The Tumor Suppressor MTUS1/ATIP1 Modulates Tumor Promotion in Glioma: Association with Epigenetics and DNA Repair

Glioblastoma (GBM) is a highly aggressive brain tumor. Resistance mechanisms in GBM present an array of challenges to understand its biology and to develop novel therapeutic strategies. We investigated the role of a TSG, MTUS1/ATIP1 in glioma. Glioma specimen, cells and low passage GBM sphere cultures (GSC) were analyzed for MTUS1/ATIP1 expression at the RNA and protein level. Methylation analyses were done by bisulfite sequencing (BSS). The consequence of chemotherapy and irradiation on ATIP1 expression and the influence of different cellular ATIP1 levels on survival was examined in vitro and in vivo. MTUS1/ATIP1 was downregulated in high-grade glioma (HGG), GSC and GBM cells and hypermethylation at the ATIP1 promoter region seems to be at least partially responsible for this downregulation. ATIP1 overexpression significantly reduced glioma progression by mitigating cell motility, proliferation and facilitate cell death. In glioma-bearing mice, elevated MTUS1/ATIP1 expression prolonged their survival. Chemotherapy, as well as irradiation, recovered ATIP1 expression both in vitro and in vivo. Surprisingly, ATIP1 overexpression increased irradiation-induced DNA-damage repair, resulting in radio-resistance. Our findings indicate that MTUS1/ATIP1 serves as TSG-regulating gliomagenesis, progression and therapy resistance. In HGG, higher MTUS1/ATIP1 expression might interfere with tumor irradiation therapy.

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Multiplexed RNAi therapy against brain tumor-initiating cells via lipopolymeric nanoparticle infusion delays glioblastoma progression

Proceedings of the National Academy of Sciences ◽

10.1073/pnas.1701911114 ◽

2017 ◽

Vol 114 (30) ◽

pp. E6147-E6156 ◽

Cited By ~ 53

Author(s):

Dou Yu ◽

Omar F. Khan ◽

Mario L. Suvà ◽

Biqin Dong ◽

Wojciech K. Panek ◽

...

Keyword(s):

Brain Tumor ◽

Therapeutic Potential ◽

Therapy Resistance ◽

Tumor Initiating Cells ◽

Convection Enhanced Delivery ◽

Individual Gene ◽

Brain Tumor Initiating Cells ◽

Novel Therapeutic Strategies

Brain tumor-initiating cells (BTICs) have been identified as key contributors to therapy resistance, recurrence, and progression of diffuse gliomas, particularly glioblastoma (GBM). BTICs are elusive therapeutic targets that reside across the blood–brain barrier, underscoring the urgent need to develop novel therapeutic strategies. Additionally, intratumoral heterogeneity and adaptations to therapeutic pressure by BTICs impede the discovery of effective anti-BTIC therapies and limit the efficacy of individual gene targeting. Recent discoveries in the genetic and epigenetic determinants of BTIC tumorigenesis offer novel opportunities for RNAi-mediated targeting of BTICs. Here we show that BTIC growth arrest in vitro and in vivo is accomplished via concurrent siRNA knockdown of four transcription factors (SOX2, OLIG2, SALL2, and POU3F2) that drive the proneural BTIC phenotype delivered by multiplexed siRNA encapsulation in the lipopolymeric nanoparticle 7C1. Importantly, we demonstrate that 7C1 nano-encapsulation of multiplexed RNAi is a viable BTIC-targeting strategy when delivered directly in vivo in an established mouse brain tumor. Therapeutic potential was most evident via a convection-enhanced delivery method, which shows significant extension of median survival in two patient-derived BTIC xenograft mouse models of GBM. Our study suggests that there is potential advantage in multiplexed targeting strategies for BTICs and establishes a flexible nonviral gene therapy platform with the capacity to channel multiplexed RNAi schemes to address the challenges posed by tumor heterogeneity.

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Approaches to identifying drug resistance mechanisms to clinically relevant treatments in childhood rhabdomyosarcoma

Cancer Drug Resistance ◽

10.20517/cdr.2021.112 ◽

2022 ◽

Author(s):

Samson Ghilu ◽

Christopher L. Morton ◽

Angelina V. Vaseva ◽

Siyuan Zheng ◽

Raushan T. Kurmasheva ◽

...

Keyword(s):

Drug Resistance ◽

High Risk ◽

Tumor Regression ◽

Population Level ◽

Therapy Resistance ◽

Resistance Mechanisms ◽

Tumor Resistance ◽

Intrinsic Resistance ◽

Clinical Resistance

Aim: Despite aggressive multiagent protocols, patients with metastatic rhabdomyosarcoma (RMS) have poor prognosis. In a recent high-risk trial (ARST0431), 25% of patients failed within the first year, while on therapy and 80% had tumor progression within 24 months. However, the mechanisms for tumor resistance are essentially unknown. Here we explore the use of preclinical models to develop resistance to complex chemotherapy regimens used in ARST0431. Methods: A Single Mouse Testing (SMT) protocol was used to evaluate the sensitivity of 34 RMS xenograft models to one cycle of vincristine, actinomycin D, cyclophosphamide (VAC) treatment. Tumor response was determined by caliper measurement, and tumor regression and event-free survival (EFS) were used as endpoints for evaluation. Treated tumors at regrowth were transplanted into recipient mice, and the treatment was repeated until tumors progressed during the treatment period (i.e., became resistant). At transplant, tumor tissue was stored for biochemical and omics analysis. Results: The sensitivity to VAC of 34 RMS models was determined. EFS varied from 3 weeks to > 20 weeks. Tumor models were classified as having intrinsic resistance, intermediate sensitivity, or high sensitivity to VAC therapy. Resistance to VAC was developed in multiple models after 2-5 cycles of therapy; however, there were examples where sensitivity remained unchanged after 3 cycles of treatment. Conclusion: The SMT approach allows for in vivo assessment of drug sensitivity and development of drug resistance in a large number of RMS models. As such, it provides a platform for assessing in vivo drug resistance mechanisms at a “population” level, simulating conditions in vivo that lead to clinical resistance. These VAC-resistant models represent “high-risk” tumors that mimic a preclinical phase 2 population and will be valuable for identifying novel agents active against VAC-resistant disease.

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Pharmacological Inhibition of USP7 Supresses Growth and Metastasis of Melanoma Cells in Vitro and in Vivo

10.21203/rs.3.rs-117715/v1 ◽

2020 ◽

Author(s):

Minmin Xiang ◽

Long Liang ◽

Xinwei Kuang ◽

Zuozhong Xie ◽

Jing Liu ◽

...

Keyword(s):

Scratch Test ◽

Resistance Mechanisms ◽

Melanoma Cells ◽

Migration And Invasion ◽

Western Blot Assay ◽

Novel Therapeutic Strategies ◽

Novel Therapeutic

Abstract Background: Melanoma is a highly aggressive type of skin cancer. Due to the development of diverse resistance mechanisms and severe adverse side effects, significantly limits the efficiency of current therapeutic approaches. Identification of the new therapeutic targets involved in the pathogenesis will benefit to develop novel therapeutic strategies. The deubiquitinase USP7(ubiquitin-specific protease-7) is deregulated in serval cancer types, as a potential target for cancer treatment, but its role in melanoma is still unclear. Here, we investigated the role of USP7 and its inhibitor P22077 in melanoma treatment.Methods: To explore the role of USP7 and the anti-tuomr effect of P22077 in melanma progression and metastasis, a series of cell biological, molecular and biochemical approaches were used for in vitro and in vivo investigations.These methods included RT-qPCR, Western blot assay, cell transfection, CCK8 assay, flow cytometry, scratch test, Transwell assay, mouse xenograft,TUNEL staining.Results:The USP7 inhibitor P22077 suppressed the growth of melanoma in vitro and in vivo. additionally, P22077 induction of cell cycle arrest and apoptosis via ROS(reactive oxygen species) accumulation-induced DNA damage. Furthermore, inhibition of USP7 also prevented migration and invasion of melanoma cells in vitro and in vivo by decrease the Wnt/β-catenin signal pathway. Conclusion: Our data indicated that USP7 acts as an oncogene involved in melanoma cell proliferation and metastasis and may provide a novel therapeutic target for melanoma treatment.

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Cancer Stem Cells: Powerful Targets to Improve Current Anticancer Therapeutics

Stem Cells International ◽

10.1155/2019/9618065 ◽

2019 ◽

Vol 2019 ◽

pp. 1-15 ◽

Cited By ~ 11

Author(s):

Rayana L. Bighetti-Trevisan ◽

Lucas O. Sousa ◽

Rogerio M. Castilho ◽

Luciana O. Almeida

Keyword(s):

Stem Cells ◽

Cancer Stem Cells ◽

Cancer Cells ◽

Resistance Mechanisms ◽

In Vivo Studies ◽

Tumor Resistance ◽

Therapeutic Implications ◽

Anticancer Therapeutics

A frequent observation in several malignancies is the development of resistance to therapy that results in frequent tumor relapse and metastasis. Much of the tumor resistance phenotype comes from its heterogeneity that halts the ability of therapeutic agents to eliminate all cancer cells effectively. Tumor heterogeneity is, in part, controlled by cancer stem cells (CSC). CSC may be considered the reservoir of cancer cells as they exhibit properties of self-renewal and plasticity and the capability of reestablishing a heterogeneous tumor cell population. The endowed resistance mechanisms of CSC are mainly attributed to several factors including cellular quiescence, accumulation of ABC transporters, disruption of apoptosis, epigenetic reprogramming, and metabolism. There is a current need to develop new therapeutic drugs capable of targeting CSC to overcome tumor resistance. Emerging in vitro and in vivo studies strongly support the potential benefits of combination therapies capable of targeting cancer stem cell-targeting agents. Clinical trials are still underway to address the pharmacokinetics, safety, and efficacy of combination treatment. This review will address the main characteristics, therapeutic implications, and perspectives of targeting CSC to improve current anticancer therapeutics.

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Tumor Resistance against ALK Targeted Therapy-Where It Comes From and Where It Goes

Cancers ◽

10.3390/cancers10030062 ◽

2018 ◽

Vol 10 (3) ◽

pp. 62 ◽

Cited By ~ 27

Author(s):

Geeta Sharma ◽

Ines Mota ◽

Luca Mologni ◽

Enrico Patrucco ◽

Carlo Gambacorti-Passerini ◽

...

Keyword(s):

Kinase Inhibitors ◽

Resistance Mechanisms ◽

Therapeutic Strategies ◽

Tumor Resistance ◽

Alk Inhibitors ◽

Anaplastic Lymphoma ◽

Development Of Resistance ◽

Fda Approval ◽

Novel Therapeutic Strategies

Anaplastic lymphoma kinase (ALK) is a validated molecular target in several ALK-rearranged malignancies, particularly in non-small-cell lung cancer (NSCLC), which has generated considerable interest and effort in developing ALK tyrosine kinase inhibitors (TKI). Crizotinib was the first ALK inhibitor to receive FDA approval for ALK-positive NSCLC patients treatment. However, the clinical benefit observed in targeting ALK in NSCLC is almost universally limited by the emergence of drug resistance with a median of occurrence of approximately 10 months after the initiation of therapy. Thus, to overcome crizotinib resistance, second/third-generation ALK inhibitors have been developed and received, or are close to receiving, FDA approval. However, even when treated with these new inhibitors tumors became resistant, both in vitro and in clinical settings. The elucidation of the diverse mechanisms through which resistance to ALK TKI emerges, has informed the design of novel therapeutic strategies to improve patients disease outcome. This review summarizes the currently available knowledge regarding ALK physiologic function/structure and neoplastic transforming role, as well as an update on ALK inhibitors and resistance mechanisms along with possible therapeutic strategies that may overcome the development of resistance.

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Disruption of the ciliary GTPase Arl13b suppresses Sonic hedgehog overactivation and inhibits medulloblastoma formation

Proceedings of the National Academy of Sciences ◽

10.1073/pnas.1706977115 ◽

2018 ◽

Vol 115 (7) ◽

pp. 1570-1575 ◽

Cited By ~ 20

Author(s):

Sarah N. Bay ◽

Alyssa B. Long ◽

Tamara Caspary

Keyword(s):

Sonic Hedgehog ◽

Pediatric Brain Tumor ◽

Resistance Mechanisms ◽

Tumor Formation ◽

Tumor Resistance ◽

Shh Signaling ◽

Genetic Ablation ◽

Primary Mouse

Medulloblastoma (MB) is the most common malignant pediatric brain tumor, and overactivation of the Sonic Hedgehog (Shh) signaling pathway, which requires the primary cilium, causes 30% of MBs. Current treatments have known negative side effects or resistance mechanisms, so new treatments are necessary. Shh signaling mutations, like those that remove Patched1 (Ptch1) or activate Smoothened (Smo), cause tumors dependent on the presence of cilia. Genetic ablation of cilia prevents these tumors by removing Gli activator, but cilia are a poor therapeutic target since they support many biological processes. A more appropriate strategy would be to identify a protein that functionally disentangles Gli activation and ciliogenesis. Our mechanistic understanding of the ciliary GTPase Arl13b predicts that it could be such a target. Arl13b mutants retain short cilia, and loss of Arl13b results in ligand-independent, constitutive, low-level pathway activation but prevents maximal signaling without disrupting Gli repressor. Here, we show that deletion of Arl13b reduced Shh signaling levels in the presence of oncogenic SmoA1, suggesting Arl13b acts downstream of known tumor resistance mechanisms. Knockdown of ARL13B in human MB cell lines and in primary mouse MB cell culture decreased proliferation. Importantly, loss of Arl13b in a Ptch1-deleted mouse model of MB inhibited tumor formation. Postnatal depletion of Arl13b does not lead to any overt phenotypes in the epidermis, liver, or cerebellum. Thus, our in vivo and in vitro studies demonstrate that disruption of Arl13b inhibits cilia-dependent oncogenic Shh overactivation.

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Detecting apoptosis as a clinical endpoint for proof of a clinical principle

Ophthalmologica ◽

10.1159/000513584 ◽

2020 ◽

Author(s):

Piero Zollet ◽

Timothy E.Yap ◽

M Francesca Cordeiro

Keyword(s):

Drug Development ◽

Therapeutic Response ◽

Imaging Techniques ◽

Brain Diseases ◽

Promising Strategy ◽

Sight Loss ◽

Apoptosis Detection ◽

Novel Therapeutic Strategies

The transparent eye media represent a window through which to observe changes occurring in the retina during pathological processes. In contrast to visualising the extent of neurodegenerative damage that has already occurred, imaging an active process such as apoptosis has the potential to report on disease progression and therefore the threat of irreversible functional loss in various eye and brain diseases. Early diagnosis in these conditions is an important unmet clinical need to avoid or delay irreversible sight loss. In this setting, apoptosis detection is a promising strategy with which to diagnose, provide prognosis, and monitor therapeutic response. Additionally, monitoring apoptosis in vitro and in vivo has been shown to be valuable for drug development in order to assess the efficacy of novel therapeutic strategies both in the pre-clinical and clinical setting. Detection of Apoptosing Retinal Cells (DARC) technology is to date the only tool of its kind to have been tested in clinical trials, with other new imaging techniques under investigation in the fields of neuroscience, ophthalmology and drug development. We summarize the transitioning of techniques detecting apoptosis from bench to bedside, along with the future possibilities they encase.

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LINC-PINT impedes DNA repair and enhances radiotherapeutic response by targeting DNA-PKcs in nasopharyngeal cancer

Cell Death and Disease ◽

10.1038/s41419-021-03728-2 ◽

2021 ◽

Vol 12 (5) ◽

Author(s):

You-hong Wang ◽

Zhen Guo ◽

Liang An ◽

Yong Zhou ◽

Heng Xu ◽

...

Keyword(s):

Dna Damage ◽

Nasopharyngeal Cancer ◽

Noncoding Rnas ◽

Dependent Protein Kinase ◽

Damage Repair ◽

Dependent Protein ◽

Cancer Tissues

AbstractRadioresistance continues to be the leading cause of recurrence and metastasis in nasopharyngeal cancer. Long noncoding RNAs are emerging as regulators of DNA damage and radioresistance. LINC-PINT was originally identified as a tumor suppressor in various cancers. In this study, LINC-PINT was significantly downregulated in nasopharyngeal cancer tissues than in rhinitis tissues, and low LINC-PINT expressions showed poorer prognosis in patients who received radiotherapy. We further identified a functional role of LINC-PINT in inhibiting the malignant phenotypes and sensitizing cancer cells to irradiation in vitro and in vivo. Mechanistically, LINC-PINT was responsive to DNA damage, inhibiting DNA damage repair through ATM/ATR-Chk1/Chk2 signaling pathways. Moreover, LINC-PINT increased radiosensitivity by interacting with DNA-dependent protein kinase catalytic subunit (DNA-PKcs) and negatively regulated the expression and recruitment of DNA-PKcs. Therefore, these findings collectively support the possibility that LINC-PINT serves as an attractive target to overcome radioresistance in NPC.

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Localization matters: nuclear-trapped Survivin sensitizes glioblastoma cells to temozolomide by elevating cellular senescence and impairing homologous recombination

Cellular and Molecular Life Sciences ◽

10.1007/s00018-021-03864-0 ◽

2021 ◽

Author(s):

Thomas R. Reich ◽

Christian Schwarzenbach ◽

Juliana Brandstetter Vilar ◽

Sven Unger ◽

Fabian Mühlhäusler ◽

...

Keyword(s):

Homologous Recombination ◽

Nuclear Export ◽

Cell Model ◽

Chromosome Instability ◽

Direct Interaction ◽

High Grade Glioma ◽

Strand Break ◽

Γh2ax Foci

AbstractTo clarify whether differential compartmentalization of Survivin impacts temozolomide (TMZ)-triggered end points, we established a well-defined glioblastoma cell model in vitro (LN229 and A172) and in vivo, distinguishing between its nuclear and cytoplasmic localization. Expression of nuclear export sequence (NES)-mutated Survivin (SurvNESmut-GFP) led to impaired colony formation upon TMZ. This was not due to enhanced cell death but rather due to increased senescence. Nuclear-trapped Survivin reduced homologous recombination (HR)-mediated double-strand break (DSB) repair, as evaluated by γH2AX foci formation and qPCR-based HR assay leading to pronounced induction of chromosome aberrations. Opposite, clones, expressing free-shuttling cytoplasmic but not nuclear-trapped Survivin, could repair TMZ-induced DSBs and evaded senescence. Mass spectrometry-based interactomics revealed, however, no direct interaction of Survivin with any of the repair factors. The improved TMZ-triggered HR activity in Surv-GFP was associated with enhanced mRNA and stabilized RAD51 protein expression, opposite to diminished RAD51 expression in SurvNESmut cells. Notably, cytoplasmic Survivin could significantly compensate for the viability under RAD51 knockdown. Differential Survivin localization also resulted in distinctive TMZ-triggered transcriptional pathways, associated with senescence and chromosome instability as shown by global transcriptome analysis. Orthotopic LN229 xenografts, expressing SurvNESmut exhibited diminished growth and increased DNA damage upon TMZ, as manifested by PCNA and γH2AX foci expression, respectively, in brain tissue sections. Consequently, those mice lived longer. Although tumors of high-grade glioma patients expressed majorly nuclear Survivin, they exhibited rarely NES mutations which did not correlate with survival. Based on our in vitro and xenograft data, Survivin nuclear trapping would facilitate glioma response to TMZ.

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Genetic Suppressor Element 1 (GSE1) Promotes the Oncogenic and Recurrent Phenotypes of Castration-Resistant Prostate Cancer by Targeting Tumor-Associated Calcium Signal Transducer 2 (TACSTD2)

Cancers ◽

10.3390/cancers13163959 ◽

2021 ◽

Vol 13 (16) ◽

pp. 3959

Author(s):

Oluwaseun Adebayo Bamodu ◽

Yuan-Hung Wang ◽

Chen-Hsun Ho ◽

Su-Wei Hu ◽

Chia-Da Lin ◽

...

Keyword(s):

Prostate Cancer ◽

Disease Progression ◽

Therapy Resistance ◽

Calcium Signal ◽

Signal Transducer ◽

Castration Resistance ◽

Castration Resistant

Background: prostate cancer (PCa) is a principal cause of cancer-related morbidity and mortality. Castration resistance and metastasis are clinical challenges and continue to impede therapeutic success, despite diagnostic and therapeutic advances. There are reports of the oncogenic activity of genetic suppressor element (GSE)1 in breast and gastric cancers; however, its role in therapy resistance, metastasis, and susceptibility to disease recurrence in PCa patients remains unclear. Objective: this study investigated the role of aberrantly expressed GSE1 in the metastasis, therapy resistance, relapse, and poor prognosis of advanced PCa. Methods: we used a large cohort of multi-omics data and in vitro, ex vivo, and in vivo assays to investigate the potential effect of altered GSE1 expression on advanced/castration-resistant PCa (CRPC) treatment responses, disease progression, and prognosis. Results: using a multi-cohort approach, we showed that GSE1 is upregulated in PCa, while tumor-associated calcium signal transducer 2 (TACSTD2) is downregulated. Moreover, the direct, but inverse, correlation interaction between GSE1 and TACSTD2 drives metastatic disease, castration resistance, and disease progression and modulates the clinical and immune statuses of patients with PCa. Patients with GSE1highTACSTD2low expression are more prone to recurrence and disease-specific death than their GSE1lowTACSTD2high counterparts. Interestingly, we found that the GSE1–TACSTD2 expression profile is associated with the therapy responses and clinical outcomes in patients with PCa, especially those with metastatic/recurrent disease. Furthermore, we demonstrate that the shRNA-mediated targeting of GSE1 (shGSE1) significantly inhibits cell proliferation and attenuates cell migration and tumorsphere formation in metastatic PC3 and DU145 cell lines, with an associated suppression of VIM, SNAI2, and BCL2 and the concomitant upregulation of TACSTD2 and BAX. Moreover, shGSE1 enhances sensitivity to the antiandrogens abiraterone and enzalutamide in vitro and in vivo. Conclusion: these data provide preclinical evidence of the oncogenic role of dysregulated GSE1–TACSTD2 signaling and show that the molecular or pharmacological targeting of GSE1 is a workable therapeutic strategy for inhibiting androgen-driven oncogenic signals, re-sensitizing CRPC to treatment, and repressing the metastatic/recurrent phenotypes of patients with PCa.

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