c-Myc target genes involved in cell growth, apoptosis, and metabolism

Integrated bioinformatics analysis identifies autophagy-associated genes as candidate biomarkers and reveals the immune infiltration landscape in psoriasis

Autophagy is implicated in the pathogenesis of psoriasis. We aimed to identify autophagy-related biomarkers in psoriasis via an integrated bioinformatics approach. We downloaded the gene expression profiles of GSE30999 dataset, and the "limma" package was applied to identify differentially expressed genes (DEGs). Then, differentially expressed autophagy-related genes (DEARGs) were identified via integrating autophagy-related genes with DEGs. CytoHubba plugin was used for the identification of hub genes and verified by the GSE41662 dataset. Subsequently, a series of bioinformatics analyses were employed, including protein-protein interaction network, functional enrichment, spearman correlation, receiver operating characteristic, and immune infiltration analyses. One hundred and one DEARGs were identified, and seven DEARGs were identified as hub genes and verified using the GSE41662 dataset. These validated genes had good diagnostic value in distinguishing psoriasis lesions. Immune infiltration analysis indicated that ATG5, SQSTM1, EGFR, MAPK8, MAPK3, MYC, and PIK3C3 were correlated with infiltration of immune cells. Seven DEARGs, namely ATG5, SQSTM1, EGFR, MAPK8, MAPK3, MYC, and PIK3C3, may be involved in the pathogenesis of psoriasis, which expanded the understanding of the development of psoriasis and provided important clinical significance for treatment of this disease.

Better maintenance of enzymatic capacity and higher levels of substrate transporter proteins in skeletal muscle of aging female mice

This study investigated sex-specific differences in high-energy phosphate, glycolytic, and mitochondrial enzyme activities and also metabolite transporter protein levels in the skeletal muscles of adult (5 months old), middle-aged (12 months old), and advanced-aged (24 months old) mice. While gastrocnemius glycogen content increased with age regardless of sex, gastrocnemius triglyceride levels increased only in advanced-aged female mice. Aging decreased creatine kinase and adenylate kinase activities in the plantaris muscle of both sexes and in the soleus muscle of male mice but not in female mice. Irrespective of sex, phosphofructokinase and lactate dehydrogenase (LDH) activities decreased in the plantaris and soleus muscles. Additionally, hexokinase activity in the plantaris muscle and LDH activity in the soleus muscle decreased to a greater extent in aged male mice compared with those in aged female mice. Mitochondrial enzyme activities increased in the plantaris muscle of aged female mice but did not change in male mice. The protein content of the glucose transporter 4 in the aged plantaris muscle and fatty acid translocase/cluster of differentiation 36 increased in the aged plantaris and soleus muscles of both sexes, with a significantly higher content in female mice. These findings suggest that females possess a better ability to maintain metabolic enzyme activity and higher levels of metabolite transport proteins in skeletal muscle during aging, despite alterations in lipid metabolism. Our data provide a basis for studying muscle metabolism in the context of age-dependent metabolic perturbations and diseases that affect females and males differently.

Circular RNA hsa_circ_0000467 promotes colorectal cancer progression by promoting eIF4A3-mediated c-Myc translation

BACKGROUND

Colorectal cancer (CRC) is the second most common malignant tumor worldwide, and its incidence rate increases annually. Early diagnosis and treatment are crucial for improving the prognosis of patients with colorectal cancer. Circular RNAs are noncoding RNAs with a closed-loop structure that play a significant role in tumor development. However, the role of circular RNAs in CRC is poorly understood.

METHODS

The circular RNA hsa_circ_0000467 was screened in CRC circRNA microarrays using a bioinformatics analysis, and the expression of hsa_circ_0000467 in CRC tissues was determined by in situ hybridization. The associations between the expression level of hsa_circ_0000467 and the clinical characteristics of CRC patients were evaluated. Then, the role of hsa_circ_0000467 in CRC growth and metastasis was assessed by CCK8 assay, EdU assay, plate colony formation assay, wound healing assay, and Transwell assay in vitro and in a mouse model of CRC in vivo. Proteomic analysis and western blotting were performed to investigate the effect of hsa_circ_0000467 on c-Myc signaling. Polysome profiling, RT‒qPCR and dual-luciferase reporter assays were performed to determine the effect of hsa_circ_0000467 on c-Myc translation. RNA pull-down, RNA immunoprecipitation (RIP) and immunofluorescence staining were performed to assess the effect of hsa_circ_0000467 on eIF4A3 distribution.

RESULTS

In this study, we found that the circular RNA hsa_circ_0000467 is highly expressed in colorectal cancer and is significantly correlated with poor prognosis in CRC patients. In vitro and in vivo experiments revealed that hsa_circ_0000467 promotes the growth and metastasis of colorectal cancer cells. Mechanistically, hsa_circ_0000467 binds eIF4A3 to suppress its nuclear translocation. In addition, it can also act as a scaffold molecule that binds eIF4A3 and c-Myc mRNA to form complexes in the cytoplasm, thereby promoting the translation of c-Myc. In turn, c-Myc upregulates its downstream targets, including the cell cycle-related factors cyclin D2 and CDK4 and the tight junction-related factor ZEB1, and downregulates E-cadherin, which ultimately promotes the growth and metastasis of CRC.

CONCLUSIONS

Our findings revealed that hsa_circRNA_0000467 plays a role in the progression of CRC by promoting eIF4A3-mediated c-Myc translation. This study provides a theoretical basis and molecular target for the diagnosis and treatment of CRC.

Exploring Myc puzzle: Insights into cancer, stem cell biology, and PPI networks

"The grand orchestrator," "Universal Amplifier," "double-edged sword," and "Undruggable" are just some of the Myc oncogene so-called names. It has been around 40 years since the discovery of the Myc, and it remains in the mainstream of cancer treatment drugs. Myc is part of basic helix-loop-helix leucine zipper (bHLH-LZ) superfamily proteins, and its dysregulation can be seen in many malignant human tumors. It dysregulates critical pathways in cells that are connected to each other, such as proliferation, growth, cell cycle, and cell adhesion, impacts miRNAs action, intercellular metabolism, DNA replication, differentiation, microenvironment regulation, angiogenesis, and metastasis. Myc, surprisingly, is used in stem cell research too. Its family includes three members, MYC, MYCN, and MYCL, and each dysfunction was observed in different cancer types. This review aims to introduce Myc and its function in the body. Besides, Myc deregulatory mechanisms in cancer cells, their intricate aspects will be discussed. We will look at promising drugs and Myc-based therapies. Finally, Myc and its role in stemness, Myc pathways based on PPI network analysis, and future insights will be explained.

TRIP13 Plays an Important Role in the Sensitivity of Leukemia Cell Response to Sulforaphane Therapy

Sulforaphane is one of the most characterized isothiocyanate compounds in cruciferous vegetables and shows anticancer effects, especially antileukemia properties. However, the molecular mechanism of the growth inhibition effect of sulforaphane in acute myeloid leukemia (AML) has not been fully explored. In the present study, a proteomic analysis was performed on the AML cell line U937 responding to sulforaphane treatment to identify novel and efficient therapeutic targets of sulforaphane on AML cells. Key driver analysis was run on the leukemia network, and TRIP13 was identified as a key regulatory factor in sulforaphane-induced growth inhibition in U937 cells. Pretreatment with DCZ0415, an inhibitor of TRIP13, could significantly attenuate sulforaphane-induced cell apoptosis and cell cycle arrest in vitro through the PI3K/Akt/mTOR signaling pathway. In addition, the inhibitory effect of sulforaphane on the tumor volume could also be obviously attenuated by the pretreatment of DCZ0415 in vivo. These results indicate that TRIP13 plays an important role in the sensitivity of leukemia cell response to sulforaphane treatment, and these findings expand the understanding of the mechanism of the antileukemic effect of sulforaphane and provide a new target for the treatment of AML.

Michael Acceptors as Anti-Cancer Compounds: Coincidence or Causality?

Michael acceptors represent a class of compounds with potential anti-cancer properties. They act by binding to nucleophilic sites in biological molecules, thereby disrupting cancer cell function and inducing cell death. This mode of action, as well as their ability to be modified and targeted, makes them a promising avenue for advancing cancer therapy. We are investigating the molecular mechanisms underlying Michael acceptors and their interactions with cancer cells, in particular their ability to interfere with cellular processes and induce apoptosis. The anti-cancer properties of Michael acceptors are not accidental but are due to their chemical structure and reactivity. The electrophilic nature of these compounds allows them to selectively target nucleophilic residues on disease-associated proteins, resulting in significant therapeutic benefits and minimal toxicity in various diseases. This opens up new perspectives for the development of more effective and precise cancer drugs. Nevertheless, further studies are essential to fully understand the impact of our discoveries and translate them into clinical practice.

RGS19 activates the MYH9/β-catenin/c-Myc positive feedback loop in hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is one of the most common fatal cancers worldwide, and the identification of novel treatment targets and prognostic biomarkers is urgently needed because of its unsatisfactory prognosis. Regulator of G-protein signaling 19 (RGS19) is a multifunctional protein that regulates the progression of various cancers. However, the specific function of RGS19 in HCC remains unclear. The expression of RGS19 was determined in clinical HCC samples. Functional and molecular biology experiments involving RGS19 were performed to explore the potential mechanisms of RGS19 in HCC. The results showed that the expression of RGS19 is upregulated in HCC tissues and is significantly associated with poor prognosis in HCC patients. RGS19 promotes the proliferation and metastasis of HCC cells in vitro and in vivo. Mechanistically, RGS19, via its RGS domain, stabilizes the MYH9 protein by directly inhibiting the interaction of MYH9 with STUB1, which has been identified as an E3 ligase of MYH9. Moreover, RGS19 activates β-catenin/c-Myc signaling via MYH9, and RGS19 is also a transcriptional target gene of c-Myc. A positive feedback loop formed by RGS19, MYH9, and the β-catenin/c-Myc axis was found in HCC. In conclusion, our research revealed that competition between RGS19 and STUB1 is a critical mechanism of MYH9 regulation and that the RGS19/MYH9/β-catenin/c-Myc feedback loop may represent a promising strategy for HCC therapy.

The OGT-c-Myc-PDK2 axis rewires the TCA cycle and promotes colorectal tumor growth

Deregulated glucose metabolism termed the "Warburg effect" is a fundamental feature of cancers, including the colorectal cancer. This is typically characterized with an increased rate of glycolysis, and a concomitant reduced rate of the tricarboxylic acid (TCA) cycle metabolism as compared to the normal cells. How the TCA cycle is manipulated in cancer cells remains unknown. Here, we show that O-linked N-acetylglucosamine (O-GlcNAc) regulates the TCA cycle in colorectal cancer cells. Depletion of OGT, the sole transferase of O-GlcNAc, significantly increases the TCA cycle metabolism in colorectal cancer cells. Mechanistically, OGT-catalyzed O-GlcNAc modification of c-Myc at serine 415 (S415) increases c-Myc stability, which transcriptionally upregulates the expression of pyruvate dehydrogenase kinase 2 (PDK2). PDK2 phosphorylates pyruvate dehydrogenase (PDH) to inhibit the activity of mitochondrial pyruvate dehydrogenase complex, which reduces mitochondrial pyruvate metabolism, suppresses reactive oxygen species production, and promotes xenograft tumor growth. Furthermore, c-Myc S415 glycosylation levels positively correlate with PDK2 expression levels in clinical colorectal tumor tissues. This study highlights the OGT-c-Myc-PDK2 axis as a key mechanism linking oncoprotein activation with deregulated glucose metabolism in colorectal cancer.

Intestinal remodeling during Xenopus metamorphosis as a model for studying thyroid hormone signaling and adult organogenesis

Intestinal development takes places in two phases, the initial formation of neonatal (mammals)/larval (anurans) intestine and its subsequent maturation into the adult form. This maturation occurs during postembryonic development when plasma thyroid hormone (T3) level peaks. In anurans such as the highly related Xenopus laevis and Xenopus tropicalis, the larval/tadpole intestine is drastically remodeled from a simple tubular structure to a complex, multi-folded adult organ during T3-dependent metamorphosis. This involved complete degeneration of larval epithelium via programmed cell death and de novo formation of adult epithelium, with concurrent maturation of the muscles and connective tissue. Here, we will summarize our current understanding of the underlying molecular mechanisms, with a focus on more recent genetic and genome-wide studies.

Exploring the effects of Hippo signaling pathway on rumen epithelial proliferation

BACKGROUND

The current understanding to the mechanism of rumen development is limited. We hypothesized that the Hippo signaling pathway controlled the proliferation of rumen epithelium (RE) during postnatal development. In the present study, we firstly tested the changes of the Hippo signaling pathway in the RE during an early growing period from d5 to d25, and then we expanded the time range to the whole preweaning period (d10-38) and one week post weaning (d45). An in vitro experiment was also carried out to verify the function of Hippo signaling pathway during RE cell proliferation.

RESULTS

In the RE of lambs from d5 to d25, the expression of baculoviral IAP repeat containing (BIRC3/5) was increased, while the expressions of large tumor suppressor kinase 2 (LATS2), TEA domain transcription factor 3 (TEAD3), axin 1 (AXIN1), and MYC proto-oncogene (MYC) were decreased with rumen growth. From d10 to d38, the RE expressions of BIRC3/5 were increased, while the expressions of LATS2 and MYC were decreased, which were similar with the changes in RE from d5 to d25. From d38 to d45, different changes were observed, with the expressions of LATS1/2, MOB kinase activator 1B (MOB1B), and TEAD1 increased, while the expressions of MST1 and BIRC5 decreased. Correlation analysis showed that during the preweaning period, the RE expressions of BIRC3/5 were positively correlated with rumen development variables, while LAST2 was negatively correlated with rumen development variables. The in vitro experiment validated the changes of LATS2 and BIRC3/5 in the proliferating RE cells, which supported their roles in RE proliferation during preweaning period.

CONCLUSIONS

Our results suggest that the LATS2-YAP1-BIRC3/5 axis participates in the RE cell proliferation and promotes rumen growth during the preweaning period.

Repression of developmental transcription factor networks triggers aging-associated gene expression in human glial progenitor cells

Human glial progenitor cells (hGPCs) exhibit diminished expansion competence with age, as well as after recurrent demyelination. Using RNA-sequencing to compare the gene expression of fetal and adult hGPCs, we identify age-related changes in transcription consistent with the repression of genes enabling mitotic expansion, concurrent with the onset of aging-associated transcriptional programs. Adult hGPCs develop a repressive transcription factor network centered on MYC, and regulated by ZNF274, MAX, IKZF3, and E2F6. Individual over-expression of these factors in iPSC-derived hGPCs lead to a loss of proliferative gene expression and an induction of mitotic senescence, replicating the transcriptional changes incurred during glial aging. miRNA profiling identifies the appearance of an adult-selective miRNA signature, imposing further constraints on the expansion competence of aged GPCs. hGPC aging is thus associated with acquisition of a MYC-repressive environment, suggesting that suppression of these repressors of glial expansion may permit the rejuvenation of aged hGPCs.

Targeting c-Myc with decoy oligodeoxynucleotide-loaded polycationic nanoparticles inhibits cell growth and induces apoptosis in cancer stem-like cells (NTERA-2)

BACKGROUND

An increase in cancer stem cell (CSC) populations and their resistance to common treatments could be a result of c-Myc dysregulations in certain cancer cells. In the current study, we investigated anticancer effects of c-Myc decoy ODNs loaded-poly (methacrylic acid-co-diallyl dimethyl ammonium chloride) (PMA-DDA)-coated silica nanoparticles as carriers on cancer-like stem cells (NTERA-2).

METHODS AND RESULTS

The physicochemical characteristics of the synthesized nanocomposites (SiO2@PMA-DDA-DEC) were analyzed using FT-IR, DLS, and SEM techniques. UV-Vis spectrophotometer was applied to analyze the release pattern of decoy ODNs from the nanocomposite. Furthermore, uptake, cell viability, apoptosis, and cell cycle assays were used to investigate the anticancer effects of nanocomposites loaded with c-Myc decoy ODNs on NTERA-2 cancer cells. The results of physicochemical analytics demonstrated that SiO2@PMA-DDA-DEC nanocomposites were successfully synthesized. The prepared nanocomposites were taken up by NTERA-2 cells with high efficiency, and could effectively inhibit cell growth and increase apoptosis rate in the treated cells compared to the control group. Moreover, SiO2@PMA-DDA nanocomposites loaded with c-Myc decoy ODNs induced cell cycle arrest at the G0/G1 phase in the treated cells.

CONCLUSIONS

The conclusion drawn from this study is that c-Myc decoy ODN-loaded SiO2@PMA-DDA nanocomposites can effectively inhibit cell growth and induce apoptosis in NTERA-2 cancer cells. Moreover, given that a metal core is incorporated into this synthetic nanocomposite, it could potentially be used in conjunction with irradiation as part of a decoy-radiotherapy combinational therapy in future investigations.

Characterization of cell cycle, inflammation, and oxidative stress signaling role in non-communicable diseases: Insights into genetic variants, microRNAs and pathways

Non-Communicable Diseases (NCDs) significantly impact global health, contributing to over 70% of premature deaths, as reported by the World Health Organization (WHO). These diseases have complex and multifactorial origins, involving genetic, epigenetic, environmental and lifestyle factors. While Genome-Wide Association Study (GWAS) is widely recognized as a valuable tool for identifying variants associated with complex phenotypes; the multifactorial nature of NCDs necessitates a more comprehensive exploration, encompassing not only the genetic but also the epigenetic aspect. For this purpose, we employed a bioinformatics-multiomics approach to examine the genetic and epigenetic characteristics of NCDs (i.e. colorectal cancer, coronary atherosclerosis, squamous cell lung cancer, psoriasis, type 2 diabetes, and multiple sclerosis), aiming to identify novel biomarkers for diagnosis and prognosis. Leveraging GWAS summary statistics, we pinpointed Single Nucleotide Polymorphisms (SNPs) independently associated with each NCD. Subsequently, we identified genes linked to cell cycle, inflammation and oxidative stress mechanisms, revealing shared genes across multiple diseases, suggesting common functional pathways. From an epigenetic perspective, we identified microRNAs (miRNAs) with regulatory functions targeting these genes of interest. Our findings underscore critical genetic pathways implicated in these diseases. In colorectal cancer, the dysregulation of the "Cytokine Signaling in Immune System" pathway, involving LAMA5 and SMAD7, regulated by Hsa-miR-21-5p, Hsa-miR-103a-3p, and Hsa-miR-195-5p, emerged as pivotal. In coronary atherosclerosis, the pathway associated with "binding of TCF/LEF:CTNNB1 to target gene promoters" displayed noteworthy implications, with the MYC factor controlled by Hsa-miR-16-5p as a potential regulatory factor. Squamous cell lung carcinoma analysis revealed significant pathways such as "PTK6 promotes HIF1A stabilization," regulated by Hsa-let-7b-5p. In psoriasis, the "Endosomal/Vacuolar pathway," involving HLA-C and Hsa-miR-148a-3p and Hsa-miR-148b-3p, was identified as crucial. Type 2 Diabetes implicated the "Regulation of TP53 Expression" pathway, controlled by Hsa-miR-106a-5p and Hsa-miR-106b-5p. In conclusion, our study elucidates the genetic framework and molecular mechanisms underlying NCDs, offering crucial insights into potential genetic/epigenetic biomarkers for diagnosis and prognosis. The specificity of pathways and related miRNAs in different pathologies highlights promising candidates for further clinical validation, with the potential to advance personalized treatments and alleviate the global burden of NCDs.

A Metastatic Cancer Expression Generator (MetGen): A Generative Contrastive Learning Framework for Metastatic Cancer Generation

Despite significant advances in tumor biology and clinical therapeutics, metastasis remains the primary cause of cancer-related deaths. While RNA-seq technology has been used extensively to study metastatic cancer characteristics, challenges persist in acquiring adequate transcriptomic data. To overcome this challenge, we propose MetGen, a generative contrastive learning tool based on a deep learning model. MetGen generates synthetic metastatic cancer expression profiles using primary cancer and normal tissue expression data. Our results demonstrate that MetGen generates comparable samples to actual metastatic cancer samples, and the cancer and tissue classification yields performance rates of 99.8 ± 0.2% and 95.0 ± 2.3%, respectively. A benchmark analysis suggests that the proposed model outperforms traditional generative models such as the variational autoencoder. In metastatic subtype classification, our generated samples show 97.6% predicting power compared to true metastatic samples. Additionally, we demonstrate MetGen's interpretability using metastatic prostate cancer and metastatic breast cancer. MetGen has learned highly relevant signatures in cancer, tissue, and tumor microenvironments, such as immune responses and the metastasis process, which can potentially foster a more comprehensive understanding of metastatic cancer biology. The development of MetGen represents a significant step toward the study of metastatic cancer biology by providing a generative model that identifies candidate therapeutic targets for the treatment of metastatic cancer.

Comparative transcriptional analysis identifies genes associated with the attenuation of Theileria parva infected cells after long-term in vitro culture

Autologous administration of attenuated Theileria parva-infected cells induces immunity to T. parva in cattle. The mechanism of attenuation, however, is largely unknown. Here, we used RNA sequencing of pathogenic and attenuated T. parva-infected T-cells to elucidate the transcriptional changes underpinning attenuation. We observed differential expression of several host genes, including TRAIL, PD-1, TGF-β and granzymes that are known to regulate inflammation and proliferation of infected cells. Importantly, many genes linked with the attenuation of the related T. annulata-infected cells were not dysregulated in this study. Furthermore, known T. parva antigens were not dysregulated in attenuated relative to pathogenic cells, indicating that attenuation is not due to enhanced immunogenicity. Overall this study suggests that attenuation is driven by a decrease in proliferation and restoration of the inflammatory profile of T. parva-infected cells. Additionally, it provides a foundation for future mechanistic studies of the attenuation phenotype in Theileria-infected cells.

CBX7 reprograms metabolic flux to protect against meningioma progression by modulating the USP44/c-MYC/LDHA axis

Meningioma is one of the most common primary neoplasms in the central nervous system, but no specific molecularly targeted therapy has been approved for the clinical treatment of aggressive meningiomas. There is hence an urgent demand to decrypt the biological and molecular landscape of malignant meningioma. Here, through the in-silica prescreening and 10-year follow-up studies of 445 meningioma patients, we uncovered that CBX7 expression progressively decreases with malignancy grade and neoplasia stage in meningioma, and a high CBX7 expression level predicts a favorable prognosis in meningioma patients. CBX7 restoration significantly induces cell cycle arrest and inhibits meningioma cell proliferation. iTRAQ-based proteomics analysis indicated that CBX7 restoration triggers the metabolic shift from glycolysis to oxidative phosphorylation. The mechanistic study demonstrated that CBX7 promotes the proteasome-dependent degradation of c-MYC protein by transcriptionally inhibiting the expression of a c-MYC deubiquitinase, USP44, consequently attenuates c-MYC-mediated transactivation of LDHA transcripts, and further inhibits glycolysis and subsequent cell proliferation. More importantly, the functional role of CBX7 was further confirmed in subcutaneous and orthotopic meningioma xenograft mouse models and meningioma patients. Altogether, our results shed light on the critical role of CBX7 in meningioma malignancy progression and identify the CBX7/USP44/c-MYC/LDHA axis as a promising therapeutic target against meningioma progression.

The pivotal role of irradiation-induced apoptosis in the pathogenesis and therapy of medulloblastoma

BACKGROUND

Medulloblastoma (MB) is a rare primitive neuroectodermal tumors originating from the cerebellum. MB is the most common malignant primary brain tumor of childhood. MB originates from neural precursor cells in distinctive regions of the rhombic lip, and their maturation occurs in the cerebellum or the brain stem during embryonal development. Also, apoptosis is a programmed cell death associated with numerous physiological as well as pathological regulations.

RECENT FINDINGS

Irradiation (IR)-induce apoptosis triggers cell death, with or without intervening mitosis within a few hours of IR and these share different morphologic alteration such as, loss of normal nuclear structure as well as degradation of DNA. Moreover, MB is strikingly sensitive to DNA-damaging therapies and the role of apoptosis a key treatment modality. Furthermore, in MB, the apoptotic pathways are made up of several triggers, modulators, as well as effectors. Notably, IR-induced apoptotic mechanisms in MB therapy are very complex and they either induce radiosensitivity or inhibit radioresistance leading to potential effective treatment strategies for MB.

CONCLUSION

This review explicitly explores the pivotal roles of IR-induced apoptosis in the pathogenesis and therapy of MB.

MYC Oncogene: A Druggable Target for Treating Cancers with Natural Products

Various diseases, including cancers, age-associated disorders, and acute liver failure, have been linked to the oncogene, MYC. Animal testing and clinical trials have shown that sustained tumor volume reduction can be achieved when MYC is inactivated, and different combinations of therapeutic agents including MYC inhibitors are currently being developed. In this review, we first provide a summary of the multiple biological functions of the MYC oncoprotein in cancer treatment, highlighting that the equilibrium points of the MYC/MAX, MIZ1/MYC/MAX, and MAD (MNT)/MAX complexes have further potential in cancer treatment that could be used to restrain MYC oncogene expression and its functions in tumorigenesis. We also discuss the multifunctional capacity of MYC in various cellular cancer processes, including its influences on immune response, metabolism, cell cycle, apoptosis, autophagy, pyroptosis, metastasis, angiogenesis, multidrug resistance, and intestinal flora. Moreover, we summarize the MYC therapy patent landscape and emphasize the potential of MYC as a druggable target, using herbal medicine modulators. Finally, we describe pending challenges and future perspectives in biomedical research, involving the development of therapeutic approaches to modulate MYC or its targeted genes. Patients with cancers driven by MYC signaling may benefit from therapies targeting these pathways, which could delay cancerous growth and recover antitumor immune responses.

The 24-Hour Time Course of Integrated Molecular Responses to Resistance Exercise in Human Skeletal Muscle Implicates MYC as a Hypertrophic Regulator That is Sufficient for Growth

Molecular control of recovery after exercise in muscle is temporally dynamic. A time course of biopsies around resistance exercise (RE) combined with -omics is necessary to better comprehend the molecular contributions of skeletal muscle adaptation in humans. Vastus lateralis biopsies before and 30 minutes, 3-, 8-, and 24-hours after acute RE were collected. A time-point matched biopsy-only group was also included. RNA-sequencing defined the transcriptome while DNA methylomics and computational approaches complemented these data. The post-RE time course revealed: 1) DNA methylome responses at 30 minutes corresponded to upregulated genes at 3 hours, 2) a burst of translation- and transcription-initiation factor-coding transcripts occurred between 3 and 8 hours, 3) global gene expression peaked at 8 hours, 4) ribosome-related genes dominated the mRNA landscape between 8 and 24 hours, 5) methylation-regulated MYC was a highly influential transcription factor throughout the 24-hour recovery and played a primary role in ribosome-related mRNA levels between 8 and 24 hours. The influence of MYC in human muscle adaptation was strengthened by transcriptome information from acute MYC overexpression in mouse muscle. To test whether MYC was sufficient for hypertrophy, we generated a muscle fiber-specific doxycycline inducible model of pulsatile MYC induction. Periodic 48-hour pulses of MYC over 4 weeks resulted in higher muscle mass and fiber size in the soleus of adult female mice. Collectively, we present a temporally resolved resource for understanding molecular adaptations to RE in muscle and reveal MYC as a regulator of RE-induced mRNA levels and hypertrophy.

Advances in the antitumor mechanisms of tripartite motif-containing protein 3

The tripartite motif-containing (TRIM) protein family has steadily become a hotspot in tumor-related research. As a member of the E3 ubiquitin ligase family, TRIM is working on many crucial biological processes, including the regulation of tumor cell proliferation, metastasis, apoptosis, and autophagy. Among the diverse TRIM superfamily members, TRIM3 operates via different mechanisms in various types of tumors. This review primarily focuses on the current state of research regarding the antitumor mechanisms of TRIM3 in different cancers. A more in-depth study of TRIM3 may provide new directions for future antitumor treatments. Our review focuses on TRIM3 proteins and cancer. We searched for relevant articles on the mechanisms by which TRIM3 affects tumorigenesis and development from 1997 to 2023 and summarized the latest progress and future directions. Triad-containing motif protein 3 (TRIM3) is an important protein, which plays a key role in the process of tumorigenesis and development. The comprehensive exploration of TRIM3 is anticipated to pave the way for future advancements in antitumor therapy, which is expected to be a new hallmark for cancer detection and a novel target for drug action. TRIM3 is poised to become a significant milestone in cancer detection and a promising focal point for drug intervention. Recent years have witnessed notable progress in research aimed at unraveling the antitumor mechanism of TRIM3, with far-reaching implications for practical tumor diagnosis, treatment protocols, efficacy evaluation, economics, and pharmaceutical utilization.

Elevated expression of HIGD1A drives hepatocellular carcinoma progression by regulating polyamine metabolism through c-Myc-ODC1 nexus

BACKGROUND

Hypoxia contributes to cancer progression through various molecular mechanisms and hepatocellular carcinoma (HCC) is one of the most hypoxic malignancies. Hypoxia-inducible gene domain protein-1a (HIGD1A) is typically induced via epigenetic regulation and promotes tumor cell survival during hypoxia. However, the role of HIGD1A in HCC remains unknown.

METHODS

HIGD1A expression was determined in 24 pairs of human HCC samples and para-tumorous tissues. Loss-of-function experiments were conducted both in vivo and in vitro to explore the role of HIGD1A in HCC proliferation and metastasis.

RESULTS

Increased HIGD1A expression was found in HCC tissues and cell lines, which was induced by hypoxia or low-glucose condition. Moreover, HIGD1A knockdown in HCC cells arrested the cell cycle at the G2/M phase and promoted hypoxia-induced cell apoptosis, resulting in great inhibition of cell proliferation, migration, and invasion, as well as tumor xenograft formation. Interestingly, these anti-tumor effects were not observed in normal hepatocyte cell line L02. Further, HIGD1A knockdown suppressed the expression of ornithine decarboxylase 1 (ODC1), a rate-limiting enzyme of polyamine metabolism under c-Myc regulation. HIGD1A was found to bind with the c-Myc promoter region, and its knockdown decreased the levels of polyamine metabolites. Consistently, the inhibitory effect on HCC phenotype by HIGD1A silencing could be reversed by overexpression of c-Myc or supplementation of polyamines.

CONCLUSIONS

Our results demonstrated that HIGD1A activated c-Myc-ODC1 nexus to regulate polyamine synthesis and to promote HCC survival and malignant phenotype, implying that HIGD1A might represent a novel therapeutic target for HCC.

HDAC Inhibition Induces CD26 Expression on Multiple Myeloma Cells via the c-Myc/Sp1-mediated Promoter Activation

CD26 is ubiquitously and intensely expressed in osteoclasts in patients with multiple myeloma, whereas its expression in plasma cells of patients with multiple myeloma is heterogeneous because of its cellular diversity, immune escape, and disease progression. Decreased expression levels of CD26 in myeloma cells constitute one of the mechanisms underlying resistance to humanized anti-CD26 mAb therapy in multiple myeloma. In the current study, we show that histone deacetylase inhibition (HDACi) with broad or class-specific inhibitors involves the induction of CD26 expression on CD26neg myeloma cells both transcriptionally and translationally. Furthermore, dipeptidyl peptidase Ⅳ (DPPⅣ) enzymatic activity was concomitantly enhanced in myeloma cells. Combined treatment with HDACi plus CD26mAb synergistically facilitated lysis of CD26neg myeloma cells not only by antibody-dependent cellular cytotoxicity but also by the direct effects of mAb. Of note, its combination readily augmented lysis of CD26neg cell populations, refractory to CD26mAb or HDACi alone. Chromatin immunoprecipitation assay revealed that HDACi increased acetylation of histone 3 lysine 27 at the CD26 promoter of myeloma cells. Moreover, in the absence of HDACi, c-Myc was attached to the CD26 promoter via Sp1 on the proximal G-C box of myeloma cells, whereas, in the presence of HDACi, c-Myc was detached from Sp1 with increased acetylation of c-Myc on the promoter, leading to activation of the CD26 promoter and initiation of transcription in myeloma cells. Collectively, these results confirm that HDACi plays crucial roles not only through its anti-myeloma activity but by sensitizing CD26neg myeloma cells to CD26mAb via c-Myc/Sp1-mediated CD26 induction, thereby augmenting its cytotoxicity.

SIGNIFICANCE

There is a desire to induce and sustain CD26 expression on multiple myeloma cells to elicit superior anti-myeloma response by humanized anti-CD26 mAb therapy. HDACi upregulates the expression levels of CD26 on myeloma cells via the increased acetylation of c-MycK323 on the CD26 promoter, leading to initiation of CD26 transcription, thereby synergistically augments the efficacy of CD26mAb against CD26neg myeloma cells.

ANGPTL4 regulates ovarian cancer progression by activating the ERK1/2 pathway

BACKGROUND

Ovarian cancer (OC) has the highest mortality rate among all gynecological malignancies. A hypoxic microenvironment is a common feature of solid tumors, including ovarian cancer, and an important driving factor of tumor cell survival and chemo- and radiotherapy resistance. Previous research identified the hypoxia-associated gene angiopoietin-like 4 (ANGPTL4) as both a pro-angiogenic and pro-metastatic factor in tumors. Hence, this work aimed to further elucidate the contribution of ANGPTL4 to OC progression.

METHODS

The expression of hypoxia-associated ANGPTL4 in human ovarian cancer was examined by bioinformatics analysis of TCGA and GEO datasets. The CIBERSORT tool was used to analyze the distribution of tumor-infiltrating immune cells in ovarian cancer cases in TCGA. The effect of ANGPTL4 silencing and overexpression on the proliferation and migration of OVCAR3 and A2780 OC cells was studied in vitro, using CCK-8, colony formation, and Transwell assays, and in vivo, through subcutaneous tumorigenesis assays in nude mice. GO enrichment analysis and WGCNA were performed to explore biological processes and genetic networks associated with ANGPTL4. The results obtained were corroborated in OC cells in vitro by western blotting.

RESULTS

Screening of hypoxia-associated genes in OC-related TCGA and GEO datasets revealed a significant negative association between ANGPTL4 expression and patient survival. Based on CIBERSORT analysis, differential representation of 14 distinct tumor-infiltrating immune cell types was detected between low- and high-risk patient groups. Silencing of ANGPTL4 inhibited OVCAR3 and A2780 cell proliferation and migration in vitro and reduced the growth rate of xenografted OVCAR3 cells in vivo. Based on results from WGCNA and previous studies, western blot assays in cultured OC cells demonstrated that ANGPTL4 activates the Extracellular signal-related kinases 1 and 2 (ERK1/2) pathway and this results in upregulation of c-Myc, Cyclin D1, and MMP2 expression. Suggesting that the above mechanism mediates the pro-oncogenic actions of ANGPTL4T in OC, the pro-survival effects of ANGPTL4 were largely abolished upon inhibition of ERK1/2 signaling with PD98059.

CONCLUSIONS

Our work suggests that the hypoxia-associated gene ANGPTL4 stimulates OC progression through activation of the ERK1/2 pathway. These findings may offer a new prospect for targeted therapies for the treatment of OC.

The ways Fusobacterium nucleatum translocate to breast tissue and contribute to breast cancer development

Breast cancer is among the most prevalent malignancies in women worldwide. Epidemiological findings suggested that periodontal diseases may be associated with breast cancer, among which Fusobacterium nucleatum is considered an important cross-participant. In this work, we comprehensively summarize the known mechanisms of how F. nucleatum translocates to, colonizes in mammary tumors, and promotes the carcinogenesis. Specifically, F. nucleatum translocates to mammary tissue through the mammary-intestinal axis, direct nipple contact, and hematogenous transmission. Subsequently, F. nucleatum takes advantage of fusobacterium autotransporter protein 2 to colonize breast cancer and uses virulence factors fusobacterium adhesin A and lipopolysaccharide to promote proliferation. Moreover, the upregulated matrix metalloproteinase-9 induced by F. nucleatum does not only trigger the inflammatory response but also facilitates the tumor-promoting microenvironment. Aside from the pro-inflammatory effect, F. nucleatum may also be engaged in tumor immune evasion, which is achieved through the action of virulence factors on immune checkpoint receptors highly expressed on T cells, natural killer cells, and tumor-infiltrating lymphocytes. Taking breast cancer as an example, more relevant research studies may expand our current knowledge of how oral microbes affect systemic health. Hopefully, exploring these mechanisms in depth could provide new strategies for safer and more effective biologic and targeted therapies targeted at breast cancer.

Identification of MYC intron 2 regions that modulate expression

MYC pre-mRNA is spliced with high fidelity to produce the transcription factor known to regulate cellular differentiation, proliferation, apoptosis, and alternative splicing. The mechanisms underpinning the pre-mRNA splicing of MYC, however, remain mostly unexplored. In this study, we examined the interaction of heterogeneous nuclear ribonucleoprotein C (HNRNPC) with MYC intron 2. Building off published eCLIP studies, we confirmed this interaction with poly(U) regions in intron 2 of MYC and found that full binding is correlated with optimal protein production. The interaction appears to be compensatory, as mutational disruption of all three poly(U) regions was required to reduce both HNRNPC binding capacity and fidelity of either splicing or translation. Poly(U) sequences in MYC intron 2 were relatively conserved across sequences from several different species. Lastly, we identified a short sequence just upstream of an HNRNPC binding region that when removed enhances MYC translation.

Therapeutic potential of anti-PIK3CG treatment for multiple myeloma via inhibiting c-Myc pathway

Multiple myeloma (MM) is a malignant plasma cell disease. The activity of PIK3CG (PI3K catalytic subunit γ) is regulated directly by G-protein-coupled receptor and has been confirmed to be highly expressed in MM cells. This study aimed to determine the effect of pharmacological inhibition of PIK3CG on MM. We found that different concentrations of the PIK3CG inhibitor AS-605240 could suppress the growth of MM cell lines and the expression of c-Myc. The combination of PIK3CG inhibitor and the chemotherapy Melphalan could effectively inhibit the proliferation and migration of MM cells, promote the cell apoptosis, and decrease the ratio of Bcl-2/Bax and the expression of vimentin. The expression of proto-oncogene c-Myc was decreased and the sensitivity of cells to chemotherapeutic drugs was enhanced. Collectively, PIK3CG regulates growth of MM via c-Myc pathway, thus emerging as a promising molecular targeted therapy.

Multifaceted roles for BCL3 in cancer: a proto-oncogene comes of age

In the early 1990's a group of unrelated genes were identified from the sites of recurring translocations in B-cell lymphomas. Despite sharing the nomenclature 'Bcl', and an association with blood-borne cancer, these genes have unrelated functions. Of these genes, BCL2 is best known as a key cancer target involved in the regulation of caspases and other cell viability mechanisms. BCL3 on the other hand was originally identified as a non-canonical regulator of NF-kB transcription factor pathways - a signaling mechanism associated with important cell outcomes including many of the hallmarks of cancer. Most of the early investigations into BCL3 function have since focused on its role in NF-kB mediated cell proliferation, inflammation/immunity and cancer. However, recent evidence is coming to light that this protein directly interacts with and modulates a number of other signaling pathways including DNA damage repair, WNT/β-catenin, AKT, TGFβ/SMAD3 and STAT3 - all of which have key roles in cancer development, metastatic progression and treatment of solid tumours. Here we review the direct evidence demonstrating BCL3's central role in a transcriptional network of signaling pathways that modulate cancer biology and treatment response in a range of solid tumour types and propose common mechanisms of action of BCL3 which may be exploited in the future to target its oncogenic effects for patient benefit.

Natural STAT3 Inhibitors for Cancer Treatment: A Comprehensive Literature Review

Cancer is one of the leading causes of mortality and morbidity worldwide, affecting millions of people physically and financially every year. Over time, many anticancer treatments have been proposed and studied, including synthetic compound consumption, surgical procedures, or grueling chemotherapy. Although these treatments have improved the daily life quality of patients and increased their survival rate and life expectancy, they have also shown significant drawbacks, including staggering costs, multiple side effects, and difficulty in compliance and adherence to treatment. Therefore, natural compounds have been considered a possible key to overcoming these problems in recent years, and thorough research has been done to assess their effectiveness. In these studies, scientists have discovered a meaningful interaction between several natural materials and signal transducer and activator of transcription 3 molecules. STAT3 is a transcriptional protein that is vital for cell growth and survival. Mechanistic studies have established that activated STAT3 can increase cancer cell proliferation and invasion while reducing anticancer immunity. Thus, inhibiting STAT3 signaling by natural compounds has become one of the favorite research topics and an attractive target for developing novel cancer treatments. In the present article, we intend to comprehensively review the latest knowledge about the effects of various organic compounds on inhibiting the STAT3 signaling pathway to cure different cancer diseases.

Energy metabolism modulates the regulatory impact of activators on gene expression

Gene expression is a regulated process fueled by ATP consumption. Therefore, regulation must be coupled to constraints imposed by the level of energy metabolism. Here, we explore this relationship both theoretically and experimentally. A stylized mathematical model predicts that activators of gene expression have variable impact depending on metabolic rate. Activators become less essential when metabolic rate is reduced and more essential when metabolic rate is enhanced. We find that, in the Drosophila eye, expression dynamics of the yan gene are less affected by loss of EGFR-mediated activation when metabolism is reduced, and the opposite effect is seen when metabolism is enhanced. The effects are also seen at the level of pattern regularity in the adult eye, where loss of EGFR-mediated activation is mitigated by lower metabolism. We propose that gene activation is tuned by energy metabolism to allow for faithful expression dynamics in the face of variable metabolic conditions.

Transcriptional activation of the Myc gene by glucose in β-cells requires a ChREBP-dependent 3-D chromatin interaction between the Myc and Pvt1 genes

OBJECTIVE

All forms of diabetes result from insufficient functional β-cell mass. Thus, achieving the therapeutic goal of expanding β-cell mass requires a better mechanistic understanding of how β-cells proliferate. Glucose is a natural β-cell mitogen that mediates its effects in part through the glucose-responsive transcription factor, carbohydrate response element binding protein (ChREBP) and the anabolic transcription factor, MYC. However, mechanistic details by which glucose activates Myc at the transcriptional level are poorly understood.

METHODS

Here, siRNA was used to test the role of ChREBP in the glucose response of MYC, ChIP and ChIPseq to identify potential regulatory binding sites, chromatin conformation capture to identify DNA/DNA interactions, and an adenovirus was constructed to expresses x-dCas9 and an sgRNA that specifically disrupts the recruitment of ChREBP to a specific targeted ChoRE.

RESULTS

We found that ChREBP is essential for glucose-mediated transcriptional induction of Myc, and for increases in Myc mRNA and protein abundance. Further, ChIPseq revealed that the carbohydrate response element (ChoRE) nearest to the Myc transcriptional start site (TSS) is immediately upstream of the gene encoding the lncRNA, Pvt1, 60,000 bp downstream of the Myc gene. Chromatin Conformation Capture (3C) confirmed a glucose-dependent interaction between these two sites. Transduction with an adenovirus expressing x-dCas9 and an sgRNA specifically targeting the highly conserved Pvt1 ChoRE, attenuates ChREBP recruitment, decreases Myc-Pvt1 DNA/DNA interaction, and decreases expression of the Pvt1 and Myc genes in response to glucose. Importantly, isolated and dispersed rat islet cells transduced with the ChoRE-disrupting adenovirus also display specific decreases in ChREBP-dependent, glucose-mediated expression of Pvt1 and Myc, as well as decreased glucose-stimulated β-cell proliferation.

CONCLUSIONS

The mitogenic glucose response of Myc is mediated via glucose-dependent recruitment of ChREBP to the promoter of the Pvt1 gene and subsequent DNA looping with the Myc promoter.

Polyamine Dysregulation and Nucleolar Disruption in Alzheimer's Disease

A hypothesis of Alzheimer's disease etiology is proposed describing how cellular stress induces excessive polyamine synthesis and recycling which can disrupt nucleoli. Polyamines are essential in nucleolar functions, such as RNA folding and ribonucleoprotein assembly. Changes in the nucleolar pool of anionic RNA and cationic polyamines acting as counterions can cause significant nucleolar dynamics. Polyamine synthesis reduces S-adenosylmethionine which, at low levels, triggers tau phosphorylation. Also, polyamine recycling reduces acetyl-CoA needed for acetylcholine, which is low in Alzheimer's disease. Extraordinary nucleolar expansion and/or contraction can disrupt epigenetic control in peri-nucleolar chromatin, such as chromosome 14 with the presenilin-1 gene; chromosome 21 with the amyloid precursor protein gene; chromosome 17 with the tau gene; chromosome 19 with the APOE4 gene; and the inactive X chromosome (Xi; aka "nucleolar satellite") with normally silent spermine synthase (polyamine synthesis) and spermidine/spermine-N1-acetyltransferase (polyamine recycling) alleles. Chromosomes 17, 19 and the Xi have high concentrations of Alu elements which can be transcribed by RNA polymerase III if positioned nucleosomes are displaced from the Alu elements. A sudden flood of Alu RNA transcripts can competitively bind nucleolin which is usually bound to Alu sequences in structural RNAs that stabilize the nucleolar heterochromatic shell. This Alu competition leads to loss of nucleolar integrity with leaking of nucleolar polyamines that cause aggregation of phosphorylated tau. The hypothesis was developed with key word searches (e.g., PubMed) using relevant terms (e.g., Alzheimer's, lupus, nucleolin) based on a systems biology approach and exploring autoimmune disease tautology, gaining synergistic insights from other diseases.

Novel Perspectives for the Diagnosis and Treatment of Gynecological Cancers using Dysregulation of PIWI Protein and PiRNAs as Biomarkers

The term "gynecological cancer" is used for a group of cancers occurring in the female reproductive system. Some of these cancers are ranked as the leading causes of death in developed and developing countries. The lack of proper diagnostic strategies is one of the most important reasons that make them lethal. PIWI-interacting RNAs or piRNAs are a class of small non-coding RNAs, which contain 24-32 nucleotides. These RNAs take part in some cellular mechanisms, and their role in diverse kinds of cancer is confirmed by accumulative evidence. In this review, we gather some information on the roles of these RNAs and members of the PIWI protein family to provide new insight into accurate diagnostic biomarkers and more effective anti-cancer drugs with fewer side effects.

Structure-guided screening of protein-protein interaction for the identification of Myc-Max heterodimer complex modulators

De-regulation of oncogenic myelocytomatosis (c-Myc or Myc) transcription factor is one of the most common molecular anomalies encountered in human cancers, and it is typically linked to many aggressive malignancies including breast, lung, cervix, colon glioblastomas, and other haematological organs. The Myc belongs to the basic helix-loop-helix zipper protein family (bHLH-ZIP), and its dimerization with another principal interactor protein partner Myc-associated factor X (Max) is essentially required for cellular transformation, cell growth and proliferation, and transcriptional activation. Intermolecular interactions have been evaluated between hetero-dimer Myc-Max protein, which identified protein-protein interaction (PPI) specific modulators using highly précised molecular docking study followed by long-range interaction stability analyzed through molecular dynamic (MD) simulation. Moreover, ADME profile analyses have been estimated for screened hit compounds. MM-GBSA-based binding free energy (ΔG) estimations have been performed for all screened hit compounds obtained from multi-step molecular docking-based virtual screening technique. According to the employed various rigorous multi-chemometric techniques, four identified inhibitors/modulators appear to have a considerable number of intermolecular contacts with hotspot residues in the hetero-dimer interface region of the Myc-Max PPI complex. However, identified hit compounds might need further structural optimization or extensive biophysical analyses for better understanding of the molecular mechanism for exhibiting the Myc-Max PPI interface binding stability.Communicated by Ramaswamy H. Sarma.

Acetylcorynoline Induces Apoptosis and G2/M Phase Arrest through the c-Myc Signaling Pathway in Colon Cancer Cells

Colorectal cancer (CRC) is the third most commonly diagnosed cancer worldwide, and despite advances in treatment, survival rates are still low; therefore, the development of novel drugs is imperative. Acetylcorynoline (ACN) is derived from Corydalis ambigua Cham. et Schltdl tubers. The effect of ACN on colon cancer is still unknown. Therefore, we investigated its potential effects. Our data showed that ACN inhibited cell viability and proliferation. Moreover, ACN induced apoptosis and cell cycle arrest by inhibiting cell growth. In the present study, we hypothesized that ACN regulates c-Myc through CNOT2 or MID1IP1. ACN reduced the protein expression of oncogenic genes, decreased c-Myc half-life, and rapidly inhibited the serum stimulation response. Moreover, knockdown of CNOT2 and MID1IP1 with ACN increased apoptosis and further reduced the expression of oncogenes. In addition, ACN exhibited a synergistic effect with low-dose 5-fluorouracil (5-FU) and doxorubicin (Dox). Collectively, our data demonstrate that ACN inhibited c-Myc expression through CNOT2 and MID1IP1, and induced apoptosis. These findings indicate the potential of ACN as a therapeutic agent against colon cancer.

Detection of the DNA binding of transcription factors in situ at the single-cell resolution in cultured cells by proximity ligation assay

Transcription factors (TFs) play a pivotal role in gene expression, and their DNA binding is the prerequisite to instigating gene transcription. Here, we present a protocol that exploits the proximity ligation assay technique to measure the DNA-binding activities of TFs in situ at the single-cell resolution. We describe steps for immunostaining with specific antibodies against double-stranded DNA and the TFs of interest, probe incubation, proximity ligation, and signal amplification. We then detail procedures for imaging and image analysis. For complete details on the use and execution of this protocol, please refer to Dai et al. (2015)1 and Xu et al. (2023).2.

Insights into the mechanism of binding of doxorubicin and a chlorin compound with 22-mer c-Myc G quadruplex

BACKGROUND

The interaction of small molecules with G quadruplexes is in focus due to its role in molecular recognition and therapeutic drug design. Stabilization of G-quadruplex structures in the promoter regions of oncogenes by small molecule binding has been demonstrated as a potential approach for cancer therapy.

METHODS

In this study, electronic spectroscopy (ultraviolet-visible, fluorescence, circular dichroism), differential scanning calorimetry, and molecular modeling were employed to explore the interactions between the chemotherapy drug doxorubicin and a chlorin compound 5,10,15,20-tetraphenyl-[2,3]-[bis(carboxy)-methano]chlorin (H2TPC(DAC)), and the c-Myc 22-mer G quadruplex DNA.

RESULTS

Spectroscopic studies indicated external binding of the compounds with partial stacking at the end quartets. Calorimetric studies and temperature dependent circular dichroism data displayed increased melting temperatures of G quadruplex structure on binding with the compounds. Circular dichroism spectra indicated that the G quadruplex structure is intact upon ligand binding. Both the compounds showed binding affinities of the order of 106 M-1. Fluorescence lifetime studies revealed static quenching as major mechanism for fluorescence quenching. Polymerase chain reaction stop assay hinted that binding of both ligands under study could inhibit the amplification of the DNA sequence.

CONCLUSION

Results show that doxorubicin and H2TPC(DAC) bind to the 22-mer c-Myc quadruplex structure with good affinity and induce stability.

SIGNIFICANCE

Doxorubicin and H2TPC(DAC) have demonstrated their affinity towards c-Myc G quadruplex DNA, stabilizing it and inhibiting expression and polymerization. The results can be of practical use in designing new analogs for the two compounds, which can become potent anti-cancer agents targeting the c-Myc GQ structure.

MiR-326-mediated overexpression of NFIB offsets TGF-β induced epithelial to mesenchymal transition and reverses lung fibrosis

Idiopathic Pulmonary Fibrosis (IPF) is a progressively fatal and incurable disease characterized by the loss of alveolar structures, increased epithelial-mesenchymal transition (EMT), and aberrant tissue repair. In this study, we investigated the role of Nuclear Factor I-B (NFIB), a transcription factor critical for lung development and maturation, in IPF. Using both human lung tissue samples from patients with IPF, and a mouse model of lung fibrosis induced by bleomycin, we showed that there was a significant reduction of NFIB both in the lungs of patients and mice with IPF. Furthermore, our in vitro experiments using cultured human lung cells demonstrated that the loss of NFIB was associated with the induction of EMT by transforming growth factor beta (TGF-β). Knockdown of NFIB promoted EMT, while overexpression of NFIB suppressed EMT and attenuated the severity of bleomycin-induced lung fibrosis in mice. Mechanistically, we identified post-translational regulation of NFIB by miR-326, a miRNA with anti-fibrotic effects that is diminished in IPF. Specifically, we showed that miR-326 stabilized and increased the expression of NFIB through its 3'UTR target sites for Human antigen R (HuR). Moreover, treatment of mice with either NFIB plasmid or miR-326 reversed airway collagen deposition and fibrosis. In conclusion, our study emphasizes the critical role of NFIB in lung development and maturation, and its reduction in IPF leading to EMT and loss of alveolar structures. Our study highlights the potential of miR-326 as a therapeutic intervention for IPF. The schema shows the role of NFIB in maintaining the normal epithelial cell characteristics in the lungs and how its reduction leads to a shift towards mesenchymal cell-like features and pulmonary fibrosis. A In normal lungs, NFIB is expressed abundantly in the epithelial cells, which helps in maintaining their shape, cell polarity and adhesion molecules. However, when the lungs are exposed to factors that induce pulmonary fibrosis, such as bleomycin, or TGF-β, the epithelial cells undergo epithelial to mesenchymal transition (EMT), which leads to a decrease in NFIB. B The mesenchymal cells that arise from EMT appear as spindle-shaped with loss of cell junctions, increased cell migration, loss of polarity and expression of markers associated with mesenchymal cells/fibroblasts. C We designed a therapeutic approach that involves exogenous administration of NFIB in the form of overexpression plasmid or microRNA-326. This therapeutic approach decreases the mesenchymal cell phenotype and restores the epithelial cell phenotype, thus preventing the development or progression of pulmonary fibrosis.

Transposable Elements Are Co-opted as Oncogenic Regulatory Elements by Lineage-Specific Transcription Factors in Prostate Cancer

Transposable elements hold regulatory functions that impact cell fate determination by controlling gene expression. However, little is known about the transcriptional machinery engaged at transposable elements in pluripotent and mature versus oncogenic cell states. Through positional analysis over repetitive DNA sequences of H3K27ac chromatin immunoprecipitation sequencing data from 32 normal cell states, we report pluripotent/stem and mature cell state-specific "regulatory transposable elements." Pluripotent/stem elements are binding sites for pluripotency factors (e.g., NANOG, SOX2, OCT4). Mature cell elements are docking sites for lineage-specific transcription factors, including AR and FOXA1 in prostate epithelium. Expanding the analysis to prostate tumors, we identify a subset of regulatory transposable elements shared with pluripotent/stem cells, including Tigger3a. Using chromatin editing technology, we show how such elements promote prostate cancer growth by regulating AR transcriptional activity. Collectively, our results suggest that oncogenesis arises from lineage-specific transcription factors hijacking pluripotent/stem cell regulatory transposable elements.

SIGNIFICANCE

We show that oncogenesis relies on co-opting transposable elements from pluripotent stem cells as regulatory elements altering the recruitment of lineage-specific transcription factors. We further discover how co-option is dependent on active chromatin states with important implications for developing treatment options against drivers of oncogenesis across the repetitive DNA. This article is featured in Selected Articles from This Issue, p. 2293.

Energy metabolism modulates the regulatory impact of activators on gene expression

Gene expression is a regulated process fueled by ATP consumption. Therefore, regulation must be coupled to constraints imposed by the level of energy metabolism. Here, we explore this relationship both theoretically and experimentally. A stylized mathematical model predicts that activators of gene expression have variable impact depending on metabolic rate. Activators become less essential when metabolic rate is reduced and more essential when metabolic rate is enhanced. We find that in the Drosophila eye, expression dynamics of the yan gene are less affected by loss of EGFR-mediated activation when metabolism is reduced, and the opposite effect is seen when metabolism is enhanced. The effects are also seen at the level of pattern regularity in the adult eye, where loss of EGFR-mediated activation is mitigated by lower metabolism. We propose that gene activation is tuned by energy metabolism to allow for faithful expression dynamics in the face of variable metabolic conditions.

Missense mutations in Myc Box I influence MYC cellular localization, mRNA partitioning and turnover to promote leukemogenesis

Somatic missense mutations in the phosphodegron domain of the MYC gene ( M YC Box I) are detected in the dominant clones of a subset of acute myeloid leukemia (AML) patients, but the mechanisms by which they contribute to AML are unknown. To unveil unique proprieties of MBI MYC mutant proteins, we systematically compared the cellular and molecular consequences of expressing similar oncogenic levels of wild type and MBI mutant MYC. We found that MBI MYC mutants can accelerate leukemia by driving unique transcriptional signatures in highly selected, myeloid progenitor subpopulations. Although these mutations increase MYC stability, they overall dampen MYC chromatin localization and lead to a cytoplasmic accumulation of the mutant proteins. This phenotype is coupled with increased translation of RNA binding proteins and nuclear export machinery, which results in altered RNA partitioning and accelerated decay of select transcripts encoding proapoptotic and proinflammatory genes. Heterozygous knockin mice harboring the germline MBI mutation Myc p.T73N exhibit cytoplasmic MYC localization, myeloid progenitors' expansion with similar transcriptional signatures to the overexpression model, and eventually develop hematological malignancies. This study uncovers that MBI MYC mutations alter MYC localization and disrupt mRNA subcellular distribution and turnover of select transcripts to accelerate tumor initiation and growth.

Comparative transcriptome analysis between long- and short-term survival after pig-to-monkey cardiac xenotransplantation reveals differential heart failure development

Cardiac xenotransplantation is the potential treatment for end-stage heart failure, but the allogenic organ supply needs to catch up to clinical demand. Therefore, genetically-modified porcine heart xenotransplantation could be a potential alternative. So far, pig-to-monkey heart xenografts have been studied using multi-transgenic pigs, indicating various survival periods. However, functional mechanisms based on survival period-related gene expression are unclear. This study aimed to identify the differential mechanisms between pig-to-monkey post-xenotransplantation long- and short-term survivals. Heterotopic abdominal transplantation was performed using a donor CD46-expressing GTKO pig and a recipient cynomolgus monkey. RNA-seq was performed using samples from POD60 XH from monkey and NH from age-matched pigs, D35 and D95. Gene-annotated DEGs for POD60 XH were compared with those for POD9 XH (Park et al. 2021). DEGs were identified by comparing gene expression levels in POD60 XH versus either D35 or D95 NH. 1,804 and 1,655 DEGs were identified in POD60 XH versus D35 NH and POD60 XH versus D95 NH, respectively. Overlapped 1,148 DEGs were annotated and compared with 1,348 DEGs for POD9 XH. Transcriptomic features for heart failure and inhibition of T cell activation were observed in both long (POD60)- and short (POD9)-term survived monkeys. Only short-term survived monkey showed heart remodeling and regeneration features, while long-term survived monkey indicated multi-organ failure by neural and hormonal signaling as well as suppression of B cell activation. Our results reveal differential heart failure development and survival at the transcriptome level and suggest candidate genes for specific signals to control adverse cardiac xenotransplantation effects.

c-MYC/METTL3/LINC01006 positive feedback loop promotes migration, invasion and proliferation of non-small cell lung cancer

BACKGROUND

This study aims to clarify the N6-methyladenosine (m6A) modification of LINC01006, which is involved in migration, invasion and proliferation of non-small cell lung cancer (NSCLC).

MATERIALS AND METHODS

LINC01006 and METTL3 expressions were analyzed in TCGA-LUAD cohort. Colony formation assay, wound-healing assay and transwell assay were performed to evaluate the ability of colony formation, migration and invasion. Q-PCR and western blot analysis determined gene expressions. M6A-RNA immunoprecipitation and m6A quantification assay were used to evaluate m6A modification. qChIP assay was used to validate transcriptional target. Luciferase assay validated the miRNA targets and transcriptional targets. In-situ xenograft model were included to evaluate tumor proliferation in vivo.

RESULTS

LINC01006 and METTL3 expressions were elevated in NSCLC cells and tissues. LINC01006 promoted the migration and invasion of NSCLC via epithelial - mesenchymal transition (EMT). The expression of LINC01006 was positively correlated to the expression of METTL3. METTL3 promoted tumor formation and proliferation in the in-situ xenograft model of NSCLC. The expression of LINC01006 was increased by METTL3 via m6A modification. c-MYC directly induced METTL3. Both c-MYC and LINC01006 were commonly targeted by miR-34a/b/c and miR-2682, and thereby c-MYC/METTL3/LINC01006 formed a positive feedback loop through miRNA targets in NSCLC.

CONCLUSIONS

LINC01006 is an oncogenic lncRNA, which induces migration, invasion and proliferation of NSCLC. METTL3 increases LINC01006 expression through stabilizing LINC01006 mRNA. c-MYC, as a transcription factor, activates METTL3, which results in an elevated level of LINC01006. c-MYC, METTL3 and LINC01006 form a positive feedback loop through multiple miRNA targets in NSCLC.

Signal recovery in single cell batch integration

Data integration to align cells across batches has become a cornerstone of single cell data analysis, critically affecting downstream results. Yet, how much biological signal is erased during integration? Currently, there are no guidelines for when the biological differences between samples are separable from batch effects, and thus, data integration usually involve a lot of guesswork: Cells across batches should be aligned to be "appropriately" mixed, while preserving "main cell type clusters". We show evidence that current paradigms for single cell data integration are unnecessarily aggressive, removing biologically meaningful variation. To remedy this, we present a novel statistical model and computationally scalable algorithm, CellANOVA, to recover biological signal that is lost during single cell data integration. CellANOVA utilizes a "pool-of-controls" design concept, applicable across diverse settings, to separate unwanted variation from biological variation of interest. When applied with existing integration methods, CellANOVA allows the recovery of subtle biological signals and corrects, to a large extent, the data distortion introduced by integration. Further, CellANOVA explicitly estimates cell- and gene-specific batch effect terms which can be used to identify the cell types and pathways exhibiting the largest batch variations, providing clarity as to which biological signals can be recovered. These concepts are illustrated on studies of diverse designs, where the biological signals that are recovered by CellANOVA are shown to be validated by orthogonal assays. In particular, we show that CellANOVA is effective in the challenging case of single-cell and single-nuclei data integration, where the recovered biological signals are replicated in an independent study.

Activation-induced deaminase expression defines mature B cell lymphoma in the mouse

Germinal centers (GCs) are the sites of secondary antibody diversification and underlie the mechanism of action of many vaccination strategies. Activation-induced deaminase (AID) triggers secondary antibody diversification through the introduction of somatic changes in immunoglobulin genes which lead to the generation of antibodies of higher affinity and more specialized effector functions. However, AID can also target other genomic regions, giving rise to mutations and chromosome translocations with oncogenic potential. Many human lymphomas originate from mature B cells that have undergone the GC reaction, such as the diffuse large B cell lymphoma, the follicular lymphoma and Burkitt lymphoma, and carry chromosome translocations. Mature B cell lymphomagenesis has been modeled in the mouse by the genetic introduction of chromosome translocations. Here, we present an in-depth characterization of one such model, λ-MYC mice. We found that young pre-tumor stage mice had a prominent block in early B cell differentiation that resulted in the generation of very aggressive tumors lacking surface B cell receptor (BCR) expression, indicating that a large fraction of tumors in λ-MYC mice arise from B cell precursors rather than from mature B cells. Further, we assessed the contribution of AID to B cell lymphomagenesis in λ-MYC mice by using a genetic tracer of historical AID expression. Only a fraction of tumors contained cells of GC origin as defined by AID expression. AID-experienced tumors associated with longer survival and resembled mature B cell lymphomas. Thus, AID expression defines Burkitt lymphomagenesis in λ-MYC mice.

The Myc Family and the Metastasis Suppressor NDRG1: Targeting Key Molecular Interactions with Innovative Therapeutics

Cancer is a leading cause of death worldwide, resulting in ∼10 million deaths in 2020. Major oncogenic effectors are the Myc proto-oncogene family, which consists of three members including c-Myc, N-Myc, and L-Myc. As a pertinent example of the role of the Myc family in tumorigenesis, amplification of MYCN in childhood neuroblastoma strongly correlates with poor patient prognosis. Complexes between Myc oncoproteins and their partners such as hypoxia-inducible factor-1α and Myc-associated protein X (MAX) result in proliferation arrest and pro-proliferative effects, respectively. Interactions with other proteins are also important for N-Myc activity. For instance, the enhancer of zest homolog 2 (EZH2) binds directly to N-Myc to stabilize it by acting as a competitor against the ubiquitin ligase, SCFFBXW7, which prevents proteasomal degradation. Heat shock protein 90 may also be involved in N-Myc stabilization since it binds to EZH2 and prevents its degradation. N-Myc downstream-regulated gene 1 (NDRG1) is downregulated by N-Myc and participates in the regulation of cellular proliferation via associating with other proteins, such as glycogen synthase kinase-3β and low-density lipoprotein receptor-related protein 6. These molecular interactions provide a better understanding of the biologic roles of N-Myc and NDRG1, which can be potentially used as therapeutic targets. In addition to directly targeting these proteins, disrupting their key interactions may also be a promising strategy for anti-cancer drug development. This review examines the interactions between the Myc proteins and other molecules, with a special focus on the relationship between N-Myc and NDRG1 and possible therapeutic interventions. SIGNIFICANCE STATEMENT: Neuroblastoma is one of the most common childhood solid tumors, with a dismal five-year survival rate. This problem makes it imperative to discover new and more effective therapeutics. The molecular interactions between major oncogenic drivers of the Myc family and other key proteins; for example, the metastasis suppressor, NDRG1, may potentially be used as targets for anti-neuroblastoma drug development. In addition to directly targeting these proteins, disrupting their key molecular interactions may also be promising for drug discovery.

MYC-targeted genes predict distant recurrence in patients with ocular adnexal extranodal marginal zone lymphoma

Ocular adnexal extranodal marginal zone lymphoma (OA-EMZL) is the most frequent subtype of ocular adnexal lymphoma, with a high propensity for recurrence. Distant recurrence (DR) as an essential prognostic event has unique clinical risk factors, but whether distinct molecular features exist remains poorly understood. Here, we identified potential biomarkers using proteomic analysis of 27 OA-EMZL samples. The MYC-targeted genes PCNA, MCM6, and MCM4 were identified as candidates. MYC-targeted genes were further identified as the most significantly activated gene set in patients with DR. The candidate genes were verified in samples from 11 patients with DR and 33 matched controls using immunohistochemistry. The 3-year and 5-year AUC values of MCM6 (0.699 and 0.757) were higher than those of Ki-67 (0.532 and 0.592). High expressions of MCM6 and MCM4 were significantly associated with shorter distant recurrence-free survival (Log-rank p = 0.017, Log-rank p = 0.0053). Multivariate Cox regression identified MCM6 expression as an independent risk factor for DR (HR, 6.86; 95% CI, 1.32-35.79; P = 0.02). Knockdown of c-Myc in B cells resulted in decreased MCM6 and MCM4 expression and reduced proliferative capacity. Our results suggest that activation of the MYC-targeted gene is a distinct molecular feature of DR in OA-EMZL. MYC-targeted gene, MCM6, is a promising pathological biomarker for DR.

In Silico, In Vitro, and In Vivo Investigations on Adapalene as Repurposed Third Generation Retinoid against Multiple Myeloma and Leukemia

The majority of hematopoietic cancers in adults are incurable and exhibit unpredictable remitting-relapsing patterns in response to various therapies. The proto-oncogene c-MYC has been associated with tumorigenesis, especially in hematological neoplasms. Therefore, targeting c-MYC is crucial to find effective, novel treatments for blood malignancies. To date, there are no clinically approved c-MYC inhibitors. In this study, we virtually screened 1578 Food and Drug Administration (FDA)-approved drugs from the ZINC15 database against c-MYC. The top 117 compounds from PyRx-based screening with the best binding affinities to c-MYC were subjected to molecular docking studies with AutoDock 4.2.6. Retinoids consist of synthetic and natural vitamin A derivatives. All-trans-retinoic acid (ATRA) were highly effective in hematological malignancies. In this study, adapalene, a third-generation retinoid usually used to treat acne vulgaris, was selected as a potent c-MYC inhibitor as it robustly bound to c-MYC with a lowest binding energy (LBE) of -7.27 kcal/mol, a predicted inhibition constant (pKi) of 4.69 µM, and a dissociation constant (Kd value) of 3.05 µM. Thus, we examined its impact on multiple myeloma (MM) cells in vitro and evaluated its efficiency in vivo using a xenograft tumor zebrafish model. We demonstrated that adapalene exerted substantial cytotoxicity against a panel of nine MM and two leukemic cell lines, with AMO1 cells being the most susceptible one (IC50 = 1.76 ± 0.39 µM) and, hence, the focus of this work. Adapalene (0.5 × IC50, 1 × IC50, 2 × IC50) decreased c-MYC expression and transcriptional activity in AMO1 cells in a dose-dependent manner. An examination of the cell cycle revealed that adapalene halted the cells in the G2/M phase and increased the portion of cells in the sub-G0/G1 phase after 48 and 72 h, indicating that cells failed to initiate mitosis, and consequently, cell death was triggered. Adapalene also increased the number of p-H3(Ser10) positive AMO1 cells, which is a further proof of its ability to prevent mitotic exit. Confocal imaging demonstrated that adapalene destroyed the tubulin network of U2OS cells stably transfected with a cDNA coding for α-tubulin-GFP, refraining the migration of malignant cells. Furthermore, adapalene induced DNA damage in AMO1 cells. It also induced apoptosis and autophagy, as demonstrated by flow cytometry and western blotting. Finally, adapalene impeded tumor growth in a xenograft tumor zebrafish model. In summary, the discovery of the vitamin A derivative adapalene as a c-MYC inhibitor reveals its potential as an avant-garde treatment for MM.

c-Myc protects hepatocellular carcinoma cell from ferroptosis induced by glutamine deprivation via upregulating GOT1 and Nrf2

BACKGROUND

Glutamine metabolism is critical for development of hepatocellular carcinoma (HCC), which makes it a novel promising treatment target. However, clinical evidence suggested glutamine withdrawal therapy does not achieved the desired tumor suppression. Therefore, it is valuable to investigate the survival mechanisms of tumors with glutamine deprivation.

METHODS

The HCC cells were cultured in glutamine-free medium or supplemented with glutamine metabolites or ferroptosis inhibitors. The parameters related to ferroptosis and the activity of GSH synthesis-related enzymes of the HCC cells were detected by corresponding kits. The expressions of glutamate oxaloacetate transaminase 1 (GOT1), c-Myc and Nrf2 were detected by western blot and qRT-PCR. The chromatin immunoprecipitation and luciferase reporter assays were performed to investigate the correlation between c-Myc and GOT1. The siRNAs of c-Myc and GOT1 were used to explore their roles in GSH (GSH) synthesis and ferroptosis in vitro and in vivo.

RESULTS

Glutamine deprivation-induced ferroptosis did not completely inhibit HCC cells proliferation. Glutamine deprivation activated the expression of c-Myc, which promoted the transcription of GOT1 and Nrf2, consequently maintaining the GSH synthesis and inhibiting ferroptosis. In addition, combined inhibition of GOT1 with glutamine deprivation could result in better inhibition of HCC in vitro and in vivo.

CONCLUSIONS

In our work, the results indicate that GOT1 induced by c-Myc may play an important role in combating ferroptosis due to glutamine deprivation, making it a significant target in glutamine withdrawal therapy. This study provides a theoretical foundation for the clinical targeted therapy for HCC.

Elevated nuclear PIGL disrupts the cMyc/BRD4 axis and improves PD-1 blockade therapy by dampening tumor immune evasion

To improve the efficacy of lenvatinib in combination with programmed death-1 (PD-1) blockade therapy for hepatocellular carcinoma (HCC), we screened the suppressive metabolic enzymes that sensitize HCC to lenvatinib and PD-1 blockade, thus impeding HCC progression. After analysis of the CRISPR‒Cas9 screen, phosphatidylinositol-glycan biosynthesis class L (PIGL) ranked first in the positive selection list. PIGL depletion had no effect on tumor cell growth in vitro but reprogrammed the tumor microenvironment (TME) in vivo to support tumor cell survival. Specifically, nuclear PIGL disrupted the interaction between cMyc/BRD4 on the distant promoter of target genes and thus decreased the expression of CCL2 and CCL20, which are involved in shaping the immunosuppressive TME by recruiting macrophages and regulatory T cells. PIGL phosphorylation at Y81 by FGFR2 abolished the interaction of PIGL with importin α/β1, thus retaining PIGL in the cytosol and facilitating tumor evasion by releasing CCL2 and CCL20. Clinically, elevated nuclear PIGL predicts a better prognosis for HCC patients and presents a positive correlation with CD8 + T-cell enrichment in tumors. Clinically, our findings highlight that the nuclear PIGL intensity or the change in PIGL-Y81 phosphorylation should be used as a biomarker to guide lenvatinib with PD-1 blockade therapy.

Removal of evolutionarily conserved functional MYC domains in a tilapia cell line using a vector-based CRISPR/Cas9 system

MYC transcription factors have critical roles in facilitating a variety of cellular functions that have been highly conserved among species during evolution. However, despite circumstantial evidence for an involvement of MYC in animal osmoregulation, mechanistic links between MYC function and osmoregulation are missing. Mozambique tilapia (Oreochromis mossambicus) represents an excellent model system to study these links because it is highly euryhaline and highly tolerant to osmotic (salinity) stress at both the whole organism and cellular levels of biological organization. Here, we utilize an O. mossambicus brain cell line and an optimized vector-based CRISPR/Cas9 system to functionally disrupt MYC in the tilapia genome and to establish causal links between MYC and cell functions, including cellular osmoregulation. A cell isolation and dilution strategy yielded polyclonal myca (a gene encoding MYC) knockout (ko) cell pools with low genetic variability and high gene editing efficiencies (as high as 98.2%). Subsequent isolation and dilution of cells from these pools produced a myca ko cell line harboring a 1-bp deletion that caused a frameshift mutation. This frameshift functionally inactivated the transcriptional regulatory and DNA-binding domains predicted by bioinformatics and structural analyses. Both the polyclonal and monoclonal myca ko cell lines were viable, propagated well in standard medium, and differed from wild-type cells in morphology. As such, they represent a new tool for causally linking myca to cellular osmoregulation and other cell functions.