The extracellular signal‐regulated kinase (ERK) signaling pathway is essential for cell proliferation and is frequently deregulated in human tumors such as melanoma. Melanoma remains incurable ...despite the use of conventional chemotherapy; consequently, development of new therapeutic agents for melanoma is highly desirable. Here, we carried out a chemical genetic screen using a fission yeast phenotypic assay and showed that ACA‐28, a synthetic derivative of 1′‐acetoxychavicol acetate (ACA), which is a natural ginger compound, effectively inhibited the growth of melanoma cancer cells wherein ERK MAPK signaling is hyperactivated due to mutations in the upstream activating regulators. ACA‐28 more potently inhibited the growth of melanoma cells than did the parental compound ACA. Importantly, the growth of normal human epidermal melanocytes (NHEM) was less affected by ACA‐28 at the same 50% inhibitory concentration. In addition, ACA‐28 specifically induced apoptosis in NIH/3T3 cells which were oncogenically transformed with human epidermal growth factor receptor‐2 (HER2/ErbB2), but not in the parental cells. Notably, the ACA‐28‐induced apoptosis in melanoma and HER2‐transformed cells was abrogated when ERK activation was blocked with a specific MEK inhibitor U0126. Consistently, ACA‐28 more strongly stimulated ERK phosphorylation in melanoma cells, as compared in NHEM. ACA‐28 might serve as a promising seed compound for melanoma treatment.
Our chemical genetic screen identified ACA‐28, a 1′‐acetoxychavicol acetate (ACA) analogue compound as a MAPK signaling modulator. ACA‐28 induced apoptosis in melanoma and NIH/3T3 cells oncogenically transformed with HER2//ErbB2 by stimulating ERK phosphorylation. ERK inhibition antagonized the ACA‐28‐induced apoptosis and cytotoxicity.
The mitogen-activated protein kinase (MAPK) cascade is a highly conserved signaling module composed of MAPK kinase kinases (MAPKKKs), MAPK kinases (MAPKK) and MAPKs. The MAPKKK Mkh1 is an initiating ...kinase in Pmk1 MAPK signaling, which regulates cell integrity in fission yeast (Schizosaccharomyces pombe). Our genetic screen for regulators of Pmk1 signaling identified Shk1 kinase binding protein 5 (Skb5), an SH3-domain-containing adaptor protein. Here, we show that Skb5 serves as an inhibitor of Pmk1 MAPK signaling activation by downregulating Mkh1 localization to cell tips through its interaction with the SH3 domain. Consistent with this, the Mkh1(3PA) mutant protein, with impaired Skb5 binding, remained in the cell tips, even when Skb5 was overproduced. Intriguingly, Skb5 needs Mkh1 to localize to the growing ends as Mkh1 deletion and disruption of Mkh1 binding impairs Skb5 localization. Deletion of Pck2, an upstream activator of Mkh1, impaired the cell tip localization of Mkh1 and Skb5 as well as the Mkh1-Skb5 interaction. Interestingly, both Pck2 and Mkh1 localized to the cell tips at the G1/S phase, which coincided with Pmk1 MAPK activation. Taken together, Mkh1 localization to cell tips is important for transmitting upstream signaling to Pmk1, and Skb5 spatially regulates this process.
A study on 33 cases of deep neck abscess Kubota, Akinobu; Satoh, Ryosuke; Ishida, Yoshiya ...
Journal of Immunology, Allergy and Infection in Otorhinolaryngology,
2022, Volume:
2, Issue:
2
Journal Article
Open access
Deep neck abscess is a life-threatening disease that results in the formation of abscess within neck spaces due to bacterial infection in tonsils, mandibular teeth, or salivary glands. A ...retrospective study was conducted using the data on 33 patients diagnosed with the deep neck abscess (25 males and 8 females; age range, 0–99 years; median, 61 years) between 2010 and 2020. The median duration from the onset of symptoms to the first visit was 3 days (range, 1–7 days). Five of 33 (15.2%) patients had diabetes. The median white blood cell count and serum C-reactive protein level on day 1 of hospitalization were 13,940/μl (range, 7,100–34,670/μl) and 18.37 mg/dl (range, 1.26–36.5 mg/dl), respectively. Computed tomography (CT) revealed neck abscess involved in six or more spaces in eight (24.2%) patients and extension into the neck spaces under the hyoid bone in 21 (63.6%) patients. A total of 13 (39.3%) patients with severe laryngeal edema required tracheotomy. Bacterial examination of pus obtained from the abscess indicated the presence of both Streptococcus anginosus group (SAG) and anaerobic bacteria in 14 (42.4%) patients. The number of patients with extension of abscess into the neck spaces under the hyoid bone, neck abscess in six or more spaces, and the presence of both SAG and anaerobic bacteria was significantly higher in the tracheostomy group (p=0.004, p=0.005, and p=0.007, respectively). The number of patients with extension of abscess into the neck spaces under the hyoid bone, and the presence of both SAG and anaerobic bacteria were significantly correlated with the longer duration of hospitalization (p=0.02, and p=0.02, respectively). These results indicated that evaluation of the involved spaces using CT and detection of SAG and anaerobic bacteria could contribute to the extension of hospitalization.
Rapamycin and its derivatives have now emerged as an attractive therapeutic strategy with both immunosuppressant and antitumor properties. In addition, rapamycin has been proposed as a calorie ...restriction mimetic to extend the life span of various organisms. The fission yeast Schizosaccharomyces pombe (S. pombe) serves as a valuable genetic model system to study the mechanism(s) of drug action as well as to determine genetic contexts associated with drug sensitivity or resistance. Here, we identified genes that when deleted modulate the rapamycin‐sensitive strains in S. pombe. We carried out a chemical genomics screen for rapamycin‐sensitive mutants using the genome‐deletion library which covers 95.3% of all nonessential fission yeast genes and confirmed 59 genes to be rapamycin sensitive. Gene Ontology (GO) enrichment analysis showed that strains sensitive to rapamycin are highly enriched in processes regulating tRNA modification and mitochondria as well as other ontologies, including cellular metabolic process, chromatin organization, cell cycle, signaling, translation, transport and other cellular processes. Analysis also showed that components of the Elongator complex are overrepresented in the sensitive strains. Here, the data obtained will provide valuable information for speculation on the actions of rapamycin as well as on TORC signaling, thereby presenting a strategy to enhance sensitivity to rapamycin.
Rice lines with enhanced ADPglc synthesis and import into amyloplasts reveal additional barriers within the stroma that restrict maximum carbon flow into starch.
Previous studies showed that efforts ...to further elevate starch synthesis in rice (
Oryza sativa
) seeds overproducing ADP-glucose (ADPglc) were prevented by processes downstream of ADPglc synthesis. Here, we identified the major ADPglc transporter by studying the
shrunken3
locus of the EM1093 rice line, which harbors a mutation in the BRITTLE1 (BT1) adenylate transporter (
OsBt1
) gene. Despite containing elevated ADPglc levels (approximately 10-fold) compared with the wild-type, EM1093 grains are small and shriveled due to the reduction in the amounts and size of starch granules. Increases in ADPglc levels in EM1093 were due to their poor uptake of ADP-
14
Cglc by amyloplasts. To assess the potential role of BT1 as a rate-determining step in starch biosynthesis, the maize
ZmBt1
gene was overexpressed in the wild-type and the GlgC (CS8) transgenic line expressing a bacterial
glgC-TM
gene. ADPglc transport assays indicated that transgenic lines expressing ZmBT1 alone or combined with GlgC exhibited higher rates of transport (approximately 2-fold), with the GlgC (CS8) and GlgC/ZmBT1 (CS8/AT5) lines showing elevated ADPglc levels in amyloplasts. These increases, however, did not lead to further enhancement in seed weights even when these plant lines were grown under elevated CO
2
. Overall, our results indicate that rice lines with enhanced ADPglc synthesis and import into amyloplasts reveal additional barriers within the stroma that restrict maximum carbon flow into starch.
Pmk1, a fission yeast homologue of mammalian
ERK MAPK
, regulates cell wall integrity, cytokinesis,
RNA
granule formation and ion homeostasis. Our screen for
vic
(viable in the presence of ...immunosuppressant and chloride ion) mutants identified regulators of the Pmk1
MAPK
signaling, including Cpp1 and Rho2, based on the genetic interaction between calcineurin and Pmk1
MAPK
. Here, we identified the
vic2‐1
mutants carrying a mis‐sense mutation in the
cwg2
+
gene encoding a beta subunit of geranylgeranyltransferase I (
GGT
ase I), which participates in the post‐translational C‐terminal modification of several small
GTP
ases, allowing their targeting to the membrane. Analysis of the
vic2‐1
/
cwg2‐v2
mutant strain showed that the localization of Rho1, Rho4, Rho5 and Cdc42, both at the plasma and vacuolar membranes, was impaired in the
vic2‐1
/
cwg2‐v2
mutant cells. In addition, Rho4 and Rho5 deletion cells exhibited the
vic
phenotype and cell wall integrity defects, shared phenotypes among the components of the Pmk1
MAPK
pathway. Consistently, the phosphorylation of Pmk1
MAPK
on heat shock was decreased in the
cwg2‐v2
mutants, and
rho4
‐ and
rho5
‐null cells. Moreover, Rho4 and Rho5 associate with Pck1/Pck2. Possible roles of Cwg2, Rho4 and Rho5 in the Pmk1 signaling will be discussed.
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