Ras gene mutation and/or overexpression are drivers in the progression of cancers, including colorectal cancer. Blocking the Ras signaling has become a significant strategy for cancer therapy. ...Previously, we constructed a recombinant scFv, RGD-p21Ras-scFv by linking RGD membrane-penetrating peptide gene with the anti-p21Ras scFv gene. Here, we expressed prokaryotically RGD-p21Ras-scFv on a pilot scale, then investigated the anti-tumor effect and the mechanism of blocking Ras signaling.
The E. coli bacteria which could highly express RGD-p21Ras-scFv was screened and grown in 100 L fermentation tank to produce RGD-p21Ras-scFv on optimized induced expression conditions. The scFv was purified from E. coli bacteria using His Ni-NTA column. ELISA was adopted to test the immunoreactivity of RGD-p21Ras-scFv against p21Ras proteins, and the IC50 of RGD-p21Ras-scFv was analyzed by CCK-8. Immunofluorescence colocalization and pull-down assays were used to determine the localization and binding between RGD-p21Ras-scFv and p21Ras. The interaction forces between RGD-p21Ras-scFv and p21Ras after binding were analyzed by molecular docking, and the stability after binding was determined by molecular dynamics simulations. p21Ras-GTP interaction was detected by Ras pull-down. Changes in the MEK-ERK /PI3K-AKT signaling paths downstream of Ras were detected by WB assays. The anti-tumor activity of RGD-p21Ras-scFv was investigated by nude mouse xenograft models.
The technique of RGD-p21Ras-scFv expression on a pilot scale was established. The wet weight of the harvested bacteria was 31.064 g/L, and 31.6 mg RGD-p21Ras-scFv was obtained from 1 L of bacterial medium. The purity of the recombinant antibody was above 85%, we found that the prepared on a pilot scale RGD-p21Ras-scFv could penetrate the cell membrane of colon cancer cells and bind to p21Ras, then led to reduce of p21Ras-GTP (active p21Ras). The phosphorylation of downstream effectors MEK-ERK /PI3K-AKT was downregulated. In vivo antitumor activity assays showed that the RGD-p21Ras-scFv inhibited the proliferation of colorectal cancer cell lines.
RGD-p21Ras-scFv prokaryotic expressed on pilot-scale could inhibited Ras-driven colorectal cancer growth by partially blocking p21Ras-GTP and might be able to be a hidden therapeutic antibody for treating RAS-driven tumors.
SUMMARY
Chloroplasts play a crucial role in plant growth and fruit quality. However, the molecular mechanisms of chloroplast development are still poorly understood in fruits. In this study, we ...investigated the role of the transcription factor SlBEL2 (BEL1‐LIKE HOMEODOMAIN 2) in fruit of Solanum lycopersicum (tomato). Phenotypic analysis of SlBEL2 overexpression (OE‐SlBEL2) and SlBEL2 knockout (KO‐SlBEL2) plants revealed that SlBEL2 has the function of inhibiting green shoulder formation in tomato fruits by affecting the development of fruit chloroplasts. Transcriptome profiling revealed that the expression of chloroplast‐related genes such as SlGLK2 and SlLHCB1 changed significantly in the fruit of OE‐SlBEL2 and KO‐SlBEL2 plants. Further analysis showed that SlBEL2 could not only bind to the promoter of SlGLK2 to inhibit its transcription, but also interacted with the SlGLK2 protein to inhibit the transcriptional activity of SlGLK2 and its downstream target genes. SlGLK2 knockout (KO‐SlGLK2) plants exhibited a complete absence of the green shoulder, which was consistent with the fruit phenotype of OE‐SlBEL2 plants. SlBEL2 showed an expression gradient in fruits, in contrast with that reported for SlGLK2. In conclusion, our study reveals that SlBEL2 affects the formation of green shoulder in tomato fruits by negatively regulating the gradient expression of SlGLK2, thus providing new insights into the molecular mechanism of fruit green shoulder formation.
Significance Statement
Chloroplasts play a crucial role in plant growth and fruit quality, but the molecular mechanisms underlying chloroplast development in fruits remain poorly understood. Here, our study reveals that SlBEL2 is expressed in a gradient in tomato fruits and affects the formation of the green shoulder in fruits by regulating chloroplast development, which provides new insights into the molecular mechanism of green shoulder formation in fruits.
Calcium alginate (Ca-Alg) is a novel target product for recovering alginate from aerobic granular sludge. A novel Ca-Alg production method was proposed herein where Ca-Alg was formed in a sodium ...alginate (SA) feed solution (FS) and concentrated via forward osmosis (FO) with Ca
reverse osmosis using a draw solution of CaCl
. An abnormal reverse solute diffusion was observed, with the average reverse solute flux (RSF) decreasing with increasing CaCl
concentrations, while the average RSF increased with increasing alginate concentrations. The RSF of Ca
in FS decreased continuously as the FO progressed, using 1.0 g/L SA as the FS, while it increased initially and later decreased using 2.0 and 3.0 g/L SA as the FS. These results were attributed to the Ca-Alg recovery production (CARP) formed on the FO membrane surface on the feed side, and the percentage of Ca
in CARP to total Ca
reverse osmosis reached 36.28%. Scanning electron microscopy and energy dispersive spectroscopy also verified CARP existence and its Ca
content. The thin film composite FO membrane with a supporting polysulfone electrospinning nanofiber membrane layer showed high water flux and RSF of Ca
, which was proposed as a novel FO membrane for Ca-Alg production via the FO process with Ca
reverse diffusion. Four mechanisms including molecular sieve role, electrification of colloids, osmotic pressure of ions in CARP, and FO membrane structure were proposed to control the Ca-Alg production. Thus, the results provide further insights into Ca-Alg production via FO along with Ca
reverse osmosis.
Estrogen receptor β (ERβ) has been reported to play an anti-cancer role in breast cancer, but the regulatory mechanism by which ERβ exerts this effect is not clear. Claudin-6 (CLDN6), a tight ...junction protein, acts as a tumor suppressor gene in breast cancer. Our previous studies have found that 17β-estradiol (E2) induces CLDN6 expression and inhibits MCF-7 cell migration and invasion, but the underlying molecular mechanisms are still unclear. In this study, we aimed to investigate the role of ERβ in this process and the regulatory mechanisms involved.
Polymerase chain reaction (PCR) and western blot were used to characterize the effect of E2 on the expression of CLDN6 in breast cancer cells. Chromatin immunoprecipitation (ChIP) assays were carried out to confirm the interaction between ERβ and CLDN6. Dual luciferase reporter assays were used to detect the regulatory role of ERβ on the promoter activity of CLDN6. Wound healing and Transwell assays were used to examine the migration and invasion of breast cancer cells. Western blot, immunofluorescence and transmission electron microscopy (TEM) were performed to detect autophagy. Xenograft mouse models were used to explore the regulatory effect of the CLDN6-beclin1 axis on breast cancer metastasis. Immunohistochemistry (IHC) was used to detect ERβ/CLDN6/beclin1 expression in breast cancer patient samples.
Here, E2 upregulated the expression of CLDN6, which was mediated by ERβ. ERβ regulated CLDN6 expression at the transcriptional level. ERβ inhibited the migration and invasion of breast cancer cells through CLDN6. Interestingly, this effect was associated with CLDN6-induced autophagy. CLDN6 positively regulated the expression of beclin1, which is a key regulator of autophagy. Beclin1 knockdown reversed CLDN6-induced autophagy and the inhibitory effect of CLDN6 on breast cancer metastasis. Moreover, ERβ and CLDN6 were positively correlated, and the expression of CLDN6 was positively correlated with beclin1 in breast cancer tissues.
Overall, this is the first study to demonstrate that the inhibitory effect of ERβ on the migration and invasion of breast cancer cells was mediated by CLDN6, which induced the beclin1-dependent autophagic cascade.
The aim of this study was to study the molecular characteristics of Trichinella spiralis galectin (Tsgal) and interactions between Tsgal and host's intestinal epithelial cells (IECs). The functional ...domain of Tsgal was cloned and expressed in an E. coli system. The Tsgal was 97.1% identity to the galectin of T. nativa and 20.8% identity to the galectin-8 of humans. Conserved domain analysis revealed that Tsgal belongs to TR-type galectin and has two carbon recognized domain. The rTsgal with 29.1 kDa could be recognized by T. spiralis-infected mice at 42 days post-infection (dpi). The transcription and expression of Tsgal gene was detected by RT-PCR and Western blotting in all T. spiralis developmental stages (intestinal infective larvae, adult worms, newborn larvae, and muscle larvae). The IFA results revealed that Tsgal was mainly located at the cuticles and stichosomes of T. spiralis larvae (ML, IIL and NBL). The rTsgal had hemagglutinating function for erythrocytes from human, rabbit and mouse. The results of Far Western blot and confocal microscopy indicated there was specific binding between rTsgal and IECs, and the binding was located the membrane and cytoplasm of the IECs. Out of four sugars (sucrose, glucose, lactose and maltose), only lactose was able to inhibit the rTsgal agglutinating role for human type B erythrocytes. Moreover, the rTsgal could promote the larval invasion of IECs, while the anti-rTsgal serum inhibited the larval invasion. These results demonstrated that Tsgal might participate in the T. spiralis invasion of intestinal epithelium in early infection stage.
Some studies have proved that both acupuncture and moxibustion are very effective for the treatment of CAG. However, little is known about therapeutic mechanism of electro-acupuncture and moxibustion ...on CAG as well as the difference between them. On the other hand, metabolomics is a 'top-down' approach to understand metabolic changes of organisms caused by disease or interventions in holistic context, which consists with the holistic thinking of electro-acupuncture and moxibustion treatment. In this study, the difference of therapeutic mechanism between electro-acupuncture and moxibustion on CAG rats was investigated by a
H NMR-based metabolomics analysis of multiple biological samples (serum, stomach, cerebral cortex and medulla) coupled with pathological examination and molecular biological assay. For all sample types, both electro-acupuncture and moxibustion intervention showed beneficial effects by restoring many CAG-induced metabolic changes involved in membrane metabolism, energy metabolism and function of neurotransmitters. Notably, the moxibustion played an important role in CAG treatment mainly by regulating energy metabolism in serum, while main acting site of electro-acupuncture treatment was nervous system in stomach and brain. These findings are helpful to facilitate the therapeutic mechanism elucidating of electro-acupuncture and moxibustion on CAG rats. Metabolomics is promising in mechanisms study for traditional Chinese medicine (TCM).
The recycling of extracellular polymeric substances (EPSs) from excess sludge in wastewater treatment plants has received increasing attention in recent years. Although membrane separation has great ...potential for use in EPS concentration and recovery, conventional membranes tend to exhibit low water flux and high energy consumption. Herein, electrospun nanofiber membranes (ENMs) were fabricated using polyvinylidene fluoride (PVDF) and used for the recovery of EPSs extracted from the excess sludge using the cation exchange resin (CER) method. The fabricated ENM containing 14 wt.% PVDF showed excellent properties, with a high average water flux (376.8 L/(m
·h)) and an excellent EPS recovery rate (94.1%) in the dead-end filtration of a 1.0 g/L EPS solution at 20 kPa. The ENMs displayed excellent mechanical strength, antifouling properties, and high reusability after five recycles. The filtration pressure had a negligible effect on the average EPS recovery rate and water flux. The novel dead-end filtration with an EPS filter cake on the ENM surface was effective in removing heavy-metal ions, with the removal rates of Pb
, Cu
, and Cr
being 89.5%, 73.5%, and 74.6%, respectively. These results indicate the potential of nanofiber membranes for use in effective concentration and recycling of EPSs via membrane separation.
•High-CO2 treatment delayed ripening and senescence of postharvest strawberry fruit.•lncRNA-mRNA regulation module is vital to strawberry fruit ripening and senescence.•Delayed strawberry fruit ...ripening and senescence by high-CO2 is related to lncRNA.
Strawberry fruit is susceptible to postharvest spoilage with a short shelf-life, and high-CO2 treatment is an effective method to maintain the postharvest storage quality of fruit and vegetables. The aim of this study is to investigate the molecular mechanisms of high-CO2 treatment delaying the ripening and senescence of strawberry fruit after harvest. The results of this study showed that high-CO2 treatment delayed the softening and anthocyanin accumulation of strawberry fruit during storage. Transcriptome combined with long non-coding RNA (lncRNA) analysis revealed that ripening and senescence-related genes involved in abscisic acid (ABA) metabolism, cell wall degradation and anthocyanin accumulation could be regulated as potential targets by lncRNAs. Under high-CO2 treatment conditions, the expression levels of a large number of lncRNAs were altered, thereby affecting the expression patterns of downstream ripening and senescence-related target genes and resulting in the delay of fruit ripening and senescence. This study provides new insights into the molecular mechanisms of strawberry fruit ripening and senescence and high-CO2 treatment applied to postharvest preservation of strawberry fruit from the lncRNA-mRNA perspective.
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