Aberrant Pathways Research Articles

Dietary sodium modulates mTORC1-dependent trained immunity in macrophages to accelerate CKD development

Chronic Kidney Disease (CKD) is a significant global health issue linked to dietary habits, especially high salt intake. However, the precise mechanisms driving this progression remain incompletely understood. This study reveals that a high-salt diet intensifies macrophage trained immunity, leading to a marked pro-inflammatory response upon repeated pathogenic exposures, as evidenced by increased renal damage and fibrosis. Under high-salt conditions, there was an induction of CD45+F4/80+ macrophage infiltration into the renal tissue, accompanied by heightened production of inflammatory cytokines. Distinct responses were observed between circulating and resident renal macrophages to a high-salt diet, with a notable upsurge in the migration of pro-inflammatory macrophages, driven by CCL2-CCR2 signaling and aberrant mTORC1 pathway activation. Treatment with rapamycin-liposome effectively reduced this inflammatory cascade by mitigating mTORC1 signaling. Transplantation of monocytes from CKD mice with a high-salt diet significantly exacerbates renal inflammatory damage in the host mice, showing increased migratory tendency and inflammatory activity. The cell co-culture experiment further confirmed that macrophages derived from CKD mice, particularly those under conditions of high salt exposure, significantly induced apoptosis and inflammatory responses in renal tubular cells. Taken together, recurrent exposure to LPS elicits the activation of trained immunity, consequently augmenting inflammatory response of monocytes/macrophages in the involved kidneys. The high-salt diet exacerbates this phenomenon, attributable at least in part to the overactivation of the mTORC1 pathway. This research emphasizes the importance of dietary modulation and targeted immunological interventions in slowing CKD progression, providing new insights into mTORC1-mediated pathophysiological mechanisms and potential management strategies for CKD.

Cholangiocyte ciliary defects induce sustained epidermal growth factor receptor signaling.

The primary cilium, an organelle that protrudes from cell surfaces, is essential for sensing extracellular signals. With disturbed cellular communication and chronic liver pathologies, this organelle's dysfunctions have been linked to disorders, including polycystic liver disease (PLD) and Cholangiocarcinoma (CCA). The goal of this study was to elucidate the relationship between primary cilia and the crucial regulator of cellular proliferation, the epidermal growth factor receptor (EGFR) signaling pathway, which has been associated with various clinical conditions. The study identified aberrant EGFR signaling pathways in cholangiocytes lacking functional primary cilia. Using liver-specific IFT88 knockout mice, a Pkhd1 mutant rat model, and human cell lines that didn't have functional cilia. Cilia-deficient cholangiocytes showed persistent EGFR activation because of impaired receptor degradation, in contrast to their normal counterparts, where EGFR localization to the cilia promotes appropriate signaling. Using HDAC6 inhibitors to restore primary cilia accelerates EGFR degradation, thereby reducing maladaptive signaling. Importantly, experimental intervention with the HDAC6 inhibitor tubastatin A in an orthotopic rat model moved EGFR to cilia and reduced ERK phosphorylation. Concurrent administration of EGFR and HDAC6 inhibitors in cholangiocarcinoma and polycystic liver disease cells demonstrated synergistic anti-proliferative effects, which were associated with the restoration of functioning primary cilia. This study's findings shed light on ciliary function and robust EGFR signaling with slower receptor turnover. We could use therapies that restore the function of primary cilia to treat EGFR-driven diseases in PLD and CCA.

Design and optimization of DPC-crosslinked HPβCD nanosponges for entrectinib oral delivery: formulation, characterization, and pharmacokinetic studies

BackgroundIn advanced or metastatic cancers characterized by specific genetic alterations, heightened growth and resistance to conventional therapies are common. Targeted treatments like entrectinib (ENT) precisely inhibit aberrant signaling pathways, potentially enhancing outcomes. The objective of this research is to develop and enhance the effectiveness of entrectinib-loaded nanosponge formulations by utilizing hydroxypropyl-β-cyclodextrin (HPβCD) to improve its oral bioavailability.ResultsThe study employed surface response methodology and Design-Expert® software to optimize key formulation variables such as the molar concentration ratio of the polymer and cross-linker, as well as process variables such as stirring speed and duration. Optimization focused on particle size, polydispersity index, and percentage entrapment efficiency. Validation methods encompassed Fourier transform spectroscopy (FTIR), differential scanning calorimetry (DSC), scanning electron microscopy (SEM), in vitro release studies, and in vivo studies.After optimization, ENT-loaded HPβCD NSPs were formulated with a molar ratio (P:CL) of 0.800 mg, stirred at 3000 rpm for 420 min, achieving a desirability of 0.926. Predicted values for PS (particle size), PdI (polydispersity index), and EE % (entrapment efficiency) were 146.98 nm, 0.263, and 88.29%, respectively. The optimized formulation showed a mean size of 151.8 ± 5.6 nm, PDI of 0.233 ± 0.049, and EE of 87.36 ± 1.61%. Further validation through various analyses confirmed the optimization's efficacy, with notable improvements demonstrated in AUC0-t (6.30-fold) and Cmax (4.10 times) compared to the free drug.ConclusionThe findings of the study indicated that nanosponges exhibit promise as an effective carrier for delivering entrectinib, addressing for advance tumor effectively by enhancing release and bioavailability in the treatment of cancer.

Fibrosis and Hepatocarcinogenesis: Role of Gene-Environment Interactions in Liver Disease Progression.

The liver is a complex organ that performs vital functions in the body. Despite its extraordinary regenerative capacity compared to other organs, exposure to chemical, infectious, metabolic and immunologic insults and toxins renders the liver vulnerable to inflammation, degeneration and fibrosis. Abnormal wound healing response mediated by aberrant signaling pathways causes chronic activation of hepatic stellate cells (HSCs) and excessive accumulation of extracellular matrix (ECM), leading to hepatic fibrosis and cirrhosis. Fibrosis plays a key role in liver carcinogenesis. Once thought to be irreversible, recent clinical studies show that hepatic fibrosis can be reversed, even in the advanced stage. Experimental evidence shows that removal of the insult or injury can inactivate HSCs and reduce the inflammatory response, eventually leading to activation of fibrolysis and degradation of ECM. Thus, it is critical to understand the role of gene-environment interactions in the context of liver fibrosis progression and regression in order to identify specific therapeutic targets for optimized treatment to induce fibrosis regression, prevent HCC development and, ultimately, improve the clinical outcome.

O-glycosylation of IgA1 and the pathogenesis of an autoimmune disease IgA nephropathy.

IgA nephropathy is a kidney disease characterized by deposition of immune complexes containing abnormally O-glycosylated IgA1 in the glomeruli. Specifically, some O-glycans are missing galactose that is normally β1,3-linked to N-acetylgalactosamine of the core 1 glycans. These galactose-deficient IgA1 glycoforms are produced by IgA1-secreting cells due to a dysregulated expression and activity of several glycosyltransferases. Galactose-deficient IgA1 in the circulation of patients with IgA nephropathy is bound by IgG autoantibodies and the resultant immune complexes can contain additional proteins, such as complement C3. These complexes, if not removed from the circulation, can enter the glomerular mesangium, activate the resident mesangial cells, and induce glomerular injury. In this review, we briefly summarize clinical and pathological features of IgA nephropathy, review normal and aberrant IgA1 O-glycosylation pathways, and discuss the origins and potential significance of natural anti-glycan antibodies, namely those recognizing N-acetylgalactosamine. We also discuss the features of autoantibodies specific for galactose-deficient IgA1 and the characteristics of pathogenic immune complexes containing IgA1 and IgG. In IgA nephropathy, kidneys are injured by IgA1-containing immune complexes as innocent bystanders. Most patients with IgA nephropathy progress to kidney failure and require dialysis or transplantation. Moreover, most patients after transplantation experience a recurrent disease. Thus, a better understanding of the pathogenetic mechanisms is needed to develop new disease-specific treatments.

Abstract Tu042: Fatty Acid Dysregulation Drives Cardio-Hepatic Crosstalk in Heart Failure with Preserved Ejection Fraction (HFpEF)

Introduction: Heart failure with preserved ejection fraction (HFpEF) is a heterogenous clinical syndrome that accounts for nearly half of all heart failure cases world-wide. The pathophysiological mechanisms underlying HFpEF include a variety of extracardiac abnormalities such as metabolic derangements, arterial hypertension, and microvascular endothelial dysfunction, that all drive left ventricular remodeling and dysfunction. The phenotypic diversity presented in HFpEF involves functional and structural changes in several organs including the liver. As a highly vascularized organ, the liver is highly sensitive to any hemodynamic changes in the heart and clinical studies have established the presence of liver injury in HFpEF patients. However, there is limited evidence of this relationship in preclinical mouse models, thereby hindering the exploration of the pathological mechanisms linking the two organs. Cardio-hepatic interactions are poorly understood yet play a critical role in the pathophysiology of HFpEF where aberrant metabolic signaling pathways such as insulin resistance, inflammation and oxidative stress significantly contribute to disease progression and further perpetuate a vicious cycle of cardio-hepatic deterioration. Hypothesis: With limited preclinical data in the field, we sought to elucidate the potential pathophysiological mechanisms driving cardio-hepatic crosstalk in HFpEF. Methods: We used a two-hit preclinical mouse model that recapitulates cardiometabolic HFpEF to characterize the coexistence of cardiac and hepatic dysfunction in HFpEF. Male mice were kept on the HFpEF model for 15 weeks and subjected to echocardiography, glucose tolerance tests, histopathology, and multi-omics analyses. Results: We report that markers of HFpEF severity such as diastolic dysfunction and left ventricular hypertrophy, significantly correlated with hepatic injury and dysfunction that exacerbated metabolic dysfunction-associated fatty liver disease (MAFLD) progression. Impaired energy substrate utilization due to fatty acid dysregulation was a major mechanism underlying cardio-hepatic crosstalk in HFpEF. Conclusion: Our findings highlight fatty acid metabolism as a potential target to mitigate inter-organ dysfunction in HFpEF, representing a promising opportunity to create new treatment paradigms and drive positive outcomes in HFpEF.

AB001. Development of tumour-targeted therapy for the treatment of adult and paediatric high-grade gliomas.

Brain cancer patients, especially those suffering from high-grade gliomas (HGGs) face a bleak future with very dismal long-term disease-free survival outcomes due to the limited treatment options currently available. Therefore, there is an unmet need for new therapeutic intervention that extends patients' progress-free survival and improves their quality of life. A significant hurdle is the inability of current chemotherapy agents to cross the blood-brain barrier (BBB). BBB acts as a protective shield that filters the blood to ensure nothing harmful makes it to the brain. This protection is usually good, but it becomes a problem if you want to deliver therapeutic cancer drugs through it. This barrier blocks 98% of drugs from entering the brain. Even the ones that cross BBB are unevenly distributed in the normal brain and tumour tissue, resulting in mediocre treatment and severe side effects. We are developing drug delivery systems that can cross the BBB and facilitate the specific accumulation of drugs in the tumour tissue. This will significantly improve the efficacy of anticancer drugs in treating various brain cancers and reduce systemic toxicity. Our group has explored and developed BBB crossing and tumour targeting near infra-red dyes, which can be covalently attached to Food and Drug Administration (FDA)-approved chemotherapy agents (drug-dye conjugates), thereby delivering it to the tumour tissue. We synthesized such drug-dye conjugates to target various aberrant pathways in HGG and tested these conjugates against patient-derived HGG cell lines. One such conjugate was tested on a mouse model of glioblastoma, an aggressive form of HGG, and shown to cross the BBB and specifically accumulate in tumour tissue, bringing forth tumour burden reduction. The results obtained from this work serve as proof of principle that enables tumour-specific drug delivery to treat HGG. This work also paves the way for treating other brain cancers and central nervous system (CNS) disorders like Parkinson's and Alzheimer's disease, for which no adequate therapy exists.

Renal cancer: signaling pathways and advances in targeted therapies.

Renal cancer is a highlyheterogeneous malignancy characterized by rising global incidence and mortalityrates. The complex interplay and dysregulation of multiple signaling pathways,including von Hippel-Lindau (VHL)/hypoxia-inducible factor (HIF), phosphoinositide 3-kinase (PI3K)/protein kinase B (AKT)/mammalian target of rapamycin (mTOR), Hippo-yes-associated protein (YAP), Wnt/ß-catenin, cyclic adenosine monophosphate (cAMP), and hepatocyte growth factor (HGF)/c-Met, contribute to theinitiation and progression of renal cancer. Although surgical resection is thestandard treatment for localized renal cancer, recurrence and metastasiscontinue to pose significant challenges. Advanced renal cancer is associatedwith a poor prognosis, and current therapies, such as targeted agents andimmunotherapies, have limitations. This review presents a comprehensiveoverview of the molecular mechanisms underlying aberrant signaling pathways inrenal cancer, emphasizing their intricate crosstalk and synergisticinteractions. We discuss recent advancements in targeted therapies, includingtyrosine kinase inhibitors, and immunotherapies, such as checkpoint inhibitors.Moreover, we underscore the importance of multiomics approaches and networkanalysis in elucidating the complex regulatory networks governing renal cancerpathogenesis. By integrating cutting-edge research and clinical insights, this review contributesto the development of innovative diagnostic and therapeutic strategies, whichhave the potential to improve risk stratification, precision medicine, andultimately, patient outcomes in renal cancer.

AB005. Development of tumour specific therapy for treatment of diffuse intrinsic pontine glioma (DIPG).

Diffuse intrinsic pontine glioma (DIPG), is an aggressive form of paediatric high-grade glioma (pHGG) that affects children below the age of 10 months. The survival period for a child suffering from DIPG has not changed in decades (approximately 10 months). This pattern is similar for most pHGG; even though the survival period is more extended, tumour recurrence and death are almost inevitable. This is primarily due to the presence of the blood-brain barrier (BBB), which blocks the entry of most therapeutics into the brain, and also due to tumour heterogeneity associated with central nervous system (CNS) tumours that blunt the efficacy of targeted therapy. The development of a meaningful cure for paediatric brain cancer hinges on discovering chemotherapy agents that (I) can cross the BBB; (II) accumulates explicitly in tumour tissues; and (III) can block pathways leading to the escape of cancer stem cells, promoting recurrence. This project aims to develop therapeutics that can cross the BBB, a significant hindrance to delivering medicines across the brain, and specifically target cancer cells without affecting normal brain cells. We will accomplish this by attaching novel dyes possessing tumour specificity to various classes of chemotherapy agents. The compounds will be tested on patient-derived paediatric brain cancer cell lines and the most potent compounds will be progressed to an animal model of DIPG. Several drug-dye conjugates were designed and synthesized to target various aberrant pathways involved in disease initiation and progression of DIPG. These were tested first in patient-derived DIPG cell lines. Several of these drug-dye conjugates showed potent antiproliferative effect in various DIPG cell lines. One of these conjugates is currently undergoing maximum tolerated dose study in an animal model of DIPG. The present work details an effort to develop BBB crossing tumour specific therapeutic agents for the treatment of DIPG. The work has resulted in several promising drug-dye conjugates showing antiproliferative activity in various patient-derived DIPG cell lines, enabling the progression of such conjugates into animal models of DIPG. Such studies will inform the utility of such drug-dye conjugates for application in difficult to treat pHGGs such as DIPG.

Molecular developments in parasellar tumors and potential therapeutic implications.

The parasellar region is the anatomical area around the sella turcica that represents a crucial crossroad for important adjacent structures. Several distinct tumors can primarily originate from this area, the most common being meningiomas, gliomas, embryonal cell tumors, germ cell tumors and craniopharyngiomas. In addition, a number of systemic and inflammatory disorders can also affect the parasellar region most commonly involving the pituitary. These lesions have different pathology characteristics and malignant potential according to the new WHO CNS5 2021 classification. Signs and symptoms may be non-specific and are mostly related to a mass effect on the surrounding anatomical structures and/or impairment of endocrine function whereas the vast majority lack a secretory component. The mutational signature analysis based on advances in molecular techniques, has recently enabled the identification of specific gene mutations or signalling pathway aberrations. These developments may serve as a powerful mean to delineate the pathophysiology of these lesions and serve as a diagnostic, prognostic and therapeutic tool, particularly for high-risk populations. Treatment options include surgery alone or in combination with radiotherapy, chemotherapy and disease-specific medical therapy in order to prevent recurrence or further tumor growth along with replacement of coexistent pituitary hormonal deficiencies. In this comprehensive review, we present current state-of-the-art developments in the histopathology and molecular biology of these lesions that may be utilized by a dedicated multidisciplinary team of relevant specialties for the diagnosis, monitoring and treatment of the parasellar lesions that often represent a diagnostic and therapeutic challenge.

The pudendal syndrome: A photo essay of nerve compression damage visualized at neurolysis in patients with chronic neuropathic pelvic pain.

(1) To use intraoperative photographs to visualize and explain pudendal nerve compressions and anatomical variations of compression sites in patients with chronic pelvic pain. (2) To emphasize the diagnostic importance of sensory examination with a safety pin at the six pudendal nerve branches in all patients with chronic pelvic pain; the dorsal nerves (penis or clitoris; the perineal nerves; and the inferior rectal nerves). Between 2003 and 2014, "definite" pudendal neuropathy was diagnosed by examination and with two neurophysiologic tests. Neurolysis, via a transgluteal approach, was recommended only after 14 weeks of conservative care failed to adequately improve symptoms and validated symptom scores. Photographs of surgical findings were culled for their educational impact. An illustration of each photo clarifies the surgical anatomy. The transgluteal incision permits access to pudendal anatomy and compression sites from the subpiriformis area through the interligamentary space and the pudendal canal (Alcock canal). Compressions were acquired or congenital and severity varied significantly. Pinprick sensory testing diagnoses pudendal neuropathy in 92% of both genders. Mid-nerve compression occurred commonly between the sacrotuberous and sacrospinous ligaments less frequently in the Alcock canal, but also at aberrant pathways, for example, between layers of the sacrotuberous ligament; a separate inferior rectal nerve passing through the sacrospinous ligament; at an anomalous lateral pathway posterior to the ischial spine. The results of international surgeons are discussed. Decompression surgery was recommended in approximately 35% of patients in this practice, when pudendal neuropathy (pudendal syndrome), did not respond to two conservative levels of treatment: (1) nerve protection and medications and, (2) a series of three pudendal nerve perineural injections given at 4-week intervals. Significant nerve compression is consistently observed. Pathophysiology includes axonopathy from ischemia and demyelination. Neuropathy is readily diagnosed using a pinprick sensory examination of six pudendal nerve branches. Monitoring with the National Institutes of Health Chronic Prostatitis Symptom Index records cures >13 years.

Correlation of PD-L1 expression with CD8+ T cells and oxidative stress-related molecules NRF2 and NQO1 in esophageal squamous cell carcinoma.

Oxidative stress and the immune microenvironment both contribute to the pathogenesis of esophageal squamous cell carcinoma (ESCC). However, their interrelationships remain poorly understood. We aimed to examine the status of key molecules involved in oxidative stress and the immune microenvironment, as well as their relationships with each other and with clinicopathological features and prognosis in ESCC. The expression of programmed death-ligand 1 (PD-L1), CD8, nuclear factor erythroid-2 related factor-2 (NRF2), and NAD(P)H quinone oxidoreductase 1 (NQO1) was detected using immunohistochemistry in tissue samples from 176 patients with ESCC. We employed both combined positive score (CPS) and tumor proportion score (TPS) to evaluate PD-L1 expression and found a positive correlation between CPS and TPS. Notably, PD-L1 expression, as assessed by either CPS or TPS, was positively correlated with both NRF2 nuclear score and NQO1 score in stage II-IV ESCC. We also observed a positive correlation between the density of CD8+ T cells and PD-L1 expression. Furthermore, high levels of PD-L1 CPS, but not TPS, were associated with advanced TNM stage and lymph node metastases. Moreover, both PD-L1 CPS and the nuclear expression of NRF2 were found to be predictive of shorter overall survival in stage II-IV ESCC. By using the Mandard-tumor regression grading (TRG) system to evaluate the pathological response of tumors to neoadjuvant chemotherapy (NACT), we found that the TRG-5 group had higher NRF2 nuclear score, PD-L1 CPS, and TPS in pre-NACT biopsy samples compared with the TRG-3 + 4 group. The NQO1 scores of post-NACT surgical specimens were significantly higher in the TRG-5 group than in the TRG 3 + 4 group. In conclusion, the expression of PD-L1 is associated with aberrant NRF2 signaling pathway, advanced TNM stage, lymph node metastases, and unfavorable prognosis. The dysregulation of PD-L1 and aberrant activation of the NRF2 signaling pathway are implicated in resistance to NACT. Our findings shed light on the complex interrelationships between oxidative stress and the immune microenvironment in ESCC, which may have implications for personalized therapies and improved patient outcomes.

Follicular Fluid and Blood Monitorization of Infertility Biomarkers in Women with Endometriosis.

Infertility is recognized globally as a social disease and a growing medical condition, posing a significant challenge to modern reproductive health. Endometriosis, the third-most frequent gynecologic disorder, is one of the most common and intricate conditions that can lead to female infertility. Despite extensive research, the etiology, malignant transformation, and biological therapy of endometriosis remain unknown. Blood and follicular fluid are two matrices that have been carefully studied and can provide insights into women's health. These matrices are clinically significant because they contain metabolites closely associated with women's illness stage and reproductive outcomes. Nowadays, the application of metabolomic analysis in biological matrices may be able to predict the outcome of assisted reproductive technologies with greater precision. From a molecular viewpoint on reproductive health, we evaluate and compare the utilization of human follicular fluid and blood as matrices in analysis for diagnostic and assisted reproductive technology (ART) predictors of success for endometriosis patients. In the follicular fluid (FF), plasma, and serum of endometriosis-affected women, researchers identified dysregulations of oxidative stress, upregulation of several immune factors, and aberrations in energy metabolic pathways. The altered signatures negatively correlate with the overall oocyte and embryo quality and fertilization rate.

Chrysin targets aberrant molecular signatures and pathways in carcinogenesis (Review)

Chrysin targets aberrant molecular signatures and pathways in carcinogenesis (Review)

Comprehensive Review of Uterine Leiomyosarcoma: Pathogenesis, Diagnosis, Prognosis, and Targeted Therapy.

Uterine leiomyosarcoma (uLMS) is the most common subtype of uterine sarcomas. They have a poor prognosis with high rates of recurrence and metastasis. The five-year survival for uLMS patients is between 25 and 76%, with survival rates approaching 10-15% for patients with metastatic disease at the initial diagnosis. Accumulating evidence suggests that several biological pathways are involved in uLMS pathogenesis. Notably, drugs that block abnormal functions of these pathways remarkably improve survival in uLMS patients. However, due to chemotherapy resistance, there remains a need for novel drugs that can target these pathways effectively. In this review article, we provide an overview of the recent progress in ascertaining the biological functions and regulatory mechanisms in uLMS from the perspective of aberrant biological pathways, including DNA repair, immune checkpoint blockade, protein kinase and intracellular signaling pathways, and the hedgehog pathway. We review the emerging role of epigenetics and epitranscriptome in the pathogenesis of uLMS. In addition, we discuss serum markers, artificial intelligence (AI) combined with machine learning, shear wave elastography, current management and medical treatment options, and ongoing clinical trials for patients with uLMS. Comprehensive, integrated, and deeper insights into the pathobiology and underlying molecular mechanisms of uLMS will help develop novel strategies to treat patients with this aggressive tumor.

Characterization of Wnt Signaling Pathway Aberrations in Metastatic Prostate Cancer.

Wnt (wingless-type) signaling pathway (WSP) alterations have been identified in patients with prostate cancer and are implicated in disease progression and hormonal resistance. In this study, we utilized a multi-institutional dataset to characterize molecular alterations in the canonical and noncanonical WSPs in prostate cancer. Patients with prostate cancer who underwent tissue-based genomic sequencing were investigated. Tumors with somatic activating mutations in CTNNB1 or RSPO2 or inactivating mutations in either APC or RNF43 were characterized as having aberrant canonical Wnt signaling (WSP-activated). Overall survival analyses were restricted to microsatellite-stable (MSS) tumors lacking RNF43 G659fs* mutations. We also investigated noncanonical WSP by evaluation of ROR1, ROR2, and WNT5 in WSP-activated versus WSP wild-type (WSP-WT) tumors. Of 4,138 prostate cancer samples, 3,684 were MSS. Among MSS tumors, 42.4% were from metastatic sites, of which 19.1% were WSP activated, and 57.6% were from the prostate, of which 10.1% were WSP activated. WSP-activated tumors were more prevalent in metastatic sites than in primary prostate cancer. WSP-activated prostate cancer exhibited more SPOP mutations and higher expression of canonical WSP activators than WSP-WT tumors. ROR1 gene expression was elevated in WSP-activated tumors from both primary and metastatic sites. M2 macrophages predominated the tumor microenvironment in WSP-activated tumors. There was no significant difference in overall survival between patients with WSP-activated and WSP-WT prostate cancer. WSP-activated prostate cancer demonstrated a more immunosuppressed tumor microenvironment and a pronounced upregulation of ROR1 gene expression, underscoring its potential involvement in the crosstalk between canonical and noncanonical WSPs. Implications: Our findings may provide a rationale for developing novel therapeutic strategies targeting Wnt-activated prostate cancer.

Recurrent Glioblastoma-Molecular Underpinnings and Evolving Treatment Paradigms.

Glioblastoma is the most common and lethal central nervous system malignancy with a median survival after progression of only 6-9 months. Major biochemical mechanisms implicated in glioblastoma recurrence include aberrant molecular pathways, a recurrence-inducing tumor microenvironment, and epigenetic modifications. Contemporary standard-of-care (surgery, radiation, chemotherapy, and tumor treating fields) helps to control the primary tumor but rarely prevents relapse. Cytoreductive treatment such as surgery has shown benefits in recurrent glioblastoma; however, its use remains controversial. Several innovative treatments are emerging for recurrent glioblastoma, including checkpoint inhibitors, chimeric antigen receptor T cell therapy, oncolytic virotherapy, nanoparticle delivery, laser interstitial thermal therapy, and photodynamic therapy. This review seeks to provide readers with an overview of (1) recent discoveries in the molecular basis of recurrence; (2) the role of surgery in treating recurrence; and (3) novel treatment paradigms emerging for recurrent glioblastoma.

Reciprocal regulation between RACGAP1 and AR contributes to endocrine therapy resistance in prostate cancer

BackgroundEndocrine resistance driven by sustained activation of androgen receptor (AR) signaling pathway in advanced prostate cancer (PCa) is fatal. Characterization of mechanisms underlying aberrant AR pathway activation to search for potential therapeutic strategy is particularly important. Rac GTPase-activating protein 1 (RACGAP1) is one of the specific GTPase-activating proteins. As a novel tumor proto-oncogene, overexpression of RACGAP1 was related to the occurrence of various tumors.MethodsBioinformatics methods were used to analyze the relationship of expression level between RACGAP1 and AR as well as AR pathway activation. qRT-PCR and western blotting assays were performed to assess the expression of AR/AR-V7 and RACGAP1 in PCa cells. Immunoprecipitation and immunofluorescence experiments were conducted to detect the interaction and co-localization between RACGAP1 and AR/AR-V7. Gain- and loss-of-function analyses were conducted to investigate the biological roles of RACGAP1 in PCa cells, using MTS and colony formation assays. In vivo experiments were conducted to evaluate the effect of RACGAP1 inhibition on the tumor growth.ResultsRACGAP1 was a gene activated by AR, which was markedly upregulated in PCa patients with CRPC and enzalutamide resistance. AR transcriptionally activated RACGAP1 expression by binding to its promoter region. Reciprocally, nuclear RACGAP1 bound to the N-terminal domain (NTD) of both AR and AR-V7, blocking their interaction with the E3 ubiquitin ligase MDM2. Consequently, this prevented the degradation of AR/AR-V7 in a ubiquitin-proteasome-dependent pathway. Notably, the positive feedback loop between RACGAP1 and AR/AR-V7 contributed to endocrine therapy resistance of CRPC. Combination of enzalutamide and in vivo cholesterol-conjugated RIG-I siRNA drugs targeting RACGAP1 induced potent inhibition of xenograft tumor growth of PCa.ConclusionIn summary, our results reveal that reciprocal regulation between RACGAP1 and AR/AR-V7 contributes to the endocrine resistance in PCa. These findings highlight the therapeutic potential of combined RACGAP1 inhibition and enzalutamide in treatment of advanced PCa.

LGG-51. SYSTEMIC IMMUNE TOXICITY OF BRAF AND MEK-INHIBITORS IN CHILDREN: A PAN-CANADIAN SERIES

Abstract BACKGROUND BRAF/MEK-inhibitors have been transformative for pediatric gliomas with RAS/MAPK pathway aberrations. The RAS/MAPK pathway has a complex role in immune regulation. Though well-known in adults, the systemic immune-related adverse effects (irAE) of BRAF/MEKi in children are not widely reported. METHODS We performed a retrospective chart review for irAE following BRAF/MEKi in children treated at SickKids between 2016-2023. Additional patients were included through a pan-Canadian survey. RESULTS 136 patients on BRAF/MEKi were included (MEKi: 74%, BRAFi: 13%, BRAF+MEKi: 13%); irAE was reported in 6/136 (4.5%). One additional patient was included through the national survey. Median age was 14 years (range: 7-16). Male:female was 3:4. Three patients were on BRAFi, and two each on MEKi, and BRAF+MEKi. Early events developing within weeks of drug initiation included hyper-immune systemic inflammatory responses in three children on BRAFi and one child on MEKi. There was no evidence of any concomitant infection. Two children needed intensive care and showed evidence of multi-organ dysfunction. Delayed irAE developing after months to years on therapy included multi-systemic sarcoid-like reaction, parasympathetic dysautonomia (both on BRAF+MEKi) and brachial neuritis/Parsonage-Turner syndrome (MEKi). Management included drug holidays, dose reductions, and immunosuppressive treatment with steroids. Long-term steroids were needed in two of these seven patients. CONCLUSIONS Pediatric oncologists need to be aware of rare yet possibly under-reported systemic immune toxicity in children treated with BRAF/MEKi. They can present acutely, or while on chronic therapy. Management may be challenging in view of issues with rebound tumor growth on stopping some of these drugs, with select patients needing concomitant, long-term immunosuppressive therapy. Genetic susceptibility and biomarkers may need to be systematically studied in future clinical trials of novel RAS/MAPK inhibitors. Continued surveillance and reporting are needed for the marketed compounds, especially for children on long-term use of these inhibitors.

What is a bad ALK? A scoping review of molecular markers of poor prognosis.

e20530 Background: Patients with non-small cell lung cancer (NSCLC) with anaplastic lymphoma kinase ( ALK) rearrangements derive a significant and durable clinical benefit from tyrosine kinase inhibitors (TKI). However, a portion of patients have progressive disease as their best response and progress to death much earlier than expected which is termed primary resistance. This scoping review aims to summarize the known molecular mechanisms that underlie this lethal ALK phenotype. Methods: We performed a systematic scoping review from scientific databases such as Ovid Medline, Ovid Embase, and Cochrane Central Register of Controlled Trials. Data was extracted from the database inception to March 13, 2023. Studies included molecular markers of poor prognosis, with a focus on TP53, variant 3 re-arrangements, and reports of poor clinical response to TKIs (defined as progression-free survival less than 3 months on 1st line TKI or overall survival less than 2 years from exposure to 1st line TKI). 2nd generation and 3rd generation ALK TKI clinical trial data were also included. Results: A total of 4360 studies were screened and 136 studies were included. Numerous studies implicated the negative prognostic role of variant 3 likely mediated through the acquisition of on-target resistance mutations compared to other variants. TP53 mutations were also associated with a worse prognosis and implicated with greater chromosomal instability and mutational burden. Furthermore, reports of both variant 3 and TP53 mutations together were associated with even worse survival suggesting both molecular mechanisms combined can confer primary resistance phenotype. Other mediators of primary resistance included aberrations in cell cycle regulators such as CDKN2A/B loss, mutations in cell signalling pathways such as the PI3K/ AKT/mTOR pathway, deficiencies in DNA repair mechanisms, and uncommon fusion partners. Consistent with these prior studies, comprehensive genomic analysis from clinical trial data of 2nd generation and 3rd generation TKIs was unable to identify a singular genomic signature that underlies this lethal phenotype. However, a general trend from the literature suggested that the combination of multiple aberrations is likely necessary to confer a primary resistance phenotype, though the relative contribution of each somatic mutation likely will vary. Conclusions: This scoping review highlights that in NSCLC, the lethal ALK phenotype is likely composed of a heterogeneous population of various combinations of poor prognostic factors including variant 3, mutations in cell cycle regulators and other aberrations in cell signalling pathways. There remains an unmet need for a genomic assay to integrate all these various molecular markers to predict the lethal ALK phenotype.