Noradrenaline enhances Na-K ATPase subunit expression by HuR-induced mRNA stabilization and their transportation to the cell surface through PLC and PKC mediated pathway: Implications with REMS-loss associated disorders

Rapid eye movement sleep (REMS) maintains brain excitability at least by regulating Na-K ATPase activity. Although REMS deprivation (REMSD)-associated elevated noradrenaline (NA) increases Na-K ATPase protein expression, its mRNA transcription did not increase. We hypothesized and confirmed both in vivo as well as in vitro that elevated mRNA stability explains the apparent puzzle. The mRNA stability was measured in control and REMSD rat brain with or without in vivo treatment with α1-adrenoceptor (AR) antagonist, prazosin (PRZ). Upon REMSD, Na-K ATPase α1-, and α2-mRNA stability increased significantly, which was prevented by PRZ. To decipher the molecular mechanism of action, we estimated NA-induced Na-K ATPase mRNA stability in Neuro-2a cells under controlled conditions and by transcription blockage using Actinomycin D (Act-D). NA increased Na-K ATPase mRNA stability, which was prevented by PRZ and propranolol (PRP, β-AR antagonist). The knockdown assay confirmed that the increased mRNA stabilization was induced by elevated cytoplasmic abundance of Human antigen R (HuR) and involving (Phospholipase C) PLC-mediated activation of Protein Kinase C (PKC). Additionally, using cell-impermeable Enz-link sulfo NHS-SS-Biotin, we observed that NA increased Na-K ATPase α1-subunits on the Neuro-2a cell surface. We conclude that REMSD-associated elevated NA, acting on α1- and β-AR, increases nucleocytoplasmic translocation of HuR and increases Na-K ATPase mRNA stability, resulting in increased Na-K ATPase protein expression. The latter then gets translocated to the neuronal membrane surface involving both PKC and (Protein Kinase A) PKA-mediated pathways. These findings may be exploited for the amelioration of REMSD-associated chronic disorders and symptoms.

Synthetic, biological and optoelectronic properties of phenoxazine and its derivatives: a state of the art review

Phenoxazines have sparked a lot of interest owing to their numerous applications in material science, organic light-emitting diodes, photoredox catalyst, dye-sensitized solar cells and chemotherapy. Among other things, they have antioxidant, antidiabetic, antimalarial, anti-alzheimer, antiviral, anti-inflammatory and antibiotic properties. Actinomycin D, which contains a phenoxazine moiety, functions both as an antibiotic and anticancer agent. Several research groups have worked on various structural modifications over the years in order to develop new phenoxazines with improved properties. Both phenothiazines and phenoxazines have gained prominence in medicine as pharmacological lead structures from their traditional uses as dyes and pigments. Organoelectronics and material sciences have recently found these compounds and their derivatives to be quite useful. Due to this, organic synthesis has been used in an unprecedented amount of exploratory alteration of the parent structures in an effort to create novel derivatives with enhanced biological and material capabilities. As a result, it is critical to conduct more frequent reviews of the work done in this area. Various stages of the synthetic transformation of phenoxazine scaffolds have been depicted in this article. This article aims to provide a state of the art review for the better understanding of the phenoxazine derivatives highlighting the progress and prospects of the same in medicinal and material applications.

circFNDC3B promotes esophageal squamous cell carcinoma progression by targeting MYO5A via miR-370-3p/miR-136-5p

BACKGROUND

Esophageal squamous cell carcinoma (ESCC) is a prevalent malignant tumor worldwide. Circular RNA (circRNA) is of great value in tumorigenesis progression. However, the mechanism of circFNDC3B in ESCC remains to be clarified.

METHODS

Firstly, the circular characteristics of circFNDC3B were evaluated by Actinomycin D and RNase R measurements. The functions of circFNDC3B in ESCC cells were examined by CCK-8, EdU and flow cytometry. Subsequently, the molecular mechanism of circFNDC3B was explained using luciferase reporter gene detection. Finally, we constructed xenograft model to prove the role of circFNDC3B in vivo.

RESULTS

Our study revealed that circFNDC3B was more stable than its linear RNA and prominently upregulated in ESCC. Functional findings suggested that silencing of circFNDC3B reduced the proliferation and enhanced apoptosis of ESCC cells in vitro. Meanwhile, knockdown of circFNDC3B attenuated tumor progression in vivo. Next, miR-370-3p/miR-136-5p was discovered to bind circFNDC3B. miR-370-3p/miR-136-5p reversed the promotive effect on cell proliferation and the inhibitory effect on cell apoptosis of circFNDC3B. MYO5A was a downstream target of miR-370-3p/miR-136-5p. CircFNDC3B served as a sponge for miR-370-3p/miR-136-5p and alleviated the prohibitory effect of miR-370-3p/miR-136-5p on MYO5A, which accelerated ESCC progression.

CONCLUSION

circFNDC3B positively adjusted the MYO5A expression via spongy miR-370-3p/miR-136-5p, hence achieving the cancer-promoting effect on ESCC. circFNDC3B was a prospective diagnosis marker for ESCC.

Comparing biweekly single-dose actinomycin D with multiday methotrexate therapy for low-risk gestational trophoblastic neoplasia (FIGO Score 0-4): study protocol for a prospective, multicentre, randomized trial

BACKGROUND

Single-agent chemotherapy using methotrexate or actinomycin D is the first-line treatment for patients with low-risk gestational trophoblastic neoplasia. Various methotrexate-based and actinomycin D-based single-agent regimens can be used. However, there is insufficient evidence to determine the superior regimen. To guide doctors in selecting a single-agent chemotherapy regimen for patients with low-risk gestational trophoblastic neoplasia, we will compare two regimens.

METHODS

We will conduct a multicentre, randomized, prospective clinical trial. Selected low-risk gestational trophoblastic neoplasia patients (FIGO score 0-4) will be randomized 1:1 to a biweekly single-dose actinomycin D group or a multiday methotrexate therapy group. The actinomycin D group will receive IV pulse actinomycin D (1.25 mg/m2) every 14 days, and the methotrexate group will receive methotrexate (50 mg) intramuscularly on days 1, 3, 5, and 7 (4 doses per cycle) and leucovorin (15 mg) intramuscularly on days 2, 4, 6, and 8. This process will be repeated every 14 days. The primary endpoints will include the complete remission rate by single-agent therapy and the overall complete remission rate. The secondary endpoints will include the duration needed to achieve complete remission after single-agent chemotherapy, number of courses needed to achieve complete remission after single-agent chemotherapy, incidence and severity of adverse effects, effects on menstrual conditions and ovarian function based on the anti-Mullerian hormone level, and patient-reported quality of life.

DISCUSSION

Previous clinical trials comparing biweekly single-dose actinomycin D with multiday methotrexate therapy for treating low-risk gestational trophoblastic neoplasia patients failed to meet the expected case number. Through this multicentre study, the complete remission ratio and efficacy difference between biweekly single-dose actinomycin D and multiday methotrexate therapy will be obtained. This study will also provide the basis for formulating a preferred regimen for treating patients with low-risk gestational trophoblastic neoplasia.

TRIAL REGISTRATION

ClinicalTrials.gov: NCT04562558, Registered on 13 September 2020 (Protocol version 2020-9-24, version 1.0).

AFM imaging of the transcriptionally active chromatin in mammalian cells' nuclei

BACKGROUND

Nuclear rigidity is traditionally associated with lamina and densely packed heterochromatin. Actively transcribed DNA is thought to be less densely packed. Currently, approaches for direct measurements of the transcriptionally active chromatin rigidity are quite limited.

METHODS

Isolated nuclei were subjected to mechanical stress at 60 g and analyzed by Atomic Force Microscopy (AFM).

RESULTS

Nuclei of the normal fibroblast cells were completely flattened under mechanical stress, whereas nuclei of the cancerous HeLa were extremely resistant. In the deformed HeLa nuclei, AFM revealed a highly-branched landscape assembled of ~400 nm closed-packed globules and their structure was changing in response to external influence. Normal and cancerous cells' isolated nuclei were strikingly different by DNA resistance to applied mechanical stress. Paradoxically, more transcriptionally active and less optically dense chromatin of the nuclei of the cancerous cells demonstrated higher physical rigidity. A high concentration of the transcription inhibitor actinomycin D led to complete flattening of HeLa nuclei, that might be related to the relaxation of supercoiled DNA tending to deformation. At a low concentration of actinomycin D, we observed the intermediary formation of stochastically distributed nanoloops and nanofilaments with different shapes but constant width ~ 180 nm. We related this phenomenon with partial DNA relaxation, while non-relaxed DNA still remained rigid.

CONCLUSIONS

The resistance to deformation of nuclear chromatin correlates with fundamental biological processes in the cell nucleus, such as transcription, as assessed by AFM.

GENERAL SIGNIFICANCE

A new outlook to studying internal nuclei structure is proposed.

Actinomycin D: a novel Pseudomonas aeruginosa quorum sensing inhibitor from the endophyte Streptomyces cyaneochromogenes RC1

The infections caused by Pseudomonas aeruginosa are difficult to treat due to its multidrug resistance. A promising strategy for controlling P. aeruginosa infection is targeting the quorum sensing (QS) system. Actinomycin D isolated from the metabolite of endophyte Streptomyces cyaneochromogenes RC1 exhibited good anti-QS activity against P. aeruginosa PAO1. Actinomycin D (50, 100, and 200 μg/mL) significantly inhibited the motility as well as reduced the production of multiple virulence factors including pyocyanin, protease, rhamnolipid, and siderophores. The images of confocal laser scanning microscopy and scanning electron microscopy revealed that the treatment of actinomycin D resulted in a looser and flatter biofilm structure. Real-time quantitative PCR analysis showed that the expression of QS-related genes lasI, rhlI, rhlR, pqsR, pslA, and pilA were downregulated dramatically. The production of QS signaling molecules N-(3-oxododecanoyl)-L-homoserine lactone and N-butanoyl-L-homoserine lactone were also decreased by actinomycin D. These findings suggest that actinomycin D, a potent in vitro anti-virulence agent, is a promising candidate to treat P. aeruginosa infection by interfering with the QS systems.

Nucleolar localization of the ErbB3 receptor as a new target in glioblastoma

Background

The nucleolus is a subnuclear, non-membrane bound domain that is the hub of ribosome biogenesis and a critical regulator of cell homeostasis. Rapid growth and division of cells in tumors are correlated with intensive nucleolar metabolism as a response to oncogenic factors overexpression. Several members of the Epidermal Growth Factor Receptor (EGFR) family, have been identified in the nucleus and nucleolus of many cancer cells, but their function in these compartments remains unexplored.

Results

We focused our research on the nucleolar function that a specific member of EGFR family, the ErbB3 receptor, plays in glioblastoma, a tumor without effective therapies. Here, Neuregulin 1 mediated proliferative stimuli, promotes ErbB3 relocalization from the nucleolus to the cytoplasm and increases pre-rRNA synthesis. Instead ErbB3 silencing or nucleolar stress reduce cell proliferation and affect cell cycle progression.

Conclusions

These data point to the existence of an ErbB3-mediated non canonical pathway that glioblastoma cells use to control ribosomes synthesis and cell proliferation. These results highlight the potential role for the nucleolar ErbB3 receptor, as a new target in glioblastoma.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12860-022-00411-y.

Inhibition of ribosome biogenesis by actinomycin D affects Arabidopsis root development

Actinomycin D has been reported to selectively inhibit rRNA synthesis and ribosome biogenesis, induce G2 checkpoint of cell cycle arrest in HeLa cells. In Arabidopsis, actinomycin D was also used as agent to preferentially inhibit the ribosome biosynthesis and ribosomal function. However, the function of actinomycin D on Arabidopsis root development remains to be elucidated. In this study, we exposed Arabidopsis seedlings to actinomycin D with the aim of evaluating the effects of ribosome biogenesis on root development. The results demonstrated that actinomycin D inhibited Arabidopsis root growth by reduced meristematic activity in a dose dependent manner. Exposure to actinomycin D decreased the expression of WOX5 and key stem cell niche-defining transcription factors SHR and PLT1, thus the loss function of QC identity and stem cell niche maintenance. In addition, dead cells were observed after actinomycin D treatment in root stele initials and DNA damage response was constitutively activated. Collectively, we propose that ribosome biogenesis plays key role in primary root growth through maintenance of root stem cell niche and DNA damage response in Arabidopsis.

Results with Floxuridine, Actinomycin D, Etoposide, and Vincristine in Gestational Trophoblastic Neoplasias with International Federation of Gynecology and Obstetrics Scores ≥5

BACKGROUND

5-fluorouracil-based multiagent chemotherapy has been used as the primary treatment for high-risk gestational trophoblastic neoplasia (GTN) in China for a few decades. This study aims to assess the efficacy and toxicity of floxuridine, actinomycin D, etoposide, and vincristine (FAEV) as a primary treatment for patients with GTN who had International Federation of Gynecology and Obstetrics (FIGO) scores ≥5.

MATERIALS AND METHODS

A total of 207 patients with GTN who had FIGO scores ≥5 were treated with FAEV as first-line chemotherapy at Peking Union Medical College Hospital between January 2002 and December 2017. Complete remission (CR), resistance, survival, toxicity, and reproductive outcomes were analyzed.

RESULTS

Of the 207 patients treated with FAEV, 9 (4.3%) required a change of chemotherapy owing to toxicity and 1 (0.5%) died of cerebral hernia 5 weeks after commencing treatment. The remaining 197 patients were assessable to determine the response to FAEV; among them, 168 (85.3%) achieved CR with FAEV and 29 (14.7%) developed resistance to FAEV. The 5-year overall survival rate of the entire cohort was 97.4%. Grade 3-4 neutropenia, thrombocytopenia, and anemia occurred in 28.4%, 6.8%, and 6.2% of cycles, respectively. No acute toxicity-related deaths occurred. Five patients developed acute myeloid leukemia 10-50 months after exposure to chemotherapy; another patient developed duodenal cancer 2 years after completing therapy. Sixty-one patients who preserved fertility wanted to become pregnant; 56 of them conceived.

CONCLUSION

The FAEV regimen is an effective primary treatment for patients with GTN who have FIGO scores ≥5 and has predictable and manageable toxicity.

IMPLICATIONS FOR PRACTICE

The most commonly used multiagent chemotherapy for high-risk gestational trophoblastic neoplasia (GTN) is etoposide, methotrexate and actinomycin D/cyclophosphamide and vincristine (EMA/CO) worldwide. However, 5-fluorouracil-based multiagent chemotherapy has been used as a primary treatment for high-risk GTN in China for a few decades. This study evaluated the efficacy and toxicity of floxuridine, actinomycin D, etoposide, and vincristine (FAEV) as a primary treatment for patients with GTN who have International Federation of Gynecology and Obstetrics (FIGO) scores ≥5. The study's data demonstrated that FAEV as a primary treatment achieved favorable outcomes for patients with FIGO scores ≥5. Toxicities that result from the FAEV regimen are predictable and manageable. The FAEV regimen may provide another option for the treatment of GTN.

Protein synthesis and actin polymerization in the rapid effects of 17β-estradiol on short-term social memory and dendritic spine dynamics in female mice

Estrogens rapidly facilitate learning and memory, including social recognition - the ability of an animal to recognize another. In ovariectomized female mice, systemic or dorsal hippocampal administration of 17β-estradiol (E2) facilitates short-term social recognition memory within 40 min. Within the same timeframe, E2 increases dendritic spine density in CA1 dorsal hippocampal neurons of behavioural task-naïve mice and in hippocampal sections. Mechanisms underlying these effects remain unclear. Estrogens rapidly modulate actin cytoskeletal dynamics through actin polymerization and the translation of key synaptic proteins. We first determined doses of actin polymerization inhibitor latrunculin A (LAT) and protein synthesis inhibitor anisomycin (ANI) that would block short-term social recognition memory when infused into the dorsal hippocampus of ovariectomized female mice 15 min prior to testing. The highest doses that did not block social recognition prevented the facilitating effects of E2, whereas DNA transcription inhibitor, actinomycin D, could not block social recognition. As task performance may interfere with E2-facilitated increases in dendritic spine density, dendritic spine density and length were examined in task-performing and task-naïve mice. E2 increased dendritic spine density 15 but not 40 min following treatment, regardless of whether the animal had performed the social recognition task. This effect was blocked by LAT, but not ANI. Thus, both actin polymerization and protein synthesis are necessary for E2 to rapidly facilitate social recognition, whereas actin polymerization, but not protein synthesis, is required for the rapid increase in dendritic spine density brought on by E2.

Efficient, green, and rapid strategy for separating actinomycin D and X2 using supercritical fluid chromatography

Actinomycin D has long been used as a first-line antitumor drug in clinical practice. Actinomycin X₂, a new drug lead, is often isolated along with actinomycin D. The minor differences between the two actinomycin analogs pose a daunting challenge in separation. In this study, supercritical fluid chromatography (SFC) was successfully utilized for the purification of actinomycin X₂ and actinomycin D from a marine derived Streptomyces sp. DQS-5. After one-step SFC purification, the purities of these two compounds were determined to be 97.3 % and 97.8 %, respectively. This method provides a green alternative for the separation of these pharmacologically important actinomycin antibiotics. This study also demonstrated the development of a simple and rapid method for the separation of natural products based on SFC.

Multidisciplinary treatment of life-threatening hemoptysis and paraplegia of choriocarcinoma with pulmonary, hepatic and spinal metastases: A case report

BACKGROUND

Although choriocarcinoma is thought to be a malignancy curable by chemotherapy, there remain difficult and challenging problems in cases with high prognostic scores or extensive metastases, for which the treatment is limited. Particularly, chemotherapy in combination with other treatments offers promising therapeutic potential for these cases.

CASE SUMMARY

We present the case of a 40-year-old female patient who suffered from life-threatening hemoptysis and paraplegia due to choriocarcinoma with pulmonary, hepatic and spinal metastases. The patient successfully recovered after multidisciplinary treatment consisting of 21 cycles of intravenous chemotherapy, radiofrequency ablation of multiple hepatic metastases, intensity-modulated radiation therapy for spinal metastases and routine physiotherapy. To our knowledge, it is the first reported case of recovery from pulmonary, hepatic and spinal metastases of choriocarcinoma with no specific primary site. Moreover, this is the first reported clinical attempt on 5-d actinomycin D as primary chemotherapy in ultrahigh-risk gestational trophoblastic neoplasia.

CONCLUSION

The case supports the opinion that the individualized treatment of choriocarcinoma by a multidisciplinary approach can accomplish optimal therapeutic effects.

Effectiveness and toxicity of second-line actinomycin D in patients with methotrexate-resistant postmolar low-risk gestational trophoblastic neoplasia

OBJECTIVES

The purpose of this study was to evaluate both the outcomes and toxicity of second-line actinomycin D (ActD) chemotherapy in methotrexate (MTX) - resistant low-risk postmolar gestational trophoblastic neoplasia (GTN) with 5-day ActD versus pulsed ActD.

METHODS

This retrospective cohort study included patients with MTX-resistant low-risk postmolar GTN from 1974 to 2016. Second-line chemotherapy consisted of 5-day ActD (10-12 μg/kg per day for 5 days every 14 days) or biweekly ActD (1.25 mg/m² every 2 weeks). Data on patient characteristics, disease presentation, treatment outcome, and toxicity were collected.

RESULTS

Sixty-eight MTX-resistant patients receiving ActD as second-line chemotherapy were identified (5-day ActD, 53 patients; pulsed ActD, 15 patients). No significant differences were observed in patient/disease characteristics and sustained remission (overall rate 72%) between second-line ActD regimens. Time to hCG remission was significantly faster (median 21 vs 47 days, p = .04) and required fewer treatment cycles (median 1 vs 2, p < .001) with 5-day ActD. Thrombocytopenia was only observed with 5-day ActD (64.6 vs 0%, p < .001). The frequency (60.4 vs 16.7%, p = .009) and severity (grade 3: 37.9 vs 0%, p = .045) of oral mucositis was significantly higher with 5-day ActD. Grade 2 alopecia was significantly more frequent (70.6 vs 16.7%, p = .02) with 5-day ActD.

CONCLUSIONS

While 5-day ActD and pulsed ActD achieve comparable remission rates, due to its reduced toxicity, ease of administration, and patient convenience, pulsed ActD should be the treatment of choice for MTX-resistant postmolar low-risk GTN.

The 16-year experience in treating low-risk gestational trophoblastic neoplasia patients with failed primary methotrexate chemotherapy

Objective

To assess the outcomes and toxic effects of 5-day actinomycin D (Act-D) salvage therapy and to explore the predictors of Act-D resistance in patients with low-risk gestational trophoblastic neoplasia (GTN)who failed 5-day methotrexate (MTX) chemotherapy.

Methods

This retrospective study analyzed patients with low-risk GTN administered Act-D salvage therapy after failing MTX chemotherapy at Women's Hospital, School of Medicine Zhejiang University between January 2000 and December 2015. The clinical parameters of these patients were collected and analyzed.

Results

The final analysis included 89 cases. Of these, 73 cases (82.02%) responded to salvage Act-D. The remaining 16 resistant cases were switched to etoposide, MTX, Act-D/cyclophosphamide, and vincristine chemotherapy and achieved complete remission. Serum human chorionic gonadotrophin levels before Act-D salvage therapy (hCG_Act-D)in the Act-D-resistant cases were significantly higher than those in the Act-D responders (median 605 vs. 103 IU/L, p=0.009). However, the range of hCG_Act-D values in Act-D responders was wider than that in Act-D-resistant cases (5.76–16,664 IU/L vs. 11.43–6,732 IU/L). Thus, assigning a general cut-off value was difficult considering the individual setting. Except for 2 cases requiring other salvage regimens due to Act-D toxicity, 97.80% of cases (89/91) tolerated the toxicity. During at least 1-year follow-up, the survival rate was 100.00% and no case developed recurrence.

Conclusion

Based on the good therapeutic effect and tolerable toxicity, we recommend Act-D salvage therapy for all patients with low-risk GTN who fail primary MTX chemotherapy. The higher serum hCG levels before Act-D salvage therapy may be associated with resistance to this treatment.

The efficacy and toxicity of 4-day chemotherapy with methotrexate, etoposide and actinomycin D in patients with choriocarcinoma and high-risk gestational trophoblastic neoplasia

OBJECTIVE

This study aimed to evaluate the efficacy and toxicity of 4-day chemotherapy with methotrexate, etoposide, and actinomycin D (MEA) for patients who were diagnosed with choriocarcinoma and high-risk gestational trophoblastic neoplasia (GTN).

METHODS

Between January 1999 and December 2015, 29 patients were treated with 4-day MEA after being diagnosed with choriocarcinoma or high-risk GTN. Complete remission to 4-day MEA and adverse effects were retrospectively evaluated.

RESULTS

The complete remission rates were 79.3% (23/29) and 87.5% (21/24) in all patients and in those who received 4-day MEA as first-line therapy, respectively. Of six patients who developed drug resistance to 4-day MEA, three patients showed complete remission by other treatments, while the other three patients died of the disease. The major adverse effects were leukocytopenia, anemia, and nausea. Of 23 patients who were cured with 4-day MEA, treatment was changed to the etoposide and actinomycin D (EA) regimen in 14 patients, because of leukocytopenia, hepatotoxicity, and stomatitis. Among 20 patients who required hormonal therapy, 15 patients showed normal menstrual cycles after therapy. Five patients had nine conceptions (seven term live births and two spontaneous abortions). No babies were premature or had low birth weight nor did they have congenital anomalies.

CONCLUSION

The results suggest that the efficacy and the adverse effects of 4-day MEA for choriocarcinoma and high-risk GTN may be the same level as EMA/CO. However, further study will be needed for determining the criteria of changing the treatment regimen from 4-day MEA to the EA regimen.

Anti-Mesothelin Recombinant Immunotoxin Therapy for Colorectal Cancer

BACKGROUND

Mesothelin (MSLN) is a cell surface glycoprotein expressed at a high level on many malignancies, including pancreatic adenocarcinoma, serous ovarian cancer, and epithelioid mesothelioma. MSLN-targeted recombinant immunotoxins (RITs) consist of an anti-MSLN Fv fused to the catalytic domain of Pseudomonas exotoxin A. Recent data has also shown that MSLN is expressed at clinically relevant levels on the surface of colorectal cancer (CRC). In this study, CRC cell lines were tested for MSLN expression and susceptibility to MSLN-targeted RITs.

MATERIALS AND METHODS

CRC cell lines were tested for membranous MSLN expression via flow cytometry. Cell lines expressing MSLN were tested by WST-8 cell viability assay for sensitivity to various RITs and chemotherapeutic agents. CRC cell line SW-48 was tested in a mouse model for response to RIT as a single agent or in combination with actinomycin D and oxaliplatin.

RESULTS

CRC cell lines were susceptible to anti-MSLN RITs at half maximal inhibitory concentration levels comparable with those previously described in pancreatic cancer cell lines. In a nude mouse model, MSLN-targeted RIT treatment of SW48 CRC tumors resulted in a significant decrease in tumor volume. Although combination therapy with standard of care chemotherapeutic oxaliplatin did not improve tumor regressions, combination therapy with actinomycin D resulted in > 90% tumor volume reduction with 50% complete regressions.

CONCLUSIONS

These data support the development of anti-MSLN RITs as well as other MSLN-targeted therapies for CRC.

Low-risk gestational trophoblastic neoplasia: A single-center experience from Saudi Arabia

Objective

To report our single-center experience in terms of patient clinical characteristics, treatment outcomes, and chemotherapy-related toxicities in patients with low-risk gestational trophoblastic neoplasia (GTN).

Materials and Methods

A retrospective cross-sectional study (2008-2013) was conducted at a tertiary health-care hospital in Saudi Arabia. Forty-four (n = 44) patients met the inclusion criteria for low-risk GTN. Methotrexate (MTX) was administered in a 5-day regimen: 0.3-0.5mg/kg intravenously (IV) daily for 5 days every 2 weeks (maximum 25mg per dose). Actinomycin D (ActD) was administered 1.25mg/m² pulsed IV every 2 weeks.

Results

The majority of patients had molar pregnancy as the antecedent event (86%), developed GTN within the first 4 months after the initial evacuation (93.2%), had human chorionic gonadotropin levels between 1,000 and 10,000 mIU/dL (36.3%), and had the World Health Organization prognostic scores from 0 to 2 (48.7%). Only 38 patients accepted treatment with chemotherapy. A total of 37 patients received first-line MTX; 34 patients of them achieved complete remission (CR, 92%). The three patients who developed MTX resistance were salvaged with sequential ActD and all achieved CR of 100%. Only one patient received first-line ActD and achieved CR. The overall survival as well as cure rate for all patients with low-risk GTN was 100%. No patient developed MTX-related hepatic toxicity or ActD-related blister formation. No severe adverse effects occurred.

Conclusion

Our 5-day IV MTX regimen was highly effective in treating patients with low-risk GTN, with CR rate of 92% and no severe toxicity. Primary and sequential ActD therapy appears to be very effective.

Efficacy of Combination Therapy with Actinomycin D and Methotrexate in the Treatment of Low-Risk Gestational Trophoblastic Neoplasia

OBJECTIVES

We aimed to identify an optimal regimen for low-risk gestational trophoblastic neoplasia (LR-GTN) providing reduction in dosage and toxicity/side effects, enhancement of therapeutic efficacy, and a shorter treatment duration.

METHODS

A total of 149 LR-GTN patients were enrolled in the affiliated Beijing Maternity Hospital of Capital Medical University from January 2014 to January 2017 and randomly divided into 3 groups with 50 cases in the methotrexate (MTX) group, 49 in actinomycin D (ACT-D) group, and 50 in ACT-D+MTX group. Follow-up recorded symptoms, physical and bimanual gynecological examinations, routine blood test, serum β-HCG level, liver and renal functions, electrolytes, electrocardiogram before each treatment course, and pelvic and abdominal B-mode ultrasound or pelvic/abdominal/chest computed tomography.

RESULTS

Serum complete remission (SCR) was 96.0, 87.8, and 83.7% for the ACT-D+MTX, ACT-D, and MTX groups, respectively, with SCR being highest in the ACT-D+MTX group, statistically higher than in the MTX group. Vomiting was the only side effect differing significantly by chemotherapy regimen, with a distinctly higher incidence in the ACT-D+MTX group compared with the MTX group (p = 0.028). The reduction rate of serum β-HCG in the ACT-D+MTX group was significantly greater than in the other 2 groups.

CONCLUSION

Combined ACT-D+MTX chemotherapy achieved overall better efficacy and showed less toxicity than ACT-D or MTX alone, and thus can be prioritized for the treatment of LR-GTN.

Modeling improved production of the chemotherapeutic polypeptide actinomycin D by a novel Streptomyces sp. strain from a Saharan soil

The novel bioactive actinobacterial strain GSBNT10 obtained from a Saharan soil, was taxonomically characterized using a polyphasic approach. 16S rRNA gene sequence analysis supported the classification of the isolate within the genus Streptomyces indicating it as a novel species. The major metabolite responsible of the bioactivity was purified and structurally characterized as actinomycin D (act-D) by mass spectrometric and nuclear magnetic resonance analyses Plackett-Burman design (PBD) and response surface methodology (RSM) were applied in order to optimize the medium formulation for the production of this bioactive metabolite. By PBD experiments, NaNO₃, K₂HPO₄ and initial pH value were selected as significant variables affecting the metabolite production. Central Composite Design (CCD) showed that adjustment of the fermentative medium at pH 8.25, K₂HPO₄ at 0.2 gL^-1 and NaNO₃ at 3.76 gL^-1 were the values suiting the production of act-D. Moreover, the results obtained by the statistical approach were confirmed by act-D detection using the HPLC equipped with a diode array detector and coupled online with electrospray-mass spectrometry (ESIMS) technique. act-D production was highly stimulated, obtaining a good yield (656.46 mgL^-1) which corresponds to a 58.56% increase compared with the non-optimized conditions and data from LC-ESIMS technique efficiently confirmed the forecast from RSM.

Hepatocellular Carcinoma and Nuclear Paraspeckles: Induction in Chemoresistance and Prediction for Poor Survival

BACKGROUND/AIMS

Hepatocellular carcinoma (HCC) represents the second most common cause of cancer-related deaths worldwide, not least due to its high chemoresistance. The long non-coding RNA nuclear paraspeckle assembly transcript 1 (NEAT1), localised in nuclear paraspeckles, has been shown to enhance chemoresistance in several cancer types. Since data on NEAT1 in HCC chemosensitivity are completely lacking and chemoresistance is linked to poor prognosis, we aimed to study NEAT1 expression in HCC chemoresistance and its link to HCC prognosis.

METHODS

NEAT1 expression was determined in either sensitive, or sorafenib, or doxorubicin resistant HepG2, PLC/PRF/5, and Huh7 cells by qPCR. Paraspeckles were detected by immunostaining of paraspeckle component 1 (PSPC1) in cell culture and in a cohort of HCC patients. PSPC1 expression was correlated with clinical data. The expression of transcript variants of NEAT1 and transcripts encoding the paraspeckle-associated proteins was analysed in the TCGA liver cancer data set.

RESULTS

NEAT1 was overexpressed in all three sorafenib and doxorubicin resistant cell lines. Paraspeckles were present in all chemoresistant cells, whereas no signal was detected in the sensitive cells. Expression of NEAT1 transcripts as well as transcripts encoding PSPC1, NONO, and RBM14 was increased in tumour tissue. Expression of PSPC1, NONO, and RBM14 transcripts was significantly associated with poor survival, whereas NEAT1 expression was not. Immunohistochemical analysis revealed that nuclear and cytoplasmic PSPC1-positivity was significantly associated with shorter overall survival of HCC patients.

CONCLUSION

Our data show an induction of NEAT1 in HCC chemoresistance and a high correlation of transcripts encoding paraspeckle-associated proteins with poor survival in HCC. Therefore, NEAT1, PSPC1, NONO, and RBM14 might be promising targets for novel HCC therapies, and the paraspeckle-associated proteins might be clinical markers and predictors for poor survival in HCC.

Soft Tissue Cancer Management: Isolated Limb Infusion for Sarcoma

Background

Sarcoma is a heterogeneous group of malignancies comprising almost 80 subtypes of bone and soft tissue cancers. Previously, all subtypes were managed identically. Advancements in biological and genetic studies have revealed that sarcoma subtypes display varying characteristics and therefore require tailored treatments. Locally advanced soft tissue malignancies of both the trunk and the extremities can present significant challenges for treatment. At present, a negative surgical resection margin is the only definitive treatment despite attempts to use neoadjuvant and adjuvant therapies. In patients with locally advanced non-resectable soft tissue sarcoma (STS), the current practice would advocate amputation. However, studies suggest that limb salvage may be possible with radiotherapy or regional chemotherapy using isolated limb perfusion or isolated limb infusion (ILI). An ideal treatment modality for non-resectable STS would strive for preservation of anatomy and functionality as well as improve quality of life. The aim of the study was to investigate the efficacy of isolated limb infusion as an alternative treatment modality for non-resectable locally advanced STS.

Methods

The efficacy of ILI was retrospectively investigated in 10 patients with STS. All patients received ILI with melphalan and actinomycin at the North Estonia Medical Centre Foundation, Tallinn, Estonia from September 1, 2014 to May 31, 2018. The procedures were performed in a lower extremity in 8 patients and in an upper extremity in 2 patients. The 6-month overall response rate was 78% and the overall limb salvage rate was 100%. The distant metastatis-free survival was longer for responders than for non-responders.

Results and Conclusions

ILI is an alternative treatment modality for regional disease control and limb preservation in patients with cutaneous and soft tissue malignant neoplasms of the extremities. The short-term response rates are encouraging and the median overall survival shows good results in this highly complex patient population.

Diversity and antagonistic potential of Actinobacteria from the fungus-growing termite Odontotermes formosanus

43 Actinobacteria were isolated from the nest of Odontotermes formosanus. A phylogenetic analysis of 23 Actinobacteria isolates with different morphotypes showed that they did not form a monophyletic group. Antifungal bioassays exhibited that many strains inhibit both the termite cultivar Termitomyces and the competitor Xylaria. However, Actinobacteria inhibited the competitor Xylaria more severely than the termite cultural fungus Termitomyces. Furthermore, two Actinobacteria (Streptomyces sp. T33 and S. bellus T37) had a selective antifungal effect on Xylaria, with the inhibition zone of 25.5 and 8.9 mm, respectively. An actinomycin D was isolated from the strain T33 and had potent antifungal activity against Xylaria with IC50 value of less than 3.1 µg/mL. In addition, further bioassays showed that actinomycin D possessed potent antifungal activities against Magnaporthe grisea (IC50 = 0.9 µg/mL), Fusarium oxysporum f. sp. cucumerinum (IC50 = 2.2 µg/mL), Valsa mali (IC50 = 1.7 µg/mL), Rhizoctonia solani (IC50 = 10.3 µg/mL), Dothiorella gregaria (IC50 = 12.5 µg/mL) and F. oxysporum f. sp. mornordicae (IC50 = 14.3 µg/mL), which were comparable to those of referenced cycloheximide. The findings of the present study suggest that the termite-associated Actinobacteria have a potential to be used as microbial fungicide.

mRNA Stability Assay Using transcription inhibition by Actinomycin D in Mouse Pluripotent Stem Cells

Gene expression is regulated through multiple steps at both transcriptional and post-transcriptional levels. The net abundance of mature mRNA species in cells is determined by the balance between transcription and degradation. Thus, the regulation of mRNA stability is a key post-transcriptional event that can greatly affect the net level of mRNAs in cells. The mRNA stability within cells can be measured indirectly by analyzing the mRNA half-life following transcription inhibition, where changes in mRNA levels are assumed to reflect mRNA degradation. Determination of mRNA half-life as a measure of mRNA stability is useful in understanding gene expression changes and underlying mechanisms regulating the level of transcripts at different physiological conditions or developmental stages. The protocol described here presents the analysis of mRNA decay as a measure for determining mRNA stability after transcriptional inhibition with Actinomycin D treatment in control and SRSF3 depleted mouse induced pluripotent stem cells (iPSC).

The role of solute carrier (SLC) transporters in actinomycin D pharmacokinetics in paediatric cancer patients

BACKGROUND

Actinomycin D is used for treatment of paediatric cancers; however, a large inter-patient pharmacokinetic (PK) variability and hepatotoxicity are significant limitations to its use and warrant further investigation. Elimination of actinomycin D may be mediated by transporters, as the drug does not seem to undergo significant metabolism. We investigated the role of solute carrier (SLC) transporters in actinomycin D PK.

METHODS

Fourteen key SLCs were screened through probe substrate uptake inhibition by actinomycin D in HEK293 cells. Uptake of actinomycin D was further studied in candidate SLCs by measuring intracellular actinomycin D using a validated LCMS assay. Pharmacogenetic analysis was conducted for 60 patients (Clinical trial: NCT00900354), who were genotyped for SNPs for OAT4 and PEPT2.

RESULTS

OAT4, OCT2, OCT3 and PEPT2 showed significantly lower probe substrate uptake (mean ± SD 75.0 ± 3.5% (p < 0.0001), 74.8 ± 11.2% (p = 0.001), 81.2 ± 14.0% (p = 0.0083) and 70.7 ± 5.7% (p = 0.0188)) compared to that of control. Intracellular accumulation of actinomycin D was greater compared to vector control in OAT4-transfected cells by 1.5- and 1.4-fold at 10 min (p = 0.01) and 20 min (p = 0.03), and in PEPT2-transfected cells by 1.5- and 1.7-fold at 10 min (p = 0.047) and 20 min (p = 0.043), respectively. Subsequent clinical study did not find a significant association between OAT4 rs11231809 and PEPT2 rs2257212 genotypes, and actinomycin D PK parameters such as clearance (CL) and volume of distribution (V_d).

CONCLUSION

Transport of actinomycin D was mediated by OAT4 and PEPT2 in vitro. There was a lack of clinical significance of OAT4 and PEPT2 genotypes as predictors of actinomycin D disposition in paediatric cancer patients.

The Alzheimer's disease-associated TREM2 gene is regulated by p53 tumor suppressor protein

TREM2 mutations evoke neurodegenerative disorders, and recently genetic variants of this gene were correlated to increased risk of Alzheimer's disease. The signaling cascade originating from the TREM2 membrane receptor includes its binding partner TYROBP, BLNK adapter protein, and SYK kinase, which can be activated by p53. Moreover, in silico identification of a putative p53 response element (RE) at the TREM2 promoter led us to hypothesize that TREM2 and other pathway elements may be regulated in p53-dependent manner. To stimulate p53 in synergistic fashion, we exposed A549 lung cancer cells to actinomycin D and nutlin-3a (A + N). In these cells, exposure to A + N triggered expression of TREM2, TYROBP, SYK and BLNK in p53-dependent manner. TREM2 was also activated by A + N in U-2 OS osteosarcoma and A375 melanoma cell lines. Interestingly, nutlin-3a, a specific activator of p53, acting alone stimulated TREM2 in U-2 OS cells. Using in vitro mutagenesis, chromatin immunoprecipitation, and luciferase reporter assays, we confirmed the presence of the p53 RE in TREM2 promoter. Furthermore, activation of TREM2 and TYROBP by p53 was strongly inhibited by CHIR-98014, a potent and specific inhibitor of glycogen synthase kinase-3 (GSK-3). We conclude that TREM2 is a direct p53-target gene, and that activation of TREM2 by A + N or nutlin-3a may be critically dependent on GSK-3 function.

Pulse actinomycin D as first-line treatment of low-risk post-molar non-choriocarcinoma gestational trophoblastic neoplasia

Background

Little data exists predicting the resistance to actinomycin D (Act-D) single-agent for gestational trophoblastic neoplasia (GTN). The objective was to determine the overall success of pulse Act-D and the factors predictive of resistance to pulse Act-D in the treatment of low-risk, non-choriocarcinoma post-molar GTN.

Methods

From January 2013 to October 2016, according to the FIGO criteria for the diagnosis of post-molar disease and the FIGO risk-factor scoring system for GTN, a total of 135 patients with post-molar non-choriocarcinoma GTN who were chemotherapy-naive with a FIGO score < 7 were treated with single-agent pulse Act-D as a first-line regimen, in Peking Union Medical College Hospital. The pulse Act-D regimen is defined as 1.25 mg/m² (max 2 mg) IV push every other week. All patients were followed until May 2017. Epidemiological and clinical data were compared between patients with remission and resistance to Act-D to determine predictive factors by univariate and multivariate analysis.

Results

Ninety-six of 135 patients (71.1%) achieved complete remission after first-line chemotherapy of pulse Act-D. In multivariate analysis, existing invasive uterine lesions observed by pre-chemotherapy transvaginal ultrasound (odds ratio [OR] 7.5, 95% confidence intervals [CI] 2.7–20.8), FIGO score ≥ 5 (OR 15.2, 95% CI 1.5–156.1) and pre-chemotherapy levels of β-hCG ≥ 4000 IU/L (OR 3.1, 95% CI 1.2–8.3) were independent high-risk factors predicting resistance to pulse Act-D as single-agent chemotherapy. During follow-up, no relapse, treatment-associated serious adverse events, or death occurred.

Conclusions

As first-line chemotherapy, pulse Act-D was effective and tolerable for patients with low-risk post-molar non-choriocarcinoma. Existing invasive uterine lesions observed by pre-chemotherapy transvaginal ultrasound, a FIGO score ≥ 5, and pre-chemotherapy levels of β-hCG ≥ 4000 IU/L were independent factors for resistance to pulse Act-D.

Electronic supplementary material

The online version of this article (10.1186/s12885-018-4512-5) contains supplementary material, which is available to authorized users.

Genome-wide identification and characterization of the RIO atypical kinase family in plants

Members of the right open reading frame (RIO) atypical kinase family are present in all three domains of life. In eukaryotes, three subfamilies have been identified: RIO1, RIO2, and RIO3. Studies have shown that the yeast and human RIO1 and RIO2 kinases are essential for the biogenesis of small ribosomal subunits. Thus far, RIO3 has been found only in multicellular eukaryotes. In this study, we systematically identified members of the RIO gene family in 37 species representing the major evolutionary lineages in Viridiplantae. A total of 84 RIO genes were identified; among them, 41 were classified as RIO1 and 43 as RIO2. However, no RIO3 gene was found in any of the species examined. Phylogenetic trees constructed for plant RIO1 and RIO2 proteins were generally congruent with the species phylogeny. Subcellular localization analyses showed that the plant RIO proteins were localized mainly in the nucleus and/or cytoplasm. Expression profile analysis of rice, maize, and Arabidopsis RIO genes in different tissues revealed similar expression patterns between RIO1 and RIO2 genes, and their expression levels were high in certain tissues. In addition, the expressions of plant RIO genes were regulated by two drugs: mycophenolic acid and actinomycin D. Function prediction using genome-wide coexpression analysis revealed that most plant RIO genes may be involved in ribosome biogenesis. Our results will be useful for the evolutionary analysis of the ancient RIO kinase family and provide a basis for further functional characterization of RIO genes in plants.

An in vitro study of the interaction of the chemotherapeutic drug Actinomycin D with lung cancer cell lines using Raman micro-spectroscopy

The applications of Raman microspectroscopy have been extended in recent years into the field of clinical medicine, and specifically in cancer research, as a non-invasive diagnostic method in vivo and ex vivo, and the field of pharmaceutical development as a label-free predictive technique for new drug mechanisms of action in vitro. To further illustrate its potential for such applications, it is important to establish its capability to fingerprint drug mechanisms of action and different cellular reactions. In this study, cytotoxicity assays were employed to establish the toxicity profiles for 48 and 72 hours exposure of lung cancer cell lines, A549 and Calu-1, after exposure to Actinomycin D (ACT) and Raman micro-spectroscopy was used to track its mechanism of action at subcellular level and subsequent cellular responses. Multivariate data analysis was used to elucidate the spectroscopic signatures associated with ACT chemical binding and cellular resistances. Results show that the ACT uptake and mechanism of action are similar in the 2 cell lines, while A549 cells exhibits spectral signatures of resistance to apoptosis related to its higher chemoresistance to the anticancer drug ACT. The observations are discussed in comparison to previous studies of the similar anthracyclic chemotherapeutic agent Doxorubicin. A, Preprocessed Raman spectrum of ACT stock solution dissolved in sterile water and mean spectrum with SD of (B) nucleolus, (C) nucleus and (D) cytoplasm of A549 cell lines after 48 hours exposure to the corresponding IC₅₀ .

Identification and characterization of Streptomyces flavogriseus NJ-4 as a novel producer of actinomycin D and holomycin

This paper is the first public report that Streptomyces flavogriseus can produce both actinomycin D and holomycin. The actinomycete strain NJ-4 isolated from the soil of Nanjing Agricultural University was identified as S. flavogriseus. This S. flavogriseus strain was found for the first time to produce two antimicrobial compounds that were identified as actinomycin D and holomycin. GS medium, CS medium and GSS medium were used for the production experiments. All three media supported the production of actinomycin D, while holomycin was detected only in GS medium and was undetectable by HPLC in the CS and GSS media. The antimicrobial activity against B. pumilus, S. aureus, Escherichia coli, F. moniliforme, F. graminearum and A. niger was tested using the agar well diffusion method. Actinomycin D exhibited strong antagonistic activities against all the indicator strains. Holomycin exhibited strong antagonistic activities against B. pumilus, S. aureus and E. coli and had antifungal activity against F. moniliforme and F. graminearum but had no antifungal activity against A. niger. The cell viability was determined using an MTT assay. Holomycin exhibited cytotoxic activity against A549 lung cancer cells, BGC823 gastric cancer cells and HepG2 hepatocellular carcinoma cells. The yield of actinomycin D from S. flavogriseus NJ-4 was 960 mg/l. S. flavogriseus NJ-4 exhibits a distinct capability and has the industrial potential to produce considerable yields of actinomycin D under unoptimized conditions.

Actinomycin D synergistically enhances the cytotoxicity of CDDP on KB cells by activating P53 via decreasing P53-MDM2 complex

The aim of this study is to investigate the synergism of low dose of actinomycin D (LDActD) to the cytotoxicity of cisplatin (CDDP) on KB cells. The role of P53 reactivation by LDActD in the synergism and its mechanism were further studied. Cell viability was determined by MTT assay. Apoptosis was determined by AnnexinV-FITC/PI staining. Mitochondrial membrane potential (MMP) was detected by JC-1 staining. Expression of proteins was detected by Western blotting (WB) and/or immunofluorescence (IF). Molecular docking of actinomycin D (ACTD) to Mouse double minute 2 homolog (MDM2) and Mouse double minute 2 homolog X (MDMX). MDMX was analyzed by Discovery Studio. The content of P53-MDM2 complex was detected by ELISA assay. The cytotoxicity of CDDP was increased by the combination of LDActD in kinds of cancer cells. Molecular docking showed strong interaction between ACTD and MDM2/MDMX. Meanwhile, LDActD significantly decreased P53-MDM2 complex. Significant increase of the apoptotic activity by the combination therapy in KB cells is P53 upregulated modulator of apoptosis (PUMA) dependent. In addition to the decrease in MMP, LDActD increased P53 regulated protein and decreased BCL-XL in KB cells. LDActD efficiently enhanced the cytotoxicity of CDDP in cancer cells and induced P53-PUMA-dependent and mitochondria-mediated apoptosis in KB cells. The reactivation of P53 was probably achieved by disturbing the interaction of P53 and MDM2/MDMX.

Evaluating the Stability of mRNAs and Noncoding RNAs

Changes in RNA stability have an important impact in the gene expression regulation. Different methods based on the transcription blockage with RNA polymerase inhibitors or metabolic labeling of newly synthesized RNAs have been developed to evaluate RNA decay rates in cultured cell. Combined with techniques to measure transcript abundance genome-wide, these methods have been used to reveal novel features of the eukaryotic transcriptome. The stability of protein-coding mRNAs is in general closely associated to the physiological function of their encoded proteins, with short-lived mRNAs being significantly enriched among regulatory genes whereas genes associated with housekeeping functions are predominantly stable. Likewise, the stability of noncoding RNAs (ncRNAs) seems to reflect their functional role in the cell. Thus, investigating RNA stability can provide insights regarding the function of yet uncharacterized regulatory ncRNAs. In this chapter, we discuss the methodologies currently used to estimate RNA decay and outline an experimental protocol for genome-wide estimation of RNA stability of protein-coding and lncRNAs. This protocol details the transcriptional blockage of cultured cells with actinomycin D, followed by RNA isolation at different time points, the determination of transcript abundance by qPCR/DNA oligoarray hybridization, and the calculation of individual transcript half-lives.

Are different methotrexate regimens as first line therapy for low risk gestational trophoblastic neoplasia more cost effective than the dactinomycin regimen used in GOG 0174?

OBJECTIVES

Gynecologic Oncology Group (GOG) 0174 compared weekly intramuscular methotrexate (MTX) with biweekly pulsed intravenous dactinomycin (Act-D) as single-agent chemotherapy for low-risk gestational trophoblastic neoplasia (GTN). Act-D had a higher rate of initial complete response (CR) (70% vs. 53%, p=0.01), but multi-day regimens of MTX have higher historic success rates. We assessed the cost-effectiveness of Act-D vs. MTX per GOG 0174 and explored multi-day MTX regimens.

METHODS

A cost effectiveness decision model was constructed with data from GOG 0174. Outcome was cost per first-line treatment success expressed in terms of incremental cost-effectiveness ratio (ICER). Front-line failures were assumed to receive cross-over single agent therapy, second line failures; multi-agent chemotherapy. GOG 0174 had no quality of life (QOL) evaluation, so equal QOL (utility 1.0) was assumed but varied in sensitivity analysis. A second exploratory model included 5-day and 8-day MTX regimens.

RESULTS

Act-D ($18,505) was more expensive compared to weekly MTX ($8950) with an ICER of $56,215 per first-line treatment success compared to weekly MTX. Small decreases in QOL dramatically increased the ICER during sensitivity analysis. Models with multi-day MTX regimens were also more cost-effective than Act-D. If effectiveness was redefined as avoidance of multi-agent chemotherapy, weekly MTX was more effective.

CONCLUSIONS

With a complete cure rate for low-risk GTN regardless of initial agent, our model supports provider hesitation toward first line Act-D for low risk GTN. While Act-D is more effective for first line treatment success, it is more costly, and does not decrease rate of multi-agent chemotherapy use.

Regulatory role of rpL3 in cell response to nucleolar stress induced by Act D in tumor cells lacking functional p53

Many chemotherapeutic drugs cause nucleolar stress and p53-independent pathways mediating the nucleolar stress response are emerging. Here, we demonstrate that ribosomal stress induced by Actinomycin D (Act D) is associated to the up-regulation of ribosomal protein L3 (rpL3) and its accumulation as ribosome-free form in lung and colon cancer cell lines devoid of p53. Free rpL3 regulates p21 expression at transcriptional and post-translational levels through a molecular mechanism involving extracellular-signal-regulated kinases1/2 (ERK1/2) and mouse double minute-2 homolog (MDM2). Our data reveal that rpL3 participates to cell response acting as a critical regulator of apoptosis and cell migration. It is noteworthy that silencing of rpL3 abolishes the cytotoxic effects of Act D suggesting that the loss of rpL3 makes chemotherapy drugs ineffective while rpL3 overexpression associates to a strong increase of Act D-mediated inhibition of cell migration. Taking together our results show that the efficacy of Act D chemotherapy depends on rpL3 status revealing new specific targets involved in the molecular pathways activated by Act D in cancers lacking of p53. Hence, the development of treatments aimed at upregulating rpL3 may be beneficial for the treatment of these cancers.

Identification of early gene expression changes in primary cultured neurons treated with topoisomerase I poisons

Topoisomerase 1 (TOP1) poisons like camptothecin (CPT) are currently used in cancer chemotherapy but these compounds can have damaging, off-target effects on neurons leading to cognitive, sensory and motor deficits. To understand the molecular basis for the enhanced sensitivity of neurons to CPT, we examined the effects of compounds that inhibit TOP1-CPT, actinomycin D (ActD) and β-lapachone (β-Lap)-on primary cultured rat motor (MN) and cortical (CN) neurons as well as fibroblasts. Neuronal cells expressed higher levels of Top1 mRNA than fibroblasts but transcript levels are reduced in all cell types after treatment with CPT. Microarray analysis was performed to identify differentially regulated transcripts in MNs in response to a brief exposure to CPT. Pathway analysis of the differentially expressed transcripts revealed activation of ERK and JNK signaling cascades in CPT-treated MNs. Immediate-early genes like Fos, Egr-1 and Gadd45b were upregulated in CPT-treated MNs. Fos mRNA levels were elevated in all cell types treated with CPT; Egr-1, Gadd45b and Dyrk3 transcript levels, however, increased in CPT-treated MNs and CNs but decreased in CPT-treated fibroblasts. These transcripts may represent new targets for the development of therapeutic agents that mitigate the off-target effects of chemotherapy on the nervous system.

Streptomyces-derived actinomycin D inhibits biofilm formation by Staphylococcus aureus and its hemolytic activity

Staphylococcus aureus is a versatile human pathogen that produces diverse virulence factors, and its biofilm cells are difficult to eradicate due to their inherent ability to tolerate antibiotics. The anti-biofilm activities of the spent media of 252 diverse endophytic microorganisms were investigated using three S. aureus strains. An attempt was made to identify anti-biofilm compounds in active spent media and to assess their anti-hemolytic activities and hydrophobicities in order to investigate action mechanisms. Unlike other antibiotics, actinomycin D (0.5 μg ml(-1)) from Streptomyces parvulus significantly inhibited biofilm formation by all three S. aureus strains. Actinomycin D inhibited slime production in S. aureus and it inhibited hemolysis by S. aureus and caused S. aureus cells to become less hydrophobic, thus supporting its anti-biofilm effect. In addition, surface coatings containing actinomycin D prevented S. aureus biofilm formation on glass surfaces. Given these results, FDA-approved actinomycin D warrants further attention as a potential antivirulence agent against S. aureus infections.

RRP12 is a crucial nucleolar protein that regulates p53 activity in osteosarcoma cells

RRP12 (ribosomal RNA processing 12 homolog), a nucleolar protein, plays important roles in cell cycle progression and the response to deoxyribonucleic acid (DNA) damage in yeast cells. However, its role has not been investigated in mammalian cells that possess p53, which has close functional association to nucleolus. We explored the role of RRP12 in nucleolar stress condition using an osteosarcoma cell line, U2OS. To induce DNA damage and nucleolar disruption, two cytotoxic drugs, doxorubicin and actinomycin D were used. Cytotoxic stress resulted nucleolar disruption induced cell cycle arrest and apoptosis in U2OS cells. However, RRP12 overexpression promoted resistance to cytotoxic stress. In contrast, RRP12 silencing enhanced susceptibility to cytotoxic stress. During drug treatment, p53 activity and cell death were suppressed by RRP12 overexpression but promoted by RRP12 silencing. This study demonstrated that RRP12 was crucial for cell survival during cytotoxic stress via the repression of p53 stability. Thus, targeting RRP12 may enhance chemotherapeutic effect in cancers.

Investigating actinomycin D binding to G-quadruplex, i-motif and double-stranded DNA in 27-nt segment of c-MYC gene promoter

c-MYC DNA is an attractive target for drug design, especially for cancer chemotherapy. Around 90% of c-MYC transcription is controlled by NHE III1, whose 27-nt purine-rich strand has the ability to form G-quadruplex structure. In this investigation, interaction of ActD with 27-nt G-rich strand (G/c-MYC) and its equimolar mixture with the complementary sequence, (GC/c-MYC) as well as related C-rich oligonucleotide (C/c-MYC) was evaluated. Molecular dynamic simulations showed that phenoxazine and lactone rings of ActD come close to the outer G-tetrad nucleotides indicating that ActD binds through end-stacking to the quadruplex DNA. RMSD and RMSF revealed that fluctuation of the quadruplex DNA increases upon interaction with the drug. The results of spectrophotometry and spectrofluorometry indicated that ActD most probably binds to the c-MYC quadruplex and duplex DNA via end-stacking and intercalation, respectively and polarity of ActD environment decreases due to the interaction. It was also found that binding of ActD to the GC-rich DNA is stronger than the two other forms of DNA. Circular dichroism results showed that the type of the three forms of DNA structures doesn't change, but their compactness alters due to their interaction with ActD. Finally, it can be concluded that ActD binds differently to double stranded DNA, quadruplex DNA and i-motif.

Accumulation of long-lived mRNAs associated with germination in embryos during seed development of rice

Mature dry seeds contain translatable mRNAs called long-lived mRNAs. Early studies have shown that protein synthesis during the initial phase of seed germination occurs from long-lived mRNAs, without de novo transcription. However, the gene expression systems that generate long-lived mRNAs in seeds are not well understood. To examine the accumulation of long-lived mRNAs in developing rice embryos, germination tests using the transcriptional inhibitor actinomycin D (Act D) were performed with the Japonica rice cultivar Nipponbare. Although over 70% of embryos at 10 days after flowering (DAF) germinated in the absence of the inhibitor, germination was remarkably impaired in embryos treated with Act D. In contrast, more than 70% of embryos at 20, 25, 30 and 40 DAF germinated in the presence of Act D. The same results were obtained when another cultivar, Koshihikari, was used, indicating that the long-lived mRNAs required for germination predominantly accumulate in embryos between 10 and 20 DAF during seed development. RNA-Seq identified 529 long-lived mRNA candidates, encoding proteins such as ABA, calcium ion and phospholipid signalling-related proteins, and HSP DNA J, increased from 10 to 20 DAF and were highly abundant in 40 DAF embryos of Nipponbare and Koshihikari. We also revealed that these long-lived mRNA candidates are clearly up-regulated in 10 DAF germinating embryos after imbibition, suggesting that the accumulation of these mRNAs in embryos is indispensable for the induction of germination. The findings presented here may facilitate in overcoming irregular seed germination or producing more vigorous seedlings.

Actinomycin D inhibits cell proliferations and promotes apoptosis in osteosarcoma cells

Actinomycin D (ActD), a well known transcription inhibitors, has been widely reported to induce cell apoptosis in several types of tumor cells by inhibiting the anti-apoptotic gene transcriptions. However, how ActD affects osteosarcoma cells survival and its molecular mechanism is currently unclear. In the present study, results of proliferation assays and Hoechst stainings suggested that MG63 human osteosarcoma cells showed impaired cell proliferations and significant apoptosis after ActD treatment. Moreover, biochemical results showed that cleaved caspase-3 is gradually increased with the increasing ActD concentrations and treated times. Importantly, results of western blots indicated that protein levels of cyclin factors, such as cyclin A, D1 and E, were all reduced after ActD treatment. And ActD treatments may inhibit mRNA transcription levels of these cyclin factors, which may finally lead to cell cycle arrest and consequently apoptosis. The present study have revealed a novel mechanism by which ActD inhibits osteosarcoma cell proliferations and induces apoptosis, and will provide an useful clue to chemotherapy in future treatment of osteosarcoma.

Comparison of the efficacy of methotrexate and actinomycin D in the treatment of patients with stage I low risk gestational trophoblastic neoplasia (GTN)

BACKGROUND

Gestational trophoblastic neoplasia (GTN) refers to malignant lesions that arise from abnormal proliferation of placental trophoblast. Even in its metastatic forms GTN is curable with a cure rate of 90-100 %. Currently, methotrexate with or without folic acid, andactinomycin D is recommended for low risk GTN. The aim of this study is to compare the efficacy of methotrexate and actinomycin D as the first-line single chemotherapeutic agents for women with low-risk gestational trophoblastic neoplasia (LR-GTN).

METHODS

A total of 30 women with LR-GTN were randomized to receive a weekly pulsed dose of 40 mg/m (2) of methotrexate intramuscularly (n=15) or a pulsed intravenous bolus of 1.25 mg/m (2) of actinomycin D every 2 weeks (n=15). An additional cycle was administered as consolidation treatment following normalization of the serum level of beta-human chorionic gonadotropin (˂10 IU/L).

RESULTS

Complete remission was achieved in 53.3% of patients in the methotrexate group and 86.7% in the actinomycin D group (p˂0.04). The mean number of treatment cycles needed to achieve response was lower in the actinomycin D group (4.3 vs. 6.5). The mean duration from beginning of treatment till achieving complete remission was 9.6 weeks for the Act group and 13 weeks for the MTX group.

CONCLUSION

Actinomycin D may be a better option than methotrexate as a first-line chemotherapy agent for patients with LR-GTN but larger multicenter randomized controlled trials should be conducted to establish the most appropriate regimen for these patients.

Ribonuclease II preserves chloroplast RNA homeostasis by increasing mRNA decay rates, and cooperates with polynucleotide phosphorylase in 3' end maturation

Ribonuclease R (RNR1) and polynucleotide phosphorylase (cpPNPase) are the two known 3'→5' exoribonucleases in Arabidopsis chloroplasts, and are involved in several aspects of rRNA and mRNA metabolism. In this work, we show that mutants lacking both RNR1 and cpPNPase exhibit embryo lethality, akin to the non-viability of the analogous double mutant in Escherichia coli. We were successful, however, in combining an rnr1 null mutation with weak pnp mutant alleles, and show that the resulting chlorotic plants display a global reduction in RNA abundance. Such a counterintuitive outcome following the loss of RNA degradation activity suggests a major importance of RNA maturation as a determinant of RNA stability. Detailed analysis of the double mutant demonstrates that the enzymes catalyze a two-step maturation of mRNA 3' ends, with RNR1 polishing 3' termini created by cpPNPase. The bulky quaternary structure of cpPNPase compared with RNR1 could explain this activity split between the two enzymes. In contrast to the double mutants, the rnr1 single mutant overaccumulates most mRNA species when compared with the wild type. The excess mRNAs in rnr1 are often present in non-polysomal fractions, and half-life measurements demonstrate a substantial increase in the stability of most mRNA species tested. Together, our data reveal the cooperative activity of two 3'→5' exoribonucleases in chloroplast mRNA 3' end maturation, and support the hypothesis that RNR1 plays a significant role in the destabilization of mRNAs unprotected by ribosomes.