An ID2-dependent mechanism for VHL inactivation in cancer

ID2 promotes tumor progression and metastasis in thyroid cancer

BACKGROUND

Inhibitor of DNA Binding 2 (ID2) plays a crucial role in tumor cell proliferation, invasion, metastasis, and stemness. Aberrant ID2 expression is associated with poor prognosis in various cancers. However, the specific function of ID2 in thyroid cancer remain unclear.

METHOD

The TCGA database were utilized to explore the clinical relevance of ID2 in cancer. GO, KEGG, and TIMER were employed to predict the potential roles of ID2 in cancer. Functional analysis, including CCK-8, colony formation, transwell, wound healing, and sphere formation experiments, were conducted to determine the biological functions of ID2 in human cancers. Western blot (WB), RT-qPCR, and immunohistochemical (IHC) analyses were used to investigate the relationship between ID2 and downstream targets.

RESULTS

Our study revealed significant overexpression of ID2 in various malignant tumor cells. Knocking ID2 significantly inhibited cancer cell proliferation and invasion, while overexpressing ID2 enhanced these capabilities. Additionally, ID2 mediates resistance of cancer cells to protein kinase B (or Akt) inhibitions. Further WB and IHC experiments indicated that ID2 promotes the phosphorylation activation of phosphatidylinositol 3-kinase (PI3K)/Akt signaling pathway, thereby upregulating the expression of downstream proliferation, epithelial-mesenchymal transition (EMT), and stemness-related markers.

CONCLUSION

We found that ID2 significantly promotes thyroid cancer cell proliferation, migration, EMT, and stemness through the PI3K/Akt pathway. Moreover, ID2 plays a crucial role in regulating cancer immune responses. It may serve as a potential biomarker for enhancing the efficacy of chemotherapy, targeted therapy, and immunotherapy against cancer.

Mirk/Dyrk1B Kinase Inhibitors in Targeted Cancer Therapy

During the last years, there has been an increased effort in the discovery of selective and potent kinase inhibitors for targeted cancer therapy. Kinase inhibitors exhibit less toxicity compared to conventional chemotherapy, and several have entered the market. Mirk/Dyrk1B kinase is a promising pharmacological target in cancer since it is overexpressed in many tumors, and its overexpression is correlated with patients' poor prognosis. Mirk/Dyrk1B acts as a negative cell cycle regulator, maintaining the survival of quiescent cancer cells and conferring their resistance to chemotherapies. Many studies have demonstrated the valuable therapeutic effect of Mirk/Dyrk1B inhibitors in cancer cell lines, mouse xenografts, and patient-derived 3D-organoids, providing a perspective for entering clinical trials. Since the majority of Mirk/Dyrk1B inhibitors target the highly conserved ATP-binding site, they exhibit off-target effects with other kinases, especially with the highly similar Dyrk1A. In this review, apart from summarizing the data establishing Dyrk1B as a therapeutic target in cancer, we highlight the most potent Mirk/Dyrk1B inhibitors recently reported. We also discuss the limitations and perspectives for the structure-based design of Mirk/Dyrk1B potent and highly selective inhibitors based on the accumulated structural data of Dyrk1A and the recent crystal structure of Dyrk1B with AZ191 inhibitor.

Methyltransferase-like 3 modifications of RNAs: Implications for the pathology in the endocrine system

Methyltransferase-like 3 (METTL3) is the most well-known element of N6-methyladenosine modification on RNAs. METTL3 deposits a methyl group onto target RNAs to modify their expression, ultimately regulating various physiological and pathological events. Numerous studies have suggested the significant role of METTL3 in endocrine dysfunction and related disorders. However, reviews that summarize and interpret these studies are lacking. In this review, we systematically analyze such studies, including obesity, type 2 diabetes mellitus (T2DM), T2DM-induced diseases, pancreatic cancer, and thyroid carcinoma. This review indicates that METTL3 contributes remarkably to the endocrine dysfunction and progression of obesity, T2DM, T2DM-induced diseases, pancreatic cancer, and thyroid carcinoma. In conclusion, this review provides a comprehensive interpretation of the mechanism via which METTL3 functions on RNAs and regulates various endocrine dysfunction events and suggest potential associated correlations. Our review, thus, provides a valuable reference for further fundamental studies and clinical applications.

Targeting the survival kinase DYRK1B: A novel approach to overcome radiotherapy-related treatment resistance

BACKGROUND

Cancer cell survival under stress conditions is a prerequisite for the development of treatment resistance. The survival kinase DYRK1B is a key regulator of stress survival pathways and might thereby also contribute to radiation resistance. Here we investigate the strategy of targeting DYRK1B in combination with ionizing radiation (IR) to enhance tumor cell killing under stress conditions.

METHODS

DYRK1B expression, ROS formation and DNA damage were investigated under serum-starvation (0.1% FBS), hypoxia (0.2%, 1% O2) and IR. The combined treatment modality of IR and DYRK1B inhibition was investigated in 2D and in spheroids derived from the colorectal cancer cell line SW620, and in primary patient-derived colorectal carcinoma (CRC) organoids.

RESULTS

Expression of DYRK1B was upregulated under starvation and hypoxia, but not in response to IR. The small molecule DYRK1B inhibitor AZ191 and shRNA-mediated DYRK1B knockdown significantly reduced proliferative activity and clonogenicity of SW620 tumor cells alone and in combination with IR under serum-starved conditions, which correlated with increased ROS levels and DNA damage. Furthermore, AZ191 successfully targeted the hypoxic core of tumor spheroids while IR preferentially targeted normoxic cells in the rim of the spheroids. A combined treatment effect was also observed in CRC-organoids but not in healthy tissue-derived organoids.

CONCLUSION

Combined treatment with the DYRK1B inhibitor AZ191 and IR resulted in (supra-) additive tumor cell killing in colorectal tumor cell systems and in primary CRC organoids. Mechanistic investigations support the rational to target the stress-enhanced survival kinase DYRK1B in combination with irradiation to overcome hypoxia- and starvation-induced treatment resistances.

Regulation of CMGC kinases by hypoxia

Hypoxia, a widespread occurrence observed in various malignant tumors, results from rapid tumor growth that outpaces the oxygen supply. Tumor hypoxia precipitates several effects on tumor biology; these include activating angiogenesis, intensifying invasiveness, enhancing the survival of tumor cells, suppressing anti-tumor immunity, and fostering resistance to therapy. Aligned with the findings that correlate CMGC kinases with the regulation of Hypoxia-Inducible Factor (HIF), a pivotal modulator, reports also indicate that hypoxia governs the activity of CMGC kinases, including DYRK1 kinases. Prolyl hydroxylation of DYRK1 kinases by PHD1 constitutes a novel mechanism of kinase maturation and activation. This modification "primes" DYRK1 kinases for subsequent tyrosine autophosphorylation, a vital step in their activation cascade. This mechanism adds a layer of intricacy to comprehending the regulation of CMGC kinases, and underscores the complex interplay between distinct post-translational modifications in harmonizing precise kinase activity. Overall, hypoxia assumes a substantial role in cancer progression, influencing diverse aspects of tumor biology that include angiogenesis, invasiveness, cell survival, and resistance to treatment. CMGC kinases are deeply entwined in its regulation. To fathom the molecular mechanisms underpinning hypoxia's impact on cancer cells, comprehending how hypoxia and prolyl hydroxylation govern the activity of CMGC kinases, including DYRK1 kinases, becomes imperative. This insight may pave the way for pioneering therapeutic approaches that target the hypoxic tumor microenvironment and its associated challenges. [BMB Reports 2023; 56(11): 584-593].

Insights from the protein interaction Universe of the multifunctional "Goldilocks" kinase DYRK1A

Human Dual specificity tyrosine (Y)-Regulated Kinase 1A (DYRK1A) is encoded by a dosage-dependent gene located in the Down syndrome critical region of human chromosome 21. The known substrates of DYRK1A include proteins involved in transcription, cell cycle control, DNA repair and other processes. However, the function and regulation of this kinase is not fully understood, and the current knowledge does not fully explain the dosage-dependent function of this kinase. Several recent proteomic studies identified DYRK1A interacting proteins in several human cell lines. Interestingly, several of known protein substrates of DYRK1A were undetectable in these studies, likely due to a transient nature of the kinase-substrate interaction. It is possible that the stronger-binding DYRK1A interacting proteins, many of which are poorly characterized, are involved in regulatory functions by recruiting DYRK1A to the specific subcellular compartments or distinct signaling pathways. Better understanding of these DYRK1A-interacting proteins could help to decode the cellular processes regulated by this important protein kinase during embryonic development and in the adult organism. Here, we review the current knowledge of the biochemical and functional characterization of the DYRK1A protein-protein interaction network and discuss its involvement in human disease.

Identification of Maleimide-Fused Carbazoles as Novel Noncanonical Bone Morphogenetic Protein Synergizers

Morphogenic signaling pathways govern embryonic development and tissue homeostasis on the cellular level. Precise control of such signaling events paves the way for innovative therapeutic approaches in the field of regenerative medicine. In line with these notions, bone morphogenic protein (BMP) is a major osteogenic driver and pharmacological stimulation of BMP signaling holds supreme potential for diseases and defects of the skeleton. Efforts to identify small-molecule modalities that activate or potentiate the BMP pathway have primarily been focused on the canonical signaling cascade. Here, we describe the phenotypic identification and development of specific carbazolomaleimides 2 as novel noncanonical BMP synergizers with submicromolar osteogenic cellular potency. The devised chemical tools are characterized to specifically regulate Id gene expression in a SMAD-independent, yet highly BMP-dependent fashion. Mechanistic studies revealed that GSK3 inhibition and increased β-catenin levels are partly responsible for this activity. The utility of the new BMP synergizer profile was further exemplified by showing how the synergistic action of canonical and noncanonical BMP enhancers additively amplifies BMP-dependent osteogenic outputs. Carbazolomaleimide 2b serves as a new and unique pharmacological tool for the modulation and study of the BMP pathway.

DYRK1A-mediated PLK2 phosphorylation regulates the proliferation and invasion of glioblastoma cells

Polo-like kinases (PLKs) are a family of serine-threonine kinases that exert regulatory effects on diverse cellular processes. Dysregulation of PLKs has been implicated in multiple cancers, including glioblastoma (GBM). Notably, PLK2 expression in GBM tumor tissue is lower than that in normal brains. Notably, high PLK2 expression is significantly correlated with poor prognosis. Thus, it can be inferred that PLK2 expression alone may not be sufficient for accurate prognosis evaluation, and there are unknown mechanisms underlying PLK2 regulation. In the present study, it was demonstrated that dual specificity tyrosine-phosphorylation-regulated kinase 1A (DYRK1A) interacts with and phosphorylates PLK2 at Ser358. DYRK1A-mediated phosphorylation of PLK2 increases its protein stability. Moreover, PLK2 kinase activity was markedly induced by DYRK1A, which was exemplified by the upregulation of alpha-synuclein S129 phosphorylation. Furthermore, it was found that phosphorylation of PLK2 by DYRK1A contributes to the proliferation, migration and invasion of GBM cells. DYRK1A further enhances the inhibition of the malignancy of GBM cells already induced by PLK2. The findings of the present study indicate that PLK2 may play a crucial role in GBM pathogenesis partially in a DYRK1A-dependent manner, suggesting that PLK2 Ser358 may serve as a therapeutic target for GBM.

ER chaperone GRP78/BiP translocates to the nucleus under stress and acts as a transcriptional regulator

Cancer cells are commonly subjected to endoplasmic reticulum (ER) stress. To gain survival advantage, cancer cells exploit the adaptive aspects of the unfolded protein response such as upregulation of the ER luminal chaperone GRP78. The finding that when overexpressed, GRP78 can escape to other cellular compartments to gain new functions regulating homeostasis and tumorigenesis represents a paradigm shift. Here, toward deciphering the mechanisms whereby GRP78 knockdown suppresses EGFR transcription, we find that nuclear GRP78 is prominent in cancer and stressed cells and uncover a nuclear localization signal critical for its translocation and nuclear activity. Furthermore, nuclear GRP78 can regulate expression of genes and pathways, notably those important for cell migration and invasion, by interacting with and inhibiting the activity of the transcriptional repressor ID2. Our study reveals a mechanism for cancer cells to respond to ER stress via transcriptional regulation mediated by nuclear GRP78 to adopt an invasive phenotype.

LZTR1 Mutation Mediates Oncogenesis through Stabilization of EGFR and AXL

LZTR1 is the substrate-specific adaptor of a CUL3-dependent ubiquitin ligase frequently mutated in sporadic and syndromic cancer. We combined biochemical and genetic studies to identify LZTR1 substrates and interrogated their tumor-driving function in the context of LZTR1 loss-of-function mutations. Unbiased screens converged on EGFR and AXL receptor tyrosine kinases as LZTR1 interactors targeted for ubiquitin-dependent degradation in the lysosome. Pathogenic cancer-associated mutations of LZTR1 failed to promote EGFR and AXL degradation, resulting in dysregulated growth factor signaling. Conditional inactivation of Lztr1 and Cdkn2a in the mouse nervous system caused tumors in the peripheral nervous system including schwannoma-like tumors, thus recapitulating aspects of schwannomatosis, the prototype tumor predisposition syndrome sustained by LZTR1 germline mutations. Lztr1- and Cdkn2a-deleted tumors aberrantly accumulated EGFR and AXL and exhibited specific vulnerability to EGFR and AXL coinhibition. These findings explain tumorigenesis by LZTR1 inactivation and offer therapeutic opportunities to patients with LZTR1-mutant cancer.

SIGNIFICANCE

EGFR and AXL are substrates of LZTR1-CUL3 ubiquitin ligase. The frequent somatic and germline mutations of LZTR1 in human cancer cause EGFR and AXL accumulation and deregulated signaling. LZTR1-mutant tumors show vulnerability to concurrent inhibition of EGFR and AXL, thus providing precision targeting to patients affected by LZTR1-mutant cancer. This article is highlighted in the In This Issue feature, p. 517.

Hypoxia signaling in cancer: Implications for therapeutic interventions

Hypoxia is a persistent physiological feature of many different solid tumors and a key driver of malignancy, and in recent years, it has been recognized as an important target for cancer therapy. Hypoxia occurs in the majority of solid tumors due to a poor vascular oxygen supply that is not sufficient to meet the needs of rapidly proliferating cancer cells. A hypoxic tumor microenvironment (TME) can reduce the effectiveness of other tumor therapies, such as radiotherapy, chemotherapy, and immunotherapy. In this review, we discuss the critical role of hypoxia in tumor development, including tumor metabolism, tumor immunity, and tumor angiogenesis. The treatment methods for hypoxic TME are summarized, including hypoxia-targeted therapy and improving oxygenation by alleviating tumor hypoxia itself. Hyperoxia therapy can be used to improve tissue oxygen partial pressure and relieve tumor hypoxia. We focus on the underlying mechanisms of hyperoxia and their impact on current cancer therapies and discuss the prospects of hyperoxia therapy in cancer treatment.

Molecular mechanism(s) of regulations of cancer stem cell in brain cancer propagation

Brain tumors are most often diagnosed with solid neoplasms and are the primary reason for cancer-related deaths in both children and adults worldwide. With recent developments in the progression of novel targeted chemotherapies, the prognosis of malignant glioma remains dismal. However, the high recurrence rate and high mortality rate remain unresolved and are closely linked to the biological features of cancer stem cells (CSCs). Research on tumor biology has reached a new age with more understanding of CSC features. CSCs, a subpopulation of whole tumor cells, are now regarded as candidate therapeutic targets. Therefore, in the diagnosis and treatment of tumors, recognizing the biological properties of CSCs is of considerable significance. Here, we have discussed the concept of CSCs and their significant role in brain cancer growth and propagation. We have also discussed personalized therapeutic development and immunotherapies for brain cancer by specifically targeting CSCs.

The Omnipresence of DYRK1A in Human Diseases

The increasing population will challenge healthcare, particularly because the worldwide population has never been older. Therapeutic solutions to age-related disease will be increasingly critical. Kinases are key regulators of human health and represent promising therapeutic targets for novel drug candidates. The dual-specificity tyrosine-regulated kinase (DYRKs) family is of particular interest and, among them, DYRK1A has been implicated ubiquitously in varied human diseases. Herein, we focus on the characteristics of DYRK1A, its regulation and functional role in different human diseases, which leads us to an overview of future research on this protein of promising therapeutic potential.

Ferroptosis in Glioma Immune Microenvironment: Opportunity and Challenge

Glioma is the most common intracranial malignant tumor in adults and the 5-year survival rate of glioma patients is extremely poor, even in patients who received Stupp treatment after diagnosis and this forces us to explore more efficient clinical strategies. At this time, immunotherapy shows great potential in a variety of tumor clinical treatments, however, its clinical effect in glioma is limited because of tumor immune privilege which was induced by the glioma immunosuppressive microenvironment, so remodeling the immunosuppressive microenvironment is a practical way to eliminate glioma immunotherapy resistance. Recently, increasing studies have confirmed that ferroptosis, a new form of cell death, plays an important role in tumor progression and immune microenvironment and the crosstalk between ferroptosis and tumor immune microenvironment attracts much attention. This work summarizes the progress studies of ferroptosis in the glioma immune microenvironment.

Regulatory significance of CULLIN2 in neuronal differentiation and regeneration

BACKGROUND

Scaffold proteins coordinate multiple signalling pathways by integrating various proteins but the role of these proteins in neuronal pathways remains to be elucidated. The present study focused to evaluate the expression of the scaffold protein CULLIN2 in neuronal cells.

METHODS

The neuronal precursor cell line N2A was differentiated to neurons in-vitro with retinoic acid and biochemical assays were used to understand the gene expression profiling of CULLIN2. Moreover, neddylation inhibitor MLN4924 was used to inhibit the activity of CULLIN2 and the downstream substrates were validated. Finally, the role of CULLIN2 in nerve regeneration was evaluated in an in vivo zebrafish model.

RESULTS

Experimental data showed that the neuronal cells N2A have lower expression of CULLIN2 compared to skin cell lines (HaCaT and A431) and inactivation with the neddylation inhibitor resulted in cell death. Furthermore differentiating the neural precursor cell line into neurons with retinoic acid enhanced the expression of CULLIN2. Examining downstream signalling molecules with the neddylation inhibitor illuminates that MLN4924 treatment influences the cytokine signalling cascade (JAK-STAT) in neuronal cells. Moreover, for the first time, we show that the ubiquitin ligase protein CULLIN2 is perturbed in neural regeneration. Expression profile of CULLIN2 was significantly decreased in response to a nerve injury in Zebra fish and as the nerve regenerates there is corresponding reduction in the mRNA levels.

CONCLUSION

During differentiation CULLIN2 is upregulated whereas during regeneration there is significant downregulation. Thus, our findings reveal a crucial role of the scaffold protein CULLIN2 in nerve differentiation and regeneration which can be vital for the treatment of nerve injury.

ID2 and HIF-1α collaborate to protect quiescent hematopoietic stem cells from activation, differentiation, and exhaustion

Defining mechanism(s) that maintain tissue stem quiescence is important for improving tissue regeneration, cell therapies, aging, and cancer. We report here that genetic ablation of Id2 in adult hematopoietic stem cells (HSCs) promotes increased HSC activation and differentiation, which results in HSC exhaustion and bone marrow failure over time. Id2^Δ/Δ HSCs showed increased cycling, ROS production, mitochondrial activation, ATP production, and DNA damage compared with Id2^+/+ HSCs, supporting the conclusion that Id2^Δ/Δ HSCs are less quiescent. Mechanistically, HIF-1α expression was decreased in Id2^Δ/Δ HSCs, and stabilization of HIF-1α in Id2^Δ/Δ HSCs restored HSC quiescence and rescued HSC exhaustion. Inhibitor of DNA binding 2 (ID2) promoted HIF-1α expression by binding to the von Hippel-Lindau (VHL) protein and interfering with proteasomal degradation of HIF-1α. HIF-1α promoted Id2 expression and enforced a positive feedback loop between ID2 and HIF-1α to maintain HSC quiescence. Thus, sustained ID2 expression could protect HSCs during stress and improve HSC expansion for gene editing and cell therapies.

MiR-1248: a new prognostic biomarker able to identify supratentorial hemispheric pediatric low-grade gliomas patients associated with progression

Background

Pediatric low-grade gliomas (pLGGs), particularly incompletely resected supratentorial tumours, can undergo progression after surgery. However to date, there are no predictive biomarkers for progression. Here, we aimed to identify pLGG-specific microRNA signatures and evaluate their value as a prognostic tool.

Methods

We identified and validated supratentorial incompletey resected pLGG-specific microRNAs in independent cohorts from four European Pediatric Neuro-Oncology Centres.

Results

These microRNAs demonstrated high accuracy in differentiating patients with or without progression. Specifically, incompletely resected supratentorial pLGGs with disease progression showed significantly higher miR-1248 combined with lower miR-376a-3p and miR-888-5p levels than tumours without progression. A significant (p < 0.001) prognostic performance for miR-1248 was reported with an area under the curve (AUC) of 1.00. We also highlighted a critical oncogenic role for miR-1248 in gliomas tumours. Indeed, high miR-1248 levels maintain low its validated target genes (CDKN1A (p21)/FRK/SPOP/VHL/MTAP) and consequently sustain the activation of oncogenic pathways.

Conclusions

Altogether, we provide a novel molecular biomarker able to successfully identify pLGG patients associated with disease progression that could support the clinicians in the decision-making strategy, advancing personalized medicine.

Supplementary Information

The online version contains supplementary material available at 10.1186/s40364-022-00389-x.

DYRK1A reinforces epithelial-mesenchymal transition and metastasis of hepatocellular carcinoma via cooperatively activating STAT3 and SMAD

Background

Hepatocellular carcinoma (HCC) accounts for the majority of liver cancer cases, while metastasis is considered the leading cause of HCC-related death. However, the currently available treatment strategies for efficient suppression of metastasis are limited. Therefore, novel therapeutic targets to inhibit metastasis and effectively treat HCC are urgently required.

Methods

Wound healing and Transwell assays were used to determine the migration and invasion abilities of HCC cells in vitro. Quantitative real-time PCR (qRT-PCR), protein array, immunofluorescence, and immunoprecipitation experiments were used to study the mechanism of DYRK1A-mediated metastasis. A tail vein metastasis model and H&E staining were utilized to assess metastatic potential in vivo.

Results

The results of the current study demonstrated that dual-specificity tyrosine phosphorylation-regulated kinase 1A (DYRK1A) was upregulated in HCC tissues compared with normal liver tissues. Additionally, the level of DYRK1A was increased in primary HCC tissues of patients with metastasis compared with those of patients without metastasis, and DYRK1A overexpression correlated with worse outcomes in liver cancer patients. Gain- and loss-of-function studies suggested that DYRK1A enhanced the invasion and migration abilities of HCC cells by promoting epithelial-mesenchymal transition (EMT). Regarding the promoting effect of DYRK1A on cell invasion, the results showed that DYRK1A was coexpressed with TGF-β/SMAD and STAT3 signalling components in clinical tumour samples obtained from patients with HCC. DYRK1A also activated TGF-β/SMAD signalling by interacting with tuberous sclerosis 1 (TSC1) and enhanced metastasis of HCC cells by activating STAT3. Furthermore, DYRK1A promoted EMT by cooperatively activating STAT3/SMAD signalling.

Conclusion

Overall, the present study not only uncovered the promoting effect of DYRK1A on HCC metastasis and revealed the mechanism but also provided a new approach to predict and treat metastatic HCC.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12929-022-00817-y.

Efficacy and safety of angiogenesis inhibitors in melanoma: a meta-analysis of seven randomized controlled trials

Little is known about the efficacy and safety of angiogenesis inhibitor therapy in patients with melanoma. The objective of this study was to assess the possible benefits and harms of angiogenesis inhibitor therapy in patients with melanoma. Electronic databases of PubMed and Web of Science were searched from inception to January 2020. Randomized controlled trials (RCTs) that investigated the efficacy and safety of angiogenesis inhibitor therapy in patients with melanoma were included. Primary outcomes were overall survival (OS) and progression-free survival (PFS), reported as hazard ratios (HRs). Secondary outcomes were disease control, objective response, and adverse events, reported as odds ratios (ORs), and trial sequential analysis (TSA) was also performed. We identified seven trials with 3185 patients. There was no significant difference in OS [HR, 0.99; 95% confidence interval (CI), 0.90-1.09] or PFS (HR, 0.91; 95% CI, 0.83-1.00) between the treatment groups. No significant effect of angiogenesis inhibitor therapy was identified on disease control (OR, 1.23; 95% CI, 0.97-1.55) or objective response (OR, 1.27; 95% CI, 0.99-1.62). TSA showed that the sample size for analysis of disease control was sufficient. Additionally, angiogenesis inhibitor therapy increased risks of hypertension, neurological symptoms, and diarrhea. Angiogenesis inhibitor therapy makes no significant improvement in OS or PFS in patients with melanoma and even causes an increased risk of important adverse events. Therefore, angiogenesis inhibitor therapy is not recommended for the treatment of melanoma.

Protein phosphorylation: A potential target in glioma development

Glioma is one of the most common primary brain tumors, and mortality due to this disease is second only to cardiovascular and cerebrovascular diseases. In traditional surgery, it is difficult to eradicate glioma; often recurrence increases its malignant degree, leading to a large number of patients killed by this disease. It is one of the most important subjects to study its pathogenesis and explore effective treatment methods. Research on glioma mechanisms mainly focuses on the effect of DNA methylation in epigenetics. Although there are many studies on protein phosphorylation, there is no overall regulatory mechanism. Protein phosphorylation regulates a variety of cell functions, such as cell growth, division and differentiation, and apoptosis. As a consequence, protein phosphorylation plays a leading part in various activities of glioma, and can also be used as a target to regulate the development of glioma. This review is aimed at studying the effect of protein phosphorylation on glioma, understanding the pathological mechanism, and an in-depth analysis of it. The following is a discussion on glioma growth, migration and invasion, resistance and death in phosphorylation, and the possibility of treating glioma by phosphorylation.

Regulated interaction of ID2 with the anaphase-promoting complex links progression through mitosis with reactivation of cell-type-specific transcription

Tissue-specific transcriptional activity is silenced in mitotic cells but it remains unclear whether the mitotic regulatory machinery interacts with tissue-specific transcriptional programs. We show that such cross-talk involves the controlled interaction between core subunits of the anaphase-promoting complex (APC) and the ID2 substrate. The N-terminus of ID2 is independently and structurally compatible with a pocket composed of core APC/C subunits that may optimally orient ID2 onto the APCCDH1 complex. Phosphorylation of serine-5 by CDK1 prevented the association of ID2 with core APC, impaired ubiquitylation and stabilized ID2 protein at the mitosis-G1 transition leading to inhibition of basic Helix-Loop-Helix (bHLH)-mediated transcription. The serine-5 phospho-mimetic mutant of ID2 that inefficiently bound core APC remained stable during mitosis, delayed exit from mitosis and reloading of bHLH transcription factors on chromatin. It also locked cells into a "mitotic stem cell" transcriptional state resembling the pluripotent program of embryonic stem cells. The substrates of APCCDH1 SKP2 and Cyclin B1 share with ID2 the phosphorylation-dependent, D-box-independent interaction with core APC. These results reveal a new layer of control of the mechanism by which substrates are recognized by APC.

Selective Macrocyclic Inhibitors of DYRK1A/B

Dual-specificity tyrosine-(Y)-phosphorylation regulated kinase 1A (DYRK1A) is a therapeutic target of interest due to the roles it plays in both neurological diseases and cancer. We present the development of the first macrocyclic inhibitors of DYRK1A. Initial lead inhibitor JH-XIV-68-3 (3) displayed selectivity for DYRK1A and close family member DYRK1B in biochemical and cellular assays, and demonstrated antitumor efficacy in head and neck squamous cell carcinoma (HNSCC) cell lines. However, we noted that it suffered from rapid aldehyde oxidase (AO)-mediated metabolism. To overcome this liability, we generated a derivative (JH-XVII-10 (10)), where fluorine was introduced to block the 2-position of the azaindole and render the molecule resistant to AO activity. We showed that 10 maintains remarkable potency and selectivity in biochemical and cellular assays as well as antitumor efficacy in HNSCC cell lines and improved metabolic stability. Therefore, 10 represents a promising new scaffold for developing DYRK1A-targeting chemical probes and therapeutics.

The chromosome 21 kinase DYRK1A: emerging roles in cancer biology and potential as a therapeutic target

Dual-specificity tyrosine phosphorylation-regulated kinase 1 A (DYRK1A) is a serine/threonine kinase that belongs to the DYRK family of proteins, a subgroup of the evolutionarily conserved CMGC protein kinase superfamily. Due to its localization on chromosome 21, the biological significance of DYRK1A was initially characterized in the pathogenesis of Down syndrome (DS) and related neurodegenerative diseases. However, increasing evidence has demonstrated a prominent role in cancer through its ability to regulate biologic processes including cell cycle progression, DNA damage repair, transcription, ubiquitination, tyrosine kinase activity, and cancer stem cell maintenance. DYRK1A has been identified as both an oncogene and tumor suppressor in different models, underscoring the importance of cellular context in its function. Here, we review mechanistic contributions of DYRK1A to cancer biology and its role as a potential therapeutic target.

DYRK1A suppression attenuates HIF‑1α accumulation and enhances the anti‑liver cancer effects of regorafenib and sorafenib under hypoxic conditions

Hypoxia promotes drug resistance and induces the expression of hypoxia inducible factor (HIF)‑1α in liver cancer cells. However, to date, no selective HIF‑1α inhibitor has been clinically approved. The aim of this study is to investigate a drug‑targetable molecule that can regulate HIF‑1α under hypoxia. The present study demonstrated that hyperactivation of dual‑specificity tyrosine‑phosphorylation‑regulated kinase 1A (DYRK1A)/HIF‑1α signaling was associated with an increased risk of liver cancer. In addition, DYRK1A knockdown using small interfering RNA transfection or treatment with harmine, a natural alkaloid, significantly reduced the protein expression levels of HIF‑1α in liver cancer cells under hypoxic conditions in vitro. Conversely, DYRK1A overexpression‑vector transfection in liver cancer cell lines notably induced HIF‑1α expression under the same conditions. Furthermore, DYRK1A was shown to interact and activate STAT3 under hypoxia to regulate HIF‑1α expression. These findings indicated that DYRK1A may be a potential upstream activator of HIF‑1α and positively regulate HIF‑1α via the STAT3 signaling pathway in liver cancer cells. Additionally, treatment with harmine attenuated the proliferative ability of liver cancer cells under hypoxic conditions using sulforhodamine B and colony formation assay. Furthermore, DYRK1A knockdown could significantly enhance the anti‑liver cancer effects of regorafenib and sorafenib under hypoxia. Co‑treatment with harmine and either regorafenib or sorafenib also promoted cell death via the STAT3/HIF‑1α/AKT signaling pathway under hypoxia using PI staining and western blotting. Overall, the results from the present study suggested that DYRK1A/HIF‑1α signaling may be considered a novel pathway involved in chemoresistance, thus providing a potentially effective therapeutic regimen for treating liver cancer.

USP33 deubiquitinates and stabilizes HIF-2alpha to promote hypoxia response in glioma stem cells

Hypoxia regulates tumor angiogenesis, metabolism, and therapeutic response in malignant cancers including glioblastoma, the most lethal primary brain tumor. The regulation of HIF transcriptional factors by the ubiquitin-proteasome system is critical in the hypoxia response, but hypoxia-inducible deubiquitinases that counteract the ubiquitination remain poorly defined. While the activation of ERK1/2 also plays an important role in hypoxia response, the relationship between ERK1/2 activation and HIF regulation remains elusive. Here, we identified USP33 as essential deubiquitinase that stabilizes HIF-2alpha protein in an ERK1/2-dependent manner to promote hypoxia response in cancer cells. USP33 is preferentially induced in glioma stem cells by hypoxia and interacts with HIF-2alpha, leading to its stabilization through deubiquitination. The activation of ERK1/2 upon hypoxia promoted HIF-2alpha phosphorylation, enhancing its interaction with USP33. Silencing of USP33 disrupted glioma stem cells maintenance, reduced tumor vascularization, and inhibited glioblastoma growth. Our findings highlight USP33 as an essential regulator of hypoxia response in cancer stem cells, indicating a novel potential therapeutic target for brain tumor treatment.

ASCL1 phosphorylation and ID2 upregulation are roadblocks to glioblastoma stem cell differentiation

The growth of glioblastoma (GBM), one of the deadliest adult cancers, is fuelled by a subpopulation of stem/progenitor cells, which are thought to be the source of resistance and relapse after treatment. Re-engagement of a latent capacity of these cells to re-enter a trajectory resulting in cell differentiation is a potential new therapeutic approach for this devastating disease. ASCL1, a proneural transcription factor, plays a key role in normal brain development and is also expressed in a subset of GBM cells, but fails to engage a full differentiation programme in this context. Here, we investigated the barriers to ASCL1-driven differentiation in GBM stem cells. We see that ASCL1 is highly phosphorylated in GBM stem cells where its expression is compatible with cell proliferation. However, overexpression of a form of ASCL1 that cannot be phosphorylated on Serine–Proline sites drives GBM cells down a neuronal lineage and out of cell cycle more efficiently than its wild-type counterpart, an effect further enhanced by deletion of the inhibitor of differentiation ID2, indicating mechanisms to reverse the block to GBM cell differentiation.

HIF1α/HIF2α induces glioma cell dedifferentiation into cancer stem cells through Sox2 under hypoxic conditions

Objective: Our previous study showed that glioma stem-like cells could be induced to undergo dedifferentiation under hypoxic conditions, but the mechanism requires further study. HIF1α and HIF2α are the main molecules involved in the response to hypoxia, and Sox2, as a retroelement, plays an important role in the formation of induced pluripotent stem cells, especially in hypoxic microenvironments. Therefore, we performed a series of experiments to verify whether HIF1α, HIF2α and Sox2 regulated glioma cell dedifferentiation under hypoxic conditions.

Materials and methods: Sphere formation by single glioma cells was observed, and CD133 and CD15 expression was compared between the normoxic and hypoxic groups. HIF1α, HIF2α, and Sox2 expression was detected using the CGGA database, and the correlation among HIF1α, HIF2α and Sox2 levels was analyzed. We knocked out HIF1α, HIF2α and Sox2 in glioma cells and cultured them under hypoxic conditions to detect CD133 and CD15 expression. The above cells were implanted into mouse brains to analyze tumor volume and survival time.

Results: New spheres were formed from single glioma cells in 1% O₂, but no spheres were formed in 21% O₂. The cells cultured in 1% O₂ highly expressed CD133 and CD15 and had a lower apoptosis rate. The CGGA database showed HIF1α and HIF2α expression in glioma. Knocking out HIF1α or HIF2α led to a decrease in CD133 and CD15 expression and inhibited sphere formation under hypoxic conditions. Moreover, tumor volume and weight decreased after HIF1α or HIF2α knockout with the same temozolomide treatment. Sox2 was also highly expressed in glioma, and there was a positive correlation between the HIF1α/HIF2α and Sox2 expression levels. Sox2 was expressed at lower levels after HIF1α or HIF2α was knocked out. Then, Sox2 was knocked out, and we found that CD133 and CD15 expression was decreased. Moreover, a lower sphere formation rate, higher apoptosis rate, lower tumor formation rate and longer survival time after temozolomide treatment were detected in the Sox2 knockout cells.

Conclusion: In a hypoxic microenvironment, the HIF1α/HIF2α-Sox2 network induced the formation of glioma stem cells through the dedifferentiation of differentiated glioma cells, thus promoting glioma cell chemoresistance. This study demonstrates that both HIF1α and HIF2α, as genes upstream of Sox2, regulate the malignant progression of glioma through dedifferentiation.

USP1 Promotes GC Metastasis via Stabilizing ID2

Gastric cancer (GC) is one of the most common malignant tumors all over the world. And recurrence and metastasis are still the main causes of low survival rate for advanced GC. USP1 has been shown overexpressed in multiple cancers, which indicate its important biomarker in tumorigenesis and development. Our study is aimed at defining the exact role of USP1 on GC metastasis and the underlying mechanism. USP1 was firstly found overexpressed in GC tissues and relatively high-expression levels conferred poor survival rates. Then, real-time cellular analysis (RTCA) showed that USP1 knockdown inhibited GC metastasis both in vitro and in vivo. Mechanically, we demonstrated that USP1 promoted GC metastasis via upregulating ID2 expression and further confirmed that USP1 stabilized ID2 expression through deubiquitinating ID2 in GC. In conclusion, our study showed that USP1 promoted GC metastasis via stabilizing ID2 expression, which provides a potential biomarker and therapy target for GC.

DYRK1A is required for maintenance of cancer stemness, contributing to tumorigenic potential in oral/oropharyngeal squamous cell carcinoma

DYRK1A, one of the dual-specificity tyrosine phosphorylation-regulated kinases (DYRKs), plays an important role in various biological processes by regulating downstream targets via kinase-dependent and independent mechanisms. Here, we report a novel role of DYRK1A in maintaining tumor growth and stemness of oral/oropharyngeal squamous cell carcinoma (OSCC) cells. Deletion of DYRK1A from OSCC cells abrogated their in vivo tumorigenicity and self-renewal capacity, the key features of cancer stem-like cells (CSCs; also referred to as tumor-initiating cells). The DYRK1A deletion also induced the suppression of CSC populations and properties, such as migration ability and chemoresistance. Conversely, ectopic expression of DYRK1A in OSCC cells augmented their CSC phenotype. Among five DYRK members (DYRK1A, 1B, 2, 3, and 4), DYRK1A is the most dominantly expressed kinase, and its expression is upregulated in OSCC compared to normal oral epithelial cells. More importantly, DYRK1A was highly enriched in various CSC-enriched OSCC populations compared to their corresponding non-CSC populations, indicating its pivotal role in cancer progression and stemness. Further, our study revealed that fibroblast growth factor 2 (FGF2) is a key regulator in the DYRK1A-mediated CSC regulation. Functional studies demonstrated that the loss of DYRK1A inhibits CSC phenotype via reduction of FGF2. Overexpression of DYRK1A promotes CSC phenotype via upregulation of FGF2. Our study delineates a novel mechanism of cancer stemness regulation by DYRK1A-FGF2 axis in OSCC. Thus, inhibition of DYRK1A would lead to a potential novel therapeutic option for targeting CSCs in OSCC.

DYRK1A phosphorylates MEF2D and decreases its transcriptional activity

Myocyte enhancer factor 2D (MEF2D) is predominantly expressed in the nucleus and associated with cell growth, differentiation, survival and apoptosis. Previous studies verified that phosphorylation at different amino acids determined MEF2's transcriptional activity which was essential in regulating downstream target genes expression. What regulates phosphorylation of MEF2D and affects its function has not been fully elucidated. Here, we uncovered that dual-specificity tyrosine phosphorylation regulated kinase 1A (DYRK1A), a kinase critical in Down's syndrome pathogenesis, directly bound to and phosphorylated MEF2D at Ser251 in vitro. Phosphorylation of MEF2D by DYRK1A significantly increased MEF2D protein level but attenuated its transcriptional activity, which resulted in decreased transcriptions of MEF2D target genes. Phosphorylation mutated Ser251A MEF2D exhibited enhanced transcriptional activity compared with wild type MEF2D. MEF2D and DYRK1A were observed co-localized in HEK293 and U87MG cells. Moreover, DYRK1A-mediated MEF2D phosphorylation in vitro might influence its nuclear export upon subcellular fractionation, which partially explained the reduction of MEF2D transcriptional activity by DYRK1A. Our results indicated that DYRK1A might be a regulator of MEF2D transcriptional activity and indirectly get involved in regulation of MEF2D target genes.

Molecular Insights into the Oxygen-Sensing Pathway and Erythropoietin Expression Regulation in Erythropoiesis

Erythropoiesis is regulated by several factors, including the oxygen-sensing pathway as the main regulator of erythropoietin (EPO) synthesis in the kidney. The release of EPO from the kidney and its binding to the EPO receptor (EPOR) on erythrocyte progenitor cells in the bone marrow results in increased erythropoiesis. Any imbalance in these homeostatic mechanisms can lead to dysregulated erythropoiesis and hematological disorders. For example, mutations in genes encoding key players of oxygen-sensing pathway and regulation of EPO production (HIF-EPO pathway), namely VHL, EGLN, EPAS1 and EPO, are well known causative factors that contribute to the development of erythrocytosis. We aimed to investigate additional molecular mechanisms involved in the HIF-EPO pathway that correlate with erythropoiesis. To this end, we conducted an extensive literature search and used several in silico tools. We identified genes encoding transcription factors and proteins that control transcriptional activation or repression; genes encoding kinases, deacetylases, methyltransferases, conjugating enzymes, protein ligases, and proteases involved in post-translational modifications; and genes encoding nuclear transport receptors that regulate nuclear transport. All these genes may modulate the stability or activity of HIF2α and its partners in the HIF-EPO pathway, thus affecting EPO synthesis. The theoretical information we provide in this work can be a valuable tool for a better understanding of one of the most important regulatory pathways in the process of erythropoiesis. This knowledge is necessary to discover the causative factors that may contribute to the development of hematological diseases and improve current diagnostic and treatment solutions in this regard.

DYRK3 contributes to differentiation and hypoxic control in neuroblastoma

Neuroblastoma (NB), a pediatric cancer of the peripheral sympathetic nervous system, represents the most frequent solid malignancy in infants. Treatment of high-risk patients is still challenging and, depending on the genetic make-up and involved risk factors, the 5-year survival rate can drop to only 30%. Here, we found that the expression of the Dual Specificity Tyrosine Phosphorylation Regulated Kinase 3 (DYRK3) is increased in NB and is associated with decreased survival in NB patients. We further identified DYRK3 as a cytoplasmic kinase in NB cells and found that its levels are increased by hypoxic conditions. Further mechanistic studies revealed that DYRK3 acts as a negative regulator of HIF-driven transcriptional responses, suggesting that it functions in a negative feedback loop controlling the hypoxic response. Moreover, DYRK3 negatively impacted on NB cell differentiation, proposing an oncogenic role of this kinase in the etiology of NB. In summary, we describe novel functions of the DYRK3 kinase in NB, which will help to further improve the understanding of this disease eventually leading to the design of improved therapeutic concepts.

Dual-Specificity, Tyrosine Phosphorylation-Regulated Kinases (DYRKs) and cdc2-Like Kinases (CLKs) in Human Disease, an Overview

Dual-specificity tyrosine phosphorylation-regulated kinases (DYRK1A, 1B, 2-4) and cdc2-like kinases (CLK1-4) belong to the CMGC group of serine/threonine kinases. These protein kinases are involved in multiple cellular functions, including intracellular signaling, mRNA splicing, chromatin transcription, DNA damage repair, cell survival, cell cycle control, differentiation, homocysteine/methionine/folate regulation, body temperature regulation, endocytosis, neuronal development, synaptic plasticity, etc. Abnormal expression and/or activity of some of these kinases, DYRK1A in particular, is seen in many human nervous system diseases, such as cognitive deficits associated with Down syndrome, Alzheimer's disease and related diseases, tauopathies, dementia, Pick's disease, Parkinson's disease and other neurodegenerative diseases, Phelan-McDermid syndrome, autism, and CDKL5 deficiency disorder. DYRKs and CLKs are also involved in diabetes, abnormal folate/methionine metabolism, osteoarthritis, several solid cancers (glioblastoma, breast, and pancreatic cancers) and leukemias (acute lymphoblastic leukemia, acute megakaryoblastic leukemia), viral infections (influenza, HIV-1, HCMV, HCV, CMV, HPV), as well as infections caused by unicellular parasites (Leishmania, Trypanosoma, Plasmodium). This variety of pathological implications calls for (1) a better understanding of the regulations and substrates of DYRKs and CLKs and (2) the development of potent and selective inhibitors of these kinases and their evaluation as therapeutic drugs. This article briefly reviews the current knowledge about DYRK/CLK kinases and their implications in human disease.

Anti-tumor effects of an ID antagonist with no observed acquired resistance

ID proteins are helix-loop-helix (HLH) transcriptional regulators frequently overexpressed in cancer. ID proteins inhibit basic-HLH transcription factors often blocking differentiation and sustaining proliferation. A small-molecule, AGX51, targets ID proteins for degradation and impairs ocular neovascularization in mouse models. Here we show that AGX51 treatment of cancer cell lines impairs cell growth and viability that results from an increase in reactive oxygen species (ROS) production upon ID degradation. In mouse models, AGX51 treatment suppresses breast cancer colonization in the lung, regresses the growth of paclitaxel-resistant breast tumors when combined with paclitaxel and reduces tumor burden in sporadic colorectal neoplasia. Furthermore, in cells and mice, we fail to observe acquired resistance to AGX51 likely the result of the inability to mutate the binding pocket without loss of ID function and efficient degradation of the ID proteins. Thus, AGX51 is a first-in-class compound that antagonizes ID proteins, shows strong anti-tumor effects and may be further developed for the management of multiple cancers.

Role of Hypoxia in the Control of the Cell Cycle

The cell cycle is an important cellular process whereby the cell attempts to replicate its genome in an error-free manner. As such, mechanisms must exist for the cell cycle to respond to stress signals such as those elicited by hypoxia or reduced oxygen availability. This review focuses on the role of transcriptional and post-transcriptional mechanisms initiated in hypoxia that interface with cell cycle control. In addition, we discuss how the cell cycle can alter the hypoxia response. Overall, the cellular response to hypoxia and the cell cycle are linked through a variety of mechanisms, allowing cells to respond to hypoxia in a manner that ensures survival and minimal errors throughout cell division.

The non-canonical functions of HIF prolyl hydroxylases and their dual roles in cancer

The hypoxia-inducible factor (HIF) prolyl hydroxylases (PHDs) are dioxygenases using oxygen and 2-oxoglutarate as co-substrates. Under normoxia, PHDs hydroxylate the conserved prolyl residues of HIFα, leading to HIFα degradation. In hypoxia PHDs are inactivated, which results in HIFα accumulation. The accumulated HIFα enters nucleus and initiates gene transcription. Many studies have shown that PHDs have substrates other than HIFα, implying that they have HIF-independent non-canonical functions. Besides modulating protein stability, the PHDs-mediated prolyl hydroxylation affects protein-protein interaction and protein activity for alternative substrates. Increasing evidence indicates that PHDs also have hydroxylase-independent functions. They influence protein stability, enzyme activity, and protein-protein interaction in a hydroxylase-independent manner. These findings highlight the functional diversity and complexity of PHDs. Due to having inhibitory activity on HIFα, PHDs are proposed to act as tumor suppressors. However, research shows that PHDs exert either tumor-promoting or tumor-suppressing features. Here, we try to summarize the current understanding of PHDs hydroxylase-dependent and -independent functions and their roles in cancer.

Global phosphoproteomics reveals DYRK1A regulates CDK1 activity in glioblastoma cells

Both tumour suppressive and oncogenic functions have been reported for dual-specificity tyrosine phosphorylation-regulated kinase 1A (DYRK1A). Herein, we performed a detailed investigation to delineate the role of DYRK1A in glioblastoma. Our phosphoproteomic and mechanistic studies show that DYRK1A induces degradation of cyclin B by phosphorylating CDC23, which is necessary for the function of the anaphase-promoting complex, a ubiquitin ligase that degrades mitotic proteins. DYRK1A inhibition leads to the accumulation of cyclin B and activation of CDK1. Importantly, we established that the phenotypic response of glioblastoma cells to DYRK1A inhibition depends on both retinoblastoma (RB) expression and the degree of residual DYRK1A activity. Moderate DYRK1A inhibition leads to moderate cyclin B accumulation, CDK1 activation and increased proliferation in RB-deficient cells. In RB-proficient cells, cyclin B/CDK1 activation in response to DYRK1A inhibition is neutralized by the RB pathway, resulting in an unchanged proliferation rate. In contrast, complete DYRK1A inhibition with high doses of inhibitors results in massive cyclin B accumulation, saturation of CDK1 activity and cell cycle arrest, regardless of RB status. These findings provide new insights into the complexity of context-dependent DYRK1A signalling in cancer cells.

DYRK1A Negatively Regulates CDK5-SOX2 Pathway and Self-Renewal of Glioblastoma Stem Cells

Glioblastoma display vast cellular heterogeneity, with glioblastoma stem cells (GSCs) at the apex. The critical role of GSCs in tumour growth and resistance to therapy highlights the need to delineate mechanisms that control stemness and differentiation potential of GSC. Dual-specificity tyrosine phosphorylation-regulated kinase 1A (DYRK1A) regulates neural progenitor cell differentiation, but its role in cancer stem cell differentiation is largely unknown. Herein, we demonstrate that DYRK1A kinase is crucial for the differentiation commitment of glioblastoma stem cells. DYRK1A inhibition insulates the self-renewing population of GSCs from potent differentiation-inducing signals. Mechanistically, we show that DYRK1A promotes differentiation and limits stemness acquisition via deactivation of CDK5, an unconventional kinase recently described as an oncogene. DYRK1A-dependent inactivation of CDK5 results in decreased expression of the stemness gene SOX2 and promotes the commitment of GSC to differentiate. Our investigations of the novel DYRK1A-CDK5-SOX2 pathway provide further insights into the mechanisms underlying glioblastoma stem cell maintenance.

Identification of Hub Genes and Key Pathways Associated with Anti-VEGF Resistant Glioblastoma Using Gene Expression Data Analysis

Anti-VEGF therapy is considered to be a useful therapeutic approach in many tumors, but the low efficacy and drug resistance limit its therapeutic potential and promote tumor growth through alternative mechanisms. We reanalyzed the gene expression data of xenografts of tumors of bevacizumab-resistant glioblastoma multiforme (GBM) patients, using bioinformatics tools, to understand the molecular mechanisms of this resistance. An analysis of the gene set data from three generations of xenografts, identified as 646, 873 and 1220, differentially expressed genes (DEGs) in the first, fourth and ninth generations, respectively, of the anti-VEGF-resistant GBM cells. Gene Ontology (GO) and pathway enrichment analyses demonstrated that the DEGs were significantly enriched in biological processes such as angiogenesis, cell proliferation, cell migration, and apoptosis. The protein–protein interaction network and module analysis revealed 21 hub genes, which were enriched in cancer pathways, the cell cycle, the HIF1 signaling pathway, and microRNAs in cancer. The VEGF pathway analysis revealed nine upregulated (IL6, EGFR, VEGFA, SRC, CXCL8, PTGS2, IDH1, APP, and SQSTM1) and five downregulated hub genes (POLR2H, RPS3, UBA52, CCNB1, and UBE2C) linked with several of the VEGF signaling pathway components. The survival analysis showed that three upregulated hub genes (CXCL8, VEGFA, and IDH1) were associated with poor survival. The results predict that these hub genes associated with the GBM resistance to bevacizumab may be potential therapeutic targets or can be biomarkers of the anti-VEGF resistance of GBM.

Pathway-based classification of glioblastoma uncovers a mitochondrial subtype with therapeutic vulnerabilities

The transcriptomic classification of glioblastoma (GBM) has failed to predict survival and therapeutic vulnerabilities. A computational approach for unbiased identification of core biological traits of single cells and bulk tumors uncovered four tumor cell states and GBM subtypes distributed along neurodevelopmental and metabolic axes, classified as proliferative/progenitor, neuronal, mitochondrial and glycolytic/plurimetabolic. Each subtype was enriched with biologically coherent multiomic features. Mitochondrial GBM was associated with the most favorable clinical outcome. It relied exclusively on oxidative phosphorylation for energy production, whereas the glycolytic/plurimetabolic subtype was sustained by aerobic glycolysis and amino acid and lipid metabolism. Deletion of the glucose-proton symporter SLC45A1 was the truncal alteration most significantly associated with mitochondrial GBM, and the reintroduction of SLC45A1 in mitochondrial glioma cells induced acidification and loss of fitness. Mitochondrial, but not glycolytic/plurimetabolic, GBM exhibited marked vulnerability to inhibitors of oxidative phosphorylation. The pathway-based classification of GBM informs survival and enables precision targeting of cancer metabolism.

Phosphorylation regulates cullin-based ubiquitination in tumorigenesis

Cullin-RING ligases (CRLs) recognize and interact with substrates for ubiquitination and degradation, and can be targeted for disease treatment when the abnormal expression of substrates involves pathologic processes. Phosphorylation, either of substrates or receptors of CRLs, can alter their interaction. Phosphorylation-dependent ubiquitination and proteasome degradation influence various cellular processes and can contribute to the occurrence of various diseases, most often tumorigenesis. These processes have the potential to be used for tumor intervention through the regulation of the activities of related kinases, along with the regulation of the stability of specific oncoproteins and tumor suppressors. This review describes the mechanisms and biological functions of crosstalk between phosphorylation and ubiquitination, and most importantly its influence on tumorigenesis, to provide new directions and strategies for tumor therapy.

An Assessment of InP/ZnS as Potential Anti-Cancer Therapy: Quantum Dot Treatment Increases Apoptosis in HeLa Cells

InP/ZnS quantum dots (QDs) are an emerging option in QD technologies for uses of fluorescent imaging as well as targeted drug and anticancer therapies based on their customizable properties. In this study we explored effects of InP/ZnS when treated with HeLa cervical cancer cells. We employed XTT viability assays, reactive oxygen species (ROS) analysis, and apoptosis analysis to better understand cytotoxicity extents at different concentrations of InP/ZnS. In addition, we compared the transcriptome profile from the QD-treated HeLa cells with that of untreated HeLa cells to identify changes to the transcriptome in response to the QD. RT-qPCR assay was performed to confirm the findings of transcriptome analysis, and the QD mode of action was illustrated. Our study determined both IC50 concentration of 69 µg/mL and MIC concentration of 167 µg/mL of InP/ZnS. It was observed via XTT assay that cell viability was decreased significantly at the MIC. Production of superoxide, measured by ROS assay with flow cytometry, was decreased, whereas levels of nitrogen radicals increased. Using analysis of apoptosis, we found that induced cell death in the QD-treated samples was shown to be significantly increased when compared to untreated cells. We conclude InP/ZnS QD to decrease cell viability by inducing stress via ROS levels, apoptosis induction, and alteration of transcriptome.

DYRK1A regulates B cell acute lymphoblastic leukemia through phosphorylation of FOXO1 and STAT3

DYRK1A is a serine/threonine kinase encoded on human chromosome 21 (HSA21) that has been implicated in several pathologies of Down syndrome (DS), including cognitive deficits and Alzheimer's disease. Although children with DS are predisposed to developing leukemia, especially B cell acute lymphoblastic leukemia (B-ALL), the HSA21 genes that contribute to malignancies remain largely undefined. Here, we report that DYRK1A is overexpressed and required for B-ALL. Genetic and pharmacologic inhibition of DYRK1A decreased leukemic cell expansion and suppressed B-ALL development in vitro and in vivo. Furthermore, we found that FOXO1 and STAT3, transcription factors that are indispensable for B cell development, are critical substrates of DYRK1A. Loss of DYRK1A-mediated FOXO1 and STAT3 signaling disrupted DNA damage and ROS regulation, respectively, leading to preferential cell death in leukemic B cells. Thus, we reveal a DYRK1A/FOXO1/STAT3 axis that facilitates the development and maintenance of B-ALL.

Glioma stem cells and their roles within the hypoxic tumor microenvironment

Tumor microenvironments are the result of cellular alterations in cancer that support unrestricted growth and proliferation and result in further modifications in cell behavior, which are critical for tumor progression. Angiogenesis and therapeutic resistance are known to be modulated by hypoxia and other tumor microenvironments, such as acidic stress, both of which are core features of the glioblastoma microenvironment. Hypoxia has also been shown to promote a stem-like state in both non-neoplastic and tumor cells. In glial tumors, glioma stem cells (GSCs) are central in tumor growth, angiogenesis, and therapeutic resistance, and further investigation of the interplay between tumor microenvironments and GSCs is critical to the search for better treatment options for glioblastoma. Accordingly, we summarize the impact of hypoxia and acidic stress on GSC signaling and biologic phenotypes, and potential methods to inhibit these pathways.

A Novel TGF-β Risk Score Predicts the Clinical Outcomes and Tumour Microenvironment Phenotypes in Bladder Cancer

Background

The TGF-β pathway plays critical roles in numerous malignancies. Nevertheless, its potential role in prognosis prediction and regulating tumour microenvironment (TME) characteristics require further elucidation in bladder cancer (BLCA).

Methods

TGF-β-related genes were comprehensively summarized from several databases. The TCGA-BLCA cohort (training cohort) was downloaded from the Cancer Genome Atlas, and the independent validation cohorts were gathered from Xiangya Hospital (Xinagya cohort) and Gene Expression Omnibus. Initially, we identified differentially expressed TGF-β genes (DEGs) between cancer and normal tissues. Subsequently, univariate Cox analysis was applied to identify prognostic DEGs, which were further used to develop the TGF-β risk score by performing LASSO and multivariate Cox analyses. Then, we studied the role of the TGF-β risk score in predicting prognosis and the TME phenotypes. In addition, the role of the TGF-β risk score in guiding precision treatments for BLCA has also been assessed.

Results

We successfully constructed a TGF-β risk score with an independent prognostic prediction value. A high TGF-β risk score indicated an inflamed TME, which was supported by the positive relationships between the risk score, enrichment scores of anticancer immunity steps, and the infiltration levels of tumour-infiltrating immune cells. In addition, the risk score positively correlated with the expression of several immune checkpoints and the T cell inflamed score. Consistently, the risk score was positively related to the enrichment scores of most immunotherapy-positive pathways. In addition, the sensitivities of six common chemotherapeutic drugs were positively associated with the risk score. Furthermore, higher risk score indicated higher sensitivity to radiotherapy and EGFR-targeted therapy. On the contrary, patients with low-risk scores were more sensitive to targeted therapies, including the blockade of FGFR3 and WNT-β-catenin networks.

Conclusions

We first constructed and validated a TGF-β signature that could predict the prognosis and TME phenotypes for BLCA. More importantly, the TGF-β risk score could aid in individual precision treatment for BLCA.

Minibrain-related kinase/dual-specificity tyrosine-regulated kinase 1B implication in stem/cancer stem cells biology

Dual-specificity tyrosine phosphorylation-regulated kinase 1B (DYRK1B), also known as minibrain-related kinase (MIRK) is one of the best functionally studied members of the DYRK kinase family. DYRKs comprise a family of protein kinases that are emerging modulators of signal transduction pathways, cell proliferation and differentiation, survival, and cell motility. DYRKs were found to participate in several signaling pathways critical for development and cell homeostasis. In this review, we focus on the DYRK1B protein kinase from a functional point of view concerning the signaling pathways through which DYRK1B exerts its cell type-dependent function in a positive or negative manner, in development and human diseases. In particular, we focus on the physiological role of DYRK1B in behavior of stem cells in myogenesis, adipogenesis, spermatogenesis and neurogenesis, as well as in its pathological implication in cancer and metabolic syndrome. Thus, understanding of the molecular mechanisms that regulate signaling pathways is of high importance. Recent studies have identified a close regulatory connection between DYRK1B and the hedgehog (HH) signaling pathway. Here, we aim to bring together what is known about the functional integration and cross-talk between DYRK1B and several signaling pathways, such as HH, RAS and PI3K/mTOR/AKT, as well as how this might affect cellular and molecular processes in development, physiology, and pathology. Thus, this review summarizes the major known functions of DYRK1B kinase, as well as the mechanisms by which DYRK1B exerts its functions in development and human diseases focusing on the homeostasis of stem and cancer stem cells.

The HIF1α/HIF2α-miR210-3p network regulates glioblastoma cell proliferation, dedifferentiation and chemoresistance through EGF under hypoxic conditions

Hypoxia-inducible factor 1α (HIF1α) promotes the malignant progression of glioblastoma under hypoxic conditions, leading to a poor prognosis for patients with glioblastoma; however, none of the therapies targeting HIF1α in glioblastoma have successfully eradicated the tumour. Therefore, we focused on the reason and found that treatments targeting HIF1α and HIF2α simultaneously increased tumour volume, but the combination of HIF1α/HIF2α-targeted therapies with temozolomide (TMZ) reduced tumourigenesis and significantly improved chemosensitization. Moreover, miR-210-3p induced HIF1α expression but inhibited HIF2α expression, suggesting that miR-210-3p regulates HIF1α/HIF2α expression. Epidermal growth factor (EGF) has been shown to upregulate HIF1α expression under hypoxic conditions. However, in the present study, in addition to the signalling pathways mentioned above, the upstream proteins HIF1α and HIF2α have been shown to induce EGF expression by binding to the sequences AGGCGTGG and GGGCGTGG. Briefly, in a hypoxic microenvironment the HIF1α/HIF2α-miR210-3p network promotes the malignant progression of glioblastoma through a positive feedback loop with EGF. Additionally, differentiated glioblastoma cells underwent dedifferentiation to produce glioma stem cells under hypoxic conditions, and simultaneous knockout of HIF1α and HIF2α inhibited cell cycle arrest but promoted proliferation with decreased stemness, promoting glioblastoma cell chemosensitization. In summary, both HIF1α and HIF2α regulate glioblastoma cell proliferation, dedifferentiation and chemoresistance through a specific pathway, which is important for glioblastoma treatments.

Three-dimensional bioprinted glioblastoma microenvironments model cellular dependencies and immune interactions

Brain tumors are dynamic complex ecosystems with multiple cell types. To model the brain tumor microenvironment in a reproducible and scalable system, we developed a rapid three-dimensional (3D) bioprinting method to construct clinically relevant biomimetic tissue models. In recurrent glioblastoma, macrophages/microglia prominently contribute to the tumor mass. To parse the function of macrophages in 3D, we compared the growth of glioblastoma stem cells (GSCs) alone or with astrocytes and neural precursor cells in a hyaluronic acid-rich hydrogel, with or without macrophage. Bioprinted constructs integrating macrophage recapitulate patient-derived transcriptional profiles predictive of patient survival, maintenance of stemness, invasion, and drug resistance. Whole-genome CRISPR screening with bioprinted complex systems identified unique molecular dependencies in GSCs, relative to sphere culture. Multicellular bioprinted models serve as a scalable and physiologic platform to interrogate drug sensitivity, cellular crosstalk, invasion, context-specific functional dependencies, as well as immunologic interactions in a species-matched neural environment.

Nuclear P38: Roles in Physiological and Pathological Processes and Regulation of Nuclear Translocation

The p38 mitogen-activated protein kinase (p38MAPK, termed here p38) cascade is a central signaling pathway that transmits stress and other signals to various intracellular targets in the cytoplasm and nucleus. More than 150 substrates of p38α/β have been identified, and this number is likely to increase. The phosphorylation of these substrates initiates or regulates a large number of cellular processes including transcription, translation, RNA processing and cell cycle progression, as well as degradation and the nuclear translocation of various proteins. Being such a central signaling cascade, its dysregulation is associated with many pathologies, particularly inflammation and cancer. One of the hallmarks of p38α/β signaling is its stimulated nuclear translocation, which occurs shortly after extracellular stimulation. Although p38α/β do not contain nuclear localization or nuclear export signals, they rapidly and robustly translocate to the nucleus, and they are exported back to the cytoplasm within minutes to hours. Here, we describe the physiological and pathological roles of p38α/β phosphorylation, concentrating mainly on the ill-reviewed regulation of p38α/β substrate degradation and nuclear translocation. In addition, we provide information on the p38α/β ’s substrates, concentrating mainly on the nuclear targets and their role in p38α/β functions. Finally, we also provide information on the mechanisms of nuclear p38α/β translocation and its use as a therapeutic target for p38α/β-dependent diseases.