Targeting Integrin α3 Blocks ß1 Maturation, Triggers Endoplasmic Reticulum Stress, and Sensitizes Glioblastoma Cells to TRAIL-Mediated Apoptosis.

Glioblastoma (GBM) is a devastating brain cancer for which new effective therapies are urgently needed. GBM, after an initial response to current treatment regimens, develops therapeutic resistance, leading to rapid patient demise. Cancer cells exhibit an inherent elevation of endoplasmic reticulum (ER) stress due to uncontrolled growth and an unfavorable microenvironment, including hypoxia and nutrient deprivation. Cancer cells utilize the unfolded protein response (UPR) to maintain ER homeostasis, and failure of this response promotes cell death. In this study, as integrins are upregulated in cancer, we have evaluated the therapeutic potential of individually targeting all αß1 integrin subunits using RNA interference. We found that GBM cells are uniquely susceptible to silencing of integrin α3. Knockdown of α3-induced proapoptotic markers such as PARP cleavage and caspase 3 and 8 activation. Remarkably, we discovered a non-canonical function for α3 in mediating the maturation of integrin ß1. In its absence, generation of full length ß1 was reduced, immature ß1 accumulated, and the cells underwent elevated ER stress with upregulation of death receptor 5 (DR5) expression. Targeting α3 sensitized TRAIL-resistant GBM cancer cells to TRAIL-mediated apoptosis and led to growth inhibition. Our findings offer key new insights into integrin α3's role in GBM survival via the regulation of ER homeostasis and its value as a therapeutic target.

Diethyldithiocarbamate-ferrous oxide nanoparticles inhibit human and mouse glioblastoma stemness: aldehyde dehydrogenase 1A1 suppression and ferroptosis induction.

The development of effective therapy for eradicating glioblastoma stem cells remains a major challenge due to their aggressive growth, chemoresistance and radioresistance which are mainly conferred by aldehyde dehydrogenase (ALDH)1A1. The latter is the main stemness mediator via enhancing signaling pathways of Wnt/ß-catenin, phosphatidylinositol 3-kinase/AKT, and hypoxia. Furthermore, ALDH1A1 mediates therapeutic resistance by inactivating drugs, stimulating the expression of drug efflux transporters, and detoxifying reactive radical species, thereby apoptosis arresting. Recent reports disclosed the potent and broad-spectrum anticancer activities of the unique nanocomplexes of diethyldithiocarbamate (DE, ALDH1A1 inhibitor) with ferrous oxide nanoparticles (FeO NPs) mainly conferred by inducing lipid peroxidation-dependent non-apoptotic pathways (iron accumulation-triggered ferroptosis), was reported. Accordingly, the anti-stemness activity of nanocomplexes (DE-FeO NPs) was investigated against human and mouse glioma stem cells (GSCs) and radioresistant GSCs (GSCs-RR). DE-FeO NPs exhibited the strongest growth inhibition effect on the treated human GSCs (MGG18 and JX39P), mouse GSCs (GS and PDGF-GSC) and their radioresistant cells (IC50 ≤ 70 and 161 µg/mL, respectively). DE-FeO NPs also revealed a higher inhibitory impact than standard chemotherapy (temozolomide, TMZ) on self-renewal, cancer repopulation, chemoresistance, and radioresistance potentials. Besides, DE-FeO NPs surpassed TMZ regarding the effect on relative expression of all studied stemness genes, as well as relative p-AKT/AKT ratio in the treated MGG18, GS and their radioresistant (MGG18-RR and GS-RR). This potent anti-stemness influence is primarily attributed to ALDH1A1 inhibition and ferroptosis induction, as confirmed by significant elevation of cellular reactive oxygen species and lipid peroxidation with significant depletion of glutathione and glutathione peroxidase 4. DE-FeO NPs recorded the optimal LogP value for crossing the blood brain barrier. This in vitro novel study declared the potency of DE-FeO NPs for collapsing GSCs and GSCs-RR with improving their sensitivity to chemotherapy and radiotherapy, indicating that DE-FeO NPs may be a promising remedy for GBM. Glioma animal models will be needed for in-depth studies on its safe effectiveness.

Site-oriented conjugation of poly(2-methacryloyloxyethyl phosphorylcholine) for enhanced brain delivery of antibody.

Antibody therapeutics are limited in treating brain diseases due to poor blood-brain barrier (BBB) penetration. We have discovered that poly 2-methacryloyloxyethyl phosphorylcholine (PMPC), a biocompatible polymer, effectively facilitates BBB penetration via receptor-mediated transcytosis and have developed a PMPC-shell-based platform for brain delivery of therapeutic antibodies, termed nanocapsule. Yet, the platform results in functional loss of antibodies due to epitope masking by the PMPC polymer network, which necessitates the incorporation of a targeting moiety and degradable crosslinker to enable on-site antibody release. In this study, we developed a novel platform based on site-oriented conjugation of PMPC to the antibody, allowing it to maintain key functionalities of the original antibody. With an optimized PMPC chain length, the PMPC-antibody conjugate exhibited enhanced brain delivery while retaining epitope recognition, cellular internalization, and antibody-dependent cellular phagocytic activity. This simple formula incorporates only the antibody and PMPC without requiring additional components, thereby addressing the issues of the nanocapsule platform and paving the way for PMPC-based brain delivery strategies for antibodies.

Epigenetic upregulation of Schlafen11 renders WNT- and SHH-activated medulloblastomas sensitive to cisplatin.

BACKGROUND: Intensive chemotherapeutic regimens with craniospinal irradiation have greatly improved survival in medulloblastoma patients. However, survival markedly differs among molecular subgroups and their biomarkers are unknown. Through unbiased screening, we found Schlafen family member 11 (SLFN11), which is known to improve response to DNA damaging agents in various cancers, to be one of the top prognostic markers in medulloblastomas. Hence, we explored the expression and functions of SLFN11 in medulloblastoma. METHODS: SLFN11 expression for each subgroup was assessed by immunohistochemistry in 98 medulloblastoma patient samples and by analyzing transcriptomic databases. We genetically or epigenetically modulated SLFN11 expression in medulloblastoma cell lines and determined cytotoxic response to the DNA damaging agents cisplatin and topoisomerase I inhibitor SN-38 in vitro and in vivo. RESULTS: High SLFN11 expressing cases exhibited significantly longer survival than low expressing cases. SLFN11 was highly expressed in the WNT-activated subgroup and in a proportion of the SHH-activated subgroup. While WNT activation was not a direct cause of the high expression of SLFN11, a specific hypomethylation locus on the SLFN11 promoter was significantly correlated with high SLFN11 expression. Overexpression or deletion of SLFN11 made medulloblastoma cells sensitive and resistant to cisplatin and SN-38, respectively. Pharmacological upregulation of SLFN11 by the brain-penetrant histone deacetylase-inhibitor RG2833 markedly increased sensitivity to cisplatin and SN-38 in SLFN11-negative medulloblastoma cells. Intracranial xenograft studies also showed marked sensitivity to cisplatin by SLFN11-overexpression in medulloblastoma cells. CONCLUSIONS: High SLFN11 expression is one factor which renders favorable outcomes in WNT-activated and a subset of SHH-activated medulloblastoma possibly through enhancing response to cisplatin.

Skewed fate and hematopoiesis of CD34+ HSPCs in umbilical cord blood amid the COVID-19 pandemic.

Umbilical cord blood (UCB) is an irreplaceable source for hematopoietic stem progenitor cells (HSPCs). However, the effects of SARS-CoV-2 infection and COVID-19 vaccination on UCB phenotype, specifically the HSPCs therein, are currently unknown. We thus evaluated any effects of SARS-CoV-2 infection and/or COVID-19 vaccination from the mother on the fate and functionalities of HSPCs in the UCB. The numbers and frequencies of HSPCs in the UCB decreased significantly in donors with previous SARS-CoV-2 infection and more so with COVID-19 vaccination via the induction of apoptosis, likely mediated by IFN-γ-dependent pathways. Two independent hematopoiesis assays, a colony forming unit assay and a mouse humanization assay, revealed skewed hematopoiesis of HSPCs obtained from donors delivered from mothers with SARS-CoV-2 infection history. These results indicate that SARS-CoV-2 infection and COVID-19 vaccination impair the functionalities and survivability of HSPCs in the UCB, which would make unprecedented concerns on the future of HSPC-based therapies.

Viral Particle-Mediated SAMHD1 Depletion Sensitizes Refractory Glioblastoma to DNA-Damaging Therapeutics by Impairing Homologous Recombination.

The current standard-of-care treatment for glioblastoma includes DNA damaging agents, γ-irradiation (IR) and temozolomide (TMZ). These treatments fail frequently and there is limited alternative strategy. Therefore, identifying a new therapeutic target is urgently needed to develop a strategy that improves the efficacy of the existing treatments. Here, we report that tumor samples from GBM patients express a high level of SAMHD1, emphasizing SAMHD1's importance. The depletion of SAMHD1 using virus-like particles containing Vpx, VLP(+Vpx), sensitized two independent GBM cell lines (LN-229 and U-87) to veliparib, a well-established PARP inhibitor, and slowed cell growth in a dose-dependent manner. In the mouse GBM xenograft model, Vpx-mediated SAMHD1 depletion reduced tumor growth and SAMHD1 knockout (KO) improved survival. In combination with IR or TMZ, SAMHD1 KO and exposure to 50% growth inhibitory dose (gID50) of VLP(+Vpx) displayed a synergistic effect, resulting in impaired HR, and improved LN-229 cells' sensitivity to TMZ and IR. In conclusion, our finding demonstrates that SAMHD1 promotes GBM resistance to treatment, and it is a plausible therapeutic target to improve the efficacy of TMZ and IR in GBM. Furthermore, we show that Vpx could be a potential therapeutic tool that can be utilized to deplete SAMHD1 in GBM.

Targeting HIF-activated collagen prolyl 4-hydroxylase expression disrupts collagen deposition and blocks primary and metastatic uveal melanoma growth.

Uveal melanoma (UM) is the most prevalent primary intraocular malignancy in adults, and patients that develop metastases (~50%) survive <1 year, highlighting the urgent need for new therapies. TCGA has recently revealed that a hypoxia gene signature is associated with poor UM patient prognosis. Here we show that expression of hypoxia-regulated collagen prolyl-4-hydroxylase genes P4HA1 and P4HA2 is significantly upregulated in UM patients with metastatic disease and correlates with poor prognosis, suggesting these enzymes might be key tumor drivers. We targeted hypoxia-induced expression of P4HA1/2 in UM with KCN1, a hypoxia inducible factor-1 (HIF-1) pathway inhibitor and found potent inhibition of primary and metastatic disease and extension of animal survival, without overt side effects. At the molecular level, KCN1 antagonized hypoxia-induced expression of P4HA1 and P4HA2, which regulate collagen maturation and deposition in the extracellular matrix. The treatment decreased prolyl hydroxylation, induced proteolytic cleavage and rendered a disordered structure to collagen VI, the main collagen produced by UM, and reduced UM cell invasion. Together, these data demonstrate that extracellular collagen matrix formation can be targeted in UM by inhibiting hypoxia-induced P4HA1 and P4HA2 expression, warranting further development of this strategy in patients with uveal melanoma.

[Global Trends in Pre-clinical Research on Malignant Glioma].

Finding novel treatment approaches for brain tumors is challenging, especially for malignant gliomas. A wealth of genetic and expression data on malignant glioma has accumulated in recent years; however, therapies targeting the underlying oncogenic pathways have not succeeded in substantially improving therapeutic responses or survival, owning to tumor resistance mechanisms to these therapies. Therefore, new therapeutic approaches are necessary to reduce the mortality rates in patients with glioma. This study examined current trends in preclinical research for malignant glioma to predict future therapies. This analysis revealed that current preclinical research mainly focused on the immune response and tumor microenvironment. Knowledge from these researches may lead to the development of new therapeutics for the management of malignant glioma.

N-cadherin upregulation mediates adaptive radioresistance in glioblastoma.

Glioblastoma (GBM) is composed of heterogeneous tumor cell populations, including those with stem cell properties, termed glioma stem cells (GSCs). GSCs are innately less radiation sensitive than the tumor bulk and are believed to drive GBM formation and recurrence after repeated irradiation. However, it is unclear how GSCs adapt to escape the toxicity of repeated irradiation used in clinical practice. To identify important mediators of adaptive radioresistance in GBM, we generated radioresistant human and mouse GSCs by exposing them to repeat cycles of irradiation. Surviving subpopulations acquired strong radioresistance in vivo, which was accompanied by a reduction in cell proliferation and an increase in cell-cell adhesion and N-cadherin expression. Increasing N-cadherin expression rendered parental GSCs radioresistant, reduced their proliferation, and increased their stemness and intercellular adhesive properties. Conversely, radioresistant GSCs lost their acquired phenotypes upon CRISPR/Cas9-mediated knockout of N-cadherin. Mechanistically, elevated N-cadherin expression resulted in the accumulation of ß-catenin at the cell surface, which suppressed Wnt/ß-catenin proliferative signaling, reduced neural differentiation, and protected against apoptosis through Clusterin secretion. N-cadherin upregulation was induced by radiation-induced IGF1 secretion, and the radiation resistance phenotype could be reverted with picropodophyllin, a clinically applicable blood-brain-barrier permeable IGF1 receptor inhibitor, supporting clinical translation.

Progression-free survival of prostate cancer patients is prolonged with a higher regucalcin expression in the tumor tissues: Overexpressed regucalcin suppresses the growth and bone activity in human prostate cancer cells.

Prostate cancer, which is a bone metastatic cancer, is the second leading cause of cancer-related death in men. There is no effective treatment for metastatic prostate cancer. Regucalcin has been shown to contribute as a suppressor in various types of human cancers. In the present study, furthermore, we investigate an involvement of regucalcin in suppression of prostate cancer. Regucalcin expression was compared in 131 primary tumor tissues and 19 metastatic tumor tissues in prostate cancer patients. Regucalcin expression in the metastatic tumor was found to be reduced as compared with that in primary tumor. The progression-free survival rate was prolonged in patients with a higher regucalcin expression. Translationally, overexpression of regucalcin in bone metastatic human prostate cancer PC-3 and DU-145 cells suppressed colony formation and cell growth in vitro. Mechanistically, overexpressed regucalcin enhanced the levels of p53, Rb, and p21, and decreased the levels of Ras, PI3 kinase, Akt, and mitogen-activated protein kinase, leading to suppression of cell growth. Furthermore, higher regucalcin expression suppressed the levels of nuclear factor-κB p65, ß-catenin, and signal transducer and activator of transcription 3, which regulate a transcription activity. Cell growth was promoted by culturing with the calcium agonist Bay K 8644. This effect was blocked by overexpression of regucalcin. Notably, overexpressed regucalcin suppressed bone metastatic activity of PC-3 and DU-145 cells when cocultured with preosteoblastic or preosteoclastic cells. Regucalcin may suppress the development of human prostate cancer, suggesting that gene delivery systems in which its expression is forced may be a novel therapeutic strategy.

The Inhibitor of Apoptosis Protein Livin Confers Resistance to Fas-Mediated Immune Cytotoxicity in Refractory Lymphoma.

Death receptor Fas-mediated apoptosis not only eliminates nonspecific and autoreactive B cells but also plays a major role in antitumor immunity. However, the possible mechanisms underlying impairment of Fas-mediated induction of apoptosis during lymphomagenesis remain unknown. In this study, we employed our developed syngeneic lymphoma model to demonstrate that downregulation of Fas is required for both lymphoma development and lymphoma cell survival to evade immune cytotoxicity. CD40 signal activation significantly restored Fas expression and thereby induced apoptosis after Fas ligand treatment in both mouse and human lymphoma cells. Nevertheless, certain human lymphoma cell lines were found to be resistant to Fas-mediated apoptosis, with Livin (melanoma inhibitor of apoptosis protein; ML-IAP) identified as a driver of such resistance. High expression of Livin and low expression of Fas were associated with poor prognosis in patients with aggressive non-Hodgkin's lymphoma. Livin expression was tightly driven by bromodomain and extraterminal (BET) proteins BRD4 and BRD2, suggesting that Livin expression is epigenetically regulated in refractory lymphoma cells to protect them from Fas-mediated apoptosis. Accordingly, the combination of CD40-mediated Fas restoration with targeting of the BET proteins-Livin axis may serve as a promising immunotherapeutic strategy for refractory B-cell lymphoma. SIGNIFICANCE: These findings yield insights into identifying risk factors in refractory lymphoma and provide a promising therapy for tumors resistant to Fas-mediated antitumor immunity. GRAPHICAL ABSTRACT: http://cancerres.aacrjournals.org/content/canres/80/20/4439/F1.large.jpg.

A Chimeric Signal Peptide-Galectin-3 Conjugate Induces Glycosylation-Dependent Cancer Cell-Specific Apoptosis.

PURPOSE: Exploitation of altered glycosylation in cancer is a major goal for the design of new cancer therapy. Here, we designed a novel secreted chimeric signal peptide-Galectin-3 conjugate (sGal-3) and investigated its ability to induce cancer-specific cell death by targeting aberrantly N-glycosylated cell surface receptors on cancer cells. EXPERIMENTAL DESIGN: sGal-3 was genetically engineered from Gal-3 by extending its N-terminus with a noncleavable signal peptide from tissue plasminogen activator. sGal-3 killing ability was tested on normal and tumor cells in vitro and its antitumor activity was evaluated in subcutaneous lung cancer and orthotopic malignant glioma models. The mechanism of killing was investigated through assays detecting sGal-3 interaction with specific glycans on the surface of tumor cells and the elicited downstream proapoptotic signaling. RESULTS: We found sGal-3 preferentially binds to ß1 integrin on the surface of tumor cells due to aberrant N-glycosylation resulting from cancer-associated upregulation of several glycosyltransferases. This interaction induces potent cancer-specific death by triggering an oncoglycan-ß1/calpain/caspase-9 proapoptotic signaling cascade. sGal-3 could reduce the growth of subcutaneous lung cancers and malignant gliomas in brain, leading to increased animal survival. CONCLUSIONS: We demonstrate that sGal-3 kills aberrantly glycosylated tumor cells and antagonizes tumor growth through a novel integrin ß1-dependent cell-extrinsic apoptotic pathway. These findings provide proof-of-principle that aberrant N-oncoglycans represent valid cancer targets and support further translation of the chimeric sGal-3 peptide conjugate for cancer therapy.

Early-Life Microbiota Exposure Restricts Myeloid-Derived Suppressor Cell-Driven Colonic Tumorigenesis.

Gut microbiota and their metabolites are instrumental in regulating homeostasis at intestinal and extraintestinal sites. However, the complex effects of prenatal and early postnatal microbial exposure on adult health and disease outcomes remain incompletely understood. Here, we showed that mice raised under germ-free conditions until weaning and then transferred to specific pathogen-free (SPF) conditions harbored altered microbiota composition, augmented inflammatory cytokine and chemokine expression, and were hyper-susceptible to colitis-associated tumorigenesis later in adulthood. Increased number and size of colon tumors and intestinal epithelial cell proliferation in recolonized germ-free mice were associated with augmented intratumoral CXCL1, CXCL2, and CXCL5 expression and granulocytic myeloid-derived suppressor cell (G-MDSC) accumulation. Consistent with these findings, CXCR2 neutralization in recolonized germ-free mice completely reversed the exacerbated susceptibility to colitis-associated tumorigenesis. Collectively, our findings highlight a crucial role for early-life microbial exposure in establishing intestinal homeostasis that restrains colon cancer in adulthood.

Prolonged survival of renal cancer patients is concomitant with a higher regucalcin gene expression in tumor tissues: Overexpression of regucalcin suppresses the growth of human renal cell carcinoma cells in vitro.

Renal cell carcinoma (RCC), which is a type of cancer found in the kidney tubule, is among the 10 most frequently occurring human cancers. Regucalcin plays a potential role as a regulator of transcriptional activity, and its downregulated expression or activity may contribute to the promotion of human cancers. In this study, we investigated the involvement of regucalcin in human RCC. Regucalcin expression was compared in 23 normal and 29 tumor samples of kidney cortex tissues of patients with clear cell RCC obtained through the Gene Expression Omnibus (GEO) database (GSE36895). Regucalcin expression was downregulated in the tumor tissues. The prolonged survival of patients with clear cell RCC was demonstrated to be associated with a higher regucalcin gene expression in the TCGA dataset. The overexpression of regucalcin suppressed the colony formation, proliferation and the death of human clear cell RCC A498 cells in vitro. Mechanistically, the overexpression of regucalcin induced the G1 and G2/M phase cell cycle arrest of A498 cells through the suppression of multiple signaling components, including Ras, PI3 kinase, Akt and mitogen­activated protein (MAP) kinase. Importantly, the overexpression of regucalcin led to an elevation in the levels of the tumor suppressors, p53, Rb and the cell cycle inhibitor, p21. The levels of the transcription factors, c­fos, c­jun, nuclear factor­κB p65, ß­catenin and signal transducer and activator of transcription 3, were suppressed by regucalcin overexpression. On the whole, the findings of this study suggest that regucalcin plays a suppressive role in the promotion of human RCC. The overexpression of regucalcin by gene delivery systems may thus prove to be a novel therapeutic strategy for RCC.

Arylsulfonamide 64B Inhibits Hypoxia/HIF-Induced Expression of c-Met and CXCR4 and Reduces Primary Tumor Growth and Metastasis of Uveal Melanoma.

PURPOSE: Uveal melanoma (UM) is the most prevalent and lethal intraocular malignancy in adults. Here, we examined the importance of hypoxia in UM growth and tested the antitumor effects of arylsulfonamide 64B, an inhibitor of the hypoxia-induced factor (HIF) pathway in animal models of UM and investigated the related mechanisms. EXPERIMENTAL DESIGN: UM cells were implanted in the uvea of mice eyes and mice systemically treated with 64B. Drug effect on primary eye tumor growth, circulating tumor cells, metastasis formation in liver, and survival were examined. 64B effects on UM cell growth, invasion and hypoxia-induced expression of C-X-C chemokine receptor type 4 (CXCR4) and mesenchymal-epithelial transition factor (c-Met) were measured. Luciferase reporter assays, chromatin immunoprecipitation, co-immunoprecipitation, and cellular thermal shift assays were used to determine how 64B interferes with the HIF transcriptional complex. RESULTS: Systemic administration of 64B had potent antitumor effects against UM in several orthotopic mouse models, suppressing UM growth in the eye (∼70% reduction) and spontaneous liver metastasis (∼50% reduction), and extending mice survival (P < 0.001) while being well tolerated. 64B inhibited hypoxia-induced expression of CXCR4 and c-Met, 2 key drivers of tumor invasion and metastasis. 64B disrupted the HIF-1 complex by interfering with HIF-1α binding to p300/CBP co-factors, thus reducing p300 recruitment to the MET and CXCR4 gene promoters. 64B could thermostabilize p300, supporting direct 64B binding to p300. CONCLUSIONS: Our preclinical efficacy studies support the further optimization of the 64B chemical scaffold toward a clinical candidate for the treatment of UM.

Prolonged survival of patients with colorectal cancer is associated with a higher regucalcin gene expression: Overexpression of regucalcin suppresses the growth of human colorectal carcinoma cells in vitro.

Regucalcin plays a crucial role as a regulator of transcriptional signaling activity, and its decreased expression or activity may contribute to the promotion of human carcinogenesis. A higher regucalcin expression in the tumor tissues has been demonstrated to prolong the survival of patients with various types of cancer, including pancreatic cancer, breast cancer, liver cancer and lung adenocarcinoma. The involvement of regucalcin in human colorectal cancer was investigated in the current study. Regucalcin gene expression and the survival data of 62 patients with colorectal cancer were obtained though the Gene Expression Omnibus (GEO) database (GSE12945) for outcome analysis. The data of gene expression revealed that the prolonged survival of patients with colorectal cancer was associated with a higher regucalcin gene expression in tumor tissues. The overexpression of regucalcin suppressed colony formation and proliferation, and induced the death of human colorectal carcinoma RKO cells cultured in a medium containing fetal bovine serum in vitro. Mechanistically, the overexpression of regucalcin induced the G1 and G2/M phase cell cycle arrest of the RKO cells through the suppression of multiple signaling pathways, including Ras, Akt, mitogen-activated protein (MAP) kinase and SAPK/JNK. Of note, the overexpression of regucalcin induced an increase in the levels of the tumor suppressors, p53 and Rb, and the cell cycle inhibitor, p21. Moreover, the levels of the transcription factors, c­fos, c­jun, nuclear factor (NF)­κB p65, ß-catenin and signal transducer and activator of transcription 3 (Stat3), were suppressed by the overexpression of regucalcin. On the whole, the findings of this study suggest that regucalcin plays a crucial role as a suppressor in human colorectal cancer, and that the suppressed expression of the regucalcin gene may predispose patients to the promotion of colorectal cancer. The overexpression of regucalcin by gene delivery may thus prove to be a novel therapeutic strategy for colorectal cancer.

BAI1 Suppresses Medulloblastoma Formation by Protecting p53 from Mdm2-Mediated Degradation.

Adhesion G protein-coupled receptors (ADGRs) encompass 33 human transmembrane proteins with long N termini involved in cell-cell and cell-matrix interactions. We show the ADGRB1 gene, which encodes Brain-specific angiogenesis inhibitor 1 (BAI1), is epigenetically silenced in medulloblastomas (MBs) through a methyl-CpG binding protein MBD2-dependent mechanism. Knockout of Adgrb1 in mice augments proliferation of cerebellar granule neuron precursors, and leads to accelerated tumor growth in the Ptch1+/- transgenic MB mouse model. BAI1 prevents Mdm2-mediated p53 polyubiquitination, and its loss substantially reduces p53 levels. Reactivation of BAI1/p53 signaling axis by a brain-permeable MBD2 pathway inhibitor suppresses MB growth in vivo. Altogether, our data define BAI1's physiological role in tumorigenesis and directly couple an ADGR to cancer formation.

Assessment of PD-1 positive cells on initial and secondary resected tumor specimens of newly diagnosed glioblastoma and its implications on patient outcome.

Glioblastoma (GBM) is the most common type of malignant brain tumor and has a very poor prognosis. Most patients relapse within 12 months despite aggressive treatment and patient outcome after recurrent is extremely worse. This study was designed to clarify the change of the molecular expression, including programmed cell death 1 (PD-1) and PD-ligand 1 (PD-L1), on the initial and secondary resected tumor specimens and to address the influence of these expressions for patient outcome after second surgery of glioblastoma. We investigated 16 patients, ranging in age from 14 to 65 years, with histologically verified WHO grade IV GBM, whose original tumor was resected between 2008 and 2014, and treated with fractionated radiotherapy and temozolomide. Four patients who were treated with immunotherapy using autologous formalin-fixed tumor vaccine were enrolled. All of the patients underwent secondary resection after tumor recurrence within 24 months. We carried out an immunohistochemical examination of the initial and secondary resected tumors from patients using a panel of immune system molecular markers, and assessed whether marker expression correlated with clinical outcomes. CD3, CD8 and PD-1 on tumor-infiltrating lymphocytes was significantly increased in secondary resected specimens compared with initially resected specimens (p ≤ 0.05). All patients expressed PD-L1 on tumor cells in initial and secondary resection specimens. Patients were divided into high or low expression group by median IHC score of PD-1 on initial or secondary resected specimens. No significant differences in patient outcomes were observed between high and low PD-1 or PD-L1 groups of initially resected specimens. In high expression group of secondary resected specimens, most patients score had increased which compared with initial resected tumor specimens. The PD-1 high expression score group of secondary resected specimens was associated with long progression-free survival and short survival after recurrence. PD-L1 expression was detected in almost all initial and secondary specimens. Patients with high PD-1 expression of secondary specimen had bad prognosis after secondary resection. PD-1/PD-L1 pathway may be associated with patient outcome after second surgery of glioblastoma.