Genetics-guided therapy in neuroendocrine carcinoma: response to BRAF- and MEK-inhibitors.

Background: Metastatic neuroendocrine carcinoma (NEC) is associated with short survival. Other than platinum-based chemotherapy, there is no clear standard regimen. Current guidelines suggest that combination treatment with BRAF-inhibitors should be considered for patients with BRAF V600E-mutated NEC. However, since only eight such patients have been reported in the literature, our object was to confirm the validity of this recommendation. Methods: This was a single-center retrospective cohort study conducted at Uppsala University Hospital. The included patients 1) had a histopathologically confirmed diagnosis of NEC, 2) were diagnosed between January 1st, 2018 and December 31st, 2023, 3) had tumor tissue genetically screened by a broad next-generation sequencing (NGS) panel, and 4) showed a tumor mutation for which there is a currently available targeted therapy. Results: We screened 48 patients diagnosed with NEC between January 1st, 2018 and December 31st, 2023. Twelve had been analyzed with a broad NGS-panel, and two had a targetable mutation. Both these patients harbored a BRAF V600E-mutated colon-NEC and were treated with BRAF- and MEK-inhibitors dabrafenib and trametinib in second-line. At first radiological evaluation (RECIST 1.1), both patients had a reduction of tumor size, which decreased by 31 and 40%. Both had short response periods, and their overall survival was 12 and 9 months. Conclusions: BRAF-mutated NEC is sensitive to treatment with BRAF- and MEK-inhibitor combination. These results further support that DNA sequencing should be considered as standard of care in NECs to screen for potential treatment targets.

Dabrafenib for Pilocytic Astrocytoma With BRAF V599ins.

This report highlights the first pediatric case of pilocytic astrocytoma with BRAF V599ins mutation, successfully treated with dabrafenib.

Large-vessel vasculitis possibly induced by BRAF and MEK inhibitors for BRAF V600E positive lung adenocarcinoma.

The combination therapy of v-Raf murine sarcoma viral oncogene homolog B1 (BRAF) and mitogen-activated protein kinase kinase (MEK) inhibitors is approved for treating patients with BRAF V600E-positive tumours, including melanoma and lung cancer. Several case reports indicated autoimmune side effects associated with the use of BRAF and MEK inhibitors. Still, the effects of these drugs on the immune system were not fully elucidated. Here, we report a patient with large-vessel vasculitis diagnosed after initiation of treatment with dabrafenib and trametinib for BRAF V600E-positive metastatic lung adenocarcinoma. She was a never-smoker woman in her early 70s who presented with a chronic cough and was diagnosed with BRAF V600E-positive metastatic lung adenocarcinoma by transbronchial lung biopsy. She was successfully treated with prednisolone and methotrexate while BRAF and MEK inhibitors were continued. We should be careful about autoimmune diseases using BRAF and MEK inhibitors.

The risk associated with organophosphorus nerve agents: from their discovery to their unavoidable threat, current medical countermeasures and perspectives.

The first organophosphorus nerve agent was discovered accidently during the development of pesticides, shortly after the first use of chemical weapons (chlorine, phosgene) on the battlefield during World War I. Despite the Chemical Weapons Convention banning these substances, they have still been employed in wars, terrorist attacks or political assassinations. Characterised by their high lethality, they target the nervous system by inhibiting the acetylcholinesterase (AChE) enzyme, preventing neurotransmission, which, if not treated rapidly, inevitably leads to serious injury or the death of the person intoxicated. The limited efficacy of current antidotes, known as AChE reactivators, pushes research towards new treatments. Numerous paths have been explored, from modifying the original pyridinium oximes to developing hybrid reactivators seeking a better affinity for the inhibited AChE. Another crucial approach resides in molecules more prone to cross the blood-brain barrier: uncharged compounds, bio-conjugated reactivators or innovative formulations. Our aim is to raise awareness on the threat and toxicity of organophosphorus nerve agents and to present the main synthetic efforts deployed since the first AChE reactivator, to tackle the task of efficiently treating victims of these chemical warfare agents.

Dabrafenib mitigates the neuroinflammation caused by ferroptosis in experimental autoimmune encephalomyelitis by up regulating Axl receptor.

Multiple sclerosis is an autoimmune disease that causes inflammatory damage to the central nervous system. At present, the pathogenesis of the disease is unknown. There is a lack of few effective therapy medications available. Therefore, it is necessary to further explore the pathogenesis of this illness and develop potential therapeutic drugs. Dabrafenib is potential therapeutic medicine for nervous system disease. In this study, we preliminarily studied the possible mechanism of dabrafenib in the treatment of multiple sclerosis from the perspective of ferroptosis. First, we observed that dabrafenib significantly improved symptoms of gait abnormalities, limb weakness or paralysis, and down-regulated levels of spinal cord inflammation in an experimental autoimmune encephalitis (EAE) model. Meanwhile, we also observed that dabrafenib could inhibit the proteins of ferroptosis in spinal cord tissue of EAE mice by Western blot. The results of immunohistochemical analysis showed that the effect of dabrafenib on ferroptosis mainly occurred in microglia. Second, dabrafenib was demonstrated to be able to inhibit the S phase of the cell cycle, reduce ROS levels, and reinstate mitochondrial activity in the LPS-induced BV2 inflammatory cell model. Futhermore, we found that dabrafenib inhibits P-JAK2 and P-STAT3 activation by acting Axl receptor, which in turn prevents neurogenic inflammation in microglia. The co-stimulated BV2 cell model with LPS and Erastin also verified these findings. Ultimately, the Axl knockout mice used to construct the EAE model allowed for the confirmation that dabrafenib prevented ferroptosis in microglia by up-regulating Axl receptor, which reduced the inflammatory demyelination associated with EAE. In summary, our research demonstrates the advantages of dabrafenib in multiple sclerosis treatment, which can prevent ferroptosis in microglia in multiple sclerosis through up-regulating Axl receptor, thus halting the progression of multiple sclerosis.

Intracranial hemorrhage caused by dabrafenib and trametinib therapy for metastatic melanoma.

Although generally well tolerated compared with chemotherapy, molecular targeted therapy used in metastatic melanoma may be associated with life-threatening toxicity. We report the case of a patient with metastatic melanoma treated by dabrafenib plus trametinib who developed intracranial hemorrhage. Physicians should be aware of this rare but life-threatening adverse event of B-rapidly accelerated fibrosarcoma (BRAF) and mitogen-activated protein kinase kinase (MEK) inhibitors. However, they should be also careful about the bleeding origin, which can prove to be a new onset of melanoma metastasis or anticoagulation overdose, or even an uncontrolled arterial hypertension.

Characterization of BRAFThr599dup Mutation as a Targetable Driver Mutation Identified in Lung Adenocarcinoma by Comprehensive Genomic Profiling.

PURPOSE: Understanding the function of BRAF mutants is crucial for determining the best treatment strategy. This study aimed to characterize a rare BRAF variant, BRAFThr599dup, which was identified in a patient with lung adenocarcinoma (LUAD) by comprehensive genomic profiling. MATERIALS AND METHODS: We report a case of LUAD with BRAFThr599dup treated with dabrafenib and trametinib. We conditionally expressed wild-type BRAF, BRAFV600E, or BRAFThr599dup in Ba/F3 cells and BEAS-2B cells. Ba/F3 cells carrying double-mutant BRAF (BRAFThr599dup/R509H, BRAFV600E/R509H, or BRAFK601E/R509H) that lacked the dimerizing ability were also established. Knockout of endogenous BRAF or CRAF in Ba/F3-BRAFThr599dup cells and Ba/F3-BRAFV600E cells was performed using the CRISPR/Cas9 system. Cell viability, mitogen-activated protein kinase (MAPK) signaling activity, and sensitivity to dabrafenib and trametinib were evaluated. RESULTS: The patient was revealed to have BRAFThr599dup-positive tumor cells as a predominant clone, and dabrafenib and trametinib treatment showed modest efficacy. In Ba/F3 cells, both BRAFThr599dup and BRAFV600E similarly caused interleukin-3-independent proliferation and activated the MAPK pathway. Moreover, BRAFThr599dup and BRAFV600E similarly caused a significant increase in the anchorage-independent growth ability of BEAS-2B cells. Along with Ba/F3-BRAFV600E cells, Ba/F3-BRAFThr599dup cells were highly sensitive to a monomer-specific BRAF inhibitor, dabrafenib, with a half-maximal inhibitory concentration value of 29.7 nM. In the absence of wild-type BRAF, wild-type CRAF, or an intact dimer interface, the ability to induce oncogenic addiction and MAPK pathway activation in Ba/F3-BRAFThr599dup cells was not affected, which was in contrast to the findings in the BRAFK601E/R509H double-mutant model. CONCLUSION: BRAFThr599dup is a potent driver oncogene that activates the MAPK pathway without the requirement for dimerization in vitro. Because BRAFThr599dup has been recurrently reported across various cancer types, our findings should be further investigated both mechanistically and clinically.

Response to Dabrafenib Plus Trametinib in a Patient With an Uncommon Activating BRAF Mutation: A First in Non-Small Cell Lung Cancer.

Mutations in BRAF are present in 4% of non-small cell lung cancer (NSCLC), of which half are well-characterized activating variants affecting codon 600 (classified as class I). These mutations, most commonly BRAF V600E, have been associated with response to BRAF/MEK-directed small molecule kinase inhibitors. NSCLC with kinase-activating BRAF mutations occurring at other codons (class II variants) represent a substantial portion of BRAF-mutated NSCLC, but use of targeted therapy in these tumors is still under investigation. Class II mutations have been described in other tumor types and have been associated with response to BRAF/MEK-targeted agents, although optimal treatment strategies for these patients are lacking. This report presents a case of a woman with metastatic NSCLC harboring a class II BRAF p.N486_P490del variant who had a sustained clinical response to combination therapy with dabrafenib and trametinib. This first report of the use of BRAF/MEK-targeted therapy for this variant in NSCLC supports consideration of such treatment for tumors with class II BRAF variants.

Exploiting BRAF mutations in the therapeutic approach towards oral and maxillofacial tumors.

Oral and maxillofacial tumors pose a significant clinical challenge due to their tendency to recur, despite advancements in surgical removal techniques. The jaw's intricate structure further complicates treatments and affects patient quality of life. Consequently, emphasis has shifted towards pharmacological interventions, to potentially reduce invasive surgical procedures. One promising approach targets BRAF mutations, specifically the common V600E mutation. BRAF, a critical protein kinase, regulates cell growth and differentiation via the RAS-RAF-MEK-ERK-MAP kinase pathway. A specific nucleotide change at position 1799, swapping Thymine (T) for Adenine (A), results in the V600E mutation, causing unchecked cell growth. This mutation is common in certain oral and maxillofacial tumors like ameloblastoma. A recent neoadjuvant therapy targeting BRAF, involving the use of dabrafenib and trametinib, has showcased a promising, safe, and effective strategy for organ preservation in the treatment of mandibular ameloblastoma. This convergence of molecular insights and targeted therapies holds the key to managing BRAF-mutated oral and maxillofacial tumors effectively, promising improved patient outcomes.

BRAF/MEK-targeted therapy in BRAF ex15 p.T599dup mutation-driven NSCLC: a case report.

BRAF mutations are found in 1-5% of non-small-cell lung cancer (NSCLC), with V600 and non-V600 accounting for approximately 50% each. It has been confirmed that targeted therapy with dabrafenib + trametinib is effective in patients with metastatic NSCLC carrying BRAF V600E mutations. Preclinical studies have shown that dabrafenib + trametinib may also have inhibitory effects on some types of non-V600E mutations, especially some class II BRAF mutations. However, the efficacy of dabrafenib + trametinib on non-V600E mutant NSCLC in clinical practice only exists in some case reports. Here, we report a case of NSCLC patient carrying BRAF ex15 p.T599dup, who showed a clinical response to the combined therapy of dabrafenib + trametinib.

Restoration of nerve agent impaired neuromuscular transmission in rat diaphragm by bispyridinium non-oximes - Structure-activity relationships.

Organophosphate (OP) poisoning is currently treated with atropine, oximes and benzodiazepines. The nicotinic signs, i.e., respiratory impairment, can only be targeted indirectly via the use of oximes as reactivators of OP-inhibited acetylcholinesterase. Hence, compounds selectively targeting nicotinic acetylcholine receptors (nAChRs) might fundamentally improve current treatment options. The bispyridinium compound MB327 has previously shown some therapeutic effect against nerve agents in vitro and in vivo. Nevertheless, compound optimization was deemed necessary, due to limitations (e.g., toxicity and efficacy). The current study investigated a series of 4-tert-butyl bispyridinium compounds and of corresponding bispyridinium compounds without substituents in a rat diaphragm model using an indirect field stimulation technique. The length of the respective linker influenced the ability of the bispyridinium compounds to restore muscle function in rat hemidiaphragms. The current data show structure-activity relationships for a series of bispyridinium compounds and provide insight for future structure-based molecular modeling.

Oxime-Linked Peptide-Daunomycin Conjugates as Good Tools for Selection of Suitable Homing Devices in Targeted Tumor Therapy: An Overview.

Chemotherapy is still one of the main therapeutic approaches in cancer therapy. Nevertheless, its poor selectivity causes severe toxic side effects that, together with the development of drug resistance in tumor cells, results in a limitation for its application. Tumor-targeted drug delivery is a possible choice to overcome these drawbacks. As well as monoclonal antibodies, peptides are promising targeting moieties for drug delivery. However, the development of peptide-drug conjugates (PDCs) is still a big challenge. The main reason is that the conjugates have to be stable in circulation, but the drug or its active metabolite should be released efficiently in the tumor cells. For this purpose, suitable linker systems are needed that connect the drug molecule with the homing peptide. The applied linker systems are commonly categorized as cleavable and non-cleavable linkers. Both the groups possess advantages and disadvantages that are summarized briefly in this manuscript. Moreover, in this review paper, we highlight the benefit of oxime-linked anthracycline-peptide conjugates in the development of PDCs. For instance, straightforward synthesis as well as a conjugation reaction proceed in excellent yields, and the autofluorescence of anthracyclines provides a good tool to select the appropriate homing peptides. Furthermore, we demonstrate that these conjugates can be used properly in in vivo studies. The results indicate that the oxime-linked PDCs are potential candidates for targeted tumor therapy.

No-observed-adverse-effect-level (NOAEL) assessment as an optimized dose of cholinesterase reactivators for the treatment of exposure to warfare nerve agents in mice.

Despite the international convention on the prohibition of chemical weapons ratified in 1997, the threat of conflicts and terrorist attacks involving such weapons still exists. Among these, organophosphorus-nerve agents (OPs) inhibit cholinesterases (ChE) causing cholinergic syndrome. The reactivation of these enzymes is therefore essential to protect the poisoned people. However, these reactivating molecules, mainly named oximes, have major drawbacks with limited efficacy against some OPs and a non-negligible ChE inhibitor potential if administered at an inadequate dose, an effect that they are precisely supposed to mitigate. As a result, this project focused on assessing therapeutic efficacy, in mice, up to the NOAEL dose, the maximum dose of oxime that does not induce any observable toxic effect. NOAEL doses of HI-6 DMS, a reference oxime, and JDS364. HCl, a candidate reactivator, were assessed using dual-chamber plethysmography, with respiratory ventilation impairment as a toxicity criterion. Time-course modeling parameters and pharmacodynamic profiles, reflecting the interaction between the oxime and circulating ChE, were evaluated for treatments at their NOAEL and higher doses. Finally, the therapeutic potential against OPs poisoning was determined through the assessment of protective indices. For JDS364. HCl, the NOAEL dose corresponds to the smallest dose inducing the most significant therapeutic effect without causing any abnormality in ChE activity. In contrast, for HI-6 DMS, its therapeutic benefit was observed at doses higher than its NOAEL, leading to alterations in respiratory function. These alterations could not be directly correlated with ChE inhibition and had no adverse effects on survival. They are potentially attributed to the stimulation of non-enzymatic cholinergic targets by HI-6 DMS. Thus, the NOAEL appears to be an optimal dose for evaluating the efficacy of oximes, particularly when it can be linked to respiratory alterations effectively resulting from ChE inhibition.

Characterization of dabrafenib-induced drug insensitivity via cellular barcoding and collateral sensitivity to second-line therapeutics.

Drug insensitivity is arguably one of the biggest challenges in cancer therapeutics. Although effective therapeutic solutions in cancer are limited due to the emergence of drug insensitivity, exploiting evolutionary understanding in this context can provide potential second-line therapeutics sensitizing the drug insensitive populations. Targeted therapeutic agent dabrafenib is used to treat CRC patients with BRAF V600E genotype and insensitivity to dabrafenib is often observed. Understanding underlying clonal architecture of dabrafenib-induced drug insensitivity and identification of potential second-line therapeutics that could sensitize dabrafenib insensitive populations remain to be elucidated. For this purpose, we utilized cellular barcoding technology to decipher dabrafenib-induced clonal evolution in BRAF V600E mutant HT-29 cells. This approach revealed the detection of both pre-existing and de novo barcodes with increased frequencies as a result of dabrafenib insensitivity. Furthermore, our longitudinal monitoring of drug insensitivity based on barcode detection from floating DNA within used medium enabled to identify temporal dynamics of pre-existing and de novo barcodes in relation to dabrafenib insensitivity in HT-29 cells. Moreover, whole-exome sequencing analysis exhibited possible somatic CNVs and SNVs contributing to dabrafenib insensitivity in HT-29 cells. Last, collateral drug sensitivity testing demonstrated oxaliplatin and capecitabine, alone or in combination, as successful second-like therapeutics in inducing collateral sensitivity in dabrafenib-insensitive HT-29 cells. Overall, our findings demonstrate clonal dynamics of dabrafenib-insensitivity in HT-29 cells. In addition, oxaliplatin and capecitabine, alone or in combination, were successful second-line therapeutics in inducing collateral sensitivity in dabrafenib-insensitive HT-29 cells.

A phase 1 study of triple-targeted therapy with BRAF, MEK, and AKT inhibitors for patients with BRAF-mutated cancers.

BACKGROUND: Aberrant PI3K/AKT signaling in BRAF-mutant cancers contributes to resistance to BRAF inhibitors. The authors examined dual MAPK and PI3K pathway inhibition in patients who had BRAF-mutated solid tumors (ClinicalTrials.gov identifier NCT01902173). METHODS: Patients with BRAF V600E/V600K-mutant solid tumors received oral dabrafenib at 150 mg twice daily with dose escalation of oral uprosertib starting at 50 mg daily, or, in the triplet cohorts, with dose escalation of both oral trametinib starting at 1.5 mg daily and oral uprosertib starting at 25 mg daily. Dose-limiting toxicities (DLTs) were assessed within the first 56 days of treatment. Radiographic responses were assessed at 8-week intervals. RESULTS: Twenty-seven patients (22 evaluable) were enrolled in parallel doublet and triplet cohorts. No DLTs were observed in the doublet cohorts (N = 7). One patient had a DLT at the maximum administered dose of triplet therapy (dabrafenib 150 mg twice daily and trametinib 2 mg daily plus uprosertib 75 mg daily). Three patients in the doublet cohorts had partial responses (including one who had BRAF inhibitor-resistant melanoma). Two patients in the triplet cohorts had a partial response, and one patient had an unconfirmed partial response. Pharmacokinetic data suggested reduced dabrafenib and dabrafenib metabolite exposure in patients who were also exposed to both trametinib and uprosertib, but not in whose who were exposed to uprosertib without trametinib. CONCLUSIONS: Concomitant inhibition of both the MAPK and PI3K-AKT pathways for the treatment of BRAF-mutated cancers was well tolerated, leading to objective responses, but higher level drug-drug interactions affected exposure to dabrafenib and its metabolites.

A single post-exposure oxime RS194B treatment rapidly reactivates acetylcholinesterase and reverses acute symptoms in macaques exposed to diethylphosphorothioate parathion and chlorpyrifos insecticides.

Millions of individuals globally suffer from inadvertent, occupational or self-harm exposures from organophosphate (OP) insecticides, significantly impacting human health. Similar to nerve agents, insecticides are neurotoxins that target and inhibit acetylcholinesterase (AChE) in central and peripheral synapses in the cholinergic nervous system. Post-exposure therapeutic countermeasures generally include administration of atropine with an oxime to reactivate the OP-inhibited AChE. However, animal model studies and recent clinical trials using insecticide-poisoned individuals have shown minimal clinical benefits of the currently approved oximes and their efficacy as antidotes has been debated. Currently used oximes either reactivate poorly, do not readily cross the blood-brain barrier (BBB), or are rapidly cleared from the circulation and must be repeatedly administered. Zwitterionic oximes of unbranched and simplified structure, for example RS194B, have been developed that efficiently cross the BBB resulting in reactivation of OP-inhibited AChE and dramatic reversal of severe clinical symptoms in mice and macaques exposed to OP insecticides or nerve agents. Thus, a single IM injection of RS194B has been shown to rapidly restore blood AChE and butyrylcholinesterase (BChE) activity, reverse cholinergic symptoms, and prevent death in macaques following lethal inhaled sarin and paraoxon exposure. The present macaque studies extend these findings and assess the ability of post-exposure RS194B treatment to counteract oral poisoning by highly toxic diethylphosphorothioate insecticides such as parathion and chlorpyrifos. These OPs require conversion by P450 in the liver of the inactive thions to the active toxic oxon forms, and once again demonstrated RS194B efficacy to reactivate and alleviate clinical symptoms within 60 mins of a single IM administration. Furthermore, when delivered orally, the Tmax of RS194B at 1-2 h was in the same range as those administered IM but were maintained in the circulation for longer periods greatly facilitating the use of RS194B as a non-invasive treatment, especially in isolated rural settings.

Recent advances in cholinergic mechanisms as reactions to toxicity, stress, and neuroimmune insults.

This review presents recent studies of the chemical and molecular regulators of acetylcholine (ACh) signaling and the complexity of the small molecule and RNA regulators of those mechanisms that control cholinergic functioning in health and disease. The underlying structural, neurochemical, and transcriptomic concepts, including basic and translational research and clinical studies, shed new light on how these processes inter-change under acute states, age, sex, and COVID-19 infection; all of which modulate ACh-mediated processes and inflammation in women and men and under diverse stresses. The aspect of organophosphorus (OP) compound toxicity is discussed based on the view that despite numerous studies, acetylcholinesterase (AChE) is still a vulnerable target in OP poisoning because of a lack of efficient treatment and the limitations of oxime-assisted reactivation of inhibited AChE. The over-arching purpose of this review is thus to discuss mechanisms of cholinergic signaling dysfunction caused by OP pesticides, OP nerve agents, and anti-cholinergic medications; and to highlight new therapeutic strategies to combat both the acute and chronic effects of these chemicals on the cholinergic and neuroimmune systems. Furthermore, OP toxicity was examined in view of cholinesterase inhibition and beyond in order to highlight improved small molecules and RNA therapeutic strategies and assess their predicted pitfalls to reverse the acute toxicity and long-term deleterious effects of OPs.