The critical role of AMPK in driving Akt activation under stress, tumorigenesis and drug resistance

Can vildagliptin protect against radiation-induced premature ovarian failure? Insights into the AMPK and AKT signaling pathways

BACKGROUND

Among the detrimental side effects caused by radiotherapy in young females is the ovarian damage, eventually causing premature ovarian failure (POF). While many signaling pathways contribute to the pathogenesis of POF, to date no sufficient data exist on the AMPK and AKT signaling pathways in irradiated ovaries. Both AMPK and AKT play crucial roles in the process of folliculogenesis. Vildagliptin (vilda) is a dipeptidyl peptidase-4 inhibitor with modulatory effect on both AMPK and AKT. Therefore, our study aimed to investigate the biochemical changes that occur in the AMPK/AKT signaling pathway, and the effect of co-administration of vildagliptin in radiation-induced POF.

METHODS

Female Sprague-dawley rats were randomly divided into four groups: control, radiation, radiation + vilda, or vilda alone groups. Vilda was administered orally once/day, and on the 10th day of the experiment, radiation and radiation + vilda group rats were subjected to 3.2 Gy of whole-body gamma irradiation. Behavioral activity was assessed on the 13th day of the experiment. On day 14 of the experiment, all rats were euthanized. Serum samples were collected, and ovaries were dissected for histological and biochemical analyses.

RESULTS

Irradiation of female rats resulted in increased locomotor hyperactivity, impaired memory, and ovarian damage as evidenced by the marked histopathological deterioration. Additionally, irradiation led to a significant decrease in body weight gain, gonadosomatic index, and serum estradiol level. Further, it caused a significant increase in serum AMH, phosphorylated AMPK, phosphorylated AKT, cytoplasmic Nrf2 expression and phosphorylated CREB levels. Co-administration of vilda exhibited neuroprotective effects, preserved the ovarian histological architecture but failed to preserve the primordial follicle pool in irradiated rats.

CONCLUSION

In conclusion, AMPK/AKT signaling pathway is upregulated in radiation-induced POF. It possibly contributes to POF pathogenesis by accelerating the activation of primordial follicles, hence leading to their premature depletion. Coadministration of vilda can protect the ovaries and temporarily preserve its endocrine function; however, it does not sustain the ovarian reproductive capacity due to the early depletion of the pool of primordial follicles. Women undergoing radiotherapy should be cautious with the use of AKT-activating drugs.

Long-Term Administration of Antioxidant N-Acetyl-L-Cysteine Impacts Beta Cell Oxidative Stress, Insulin Secretion, and Intracellular Signaling Pathways in Aging Mice

Research into the effects of long-term antioxidant supplementation on the islet microenvironment is limited. This study examined whether long-term N-acetyl-L-cysteine (NAC) supplementation can prevent changes in metabolic outcomes, beta cell function, and pancreatic stellate cell (PaSC) activation in aging mice. Male C57BL/6N mice at 18 weeks were administered 50 mM NAC through their daily drinking water and treated for up to 60 weeks. Aging NAC mice displayed lower body weights and improved glucose tolerance but reduced insulin secretion and insulin signaling compared to control (ND) mice. When some 40-week-old ND and NAC mice were subjected to 8 weeks of a high-fat diet (HFD)-stress challenge, results showed that NAC reduced HFD-induced beta cell oxidative stress and preserved nuclear PDX-1 expression. The findings from this study suggest that while NAC can be beneficial for diet-induced stress during aging, the effects of long-term NAC on the islets of physiologically aging mice are more ambiguous. Further exploration is required to determine the effects of NAC-mediated lowering of beta cell oxidative stress on insulin secretion and signaling pathways. This study highlights the importance of investigating oxidative stress balance in aging islets under normal diet conditions to determine if antioxidative therapies can be utilized without interfering with essential physiological processes.

Polysaccharide from Momordica charantia L. Alleviates Type 2 Diabetes Mellitus in Mice by Activating the IRS1/PI3K/Akt and AMPK Signaling Pathways and Regulating the Gut Microbiota

Developing effective therapies for type 2 diabetes mellitus (T2DM) remains a critical global health priority. This study explored the novel antidiabetic potential of MCPS-3, a polysaccharide derived from Momordica charantia L., and its underlying mechanisms in a high-fat diet and streptozotocin-induced T2DM mouse model. Our results indicated that MCPS-3 treatment significantly reduced serum glucose levels, improved glucose tolerance, and enhanced insulin sensitivity, alongside increased glycogen storage and improved liver enzyme activities. It also alleviated diabetes-induced damage in the pancreas, liver, and kidneys and improved serum lipid profiles by lowering triglycerides and LDL-C while increasing HDL-C levels. Mechanistic studies revealed that MCPS-3 activated the IRS1/PI3K/AKT and AMPK pathways, essential for glucose and lipid regulation. Importantly, MCPS-3 treatment restored gut microbial balance by increasing microbial diversity and shifting the composition of harmful and beneficial bacteria. Metabolomic analysis further identified changes in 46 metabolites, implicating pathways related to steroid and lipid metabolism. These findings underscore the multifaceted nature of MCPS-3's antidiabetic effects, including its role as a modulator of gut microbiota and metabolic pathways, and support its potential as a therapeutic agent for improving metabolic health in T2DM.

Therapeutic assessment of a novel mitochondrial complex I inhibitor in in vitro and in vivo models of Alzheimer's disease

Despite recent approval of monoclonal antibodies that reduce amyloid (Aβ) accumulation, the development of disease-modifying strategies targeting the underlying mechanisms of Alzheimer's disease (AD) is urgently needed. We demonstrate that mitochondrial complex I (mtCI) represents a druggable target, where its weak inhibition activates neuroprotective signaling, benefiting AD mouse models with Aβ and p-Tau pathologies. Rational design and structure-activity relationship studies yielded novel mtCI inhibitors profiled in a drug discovery funnel designed to address their safety, selectivity, and efficacy. The new lead compound C458 is highly protective against Aβ toxicity, has favorable pharmacokinetics, and has minimal off-target effects. C458 exhibited excellent brain penetrance, activating neuroprotective pathways with a single dose. Preclinical studies in APP/PS1 mice were conducted via functional tests, metabolic assessment, in vivo 31P-NMR spectroscopy, blood cytokine panels, ex vivo electrophysiology, and Western blotting. Chronic oral administration improved long-term potentiation, reduced oxidative stress and inflammation, and enhanced mitochondrial biogenesis, antioxidant signaling, and cellular energetics. These studies provide further evidence that the restoration of mitochondrial function and brain energetics in response to mild energetic stress represents a promising disease-modifying strategy for AD.

Shared molecular, cellular, and environmental hallmarks in cardiovascular disease and cancer: Any place for drug repurposing?

Cancer and cardiovascular disease (CVD) are the 2 biggest killers worldwide. Specific treatments have been developed for the 2 diseases. However, mutual therapeutic targets should be considered because of the overlap of cellular and molecular mechanisms. Cancer research has grown at a fast pace, leading to an increasing number of new mechanistic treatments. Some of these drugs could prove useful for treating CVD, which realizes the concept of cancer drug repurposing. This review provides a comprehensive outline of the shared hallmarks of cancer and CVD, primarily ischemic heart disease and heart failure. We focus on chronic inflammation, altered immune response, stromal and vascular cell activation, and underlying signaling pathways causing pathological tissue remodeling. There is an obvious scope for targeting those shared mechanisms, thereby achieving reciprocal preventive and therapeutic benefits. Major attention is devoted to illustrating the logic, advantages, challenges, and viable examples of drug repurposing and discussing the potential influence of sex, gender, age, and ethnicity in realizing this approach. Artificial intelligence will help to refine the personalized application of drug repurposing for patients with CVD. SIGNIFICANCE STATEMENT: Cancer and cardiovascular disease (CVD), the 2 biggest killers worldwide, share several underlying cellular and molecular mechanisms. So far, specific therapies have been developed to tackle the 2 diseases. However, the development of new cardiovascular drugs has been slow compared with cancer drugs. Understanding the intersection between pathological mechanisms of the 2 diseases provides the basis for repurposing cancer therapeutics for CVD treatment. This approach could allow the rapid development of new drugs for patients with CVDs.

Fructose induces inflammatory activation in macrophages and microglia through the nutrient-sensing ghrelin receptor

High fructose corn syrup (HFCS) is a commonly used sweetener in soft drinks and processed foods, and HFCS exacerbates inflammation when consumed in excess. Fructose, a primary component of HFCS; however, it is unclear whether fructose directly activates inflammatory signaling. Growth hormone secretagogue receptor (GHSR) is a receptor of the nutrient-sensing hormone ghrelin. We previously reported that GHSR ablation mitigates HFCS-induced inflammation in adipose tissue and liver, shifting macrophages toward an anti-inflammatory spectrum. Since inflammation is primarily governed by innate immune cells, such as macrophages in the peripheral tissues and microglia in the brain, this study aims to investigate whether GHSR autonomously regulates pro-inflammatory activation in macrophages and microglia upon fructose exposure. GHSR deletion mutants of RAW 264.7 macrophages and the immortalized microglial cell line (IMG) were generated using CRISPR-Cas9 gene editing. After treating the cells with equimolar concentrations of fructose or glucose for 24 h, fructose increased mRNA and protein expression of GHSR and pro-inflammatory cytokines (Il1β, Il6, and Tnfα) in both macrophages and microglia, suggesting that fructose activates Ghsr and induces inflammation directly in macrophages and microglia. Remarkably, GHSR deletion mutants (Ghsrmutant) of macrophages and microglia exhibited reduced inflammatory responses to fructose, indicating that GHSR mediates fructose-induced inflammation. Furthermore, we found that GHSR regulates fructose transport and fructose metabolism and mediates fructose-induced inflammatory activation through CREB-AKT-NF-κB and p38 MAPK signaling pathways. Our results underscore that fructose triggers inflammation, and reducing HFCS consumption would reduce disease risk. Moreover, these findings reveal for the first time that the nutrient-sensing receptor GHSR plays a crucial role in fructose-mediated inflammatory activation, suggesting that targeting GHSR may be a promising therapeutic approach to combat the immunotoxicity of foods that contain fructose.

α-arbutin prevents UVA-induced skin photodamage via alleviating DNA damage and collagen degradation in NIH-3T3 cells

Ultraviolet radiation (UV) causes certain side effects to the skin, and their accumulation to a certain extent can lead to accelerated aging of the skin. Recent studies suggest that α-arbutin may be useful in various disorders such as hyperpigmentation disorders, wound healing, and antioxidant activity. However, the role of α-arbutin in skin photodamage is unclear. In this study, under UVA-induced photodamage conditions, α-arbutin treated mouse skin fibroblasts (NIH-3T3) can repair DNA damage and resist apoptosis by reducing the production of reactive oxygen species (ROS) and increasing the phosphorylation of glycogen synthase kinase 3 beta (GSK3β) to orchestra AKT/GSK3β pathway. Meanwhile, α-arbutin can also regulate collagen metabolism and facilitate the replenishment of collagen by targeting the phosphorylation of SMAD3 to mediate the TGFβ/SMAD pathway in NIH-3T3. In conclusion, we found that α-arbutin can mitigate the detrimental effects of skin photodamage induced by UVA irradiation, and provides a theoretical basis for the use of α-arbutin in the treatment of skin photodamage.

Mitigating ibrutinib-induced ventricular arrhythmia and cardiac dysfunction with metformin

BACKGROUND

Ibrutinib is a first-line drug that targets Bruton's tyrosine kinase for the treatment of B cell cancer. However, cardiotoxicity induced by ibrutinib is a major side effect that limits its clinical use. This study aimed to investigate the mechanism of ibrutinib-induced cardiotoxicity and evaluate the protective role of metformin.

METHODS

The study utilized male C57BL/6 J mice, which were administered ibrutinib at a dosage of 30 mg/kg/day via oral gavage for 4 weeks to induce cardiotoxicity. Metformin was administered orally at 200 mg/kg/day for 5 weeks, starting 1 week before ibrutinib treatment. Cardiac function was assessed using echocardiography and electrophysiological studies, including surface electrocardiography and epicardial electrical mapping. Blood pressure was measured using a tail-cuff system. Western blot analysis was conducted to evaluate the activity of the PI3K-AKT and AMPK pathways, along with apoptosis markers.

RESULTS

C57BL/6 J mice were treated with ibrutinib for 4 weeks to assess its effect on cardiac function. We observed that ibrutinib induced ventricular arrhythmia and abnormal conduction while reducing the left ventricular ejection fraction. Furthermore, pretreatment with metformin reversed ibrutinib-induced cardiotoxicity. Mechanistically, ibrutinib decreased PI3K-AKT activity, resulting in apoptosis of cardiomyocytes. Administration of metformin upregulated AMPK and PI3K-AKT activity, which contributed to the improvement of cardiac function.

CONCLUSION

The study concludes that metformin effectively mitigates ibrutinib-induced cardiotoxicity, including ventricular arrhythmia and cardiac dysfunction, by enhancing AMPK and PI3K-AKT pathway activity. These findings suggest that metformin holds potential as a therapeutic strategy to protect against the adverse cardiac effects associated with ibrutinib treatment, offering a promising approach for improving the cardiovascular safety of patients undergoing therapy for B cell cancers.

Rat Sarcoma Virus Family Genes in Acute Myeloid Leukemia: Pathogenetic and Clinical Implications

Acute myeloid leukemias (AMLs) comprise a group of genetically heterogeneous hematological malignancies that result in the abnormal growth of leukemic cells and halt the maturation process of normal hematopoietic stem cells. Despite using molecular and cytogenetic risk classification to guide treatment decisions, most AML patients survive for less than five years. A deeper comprehension of the disease's biology and the use of new, targeted therapy approaches could potentially increase cure rates. RAS oncogene mutations are common in AML patients, being observed in about 15-20% of AML cases. Despite extensive efforts to find targeted therapy for RAS-mutated AMLs, no effective and tolerable RAS inhibitor has received approval for use against AMLs. The frequency of RAS mutations increases in the context of AMLs' chemoresistance; thus, novel anti-RAS strategies to overcome drug resistance and improve patients' therapy responses and overall survival are the need of the hour. In this article, we aim to update the current knowledge on the role of RAS mutations and anti-RAS strategies in AML treatments.

Molecular Basis of Oncogenic PI3K Proteins

The dysregulation of phosphatidylinositol 3-kinase (PI3K) signaling plays a pivotal role in driving neoplastic transformation by promoting uncontrolled cell survival and proliferation. This oncogenic activity is primarily caused by mutations that are frequently found in PI3K genes and constitutively activate the PI3K signaling pathway. However, tumorigenesis can also arise from nonmutated PI3K proteins adopting unique active conformations, further complicating the understanding of PI3K-driven cancers. Recent structural studies have illuminated the functional divergence among highly homologous PI3K proteins, revealing how subtle structural alterations significantly impact their activity and contribute to tumorigenesis. In this review, we summarize current knowledge of Class I PI3K proteins and aim to unravel the complex mechanism underlying their oncogenic traits. These insights will not only enhance our understanding of PI3K-mediated oncogenesis but also pave the way for the design of novel PI3K-based therapies to combat cancers driven by this signaling pathway.

LKB1 dictates sensitivity to immunotherapy through Skp2-mediated ubiquitination of PD-L1 protein in non-small cell lung cancer

BACKGROUND

Loss-of-function mutations of liver kinase B (LKB1, also termed as STK11 (serine/threonine kinase 11)) are frequently detected in patients with non-small cell lung cancer (NSCLC). The LKB1 mutant NSCLC was refractory to almost all the antitumor treatments, including programmed cell death protein 1 (PD-1)/programmed death-ligand 1 (PD-L1) blockade therapy. Unfortunately, mechanisms underlying resistance to immunotherapy are not fully understood. In this study, we deciphered how LKB1 regulated sensitivity to anti-PD-1/PD-L1 immunotherapy.

METHODS

We investigated the mutational landscape of LKB1 mutant NSCLC in next generation sequencing (NGS) data sets. Expression of LKB1, PD-L1 and S-phase kinase-associated protein 2 (Skp2) in NSCLC samples were assessed by immunohistochemistry (IHC). The tumor microenvironment (TME) profiling of LKB1 wild type (WT) and mutant NSCLC was performed using fluorescent multiplex IHC. Mass spectrometry and enrichment analysis were used to identify LKB1 interacting proteins. Mechanistic pathways were explored by immunoblotting, ubiquitination assay, cycloheximide chase assay and immunoprecipitation assay.

RESULTS

By using NGS data sets and histological approaches, we demonstrated that LKB1 status was positively associated with PD-L1 protein expression and conferred a T cell-enriched "hot" TME in NSCLC. Patients with good responses to anti-PD-1/PD-L1 immunotherapy possessed a high level of LKB1 and PD-L1. Skp2 emerged as the molecular hub connecting LKB1 and PD-L1, by which Skp2 catalyzed K63-linked polyubiquitination on K136 and K280 residues to stabilize PD-L1 protein. Inhibition of Skp2 expression by short hairpin RNA or its E3 ligase activity by compound #25 abrogated intact expression of PD-L1 in vitro and generated a T cell-excluded "cold" TME in vivo. Thus, the LKB1-Skp2-PD-L1 regulatory loop was crucial for retaining PD-L1 protein expression and manipulation of this pathway would be a feasible approach for TME remodeling.

CONCLUSION

LKB1 and Skp2 are required for intact PD-L1 protein expression and TME remodeling in NSCLC. Inhibition of Skp2 resulted in a conversion from "hot" TME to "cold" TME and abrogated therapeutic outcomes of immunotherapy. Screening LKB1 and Skp2 status would be helpful to select recipients who may benefit from anti-PD-1/PD-L1 immunotherapy.

pERK transition-induced directional mode switching promotes epithelial tumor cell migration

Increasing evidence suggests that tumor cells exhibit extreme plasticity in migration modes in order to adapt to microenvironments. However, the underlying mechanism for governing the migration mode switching is still unclear. Here, we revealed that epithelial tumor cells could develop a stable directional mode driven by hyperactivated ERK activity. This highly activated and dynamically changing ERK activity, called pERK transition, is crucial for inducing the switch from pauses state to directional movement and is also necessary for maintaining epithelial tumor cells in the directional mode. PERK transition integrated pERK surf, the dynamic and localized ERK activity at the leading edge. The sequential activation of RhoA and Rac1 by pERK transition played critical roles in generation of pERK surf activity through a movement feedback mechanism. PERK transition activity converted the orderly collective migration into the disordered dispersal movement, enhanced the invasiveness of epithelial tumor cells, and promoted their metastasis in immune-deficient mice. These findings revealed that the exquisite spatiotemporal organization of ERK activity orchestrates migration and invasion of tumor cells and provide evidence for the mechanism underlying migration mode switching in epithelial tumor cells.

A novel microRNA promotes coxsackievirus B4 infection of pancreatic β cells

The epidemiological association of coxsackievirus B infection with type 1 diabetes suggests that therapeutic strategies that reduce viral load could delay or prevent disease onset. Moreover, recent studies suggest that treatment with antiviral agents against coxsackievirus B may help preserve insulin levels in type 1 diabetic patients. In the current study, we performed small RNA-sequencing to show that infection of immortalized trophoblast cells with coxsackievirus caused differential regulation of several miRNAs. One of these, hsa-miR-AMC1, was similarly upregulated in human pancreatic β cells infected with coxsackievirus B4. Moreover, treatment of β cells with non-cytotoxic concentrations of an antagomir that targets hsa-miR-AMC1 led to decreased CVB4 infection, suggesting a positive feedback loop wherein this microRNA further promotes viral infection. Interestingly, some predicted target genes of hsa-miR-AMC1 are shared with hsa-miR-184, a microRNA that is known to suppress genes that regulate insulin production in pancreatic β cells. Consistently, treatment of coxsackievirus B4-infected β cells with the hsa-miR-AMC1 antagomir was associated with a trend toward increased insulin production. Taken together, our findings implicate novel hsa-miR-AMC1 as a potential early biomarker of coxsackievirus B4-induced type 1 diabetes and suggest that inhibiting hsa-miR-AMC1 may provide therapeutic benefit to type 1 diabetes patients. Our findings also support the use of trophoblast cells as a model for identifying microRNAs that might be useful diagnostic markers or therapeutic targets for coxsackievirus B-induced type 1 diabetes.

Macropinocytosis mediates resistance to loss of glutamine transport in triple-negative breast cancer

Triple-negative breast cancer (TNBC) metabolism and cell growth uniquely rely on glutamine uptake by the transporter ASCT2. Despite previous data reporting cell growth inhibition after ASCT2 knockdown, we here show that ASCT2 CRISPR knockout is tolerated by TNBC cell lines. Despite the loss of a glutamine transporter and low rate of glutamine uptake, intracellular glutamine steady-state levels were increased in ASCT2 knockout compared to control cells. Proteomics analysis revealed upregulation of macropinocytosis, reduction in glutamine efflux and increased glutamine synthesis in ASCT2 knockout cells. Deletion of ASCT2 in the TNBC cell line HCC1806 induced a strong increase in macropinocytosis across five ASCT2 knockout clones, compared to a modest increase in ASCT2 knockdown. In contrast, ASCT2 knockout impaired cell proliferation in the non-macropinocytic HCC1569 breast cancer cells. These data identify macropinocytosis as a critical secondary glutamine acquisition pathway in TNBC and a novel resistance mechanism to strategies targeting glutamine uptake alone. Despite this adaptation, TNBC cells continue to rely on glutamine metabolism for their growth, providing a rationale for targeting of more downstream glutamine metabolism components.

HNF1ɑ promotes colorectal cancer progression via HKDC1-mediated activation of AKT/AMPK signaling pathway

The hepatocyte nuclear factor-1 (HNF1ɑ) is a transcription factor that contributes to several kinds of cancer progression. However, very little is known regarding the mechanisms underlying the activity of HNF1ɑ. We aimed to explore the role of HNF1ɑ in the progress of colorectal cancer (CRC) and elucidate its molecular mechanism. HNF1ɑ expression was upregulated in CRC samples and high expression of HNF1ɑ was associated with poor prognosis of CRC patients. HNF1α knockdown and overexpression inhibited and promoted proliferation, migration and invasion of CRC cells both in vitro and in vivo respectively. Mechanistically, HNF1ɑ increased the transcriptional activity of hexokinase domain component 1（HKDC1）promoter, thus activated AKT/AMPK signaling. Meanwhile, HKDC1 upregulation was important for the proliferation, migration and invasion of CRC cells and knockdown of HKDC1 significantly reversed the proliferation, migration and invasion induced by HNF1α overexpression. Taken together, HNF1ɑ contributes to CRC progression and metastasis through binding to HKDC1 and activating AKT/AMPK signaling. Targeting HNF1ɑ could be a potential therapeutic strategy for CRC patients.

New developments in AMPK and mTORC1 cross-talk

Metabolic homeostasis and the ability to link energy supply to demand are essential requirements for all living cells to grow and proliferate. Key to metabolic homeostasis in all eukaryotes are AMPK and mTORC1, two kinases that sense nutrient levels and function as counteracting regulators of catabolism (AMPK) and anabolism (mTORC1) to control cell survival, growth and proliferation. Discoveries beginning in the early 2000s revealed that AMPK and mTORC1 communicate, or cross-talk, through direct and indirect phosphorylation events to regulate the activities of each other and their shared protein substrate ULK1, the master initiator of autophagy, thereby allowing cellular metabolism to rapidly adapt to energy and nutritional state. More recent reports describe divergent mechanisms of AMPK/mTORC1 cross-talk and the elaborate means by which AMPK and mTORC1 are activated at the lysosome. Here, we provide a comprehensive overview of current understanding in this exciting area and comment on new evidence showing mTORC1 feedback extends to the level of the AMPK isoform, which is particularly pertinent for some cancers where specific AMPK isoforms are implicated in disease pathogenesis.

Discovery of Novel [1,2,4]Triazolo[1,5-a]pyrimidine Derivatives as Novel Potent S-Phase Kinase-Associated Protein 2 (SKP2) Inhibitors for the Treatment of Cancer

Skp1-CUL1-ROC1-F-box E3 ubiquitin ligases' main component S-phase kinase-associated protein 2 (Skp2) is responsible for specifically recognizing ubiquitination-modified substrates to be degraded such as p27 and p21 in the case of binding with adaptor protein Cks1. Pharmacological inhibition of Skp2 has exhibited promising antitumor activity. Herein, we present the design and optimization of a series of [1,2,4]triazolo[1,5-a]pyrimidine-based small molecules targeting Skp2. Among them, E35 demonstrated excellent inhibitory activities against the binding of Skp2-Cks1. In addition, compound E35 significantly inhibited colony formation and migration, as well as arrested the cell cycle at the S-phase. Mechanistically, compound E35 markedly decreased the expression of Skp2, as well as increased the expression of its substrates p21 and p27. Furthermore, compound E35 showed an obvious inhibitory effect on MGC-803 xenograft mice without obvious toxicity. All of these results suggest that compound E35 might be a valuable lead compound for antitumor agents targeting Skp2.

EDIL3 alleviates Mannan-induced psoriatic arthritis by slowing the intracellular glycolysis process in mononuclear-derived dendritic cells

Psoriatic arthritis (PsA) is an immune-mediated, chronic inflammatory joint disease that commonly occurs as a complication of psoriasis. EGF-like repeats and discoidal I-like domain 3 (EDIL3) is a secreted protein with multiple structural domains and associated with various physiological functions. In this study, we employed a mannan-induced psoriatic arthritis model to investigate the impact of EDIL3 on PsA pathogenesis. Notably, a downregulation of EDIL3 expression was observed in the PsA model, which correlated with increased disease severity. EDIL3 knockout mice exhibited a more severe phenotype of PsA, which was ameliorated upon re-infusion of recombinant EDIL3 protein. The mitigation effect of EDIL3 on PsA depends on its regulation of the activation of monocyte-derived DCs (MoDCs) and T-help 17 cells (Th17). After inhibiting the function of MoDCs and Th17 cells with neutralizing antibodies, the beneficial effects of EDIL3 on PsA were lost. By inducing adenosine monophosphate (AMP)-activated protein kinase (AMPK) phosphorylation and suppressing protein kinase B (AKT) phosphorylation, EDIL3 attenuates intracellular glycolysis in MoDCs stimulated by glucose, thereby impeding their maturation and differentiation. Moreover, it diminishes the differentiation of Th17 cells and decelerates the progression of PsA. In conclusion, our findings elucidate the role and mechanism of EDIL3 in the development of PsA, providing a new target for clinical diagnosis and treatment.

AMPK Activation Serves as a Common Pro-Survival Pathway in Esophageal Adenocarcinoma Cells

Esophageal adenocarcinoma (EAC) is a subtype of esophageal cancer that is difficult to treat, with overall poor survival and frequent recurrence despite curative-intent treatment strategies. There is limited understanding of EAC resistance mechanisms to chemotherapy or radiation. We have found that the AMP-activated protein kinase (AMPK) can serve a pro-survival function in EAC cells in response to cytotoxic treatments. Treatment with the IL-6 inhibitor tocilizumab, which previously has been shown to inhibit EAC organoid growth, resulted in the activation of AMPK in the OE33 EAC cell line, which was accompanied by a decrease in MTORC1 signaling and an increase in oxidative mitochondrial metabolism, both known downstream effects of AMPK activation to promote cell survival under conditions of metabolic stress. This increase in oxidative metabolism was abrogated in cells with a genetic knockdown of AMPK expression. Furthermore, we found that AMPK was activated in OE33 cells following treatment with cisplatin or ionizing radiation. Treatment with the AMPK inhibitor Compound C or genetic knockdown of AMPK expression enhanced cell death in a synergistic manner with chemotherapeutics or ionizing radiation. These findings were recapitulated in human patient-derived EAC organoids, suggesting that AMPK may be a common pro-survival mechanism to confer treatment resistance in EAC and may serve as a novel target to enhance the efficacy of current and future treatment strategies.

Phytochemicals regulate cancer metabolism through modulation of the AMPK/PGC-1α signaling pathway

BACKGROUND

Due to the complex pathophysiological mechanisms involved in cancer progression and metastasis, current therapeutic approaches lack efficacy and have significant adverse effects. Therefore, it is essential to establish novel strategies for combating cancer. Phytochemicals, which possess multiple biological activities, such as antioxidant, anti-inflammatory, antimutagenic, immunomodulatory, antiproliferative, anti-angiogenesis, and antimetastatic properties, can regulate cancer progression and interfere in various stages of cancer development by suppressing various signaling pathways.

METHODS

The current systematic and comprehensive review was conducted based on Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) criteria, using electronic databases, including PubMed, Scopus, and Science Direct, until the end of December 2023. After excluding unrelated articles, 111 related articles were included in this systematic review.

RESULTS

In this current review, the major signaling pathways of cancer metabolism are highlighted with the promising anticancer role of phytochemicals. This was through their ability to regulate the AMP-activated protein kinase (AMPK)/peroxisome proliferator-activated receptor-gamma coactivator-1α (PGC-1α) signaling pathway. The AMPK/PGC-1α signaling pathway plays a crucial role in cancer cell metabolism via targeting energy homeostasis and mitochondria biogenesis, glucose oxidation, and fatty acid oxidation, thereby generating ATP for cell growth. As a result, targeting this signaling pathway may represent a novel approach to cancer treatment. Accordingly, alkaloids, phenolic compounds, terpene/terpenoids, and miscellaneous phytochemicals have been introduced as promising anticancer agents by regulating the AMPK/PGC-1α signaling pathway. Novel delivery systems of phytochemicals targeting the AMPK/PGC-1α pathway in combating cancer are also highlighted in this review.

SIRT7 knockdown promotes gemcitabine sensitivity of pancreatic cancer cell via upregulation of GLUT3 expression

Gemcitabine serves as a first-line chemotherapeutic treatment for pancreatic cancer (PC), but it is prone to rapid drug resistance. Increasing the sensitivity of PC to gemcitabine has long been a focus of research. Fasting interventions may augment the effects of chemotherapy and present new options. SIRT7 is known to link metabolism with various cellular processes through post-translational modifications. We found upregulation of SIRT7 in PC cells is associated with poor prognosis and gemcitabine resistance. Cross-analysis of RNA-seq and ATAC-seq data suggested that GLUT3 might be a downstream target gene of SIRT7. Subsequent investigations demonstrated that SIRT7 directly interacts with the enhancer region of GLUT3 to desuccinylate H3K122. Our group's another study revealed that GLUT3 can transport gemcitabine in breast cancer cells. Here, we found GLUT3 KD reduces the sensitivity of PC cells to gemcitabine, and SIRT7 KD-associated gemcitabine-sensitizing could be reversed by GLUT3 KD. While fasting mimicking induced upregulation of SIRT7 expression in PC cells, knocking down SIRT7 enhanced sensitivity to gemcitabine through upregulating GLUT3 expression. We further confirmed the effect of SIRT7 deficiency on the sensitivity of gemcitabine under fasting conditions using a mouse xenograft model. In summary, our study demonstrates that SIRT7 can regulate GLUT3 expression by binding to its enhancer and altering H3K122 succinylation levels, thus affecting gemcitabine sensitivity in PC cells. Additionally, combining SIRT7 knockdown with fasting may improve the efficacy of gemcitabine. This unveils a novel mechanism by which SIRT7 influences gemcitabine sensitivity in PC and offer innovative strategies for clinical combination therapy with gemcitabine.

The interaction between 20-hydroxyecdysone and AMPK through PI3K activation in Chinese mitten crab, Eriocheir sinensis

In crustaceans, the steroid hormone 20-hydroxyecdysone (20E) initiates molting, and the molting process is also regulated by energy metabolism. AMPK is an energy sensor and plays a critical role in systemic energy balance. Here, the regulatory mechanism in the interaction between 20E and AMPK was investigated in Chinese mitten crab, Eriocheir sinensis. The results showed that the 20E concentration and the mRNA expression levels of 20E receptors in hepatopancreas were down-regulated post AMPK activator (AICAR) treatment, and were up-regulated after AMPK inhibitor (Compound C) injection in crabs. Besides, the molt-inhibiting hormone (MIH) gene expression in eyestalk showed the opposite patterns in response to the AICAR and Compound C treatment, respectively. Further investigation found that there was a significant reduction in 20E concentration post PI3K inhibitor (LY294002) treatment, and the phosphorylation level of PI3K was increased in hepatopancreas after AMPK inhibitor injection. On the other hand, the positive regulation of PI3K-mediated activation of AMPK was also observed, the phosphorylation levels of AMPKα, AMPKβ and PI3K in hepatopancreas were significantly increased post 20E injection. In addition, the phosphorylation levels of AMPKα and AMPKβ induced by 20E were decreased after the injection of PI3K inhibitor. Taken together, these results suggest that the regulatory cross-talk between 20E and AMPK is likely to act through PI3K pathway in E. sinensis, which appeared to be helpful for a better understanding in molting regulation.

Digirseophene A promotes recovery in injured developing cerebellum via AMPK/AKT/GSK3β pathway-mediated neural stem cell proliferation

Neural stem cells (NSCs) exhibit a remarkable capacity for self-renewal and have the potential to differentiate into various neural lineage cells, which makes them pivotal in the management of neurological disorders. Harnessing the inherent potential of endogenous NSCs for enhancing nerve repair and regeneration represents an optimal approach to addressing diseases of the nervous system. In this study, we explored the potential of a novel benzophenone derivative named Digirseophene A (DGA), which was isolated from the endophytic fungus Corydalis tomentella. Previous experiments have extensively identified and characterized DGA, revealing its unique properties. Our findings demonstrate the remarkable capability of DGA to stimulate neural stem cell proliferation, both in vitro and in vivo. Furthermore, we established a model of radiation-induced cerebellar injury to assess the effects of DGA on the distribution of different cell subpopulations within the damaged cerebellum, thereby suggesting its beneficial role in cerebellar repair. In addition, our observations on a primary NSCs model revealed that DGA significantly increased cellular oxygen consumption, indicating increased energy and metabolic demands. By utilizing various pathway inhibitors in combination with DGA, we successfully demonstrated its ability to counteract the suppressive impacts of AMPK and GSK3β inhibitors on NSC proliferation. Collectively, our research results strongly suggest that DGA, as an innovative compound, exerts its role in activating NSCs and promoting injury repair through the regulation of the AMPK/AKT/GSK3β pathway.

Hallmarks of cancer resistance

This review explores the hallmarks of cancer resistance, including drug efflux mediated by ATP-binding cassette (ABC) transporters, metabolic reprogramming characterized by the Warburg effect, and the dynamic interplay between cancer cells and mitochondria. The role of cancer stem cells (CSCs) in treatment resistance and the regulatory influence of non-coding RNAs, such as long non-coding RNAs (lncRNAs), microRNAs (miRNAs), and circular RNAs (circRNAs), are studied. The chapter emphasizes future directions, encompassing advancements in immunotherapy, strategies to counter adaptive resistance, integration of artificial intelligence for predictive modeling, and the identification of biomarkers for personalized treatment. The comprehensive exploration of these hallmarks provides a foundation for innovative therapeutic approaches, aiming to navigate the complex landscape of cancer resistance and enhance patient outcomes.

Potential mechanisms of cancer prevention and treatment by sulforaphane, a natural small molecule compound of plant-derived

Despite recent advances in tumor diagnosis and treatment technologies, the number of cancer cases and deaths worldwide continues to increase yearly, creating an urgent need to find new methods to prevent or treat cancer. Sulforaphane (SFN), as a member of the isothiocyanates (ITCs) family, which is the hydrolysis product of glucosinolates (GLs), has been shown to have significant preventive and therapeutic cancer effects in different human cancers. Early studies have shown that SFN scavenges oxygen radicals by increasing cellular defenses against oxidative damage, mainly through the induction of phase II detoxification enzymes by nuclear factor erythroid 2-related factor 2 (Nrf2). More and more studies have shown that the anticancer mechanism of SFN also includes induction of apoptotic pathway in tumor cells, inhibition of cell cycle progression, and suppression of tumor stem cells. Therefore, the application of SFN is expected to be a necessary new approach to treating cancer. In this paper, we review the multiple molecular mechanisms of SFN in cancer prevention and treatment in recent years, which can provide a new vision for cancer treatment.

Mechanistic prediction and validation of Brevilin A Therapeutic effects in Lung Cancer

BACKGROUND

Traditional Chinese medicine (TCM) has been found widespread application in neoplasm treatment, yielding promising therapeutic candidates. Previous studies have revealed the anti-cancer properties of Brevilin A, a naturally occurring sesquiterpene lactone derived from Centipeda minima (L.) A.Br. (C. minima), a TCM herb, specifically against lung cancer. However, the underlying mechanisms of its effects remain elusive. This study employs network pharmacology and experimental analyses to unravel the molecular mechanisms of Brevilin A in lung cancer.

METHODS

The Batman-TCM, Swiss Target Prediction, Pharmmapper, SuperPred, and BindingDB databases were screened to identify Brevilin A targets. Lung cancer-related targets were sourced from GEO, Genecards, OMIM, TTD, and Drugbank databases. Utilizing Cytoscape software, a protein-protein interaction (PPI) network was established. Gene Ontology (GO), Kyoto Encyclopedia of Genes and Genomes (KEGG), Gene set enrichment analysis (GSEA), and gene-pathway correlation analysis were conducted using R software. To validate network pharmacology results, molecular docking, molecular dynamics simulations, and in vitro experiments were performed.

RESULTS

We identified 599 Brevilin A-associated targets and 3864 lung cancer-related targets, with 155 overlapping genes considered as candidate targets for Brevilin A against lung cancer. The PPI network highlighted STAT3, TNF, HIF1A, PTEN, ESR1, and MTOR as potential therapeutic targets. GO and KEGG analyses revealed 2893 enriched GO terms and 157 enriched KEGG pathways, including the PI3K-Akt signaling pathway, FoxO signaling pathway, and HIF-1 signaling pathway. GSEA demonstrated a close association between hub genes and lung cancer. Gene-pathway correlation analysis indicated significant associations between hub genes and the cellular response to hypoxia pathway. Molecular docking and dynamics simulations confirmed Brevilin A's interaction with PTEN and HIF1A, respectively. In vitro experiments demonstrated Brevilin A-induced dose- and time-dependent cell death in A549 cells. Notably, Brevilin A treatment significantly reduced HIF-1α mRNA expression while increasing PTEN mRNA levels.

CONCLUSIONS

This study demonstrates that Brevilin A exerts anti-cancer effects in treating lung cancer through a multi-target and multi-pathway manner, with the HIF pathway potentially being involved. These results lay a theoretical foundation for the prospective clinical application of Brevilin A.

Anti-pancreatic cancer activity of cassane diterpenoids isolated from the seeds of Caesalpinia sappan mediated by autophagy activation via ROS/AMPK/mTORC1 pathway

Three undescribed cassane diterpenoids, caesalpanins D-F (1-3), and seven known ones were isolated from the seeds of Caesalpinia sappan. Structures and absolute configurations of 1-3 were elucidated based on the extensive spectroscopic analysis, single-crystal X-ray diffraction analysis, and ECD calculations. Structurally, compound 1 was the first example of 18-norcassane diterpenoid and 2 was a rare 20-norcassane diterpenoid having an unusual five-membered oxygen bridge between C-10/C-18. The anti-proliferative activity of 1, 3, and 4-10 against PANC-1 cells (pancreatic ductal adenocarcinoma cell line) was evaluated, and phanginin H (4) was found to exhibit anti-cancer activity with IC50 value of 18.13 ± 0.63 μM. Compound 4 inhibited PANC-1 cell growth by arresting the cell cycle at G2/M phase via regulation of cyclin-dependent kinases, and the self-renewal and metastasis of PANC-1 cells by suppressing cancer cell stemness. Furthermore, compound 4 induced ROS generation and subsequently activated autophagy, which was demonstrated by the formation of autophagic vacuoles and dynamic change of autophagic flux. The induced ROS accumulation resulted in AMPK activation and subsequently regulation of mTORC1 activity and ULK phosphorylation, indicating that 4 triggered autophagy through ROS/AMPK/mTORC1 pathway. These findings suggested that 4 might potentially be an autophagy inducer for the therapy of pancreatic cancer.

Pifithrin-µ Induces Stress Granule Formation, Regulates Cell Survival, and Rewires Cellular Signaling

(1) Background: Stress granules (SGs) are cytoplasmic protein-RNA condensates that assemble in response to various insults. SG production is driven by signaling pathways that are relevant to human disease. Compounds that modulate SG characteristics are therefore of clinical interest. Pifithrin-µ is a candidate anti-tumor agent that inhibits members of the hsp70 chaperone family. While hsp70s are required for granulostasis, the impact of pifithrin-µ on SG formation is unknown. (2) Methods: Using HeLa cells as model system, cell-based assays evaluated the effects of pifithrin-µ on cell viability. Quantitative Western blotting assessed cell signaling events and SG proteins. Confocal microscopy combined with quantitative image analyses examined multiple SG parameters. (3) Results: Pifithrin-µ induced bona fide SGs in the absence of exogenous stress. These SGs were dynamic; their properties were determined by the duration of pifithrin-µ treatment. The phosphorylation of eIF2α was mandatory to generate SGs upon pifithrin-µ exposure. Moreover, the formation of pifithrin-µ SGs was accompanied by profound changes in cell signaling. Pifithrin-µ reduced the activation of 5'-AMP-activated protein kinase, whereas the pro-survival protein kinase Akt was activated. Long-term pifithrin-µ treatment caused a marked loss of cell viability. (4) Conclusions: Our study identified stress-related changes in cellular homeostasis that are elicited by pifithrin-µ. These insights are important knowledge for the appropriate therapeutic use of pifithrin-µ and related compounds.

AMPK as a mediator of tissue preservation: time for a shift in dogma?

Ground-breaking discoveries have established 5'-AMP-activated protein kinase (AMPK) as a central sensor of metabolic stress in cells and tissues. AMPK is activated through cellular starvation, exercise and drugs by either directly or indirectly affecting the intracellular AMP (or ADP) to ATP ratio. In turn, AMPK regulates multiple processes of cell metabolism, such as the maintenance of cellular ATP levels, via the regulation of fatty acid oxidation, glucose uptake, glycolysis, autophagy, mitochondrial biogenesis and degradation, and insulin sensitivity. Moreover, AMPK inhibits anabolic processes, such as lipogenesis and protein synthesis. These findings support the notion that AMPK is a crucial regulator of cell catabolism. However, studies have revealed that AMPK's role in cell homeostasis might not be as unidirectional as originally thought. This Review explores emerging evidence for AMPK as a promoter of cell survival and an enhancer of anabolic capacity in skeletal muscle and adipose tissue during catabolic crises. We discuss AMPK-activating interventions for tissue preservation during tissue wasting in cancer-associated cachexia and explore the clinical potential of AMPK activation in wasting conditions. Overall, we provide arguments that call for a shift in the current dogma of AMPK as a mere regulator of cell catabolism, concluding that AMPK has an unexpected role in tissue preservation.

Nicotine-derived NNK promotes CRC progression through activating TMUB1/AKT pathway in METTL14/YTHDF2-mediated m6A manner

Cigarette smoking substantially promotes tumorigenesis and progression of colorectal cancer; however, the underlying molecular mechanism remains unclear. Among 662 colorectal cancer patients, our investigation revealed a significant correlation between cigarette smoking and factors, such as large tumor size, poor differentiation, and high degree of invasion. Among the nicotine-derived nitrosamines, 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK) emerged as the most critical carcinogen, which significantly promoted the malignant progression of colorectal cancer both in vivo and in vitro. The results of methylated RNA immunoprecipitation and transcriptome sequencing indicated that NNK upregulated transmembrane and ubiquitin-like domain-containing protein 1 (TMUB1) via N6-adenosine methylation, which was regulated by methyltransferase-like 14 (METTL14) and YTH N6-methyladenosine RNA binding protein 2 (YTHDF2). Elevated TMUB1 levels were associated with a higher risk of cancer invasion and metastasis, leading to a high mortality risk in patients with colorectal cancer. Additionally, TMUB1 promoted lysine63-linked ubiquitination of AKT by interacting with AMFR, which led to the induction of malignant proliferation and metastasis in colorectal cancer cells exposed to NNK. In summary, this study provides a new insight, indicating that targeting TMUB1 expression via METTL14/YTHDF2 mediated N6-adenosine methylation may be a potential therapeutic and prognostic target for patients with colorectal cancer who smoke.

L-Methionine accentuates anti-tumor action of Gefitinib in Gefitinib-resistant lung adenocarcinoma: Role of EGFR/ERK/AKT signaling and histone H3K36me2 alteration

Adenocarcinoma, the predominant subtype of non-small cell lung cancer (NSCLC), poses a significant clinical challenge due to its prevalence and aggressive nature. Gefitinib, an epidermal growth factor receptor (EGFR) tyrosine kinase inhibitor is often susceptible to development of resistance despite being the preferred treatment option for NSCLC. In this study, we investigated the potential of L-Methionine in enhancing the cytotoxicity of Gefitinib and preventing resistance development. In vitro experiment employing the H1975 cell line demonstrated a notable enhancement in cytotoxic efficacy when L-Methionine (10 mM) was combined with Gefitinib, as indicated by a substantial reduction in IC50 values (155.854 ± 1.87 μM vs 45.83 ± 4.83 μM). Complementary in vivo investigations in a lung cancer model corroborated these findings. Co-administration of L-Methionine (100 mg/kg and 400 mg/kg) with Gefitinib (15 mg/kg) for 21 days exhibited marked improvements in therapeutic efficacy, which was observed by macroscopic and histopathological assessments. Mechanistic insights revealed that the enhanced cytotoxicity of the combination stemmed from the inhibition of the EGFR, modulating the downstream cascade of ERK/AKT and AMPK pathways. Concurrently inhibition of p-AMPK-α by the combination also disrupted metabolic homeostasis, leading to the increased production of reactive oxygen species (ROS). Notably, L-Methionine, functioning as a methyl group donor, elevated the expression of H3K36me2 (an activation mark), while reducing the p-ERK activity. Our study provides the first evidence supporting L-Methionine supplementation as a novel strategy to enhance Gefitinib chemosensitivity against pulmonary adenocarcinoma.

O-GlcNAcylation of E3 ubiquitin ligase SKP2 promotes hepatocellular carcinoma proliferation

O-linked-β-N-acetylglucosamine (O-GlcNAc) modification (O-GlcNAcylation) and ubiquitination are critical posttranslational modifications that regulate tumor development and progression. The continuous progression of the cell cycle is the fundamental cause of tumor proliferation. S-phase kinase-associated protein 2 (SKP2), an important E3 ubiquitin ligase, assumes a pivotal function in the regulation of the cell cycle. However, it is still unclear whether SKP2 is an effector of O-GlcNAcylation that affects tumor progression. In this study, we found that SKP2 interacted with O-GlcNAc transferase (OGT) and was highly O-GlcNAcylated in hepatocellular carcinoma (HCC). Mechanistically, the O-GlcNAcylation at Ser34 stabilized SKP2 by reducing its ubiquitination and degradation mediated by APC-CDH1. Moreover, the O-GlcNAcylation of SKP2 enhanced its binding ability with SKP1, thereby enhancing its ubiquitin ligase function. Consequently, SKP2 facilitated the transition from the G1-S phase of the cell cycle by promoting the ubiquitin degradation of cell cycle-dependent kinase inhibitors p27 and p21. Additionally, targeting the O-GlcNAcylation of SKP2 significantly suppressed the proliferation of HCC. Altogether, our findings reveal that O-GlcNAcylation, a novel posttranslational modification of SKP2, plays a crucial role in promoting HCC proliferation, and targeting the O-GlcNAcylation of SKP2 may become a new therapeutic strategy to impede the progression of HCC.

Hypoglycemic effects and associated mechanisms of resveratrol and related stilbenes in diet

Hyperglycemia has become a global health problem due to changes in diet and lifestyle. Most importantly, persistent hyperglycemia can eventually develop into type II diabetes. While the usage of current drugs is limited by their side effects, stilbenes derived from fruits and herbal/dietary plants are considered as important phytochemicals with potential hypoglycemic properties. Herein, the most common stilbenoids in consumed foods, i.e. resveratrol, pterostilbene, piceatannol, oxyresveratrol, and 2,3,5,4'-tetrahydroxystilbene-2-O-β-glucopyranoside (THSG), are reviewed in this paper. These stilbenes are found to regulate glucose homeostasis via (a) modulation of feeding behaviour and nutrition absorption; (b) restoration of insulin signalling by enhancing insulin production/insulin sensitivity; (c) improvement of gut permeability, gut microbial profile and resulting metabolomes; and (d) amelioration of circadian rhythm disruption. In this review, we have summarized the underlying mechanisms for the hypoglycemic effects of the five most common dietary stilbenoids listed above, providing a comprehensive framework for future study and applications.

l-Methionine potentiates anticancer activity of Sorafenib by epigenetically altering DUSP3/ERK pathway in hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is the third most common cancer-related cause of death worldwide. Although Sorafenib is the standard systemic therapy for treating HCC, but it develops resistance very quickly, leading to poor prognosis. The current study was planned to explore the effect of l-methionine on the anticancer activity of Sorafenib in HCC. Ten millimolar of l-methionine treatment significantly reduced the IC50 of Sorafenib from 5.513 ± 0.171 to 0.8095 ± 0.0465 µM in HepG2 cell line. It also resulted in concomitant increase in oxidative stress and deactivation of ERK/AMPK/AKT pathway. Additionally, it also resulted in the increased expression of dual specificity phosphatase 3 (DUSP3). In a rat model of sorafenib-resistant HCC induced by diethylnitrosamine (DEN) (100 mg/L/day) and Sorafenib (10 mg/kg), l-methionine (300 and 500 mg/kg/day) supplementation overcame the drug resistance, as indicated by the reduced formation of surface tumor nodules, prevention of cellular hypertrophy, hyperplasia and inflammation, and improved animal survival. Furthermore, l-methionine in combination with Sorafenib also inhibited AMPK/AKT and ERK pathway. At chromatin level, l-methionine supplementation prevented global methylation of H3K27me3, an inactivation mark, and demethylation of H3K36me2, an activation mark. Interestingly, our findings suggest that inhibition of the ERK pathway via increased activity of DUSP3 is epigenetically regulated. Besides, chromatin immunoprecipitation data exhibited augmented H3K36me2 (an activation mark) levels on the DUSP3 promoter region. To the best of our knowledge, we are the first to report that l-methionine supplementation improves the chemosensitivity in Sorafenib-resistant HCC via modulating the epigenetic landscape and can be a potential therapeutic strategy.

Skp2: A critical molecule for ubiquitination and its role in cancer

The ubiquitin-proteasome system (UPS) is a multi-step process that serves as the primary pathway for protein degradation within cells. UPS activity also plays a crucial role in regulating various life processes, including the cell cycle, signal transduction, DNA repair, and others. The F-box protein Skp2, a crucial member of the UPS, plays a central role in the development of various diseases. Skp2 controls cancer cell growth and drug resistance by ubiquitinating modifications to a variety of proteins. This review emphasizes the multifaceted role of Skp2 in a wide range of cancers and the mechanisms involved, highlighting the potential of Skp2 as a therapeutic target in cancer. Additionally, we describe the impactful influence exerted by Skp2 in various other diseases beyond cancer.

Overexpression of AMPKγ2 increases AMPK signaling to augment human T cell metabolism and function

Cellular therapies are currently employed to treat a variety of disease processes. For T cell-based therapies, success often relies on the metabolic fitness of the T cell product, where cells with enhanced metabolic capacity demonstrate improved in vivo efficacy. AMP-activated protein kinase (AMPK) is a cellular energy sensor which combines environmental signals with cellular energy status to enforce efficient and flexible metabolic programming. We hypothesized that increasing AMPK activity in human T cells would augment their oxidative capacity, creating an ideal product for adoptive cellular therapies. Lentiviral transduction of the regulatory AMPKγ2 subunit stably enhanced intrinsic AMPK signaling and promoted mitochondrial respiration with increased basal oxygen consumption rates, higher maximal oxygen consumption rate, and augmented spare respiratory capacity. These changes were accompanied by increased proliferation and inflammatory cytokine production, particularly within restricted glucose environments. Introduction of AMPKγ2 into bulk CD4 T cells decreased RNA expression of canonical Th2 genes, including the cytokines interleukin (IL)-4 and IL-5, while introduction of AMPKγ2 into individual Th subsets universally favored proinflammatory cytokine production and a downregulation of IL-4 production in Th2 cells. When AMPKγ2 was overexpressed in regulatory T cells, both in vitro proliferation and suppressive capacity increased. Together, these data suggest that augmenting intrinsic AMPK signaling via overexpression of AMPKγ2 can improve the expansion and functional potential of human T cells for use in a variety of adoptive cellular therapies.

RGCC-mediated PLK1 activity drives breast cancer lung metastasis by phosphorylating AMPKα2 to activate oxidative phosphorylation and fatty acid oxidation

BACKGROUND

More than 90% of the mortality of triple-negative breast cancer (TNBC) patients is attributed to cancer metastasis with organotropism. The lung is a frequent site of TNBC metastasis. However, the precise molecular mechanism for lung-specific metastasis of TNBC is not well understood.

METHODS

RNA sequencing was performed to identify patterns of gene expression associated with lung metastatic behavior using 4T1-LM3, MBA-MB-231-LM3, and their parental cells (4T1-P, MBA-MB-231-P). Expressions of RGCC, called regulator of cell cycle or response gene to complement 32 protein, were detected in TNBC cells and tissues by qRT-PCR, western blotting, and immunohistochemistry. Kinase activity assay was performed to evaluate PLK1 kinase activity. The amount of phosphorylated AMP-activated protein kinase α2 (AMPKα2) was detected by immunoblotting. RGCC-mediated metabolism was determined by UHPLC system. Oxidative phosphorylation was evaluated by JC-1 staining and oxygen consumption rate (OCR) assay. Fatty acid oxidation assay was conducted to measure the status of RGCC-mediated fatty acid oxidation. NADPH and ROS levels were detected by well-established assays. The chemical sensitivity of cells was evaluated by CCK8 assay.

RESULTS

RGCC is aberrantly upregulated in pulmonary metastatic cells. High level of RGCC is significantly related with lung metastasis in comparison with other organ metastases. RGCC can effectively promote kinase activity of PLK1, and the activated PLK1 phosphorylates AMPKα2 to facilitate TNBC lung metastasis. Mechanistically, the RGCC/PLK1/AMPKα2 signal axis increases oxidative phosphorylation of mitochondria to generate more energy, and promotes fatty acid oxidation to produce abundant NADPH. These metabolic changes contribute to sustaining redox homeostasis and preventing excessive accumulation of potentially detrimental ROS in metastatic tumor cells, thereby supporting TNBC cell survival and colonization during metastases. Importantly, targeting RGCC in combination with paclitaxel/carboplatin effectively suppresses pulmonary TNBC lung metastasis in a mouse model.

CONCLUSIONS

RGCC overexpression is significantly associated with lung-specific metastasis of TNBC. RGCC activates AMPKα2 and downstream signaling through RGCC-driven PLK1 activity to facilitate TNBC lung metastasis. The study provides implications for RGCC-driven OXPHOS and fatty acid oxidation as important therapeutic targets for TNBC treatment.

Current status and frontier tracking of clinical trials on Metformin for cancer treatment

PURPOSE

Metformin has been used clinically for more than six decades. Over time, numerous remarkable effects of metformin beyond the clinic have been discovered and discussed. Metformin has been shown to have a favorable impact on cancer therapy in addition to its clinically recognized hypoglycemic effect. However, the antitumor efficacy of metformin in humans has not been clearly demonstrated yet. Hence, a systematic analysis of the existing trials is necessary.

METHODS

Here, we retrieved clinical trials from the Clinical Trials.gov database to overview the clinical development of metformin for the treatment of cancer, analyze existing clinical results, and summarize some promising applications for specific cancer therapies.

RESULTS

The potential application of metformin contains three directions: Firstly, improvement of metabolic factors associated with treatment effects, such as insulin resistance and peripheral neuropathy. Secondly, in combination with immune checkpoint blockade effects. Finally, use it for the endocrine treatment of hormone-dependent cancers.

CONCLUSION

Although the outcomes of metformin as a repurposed agent in some trials have been unsatisfactory, it still has the potential to be used in select cancer therapy settings.

CAB39 promotes cisplatin resistance in bladder cancer via the LKB1-AMPK-LC3 pathway

Systemic therapy for muscle-invasive bladder cancer (BC) remains dominated by cisplatin-based chemotherapy. However, resistance to cisplatin therapy greatly limits long-term survival. Resistance to cisplatin-based chemotherapy still needs to be addressed. In this study, we established three cisplatin-resistant BC cell lines by multiple cisplatin pulse treatments. Interestingly, after exposure to cisplatin, all cisplatin-resistant cell lines showed lower reactive oxygen species (ROS) levels than the corresponding parental cell lines. Using proteomic analysis, we identified 35 proteins that were upregulated in cisplatin-resistant BC cells. By knocking down eleven of these genes, we found that after CAB39 knockdown, BC cisplatin-resistant cells were more sensitive to cisplatin. Overexpression of CAB39 had the opposite effect. Then, the knockdown of six genes downstream of CAB39 revealed that CAB39 promoted cisplatin resistance in BC through LKB1. Moreover, a key cause of cisplatin-induced cell death is damage to mitochondria and increased ROS levels. In our study, cisplatin-resistant cells exhibited higher autophagic flux and healthier mitochondrial status after cisplatin exposure. We demonstrated that the CAB39-LKB1-AMPK-LC3 pathway plays a critical role in enhancing autophagy to maintain the health of mitochondria and reduce ROS levels. In addition, the autophagy inhibitor chloroquine (CQ) can significantly enhance the killing effect of cisplatin on BC cells. Compared with gemcitabine plus cisplatin (GC), GC plus CQ significantly reduced tumor burden in vivo. In conclusion, our study shows that CAB39 counteracts the killing of cisplatin by enhancing the autophagy of BC cells to damaged mitochondria and other organelles to alleviate the damage of cells caused by harmful substances such as ROS.

The proteasome regulates body weight and systemic nutrient metabolism during fasting

The ubiquitin-proteasome system (UPS) and the autophagy-lysosome pathway are the primary means of degradation in mammalian tissues. We sought to determine the individual contribution of the UPS and autophagy to tissue catabolism during fasting. Mice were overnight fasted for 15 h before regaining food access ("Fed" group, n = 6) or continuing to fast ("Fast" group, n = 7) for 3 h. In addition, to investigate the effects of autophagy on systemic metabolism and tissue degradation, one group of mice was fasted for 18 h and treated with chloroquine ("Fast + CLQ" group, n = 7) and a fourth group of mice was treated with bortezomib ("Fast + Bort" group, n = 7) to assess the contribution of the UPS. Body weight, tissue weight, circulating hormones and metabolites, intracellular signaling pathways, and protein synthesis were investigated. Fasting induced the loss of body weight, liver mass, and white adipose tissue in the Fast and the Fast + CLQ group, whereas the Fast + Bort group maintained tissue and body weight. Fasting reduced glucose and increased β hydroxybutyrate in the circulation of all mice. Both changes were most profound in the Fast + Bort group compared with the other fasting conditions. Molecular signaling indicated a successful inhibition of hepatic UPS with bortezomib and an upregulation of the PI3K/AKT/mTOR pathway. The latter was further supported by an increase in hepatic protein synthesis with bortezomib. Inhibition of the UPS through bortezomib blocks body weight loss and tissue catabolism during an acute overnight fast in mice. The effects were likely mediated through a combined effect of the drug on biomolecule degradation and synthesis.NEW & NOTEWORTHY Bortezomib treatment prevents tissue and body weight loss during fasting. The loss of proteasome activity with bortezomib exacerbates fasting-induced ketogenesis. During fasting, bortezomib increases AMPK and PI3K/AKT signaling in the liver, which promotes protein synthesis.

Metformin does not slow cyst growth in the PCK rat model of polycystic kidney disease

Metformin (MET) has the potential to activate p-AMPK and block mTORC1-induced proliferation of tubular cells in PKD kidneys. The aim of this study was to determine the effects of MET on cyst growth, kidney function, AMPK and mTOR signaling, and lactate levels in male PCK rats, a Pkhd1 gene mutation model of human autosomal recessive polycystic kidney disease (ARPKD). MET 300 mg/kg/day IP from days 28 to 84 of age resulted in a mean serum metformin level that was 10 times the upper limit of therapeutic, no effect on cyst indices, nephrotoxicity, and increased serum lactate. MET 150 mg/kg resulted in a therapeutic serum metformin level but had no effect on kidney weight, cyst indices, kidney function, or mTOR and autophagy proteins. In summary, a standard dose of MET was ineffective in reducing PKD, did not activate p-AMPK or suppress mTOR and the higher dose resulted in increased lactate levels and nephrotoxicity. In conclusion, the study dampens enthusiasm for human studies of MET in PKD. Doubling the metformin dose resulted in a 10-fold increase in mean blood levels and toxicity suggesting that the dosage range between therapeutic and toxic is narrow.

Metabolic protein kinase signalling in neuroblastoma

BACKGROUND

Neuroblastoma is a paediatric malignancy of incredibly complex aetiology. Oncogenic protein kinase signalling in neuroblastoma has conventionally focussed on transduction through the well-characterised PI3K/Akt and MAPK pathways, in which the latter has been implicated in treatment resistance. The discovery of the receptor tyrosine kinase ALK as a target of genetic alterations in cases of familial and sporadic neuroblastoma, was a breakthrough in the understanding of the complex genetic heterogeneity of neuroblastoma. However, despite progress in the development of small-molecule inhibitors of ALK, treatment resistance frequently arises and appears to be a feature of the disease. Moreover, since the identification of ALK, several additional protein kinases, including the PIM and Aurora kinases, have emerged not only as drivers of the disease phenotype, but also as promising druggable targets. This is particularly the case for Aurora-A, given its intimate engagement with MYCN, a driver oncogene of aggressive neuroblastoma previously considered 'undruggable.'

SCOPE OF REVIEW

Aided by significant advances in structural biology and a broader understanding of the mechanisms of protein kinase function and regulation, we comprehensively outline the role of protein kinase signalling, emphasising ALK, PIM and Aurora in neuroblastoma, their respective metabolic outputs, and broader implications for targeted therapies.

MAJOR CONCLUSIONS

Despite massively divergent regulatory mechanisms, ALK, PIM and Aurora kinases all obtain significant roles in cellular glycolytic and mitochondrial metabolism and neuroblastoma progression, and in several instances are implicated in treatment resistance. While metabolism of neuroblastoma tends to display hallmarks of the glycolytic "Warburg effect," aggressive, in particular MYCN-amplified tumours, retain functional mitochondrial metabolism, allowing for survival and proliferation under nutrient stress. Future strategies employing specific kinase inhibitors as part of the treatment regimen should consider combinatorial attempts at interfering with tumour metabolism, either through metabolic pathway inhibitors, or by dietary means, with a view to abolish metabolic flexibility that endows cancerous cells with a survival advantage.

Skp2-mediated MLKL degradation confers cisplatin-resistant in non-small cell lung cancer cells

Non-small cell lung cancer (NSCLC) is the most prevalent type of cancer and the leading cause of cancer-related death. Chemotherapeutic resistance is a major obstacle in treating NSCLC patients. Here, we discovered that the E3 ligase Skp2 is overexpressed, accompanied by the downregulation of necroptosis-related regulator MLKL in human NSCLC tissues and cell lines. Knockdown of Skp2 inhibited viability, anchorage-independent growth, and in vivo tumor development of NSCLC cells. We also found that the Skp2 protein is negatively correlated with MLKL in NSCLC tissues. Moreover, Skp2 is increased and accompanied by an upregulation of MLKL ubiquitination and degradation in cisplatin-resistant NSCLC cells. Accordingly, inhibition of Skp2 partially restores MLKL and sensitizes NSCLC cells to cisplatin in vitro and in vivo. Mechanistically, Skp2 interacts and promotes ubiquitination-mediated degradation of MLKL in cisplatin-resistant NSCLC cells. Our results provide evidence of an Skp2-dependent mechanism regulating MLKL degradation and cisplatin resistance, suggesting that targeting Skp2-ubiquitinated MLKL degradation may overcome NSCLC chemoresistance.

Biological Activities of Ceratonia siliqua Pod and Seed Extracts: A Comparative Analysis of Two Cretan Cultivars

Ceratonia siliqua L., commonly known as the carob tree, appears in most Mediterranean countries, often cultivated for the collection of its fruits to be used as food for humans and animals. This study was aimed at the phytochemical characterization of two common Cretan C. siliqua cultivars and the biological evaluation of deseeded pod and seed extracts regarding their putative use in cosmetics. Gas and liquid chromatographic techniques were used to assess their essential oil, fatty acid, and carbohydrate profiles. Cell-free assays, including free-radical scavenging; the inhibition of tyrosinase and collagenase; the blocking of advanced glycation end product (AGE) formation; along with assays in human skin fibroblast cultures, i.e., reactive oxygen species suppression, glutathione stimulation, and protection from oxidative stress and from ultraviolet (UVB) radiation, were also used. Extracts from both cultivars were found to possess antioxidant capacity, tyrosinase- and collagenase-inhibitory activities, an ability to block glucose-induced AGEs, and in certain cases, UVB absorbance and photoprotective activities. Seed extracts were in general more active, while the use of 30% aqueous methanol seemed to be more efficient than n-hexane for extraction. Serial partition of the most active extracts resulted in fractions with enriched biological activities. These properties make Cretan carob extracts and their fractions suitable candidates for use in cosmetics.

Loss of AMPKα2 promotes melanoma tumor growth and brain metastasis

AMP-activated protein kinase (AMPK) is a critical cellular energy sensor at the interface of metabolism and cancer. However, the role of AMPK in carcinogenesis remains unclear. Here, through analysis of the TCGA melanoma dataset, we found that PRKAA2 gene that encodes the α2 subunit of AMPK is mutated in ∼9% of cutaneous melanomas, and these mutations tend to co-occur with NF1 mutations. Knockout of AMPKα2 promoted anchorage-independent growth of NF1-mutant melanoma cells, whereas ectopic expression of AMPKα2 inhibited their growth in soft agar assays. Moreover, loss of AMPKα2 accelerated tumor growth of NF1-mutant melanoma and enhanced their brain metastasis in immune-deficient mice. Our findings support that AMPKα2 serves as a tumor suppressor in NF1-mutant melanoma and suggest that AMPK could be a therapeutic target for treating melanoma brain metastasis.

Chitosan Oligosaccharide Promotes Junction Barrier through Modulation of PI3K/AKT and ERK Signaling Intricate Interplay in T84 Cells

Chitosan oligosaccharide (COS) is a breakdown product of chitin, a polymer of N-acetyl-D-glucosamine. COS promotes barrier function in intestinal epithelial cells. However, the exact mechanism of COS-induced barrier function remains unknown. This study was aimed to explore the intricate signaling cascades in the junction barrier induced by COS (100 μg/mL) in human intestinal epithelial cells (T84 cells). COS (100 μg/mL) promoted tight junction assembly and increased transepithelial electrical resistance (TEER). COS inhibited FITC-dextran flux in T84 cell monolayers at 2 h, 4 h, 6 h and 24 h post treatment. In addition, the effect of COS on TEER and FITC-dextran flux was abrogated by pre-incubation of wortmannin (2 μM), an AKT (protein kinase B) inhibitor, at 2 h and 4 h post treatment, indicating that COS-induced tight junction integrity was mediated at least in part by AKT activation. COS-induced TEER was amplified at 24 h and 48 h post treatment by pre-incubation with SC79 (2.5 μM), an AKT activator. Moreover, COS induced inhibition of extracellular signal-regulated kinase (ERK) in T84 cells. Wortmannin and SC79 pre-incubation promoted ERK activation and ERK inhibition, respectively, suggesting that COS-induced ERK inhibition was mediated by AKT. Collectively, this study reveals that COS promotes junction barrier integrity via regulating PI3K/AKT and ERK signaling intricate interplay in T84 cell monolayers. COS may be beneficial in promoting junction barrier in intestinal disorders.

Roxadustat (FG-4592) abated lipopolysaccharides-induced depressive-like symptoms via PI3K signaling

Background

Despite its role in inflammation and the redox system under hypoxia, the effects and molecular mechanisms of hypoxia-inducible factor (HIF) in neuroinflammation-associated depression are poorly explored. Furthermore, Prolyl hydroxylase domain-containing proteins (PHDs) regulate HIF-1; however, whether and how PHDs regulate depressive-like behaviors under Lipopolysaccharides (LPS)-induced stress conditions remain covered.

Methods

To highlight the roles and underlying mechanisms of PHDs-HIF-1 in depression, we employed behavioral, pharmacological, and biochemical analyses using the LPS-induced depression model.

Results

Lipopolysaccharides treatment induced depressive-like behaviors, as we found, increased immobility and decreased sucrose preference in the mice. Concurrently, we examined increased cytokine levels, HIF-1 expression, mRNA levels of PHD1/PHD2, and neuroinflammation upon LPS administration, which Roxadustat reduced. Furthermore, the PI3K inhibitor wortmannin reversed Roxadustat-induced changes. Additionally, Roxadustat treatment attenuated LPS-induced synaptic impairment and improved spine numbers, ameliorated by wortmannin.

Conclusion

Lipopolysaccharides-dysregulates HIF-PHDs signaling may contribute to neuroinflammation-coincides depression via PI3K signaling.

Cross-talk between AMP-activated protein kinase and the sonic hedgehog pathway in the high-fat diet triggered colorectal cancer

The major cause of colorectal cancer (CRC) related mortality is due to its metastasis. Signaling pathways play a definite role in the development and progression of CRC. Recent studies demonstrate that the regulation of the sonic hedgehog (Shh) pathway is beneficial in the CRC treatment strategy. Also, 5'-adenosine monophosphate (AMP)-activated protein kinase (AMPK) is a well-known regulator of metabolism and inflammation, making it a suitable treatment option for CRC. Consumption of a high-fat diet (HFD) is a significant cause of CRC genesis. Also, the lipids play an indispensable role in aberrant activation of the Shh pathway. This review explains in detail the interconnection between HFD consumption, Shh pathway activation, and the progression of CRC. According to recent studies and literature, AMPK is a potential regulator that can control the complexities of CRC and reduce lipid levels and may directly inhibit shh signalling. The review also suggests the possible risk elements of AMPK activation in CRC due to its context-dependent role. Also, the activation of AMPK in HFD-induced CRC may modulate cancer progression by regulating the Shh pathway and metabolism.

Mechanisms of PiT2-loop7 Missense Mutations Induced Pi Dyshomeostasis

PiT2 is an inorganic phosphate (Pi) transporter whose mutations are linked to primary familial brain calcification (PFBC). PiT2 mainly consists of two ProDom (PD) domains and a large intracellular loop region (loop7). The PD domains are crucial for the Pi transport, but the role of PiT2-loop7 remains unclear. In PFBC patients, mutations in PiT2-loop7 are mainly nonsense or frameshift mutations that probably cause PFBC due to C-PD1131 deletion. To date, six missense mutations have been identified in PiT2-loop7; however, the mechanisms by which these mutations cause PFBC are poorly understood. Here, we found that the p.T390A and p.S434W mutations in PiT2-loop7 decreased the Pi transport activity and cell surface levels of PiT2. Furthermore, we showed that these two mutations attenuated its membrane localization by affecting adenosine monophosphate-activated protein kinase (AMPK)- or protein kinase B (AKT)-mediated PiT2 phosphorylation. In contrast, the p.S121C and p.S601W mutations in the PD domains did not affect PiT2 phosphorylation but rather impaired its substrate-binding abilities. These results suggested that missense mutations in PiT2-loop7 can cause Pi dyshomeostasis by affecting the phosphorylation-regulated cell-surface localization of PiT2. This study helps understand the pathogenesis of PFBC caused by PiT2-loop7 missense mutations and indicates that increasing the phosphorylation levels of PiT2-loop7 could be a promising strategy for developing PFBC therapies.