Clinical and image features: large-vessel vasculitis after granulocyte colony stimulating factor administration

BACKGROUND

Granulocyte colony stimulating factor (G-CSF) is known to cause vasculitis, mainly in the small vessels. Several cases of large-vessel vasculitis (LVV) caused by G-CSF have recently been reported in the literature; we retrospectively suspect that some cases of LVV in our institution were associated with administration of G-CSF.

PURPOSE

To evaluate the clinical and radiological findings in our cases and to compare them with those in previous reports.

MATERIAL AND METHODS

We retrospectively evaluated clinical and radiological findings in four cases of LVV that occurred after administration of G-CSF in our institution. We also reviewed papers on G-CSF-related LVV and compared their findings to ours.

RESULTS

G-CSF-related LVV occurred in patients aged > 50 years and more frequently in women. Most patients developed vasculitis within 15 days after the last administration. While 14/16 patients were symptomatic, the remaining two patients were asymptomatic and diagnosed incidentally. In all cases, laboratory inflammatory markers increased, but there were no autoantibodies that clearly indicated other autoimmune vasculitis. Computed tomography revealed elevated soft tissue density around the affected vessels.

CONCLUSION

LVV is among the potential adverse events of G-CSF administration. We should keep this outcome in mind when we interpret medical images of patients with previous G-CSF treatment history even if they are asymptomatic.

Japan Society of Gynecologic Oncology 2022 guidelines for uterine cervical neoplasm treatment

The Japan Society of Gynecologic Oncology (JSGO) Guidelines 2022 for the Treatment of Uterine Cervical Cancer are revised from the 2017 guideline. This guideline aimed to provide standard care for cervical cancer, indicate appropriate current treatment methods for cervical cancer, minimize variances in treatment methods among institutions, improve disease prognosis and treatment safety, reduce the economic and psychosomatic burden of patients by promoting the performance of appropriate treatment, and enhance mutual understanding between patients and healthcare professionals. The guidelines were prepared through the consensus of the JSGO Guideline Committee, based on a careful review of evidence gathered through the literature searches and the medical health insurance system and actual clinical practice situations in Japan. The guidelines comprise seven chapters and 5 algorithms. The main features of the 2022 revision are as follows: 1) added discussed points at the final consensus meeting; 2) revised the treatment methods based on the International Federation of Gynecology and Obstetrics 2018 staging system; 3) examined minimally invasive surgery based on Laparoscopic Approach to Cervical Cancer trial; 4) added clinical question (CQ) for treatments of rare histological types, gastric type, and small-cell neuroendocrine carcinoma; 5) added CQ for intensity-modulated radiation therapy; 6) added CQ for cancer genomic profiling test; and 7) added CQ for cancer survivorship. Each recommendation is accompanied by a classification of recommendation categories based on the consensus reached by the Guideline Committee members. Here, we present the English version of the JSGO Guidelines 2022 for the Treatment of Uterine Cervical Cancer.

Mechanism of Cell Death by Combined Treatment with an xCT Inhibitor and Paclitaxel: An Alternative Therapeutic Strategy for Patients with Ovarian Clear Cell Carcinoma

Ovarian clear cell carcinoma (OCCC) is a rare subtype of epithelial ovarian carcinoma that responds poorly to chemotherapy. Glutathione (GSH) is a primary antioxidant, which protects cells against reactive oxygen species (ROS). High levels of GSH are related to chemotherapeutic resistance. The glutamine/cystine transporter xCT is essential for intracellular GSH synthesis. However, whether xCT inhibition can overcome the resistance to chemotherapeutic agents in OCCC remains unclear. This study demonstrated that combined treatment with paclitaxel (PTX) and the xCT inhibitor sulfasalazine (SAS) significantly enhanced cytotoxicity more than the individual drugs did in OCCC cells. Treatment with PTX and SAS induced apoptosis more effectively than did individual drug treatments in the cells with significant generation of ROS. Moreover, combined treatment with PTX and SAS induced ferroptosis in the cells with low expression of glutathione peroxidase (GPx4), high levels of intracellular iron and significant lipid ROS accumulation. Therefore, our findings provide valuable information that the xCT inhibitor might be a promising therapeutic target for drug-resistant OCCC. The strategy of combined administration of PTX and SAS can potentially be used to treat OCCC and help to develop novel therapeutic methods.

Comparison of treatment outcomes between first-line chemotherapy with or without bevacizumab for advanced ovarian, fallopian tube, and primary peritoneal cancer (Tohoku gynecologic cancer unit: TGCU-RS001 study)

BACKGROUND

Outcomes with and without bevacizumab as first-line chemotherapy in Japanese-only ovarian cancer patients have not been reported. In this study, we report a retrospective study conducted at the Tohoku Gynecologic Cancer Unit.

PATIENTS AND METHODS

The study included 453 patients with stage III/IV ovarian, fallopian tube, and primary peritoneal cancer who received first-line platinum-based chemotherapy. The patients were divided into two groups: bevacizumab (168 patients) and without bevacizumab (285 patients). The primary endpoint was the rate of platinum-resistant recurrence and the secondary endpoints were the antitumor response, progression-free survival, overall survival, and adverse events.

RESULTS

The objective response rates for patients with measurable diseases treated with and without bevacizumab were 84.5% and 73.0%, respectively (P = 0.0066). Platinum-resistant recurrence in the groups treated with and without bevacizumab was noted in 31 (18.4%) and 111 (38.6%) patients, respectively (P < 0.0001). The median progression-free survival for the bevacizumab and without bevacizumab groups was 23 and 15 months, respectively (P = 0.0002), and the median overall survival was not reached and 49 months, respectively (P = 0.0005). Hypertension of grade 3 or higher was observed in 21 patients (12.5%) in the bevacizumab group (P < 0.001), and proteinuria was observed in 18 patients (10.7%) and 1 patient (0.3%) in the bevacizumab and without bevacizumab groups, respectively (P < 0.001). Intestinal perforation was observed in only one patient (0.6%) in the bevacizumab group.

CONCLUSION

Combination and maintenance with bevacizumab in primary chemotherapy for advanced ovarian, fallopian tube, and primary peritoneal cancer was effective in reducing platinum-resistant recurrence rates and prolonging progression-free and overall survival.

Impact of adjuvant chemotherapy on the overall survival of patients with resectable bulky small cell neuroendocrine cervical cancer: a JSGO-JSOG joint study

OBJECTIVE

The aim of this study was to review the clinicopathological characteristics of small cell neuroendocrine cervical cancer (SCNEC) and to identify the optimal treatment.

METHODS

The Japanese Society of Gynecologic Oncology conducted a retrospective cohort study of SCNECs enrolled in the Gynecological Tumor Registry of the Japan Society of Obstetrics and Gynecology between 2004 and 2015. All cases were modified and unified by International Federation of Gynecology and Obstetrics 2008 (Union for International Cancer Control 7th edition).

RESULTS

There were 822 registered patients diagnosed with SCNEC from 2004 to 2015 which comprised 1.1% (822/73,698) of all uterine cervical cancer cases. Rates of lymph-node and distant metastasis were significantly higher in T1b2 (38.9% and 13.7%, respectively) than T1b1 (14.2% and 4.4%, respectively) (p<0.01). In IB2 and T1bN1M0 SCNEC, the 5-year survival rate with surgery followed by chemotherapy was significantly higher than that with surgery followed by radiation therapy/concurrent chemoradiation therapy (p<0.01).

CONCLUSION

SNCEC tumors >4 cm in size had greater rates of lymph-node and distant metastasis when compared with tumors ≤4 cm. Adjuvant chemotherapy, rather than radiotherapy, may improve prognosis after surgery in T1bN1M0 SCNEC.

Impact of the glutathione synthesis pathway on sulfasalazine-treated endometrial cancer

Glutathione is an antioxidant that has an important role in chemotherapeutic drug resistance in cancer. Cysteine is synthesized from cystine and is transported into the cell via the xCT antiporter. Another pathway for synthesizing cysteine involves intracellular methionine. We determined whether targeting the xCT represents a promising strategy for the treatment of endometrial cancer and identified factors that predict efficacy of this treatment strategy. In uterine serous carcinoma (USC) cell lines, the combination of cisplatin and the xCT inhibitor, sulfasalazine, significantly inhibited cell growth compared with single-agent cisplatin or sulfasalazine. Sulfasalazine treatment significantly decreased intracellular glutathione levels and induced apoptosis when combined with cisplatin in USC cell lines. On the one hand, the effectiveness of combined cisplatin and sulfasalazine was not evident in endometrioid carcinoma. USC cell lines exhibited increased expression of xCT and decreased expression of cystathionine gamma lyase (CGL), which is an enzyme involved in the synthesis of cysteine from methionine. On the other hand, endometrioid carcinoma cell lines exhibited increased CGL expression or decreased xCT expression. These findings suggest that using a glutathione synthesis pathway-based approach for selecting subjects for sulfasalazine treatment may be an effective strategy for circumventing glutathione-related chemotherapeutic drug resistance in endometrial carcinoma.

Squamous cell carcinoma arising from a mature cystic teratoma of the ovary: Successful treatment with carboplatin, paclitaxel, and bevacizumab

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Squamous cell carcinoma arising from a mature cystic teratoma of the ovary is rare.

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The optimal treatment for this disease is unclear.

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We report a successfully treating case of SCC arising from MCT with carboplatin, paclitaxel, and bevacizumab.

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Bevacizumab might have been one of the treatment options for patients with advanced-stage of this disease.

Ovarian mature cystic teratomas (MCT) are usually benign. However, squamous cell carcinoma (SCC) develops in 0.17–2% of MCT. Because of its low frequency, the optimal treatment for this disease is unclear. We present a case of SCC arising from MCT. Our patient was a 30-year-old nulliparous woman complaining of right lower abdominal pain, who was referred to our hospital for a pelvic solid mass with suspected malignant ovarian tumor. A diagnosis of SCC arising from MCT was suspected based on the elevation in SCC antigen and the imaging. After surgery to remove the tumor, the diagnosis was confirmed based on the pathology. Although the surgery by radical cytoreduction was optimal, the tumor showed early recurrence. Therefore, we administrated combination chemotherapy, consisting of carboplatin, paclitaxel, and bevacizumab, followed by maintenance therapy with bevacizumab. Response to the chemotherapy regimen was complete and the patient was alive with no evidence of recurrence for 45 months after starting the initial surgery. We discuss the clinical characteristics of the malignant transformation of MCT and the treatment of SCC arising from MCT.

xCT inhibitor sulfasalazine depletes paclitaxel-resistant tumor cells through ferroptosis in uterine serous carcinoma

Glutathione (GSH) is a primary antioxidant that protects cells against reactive oxygen species (ROS), and high levels of GSH promote cancer cell survival and resistance to chemotherapy. The glutamine transporter xCT is essential for the intracellular synthesis of GSH, whereby xCT determines the intracellular redox balance. However, whether xCT inhibition can overcome GSH-mediated resistance to chemotherapeutic agents in uterine serous carcinoma (USC) remains unclear. Thus, the present study investigated the effect of the xCT inhibitor, sulfasalazine (SAS) on cytotoxicity in paclitaxel-sensitive and -resistant USC cell lines. The molecular mechanism by which SAS induces ferroptotic cell death in paclitaxel-resistant cells was assessed. The results of the cytotoxicity assay demonstrated that SAS was more cytotoxic in paclitaxel-resistant cells compared with in -sensitive cells; however, paclitaxel cytotoxicity was not enhanced in either of the USC cell lines. Immunoblotting analysis and the cell death assays performed using ferroptosis inhibitors indicated that SAS-mediated cell death was induced through ferroptosis, and not apoptosis, in paclitaxel-resistant cells. Furthermore, ROS production was increased in paclitaxel-resistant but not in -sensitive cells, even at low SAS concentration, and JNK was activated, which is a downstream target in the Ras signaling pathway. Knockdown of JNK reversed the inhibitory effect of SAS on cell proliferation and cell death. The synthetic lethal interaction between ROS accumulation and Ras effector JNK activation may be critical for enhancing the sensitivity to ferroptotic cell death mediated by xCT inhibitor, SAS. Taken together, the results of the present study suggest that xCT inhibition may be an effective treatment for patients with recurrent paclitaxel-resistant USC.

Successful management of cutaneous lymphangitis carcinomatosa arising from cervical cancer with paclitaxel-cisplatin and bevacizumab combination therapy: a case report and review of the literature

Background

Globally, cervical cancer is the fourth most common cancer in women. Here, we report a case of cutaneous lymphangitis carcinomatosa arising from cervical cancer, an extremely rare and treatment-resistant condition.

Case presentation

A 64-year-old Japanese woman presented with genital bleeding. She was diagnosed as having stage IB1 squamous cell cervical cancer and subsequently treated with radiotherapy. Approximately 2 years after the curative radiotherapy, she developed itching, skin rash, and small nodules on her left femoral and pubic area. Slight ¹⁸F-fluorodeoxyglucose uptake was detected at her left femoral skin on positron emission tomography with computed tomography. A histopathological examination was performed on a biopsy sample from an erythematous macule on her left femoral skin and vulva. Consequently, she was diagnosed as having cutaneous lymphangitis carcinomatosa arising from cervical cancer. Paclitaxel (135 mg/m²), cisplatin (50 mg/m²), and bevacizumab (15 mg/kg) combination therapy was administered every 21 days. Both itching and rash improved after three treatment cycles. After the completion of six cycles, skin erythema in the femoral and vulval area disappeared completely. Our patient experienced a 25-month symptom-free interval after the last chemotherapy session.

Conclusion

Our findings suggest that combination chemotherapy plus bevacizumab is an effective therapeutic option in patients with cutaneous lymphangitis carcinomatosa arising from cervical cancer.

Metabolomic analysis of uterine serous carcinoma with acquired resistance to paclitaxel

INTRODUCTION

Uterine serous carcinoma (USC) is more aggressive than other subtypes of endometrial carcinoma and is associated with a poor prognosis. We analyzed the metabolomic profile of USC with acquired resistance to paclitaxel.

RESULTS

Glutathione (GSH) concentration in PTX-1 cells was higher than in USPC-1 cells. In addition, GSH concentration in the USPC-1 cells increased after treatment with paclitaxel but was unchanged in PTX-1 cells. Glucose-6-phosphate (G6P) and ribose-5-phosphate (R5P) concentrations in PTX-1 cells were higher than those in USPC-1 cells. G6P concentration in the USPC-1 cells was unchanged after treatment with paclitaxel, while it decreased in PTX-1 cells.

CONCLUSION

Our results indicate that increased GSH and glucose metabolism may be related to acquiring resistance to paclitaxel in USC and thus may be targets for anti-USC therapy.

MATERIALS AND METHODS

We compared metabolic profiles and reactions to paclitaxel in both a wild type USC cell line (USPC-1) and PTX-1, a cell line derived from USPC-1 which acquired paclitaxel resistance, using a capillary electrophoresis CE-MS/MS system.

Abstract 383: Metabolomic analysis of uterine serous carcinoma with acquired resistance to paclitaxel

Introduction: Uterine serous carcinoma (USC) is more aggressive than other subtypes of endometrial carcinoma and is associated with a poor prognosis. We analyzed the metabolomic profile of USC with acquired resistance to paclitaxel.

Method: We compared metabolic profiles and reactions to paclitaxel in both a wild-type USC cell line (USPC-1) and PTX-1, a cell line derived from USPC-1 that acquired paclitaxel resistance, using a capillary electrophoresis CE-MS/MS system.

Results: Glutathione (GSH) concentration in PTX-1 cells was higher than in USPC-1 cells. In addition, GSH concentration in the USPC-1 cells increased after treatment with paclitaxel but was unchanged in PTX-1 cells. Glucose-6-phosphate (G6P) and ribose-5-phosphate (R5P) concentrations in PTX-1 cells were higher than those in USPC-1 cells. G6P concentration in the USPC-1 cells was unchanged after treatment with paclitaxel, while it decreased in PTX-1 cells.

Conclusion: Our results indicate that increased GSH and glucose metabolism may be related to acquiring resistance to paclitaxel in USC and thus may be targets for anti-USC therapy.

Citation Format: Manabu Seino, Tsuyoshi Ohta, Hirotsugu Sakaki, Takeshi Sudo, Satoru Nagase. Metabolomic analysis of uterine serous carcinoma with acquired resistance to paclitaxel [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 383.

Tumor lysis syndrome associated with docetaxel and carboplatin in a case with recurrent endometrial cancer

Tumor lysis syndrome (TLS) is an oncological life-threatening complication characterized by hyperuricemia, hyperphosphatemia, and hyperkalemia, which can lead to acute renal failure, cardiac arrhythmias, cardiac arrest and seizures. Although TLS is a rare complication in patients with non-hematological malignancy, the mortality rate of TLS in solid tumors is higher than that in hematological malignancies. Acute renal injury is the most common cause of mortality associated with TLS in solid tumors. We report a case of TLS following chemotherapy for a recurrent uterine serous carcinoma. In this case, we speculated that the cause of death might be a pulmonary tumor embolism caused by TLS.

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Tumor lysis syndrome (TLS) is an oncological life-threatening complication.

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The mortality rate of TLS in solid tumors is high, acute renal injury being the most common cause.

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We report a case of TLS following chemotherapy for a recurrent uterine serous carcinoma.

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We speculated that the cause of death might be a pulmonary tumor embolism caused by TLS.

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Clinicians need to assess the risk of TLS before chemotherapy, which should be given to high risk patient appropriately.

The novel JNK inhibitor AS602801 inhibits cancer stem cells in vitro and in vivo

A phase 2 clinical trial investigating the efficacy and safety of AS602801, a newly developed JNK inhibitor, in the treatment of inflammatory endometriosis is complete. We are now examining whether AS602801 acts against human cancer cells in vitro and in vivo. In vitro, AS602801 exhibited cytotoxicity against both serum-cultured non-stem cancer cells and cancer stem cells derived from human pancreatic cancer, non-small cell lung cancer, ovarian cancer and glioblastoma at concentrations that did not decrease the viability of normal human fibroblasts. AS602801 also inhibited the self-renewal and tumor-initiating capacity of cancer stem cells surviving AS602801 treatment. Cancer stem cells in established xenograft tumors were reduced by systemic administration of AS602801 at a dose and schedule that did not adversely affect the health of the tumor-bearing mice. These findings suggest AS602801 is a promising anti-cancer stem cell agent, and further investigation of the utility of AS602801 in the treatment of cancer seems warranted.

Activation of estrogen receptor α by estradiol and cisplatin induces platinum-resistance in ovarian cancer cells

Activation of Estrogen receptor (ER) α (α) promotes cell growth and influences the response of cancer cell to chemotherapeutic agents. However, the mechanism by which ERα activation antagonizes cells to chemotherapy-induced cytotoxicity remains unclear. Here, we investigated the effect of cisplatin on ERα activation. In addition, we examined whether down-regulation of ERα modulate cisplatin-mediated cytotoxicity using 2 human ovarian cancer cells (Caov-3 and Ovcar-3) transduced with ERα short hairpin RNA (shRNA). The proliferation assay showed that 17β-estradiol (E2) induced cell proliferation via activation of Akt and extracellular signal-regulated kinase (ERK) cascades, while shRNA mediated downregulation of ERα inhibited the cell proliferation. Immunoblot analysis revealed that cisplatin induced the phosphorylation of ERα at serine 118 via ERK cascade. Luciferase assay showed that cisplatin increases transcriptional activity of estrogen-responsive element (ERE). The E2-stimulated ERα activation attenuated cisplatin-induced cytotoxicity. Meanwhile, down-regulation of ERα inhibited E2-induced protective effect on cisplatin toxicity as determined by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assays. Moreover, Pretreatment with E2 followed by cisplatin decreased the expression of cleaved PARP, and increased the expression of anti-apoptotic protein Bcl-2. Collectively, our findings suggest that activation of ERα by E2 and cisplatin can induce platinum-resistance by increasing the expression of anti-apoptotic protein in ovarian cancer cells. Therefore, our findings provide valuable information that ERα might be a promising therapeutic target for platinum-resistant ovarian cancer.

JNK suppression of chemotherapeutic agents-induced ROS confers chemoresistance on pancreatic cancer stem cells

Chemoresistance associated with cancer stem cells (CSCs), which is now being held responsible for the pervasive therapy resistance of pancreatic cancer, poses a major challenge to the successful management of this devastating malignancy. However, the molecular mechanism underlying the marked chemoresistance of pancreatic CSCs remains largely unknown. Here we show that JNK, which is upregulated in pancreatic CSCs and contributes to their maintenance, is critically involved in the resistance of pancreatic CSCs to 5-fluorouracil (5-FU) and gemcitabine (GEM). We found that JNK inhibition effectively sensitizes otherwise chemoresistant pancreatic CSCs to 5-FU and GEM. Significantly, JNK inhibition promoted 5-FU- and GEM-induced increase in intracellular reactive oxygen species (ROS), and scavenging intracellular ROS by use of N-acetylcysteine impaired JNK inhibition-mediated promotion of the cytotoxicity of 5-FU and GEM. Our findings thus suggest that JNK may contribute to the chemoresistance of pancreatic CSCs through prevention of chemotherapeutic agents-induced increase in intracellular ROS. Our findings also suggest that JNK inhibition combined with 5-FU- and/or GEM-based regimens may be a rational therapeutic approach to effectively eliminate pancreatic CSCs.

GSKJ4, A Selective Jumonji H3K27 Demethylase Inhibitor, Effectively Targets Ovarian Cancer Stem Cells

BACKGROUND/AIM

Global increase in the trimethylation of histone H3 at lysine 27 (H3K27me3) has been associated with the differentiation of normal stem cells and cancer cells, however, the role of H3K27me3 in the control of cancer stem cells (CSCs) remains poorly understood. We investigated the impact of increased H3K27me3 on CSCs using a selective H3K27 demethylase inhibitor GSKJ4.

MATERIALS AND METHODS

The effect of GSKJ4 on the viability as well as on the self-renewal and tumor-initiating capacity of CSCs derived from the A2780 human ovarian cancer cell line was examined.

RESULTS

GSKJ4 induced cell death in A2780 CSCs at a concentration non-toxic to normal human fibroblasts. GSKJ4 also caused loss of self-renewal and tumor-initiating capacity of A2780 CSCs surviving GSKJ4 treatment.

CONCLUSION

Our findings suggest that H3K27 methylation may have an inhibitory role in the maintenance of CSCs and that GSKJ4 may represent a novel class of CSC-targeting agents.

Time-staggered inhibition of JNK effectively sensitizes chemoresistant ovarian cancer cells to cisplatin and paclitaxel

Ovarian cancer is the most lethal gynecological malignancy, for which platinum- and taxane-based chemotherapy plays a major role. Chemoresistance of ovarian cancer poses a major obstacle to the successful management of this devastating disease; however, effective measures to overcome platinum and taxane resistance are yet to be established. In the present study, while investigating the mechanism underlying the chemoresistance of ovarian cancer, we found that JNK may have a key role in the resistance of ovarian cancer cells to cisplatin and paclitaxel. Importantly, whereas simultaneous application of a JNK inhibitor and either of the chemotherapeutic agents had contrasting effects for cisplatin (enhanced cytotoxicity) and paclitaxel (decreased cytotoxicity), JNK inhibitor treatment prior to chemotherapeutic agent application invariably enhanced the cytotoxicity of both drugs, suggesting that the basal JNK activity is commonly involved in the chemoresistance of ovarian cancer cells to cisplatin and paclitaxel in contrast to drug‑induced JNK activity which may have different roles for these two drugs. Furthermore, we confirmed using non-transformed human and rodent fibroblasts that sequential application of the JNK inhibitor and the chemotherapeutic agents did not augment their toxicity. Thus, our findings highlight for the first time the possible differential roles of the basal and induced JNK activities in the chemoresistance of ovarian cancer cells and also suggest that time‑staggered JNK inhibition may be a rational and promising strategy to overcome the resistance of ovarian cancer to platinum- and taxane-based chemotherapy.

Targeting the facilitative glucose transporter GLUT1 inhibits the self-renewal and tumor-initiating capacity of cancer stem cells

Increased glucose metabolism is now recognized as an emerging hallmark of cancer. Recent studies have shown that glucose metabolism is even more active in cancer stem cells (CSCs), a rare population of cancer cells with the capacity to self-renew and initiate tumors, and that CSCs are dependent on glycolysis for their survival/growth. However, the role of glucose metabolism in the control of their self-renewal and tumor-initiating capacity per se still remains obscure. Moreover, much remains unknown as to which of the numerous molecules involved in the glucose metabolism is suitable as a target to control CSCs. Here we demonstrate that the facilitative glucose transporter GLUT1 is essential for the maintenance of pancreatic, ovarian, and glioblastoma CSCs. Notably, we found that WZB117, a specific GLUT1 inhibitor, could inhibit the self-renewal and tumor-initiating capacity of the CSCs without compromising their proliferative potential in vitro. In vivo, systemic WZB117 administration inhibited tumor initiation after implantation of CSCs without causing significant adverse events in host animals. Our findings indicate GLUT1-dependent glucose metabolism has a pivotal role not only in the growth and survival of CSCs but also in the maintenance of their stemness and suggest GLUT1 as a promising target for CSC-directed cancer therapy.

Abstract 2228: Requirement of JNK signaling for self-renewal and tumor-initiating capacity of ovarian cancer stem cells

Background/Aim: Activation of the c-JUN N-terminal kinase (JNK) signaling pathway has been associated with poor survival of patients with ovarian cancer, but the role(s) and significance of JNK signaling in ovarian cancer cells remain poorly understood. Here in this study, we aimed to investigate the role of JNK specifically in ovarian cancer stem cells (CSCs).

Materials and Methods: The effect of JNK inhibition on the self-renewal (CSC marker expression, sphere-forming ability) and tumor-initiating capacity was examined in CSCs derived from A2780 human ovarian cancer cell line. JNK inhibition was achieved either pharmacologically or genetically by use of RNA interference.

Results: Both pharmacological and genetic targeting of JNK resulted in loss of self-renewal and tumor-initiating capacity of A2780 CSCs.

Conclusion: Our findings demonstrate, to our knowledge for the first time, that JNK has a pivotal role in the maintenance of ovarian CSCs.

Citation Format: Manabu Seino, Masashi Okada, Keita Shibuya, Shizuka Seino, Shuhei Suzuki, Hiroyuki Takeda, Tsuyoshi Ohta, Hirohisa Kurachi, Kiyoshi Ito, Satoru Nagase, Chifumi Kitanaka. Requirement of JNK signaling for self-renewal and tumor-initiating capacity of ovarian cancer stem cells. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 2228. doi:10.1158/1538-7445.AM2015-2228

Targeting the K-Ras--JNK axis eliminates cancer stem-like cells and prevents pancreatic tumor formation

Cancer cells with self-renewal and tumor-initiating capacity, either quiescent (cancer stem cells, CSCs) or proliferating (cancer stem-like cells, CSLCs), are now deemed responsible for the pervasive therapy resistance of pancreatic cancer, one of the deadliest human cancers characterized by high prevalence of K-Ras mutation. However, to date, much remains unknown how pancreatic CSCs/CSLCs are regulated. Here we show that the K-Ras – JNK axis plays a pivotal role in the maintenance of pancreatic CSCs/CSLCs. In vitro inhibition of JNK, either pharmacological or genetic, caused loss of the self-renewal and tumor-initiating capacity of pancreatic CSLCs. Importantly, JNK inhibition in vivo via systemic JNK inhibitor administration, which had no discernible effect on the general health status of mice, efficiently depleted the CSC/CSLC population within pre-established pancreatic tumor xenografts. Furthermore, knockdown of K-Ras in pancreatic CSLCs with K-Ras mutation led to downregulation of the JNK pathway as well as in loss of self-renewal and tumor-initiating capacity. Together, our findings suggest that pancreatic CSCs/CSLCs are dependent on K-Ras activation of JNK and also suggest that the K-Ras – JNK axis could be a potential target in CSC/CSLC-directed therapies against pancreatic cancer.

Differential contribution of ROS to resveratrol-induced cell death and loss of self-renewal capacity of ovarian cancer stem cells

BACKGROUND/AIM

Cancer stem cells (CSCs) are considered to contribute to the poor prognosis of ovarian cancer as a major cause of fatal recurrence. Identification of effective measures to eliminate ovarian CSCs through induction of cell death and/or loss of self-renewal capacity would, therefore, be key to successful management of ovarian cancer.

MATERIALS AND METHODS

The effects of resveratrol on the viability and self-renewal capacity of CSCs derived from A2780 human ovarian cancer cells were examined. The involvement of reactive oxygen species (ROS) was also investigated.

RESULTS

At a non-toxic to normal human fibroblasts concentration, resveratrol effectively killed ovarian CSCs independently of ROS, while ROS-dependently impaired the self-renewal capacity of ovarian CSCs that survived resveratrol treatment.

CONCLUSION

Our findings not only shed light on a novel mechanism of action for resveratrol but also suggest that resveratrol, or its analogs, may be useful for CSC-directed therapy against ovarian cancer.

Requirement of JNK signaling for self-renewal and tumor-initiating capacity of ovarian cancer stem cells

BACKGROUND/AIM

Activation of the c-JUN N-terminal kinase (JNK) signaling pathway has been associated with poor survival of ovarian cancer patients, but the role(s) and significance of JNK signaling in ovarian cancer cells remain poorly understood. In the present study, we aimed to investigate the role of JNK specifically in ovarian cancer stem cells (CSCs).

MATERIALS AND METHODS

The effect of JNK inhibition on the self-renewal (CSC marker expression, sphere-forming ability) and tumor-initiating capacity was examined in CSCs derived from the A2780 human ovarian cancer cell line. JNK inhibition was achieved either pharmacologically or genetically by use of RNA interference.

RESULTS

Both pharmacological and genetic targeting of JNK resulted in loss of self-renewal and tumor-initiating capacity of A2780 CSCs.

CONCLUSION

Our findings demonstrate, to our knowledge for the first time, that JNK has a pivotal role in the maintenance of ovarian CSCs.

High levels of Wilms' tumor 1 (WT1) expression were associated with aggressive clinical features in ovarian cancer

AIM

The aim of the present study was to evaluate the correlation between WT1 expression levels and clinical features, to investigate the prognostic value of WT1 expression and to use lentiviral constructs to examine whether overexpression of WT1 affects cell proliferation and invasion in ovarian cancer patients.

MATERIALS AND METHODS

Real-time quantitative PCR (qPCR) methods were employed to analyze WT1 expression levels in clinical samples from 63 patients with ovarian cancer. The correlation between the copy number of WT1 mRNA and clinical variables was analyzed.

RESULTS

The median copy number of WT1 mRNA was 53.94 (range=2.135-32,257) in all subjects and WT1 expression levels were found significantly increased in patients with a higher stage cancer (p<0.05), lymphnode (p<0.001) and omentum metastasis (p<0.001), as well as ascites production (p<0.05), compared to patients lacking these clinical variables. No significant difference in WT1 expression levels were observed between patients with and without recurrence. The median disease-free survival time in patients with low WT1 expression levels was significantly longer (p=0.038) than that in patients with high WT1 expression. However, overall survival curves showed no statistically significant (p=0.457) differences between patients with high- and low-WT1 expression levels. An in vitro study revealed that WT1 over-expression enhanced cell proliferation and invasion in ovarian cancer cells transduced with lentiviral constructs.

CONCLUSION

Using qPCR, we found that high levels of WT1 expression correlated with aggressive clinical features in ovarian cancer. High WT1 expression may impact on median disease-free survival in ovarian cancer.

JNK contributes to temozolomide resistance of stem-like glioblastoma cells via regulation of MGMT expression

While elimination of the cancer stem cell population is increasingly recognized as a key to successful treatment of cancer, the high resistance of cancer stem cells to conventional chemoradiotherapy remains a therapeutic challenge. O6-methylguanine DNA methyltransferase (MGMT), which is frequently expressed in cancer stem cells of glioblastoma, has been implicated in their resistance to temozolomide, the first-line chemotherapeutic agent against newly diagnosed glioblastoma. However, much remains unknown about the molecular regulation that underlies MGMT expression and temozolomide resistance of glioblastoma cancer stem cells. Here, we identified JNK as a novel player in the control of MGMT expression and temozolomide resistance of glioblastoma cancer stem cells. We showed that inhibition of JNK, either pharmacologically or by RNA interference, in stem-like glioblastoma cells derived directly from glioblastoma tissues reduces their MGMT expression and temozolomide resistance. Importantly, sensitization of stem-like glioblastoma cells to temozolomide by JNK inhibition was dependent on MGMT expression, implying that JNK controls temozolomide resistance of stem-like glioblastoma cells through MGMT expression. Our findings suggest that concurrent use of JNK inhibitors with temozolomide may be a rational therapeutic approach to effectively target the cancer stem cell population in the treatment of glioblastoma.

Specific role of JNK in the maintenance of the tumor-initiating capacity of A549 human non-small cell lung cancer cells

Deregulation of c-Jun NH2-terminal kinase (JNK) signaling is now increasingly reported in a variety of human malignancies. Non-small cell lung cancer (NSCLC) is among such human malignancies with aberrant JNK activation; yet the exact role(s) of JNK deregulation in NSCLC biology, in particular in vivo, remains unclear. Here, we demonstrated a specific role of JNK in the control of the tumor-initiating capacity of A549 cells derived from human lung adenocarcinoma, a major subtype of NSCLC. Despite its potent inhibitory activity on A549 cell growth in vitro, SP600125, a reversible JNK inhibitor, failed to inhibit the growth of pre-established A549 xenografts in vivo when systemically administered. Nevertheless, the same SP600125 treatment caused a marked reduction in the tumor-initiating population within the A549 tumors, suggesting that JNK may be specifically required in vivo for the maintenance of the tumor-initiating population of tumor cells rather than for proliferation and survival of the entire cell population. Furthermore, A549 cells either pre-treated with SP600125 or transiently transfected with siRNAs against the JNK genes in vitro showed substantially reduced ability to initiate tumor formation upon implantation into nude mice, implying that the cell intrinsic JNK activity of A549 cells is essential for the maintenance of their tumor-initiating capacity. To our knowledge, this is the first demonstration that JNK is involved in the control of the tumor-initiating capacity of NSCLC cells. Our findings also give rise to an intriguing possibility that therapies targeting JNK could contribute to prevention of relapse and/or metastasis of NSCLC through elimination of tumor-initiating cells.

Chronic Effects of Norepinephrine and Vasopressin on Urinary Prostaglandin E and Kallikrein Excretions in Conscious Rats

To assess in vivo functional interactions of vasopressor substances, norepinephrine and vasopressin, with renal prostaglandins and kallikrein-kinin system which are responsible for the vasodepressor mechanism in the kidney, we evaluated chronic effects of norepinephrine (1.8 mg/kg/day ip) and vasopressin (7.2 U/kg/day ip) on urinary prostaglandin E excretion and urinary kallikrein excretion in conscious rats. Both norepinephrine and vasopressin induced a sustained increase in systolic blood pressure. Norepinephrine induced slight but significant increases in urinary prostaglandin E excretion and urinary kallikrein excretion which were sustained for up to 6 days. Vasopressin induced a marked increase in urinary prostaglandin E excretion which was sustained for up to 6 days, whereas it induced a sustained decrease in urinary kallikrein excretion. Circulating angiotensin II levels was not changed by norepinephrine, but was decreased by vasopressin. These results indicate that renal prostaglandin E may not correlate with renal kallikrein-kinin and renin-angiotensin system in the responses to norepinephrine and vasopressin, and that vasopressin may be a more potent stimulator of the synthesis or release of renal prostaglandin E.

Contrasting effects of zonisamide and acetazolamide on amygdaloid kindling in rats

PURPOSE

Zonisamide (ZNS) and acetazolamide (AZM) are two antiepileptic drugs (AEDs) that differ in clinical efficacy. To elucidate the mechanisms of action of these compounds, we investigated their therapeutic and prophylactic effects in rats by using a kindling model of partial epilepsy.

METHODS

Electrodes were implanted into the left amygdala of adult male Wistar rats. The animals were stimulated at the afterdischarge threshold until five stage 5 seizures were induced. The generalized seizure threshold was then determined. Therapeutic effects were examined in rats manifesting successive convulsions with near-threshold stimulation. To test prophylactic effects, drugs were administered intraperitoneally before daily kindling stimulation until the animal had a stage 5 seizure or reached day 18.

RESULTS

ZNS (10-40 mg/kg; n=6) suppressed kindled seizures in a dose-dependent manner. Repeated administration for 7 days produced tolerance to anticonvulsive effects. AZM (25-200 mg/kg; n=7) showed limited therapeutic effect, alleviating only the clonic convulsion in stage 5 seizures and reducing afterdischarge duration. Secondary generalization was not significantly suppressed during repeated treatment (50-200 mg/kg; n=6). ZNS, 25 or 40 mg/kg (n=8), significantly retarded seizure development; 15.0 or 17.0 daily stimulations were required to produce a stage 5 seizure. AZM, 50-200 mg/kg (n=6), also retarded seizure development, with 14.0-14.8 stimulations required.

CONCLUSIONS

ZNS exhibited modest therapeutic and prophylactic effects, whereas AZM showed mainly prophylactic effects. Hypotheses are presented that may explain the mechanisms of action of these drugs.

Activation of the dorsal premotor cortex and pre-supplementary motor area of humans during an auditory conditional motor task

Using functional magnetic resonance imaging (fMRI), we measured regional blood flow to examine which motor areas of the human cerebral cortex are preferentially involved in an auditory conditional motor behavior. As a conditional motor task, randomly selected 330 or 660 Hz tones were presented to the subjects every 1. 0 s. The low and high tones indicated that the subjects should initiate three successive opposition movements by tapping together the right thumb and index finger or the right thumb and little finger, respectively. As a control task, the same subjects were asked to alternate the two opposition movements, in response to randomly selected tones that were presented at the same frequencies. Between the two tasks, MRI images were also scanned in the resting state while the tones were presented in the same way. Comparing the images during each of the two tasks with images during the resting state, it was observed that several frontal motor areas, including the primary motor cortex, dorsal premotor cortex (PMd), supplementary motor area (SMA), and pre-SMA, were activated. However, preferential activation during the conditional motor task was observed only in the PMd and pre-SMA of the subjects' left (contralateral) frontal cortex. The PMd has been thought to play an important role in transforming conditional as well as spatial visual cues into corresponding motor responses, but our results suggest that the PMd along with the pre-SMA are the sites where more general and extensive sensorimotor integration takes place.

Electrical stimulation of the contralateral mesial temporal structure induces an ipsilateral seizure pattern in mesial temporal lobe epilepsy

PURPOSE

We examined the mode of seizure development induced by electrical stimulation in patients with mesial temporal lobe epilepsy.

METHODS

Of 25 patients undergoing intracranial EEG evaluation and electrical stimulation ipsilateral to the presumed site of habitual seizure origin, 17 patients had additional stimulation studies on the contralateral temporal lobe.

RESULTS

Fourteen of the 25 patients had seizures induced with ipsilateral stimulation, and two of the 17 patients had seizures with contralateral stimulation. Seizures induced by ipsilateral stimulation started in the ipsilateral temporal lobe, whereas those induced by contralateral stimulation originated from the ipsilateral temporal lobe structure and were identical to the habitual seizures.

CONCLUSIONS

Electrical stimulation of the temporal lobe structure opposite the site of habitual seizure origin is said to induce a seizure rarely. However, according to our preliminary results, if contralateral stimulation elicits a habitual seizure in the ipsilateral temporal lobe, it might be considered additional confirmatory evidence of seizure lateralization.

Photosensitive epilepsies and pathophysiologic mechanisms of the photoparoxysmal response

OBJECTIVE

To identify the pathophysiologic mechanisms of the photoparoxysmal response (PPR) in various photosensitive epilepsy syndromes, and to discuss the relation between these pathophysiologic mechanisms and the classification of epilepsies and epileptic syndromes.

BACKGROUND

The authors found two types of pathophysiologic mechanisms of PPRs (wavelength-dependent PPRs and quantity-of-light-dependent PPRs) in patients with idiopathic generalized epilepsy and hereditary dentatorubral-pallidoluysian atrophy.

METHODS

Intermittent photic stimulation with wavelength-specific optical filters was performed in photosensitive epileptic patients: six patients had severe myoclonic epilepsy in infancy (SMEI), eight had localization-related epilepsy (LRE), and seven had symptomatic generalized epilepsy (SGE).

RESULTS

Four of the six photosensitive SMEI patients had quantity-of-light-dependent PPRs. Five of the eight photosensitive LRE patients had wavelength-dependent PPRs. Four of the seven photosensitive SGE patients had wavelength-dependent PPRs, and two had quantity-of-light-dependent PPRs.

CONCLUSIONS

The type of pathophysiologic mechanism for eliciting PPRs by low-luminance photic stimulation was closely related to the classification of the epilepsy syndrome.

Wavelength dependence of photoparoxysmal responses in photosensitive patients with epilepsy

PURPOSE

We tried to specify the relation between the photoparoxysmal response (PPR) and the wavelength spectra of flashing light in various photosensitive epileptic syndromes in the physiologic state.

METHODS

Intermittent photic stimulation (IPS) by a Grass PS22 photic stimulator was performed with wavelength-specific optical filters in photosensitive patients with epilepsy (idiopathic generalized epilepsy, IGE; hereditary dentatorubral-pallidoluysian atrophy, DRPLA) and photosensitive subjects without epilepsy.

RESULTS

Five of 19 normal trichromat patients with IGE and an IGE patient with deuteranomaly showed wavelength-dependent PPRs. The wavelength-dependent PPRs were elicited only by IPS containing wavelength spectra approximately 700 nm in the normal trichromat patients. Two of four patients with DRPLA showed wavelength-dependent PPRs, and two other DRPLA patients showed quantity-of-light-dependent PPRs. Quantity-of-light-dependent PPRs are elicited by IPS containing more than a certain quantity of light, independent of the wavelength composition of the flashing light. Two of five subjects without epilepsy showed wavelength-dependent PPRs.

CONCLUSIONS

There are wavelength-dependent and quantity-of-light-dependent pathophysiologic mechanisms for eliciting PPRs by low-luminance IPS. Consideration of the quantity and wavelength composition of light from electronic screens will lead to the prevention of photosensitive seizures induced by electronic screen games.

Antiepileptic effects of topiramate on amygdaloid kindling in rats

We examined the antiepileptic properties of topiramate (TPM) in amygdaloid (AM) kindling in rats. Electrodes were implanted into the left AM of adult male Wistar rats. The animals were kindled at the after-discharge (AD) threshold. After the completion of kindling, the generalized seizure triggering threshold was determined. The drugs were administered intraperitoneally in animals which showed stable generalized convulsions at near-threshold stimulation. Intraperitoneal administration of TPM at doses of 25 mg/kg or more produced an anticonvulsive effect, but did not readily suppress limbic seizures. Complete suppression of AD was observed in only 3/8 rats at the highest dose of 200 mg/kg, which was not statistically significant. On the other hand, TPM at 100 and 200 mg/kg significantly delayed AM kindling. Thus, TPM showed modest therapeutic properties of conventional antiepileptic drugs in kindling model, those of TPM more closely resemble those of phenobarbital and the benzodiazepines than those of phenytoin and carbamazepine.

Epilepsia partialis continua of childhood involving bilateral brain hemispheres

OBJECTIVES

Epilepsia partialis continua (Kojewnikow's syndrome) can be classified into 2 groups. The 1st group had stable neurological deficit, and the 2nd group had slowly progressive neurological deficit. The latter usually manifests not tetraplegia, but hemiplegia. We describe 3 patients with epilepsia partialis continua, rapid neurological and mental deterioration, resulting in tetraplegia and serious mental deficits within 2 to 3 years from the onset.

RESULTS

Their interictal EEGs showed progressive findings of deterioration, which resulted in an inactive pattern or a pattern reminiscent of suppression-burst within several years. Their cranial CTs revealed rapid progressive atrophy of both hemispheres. Various screening tests failed to confirm a metabolic disease, a degenerative disease, or an infectious disease in the central nervous system.

CONCLUSION

Frequent status epilepticus might contribute to the bilateral brain involvement and the serious neurological and mental outcomes in young patients with epileptia partialis continua.

Effect of callosal bisection on seizure development and interhemispheric transfer effects in feline motor cortical kindling

Motor cortical (MC) kindling was carried out in 12 adult cats, seven with the corpus callosum (CC) intact and five with the CC bisected, to study interhemispheric transfer effects and the effect of callosal bisection on both seizure development and interhemispheric transfer effects. MC kindling developed from partial motor seizures to partial onset generalized convulsions. Interhemispheric negative transfer effect, but not positive, existed in secondary site kindling and primary site retest of the CC-intact group, as shown by: (i) electroencephalographically lateralized seizure development in the stimulated hemisphere; (ii) delayed generalization of partial onset generalized convulsions; and (iii) a markedly unstable generalized convulsive seizure state. The CC-bisected group showed: (i) significantly delayed seizure development from partial motor seizure stage to generalized convulsive seizure stage in primary and secondary kindling; (ii) facilitated intrahemispheric seizure development; (iii) the diminution of interhemispheric negative transfer effect; (iv) modified generalized convulsions showing extremely asymmetrical generalized convulsions shifting from contralaterally dominant convulsions to ipsilaterally dominant ones (n = 2) or alternate generalized convulsions changing from contralateral hemiconvulsions to ipsilateral ones (n = 3). The results obtained suggest that the CC plays a major role in interhemispheric seizure propagation as well as interhemispheric negative transfer effects in MC kindling and may have suppressive effect on intrahemispheric motor seizure development in MC kindling. However, interhemispheric seizure propagation and interhemispheric negative transfer effects were mediated via other structures, possibly subcortical structures, when the CC was bisected.

Effect of motor cortical kindling on subsequent ventral hippocampal kindling and the role of the corpus callosum in the cat

The effect of bilateral motor cortical (MC) kindling on subsequent unilateral ventral hippocampal (VHIPP) kindling was studied in four cats with the corpus callosum (CC) intact and five cats with the CC bisected, compared with nine cats with unilateral VHIPP kindling. Subsequent VHIPP kindling in CC-intact cats resulted in the modified development of limbic seizures to ipsilateral, not contralateral, focal motor seizures in one of four cats, significantly greater seizure regressions from generalized convulsive seizure stage to earlier seizure stages and delayed onset of focal motor seizures and generalized convulsions in partial onset generalized convulsions. CC bisection reduced the degree of seizure regression from generalized convulsive seizure stage to earlier stages, facilitated the development of the last limbic seizure to the first generalized convulsive seizure, accentuated hemiconvulsions and asymmetrical generalized convulsions and delayed the onset of generalized convulsions in partial onset generalized convulsions. The modified seizure development was also induced in three of five CC-bisected cats. Results indicate that bilateral MC kindling induces inhibitory effects on subsequent unilateral VHIPP kindling and the modified ictal progress from the VHIPP to the contralateral hemispheric motor structures and also that CC bisection interferes with the bilateralization and synchronization of convulsions, but reduces the inhibition of previously established MC kindling against VHIPP kindling and facilitates the development of focal motor seizures to secondarily generalized convulsions.

Two different pathological conditions of photoparoxysmal responses in hereditary dentatorubral-pallidoluysian atrophy

In order to reveal the pathophysiology of photoparoxysmal responses (PPRs) in photosensitive patients with hereditary dentatorubral-pallidoluysian atrophy (DRPLA) who had expansion of the CAG repeat in the DRPLA gene, we studied the characteristics of PPRs using optical filters with specific wavelength transmission. In two patients, the wavelength spectrum around 700 nm (670-720 nm) was apparently the only visible range essential for eliciting PPRs, and flash lights containing the essential wavelength elicited PPRs. In another patient, PPRs were elicited by flash lights above certain quantity of light and independent of the wavelength composition of the lights. These data suggest that two different pathological conditions contribute to PPRs in DRPLA patients; one condition depends on the essential wavelength spectrum around 700 nm, and the other not on the wavelength, but on the quantity of light. The condition contributing to PPRs in all three patients was not determined directly by the level of the CAG repeat expansion in the DRPLA gene.

Effects of single and repeated administration of sulthiame on amygdaloid kindled seizures in rats

In this study, we assessed the anti-convulsive effects of sulthiame (SUL) in amygdaloid (AM) kindled rats. Electrodes were implanted into the left AM of adult male Wistar rats. The animals were kindled at the after-discharge (AD) threshold. Upon completion of kindling, a generalized seizure triggering threshold was determined. The drugs were administered intraperitoneally in rats which reproducibly exhibited generalized convulsions at the near-threshold stimulation. Single administration of SUL (25-200 mg; n = 7-9) reduced the forelimb clonus (FCL) duration, but only the highest dose significantly regressed the secondarily generalized convulsion. During repeated administration of SUL, 50 mg/kg for 8 days, FCL duration was significantly alleviated until the fifth treatment day. With the dose of 200 mg/kg, significant suppression of secondary generalization was noted only until the second test day. On the other hand, significant reductions of FCL and AD duration were preserved afterwards. The anti-convulsive effects of SUL indicated in this study were not comparable to those of other standard anti-epileptic drugs reported from our laboratory.

Wavelength dependency of photoparoxysmal responses in photosensitive nonepileptic subjects

Using specially made optical filters, we analyzed the wavelength dependency of photoparoxysmal responses (PPRs) in five photosensitive nonepileptic subjects. The wavelength spectrum around 700 nm (680-700 nm) was estimated as the only visible spectrum essential for eliciting PPRs in two normal trichromat nonepileptic subjects, although the effect of some wavelength spectra (360-400 nm and 520-580 nm) was uncertain. The wavelength dependency of PPRs in two photosensitive nonepileptic subjects was the same as that found in some patients with photosensitive idiopathic generalized epilepsy.

Effects of clobazam and its active metabolite on GABA-activated currents in rat cerebral neurons in culture

PURPOSE

The antiepileptic effects of clobazam, a 1,5-benzodiazepine, have been well documented in animal experiments and clinical trials. However, the drug's mechanisms of antiepileptic actions are still undetermined. The purpose of this study was to learn how clobazam and its active metabolite modulate gamma-aminobutyric acid (GABA)-activated currents in rat cerebral neurons in culture.

METHODS

Whole-cell voltage-clamp recordings were performed on cultured cerebral neurons of the rat. Clobazam or its metabolite N-desmethylclobazam was dissolved in the extracellular solution and applied for 2 s by pressure ejection from a micropipette. To maintain GABA-activated currents, 2 mM Mg adenosine triphosphate (ATP) was added to the intracellular solution.

RESULTS

GABA elicited outward currents that were mediated by GABAA receptor-coupled Cl- channels. Applying clobazam with 10 microM GABA elicited enhanced outward currents. Flumazenil, an antagonist of the benzodiazepine receptor, inhibited the enhancing effect of clobazam. The enhancement ratio increased as much as 2.28-fold in a dose-dependent manner at a concentration of 3 microM clobazam. However, it started to decrease at a concentration of 10 microM clobazam. The metabolite N-desmethylclobazam was tested in the same manner, and exhibited an identical dose-dependent enhancement of GABA-activated currents.

CONCLUSIONS

The antiepileptic effects of the 1,5-benzodiazepines are attributed to the enhancement of GABAergic inhibitory neurotransmission. The antiepileptic effects of clobazam are thought to depend mainly on its active metabolite N-desmethylclobazam, which is present in high concentrations in patients who receive long-term clobazam. Clobazam's enhancement of GABA-activated currents was most marked on weaker GABA currents. We therefore infer that clobazam acts more efficiently on tissues in which the release of GABA is diminished.

Recommendation of early surgery from the viewpoint of daily quality of life

We surveyed pre- and postoperative levels of satisfaction with a range of the daily quality-of-life (QOL) domains in 132 sets of epilepsy surgery patients and their families. All patients underwent resective surgery for temporal lobe epilepsy and were monitored for > 2 years. Patient and family assessments showed patients' overall QOL markedly improves after surgery, depending on freedom from seizures. However, factors such as social contacts, family relations, or financial status improved little. Some families and patients were not satisfied with the postsurgical status, despite freedom from seizures. Patients who had surgery at a later age were not so satisfied with their postsurgical status as were patients who had surgery at a younger age, particularly on the QOL domains of role activities, memory function, leisure activities, or emotional well-being. This lower satisfaction level in older patients likely results from a variety of problems affecting patients during the long-lasting epileptic process; social handicaps, psychologic conflicts, and deterioration of cognitive/behavioral functions. Based on each case, we recommend that investigations start at an early stage of the illness, so that surgical intervention may be considered as early as possible.

Can absence status epilepticus be of frontal lobe origin?

Five women with an unclassifiable nonconvulsive status epilepticus (NCSE) characterized by young age at onset, prolonged confusions, focal motor seizures, and both generalized spike-and-wave discharges and focal epileptic discharges on the EEG were studied with video-EEG monitoring. Electrographically, the NCSE originated from the left frontal lobe in 4 patients, and the left hemisphere with multifocal seizure discharges in 1 patient. Focal motor seizures seemed to originate from the left hemisphere in all 5 patients, particularly from its anterior part in 3 of them. Results show that the NCSE is complex partial status epilepticus of frontal lobe origin electroclinically mimicking absence status epilepticus once it reaches a full-blown phase.

Wavelength specificity of photoparoxysmal responses in idiopathic generalized epilepsy

Using optic filters, we analyzed the wave-length specificity of photoparoxysmal responses (PPR) in photosensitive patients with idiopathic generalized epilepsy (IGE). We specified the wavelength spectrum approximately 700 nm (660-720 nm) as the only visible spectrum essential for eliciting PPR in some normal trichromat IGE patients and showed that any flashing lights containing this essential wavelength spectrum could elicit PPR independent of the number of stimulated cones. Absorption of the wavelength spectrum approximately 700 nm by optic filters eliminated PPR in normal trichromat IGE patients. In an IGE patient with deuteranomaly, intermittent flashing lights containing a part of the wavelength spectrum from 580 to 700 nm elicited PPR. These data suggest a new interpretation of wavelength specificity of PPR: Flashing lights containing the wavelength spectrum that does not produce antagonistic cone interactions at the level of retinal ganglion cells can elicit PPR in some photosensitive IGE patients.

Recombinant human erythropoietin stimulates tubular reabsorption of sodium in anesthetized rabbits

To determine whether recombinant human erythropoietin (rHuEPO) exerts a direct vasoconstrictive effect on renal arteries or affects renal function, we measured renal hemodynamics and renal function during a 30-min intrarenal infusion of rHuEPO in anesthetized rabbits without renal failure. Intrarenal infusion of rHuEPO at a rate of 100 U/min did not alter mean arterial pressure, renal blood flow, or renal vascular resistance, as compared with controls treated with vehicle. There were no significant rHuEPO-associated changes in glomerular filtration rate, filtration fraction, or arterial hematocrit. However, urine volume, urinary excretion of sodium and potassium, and fractional sodium excretion were significantly reduced by intrarenal infusion of rHuEPO. These observations indicate that rHuEPO has no direct effects on mean arterial pressure or renal hemodynamics, but that it stimulates net tubular sodium reabsorption, and reduces urine volume and urinary excretion of sodium and potassium in anesthetized rabbits without renal failure.