Efficacy and Tolerability of 14-Day Tegoprazan- versus Rabeprazole-Based Triple Therapy for Eradication of Helicobacter pylori: A Real-World Evidence Study.

Background/Aims: Tegoprazan, a new, fast, and strong potassium-competitive acid blocker, has been approved for the treatment of gastric acid-related diseases in Korea. However, real-world clinical data regarding this drug are scarce. We aimed to compare the Helicobacter pylori eradication rates of tegoprazan- and rabeprazole-based triple therapy. Methods: We retrospectively reviewed data from patients who received first-line treatment for H. pylori infection using tegoprazan- or rabeprazole-based triple therapy for 2 weeks (50 mg tegoprazan or 20 mg rabeprazole+1,000 mg amoxicillin+500 mg clarithromycin twice daily). The primary endpoint was the eradication rate as determined by intention-to-treat analysis. Results: Of the 677 patients included in our study, 344 and 333 received tegoprazan-based and rabeprazole-based triple therapy, respectively. The eradication rate from intention-to-treat analysis was 76.7% (95% confidence interval [CI], 72.1% to 81.0%) for tegoprazan-based triple therapy and 75.4% (95% CI, 70.5% to 79.8%) for rabeprazole-based triple therapy. There was no significant difference in the eradication rates between the two groups (p>0.999). Per-protocol analysis also revealed no significant difference between the eradication rates of the two groups (tegoprazan 83.4% [95% CI, 79.0% to 87.2%] vs rabeprazole 83.5% [79.0% to 87.4%], p>0.999). Furthermore, there was no significant difference in adverse event rates between the two groups (tegoprazan, 27.6%; rabeprazole, 25.8%; p=0.604). Conclusions: The eradication rate of tegoprazan-based triple therapy was similar to that of rabeprazole-based triple therapy. Further studies on the dose-escalation effect of tegoprazan for H. pylori eradication and the efficacy of tegoprazan in regimens other than conventional triple therapy are needed.

Characterization of an (R)-specific enoyl-CoA hydratase from Streptomyces sp. strain CFMR 7: A metabolic tool for enhancing the production of poly(3-hydroxybutyrate-co-3-hydroxyhexanoate).

Poly[(R)-3-hydroxybutyrate-co-(R)-3-hydroxyhexanoate] [P(3HB-co-3HHx)] has a high potential to serve as a commercial bioplastic due to its biodegradability, thermoplastic and mechanical properties. The properties of this copolymer are greatly affected by the composition of 3HHx monomer. One of the most efficient ways to modulate the composition of 3HHx monomer in P(3HB-co-3HHx) is by manipulating the (R)-3HHx-CoA monomer supply. In this study, a new (R)-specific enoyl-CoA hydratase originating from a non-PHA producer, Streptomyces sp. strain CFMR 7 (PhaJSs), was characterized and found to be effective in supplying 3HHx monomer during in vivo production of P(3HB-co-3HHx) copolymer. The P(3HB-co-3HHx) copolymer produced from the Cupriavidus necator transformant that harbors phaJSs, PHB-4/pBBR1-CBP-M-CPF4JSs, showed enhanced 3HHx incorporation of up to 11 mol% without affecting the P(3HB-co-3HHx) production when palm oil was used as the carbon source. In addition, both kcat and kcat/Km of PhaJSs were higher toward the C6 than the shorter C4 substrates, underscoring the preference for 3-hydroxyhexanoyl-CoA. These results suggest that PhaJSs has a significant ability to supply 3HHx monomers for PHA biosynthesis via ß-oxidation and can be applied for metabolic engineering of robust PHA-producing strains.

7-day versus 14-day tegoprazan-based triple therapy to treat Helicobacter pylori infection: Real-world evidence.

BACKGROUND AND AIM: Potassium-competitive acid blockers (P-CABs) can be used to eradicate Helicobacter pylori infection. We aimed to evaluate the impact of treatment duration (7 vs 14 days) on successful H. pylori eradication with P-CAB-based triple therapy in Korea, where clarithromycin resistance rate is high. METHODS: We retrospectively reviewed the data of patients who received first-line treatment for H. pylori infection with tegoprazan-based triple therapy (50 mg tegoprazan + 1000 mg amoxicillin + 500 mg clarithromycin twice daily for 1 or 2 weeks). The primary endpoint was the eradication rate in intention-to-treat (ITT) analysis. RESULTS: Of the 948 patients included in the study, 435 and 513 received 7-day and 14-day tegoprazan-based triple therapy, respectively. The eradication rate was higher in the 14-day therapy group than in the 7-day therapy group (ITT, 63.9%; 95% confidence interval [CI], 59.3-68.3%] vs 78.6% [95% CI, 74.9-81.9%], respectively, P < 0.001; per-protocol, 70.5% [95% CI, 65.8-74.8%] vs 85.1% [81.7-88.1%], respectively, P < 0.001). Overall adverse event rates did not differ between the two groups. Although six patients in the 14-day treatment group discontinued the prescribed medications due to adverse events, four of them (67%) discontinued the medication within 4 days. CONCLUSIONS: The 14-day tegoprazan-based triple therapy showed a superior eradication rate and acceptable adverse events compared with the 7-day tegoprazan-based triple therapy. A 14-day treatment regimen may be required when H. pylori infection is treated with tegoprazan-based triple therapy in regions with high clarithromycin resistance.

Tropical origins of the record-breaking 2020 summer rainfall extremes in East Asia.

The East Asian countries have experienced heavy rainfalls in boreal summer 2020. Here, we investigate the dynamical processes driving the rainfall extremes in East Asia during July and August. The Indian Ocean basin warming in June can be responsible for the anticyclonic anomalies in the western North Pacific (WNP), which modulate the zonally-elongated rainfalls in East Asia during July through an atmospheric Rossby wave train. In August, the East Asian rainfall increase is also related to the anticyclonic anomalies in the subtropical WNP, although it is located further north. The north tropical Atlantic warming in June partly contributes to the subtropical WNP rainfall decrease in August through a subtropical teleconnection. Then the subtropical WNP rainfall decrease drives the local anticyclonic anomalies that cause the rainfall increase in East Asia during August. The tropical Indian Ocean anomalously warmed in June and the subtropical WNP rainfall decreased in August 2020, which played a role in modulating the WNP anticyclonic anomalies. Therefore, the record-breaking rainfall extremes in East Asia that occurred during summer 2020 can be explained by the teleconnections associated with the tropical origins among the Indian, Pacific, and Atlantic Oceans and their interbasin interactions.

Structural insights into vesicle amine transport-1 (VAT-1) as a member of the NADPH-dependent quinone oxidoreductase family.

Vesicle amine transport protein-1 (VAT-1) has been implicated in the regulation of vesicular transport, mitochondrial fusion, phospholipid transport and cell migration, and is a potential target of anticancer drugs. Little is known about the molecular function of VAT-1. The amino acid sequence indicates that VAT-1 belongs to the quinone oxidoreductase subfamily, suggesting that VAT-1 may possess enzymatic activity in unknown redox processes. To clarify the molecular function of VAT-1, we determined the three-dimensional structure of human VAT-1 in the free state at 2.3 Å resolution and found that VAT-1 forms a dimer with the conserved NADPH-binding cleft on each protomer. We also determined the structure of VAT-1 in the NADP-bound state at 2.6 Å resolution and found that NADP binds the binding cleft to create a putative active site with the nicotine ring. Substrate screening suggested that VAT-1 possesses oxidoreductase activity against quinones such as 1,2-naphthoquinone and 9,10-phenanthrenequinone.

Crosstalk between HSPA5 arginylation and sequential ubiquitination leads to AKT degradation through autophagy flux.

AKT/PKB is downregulated by the ubiquitin-proteasome system (UPS), which plays a key role in cell survival and tumor progression in various types of cancer. The objective of this study was to determine the relationship between the sequential ubiquitination of lysine residues K284 to K214 in AKT and R-HSPA5 (the arginylated form of HSPA5), which contribute to the autophagic/lysosomal degradation of AKT when impaired proteasomal activity induces cellular stress. Results show that proteasome inhibitors (PIs) increased ATE1 (arginyltransferase 1)-mediated R-HSPA5 levels in a reactive oxygen species (ROS)-dependent manner. Further, binding of fully ubiquitinated AKT with R-HSPA5 induced AKT degradation via the autophagy-lysosome pathway. Specifically, the K48 (Lys48)-linked ubiquitinated form of AKT was selectively degraded in the lysosome with R-HSPA5. The deubiquitinase, USP7 (ubiquitin specific peptidase 7), prevented AKT degradation by inhibiting AKT ubiquitination via interaction with AKT. MUL1 (mitochondrial ubiquitin ligase activator of NFKB 1) also played a vital role in the lysosomal degradation of AKT by sequentially ubiquitinating AKT residues K284 to K214 for R-HSPA5-mediated autophagy. Consistent with this finding, despite HSPA5 arginylation, AKT was not degraded in mul1 KO cells. These results suggest that MUL1-mediated sequential ubiquitination of K284 to K214 may serve as a novel mechanism by which AKT is designated for lysosomal degradation. Moreover, binding of R-HSPA5 with fully ubiquitinated AKT is required for the autophagic/lysosomal degradation of AKT. Thus, modulating the MUL1-mediated non-proteasomal proteolysis mechanisms, such as sequential ubiquitination, may prove to be a novel therapeutic approach for cancer treatment.Abbreviations: AKT1: thymoma viral proto-oncogene 1; ATE1: arginyltransferase 1; ATG5: autophagy related 5; CASP3: caspase 3; EGFP: enhanced green fluorescent protein; GAPDH: glyceraldehyde-3-phosphate dehydrogenase; GSK3B; glycogen synthase kinase 3 beta; HA: hemagglutinin; HSPA5/GRP78/BIP: heat shock protein 5; LAMP1: lysosomal-associated membrane protein 1; MAP1LC3B: microtubule-associated protein 1 light chain 3 beta; MEF: mouse embryonic fibroblast; MUL1: mitochondrial ubiquitin ligase activator of NFKB1; NAC: N-acetylcysteine; NEK2: NIMA (never in mitosis gene a)-related expressed kinase 2; NH4Cl: ammonium chloride; PARP1: poly(ADP-ribose) polymerase family, member 1; PI: proteasome inhibitor; R-HSPA5: arginylated HSPA5; ROS: reactive oxygen species; SQSTM1: sequestome 1; Ub: ubiquitin; USP7: ubiquitin specific peptidase 7.

Asymmetric Open-Closed Dimer Mechanism of Polyhydroxyalkanoate Synthase PhaC.

Biodegradable polyester polyhydroxyalkanoate (PHA) is a promising bioplastic material for industrial use as a replacement for petroleum-based plastics. PHA synthase PhaC forms an active dimer to polymerize acyl moieties from the substrate acyl-coenzyme A (CoA) into PHA polymers. Here we present the crystal structure of the catalytic domain of PhaC from Chromobacterium sp. USM2, bound to CoA. The structure reveals an asymmetric dimer, in which one protomer adopts an open conformation bound to CoA, whereas the other adopts a closed conformation in a CoA-free form. The open conformation is stabilized by the asymmetric dimerization and enables PhaC to accommodate CoA and also to create the product egress path. The bound CoA molecule has its ß-mercaptoethanolamine moiety extended into the active site with the terminal SH group close to active center Cys291, enabling formation of the reaction intermediate by acylation of Cys291.

Non-Thermal Plasma Induces Antileukemic Effect Through mTOR Ubiquitination.

Non-thermal plasma (NTP) has been studied as a novel therapeutic tool for cancer that does not damage healthy cells. In this study, we show that NTP-treated solutions (NTS) can induce death in various leukemia cells through mechanistic target of rapamycin (mTOR) ubiquitination. Previously, we manufactured and demonstrated the efficacy of NTS in solid cancers. NTS did not exhibit any deleterious side effects, such as acute death or weight loss in nude mice. In the present study, NTS induced cell death in myeloid leukemia cells, including acute myeloid leukemia (AML) and chronic myeloid leukemia (CML). We found that mTOR was downregulated in NTS-treated cells via the ubiquitin-proteasome system (UPS). We also identified 'really interesting new gene' finger protein 126 (RNF126) as a novel binding protein for mTOR through protein arrays and determined the role of E3 ligase in NTS-induced mTOR ubiquitination. NTS-derived reactive oxygen species (ROS) affected RNF126 expression and lysosomal dysfunction. These findings suggest that NTS has potential antileukemic effects through RNF126-mediated mTOR ubiquitination with no deleterious side effects. Thus, NTS may represent a new therapeutic method for chemotherapy-resistant leukemia.

Author Correction: El Niño-Southern Oscillation complexity.

In this Review, the middle initial of author Kim M. Cobb was omitted. The original Review has been corrected online.

Association of time to colonoscopy after a positive fecal test result and fecal hemoglobin concentration with risk of advanced colorectal neoplasia.

BACKGROUND: We evaluated the risk of advanced colorectal neoplasia (ACRN) and colorectal cancer (CRC) according to time to colonoscopy after positive fecal immunochemical test (FIT), fecal hemoglobin concentration, and combination of both. METHODS: We analyzed the records of 2362 patients aged ≥50 years who underwent colonoscopy because of a positive FIT result through the National Cancer Screening Program of Korea. RESULTS: ACRN risk increased with increasing time to colonoscopy after a positive FIT (17.2%, 18.6%, 19.1%, 21.4%, and 27.2% in <30, 30-59, 60-149, 150-179, and ≥180 days; P = 0.034), and ACRN and CRC risk increased with increasing fecal hemoglobin concentration (ACRN, 13.2%, 16.9%, 18.5%, 23.2%, and 26.6%; CRC, 1.3%, 1.7%, 4.7%, 5.7%, and 12.8% with 100-200, 200-300, 300-500, 500-1000, and ≥1000 ng Hb/mL; both P < 0.001). Even after adjusting for confounders, follow-up after 180 days tended to be associated with a higher ACRN risk (adjusted odds ratio, 1.73; 95% confidence interval [CI], 0.91-3.27), compared with follow-up colonoscopy at <30 days, and fecal hemoglobin 500-1000, and ≥1000 ng Hb/mL were associated with a significantly higher ACRN and CRC risk, compared with 100-200 ng Hb/mL. Moreover, the group with ≥180 days and ≥1000 ng Hb/mL had a much higher CRC risk compared with the group with <180 days and <1000 ng Hb/mL (12.45-fold; 95% CI, 3.73-41.57). CONCLUSIONS: Patients with positive FIT results, especially those with higher fecal hemoglobin levels, should undergo timely follow-up colonoscopy.

A Randomized Controlled Trial Comparing Colonoscopic Enema With Additional Oral Preparation as a Salvage for Inadequate Bowel Cleansing Before Colonoscopy.

GOALS: The goal of this study was to evaluate the noninferiority of colonoscopic enema to additional oral preparation in salvage bowel cleansing for inadequate preparation for a morning colonoscopy. BACKGROUND: Colonoscopic enema, administering additional cathartics into the right colon through the colonoscope accessory channel, is suggested to rescue poor bowel preparation for a colonoscopy but lacking comparative study. STUDY: In this prospective, randomized, actively-controlled, parallel group, noninferiority trial, consecutive outpatients and health checkup recipients aged from 19 to 70 years with inappropriate bowel preparation during an elective colonoscopy were enrolled to receive either a colonoscopic enema of 1 L polyethylene glycol (PEG) (enema group) or additional oral intake of 2 L PEG (oral group). The primary endpoint was the proportion of adequate bowel preparation evaluated using the Boston Bowel Preparation Scale. RESULTS: Overall, 131 participants were randomized. Adequate bowel preparation was achieved in 53% (35/66) of the enema group, which was significantly inferior to the oral group (81.5%; 53/67) with a difference of -28.5% (95% confidence interval, -44.1, -12.9; P=0.001). The largest difference in the proportion of adequate bowel preparation was observed in the right colon (57.8% in the enema group vs. 86.9% in the oral group; P<0.001), followed by the transverse colon (85.9% vs. 98.4%; P=0.017) and the left colon (90.6% vs. 96.7%; P=0.274). CONCLUSIONS: The colonoscopic enema of 1 L PEG was inferior to the additional oral ingestion of 2 L PEG regarding efficacy as a salvage bowel preparation in adults with inadequate bowel cleansing for colonoscopy.

GST Pull-Down Assay to Measure Complex Formations.

The GST pull-down assay is an intuitive and fast in vitro method for analyzing protein-protein or protein-ligand interactions and is comprised of a "bait" which is a GST-fused protein expressed in E. coli host or a baculovirus expression system and a "prey" which comprises putative binding partner protein(s) or other ligand molecule(s). This method is suitable for examining the direct interaction between two purified proteins and estimating the extent of the affinity.

El Niño-Southern Oscillation complexity.

El Niño events are characterized by surface warming of the tropical Pacific Ocean and weakening of equatorial trade winds that occur every few years. Such conditions are accompanied by changes in atmospheric and oceanic circulation, affecting global climate, marine and terrestrial ecosystems, fisheries and human activities. The alternation of warm El Niño and cold La Niña conditions, referred to as the El Niño-Southern Oscillation (ENSO), represents the strongest year-to-year fluctuation of the global climate system. Here we provide a synopsis of our current understanding of the spatio-temporal complexity of this important climate mode and its influence on the Earth system.

HSPA5 negatively regulates lysosomal activity through ubiquitination of MUL1 in head and neck cancer.

HSPA5/GRP78/BiP plays an important role in cell survival or tumor progression. For these reasons, HSPA5 is an emerging therapeutic target in cancer development. Here we report that HSPA5 contributes to head and neck cancer (HNC) survival via maintenance of lysosomal activity; however, a nonthermal plasma (NTP, considered as a next-generation cancer therapy)-treated solution (NTS) inhibits HNC progression through HSPA5-dependent alteration of lysosomal activity. HSPA5 prevents NTS-induced lysosome inhibition through lysosomal-related proteins or regulation of gene expression. However, NTS-induced MUL1/MULAN/GIDE/MAPL (mitochondrial ubiquitin ligase activator of NFKB 1) leads to downregulation of HSPA5 via K48-linked ubiquitination at the lysine 446 (K446) residue. MUL1 knockdown hinders NTS-induced lysosome inhibition or cytotoxicity through the reduction of HSPA5 ubiquitination in HNC cells. While MUL1 was suppressed, HSPA5 was overexpressed in tissues of HNC patients. NTS strongly inhibited HNC progression via alterations of expression of MUL1 and HSPA5, in vivo in a xenograft model. However, NTS did not induce inhibition of tumor progression or HSPA5 reduction in MUL1 knockout (KO) HNC cells which were generated by CRISPR/Cas9 system. The data provide compelling evidence to support the idea that the regulation of the MUL1-HSPA5 axis can be a novel strategy for the treatment of HNC.

Molecular Characterization of Viral Responsive Protein 15 and Its Possible Role in Nuclear Export of Virus in Black Tiger Shrimp Penaeus monodon.

A viral responsive protein 15 from Penaeus monodon (PmVRP15) has been reported to be important for white spot syndrome virus (WSSV) infection in vivo. This work aims to characterize PmVRP15 and investigate its possible role in nuclear import/export of the virus. Circular dichroism spectra showed that PmVRP15 contains high helical contents (82%). Analytical ultracentrifugation suggested that PmVRP15 could possibly form oligomers in solution. A subcellular fractionation study showed that PmVRP15 was found in heavy and light membrane fractions, indicating that PmVRP15 may be associated with endoplasmic reticulum. Double-stranded RNAi-mediated knockdown of PmVRP15 gene expression in vitro showed no effect on WSSV copy number in whole hemocyte cells. However, PmVRP15 silencing resulted in an accumulation of WSSV DNA in the nucleus of PmVRP15-silenced hemocytes. Immunofluorescence confocal microscopy showed that PmVRP15 knockdown hemocytes had a much lower level of VP28 (WSSV envelope protein), in comparison to that in the control. It is likely that PmVRP15 may play a role in viral nuclear egress.

Structure of polyhydroxyalkanoate (PHA) synthase PhaC from Chromobacterium sp. USM2, producing biodegradable plastics.

Polyhydroxyalkanoate (PHA) is a promising candidate for use as an alternative bioplastic to replace petroleum-based plastics. Our understanding of PHA synthase PhaC is poor due to the paucity of available three-dimensional structural information. Here we present a high-resolution crystal structure of the catalytic domain of PhaC from Chromobacterium sp. USM2, PhaC Cs -CAT. The structure shows that PhaC Cs -CAT forms an α/ß hydrolase fold comprising α/ß core and CAP subdomains. The active site containing Cys291, Asp447 and His477 is located at the bottom of the cavity, which is filled with water molecules and is covered by the partly disordered CAP subdomain. We designated our structure as the closed form, which is distinct from the recently reported catalytic domain from Cupriavidus necator (PhaC Cn -CAT). Structural comparison showed PhaC Cn -CAT adopting a partially open form maintaining a narrow substrate access channel to the active site, but no product egress. PhaC Cs -CAT forms a face-to-face dimer mediated by the CAP subdomains. This arrangement of the dimer is also distinct from that of the PhaC Cn -CAT dimer. These findings suggest that the CAP subdomain should undergo a conformational change during catalytic activity that involves rearrangement of the dimer to facilitate substrate entry and product formation and egress from the active site.

FOXO3 induces ubiquitylation of AKT through MUL1 regulation.

AKT (also known as protein kinase B, PKB) plays an important role in cell survival or tumor progression. For these reasons, AKT is an emerging target for cancer therapeutics. Previously our studies showed that mitochondrial E3 ubiquitin protein ligase 1 (MUL1, also known as MULAN/GIDE/MAPL) is suppressed in head and neck cancer (HNC) and acts as negative regulator against AKT. However, the MUL1 regulatory mechanisms remain largely unknown. Here we report that cisplatin (CDDP) induces thyroid cancer cell death through MUL1-AKT axis. Specifically, CDDP-induced MUL1 leads to ubiquitylation of active form of AKT. We also observed that the role of forkhead box O3 (FOXO3) is pivotal in CDDP-induced MUL1 regulation. FOXO3 knock-downed cells show resistance against CDDP-mediated MUL1-AKT axis. CDDP-mediated intracellular ROS increment plays an important role in FOXO3-MUL1-AKT signal pathway. The data provide compelling evidence to support the idea that the regulation of FOXO3-MUL1-AKT axis can be a novel strategy for the treatment of HNC with CDDP.

Structural basis for autoinhibition and its relief of MOB1 in the Hippo pathway.

MOB1 protein is a key regulator of large tumor suppressor 1/2 (LATS1/2) kinases in the Hippo pathway. MOB1 is present in an autoinhibited form and is activated by MST1/2-mediated phosphorylation, although the precise mechanisms responsible for autoinhibition and activation are unknown due to lack of an autoinhibited MOB1 structure. Here, we report on the crystal structure of full-length MOB1B in the autoinhibited form and a complex between the MOB1B core domain and the N-terminal regulation (NTR) domain of LATS1. The structure of full-length MOB1B shows that the N-terminal extension forms a short ß-strand, the SN strand, followed by a long conformationally flexible positively-charged linker and α-helix, the Switch helix, which blocks the LATS1 binding surface of MOB1B. The Switch helix is stabilized by ß-sheet formation of the SN strand with the S2 strand of the MOB1 core domain. Phosphorylation of Thr12 and Thr35 residues structurally accelerates dissociation of the Switch helix from the LATS1-binding surface by the "pull-the-string" mechanism, thereby enabling LATS1 binding.

Mitochondrial E3 Ubiquitin Protein Ligase 1 Mediates Cigarette Smoke-Induced Endothelial Cell Death and Dysfunction.

By virtue of the critical roles of Akt in vascular endothelial cell (EC) survival and function, cigarette smoke-induced Akt reduction may contribute to EC death and dysfunction in smokers' lungs. One of the negative Akt regulatory mechanisms is K48-linked Akt ubiquitination and subsequent proteasomal degradation. Here, we assessed the involvement of mitochondrial E3 ubiquitin protein ligase 1 (MUL1), recently revealed as a novel Akt ubiquitin E3 ligase, in cigarette smoke-induced Akt ubiquitination and its contribution to pulmonary EC death and dysfunction. In human lung microvascular ECs (HLMVECs), cigarette smoke extract (CSE) noticeably elevated MUL1 expression and K48-linked Akt ubiquitination, whereas Akt, p-Akt, eNOS, and p-eNOS levels were decreased. MUL1 knockdown suppressed CSE-induced Akt ubiquitination/degradation and cytoplasmic reductions of Akt and p-Akt. Furthermore, MUL1 knockdown attenuated reductions of eNOS and p-eNOS and alleviated EC survival, migration, and tube formation in the presence of CSE exposure. In addition, overexpression of K284R Akt, a mutant for a MUL1-ubiquitination site, produced similar effects. In HLMVECs exposed to CSE, Akt-MUL1 interaction was increased in coimmunoprecipitation and in situ proximity ligation assays. Similarly, the proximity ligation assay signals were elevated in rat lungs exposed to cigarette smoke for 3 months, during which Mul1 levels were noticeably increased. Finally, we found that CSE-mediated MUL1 induction in HLMVECs is mediated by retinoic acid receptor-related orphan receptor α. Taken together, these data suggest that cigarette smoke-induced MUL1 elevation mediates Akt ubiquitination/degradation, potentially leading to pulmonary EC death and functional impairment.

Non-thermal plasma induces AKT degradation through turn-on the MUL1 E3 ligase in head and neck cancer.

Recent research on non-thermal plasma (NTP, an ionized gas) has identified it as a novel cancer therapeutic tool. However, the molecular mechanism remains unclear. In this study, we demonstrated NTP induced cell death of head and neck cancer (HNC) through the AKT ubiquitin-proteasome system. NTP increased the gene expression of mitochondrial E3 ubiquitin protein ligase 1 (MUL1), an E3 ligase for AKT, and NTP-induced HNC cell death was prevented by MUL1 siRNA. We also showed that MUL1 inhibited the level of AKT and p-AKT and MUL1 expression was increased by NTP-induced ROS. Furthermore, we optimized and manufactured a new type of NTP, a liquid type of NTP (LTP). In syngeneic and xenograft in vivo tumor models, LTP inhibited tumor progression by increasing the MUL1 level and reducing p-AKT levels, indicating that LTP also has an anti-cancer effect through the same mechanism as that of NTP. Taken together, our results suggest that NTP and LTP have great potential for HNC therapy.