Molecular mechanisms of the anti-cancer drug, LY2874455, in overcoming the FGFR4 mutation-based resistance

AbstractIn recent years, many strategies have been used to overcome the fibroblast growth factor receptor (FGFR) tyrosine kinase inhibitors (TKIs) resistance caused by different mutations. LY2874455 (or 6LF) is a pan-FGFR inhibitor which is identified as the most efficient TKI for all resistant mutations in FGFRs. Here, we perform a comparative dynamics study of wild type (WT) and the FGFR4 V550L mutant for better understanding of the 6LF inhibition mechanism. Our results confirm that the pan-FGFR inhibitor 6LF can bind efficiently to both WT and V550L FGFR4. Moreover, the communication network analysis indicates that in apo-WT FGFR4, αD–αE loop behaves like a switch between open and close states of the substrate-binding pocket in searching of its ligand. In contrast, V550L mutation induces the active conformation of the FGFR4 substrate-binding pocket through disruption of αD–αE loop and αG helix anti-correlation. Interestingly, 6LF binding causes the rigidity of hinge and αD helix regions, which results in overcoming V550L induced resistance. Collectively, the results of this study would be informative for designing more efficient TKIs for more effective targeting of the FGFR signaling pathway.

Download Full-text

Structural basis for substrate specificity of heteromeric transporters of neutral amino acids

Proceedings of the National Academy of Sciences ◽

10.1073/pnas.2113573118 ◽

2021 ◽

Vol 118 (49) ◽

pp. e2113573118

Author(s):

Carlos F. Rodriguez ◽

Paloma Escudero-Bravo ◽

Lucía Díaz ◽

Paola Bartoccioni ◽

Carmen García-Martín ◽

...

Keyword(s):

Amino Acids ◽

Amino Acid ◽

Substrate Specificity ◽

Molecular Mechanisms ◽

Substrate Binding ◽

Binding Pocket ◽

Neutral Amino Acid ◽

Substrate Preference ◽

Structural Basis ◽

Substrate Binding Pocket

Despite having similar structures, each member of the heteromeric amino acid transporter (HAT) family shows exquisite preference for the exchange of certain amino acids. Substrate specificity determines the physiological function of each HAT and their role in human diseases. However, HAT transport preference for some amino acids over others is not yet fully understood. Using cryo–electron microscopy of apo human LAT2/CD98hc and a multidisciplinary approach, we elucidate key molecular determinants governing neutral amino acid specificity in HATs. A few residues in the substrate-binding pocket determine substrate preference. Here, we describe mutations that interconvert the substrate profiles of LAT2/CD98hc, LAT1/CD98hc, and Asc1/CD98hc. In addition, a region far from the substrate-binding pocket critically influences the conformation of the substrate-binding site and substrate preference. This region accumulates mutations that alter substrate specificity and cause hearing loss and cataracts. Here, we uncover molecular mechanisms governing substrate specificity within the HAT family of neutral amino acid transporters and provide the structural bases for mutations in LAT2/CD98hc that alter substrate specificity and that are associated with several pathologies.

Download Full-text

Aromatic Amino Acid Mutagenesis at the Substrate Binding Pocket ofYarrowia lipolyticaLipase Lip2 Affects Its Activity and Thermostability

The Scientific World JOURNAL ◽

10.1155/2014/382581 ◽

2014 ◽

Vol 2014 ◽

pp. 1-8 ◽

Cited By ~ 1

Author(s):

Guilong Wang ◽

Zimin Liu ◽

Li Xu ◽

Yunjun Yan

Keyword(s):

Amino Acid ◽

Aromatic Amino Acid ◽

Substrate Binding ◽

Binding Pocket ◽

Enzymatic Properties ◽

Site Directed Mutagenesis ◽

Wild Type ◽

Substrate Binding Pocket ◽

Significant Difference ◽

Amino Acid Mutations

The lipase2 fromYarrowia lipolytica(YLLip2) is a yeast lipase exhibiting high homologous to filamentous fungal lipase family. Though its crystal structure has been resolved, its structure-function relationship has rarely been reported. By contrast, there are two amino acid residues (V94 and I100) with significant difference in the substrate binding pocket of YLLip2; they were subjected to site-directed mutagenesis (SDM) to introduce aromatic amino acid mutations. Two mutants (V94W and I100F) were created. The enzymatic properties of the mutant lipases were detected and compared with the wild-type. The activities of mutant enzymes dropped to some extent towardsp-nitrophenyl palmitate (pNPC16) and their optimum temperature was 35°C, which was 5°C lower than that of the wild-type. However, the thermostability of I100F increased 22.44% after incubation for 1 h at 40°C and its optimum substrate shifted fromp-nitrophenyl laurate (pNPC12) top-nitrophenyl caprate (pNPC10). The above results demonstrated that the two substituted amino acid residuals have close relationship with such enzymatic properties as thermostability and substrate selectivity.

Download Full-text

Targeting Autophagy for Overcoming Resistance to Anti-EGFR Treatments

Cancers ◽

10.3390/cancers11091374 ◽

2019 ◽

Vol 11 (9) ◽

pp. 1374 ◽

Cited By ~ 7

Author(s):

Yoojung Kwon ◽

Misun Kim ◽

Hyun Suk Jung ◽

Youngmi Kim ◽

Dooil Jeoung

Keyword(s):

Protein Kinase ◽

Kinase Inhibitors ◽

Acquired Resistance ◽

Growth Factor Receptor ◽

Mapk Signaling ◽

Mitogen Activated Protein Kinase ◽

Cancer Drug ◽

Egfr Signaling ◽

Anti Cancer ◽

Mitogen Activated Protein

Epidermal growth factor receptor (EGFR) plays critical roles in cell proliferation, tumorigenesis, and anti-cancer drug resistance. Overexpression and somatic mutations of EGFR result in enhanced cancer cell survival. Therefore, EGFR can be a target for the development of anti-cancer therapy. Patients with cancers, including non-small cell lung cancers (NSCLC), have been shown to response to EGFR-tyrosine kinase inhibitors (EGFR-TKIs) and anti-EGFR antibodies. However, resistance to these anti-EGFR treatments has developed. Autophagy has emerged as a potential mechanism involved in the acquired resistance to anti-EGFR treatments. Anti-EGFR treatments can induce autophagy and result in resistance to anti-EGFR treatments. Autophagy is a programmed catabolic process stimulated by various stimuli. It promotes cellular survival under these stress conditions. Under normal conditions, EGFR-activated phosphoinositide 3-kinase (PI3K)/AKT serine/threonine kinase (AKT)/mammalian target of rapamycin (mTOR) signaling inhibits autophagy while EGFR/rat sarcoma viral oncogene homolog (RAS)/mitogen-activated protein kinase kinase (MEK)/mitogen-activated protein kinase (MAPK) signaling promotes autophagy. Thus, targeting autophagy may overcome resistance to anti-EGFR treatments. Inhibitors targeting autophagy and EGFR signaling have been under development. In this review, we discuss crosstalk between EGFR signaling and autophagy. We also assess whether autophagy inhibition, along with anti-EGFR treatments, might represent a promising approach to overcome resistance to anti-EGFR treatments in various cancers. In addition, we discuss new developments concerning anti-autophagy therapeutics for overcoming resistance to anti-EGFR treatments in various cancers.

Download Full-text

Crystal structure of steroid reductase SRD5A reveals conserved steroid reduction mechanism

Nature Communications ◽

10.1038/s41467-020-20675-2 ◽

2021 ◽

Vol 12 (1) ◽

Author(s):

Yufei Han ◽

Qian Zhuang ◽

Bo Sun ◽

Wenping Lv ◽

Sheng Wang ◽

...

Keyword(s):

Crystal Structure ◽

Biochemical Characterization ◽

Substrate Binding ◽

Binding Pocket ◽

Substrate Binding Pocket ◽

Transmembrane Segments ◽

Therapeutic Molecules ◽

Binding Cavity ◽

Immune System Regulation ◽

Mediated Reduction

AbstractSteroid hormones are essential in stress response, immune system regulation, and reproduction in mammals. Steroids with 3-oxo-Δ4 structure, such as testosterone or progesterone, are catalyzed by steroid 5α-reductases (SRD5As) to generate their corresponding 3-oxo-5α steroids, which are essential for multiple physiological and pathological processes. SRD5A2 is already a target of clinically relevant drugs. However, the detailed mechanism of SRD5A-mediated reduction remains elusive. Here we report the crystal structure of PbSRD5A from Proteobacteria bacterium, a homolog of both SRD5A1 and SRD5A2, in complex with the cofactor NADPH at 2.0 Å resolution. PbSRD5A exists as a monomer comprised of seven transmembrane segments (TMs). The TM1-4 enclose a hydrophobic substrate binding cavity, whereas TM5-7 coordinate cofactor NADPH through extensive hydrogen bonds network. Homology-based structural models of HsSRD5A1 and -2, together with biochemical characterization, define the substrate binding pocket of SRD5As, explain the properties of disease-related mutants and provide an important framework for further understanding of the mechanism of NADPH mediated steroids 3-oxo-Δ4 reduction. Based on these analyses, the design of therapeutic molecules targeting SRD5As with improved specificity and therapeutic efficacy would be possible.

Download Full-text