SEARCH · PubMed Health

Results for “mutational profiling”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 1,297 records · Page 72Linked to original sources

PubMed2001

Use of a LightCycler gyrA mutation assay for rapid identification of mutations conferring decreased susceptibility to ciprofloxacin in multiresistant Salmonella enterica serotype Typhimurium DT104 isolates.

A LightCycler-based PCR-hybridization gyrA mutation assay (GAMA) was developed to rapidly detect gyrA point mutations in multiresistant (MR) Salmonella enterica serotype Typhimurium DT104 with decreased susceptibility to ciprofloxacin (MIC, 0.25 to 1.0 mg/liter). Ninety-two isolates (49 human, 43 animal) were tested with three individual oligonucleotide probes directed against an Asp-87-to-Asn (GAC-->AAC) mutation, an Asp-87-to-Gly (GAC-->GGC) mutation, and a Ser-83-to-Phe (TCC-->TTC) mutation. Strains homologous to the probes could be distinguished from strains that had different mutations by their probe-target melting temperatures. Thirty-seven human and 30 animal isolates had an Asp-87-to-Asn substitution, 6 human and 6 animal isolates had a Ser-83-to-Phe substitution, and 5 human and 2 animal isolates had an Asp-87-to-Gly substitution. The remaining six strains all had mismatches with the three probes and therefore different gyrA mutations. The sequencing of gyrA from these six isolates showed that one human strain and two animal strains had an Asp-87-to-Tyr (GAC-->TAC) substitution and two animal strains had a Ser-83-to-Tyr (TCC-->TAC) substitution. One animal strain had no gyrA mutation, suggesting that this isolate had a different mechanism of resistance. Fifty-eight of the strains tested were indistinguishable by several different typing methods including antibiograms, pulsed-field gel gel electrophoresis, and plasmid profiling, although they could be further subdivided according to gyrA mutation. This study confirmed that MR DT104 with decreased susceptibility to ciprofloxacin from humans and food animals in England and Wales may have arisen independently against a background of clonal spread of MR DT104.

Animals↗

PubMed1990

Development of "oligotyping" for characterization and molecular epidemiology of TEM beta-lactamases in members of the family Enterobacteriaceae.

Based on the DNA sequences of blaTEM-1 and blaTEM-2, which encode parental penicillinases TEM-1 and TEM-2, respectively, and blaTEM-3, blaTEM-4, blaTEM-5, blaTEM-6, and blaTEM-7, which encode extended-spectrum beta-lactamases, we designed heptadecanucleotides to discriminate point mutations in five loci. Determination of the hybridization profiles by colony hybridization with this selection of probes, termed "oligotyping," allowed characterization of the TEM variants present in 265 clinical isolates of the family Enterobacteriaceae that exhibit synergism between a penicillinase inhibitor and broad-spectrum cephaslosporins. Among the 222 strains harboring TEM enzymes, Klebsiella pneumoniae (48%) and Escherichia coli (21%) were predominant, and TEM-3 was the most common enzyme (60%). Penicillinases TEM-1 and TEM-2 were detected alone (15 and 1%, respectively), combined (1%), or associated with another TEM beta-lactamase (17 and 6%, respectively). Fourteen variants, including seven new enzymes, were detected. One, TEM-13, was a new penicillinase with the same isoelectric point and substrate range as TEM-2 but differed by a single amino acid substitution, whereas the others, TEM-14 to TEM-19, were extended-spectrum beta-lactamases that consisted of novel combinations of known amino acid substitutions. Different TEM variants were found to coexist within the same cells. A patient could harbor two or three different strains that encoded the same enzyme or two indistinguishable isolates that produced distinct TEM beta-lactamases.

Amino Acids↗

PubMed2006

Antiviral drug resistance: clinical consequences and molecular aspects.

Antiviral drug resistance now poses a major problem for the management of patients with chronic hepatitis B. In theory, resistance may be prevented if a sufficiently potent antiviral drug, or combination of antiviral agents, is used that prevents viral replication and thereby the ongoing selection of hepatitis B virus quasispecies. Emergence of drug resistance in patients with hepatitis B generally results in progression of liver disease and in some cases, significant clinical deterioration if hepatic reserve is compromised. Currently, there are two major patterns of resistance mutations found in the viral reverse transcriptase (rt) that can be selected during monotherapy: (1) those that include the codon rtM204, which is part of the catalytic domain (YMDD) of the enzyme; (2) and those that do not include the codon. The rtM204I/V is selected by lamivudine and L-nucleosides. It is also part of the entecavir resistance profile and the tenofovir-lamivudine combination resistance profile. In contrast, resistance to adefovir is associated with mutations at rtN236T +/- rtA181V. A reasonable clinical goal is to develop an overall strategy that prevents the selection of resistance. These strategies have yet to be optimized for hepatitis B, but may include multiple therapies such as immune-based therapies in combination with one or more nucleoside analogue treatments. Future treatment protocols can be modeled on the use of multiple agents comprising highly active anti-retroviral therapy regimens that have been developed for the successful management of patients infected with human immunodeficiency virus.

Antiviral Agents↗

PubMed2000

Neuronal ceroid lipofuscinoses: research update.

This study describes the phenotype/genotype analysis of 159 probands with neuronal ceroid lipofuscinosis (37 CLN1, 72 classic CLN2, 10 variant LINCL, and 40 CLN3) collected at the New York State Institute for Basic Research in Developmental Disabilities (IBR). Phenotype/genotype comparison showed that mutations in the CLN1 gene were associated with different phenotypes: infantile, late infantile, and juvenile. Two common mutations (223A-->C and 451C-->T) were found in 26 of 37 CLN1 subjects (64% of alleles examined). A nonsense point mutation, 451C-->T, was the most common in CLN1 subjects with infantile onset at 0-2 years, accounting for 50% of alleles studied. A missense point mutation, 223A-->C, was the most common among CLN1 subjects with juvenile onset older than 4 years, accounting for 45% of alleles examined. Twenty-one other CLN1 mutations were identified in 4 of 37 subjects with infantile onset, 6 of 37 with late-infantile onset, and 6 of 37 with juvenile onset. All CLN1 probands were palmitoyl-protein thioesterase (PPT)-deficient and showed granular osmiophilic deposits (GROD) at the electron microscopic (EM) level. In the group of classic CLN2 (72 probands), two common mutations were found: an intronic 3556G-->C transversion in the invariant AG of 3' splice junction in 55% of probands, and a nonsense mutation 3670C-->T in 30% of probands. Classic late-infantile onset (2-4 years) was found in 68 of 72 (95%) cases, whereas juvenile onset (> 4 years) occurred only in 4 of 72 (5%) cases. All probands had deficiency of tripeptidyl-peptidase I (TPP1) activity and, at the EM level, curvilinear profiles. Ten probands with late-infantile onset did not show mutations in the CLN2 gene, had normal TPP1 activity, and at the EM level had mixed profiles. Further studies are in progress to identify genetic defect(s) in these subjects. The CLN3 group (40 probands) was divided into two categories: classic or typical presentation, and delayed classic or atypical presentation. All CLN3 patients had onset of symptoms after 4 years of age. In 40 probands, the 1.02-kb common deletion was found in one or two alleles of the CLN3 gene. Homozygotes for the common CLN3 deletion showed the classic phenotype. The phenotype in compound heterozygotes was either the classic or the delayed classic or atypical form. Thus, our study indicates that some mutations in the CLN1 and CLN2 genes may be associated with juvenile onset of the disease process and a more benign clinical course. Interfamilial and intrafamilial variations also were found, especially in the speed of becoming blind and neurologically disabled.

Aminopeptidases↗

PubMed2005

Skeletal muscle gene expression profiling in mitochondrial disorders.

Extremely variable clinic and genetic features characterize mitochondrial encephalomyopathy (MEM). Pathogenic mitochondrial DNA (mtDNA) defects can be divided into large-scale rearrangements and single point mutations. Clinical manifestations become evident when a threshold percentage of the total mtDNA is mutated. In some MEM, the "mutant load" in an affected tissue is directly related to the severity of the phenotype. However, the clinical phenotype is not simply a direct consequence of the relative abundance of mutated mtDNA. Other factors, such as nuclear background, can contribute to the disease process, resulting in a wide range of phenotypes caused by the same mutation. Using Affymetrix oligonucleotide cDNA microarrays (HG-U133A), we studied the gene expression profile of muscle tissue biopsies obtained from 12 MEM patients [4 common 4977 bp deleted mtDNA and 8 A3243G: 4 progressive external ophthalmoplegia (PEO) and 4 mitochondrial myopathy, encephalopathy, lactic cidosis, and stroke-like episodes syndrome (MELAS) phenotypes] compared with age-matched healthy individuals. We found several differentially expressed genes: 35 were markedly up-regulated in the mtDNA macro-deletion group (vs. the control group) and 4 decreased; 56 genes were dysregulated in A3243G-related disorders (53 down-regulated in PEO and 3 up-regulated in MELAS). Finally, 12 genes were similarly regulated in the majority of the MEM patients under study. Amongst these, we identified an increased expression of genes related to the metabolism of the amino groups, as well as of several genes involved in genetic information processing. Moreover, few genes were similarly decreased in MEM patients vs. the control group. Real-time PCR demonstrated excellent reproducibility of the microarray-based findings. The observed expression changes are likely to represent a molecular signature for mitochondrial disorders. Furthermore, the differential expression profile of MELAS(A3243G) vs. PEO(A3243G) may support a role of nuclear background in contributing to these different clinical phenotypes. MEM microarray data are available from GEO database (http://www.ncbi.nlm.nih.gov/geo/) with the accession number: GSE1462.

Adolescent↗

PubMed2005

Low accumulation of L90M in protease from subtype F HIV-1 with resistance to protease inhibitors is caused by the L89M polymorphism.

BACKGROUND: This work evaluates the role of subtype F human immunodeficiency virus type 1 (HIV-1) protease (PR) substitutions L89M and L90M in viral replication and resistance to PR inhibitors (PIs). METHODS: Subtype B and F PR genes were subjected to site-directed mutagenesis, to create and reverse the methionine at positions 89 and 90. Viruses were re-created in cell culture, and their replicative capacity was assessed by fitness assay. Generated viruses were also phenotyped for PI resistance. RESULTS: The subtype F clone (89M90L) showed a replicative capacity comparable to that of the PI-susceptible subtype B clone (89L90L) and was more fit than the L89M mutated subtype B clone (89M90L). Both 89M90M subtype B and F clones presented the lowest fitness s values. The L89M mutation impacted phenotypic resistance to all PIs in half of the subtype F isolates but not in the subtype B isolates. Subtype F isolates presented a phenotypic profile similar to that of subtype B isolates when the M89L mutation was introduced. CONCLUSION: The L89M mutation in subtype F viruses is a high genetic barrier to the accumulation of the L90M resistance mutation and can function as a resistance mutation, depending on the presence of other polymorphisms in the subtype F PR backbone.

Amino Acid Sequence↗

PubMed2005

Moyamoya syndrome with intraventricular hemorrhage in an adult with factor V Leiden mutation.

OBJECTIVE: To report a case of proximal occlusion of 2 major cerebral vessels associated with moyamoya network circulation that manifested by spontaneous intraventricular hemorrhage. DESIGN: Case report. PATIENT AND RESULTS: A 36-year-old Syrian man presented with symptoms of sudden-onset headache, neck stiffness, and confusion. The computed tomography scan of his brain showed intraventricular bleeding, and the subsequent 4 vessel angiographies revealed occlusion of the left middle and anterior cerebral arteries with moyamoya appearance in the terminal branches. The coagulation profile showed the presence of heterozygous factor V Leiden mutation. The patient was treated conservatively until resolution of his blood clot, and later he was started on oral anticoagulation. CONCLUSION: Factor V Leiden mutation may cause large cerebral vessel occlusion with moyamoya syndrome in adults.

Adult↗

PubMed2005

Identification of mutations from phenotype-driven ENU mutagenesis in mouse chromosome 7.

We have used the new high-throughput mutation-scanning technique temperature-gradient capillary electrophoresis (TGCE) for the identification of point mutations induced by N-ethyl-N-nitrosourea (ENU) in the mouse genome. TGCE detects the presence of heteroduplex molecules formed between a wild-type gene segment and the corresponding homologous segment containing an induced mutation or a naturally occurring single nucleotide polymorphism (SNP). Partially denatured heteroduplex molecules are resolved from homoduplexes by virtue of their differential mobilities during capillary electrophoresis conducted in a finely controlled temperature gradient. Simultaneous heteroduplex analysis of 96 amplicons ranging from 150 to 600 bp in size is achieved in approximately 45 min without the need for predetermining the melting profile of each fragment. Initially, we exploited known mouse mutations to develop TGCE protocols for analyzing unpurified PCR samples amplified from crude tail-DNA preparations. TGCE was then applied to the rapid identification of three new ENU-induced mutations recovered from regional mutagenesis screens of a segment of mouse Chromosome 7. Enzyme assays and quantitative reverse transcription-PCR (qRT-PCR) methods validated these new mutations. Our data demonstrate that rapid mutation scanning with TGCE, followed by sequence verification only of detected positives, is an efficient approach to the identification of point mutations in the mouse genome.

Animals↗

PubMed2005

Distinctive gene expression pattern in VH3-21 utilizing B-cell chronic lymphocytic leukemia.

The usage of the immunoglobulin (Ig) V(H)3-21 gene is associated with poor prognosis in B-cell chronic lymphocytic leukemia (B-CLL) despite V(H) gene mutation status. Many V(H)3-21+ patients also display restricted heavy- and light-chain Ig gene rearrangements, implying a role of antigen selection in disease development. To explore the specific phenotypic/genotypic features among V(H)3-21+ B-CLLs, we compared gene expression patterns in 15 V(H)3-21+ and 24 non-V(H)3-21 patients (11 with unmutated and 13 with mutated V(H) genes) using Affymetrix microarray analysis (approximately 12,500 genes). A distinct expression profile was identified for V(H)3-21+ patients in contrast to the Ig-unmutated and -mutated groups. By applying different algorithms, the data enabled an efficient class discrimination of the V(H)3-21+ subset based on 27 or 57 genes. A set of genes was sorted out which, using different analytical methods, consistently gave a distinction between V(H)3-21+ and non-V(H)3-21 samples. Several of these genes are involved in regulation of DNA replication/cell-cycle control, transcription and protein kinase activity, which may render the V(H)3-21+ cells with a higher proliferative drive. However, no clear evidence of increased B-cell receptor signaling was found in the V(H)3-21+ group. Altogether, our identification of a specific V(H)3-21 profile may provide insights into the pathogenesis of the V(H)3-21+ subgroup.

Aged↗

PubMed1991

Structural basis for broad specificity in alpha-lytic protease mutants.

Binding pocket mutants of alpha-lytic protease (Met 192----Ala and Met 213----Ala) have been constructed recently in an effort to create a protease specific for Met just prior to the scissile bond. Instead, mutation resulted in proteases with extraordinarily broad specificity profiles and high activity [Bone, R., Silen, J. L., & Agard, D. A. (1989) Nature 339, 191-195]. To understand the structural basis for the unexpected specificity profiles of these mutants, high-resolution X-ray crystal structures have been determined for complexes of each mutant with a series of systematically varying peptidylboronic acids. These inhibitory analogues of high-energy reaction intermediates provide models for how substrates with different side chains interact with the enzyme during the transition state. Fifteen structures have been analyzed qualitatively and quantitatively with respect to enzyme-inhibitor hydrogen-bond lengths, buried hydrophobic surface area, unfilled cavity volume, and the magnitude of inhibitor accommodating conformational adjustments (particularly in the region of another binding pocket residue, Val 217A). Comparison of these four parameters with the Ki of each inhibitor and the kcat and Km of the analogous substrates indicates that while no single structural parameter consistently correlates with activity or inhibition, the observed data can be understood as a combination of effects. Furthermore, the relative contribution of each term differs for the three enzymes, reflecting the altered conformational energetics of each mutant. From the extensive structural analysis, it is clear that enzyme flexibility, especially in the region of Val 217A, is primarily responsible for the exceptionally broad specificity observed in either mutant. Taken together, the observed patterns of substrate specificity can be understood to arise directly from interactions between the substrate and the residues lining the specificity pocket and indirectly from interactions between peripheral regions of the protein and the active-site region that serve to modulate active-site flexibility.

Alanine↗

PubMed2005

Genotype-phenotype relationships in hepatocellular tumors from mice and man.

Experimentally induced liver tumors in mice harbor activating mutations in either Catnb (beta-catenin) or Ha-ras, according to the carcinogenic treatment. We have now investigated by microarray analysis the gene expression profiles in tumors of the two genotypes. In total, 364 genes or expressed sequences with aberrant expression relative to normal liver were identified, but only 30 of these demonstrated unidirectional changes in both tumor types. Several functional clusters were identified that involve changes in amino acid utilization and ammonia disposition in Catnb-mutated tumors as opposed to alterations in lipid and cholesterol metabolism in Ha-ras-mutated tumors. Moreover, several genes coding for inhibitory molecules within the Wnt-signaling pathway were upregulated in Catnb-mutated tumors, suggesting induction of a negative feedback loop, whereas Ha-ras-mutated tumors showed alterations in the expression of several genes functional in monomeric G-protein signaling. We conclude that mouse hepatoma cells adopt different evolutionary strategies that allow for their selective outgrowth under variable environmental conditions. Human hepatocellular cancers (HCC) lack RAS mutations but are frequently mutated in CTNNB1, the human Catnb ortholog. The set of genes aberrantly expressed in Catnb-mutated mouse tumors was used to screen, by expression profiling, for dysregulation of orthologous genes within a panel of 25 HCCs, of which 10 were CTNNB1-mutated. HCCs with activated beta-catenin displayed a gene expression profile that was similar to Catnb-mutated mouse tumors but distinct from the other human HCCs. In conclusion, expression fingerprints may be used for diagnostic purposes and potential new therapeutic intervention strategies. Supplementary material for this article can be found on the HEPATOLOGY website (http://www.interscience.wiley.com/jpages/0270-9139/suppmat/index/html).

Animals↗

PubMed2026

Integrated Genomic and Immune Profiling of Early Onset Lung Cancer in East Asians Reveals a Distinct Molecular Architecture.

BACKGROUND: The age cut-off for early-onset lung cancer (EOLC) varies across studies (40-50 years). Here, we define EOLC as diagnosis at ≤ 40 years, a threshold identifying a subgroup with distinct clinical characteristics. However, whether EOLC differs fundamentally from late-onset lung cancer (LOLC) at the molecular level and represents a distinct subtype requiring different management remains unclear. METHODS: This integrated analysis included genomic and immune profiling data from 8,021 lung cancer patients, comprising 302 EOLC and 7,719 LOLC cases. Using targeted sequencing, we assessed somatic and germline alterations, mutational signatures, and immune biomarkers including tumor mutational burden (TMB), MSI status, and PD-L1 expression. RESULTS: EOLC patients were more often female, had adenocarcinoma, and earlier-stage disease. Molecular profiling revealed significant enrichment of ERBB2 mutations in EOLC, while KRAS, TP53, and MET mutations were more common in LOLC. Mutational signature analysis indicated tobacco-related signatures predominated in LOLC, whereas endogenous processes contributed more substantially in EOLC. Germline analysis showed a higher burden of pathogenic variants in EOLC (14.57% vs. 8.93%, P < .01), with TP53 and BRCA1 being particularly prominent. Immunologically, LOLC tumors exhibited higher TMB and PD-L1 positivity. CONCLUSION: Integrated profiling establishes EOLC as a distinct molecular subtype, defined by a unique triad: an ERBB2-driven somatic profile, germline susceptibility in DNA damage response pathways, and an endogenous mutagenic process within a low-TMB microenvironment. The findings are specific to the selected threshold and should be interpreted accordingly, while elucidating EOLC pathogenesis and supporting age-specific management strategies.

Humans↗

PubMed2001

Guidelines for reporting clinical features in cases with MECP2 mutations.

An international group recommends that papers relating phenotypes to genotypes involving mutations in the X chromosome gene MECP2 should provide a minimum data set reporting the range of disturbances frequently encountered in Rett Syndrome. A simple scoring system is suggested which will facilitate comparison among the various clinical profiles. Features are described which should prompt screening for MECP2 mutations.

Chromosomal Proteins, Non-Histone↗

PubMed2006

Novel myelin protein zero mutation (Arg36Trp) in a patient with acute onset painful neuropathy.

We present a patient with acute onset painful polyneuropathy found to have a novel MPZ mutation (Arg36Trp). The Arg36Trp mutation described in this report occurs at a putative adhesion interface. An alternative explanation for his polyneuropathy was not found and his mother was identified to have polyneuropathy and carry the same mutation. Two hundred normal controls were without this base alteration. The temporal profile of the index case may provide further indirect evidence suggesting an immune mechanism contributing to the pathogenesis of some cases of MPZ mutations. We predict that other rapid symptom onset polyneuropathies will be found to have direct genetic susceptibility.

Acute Disease↗

PubMed2001

Compound heterozygous familial hypercholesterolemia and familial defective apolipoprotein B-100 produce exaggerated hypercholesterolemia.

BACKGROUND: Familial hypercholesterolemia (FH) and familial defective apolipoprotein B-100 (FDB) represent ligand-receptor disorders that are complementary. Individuals with both FH and FDB are unusual. We report a family with both disorders and the impact of the mutations on the phenotypes of the family members. METHODS: We used single strand conformation polymorphism (SSCP) and denaturing gradient gel electrophoresis (DGGE) for genetic analysis of all 18 exons and the promoter region of the LDL receptor and DGGE for genetic analysis of the apolipoprotein B-100 (apo B-100) gene. The functional significance of the apo B-100 mutation was studied using a U937 cell proliferation assay. Fasting serum lipid profiles were determined for the index case and seven first-degree relatives. RESULTS: One of the patient's sisters had a missense mutation (Asp(407)-->Lys) in exon 9 of the LDL receptor and a serum LDL-cholesterol concentration of 4.07 mmol/L. Four other first-degree relatives had hyperlipidemia but no LDL-receptor mutation. However, these subjects had a mutation of the apo B-100 gene (Arg(3500)-->Trp). The cell proliferation rate of U937 cells fed with LDL from other subjects with the same mutation was fourfold less than that of controls. The index case had both FH- and FDB-related mutations. Her serum LDL-cholesterol (9.47 mmol/L) was higher than all other relatives tested. CONCLUSIONS: Existence of both FH and FDB should be considered in families with LDL-receptor mutations in some but not all individuals with hypercholesterolemia or when some individuals in families with FH exhibit exaggerated hypercholesterolemia.

Adolescent↗

PubMed2005

Mutations in the "lid" region affect chain length specificity and thermostability of a Pseudomonas fragi lipase.

The cold-adapted Pseudomonas fragi lipase (PFL) displays highest activity on short-chain triglyceride substrates and is rapidly inactivated at moderate temperature. Sequence and structure comparison with homologous lipases endowed with different substrate specificity and stability, pointed to three polar residues in the lid region, that were replaced with the amino acids conserved at equivalent positions in the reference lipases. Substitutions at residues T137 and T138 modified the lipase chain-length preference profile, increasing the relative activity towards C8 substrates. Moreover, mutations conferred to PFL higher temperature stability. On the other hand, replacement of the serine at position 141 by glycine destabilized the protein.

Amino Acid Sequence↗

PubMed2026

Ifebemtinib plus garsorasib in previously treated metastatic colorectal cancer with KRASG12C mutation: a multicentre, randomised, phase 1b/2 trial.

BACKGROUND: Ifebemtinib is a potent oral focal adhesion kinase inhibitor. Preclinical evidence supports combining ifebemtinib with the KRASG12C inhibitor garsorasib. This study aimed to evaluate this combination in KRASG12C-mutated solid tumours. METHODS: This multicentre, phase 1b/2 study had a phase 1b component to establish the recommended phase 2 dose and a phase 2 multitumour expansion component. In phase 1b, the safety and tolerability of ifebemtinib combined with garsorasib was assessed using a 3 + 3 design in KRASG12C-mutated solid tumours. No dose-limiting toxic effects were observed, and the recommended phase 2 dose was established as ifebemtinib 100 mg orally once daily plus garsorasib 600 mg orally twice daily. Here, we report the results of the cohort of previously treated KRASG12C-mutated metastatic colorectal cancer from phase 2 expansion. Eligible patients (aged ≥18 years) who had histologically confirmed locally advanced or metastatic colorectal cancer harbouring the KRASG12C mutation, an Eastern Cooperative Oncology Group performance-status score of 0 or 1, and had disease progression after previous irinotecan-based or oxaliplatin-based combination therapy, were recruited from seven of nine participating tertiary hospitals in China. On the basis of the recommended phase 2 dose, phase 2 comprised a single-arm study to evaluate the safety and efficacy of ifebemtinib combined with garsorasib and an open-label, randomised study in which patients were randomly assigned (1:1) to receive ifebemtinib plus garsorasib or garsorasib alone, by use of centralised computer-generated block randomisation with no stratification. Investigators were masked to the block size. The primary efficacy endpoint of phase 2 was investigator-assessed objective response rate (Response Evaluation Criteria in Solid Tumours, version 1.1), assessed in the safety analysis set in the single-arm study and in all randomly assigned patients (intention-to-treat population) in the randomised study. At least six objective responses (safety analysis set) were required in the single-arm study to proceed to the randomised study. This study is registered with ClinicalTrials.gov, NCT06166836 and NCT05379946, and is active but not recruiting. FINDINGS: Between April 7, 2023 and Dec 13, 2024, 51 patients were enrolled in phase 2 (15 in the single-arm study and 36 in the randomised study). In the single-arm study, the median age was 53 years (IQR 39 to 63), nine (60%) patients were female, six (40%) were male, and all were Asian. In the randomised study, the median age was 51 years (IQR 42 to 59) in the combination group and 63 years (IQR 54 to 66) in the monotherapy group, 24 (67%) were female, 12 (33%) were male, and all patients were Asian. In the single-arm part, the confirmed objective response rate was 46·7% (95% CI 21·3 to 73·4). Seven patients had partial responses, triggering progression to the randomised study. In the randomised study, the confirmed objective response rate was 38·9% (95% CI 17·3 to 64·3) with the combination therapy versus 16·7% (95% CI 3·6 to 41·4) with garsorasib alone (between-group difference 22·2%, 95% CI -7·7 to 49·1; one-sided p=0·068). In the single-arm study, grade 3 treatment-related adverse events occurred in four (27%) of 15 patients, and in the randomised study, grade 3 treatment-related adverse events occurred in six (33%) of 18 patients in the combination group and five (28%) of 18 in the garsorasib group. Grade 3 treatment-related adverse events occurring in at least two patients were diarrhoea (six [18%]), proteinuria (two [6%]), and intestinal obstruction (two [6%]) in patients treated with combination therapy (combined), and increased alanine aminotransferase and γ-glutamyltransferase (two [11%] each) in patients treated with garsorasib alone. Serious adverse events occurred in ten (30%) patients in the combination group and in four (22%) patients in the monotherapy group. One patient in the garsorasib monotherapy group died due to the underlying malignancy within 30 days after completing study treatment, which was reported as a serious adverse event. The death was assessed by the investigators as not related to garsorasib. No grade 4 treatment-related adverse events or treatment-related deaths were reported across all cohorts. INTERPRETATION: The combination of ifebemtinib and garsorasib showed promising anticancer activity and manageable safety profile in previously treated patients with KRASG12C-mutated metastatic colorectal cancer. Although the improvement in response rate did not reach statistical significance in the randomised study, these findings support further evaluation of ifebemtinib plus garsorasib in this population. FUNDING: InxMed, InventisBio, National Natural Science Foundation of China, the Jian Bing Ling Yan + X Research and Development Program of Zhejiang Province, and the Zhejiang Province Medical and Health Science and Technology Plan Project.

Humans↗

PubMed2006

Tamoxifen and raloxifene differ in their functional interactions with aspartate 351 of estrogen receptor alpha.

The bulky side chains of antiestrogens hinder folding of the ligand binding domain (LBD) of estrogen receptors (ERs) into a transcriptionally active conformation. The presence of a tertiary amine in the side chain of raloxifene, which interacts with a negatively charged residue in helix H3 of the ER LBD [Asp351 in human (h)ERalpha], is important for antiestrogenicity in animal and cellular models. To better understand the molecular basis of the differential activity of tamoxifen and raloxifene, we have examined the influence of tertiary amine substituents and of mutations at position 351 in hERalpha on the activity profiles of tamoxifen derivatives. Results obtained in several cellular model systems suggest that the degree of antagonist activity of tamoxifen derivatives does not strictly correlate with the basicity of the side chain but depends on an optimal spatial relationship between the tertiary amine of these antiestrogens and the negative charge at position 351. Although altering the position of the negative charge at residue 351 (mutation D351E) had little effect on transcriptional activity in the presence of tamoxifen, it drastically increased the partial agonist activity of a tamoxifen derivative with improved antagonist activity as well as that of raloxifene. Our results suggest that contrary to raloxifene, tamoxifen and most of its derivatives do not interact with Asp351 in an optimal manner, although this can be improved by modifying tertiary amine substituents.

Aspartic Acid↗