RNA Binding Proteins as Potential Therapeutic Targets in Colorectal Cancer.

RNA-binding proteins (RBPs) play critical roles in regulating post-transcriptional gene expression, managing processes such as mRNA splicing, stability, and translation. In normal intestine, RBPs maintain the tissue homeostasis, but when dysregulated, they can drive colorectal cancer (CRC) development and progression. Understanding the molecular mechanisms behind CRC is vital for developing novel therapeutic strategies, and RBPs are emerging as key players in this area. This review highlights the roles of several RBPs, including LIN28, IGF2BP1-3, Musashi, HuR, and CELF1, in CRC. These RBPs regulate key oncogenes and tumor suppressor genes by influencing mRNA stability and translation. While targeting RBPs poses challenges due to their complex interactions with mRNAs, recent advances in drug discovery have identified small molecule inhibitors that disrupt these interactions. These inhibitors, which target LIN28, IGF2BPs, Musashi, CELF1, and HuR, have shown promising results in preclinical studies. Their ability to modulate RBP activity presents a new therapeutic avenue for treating CRC. In conclusion, RBPs offer significant potential as therapeutic targets in CRC. Although technical challenges remain, ongoing research into the molecular mechanisms of RBPs and the development of selective, potent, and bioavailable inhibitors should lead to more effective treatments and improved outcomes in CRC.

Resveratrol inhibits Lin28A expression and induces its degradation via the proteasomal pathway in NCCIT cells.

Lin28A is an oncoprotein overexpressed in several cancer types such as testicular, ovarian, colon, breast and lung cancers. As a pluripotency factor that promotes tumorigenesis, Lin28A is associated with more undifferentiated and aggressive tumors phenotypes. Moreover, Lin28A is a highly stable protein that is difficult to downregulate. The compound resveratrol (RSV) has anticancer effects. The present study aimed to elucidate the mechanisms underlying the downregulation of Lin28A protein expression by RSV in the NCCIT cell line. NCCIT cells were treated with different concentrations of RSV to investigate its effects on Lin28A expression. The mRNA expression levels of Lin28A and ubiquitin-specific protease 28 (USP28) were assessed using reverse transcription-quantitative PCR. Western blot analysis was employed to evaluate the protein levels of Lin28A, USP28 and phosphorylated Lin28A. In addition, in some experiments, cells were treated with a MAPK/ERK pathway inhibitor, and other experiments involved transfecting cells with small interfering RNAs targeting USP28. The results demonstrated that RSV significantly reduced Lin28A expression by destabilizing the protein; this effect was mediated by the ability of RSV to suppress the expression of USP28, a deubiquitinase that normally protects Lin28A from ubiquitination and degradation. Additionally, RSV inhibited phosphorylation of Lin28A via the MAPK/ERK pathway; this phosphorylation event has previously been shown to enhance the stability of Lin28A by increasing its half-life. This resulted in Lin28A degradation through the proteasomal pathway in NCCIT cells. The results provide further evidence of the anticancer activity of RSV, and identified Lin28A and USP28 as promising therapeutic targets. As a stable oncoprotein, downregulating Lin28A expression is challenging. However, the present study demonstrated that RSV can overcome this hurdle by inhibiting USP28 expression and MAPK/ERK signaling to promote Lin28A degradation. Furthermore, elucidating these mechanisms provides avenues for developing targeted cancer therapies.

LIN28-Targeting Chromenopyrazoles and Tetrahydroquinolines Induced Cellular Morphological Changes and Showed High Biosimilarity with BRD PROTACs.

The probing of small molecules with heterocyclic scaffolds covering unexplored chemical space and the evaluation of their biological relevance are essential parts of forward chemical genetics approaches and for the development of potential small-molecule therapeutics. In this study, we profiled sets of chromenopyrazoles (CMPs) and tetrahydroquinolines (THQs), originally developed to target the protein-RNA interaction of LIN28-let-7, in a cell painting assay (CPA) measuring cellular morphological changes. Selected LIN28-inactive CMPs and THQs induced cellular morphological changes to different extents. The most CPA-active CMPs 2 and 3 exhibited high bio-similarity with the LCH and BET clusters, while the most CPA-active THQs 13 and 20 indicated a mechanism of action beyond the currently established biosimilarity clusters. Overall, this work demonstrated that CPA is useful in revealing "hidden" biological targets and mechanisms of action for biologically inactive small molecules, which are CMPs and THQs targeting the RNA-binding protein LIN28 in this case, evaluated in target-based strategies. When compared with annotated reference compounds, CMP 3 exhibited a high biosimilarity with the dual BRD7/9 degrading PROTAC VZ185, suggesting that CPA could potentially function as a new phenotypic approach to identify degrader molecules.

The Prognostic Value of Combined LIN28B and IGF-1R in Colorectal Cancer.

OBJECTIVE: LIN28B and insulin-like growth factor-1 receptor (IGF-1R) play important roles in the growth and metastasis of colorectal cancer (CRC). The relationship between LIN28B and IGF-1R and their co-expression role in CRC is unknown. This study aims to assess whether the combined detection of LIN28B and IGF-1R is a better predictor of prognosis in CRC than either marker alone. METHODS: We used immunohistochemistry to detect LIN28B and IGF-1R protein. The correlation between LIN28B and IGF-1R expression in CRC was determined by the Spearman correlation analysis. The association between LIN28B/IGF-1R expression and clinicopathological features was analyzed, and overall survivals were also performed. RESULTS: The expression of LIN28B and IGF-1R in CRC tissues were significantly higher than that in non-cancerous tissues (P<0.001 and P<0.001, respectively). LIN28B over-expression positively correlated with IGF-1R over-expression (r=0.283, P=0.007). The increased expression of LIN28B and IGF-1R were both significantly correlated with TNM stage, lymph node metastasis and distant metastasis (all P<0.05). IGF-1R, not LIN28B, was significantly associated with vascular invasion (P=0.007). Overall survival appears to be lower in patients with high LIN28B expression or/and high IGF-1R expression than those with low LIN28B expression or/and low IGF-1R expression. In addition, the predictive sensitivity of LIN28B combined with IGF-1R was stronger than that of either one alone. CONCLUSIONS: The combined over-expression of LIN28B and IGF-1R in patients with colorectal cancer may provide a more powerful predictor for CRC prognosis.

Genetic determinants of age at menarche: does the LIN28B gene play a role? A narrative review.

Menarche, the first menstrual period marking the onset of female reproduction, is a milestone of female puberty. The timing of menarche determines the timing of later phases of pubertal maturation in girls and has major implications for health later in life, including behavioral and psychosocial disorders during adolescence and fertility problems and increased risk for certain diseases in adulthood. Over the last few decades, a continuous decline in age at menarche has been noted, with environmental factors contributing to this change in the timing of menarche. However, a genetic component of age at menarche and pubertal onset has been strongly suggested by studies in families and twins wherein up to approximately 80% of the variance in puberty onset can be explained by heritability. Gene association studies have revealed several genetic loci involved in age at menarche, among which LIN28B has emerged as a key regulator of female growth and puberty. LIN28B, a human homolog of Lin28 of C. elegans, is a known RNA-binding protein that regulates let-7 microRNA biogenesis. Genome-wide association studies have identified the association of polymorphisms in the LIN28B gene with age at menarche in several population cohorts worldwide. In this paper, we review the genetic factors contributing to age of menarche, with particular focus on the identified polymorphisms in LIN28B gene.

Association of LIN28B Gene Polymorphisms with Intrauterine Adhesions in Patients after Curettage Abortion.

Background/Objectives: Intrauterine adhesion (IUA) is characterized by endometrial fibrocyte hyperplasia. The LIN28B gene is associated with many proliferative diseases. However, its association with IUA is entirely unknown. We hypothesized that LIN28B gene polymorphisms are responsible for IUA susceptibility after curettage abortion. Methods: In this genetic association study, We genotyped two common polymorphisms (rs369065 C>T and rs314280 A>G) in 107 patients with IUA and 270 controls without IUA after curettage abortion from a Chinese population between July 2022 and May 2023 and analyzed their associations with IUA risk using multiple logistic regression models. Results: The carriers of genotype rs314280 AA of the LIN28B gene showed an increased risk of IUA (AOR [adjusted odds ratio] = 2.12, 95% CI [confidence interval] = 1.151-3.903), compared to GG+GA genotypes. Further stratification analyses showed that the deleterious role of the rs314280 AA genotype was more evident in patients with fewer than four pregnancies (AOR = 2.740, 95% CI = 1.355-5.540), fewer than two births (AOR = 2.676, 95% CI = 1.300-5.509), and fibrous (AOR = 2.082, 95% CI = 1.084-3.997) and muscular adhesions (AOR = 3.887, 95% CI = 1.116-13.540). However, the rs369065 T>C polymorphism of the LIN28B gene was not significantly associated with the occurrence of IUA. Conclusions: The rs314280 AA genotype of the LIN28B gene is associated with an increased risk of IUA in patients after curettage abortion, especially in those with fewer pregnancies or parities and higher disease severity. Our findings implicate a precise choice of clinical counseling and decision-making of IUA, thereby protecting female reproduction.

Single-cell profiling identifies LIN28A mRNA targets in the mouse pluripotent-to-2C-like transition and somatic cell reprogramming.

RNA-binding proteins (RBPs) regulate totipotency, pluripotency maintenance, and induction. The intricacies of how they modulate these processes through their interaction with RNAs remain to be elucidated. Here we employed Targets of RBPs Identified By Editing (TRIBE) with single-cell resolution (scTRIBE) to profile the mRNA targets of the key pluripotency regulator LIN28A in mouse embryonic stem cells (ESCs), 2-cell embryo-like cells (2CLCs) and somatic cell reprogramming. LIN28A is known to act by controlling the maturation of the let-7 microRNA but, in addition, it binds to multiple mRNAs and influences their stability and translation efficiency. However, the mRNA targets of LIN28A in 2CLCs and reprogramming are unclear. Through quantitative single-cell analysis of the scTRIBE dataset, we observed a marked increase in the binding of LIN28A to mRNAs of ribosome biogenesis factors and a selected group of totipotency factors in 2CLCs within ESC cultures. Our results suggest that LIN28A extends the half-life of at least some of these mRNAs, providing new insights into its role in the totipotent state. We also uncovered the distinct trajectory-specific LIN28A-mRNA networks in reprogramming, helping explain how LIN28A facilitates the mesenchymal-to-epithelial transition and pluripotency acquisition. Our study not only clarifies the multifunctional role of LIN28A in these processes but also highlights the importance of decoding RNA-protein interactions at the single-cell level.

Study of rs7759938, rs314280, and rs314276 Polymorphisms of LIN28B in Relation to Age at Menarche in Girls of Greek Descent.

BACKGROUND: Single-nucleotide polymorphisms in LIN28B, critical regulators of female growth and puberty, have been linked to age at menarche. METHODS: We assessed the association of rs7759938, rs314280, and rs314276 with menarcheal age in girls of Greek descent. We reviewed the records of 248 girls who had their first menstruation before 18 years and who attended the Greek Departments of Pediatric Endocrinology from January 2021 to July 2023. Genotyping was performed by standard DNA-based methods. Association analyses involved both parametric and non-parametric tests. RESULTS: The average age of breast and pubic hair development was 9.95 years, and the age at menarche was 11.55 years. Menarche occurred ≤11 years (mean 10.24 years) in 108 girls (43.5%) and >11 years (mean 12.55 years) in 140 (56.5%). The girls' menarcheal age correlated significantly with that of their mothers (average 12.1 years, p-value < 0.0001, Spearman's r 0.350). The dominant rs7759938(TT) genotype was the most common (55.2%), followed by the dominant rs314276(CC) (53.2%) and dominant rs314280(TT) (14.5%) genotypes. CONCLUSIONS: There was no association between age at menarche and any of the polymorphism genotypes/alleles or between genotypes/alleles and birth weight, gestational week, mode of delivery, and maternal age at menarche. Future large sample studies are warranted to confirm these results.

The role of Lin28A and Lin28B in cancer beyond Let-7.

Lin28A and Lin28B are paralogous RNA-binding proteins that play fundamental roles in development and cancer by regulating the microRNA family of tumor suppressor Let-7. Although Lin28A and Lin28B share some functional similarities with Let-7 inhibitors, they also have distinct expression patterns and biological functions. Increasing evidence indicates that Lin28A and Lin28B differentially impact cancer stem cell properties, epithelial-mesenchymal transition, metabolic reprogramming, and other hallmarks of cancer. Therefore, it is important to understand the overexpression of Lin28A and Lin28B paralogs in specific cancer contexts. In this review, we summarize the main similarities and differences between Lin28A and Lin28B, their implications in different cellular processes, and their role in different types of cancer. In addition, we provide evidence of other specific targets of each lin28 paralog, as well as the lncRNAs and miRNAs that promote or inhibit its expression, and how this impacts cancer development and progression.

Clinical significance of LIN28A gene polymorphisms and expression in pan-cancer: a meta-analysis and bioinformatic analysis.

Several studies have reported the relationship between LIN28A gene polymorphisms (rs3811463 T > C and rs34787247 G > A) and cancer susceptibility, but the results are inconsistent and need further clarification. The current study aimed to evaluate their relationship and also to explore the relationship between LIN28A gene expression and immune infiltration, tumor stage, survival prognosis, and drug sensitivity in pan-cancer. The meta-analysis and data mining were completed by STATA software and the GSCA platform, respectively. The meta-analysis showed that the rs3811463 polymorphism was not associated with cancer susceptibility, while the rs34787247 polymorphism was associated with cancer susceptibility in the Chinese population [AA vs. GG: Odd Ratio (OR)=1.98, 95% Confidence Interval (CI)=1.35-2.89, PZ<0.001; GA vs. GG: OR = 1.17, 95%CI= 1.01-1.36, PZ=0.04; (AA + GA) vs. GG: OR = 1.24, 95%CI = 1.07-1.43, PZ=0.004; AA vs. (GA + GG): OR = 1.90, 95%CI = 1.30- 2.78, PZ=0.001; A vs. G: OR = 1.27, 95%CI = 1.12-1.44, PZ<0.001]. LIN28A gene expression was associated not only with immune infiltration, pathological stage, and survival prognosis of certain cancers, but also with sensitivity to multiple anticancer drugs, such as cisplatin, pazopanib, olaparib, and selumetinib. In conclusion, the current study suggested that the rs34787247 G > A polymorphism might be used as a cancer risk marker in the Chinese population, and LIN28A might serve as a prognostic marker and therapeutic target for certain cancers.

Optimized rAAV8 targeting acinar KLF4 ameliorates fibrosis in chronic pancreatitis via exosomes-enriched let-7s suppressing pancreatic stellate cells activation.

Chronic pancreatitis (CP) is marked by progressive fibrosis and the activation of pancreatic stellate cells (PSCs), accompanied by the destruction of pancreatic parenchyma, leading to the loss of acinar cells (ACs). Few research studies have explored the mechanism by which damaged ACs (DACs) contribute to PSCs activation and pancreatic fibrosis. Currently, there are no effective drugs for curing CP or limiting the progression of pancreatic fibrosis. In this research, co-culture with intact acinar cells (IACs) suppressed PSC activation, while co-culture with DACs did the opposite. Krüppel-like factor 4 (KLF4) was significantly upregulated in DACs and was established as the key molecule that switches ACs from PSCs-suppressor to PSCs-activator. We revealed the exosomes of IACs contributed to the anti-activated function of IACs-CS on PSCs. MiRNome profiling showed that let-7 family is significantly enriched in IAC-derived exosomes (>30% miRNome), which partially mediates IACs' suppressive impacts on PSCs. Furthermore, it has been observed that the enrichment of let-7 in exosomes was influenced by the expression level of KLF4. Mechanistic studies demonstrated that KLF4 in ACs upregulated Lin28A, thereby decreasing let-7 levels in AC-derived exosomes, and thus promoting PSCs activation. We utilized an adeno-associated virus specifically targeting KLF4 in ACs (shKLF4-pAAV) to suppress PSCs activation in CP, resulting in reduced pancreatic fibrosis. IAC-derived exosomes hold potential as potent weapons against PSCs activation via let-7s, while activated KLF4/Lin28A signaling in DACs diminished such functions. ShKLF4-pAAV holds promise as a novel therapeutic approach for CP.

N6-methyladenosine modification of circMARK2 enhances cytoplasmic export and stabilizes LIN28B, contributing to the progression of Wilms tumor.

BACKGROUND: The potential involvement of circular RNAs (circRNAs) and N6-methyladenosine (m6A) modification in the progression of Wilms tumor (WT) has not been fully elucidated. This study investigates the regulatory mechanisms and clinical significance of m6A-modified circMARK2 and its role in WT progression. METHODS: We identified dysregulated circRNAs through deep sequencing and validated their expression by qRT-PCR in WT tissues. The biological functions of circMARK2 were assessed using clone formation, transwell migration, and orthotopic animal models. To dissect the underlying mechanisms, we employed RNA immunoprecipitation, RNA pull-down, dual-luciferase reporter assays, Western blotting, and immunofluorescence and immunohistochemical staining. RESULTS: CircMARK2, upregulated in WT tissues, was found to be m6A-modified and promoted cytoplasmic export. It facilitated WT progression by stabilizing LIN28B mRNA through the circMARK2/IGF2BP2 interaction. In vitro and in vivo studies demonstrated that circMARK2 enhances the malignant behavior of WT cells. Clinically, higher circMARK2 levels in tumor tissues of WT patients were linked to increased tumor aggressiveness and reduced survival rates. CONCLUSIONS: Our study provides the first comprehensive evidence that m6A-modified circMARK2 contributes to WT progression by enhancing LIN28B mRNA stability, promoting cellular aggressiveness. CircMARK2 emerges as a potential biomarker for prognosis and a promising target for therapeutic intervention in WT, underscoring the clinical relevance of m6A modification in pediatric renal cancer.

Progress on the role of LIN28A/B in tumor development and progression.

LIN28A and its homolog LIN28B are highly conserved RNA-binding proteins that play important roles in early embryonic development, somatic cell reprogramming, metabolism and tumorigenesis. LIN28A/B are highly expressed in a variety of malignant tumors such as breast cancer. They play important roles in the initiation, maintenance, and metastasis of tumors and are associated with poor prognosis. Previous studies have shown that the main regulatory mechanisms of LIN28A/B include let-7s dependent ways and let-7s independent ways, such as directly targeting mRNA. In this review, we summarize the function and molecular regulatory mechanisms of LIN28A/B in malignant tumors such as liver cancer, breast cancer and colorectal cancer, in order to provide references for further exploring the function and mechanism of LIN28A/B and their possible roles in clinical applications.

Expression of Pluripotency Factors OCT4 and LIN28 Correlates with Survival Outcome in Lung Adenocarcinoma.

Background and Objectives: Lung adenocarcinoma is a leading cause of cancer-related mortality despite recent therapeutic advances. Cancer stem cells have gained increasing attention due to their ability to induce cancer cell proliferation through self-renewal and differentiation into multiple cell lineages. OCT4 and LIN28 (and their homologs A and B) have been identified as key regulators of pluripotency in mammalian embryonic (ES) and induced stem (IS) cells, and they are the crucial regulators of cancer progression. However, their exact role in lung adenocarcinoma has not yet been clarified. Materials and Methods: The aim of this study was to explore the role of the pluripotency factors OCT4 and LIN28 in a cohort of surgically resected human lung adenocarcinomas to reveal possible biomarkers for lung adenocarcinoma prognosis and potential therapeutic targets. The expressions of OCT4, LIN28A and LIN28B were analyzed in formalin-fixed, paraffin-embedded tissue samples from 96 patients with lung adenocarcinoma by immunohistochemistry. The results were analyzed with clinicopathologic parameters and were related to the prognosis of patients. Results: Higher OCT4 expression was related to an improved 5-year overall survival (OS) rate (p < 0.001). Nuclear LIN28B expression was lower in stage I and II tumors (p < 0.05) compared to advanced stage tumors. LIN28B cytoplasmic expression was associated with 5-year OS rates not only in univariate (p < 0.005), but also in multivariate analysis (where age, gender, histopathological subtype and stage were used as cofactors, p < 0.01 HR = 2.592). Patients with lower LIN28B expression showed improved 5-year OS rates compared to patients with increased LIN28B expression. Conclusions: Our findings indicate that OCT4 and LIN28B are implicated in lung adenocarcinoma progression and prognosis outcome; thus, they serve as promising prognostic biomarkers and putative therapeutic targets in lung adenocarcinomas.

A temporal sequence of heterochronic gene activities promotes stage-specific developmental events in Caenorhabditis elegans.

The heterochronic genes of the nematode Caenorhabditis elegans control the succession of postembryonic developmental events. The 4 core heterochronic genes lin-14, lin-28, hbl-1, and lin-41 act in a sequence to specify cell fates specific to each of the 4 larval stages. It was previously shown that lin-14 has 2 activities separated in time that promote L1 and L2 developmental events, respectively. Using the auxin-inducible degron system, we find that lin-28 and hbl-1 each have 2 activities that control L2 and L3 events which are also separated in time. Relative to events they control, both lin-28 and hbl-1 appear to act just prior to or concurrently with events of the L2. Relative to each other, lin-28 and hbl-1 appear to act simultaneously. By contrast, the lin-14 activity controlling L2 events precedes those of lin-28 and hbl-1 controlling the same events, suggesting that lin-14's regulation of lin-28 is responsible for the delay. Likewise, the activities of lin-28 and hbl-1 controlling L3 fates act well in advance of those fates, suggesting a similar regulatory gap. lin-41 acts early in the L3 to affect fates of the L4, although it was not possible to determine whether it too has 2 temporally separated activities. We also uncovered a feedback phenomenon that prevents the reactivation of heterochronic gene activity late in development after it has been downregulated. This study places the heterochronic gene activities into a timeline of postembryonic development relative to one another and to the developmental events whose timing they control.

EGCG Disrupts the LIN28B/Let-7 Interaction and Reduces Neuroblastoma Aggressiveness.

Neuroblastoma (NB) is the most commonly diagnosed extracranial solid tumor in children, accounting for 15% of all childhood cancer deaths. Although the 5-year survival rate of patients with a high-risk disease has increased in recent decades, NB remains a challenge in pediatric oncology, and the identification of novel potential therapeutic targets and agents is an urgent clinical need. The RNA-binding protein LIN28B has been identified as an oncogene in NB and is associated with a poor prognosis. Given that LIN28B acts by negatively regulating the biogenesis of the tumor suppressor let-7 miRNAs, we reasoned that selective interference with the LIN28B/let-7 miRNA interaction would increase let-7 miRNA levels, ultimately leading to reduced NB aggressiveness. Here, we selected (-)-epigallocatechin 3-gallate (EGCG) out of 4959 molecules screened as the molecule with the best inhibitory activity on LIN28B/let-7 miRNA interaction and showed that treatment with PLC/PLGA-PEG nanoparticles containing EGCG (EGCG-NPs) led to an increase in mature let-7 miRNAs and a consequent inhibition of NB cell growth. In addition, EGCG-NP pretreatment reduced the tumorigenic potential of NB cells in vivo. These experiments suggest that the LIN28B/let-7 miRNA axis is a good therapeutic target in NB and that EGCG, which can interfere with this interaction, deserves further preclinical evaluation.

Proto-oncogene c-Myb potentiates cisplatin resistance of ovarian cancer cells by downregulating lncRNA NKILA and modulating cancer stemness and LIN28A-let7 axis.

Ovarian cancer is a major gynecological cancer that has poor prognosis associated mainly to its late diagnosis. Cisplatin is an FDA approved ovarian cancer therapy and even though the therapy is initially promising, the patients mostly progress to resistance against cisplatin. The underlying mechanisms are complex and not very clearly understood. Using two different paired cell lines representing cisplatin-sensitive and the cisplatin-resistant ovarian cancer cells, the ES2 and the A2780 parental and cisplatin-resistant cells, we show an elevated proto-oncogene c-Myb in resistant cells. We further show down-regulated lncRNA NKILA in resistant cells with its de-repression in resistant cells when c-Myb is silenced. NKILA negatively correlates with cancer cell and invasion but has no effect on cellular proliferation or cell cycle. C-Myb activates NF-κB signaling which is inhibited by NKILA. The cisplatin resistant cells are also marked by upregulated stem cell markers, particularly LIN28A and OCT4, and downregulated LIN28A-targeted let-7 family miRNAs. Whereas LIN28A and downregulated let-7s individually de-repress c-Myb-mediated cisplatin resistance, the ectopic expression of let-7s attenuates LIN28A effects, thus underlying a c-Myb-NKILA-LIN28A-let-7 axis in cisplatin resistance of ovarian cancer cells that needs to be further explored for therapeutic intervention.

Inhibition of Let-7b-5p maturation by LIN28A promotes thermal skin damage repair after burn injury.

Burn injuries, especially severe ones, result in direct and indirect thermal damage to skin tissues, with a complex and slow wound healing process. Improper treatment can induce sustained inflammatory responses, causing systemic damage. Lin28A, a highly conserved RNA binding protein, was found to exert a significant effect on cell proliferation and wound repair. Lin28A exerts the functions through inhibiting the maturation of the let-7 family miRNAs. Herein, the roles of Lin28A and let-7b in thermal injury repair were investigated using a mouse thermal injury model and a human skin fibroblast (HSF) model for thermal injuries. Lin28A could inhibit the maturation of let-7b, thus participating in skin repair after burns. In the animal model, Lin28A was highly expressed after thermal injury. In the HSF model for thermal injuries, downregulation of Lin28A inhibited the proliferation, migration, and extracellular matrix (ECM) generation of fibroblasts. When let-7b was knocked down in HSFs, the impacts on fibroblast functions caused by downregulation of Lin28A were partially reversed. Moreover, let-7b overexpression might significantly attenuate the promotive effects of Lin28A upon thermal injury repair. Finally, AKT2 and IGF1R were the let-7b target genes within cells. These findings reveal that Lin28A might promote thermal injury repair in burn-injured skin by inhibiting the maturation of let-7b and improving HSF viability and functions, thus illustrating the critical effect of let-7b on burn wound healing and providing new therapeutic targets and strategies for burn treatment.

Identification of small molecule inhibitors against Lin28/let-7 to suppress tumor progression and its alleviation role in LIN28-dependent glucose metabolism.

The reciprocal suppression of an RNA-binding protein LIN28 (human abnormal cell lineage 28) and miRNA Let-7 (Lethal 7) is considered to have a prime role in hepatocellular carcinoma (HCC). Though targeting this inhibition interaction is effective for therapeutics, it causes other unfavorable effects on glucose metabolism and increased insulin resistance. Hence, this study aims to identify small molecules targeting Lin28/let-7 interaction along with additional potency to improve insulin sensitivity. Of 22,14,996 small molecules screened by high throughput virtual screening, 6 molecules, namely 41354, 1558, 12437, 23837, 15710, and 8319 were able to block the LIN28 interaction with let-7 and increase the insulin sensitivity via interacting with PPARγ (peroxisome proliferator-activated receptors γ). MM-GBSA (Molecular Mechanics-Generalized Born Surface Area) analysis is used to re-score the binding affinity of docked complexes. Upon further analysis, it is also seen that these molecules have superior ADME (Absorption, Distribution, Metabolism, and Excretion) properties and form stable complexes with the targets for a significant period in a biologically simulated environment (Molecular Dynamics simulation) for 100 ns. From our results, we hypothesize that these identified 6 small molecules can be potential candidates for HCC treatment and the glucose metabolic disorder caused by the HCC treatment.

GNAI3 mediated by Lin28A regulates lipopolysaccharide-induced inflammation and osteogenic differentiation in periodontal stem cells by mediating the NF-κB/NLRP3 inflammasome pathway.

OBJECTIVES: The aim of this study was to investigate the regulatory role of G protein subunit alpha i3 (GNAI3) in periodontitis. DESIGN: Following the induction of human periodontal ligament stem cells (hPDLSCs) with lipopolysaccharide (LPS), the mRNA and protein expressions of GNAI3 and Lin28A were detected by real-time quantitative polymerase chain reaction (RT-qPCR) and western blot. The transfection efficiency of Oe-GNAI3 and sh-Lin28A was examined by virtue of RT-qPCR and western blot. With the application of ELISA and flow cytometry, the releases of inflammatory cytokines and cell apoptosis were appraised. Alkaline phosphatase (ALP) staining and alizarin red S (ARS) staining were conducted to evaluate osteogenic differentiation. Next, the binding ability of Lin28A with GNAI3 mRNA was estimated by radioimmunoprecipitation (RIP) assay while the stability of GNAI3 mRNA was assessed utilizing RT-qPCR. Western blot was employed for the measurement of inflammation-, apoptosis- and nuclear factor-kappaB (NF-κB)/NOD-like receptor family pyrin domain containing 3 (NLRP3) inflammasome pathway-related proteins and osteogenic markers. RESULTS: The expression of GNAI3 was down-regulated in LPS-induced hPDLSCs. After the transfection with Oe-GNAI3, the inflammation and apoptosis in LPS-induced hPDLSCs were inhibited while osteogenic differentiation was promoted. Moreover, Lin28A could stabilize GNAI3 mRNA and Lin28A knockdown significantly reduced GNAI3 expression. Further experiments verified that the inhibitory effects of GNAI3 overexpression on LPS-induced cellular inflammation and cell apoptosis as well as the promotive effects on osteogenic differentiation in hPDLSCs were all partially counteracted by Lin28A depletion, which may possibly be mediated via the regulation of the NF-κB/NLRP3 inflammasome pathway. CONCLUSION: GNAI3 that mediated by Lin28A regulates the inflammation and osteogenic differentiation in LPS-induced hPDLSCs by mediating the NF-κB/NLRP3 inflammasome pathway.