Blood-Brain Barrier Disruption in Preclinical Mouse Models of Stroke Can Be an Experimental Artifact Caused by Craniectomy.

The pathophysiological features of ischemia-related blood-brain barrier (BBB) disruption are widely studied using preclinical stroke models. However, in many of these models, craniectomy is required to confirm arterial occlusion via laser Doppler flowmetry or to enable direct ligation of the cerebral artery. In the present study, mice were used to construct a distal middle cerebral artery occlusion (dMCAO) model, a preclinical stroke model that requires craniectomy to enable direct ligation of the cerebral artery, or were subjected to craniectomy alone. dMCAO but not craniectomy caused neurodegeneration and cerebral infarction, but both procedures induced an appreciable increase in BBB permeability to Evans blue dye, fluorescein, and endogenous albumin but not to 10 kDa dextran-FITC, leading to cerebral edema. Using rats, we further showed that BBB disruption induced by craniectomy with no evidence of dural tearing was comparable to that induced by craniectomy involving tearing of the dura. In conclusion, our data demonstrated that craniectomy can be a major contributor to BBB disruption and cerebral edema in preclinical stroke models. The implications of this experimental artifact for translational stroke research and preclinical data interpretation are discussed.

Regulation of neuroendocrine plasticity by the RNA-binding protein ZFP36L1.

Some small cell lung cancers (SCLCs) are highly sensitive to inhibitors of the histone demethylase LSD1. LSD1 inhibitors are thought to induce their anti-proliferative effects by blocking neuroendocrine differentiation, but the mechanisms by which LSD1 controls the SCLC neuroendocrine phenotype are not well understood. To identify genes required for LSD1 inhibitor sensitivity in SCLC, we performed a positive selection genome-wide CRISPR/Cas9 loss of function screen and found that ZFP36L1, an mRNA-binding protein that destabilizes mRNAs, is required for LSD1 inhibitor sensitivity. LSD1 binds and represses ZFP36L1 and upon LSD1 inhibition, ZFP36L1 expression is restored, which is sufficient to block the SCLC neuroendocrine differentiation phenotype and induce a non-neuroendocrine "inflammatory" phenotype. Mechanistically, ZFP36L1 binds and destabilizes SOX2 and INSM1 mRNAs, two transcription factors that are required for SCLC neuroendocrine differentiation. This work identifies ZFP36L1 as an LSD1 target gene that controls the SCLC neuroendocrine phenotype and demonstrates that modulating mRNA stability of lineage transcription factors controls neuroendocrine to non-neuroendocrine plasticity.

High 18F-fluoro-2-deoxy-D-glucose uptake in adult-type rhabdomyoma of the larynx.

Rhabdomyomas are rare benign mesenchymal tumors of the skeletal muscles and uncommon in the head and neck region. Laryngeal rhabdomyomas are much rarer. We present the case of a 32-year-old woman who was admitted to our hospital for shortness of breath due to pneumothorax. As otolaryngologists, we were consulted for a soft tissue tumor over the left side of the larynx that was accidentally found on the chest computed tomography (CT). The patient underwent laryngomicrosurgery for tumor biopsy, and histological examination revealed a laryngeal rhabdomyoma. After the operation, magnetic resonance imaging of the neck was performed and the tumor was suspected as rhabdomyosarcoma. Positron emission tomography/computed tomography (PET/CT) showed an 18F-fluoro-2-deoxy-D-glucose (FDG)-avid soft tissue mass on the left side of the larynx. After complete tumor removal via transoral laser microsurgery, no recurrence was reported for 5 years.

The new SRS/FSRT technique HyperArc for benign brain lesions: a dosimetric analysis.

To evaluate the potential benefit of HyperArc (HA) fractionated stereotactic radiotherapy (FSRT) for the benign brain lesion. Sixteen patients with a single deep-seated, centrally located benign brain lesion treated by CyberKnife (CK, G4 cone-based model) were enrolled. Treatment plans for HA with two different optimization algorithms (SRS NTO and ALDO) and coplanar RapidArc (RA) were generated for each patient to meet the corresponding treatment plan criteria. These four FSRT treatment plans were divided into two groups-the homogeneous delivery group (HA-SRS NTO and coplanar RA) and the inhomogeneous delivery group (HA-ALDO and cone-based CK)-to compare for dosimetric outcomes. For homogeneous delivery, the brain V5, V12, and V24 and the mean brainstem dose were significantly lower with the HA-SRS NTO plans than with the coplanar RA plans. The conformity index, high and intermediate dose spillage, and gradient radius were significantly better with the HA-SRS NTO plans than with the coplanar RA plans. For inhomogeneous delivery, the HA-ALDO exhibited superior PTV coverage levels to the cone-based CK plans. Almost all the doses delivered to organs at risk and dose distribution metrics were significantly better with the HA-ALDO plans than with the cone-based CK plans. Good dosimetric distribution makes HA an attractive FSRT technique for the treatment of benign brain lesions.

Stroke injury induced by distal middle cerebral artery occlusion is resistant to N-methyl-d-aspartate receptor antagonism in FVB/NJ mice.

Although N-methyl-d-aspartate receptor (NMDAR) antagonism has been shown to have a neuroprotective effect in many preclinical stroke models, the efficacy of this antiexcitotoxicity strategy in clinical trials in stroke patients has been disappointing. Interestingly, it has been reported that NMDAR antagonism is not neuroprotective in C57BL/6 mice subjected to distal middle cerebral artery occlusion (dMCAO), supporting the notion that whether these treatments are neuroprotective depends on the type of cerebral ischemia. However, because C57BL/6 mice are inherently resistant to excitotoxicity, the reported lack of neuroprotection could also be explained by the difference in the mouse strain studied rather than the stroke model used. Here we examined the neuroprotective efficacy of NMDAR antagonism in FVB/NJ mice, an excitotoxicity-prone mouse strain, subjected to dMCAO. Although C57BL/6 mice are known to have an excitotoxicity-resistant genetic background and FVB/NJ mice are known to have an excitotoxicity-prone genetic background, the infarct volume and density of neurodegenerating neurons were similar in the two mouse strains following dMCAO. In addition, none of the antiexcitotoxicity agents studied, including the canonical NMDAR antagonist MK801 and the therapeutic peptides Tat-NR2B9c and L-JNKI-1, protected the FVB/NJ mouse brain against ischemic damage induced by dMCAO. In conclusion, our data demonstrated that FVB/NJ mice are no more susceptible to cerebral ischemia than C57BL/6 mice and that NMDAR antagonism is ineffective in mice, even in an excitotoxicity-prone strain, subjected to dMCAO.

The feasibility and efficacy of new SBRT technique HyperArc for recurrent nasopharyngeal carcinoma: noncoplanar cone-based robotic system vs. noncoplanar high-definition MLC based Linac system.

The purpose of this study was to evaluate the feasibility and efficacy of HyperArc (HA) for recurrent nasopharyngeal cancer (NPC) by comparing it with the CyberKnife system (CK). Fifteen patients with recurrent nasopharyngeal cancer who were treated using the noncoplanar cone-based robotic CK system were enrolled. CK was delivered with a median dose of 37.5 Gy in 5 fractions. The delivered CK treatment plans were the sources for the corresponding homogeneous HA (HA-H) and inhomogeneous HA (HA-IH) plans. The HA-H plans were generated to meet the corresponding treatment plan criteria for the CK plans. The HA-IH plans were designed to emulate the corresponding inhomogeneous CK isodose distributions. These three SBRT treatment plans were compared with target coverage, sparing of organs at risk (OARs), and dose distribution metrics. The HA-H and HA-IH plans consistently exhibited CTV and PTV coverage levels similar or better to those of the CK plans but significantly reduced the dose to OARs. Using the HA techniques (both HA-H and HA-IH plans), the mean maximal doses to the spinal cord, brainstem, optic nerves, and optic chiasm were reduced by approximately 60%, compared to the CK plans. The high dose spillage, conformity, and homogeneity indices of the HA-H plans were significantly better than those of the CK plans. The HA-IH plans showed faster dose falloff and similar conformity of the HA-H plans and dose heterogeneity of the CK plans. Here we demonstrated the HA treatment plan system for recurrent NPC is feasible, either homogeneous or inhomogeneous delivery. Excellent sparing of OARs and dosimetric distribution and very efficient delivery make HA an attractive SBRT technique for recurrent NPC treatment.

Clinical outcomes of fractionated stereotactic radiosurgery in treating perioptic meningiomas and schwannomas: A single-institutional experience.

Application of radiosurgery to the newly diagnosed or post-operative residual perioptic lesions has been proved to improve tumor control. However, risk of vision injury induced by radiosurgery may increase substantially if the radiation dose is too high or tumor is close to the optic apparatus. The purpose of this study was to evaluate the safety and the effectiveness of fractionated stereotactic radiosurgery (FSRS) for perioptic tumors. We retrospectively analyzed 60 consecutive patients with 53 meningiomas and 7 schwannomas treated with FSRS between October 2007 and February 2020. We administered a marginal dose of 6-7 Gy (mean 6.8 Gy) per fraction and delivered 3 fractions in 3 consecutive days. The median tumor volume was 6.31 cm3 (range 0.3-58.23 cm3). The mean minimum lesion-optic distance (MLOD) is 0.85 mm (range 0-3 mm). After mean follow-up period of 69.6 months (range 6.82-156.32 months; median 58.9 months), the tumor control rates at 1, 3, 5, 8 and 13 years were 98.3%, 93.4%, 90.60%, 88.4% and 88.4%, respectively. Four out of the 60 tumors (6.7%) experienced a transient volume increase after FSRS. None of the patients developed visual impairment related to radiation induced optic neuropathy (RION) after FSRS. In conclusion, FSRS offers an alternative treatment option in treating perioptic meningiomas and schwannomas with acceptable tumor control rates and good visual preservation in the present study.

Dosimetric comparison between RapidArc and HyperArc techniques in salvage stereotactic body radiation therapy for recurrent nasopharyngeal carcinoma.

BACKGROUND: To evaluate dosimetric differences of salvage irradiations using two commercially available volumetric modulated arc therapy (VMAT) stereotactic body radiation therapy (SBRT) techniques: RapidArc (RA) and HyperArc (HA), for recurrent nasopharyngeal carcinoma (NPC) after initial radiation therapy. METHODS: Ten patients with recurrent NPC status previously treated with radiation therapy were considered suitable candidates for salvage SBRT using VMAT approach. Two separate treatment plans were created with HA and RA techniques for each case, with dosimetric outcomes compared with respect to tumor target coverage and organs-at-risk (OARs) sparing. Furthermore, the cumulative radiobiological effects to the relevant OARs from the original radiotherapy to the respective salvage SBRT plans were analyzed in terms of biologically effective dose (BED). RESULTS: Treatment with HA exhibited similar target dose coverage as with RA, while delivering a higher mean dose to the targets. Using RA technique, the mean maximal doses to optic apparatus and the mean brain dose were reduced by 1 to 1.5 Gy, comparing to HA technique. The conformity index, gradient radius, and intermediate dose spillage in HA plans were significantly better than those in RA. With HA technique, the volume of brain receiving 12 Gy or more was reduced by 44%, comparing to RA technique. The cumulative BEDs to spinal cord and optic apparatus with RA technique were 1 to 2 Gy3 less than those with HA. HA technique significantly reduced the volume within body that received more than 100 Gy. CONCLUSIONS: With better dose distribution than RA while maintaining sufficient target dose coverage, HA represents an attractive salvage SBRT technique for recurrent NPC.

Hypothermia but not NMDA receptor antagonism protects against stroke induced by distal middle cerebral arterial occlusion in mice.

Excitotoxicity mediated by the N-methyl-D-aspartate receptor (NMDAR) is believed to be a primary mechanism of neuronal injury following stroke. Thus, many drugs and therapeutic peptides were developed to inhibit either the NMDAR at the cell surface or its downstream intracellular death-signaling cascades. Nevertheless, the majority of focal ischemia studies concerning NMDAR antagonism were performed using the intraluminal suture-induced middle cerebral arterial occlusion (MCAO) model, which produces a large cortical and subcortical infarct leading to hypothalamic damage and fever in experimental animals. Here, we investigated whether NMDAR antagonism by drugs and therapeutic peptides was neuroprotective in a mouse model of distal MCAO (dMCAO), which produces a small cortical infarct sparing the hypothalamus and other subcortical structures. For establishment of this model, mice were subjected to dMCAO under normothermic conditions or body-temperature manipulations, and in the former case, their brains were collected at 3-72 h post-ischemia to follow the infarct development. These mice developed cortical infarction 6 h post-ischemia, which matured by 24-48 h post-ischemia. Consistent with the hypothesis that the delayed infarction in this model can be alleviated by neuroprotective interventions, hypothermia strongly protected the mouse brain against cerebral infarction in this model. To evaluate the therapeutic efficacy of NMDAR antagonism in this model, we treated the mice with MK801, Tat-NR2B9c, and L-JNKI-1 at doses that were neuroprotective in the MCAO model, and 30 min later, they were subjected to 120 min of dMCAO either in the awake state or under anesthesia with normothermic controls. Nevertheless, NMDAR antagonism, despite exerting pharmacological effects on mouse behavior, repeatedly failed to show neuroprotection against cerebral infarction in this model. The lack of efficacy of these treatments is reminiscent of the recurrent failure of NMDAR antagonism in clinical trials. While our data do not exclude the possibility that these treatments could be effective at a different dose or treatment regimen, they emphasize the need to test drug efficacy in different stroke models before optimal doses and treatment regimens can be selected for clinical trials.

Isoflurane attenuates carbogen-induced blood-brain barrier disruption independent of body temperature in mice and rats.

Isoflurane protects the blood-brain barrier (BBB) against cerebral extravasation of Evans blue dye (EBD), a commonly used serum protein tracer, in animals subjected to BBB disruption. As such, it has been implicated as a therapeutic agent that can prevent brain edema and damage caused by a number of brain insults, including focal ischemia and subarachnoid hemorrhage. Recently, it has been shown that isoflurane inhibits the cerebral extravasation of EBD following ischemic stroke chiefly by inducing hypothermia, raising the intriguing possibility that isoflurane protected against other causes of BBB disruption also through hypothermia. To test this hypothesis, we subjected mice and rats to inhalation of 20-30% carbogen, an inducer of BBB disruption, in the presence or absence of isoflurane while measuring their rectal temperature. In mice, carbogen inhalation on its own decreased rectal temperature from 36.4 ± 0.4 to 26.2 ± 0.6°C over a period of 60 minutes, and under this condition, isoflurane had no additional effect on body temperature. Nevertheless, isoflurane protected against carbogen-induced cerebral extravasation of EBD. In addition, when the body temperature was maintained in the normothermic range using an automated heating pad, isoflurane remained protective against cerebral extravasation of EBD. In rats, isoflurane also protected against cerebral extravasation of EBD, while having no effect on plasma pH, electrolyte concentrations, or osmolarity. In conclusion, isoflurane protected against BBB disruption caused by carbogen inhalation in mice and rats, but unlike isoflurane-mediated protection against ischemic BBB disruption, the effect could not be explained by anesthesia-induced hypothermia.

Musashi-1 promotes stress-induced tumor progression through recruitment of AGO2.

Carcinomatous progression and recurrence are the main therapeutic challenges frequently faced by patients with refractory tumors. However, the underlined molecular mechanism remains obscure. Methods: We found Musashi-1 (MSI1) transported into cytosol under stress condition by confocal microscopy and cell fractionation. Argonaute 2 (AGO2) was then identified as a cytosolic binding partner of MSI1 by Mass Spectrametry, immunoprecipitation, and recombinant protein pull-down assay. We used RNA-IP to determine the MSI1/AGO2 associated regions on downstream target mRNAs. Finally, we overexpressed C-terminus of MSI1 to disrupt endogenous MSI1/AGO2 interaction and confirm it effects on tmor progression. Results: Malignant tumors exhibit elevated level of cytosolic Musashi-1 (MSI1), which translocates into cytosol in response to stress and promote tumor progression. Cytosolic MSI1 forms a complex with AGO2 and stabilize or destabilize its target mRNAs by respectively binding to their 3´ untranslated region or coding domain sequence. Both MSI1 translocation and MSI1/AGO2 binding are essential for promoting tumor progression. Blocking MSI1 shuttling by either chemical inhibition or point mutation attenuates the growth of GBM-xenografts in mice. Importantly, overexpression of the C-terminus of MSI1 disrupts endogenous MSI1/AGO2 interaction and effectively reduces stress-induced tumor progression. Conclusion: Our findings highlight novel molecular functions of MSI1 during stress-induced carcinomatous recurrence, and suggest a new therapeutic strategy for refractory malignancies by targeting MSI1 translocation and its interaction with AGOs.

Carbogen inhalation opens the blood-brain barrier in rats without causing long-term metabolic or neurological deficit.

The blood-brain barrier (BBB) prevents many drugs from entering the brain. Yet, conventional methods that open the BBB are technically demanding, poorly reversible, and can be associated with long-term adverse effects. In comparison, carbogen, which is introduced nearly a century ago as a treatment for psychiatric disorders, is easy to administer and readily available to many labs and hospitals. Here, we show that carbogen inhalation opened the BBB in rats, as indicated by the extravasation of an intravenous protein tracer. When the tracer was injected immediately or hours after carbogen inhalation, less tracer was detected in the rat brains, suggesting at least partial reversibility of this response after carbogen exhalation. Despite marked increase in BBB permeability, inhalation of carbogen for 30-90 min had no acute effect on the level of neuroinflammation or apoptosis in the brain, and had no long-term effect on body weight, food intake, locomotor activity, or learning and memory performance. Our study demonstrated that carbogen inhalation is a safe method to open the BBB.

MicroRNA-142-3p is involved in regulation of MGMT expression in glioblastoma cells.

BACKGROUND: Glioblastoma multiforme (GBM) is the most malignant brain tumor, and there is no effective treatment strategy. Patients with GBM have a median overall survival of only 14.6 months. Current treatment consists of safe and maximal surgical excision, followed by concurrent chemoradiotherapy and maintenance chemotherapy. There are several obstacles that hinder the effectiveness of this aggressive treatment. Temozolomide (TMZ) is an oral alkylating drug that acts through alkylating the O6 position of guanine in DNA that leads to cell death. However, the expression and enzymatic activity of the DNA repair protein MGMT limits the therapeutic benefit from treatment with TMZ. MGMT reduces the efficacy of alkylating drugs by removing the methyl or alkyl group from damaged O6-methylguanine. Expression levels of MGMT play an important role in the outcome of GBM patients. miRNAs are a group of small regulatory RNAs that control target gene expression by binding to mRNAs. miR-142-3p has been found to be an important factor in the development and maintenance of the oncogenic state. RESULTS: In this study, we sought to investigate whether miR-142-3p can regulate MGMT gene expression in GBM cells. Here, we show that miR-142-3p downregulates MGMT expression through binding to the 3'-UTR of MGMT mRNA, thus affecting protein translation. Responsiveness to TMZ was significantly enhanced after transfection with miR-142-3p. Overexpression of miR-142-3p also sensitized GBM cells to alkylating drugs. CONCLUSION: Above all, our findings demonstrate that miR-142-3p plays a critical role in regulating MGMT expression, has great potential for future clinical applications, and acts as a new diagnostic marker for this intractable disease.

Musashi-1 promotes chemoresistant granule formation by PKR/eIF2α signalling cascade in refractory glioblastoma.

Musashi-1 (MSI1), one of the RNA-binding proteins, is abundantly found not only in neural stem cells but also in several cancer tissues and has been reported to act as a positive regulator of cancer progression. Growing evidence indicates that PKR and eIF2α play pivotal roles in the stimulation of stress granule formation as well as in the subsequent translation modulation in response to stressful conditions; however, little is known about whether MSI1 is involved in this PKR/eIF2α cancer stem cell-enhancing machinery. In this study, we demonstrated that MSI1 promotes human glioblastoma multiforme (GBM) stem cells and enhances chemoresistance when exposed to sublethal stress. The overexpression of MSI1 leads to a protective effect in mitigating drug-induced cell death, thus facilitating the formation of chemoresistant stress granules (SGs) in response to arsenic trioxide (ATO) treatment. SG components, such as PKR and eIF2α, were dominantly activated and assembled, while ATO was engaged. The activated PKR and eIF2α contribute to the downstream enhancement of stem cell genes, thereby promoting the progression of GBM. The silencing of MSI1 or PKR both obviously withdrew the phenomena. Taken together, our findings indicate that MSI1 plays a leading role in stress granule formation that grants cancer stem cell properties and chemoresistant stress granules in GBM, in response to stressful conditions via the PKR/eIF2α signalling cascade.

Stem cell therapy on skin: Mechanisms, recent advances and drug reviewing issues.

Stem cell products and its clinical applications have been widely discussed in recent years, particularly when the Japanese "induced pluripotent stem cells" founder Dr. Yamanaka was awarded as Nobel Prize laureate in 2013. For decades, major progresses have been achieved in the stem cell biology field, and more and more evidence showed that skin stem cells are involved in the process of skin repair. Stem/progenitor cells of the epidermis are recognized to play the most essential role in the tissue regeneration of skin. In this review, we first illustrated basic stem cell characteristics and various stem cell subtypes resided in the skin. Second, we provided several literatures to elucidate how stem/progenitor cells collaborate in the process of skin repair with the evidence from animal model studies and in vitro experiments. Third, we also introduced several examples of skin cell products on the pharmaceutic market and the ongoing clinical trials aiming for unmet medical difficulties of skin. Last but not least, we summarized general reviewing concerns and some disputatious issues on dermatological cell products. With this concise review, we hope to provide further beneficial suggestions for the development of more effective and safer dermatological stem/progenitor cell products in the future.

Musashi-1 Enhances Glioblastoma Cell Migration and Cytoskeletal Dynamics through Translational Inhibition of Tensin3.

The RNA-binding protein Musashi-1 (MSI1) exerts essential roles in multiple cellular functions, such as maintenance of self-renewal and pluripotency of stem cells. MSI1 overexpression has been observed in several tumor tissues, including glioblastoma (GBM), and is considered as a well-established marker for tumor metastasis and recurrence. However, the molecular mechanisms by which MSI1 regulates cell migration are still undetermined. Here we reported that MSI1 alters cell morphology, promotes cell migration, and increases viscoelasticity of GBM cells. We also found that MSI1 directly binds to the 3'UTR of Tensin 3 (TNS3) mRNA, a negative regulator of cell migration, to inhibit its translation. Additionally, we identified that RhoA-GTP could be a potential regulator in MSI1/TNS3-mediated cell migration and morphological changes. In a xenograft animal model, high expression ratio of MSI1 to TNS3 enhanced GBM tumor migration. We also confirmed that MSI1 and TNS3 expressions are mutually exclusive in migratory tumor lesions, and GBM patients with MSI1high/TNS3low pattern tend to have poor clinical outcome. Taken together, our findings suggested a critical role of MSI1-TNS3 axis in regulating GBM migration and highlighted that the ratio of MSI1/TNS3 could predict metastatic and survival outcome of GBM patients.

Oncostatin M suppresses metastasis of lung adenocarcinoma by inhibiting SLUG expression through coordination of STATs and PIASs signalings.

Oncostatin M (OSM) is linked with multiple biological responses including growth and differentiation. Previous reports showed inhibitory effects of OSM in tumor progression while others showed promoting effects. The dual role of OSM in the development of various cancers is still unclear. We previously described OSM-mediated SLUG suppression, leading to repressed metastasis of lung adenocarcinoma (LAC) cells. However, the underlying mechanism remains elusive. Here, we showed that OSM suppresses SLUG express in LAC cells through a STAT1-dependent transcriptional inhibition. Knockdown of STAT1 reversed the OSM-suppressed SLUG expression and rescued the OSM-mediated inhibition of cell proliferation, migration, and invasion in vitro, as well as pulmonary metastasis in vivo. STAT1 suppressed SLUG transcription through binding to its promoter region in response to OSM. Furthermore, PIAS4, a co-repressor of STAT, and HDAC1 were able to bind to STAT1 on SLUG promoter region, resulting in reduced H3K9 acetylation and suppressed SLUG expression upon OSM treatment. In contrast, PIAS3 bound to activated STAT3, another effector of OSM, in response to OSM and blocked the binding of STAT3 to SLUG promoter region, preventing STAT3-dependent activation of SLUG transcription. Our findings suggested that OSM suppresses SLUG expression and tumor metastasis of LAC through inducing the inhibitory effect of the STAT1-dependent pathway and suppressing the activating effect of STAT3-dependent signaling. These results can serve as a scientific basis for the potential therapeutic intervention of OSM in cancer cells.

Musashi-1 regulates AKT-derived IL-6 autocrinal/paracrinal malignancy and chemoresistance in glioblastoma.

Glioblastoma multiform (GBM) is one of the most lethal human malignant brain tumors with high risks of recurrence and poor treatment outcomes. The RNA-binding protein Musashi-1 (MSI1) is a marker of neural stem/progenitor cells. Recent study showed that high expression level of MSI1 positively correlates with advanced grade of GBM, where MSI1 increases the growth of GBM. Herein, we explore the roles of MSI1 as well as the underlying mechanisms in the regulation of drug resistance and tumorigenesis of GBM cells. Our results demonstrated that overexpression of MSI1 effectively protected GBM cells from drug-induced apoptosis through down-regulating pro-apoptotic genes; whereas inhibition of AKT withdrew the MSI1-induced anti-apoptosis and cell survival. We further showed that MSI1 robustly promoted the secretion of the pro-inflammatory cytokine IL-6, which was governed by AKT activity. Autonomously, the secreted IL-6 enhanced AKT activity in an autocrine/paracrine manner, forming a positive feedback regulatory loop with the MSI1-AKT pathway. Our results conclusively demonstrated a novel drug resistance mechanism in GBM cells that MSI1 inhibits drug-induced apoptosis through AKT/IL6 regulatory circuit. MSI1 regulates both cellular signaling and tumor-microenvironmental cytokine secretion to create an intra- and intercellular niche for GBM to survive from chemo-drug attack.

Evaluating the consistency of location of the most severe acute skin reaction and highest skin dose measured by thermoluminescent dosimeter during radiotherapy for breast cancer.

We conducted this prospective study to evaluate whether the location of the most severe acute skin reaction matches the highest skin dose measured by thermoluminescent dosimeter (TLD) during adjuvant radiotherapy (RT) for patients with breast cancer after breast conservative surgery. To determine whether TLD measurement can reflect the location of the most severe acute skin reaction, 80 consecutive patients were enrolled in this prospective study. We divided the irradiated field into breast, axillary, inframammary fold, and areola/nipple areas. In 1 treatment session when obvious skin reaction occurred, we placed the TLD chips onto the 4 areas and measured the skin dose. We determined whether the highest measured skin dose area is consistent with the location of the most severe skin reaction. The McNemar test revealed that the clinical skin reaction and TLD measurement are more consistent when the most severe skin reaction occurred at the axillary area, and the p = 0.0108. On the contrary, TLD measurement of skin dose is less likely consistent with clinical observation when the most severe skin reaction occurred at the inframammary fold, breast, and areola/nipple areas (all the p > 0.05). Considering the common site of severe skin reaction over the axillary area, TLD measurement may be an appropriate way to predict skin reaction during RT.

Ginkgo biloba extract inhibits oxidized low-density lipoprotein (oxLDL)-induced matrix metalloproteinase activation by the modulation of the lectin-like oxLDL receptor 1-regulated signaling pathway in human umbilical vein endothelial cells.

BACKGROUND: The overexpression of matrix metalloproteinases (MMPs) induced by oxidized low-density lipoprotein (oxLDL) has been found in atherosclerotic lesions. Previous reports have identified that oxLDL, via the upregulation of lectin-like ox-LDL receptor 1 (LOX-1), modulates the expression of MMPs in endothelial cells. Ginkgo biloba extract (GbE), from Ginkgo biloba leaves, has often been considered as a therapeutic compound for cardiovascular and neurologic diseases. However, further investigation is needed to ascertain the probable molecular mechanisms underlying the antiatherogenic effects of GbE. The aim of this study was to investigate the effects of GbE on oxLDL-activated MMPs of human endothelial cells and to test the involvement of LOX-1 and protein kinase C (PKC)-α, extracellular signal-regulated kinase (ERK), and peroxisome proliferator-activated receptor-γ (PPAR-γ). METHODS: Human umbilical vein endothelial cells were stimulated with oxLDL, with or without GbE treatment. LOX-1 signaling and MMPs expression were tested by Western blotting or activity assay. Further, protein expression levels of PKC-α, ERK, nuclear factor-κB, and PPAR-γ were investigated by Western blotting. RESULTS: GbE inhibited the oxLDL-caused upregulation of MMP-1, MMP-2, and MMP-3. Pretreating with GbE reduced oxLDL-activated LOX-1 expression. Furthermore, pharmacologic inhibitors of free radicals, Ca(++), PKC, and GbE, inhibited the oxLDL-induced ERK and nuclear factor-κB activation. Lastly, GbE ameliorated the oxLDL-inhibited PPAR-γ function. CONCLUSIONS: Data obtained in this study indicate that GbE actives its protective effects by regulating the LOX-1-mediated PKC-α/ERK/PPAR-γ/MMP pathway, resulting in the suppression of reactive oxygen species formation and, ultimately, the reduction of MMPs expression in endothelial cells treated with oxLDL.