weeks in a substantially greater percentage of participants as compared with placebo, with improvements seen as early as 4 weeks. These results add to the growing body of evidence supporting atacicept as a potential disease-modifying treatment for IgAN. Atacicept 150 mg is currently being evaluated in a global Phase 3 randomized placebo-controlled trial.

#425 Felzartamab (anti-CD38) in patients with IgA Nephropathy—interim results from the IGNAZ study

Abstract Background and Aims Most patients with IgA nephropathy (IgAN) will progress to kidney failure within 10-15 years of diagnosis. Sustained proteinuria is the best predictor of adverse long-term kidney outcomes and is a surrogate marker for efficacy. CD38+ plasma cells are likely the main source of pathogenic Gd-IgA1, and the related autoantibodies in IgAN. Felzartamab (felza; HIB202) is a recombinant purified human immunoglobulin G1 (IgG1) monoclonal antibody (mAb) that binds to CD38 on plasma cells and is being studied across immune-mediated kidney diseases such as IgAN, Primary Membranous Nephropathy, Lupus Nephritis, and Antibody Mediated Rejection. The primary aims of the IGNAZ study were to assess: 1) efficacy of felza compared to placebo on urine protein:creatinine ratio (UPCR) and estimated glomerular filtration rate (eGFR) change from baseline, and 2) the relationship between exposure, safety, and efficacy in each of 3 dose groups vs. placebo. Interim results with 15 months of follow-up from this 24-month trial are presented. Method In Part 1, 48 IgAN subjects were randomized in a 1:1:1:1 ratio across a placebo and 3 active arms in this multicenter, double-blind placebo-controlled, phase IIa trial. The M1, M2, and M3 active arms received 2 doses in 15 days, 5 doses in 2 months, and 9 doses in 5 months, respectively. In Part 2, 6 Japanese subjects received the M3 regimen, open-label, and have been followed for 9 months. Key inclusion criteria included ages 18-80 years, biopsy confirmed diagnosis of IgAN within the past 8 years, proteinuria at screening ≥1.0 g/d, eGFR ≥30 ml/min/1.73 m2 (by CKD-EPI), and background stable and maximally tolerated renin angiotensin system inhibitors. Results 48 randomized subjects were enrolled at 28 sites in the US and in 14 different countries in Europe and in Asia, of which 46 completed the treatment phase. Mean (SD) baseline characteristics (Parts 1 and 2 combined): age 41.6 (12.3) yrs, UPCR 1.67 (1.0) g/g, eGFR 74.6 (30.3) ml/min/1.73 m2. 67% of subjects were male. Intention-to-treat with felza demonstrated rapid, clinically meaningful reductions in UPCR with the maximal treatment effect being observed in the M3 9-dose regimen. In Part 1, percentage change from baseline in UPCR was −14% for placebo and −25% for M3 9-dose arm at month 3, and +9% for placebo and −35% for M3 at month 6 (Fig. A). Reductions in proteinuria observed at month 6 persisted until Month 15, 10 months after the last dose: +6% and −38% mean UPCR change from baseline for placebo and the M3 9-dose arm, respectively (Fig. B). Relatively stable eGFR values were observed for the felza arms compared to loss of eGFR in the placebo arm. Rapid, durable reductions in IgA and Gd-IgA1 levels were seen across the dosing arms, with reductions lasting 10 months after the last dose (Fig. C). IgG recovery occurred faster off-treatment than IgA. Results in the Part 2 subjects were similar to the Part 1 M3 cohort through 9 months. There were no apparent dose-dependent adverse events and no exposure-safety relationship. Treatment-emergent adverse events (TEAEs) were generally of mild or moderate intensity or toxicity grade. The most common TEAE assessed as related by study investigator was infusion related reactions (IRR), most of which occurred on the first infusion. There was one treatment-related serious AE due to an IRR. Five subjects discontinued treatment due to IRRs or drug hypersensitivity; for four of the five subjects, the infusion rate was higher than protocol-specified or had an error in pre-medication. TEAE infections were comparable between placebo and felza arms: Placebo (33.3%), M1 (33.3%), M2 (36.4%), M3 (38.5%), Part 2 (50.0%); all were Grades 1 or 2, and non-serious. Conclusion This proof-of-concept study highlights the potential for disease modification in IgAN with the anti-CD38 mAb felza and supports continued research as a potential treatment for high-risk IgAN patients. Felza treatment resulted in clinically meaningful, prolonged UPCR reductions and eGFR stabilization sustained ≥10 months after dosing was completed. Felza was generally well tolerated with rapid recovery of IgG with durable reductions in IgA and pathogenic Gd-IgA1 levels.

Identification of a novel SH3PXD2B::FER fusion in a case of plexiform myofibroblastic tumor and review of the literature

AbstractFibroblastic/myofibroblastic tumors encompass a wide spectrum of lesions. Among them, plexiform myofibroblastoma (PM) represents a rare and distinctive entity recently described as mostly occurring in children and with a favorable prognosis. Histologically, PM shows SMA, CD34, and desmin expression in most cases, while it is negative for β‐catenin and S100. To date, the molecular mechanisms underlying PM tumorigenesis remain largely unknown. Herein, we describe a 7‐year‐old girl with a myofibroblastic lesion with plexiform features arising in the right deltoid region. The tumor proved positive for SMA staining, in absence of desmin, CD34, S100, and EMA expression. RNAseq analysis revealed a novel in‐frame SH3PXD2B::FER fusion gene. The FER gene encodes a cytoplasmic tyrosine kinase which is implicated in several biologically aggressive tumors, where it is overexpressed and associated with EGFR recycling and stabilization. In our case, immunohistochemical analysis revealed a strong positivity for EGFR indicating an upregulation of EGFR transcription that might correlate with the novel chimeric protein involving the FER kinase domain. To our knowledge, the SH3PXD2B::FER fusion has never been reported previously. Whether the current case represents an example of a plexiform myofibroblastic tumor or a distinct tumor entity remains to be determined.

Comprehensive Analysis of MICALL2 Reveals Its Potential Roles in EGFR Stabilization and Ovarian Cancer Cell Invasion.

Molecules interacting with CasL (MICALs) are critical mediators of cell motility that act by cytoskeleton rearrangement. However, the molecular mechanisms underlying the regulation of cancer cell invasion remain elusive. The aim of this study was to investigate the potential role of one member of MICALs, i.e., MICALL2, in the invasion and function of ovarian cancer cells. We showed by bioinformatics analysis that MICALL2 expression was significantly higher in tissues of advanced-stage ovarian cancer and associated with poor overall survival of patients. MICALL2 was strongly correlated with the infiltration of multiple types of immune cells and T-cell exhaustion markers. Moreover, enrichment analyses showed that MICALL2 was involved in the tumor-related matrix degradation pathway. Mechanistically, MMP9 was identified as the target gene of MICALL2 for the regulation of invadopodium formation and SKOV3, HO-8910PM cell invasion. In addition, EGFR-AKT-mTOR signaling was identified as the downstream pathway of MICALL2 in the regulation of MMP9 expression. Furthermore, MICALL2 silencing promoted EGFR degradation; however, this effect was abrogated by treatment with the autophagy inhibitors acadesine and chloroquine diphosphate. Silencing of MICALL2 resulted in a suppressive activity of Rac1 while suppressing Rac1 activation attenuated the pro-EGFR, pro-MMP9, and proinvasive effects induced by the overexpression of MICALL2. Collectively, our results indicated that MICALL2 participated in the process of immune infiltration and invasion by ovarian cancer cells. Moreover, MICALL2 prevented EGFR degradation in a Rac1-dependent manner, consequently leading to EGFR-AKT-mTOR-MMP9 signaling activation and invadopodia-mediated matrix degradation.

EMP3 sustains oncogenic EGFR/CDK2 signaling by restricting receptor degradation in glioblastoma

Epithelial membrane protein 3 (EMP3) is an N-glycosylated tetraspanin with a putative trafficking function. It is highly expressed in isocitrate dehydrogenase-wild-type glioblastoma (IDH-wt GBM), and its high expression correlates with poor survival. However, the exact trafficking role of EMP3 and how it promotes oncogenic signaling in GBM remain unclear. Here, we show that EMP3 promotes EGFR/CDK2 signaling by regulating the trafficking and enhancing the stability of EGFR. BioID2-based proximity labeling revealed that EMP3 interacts with endocytic proteins involved in the vesicular transport of EGFR. EMP3 knockout (KO) enhances epidermal growth factor (EGF)-induced shuttling of EGFR into RAB7 + late endosomes, thereby promoting EGFR degradation. Increased EGFR degradation is rescued by the RAB7 negative regulator and novel EMP3 interactor TBC1D5. Phosphoproteomic and transcriptomic analyses further showed that EMP3 KO converges into the inhibition of the cyclin-dependent kinase CDK2 and the repression of EGFR-dependent and cell cycle transcriptional programs. Phenotypically, EMP3 KO cells exhibit reduced proliferation rates, blunted mitogenic response to EGF, and increased sensitivity to the pan-kinase inhibitor staurosporine and the EGFR inhibitor osimertinib. Furthermore, EGFR-dependent patient-derived glioblastoma stem cells display a transcriptomic signature consistent with reduced CDK2 activity, as well as increased susceptibility to CDK2 inhibition upon EMP3 knockdown. Lastly, using TCGA data, we showed that GBM tumors with high EMP3 expression have increased total and phosphorylated EGFR levels. Collectively, our findings demonstrate a novel EMP3-dependent mechanism by which EGFR/CDK2 activity is sustained in GBM. Consequently, EMP3’s stabilizing effect provides an additional layer of tumor cell resistance against targeted kinase inhibition.

Impact of diet modification on body mass and kidney function in patients with diabetic nephropathy: a pilot study.

The increasing trend in chronic kidney disease (CKD) has occurred in parallel with the increased prevalence of obesity and diabetes type 2. The relationship between a reduction in body mass and protein intake in diabetic nephropathy (DN) has not been adequately understood. This study aimed to determine whether dietary intervention in an adult with DN is associated with decreasing proteinuria or changes in kidney function over six months. The study included 120 patients with DN, consecutively admitted to a dietitian from a Kidney Disease Clinic. Patients were classified into two groups: a reduction diet or a normal calorie diet, both with 0.8 g of protein/kg of ideal body weight/day. Anthropometric and laboratory assessments were done before and after observation. After six months, in the study group of patients on a reducing diet, a decrease in body mass, body mass index (BMI) and stabilization of estimated glomerular filtration rate (eGFR) were observed. There was also a significant correlation between the time of diabetes diagnosis and eGFR and creatinine (R Spearman=-0.24 and 0.3, respectively; p=0.05). There were no other significant associations between body mass, BMI, albuminuria, eGFR, or creatinine. The study shows that obesity is a common comorbid disease in patients with DN and that dietary intervention is associated with a significant reduction in body mass and stabilization of eGFR in these patients.

Abstract P5-02-41: UBE2E3 promotes the progression of HER2-positive breast cancer and influences the efficacy of targeted therapy via EGFR stabilization

Abstract Background: In the past 20 years, the efficacy and prognosis of HER2-positive breast cancer have significantly improved. However, nearly 50% of patients still have residual invasive tumors after chemotherapy combined with dual-targeted neoadjuvant therapy, especially for those with disease progression during treatment. A lack of effective therapeutic regimens results from the failure of targeted therapy, whose heterogeneity is especially worthy of our attention. The aim of this study was to look for efficacy markers and investigate new drug-resistance mechanisms. Methods: Firstly, the high-throughput sequencing data from 81 patients who received neoadjuvant chemotherapy TCbH (paclitaxel + carboplatin + trastuzumab) was analyzed by the efficacy outcomes. They were divided into 8 patients with stable or progressive disease (SD/PD), 35 with partial response (PR), and 38 with pathological complete remission (pCR). Then, UBE2E3 was chosen from the different expression genes between SD/PD and pCR based on efficacy results and the weighted gene co-expression network (WGCNA). UBE2E3 clinical correlations were investigated using publicly available data from The Cancer Genome Atlas (TCGA) and the Molecular Taxonomy of Breast Cancer International Consortium (METABRIC), and UBE2E3 was validated using immunohistochemistry (IHC) on 200 HER2-positive breast cancer tissue chips. Further, the UBE2E3 knockdown and overexpression stable transfer cell lines were constructed, and the effects of UBE2E3 on cell proliferation, clone formation, and drug sensitivity were verified by live cell imaging, the CCK8 assay, plate cloning, and IC50 assays, respectively. The tumor growth of UBE2E3 in vivo was investigated by an in situ transplantation tumor assay in nude mice. Meanwhile, the p-RB assay of mouse tissues by IHC was used to explore the effect of UBE2E3 on cell proliferation. RNA-seq was used to screen the downstream molecules of UBE2E3. Western blotting was used to verify the results of bioinformatics analysis and to explore the downstream key molecules. The protease inhibitor MG132 and actinomycin CHX were used to look at the effect on the stability of the target protein. Immunoprecipitation and silver staining assays were used to find interacting proteins with the UBE2E3. Results: Ten hub-genes which were efficacy-related were identified by WGCNA analysis, in which UBE2E3 was highly expressed in the SD/PD group (p < 0.05). In HER2-positive breast cancer, high expression of UBE2E3 was associated with poor prognosis and decreased disease-free survival both in public data and Fudan University Shanghai Cancer Center (FUSCC) data [HR 2. 36, (1.25–4.47), p < 0.05]. The experimental results demonstrated that UBE2E3 promoted the proliferation of HER2-positive breast cancer cells, enhanced clone formation, and resisted lapatinib’s treatment in cellular phenotype; and that UBE2E3 promoted tumor growth in vivo and upregulated the expression of p-RB. The differentially expressed genes’ sets of the RNA-seq between overexpressed cell lines and control showed that overexpressing UBE2E3 activated the EGFR pathway. Further, an immunoblot assay confirmed that UBE2E3 positively regulated EGFR levels and activated the downstream MAPK pathway. The proteasome inhibitor MG132 and CHX assays showed that UBE2E3 could stabilize EGFR proteins. The co-immunoprecipitation and silver staining assays showed that UBE2E3 stabilized EGFR proteins by interacting with c-Cbl. Conclusion: UBE2E3 could negatively affect the efficacy of HER2-positive breast cancer therapy and is significantly associated with poor prognosis. UBE2E3 may serve as a potential marker of efficacy and prognosis for HER2-positive breast cancer in the future. Therapeutic efficacy is affected by UBE2E3, which binds to c-Cbl and causes upregulation of EGFR expression in vivo, which in turn causes the MAPK pathway to be activated and tumor growth to be pushed up. Citation Format: Pei Li, Wei-Ru Chi, Bingqiu Xiu, Qi Zhang, Liyi Zhang, Ming Chen, Jingyan Xue, Xiaoyan Huang, Yayun Chi, Jiong Wu. UBE2E3 promotes the progression of HER2-positive breast cancer and influences the efficacy of targeted therapy via EGFR stabilization [abstract]. In: Proceedings of the 2022 San Antonio Breast Cancer Symposium; 2022 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2023;83(5 Suppl):Abstract nr P5-02-41.

PELI1 and EGFR cooperate to promote breast cancer metastasis

Pellino-1 (PELI1) is an E3 ubiquitin ligase acting as a key regulator for the inflammation and autoimmunity via the ubiquitination of the substrate proteins. There is increasing evidence to support that PELI1 functions as an oncoprotein in tumorigenesis and metastasis. However, the molecular mechanism underlying the high expression and oncogenic roles of PELI1 in cancers remains limited. Herein, we revealed a novel regulation mechanism by which PELI1 and EGFR cooperate to promote breast cancer metastasis. EGFR is positively correlated with PELI1 expression in breast cancers, and its activation led to the phosphorylation of PELI1 at Tyr154 and Thr264, which subsequently activated its E3 ubiquitin ligase. Simultaneously, PELI1 physically interacted with and enhanced the stability of EGFR via the K63-linked polyubiquitination in reverse. The co-inhibition of the PELI1-EGFR showed synergetic effect to repress breast cancer metastasis. Furthermore, we identified a compound S62 as a small molecule disruptor of PELI1/EGFR that effectively repressed breast cancer metastasis. Our study not only uncovered the emerging roles of PELI1/EGFR interaction in the progression of breast cancer, but also provided an effective strategy for the inhibition of metastasis in breast cancer.

Eculizumab Rescue Therapy in Patients With Recurrent Atypical Hemolytic Uremic Syndrome After Kidney Transplantation

Since 2016, kidney transplantation in patients with atypical hemolytic uremic syndrome (aHUS) in the Netherlands is performed without eculizumab prophylaxis. Eculizumab is given in case of posttransplant aHUS recurrence. Eculizumab therapy is monitored in the CUREiHUS study. All participating kidney transplant patients who received eculizumab therapy for a suspected posttransplant aHUS recurrence were evaluated. Overall recurrence rate was monitored prospectively at Radboud University Medical Center. In the period from January 2016 until October 2020, we included 15 (12 females, 3 males; median age 42 years, range 24-66 years) patients with suspected aHUS recurrence after kidney transplantation in this study. The time interval to recurrence showed a bimodal distribution. Seven patients presented early after transplantation (median 3 months, range 0.3-8.8 months), with typical aHUS features: rapid loss of estimated glomerular filtration rate (eGFR) and laboratory signs of thrombotic microangiopathy (TMA). Eight patients presented late (median 46 months, range 18-69 months) after transplantation. Of these, only 3 patients had systemic TMA, whereas 5 patients presented with slowly deteriorating eGFR without systemic TMA. Treatment with eculizumab resulted in improvement or stabilization of eGFR in 14 patients. Eculizumab discontinuation was tried in 7 patients; however, it was successful only in 3. At the end of the follow-up (median 29 months, range 3-54 months after start of eculizumab), 6 patients had eGFR<30 ml/min per 1.73 m2. Graft loss had occurred in 3 of them. Overall, aHUS recurrence rate without eculizumab prophylaxis was 23%. Rescue treatment of posttransplant aHUS recurrence is effective; however, some patients suffer from irreversible loss of kidney function, likely caused by delayed diagnosis and treatment and/or too aggressive discontinuation of eculizumab. Physicians should be aware that recurrence of aHUS can present without evidence of systemic TMA.

Development of trisubstituted thiophene-3-arboxamide selenide derivatives as novel EGFR kinase inhibitors with cytotoxic activity.

Overexpression of EGFR is one of the eminent oncogenic drivers detected in the development of several human cancers. The increasing incidences of mutation-based resistance in the tyrosine kinase domain call upon the need for the development of a newer class of small-molecule TK inhibitors. Accordingly, a new series of symmetrical trisubstituted thiophene-3-carboxamide selenide derivatives was developed via the hybridization of complementary pharmacophores. Most of the compounds showed a modest to excellent antiproliferative action at 20 μM concentration. The utmost antiproliferative activity was portrayed by compound 16e on the selected cancer cell lines with IC50 < 9 μM, the lowest being 3.20 ± 0.12 μM in the HCT116 cell line. Further, it also displayed an impressive EGFR kinase inhibition with an IC50 value of 94.44 ± 2.22 nM concentration. As a corollary of the reported EGFR inhibition, the nature, energy, and stability of the binding interactions were contemplated via in silico studies.

Periostin promotes EMT via inhibition of RIN1-mediated endocytosis of EGFR in gliomas

PurposeApproximately 1/3 of brain tumors are gliomas. Previous glioma-related studies have reported increased expression of periostin (POSTN) in these cancerous tissues, but the role and mechanism of POSTN in glioma development remain unclear.MethodsNanoscale liquid chromatography coupled with tandem mass spectrometry (nano LC–MS/MS) and RNA sequencing were used to identify differential protein and mRNA expression in clinical glioma samples. Quantitative real-time PCR (qRT–PCR) was used to measure the expression of POSTN in tissues and cells. The effects of POSTN on glioma cell migration and invasion were examined using wound healing, Transwell, and three-dimensional spheroid assays in vitro and a nude mouse xenograft model in vivo. The effects of POSTN on the stability, endocytosis, and degradation of EGFR were examined by immunoblotting and immunofluorescence staining. Truncation mutation analysis was performed to investigate direct interactions between POSTN and EGFR. Immunohistochemical staining was carried out to confirm the clinical significance of POSTN.ResultsOverexpression of POSTN induced epithelial-to-mesenchymal transition (EMT) in glioma cells in vivo and in vitro. Mechanistically, POSTN downregulation inhibited EGFR signaling by promoting EGFR endocytosis and degradation. In addition, POSTN was found to bind to EGFR and RIN1, inhibiting EGFR endocytosis and degradation and thus activating the PI3K-Akt signaling pathway.ConclusionThese findings indicate the mechanism by which the POSTN/EGFR/RIN1 axis inhibits EGFR endocytosis and degradation, resulting in glioma cell EMT through the PI3K-AKT signaling pathway. Targeting POSTN/EGFR/RIN1 interactions may guarantee beneficial outcomes of glioma treatment.

LZTR1 Mutation Mediates Oncogenesis through Stabilization of EGFR and AXL.

EGFR and AXL are substrates of LZTR1-CUL3 ubiquitin ligase. The frequent somatic and germline mutations of LZTR1 in human cancer cause EGFR and AXL accumulation and deregulated signaling. LZTR1-mutant tumors show vulnerability to concurrent inhibition of EGFR and AXL, thus providing precision targeting to patients affected by LZTR1-mutant cancer. This article is highlighted in the In This Issue feature, p. 517.

Cancer regulator EGFR-ErbB4 heterodimer is stabilized through glycans at the dimeric interface.

EGFR and ErbB4 are the only two members of cancer-regulating ErbB RTKs that maintain the activation of their extracellular ligand-binding domain and intracellular tyrosine kinase domain. EGFR and ErbB4 could form homo and heterodimers upon their activation. Heterodimerization triggers more diverse intracellular pathways compared to homodimerization. Moreover, it is known that N-glycosylation is crucial for the stabilization and activation of EGFR and ErbB4 receptors. Herein, atomistic molecular dynamics were simulated to study the EGFR-ErbB4 heterodimer in the glycosylated and unglycosylated states. It was shown that the EGFR-ErbB4 heterodimer is highly stabilized by glycosylation. The increased stability is most significant at the dimeric interfaces, regulated by packing of three glycans attached to EGFR (Asn337) and ErbB4 (Asn333, Asn523) at the dimeric interface. Finally, it is proposed that heterodimerization is the persistent key player in the EGFR and ErbB4 activation. Thus, targeting the heterodimers in future therapeutic designs could be a promising approach against drug resistance to ErbB-positive cancers.

PUF60 promotes glioblastoma progression through regulation of EGFR stability

PUF60 (Poly (U) binding splicing factor 60 kDa), a nucleic acid-binding protein, has been shown to regulate transcription and links to tumorigenesis in various cancers. However, its biological role and function in glioblastoma remain unknown. In this study, we found that PUF60 is highly expressed in glioblastoma and correlated with poor prognosis. Furthermore, PUF60 knockdown significantly decreased the proliferation of glioblastoma cells in vitro and in vivo. Mechanistically, PUF60 could reduce the ubiquitination level of EGFR by transcriptionally regulating STUB1, an E3 ubiquitin ligase of EGFR, which lead to the activation of the EGFR-AKT pathway. Collectively, our study reveals the oncogenic role of PUF60 in glioblastoma and provides a potential therapeutic target for glioblastoma treatment.