Human Papillomavirus-Associated Anogenital Pathology in Females With HPV-Positive Oropharyngeal Squamous Cell Carcinoma

We sought to determine the incidence and location of human papillomavirus (HPV)-associated anogenital disease in women with HPV-positive oropharyngeal squamous cell carcinoma (OPSCC) via a retrospective cohort study with prospective contact to update history at Mayo Clinic in Rochester, Minnesota. Females undergoing treatment for nonmetastatic HPV-positive OPSCC from 2011 to 2019 were identified. Clinical history and outcomes were abstracted from medical records. Patients without documented anogenital history were contacted, consented, and administered a survey, and external records were requested and reviewed. Seventeen of 46 patients (37.0%) had a history of anogenital HPV-associated disease, and 16 of 17 (94.1%) required procedures to diagnose or treat HPV lesions. The cervix was the most common site (16/17, 94.1%). Procedures included colposcopy (n = 6), cervical excision (n = 3), cryotherapy (n = 4), and hysterectomy (n = 3). One case of fatal cervical carcinoma was noted, diagnosed 1 year following OPSCC. Three of 17 (17.6%) had HPV-related vulvovaginal disease, and 1 of 17 had anal disease. Patients with a history of HPV-positive OPSCC may be at elevated risk for HPV-associated anogenital disease.

A phase I trial of nab-paclitaxel/bevacizumab (AB160) nano-immunoconjugate therapy for metastatic gynecological malignancies: MC1371 (NCT02020707)

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Background: AB160 is a 160 nm nano-immunoconjugate consisting of nab-paclitaxel (NP) nanoparticles non-covalently coated with bevacizumab (BEV) for targeted delivery into tissues expressing high levels of vascular-endothelial growth factor (VEGF). Both taxanes (GOG-0129C, GOG-0126R, GOG-0127V) and BEV (GOG-0229E, AURELIA, GOG-0227C) have demonstrated clinical activity in previously treated metastatic endometrial cancer (EC), ovarian cancer (OC), and cervical cancer (CC), respectively. Methods: A 3+3 phase I trial was conducted in patients with EC, platinum-resistant OC and CC who had prior systemic treatment for metastatic disease to determine the maximum tolerated dose of AB160 administered intravenously on days 1, 8 and 15 of a 28-day cycle. The starting dose level (DL1) was NP at 125 mg/m2 with BEV at 50 mg/m2. There were 2 higher dose levels: DL2 (NP at 150 mg/m2 with BEV at 60 mg/m2) and DL3 (NP at 175 mg/m2 with BEV at 70 mg/m2). Dose limiting toxicities (DLT) included grade (G) 4 neutropenia or anemia, PLT < 25,000, serum creatinine ≥2 times baseline, G2-4 neurologic toxicity or G3-4 non-hematologic toxicities. Disease evaluations were conducted after every 2 treatment cycles using RECIST criteria. Patients were treated until disease progression or intolerability. Samples were collected for pharmacokinetic (PK) studies. Results: Nine women 41 – 74 years of age (median 57) have enrolled (5 with EC and 4 with OC); data are available for the first 8. No DLTs have been observed among the 3 women enrolled on DL1, 3 women on DL2, and 2 women on DL3. All 3 patients on DL3 continue on treatment. The other 6 patients have discontinued due to adverse reactions (3), progression (2), and patient choice (1). The median number of cycles administered is 6 (4-14). The most common severe (G3/4) toxicities include neutropenia (37.5%) and leukopenia (25%). There have been 5 partial responses (62.5%): 1 on DL1 and 2 each on DL2 and DL3. PK evaluation is pending. Conclusions: AB160 therapy is safe and demonstrates promising clinical activity in patients with previously treated metastatic gynecologic malignancies. Further clinical testing is being pursued in this patient population. Clinical trial information: NCT02020707.

External beam radiotherapy versus vaginal brachytherapy in patients with stage II endometrial cancer: a systematic review and meta-analysis

Objective

The choice of adjuvant treatment for women with stage II endometrial cancer is challenging, given the known increase in morbidity with external beam radiation compared with vaginal brachytherapy, and the lack of consensus on its benefits. We summarized the evidence on survival and recurrence for stage II endometrial cancer, defined as cervical stromal invasion, after adjuvant postoperative external beam radiotherapy and vaginal brachytherapy.

Methods

We searched the MEDLINE, EMBASE, CENTRAL, and Scopus databases from inception to January 2019 to identify studies that compared adjuvant postoperative external beam radiotherapy with or without vaginal brachytherapy and vaginal brachytherapy alone in stage II endometrial cancer. Our primary outcome was the locoregional recurrence rate, defined as recurrence in the pelvis or vagina. Secondary outcomes included the rate of recurrence at any site, distant recurrence rate, vaginal recurrence rate, pelvic recurrence rate, and 5 year overall survival. Study selection, assessment, and data abstraction were performed by an independent set of reviewers. Random effects models were used to synthesize quantitative data.

Results

We included 15 cohort studies reporting data on 1070 women. Most women with stage II endometrial cancer (848/1070, 79.3%) were treated with external beam radiotherapy with or without vaginal brachytherapy. Subgroup analysis was stratified by whether >90% of the women included underwent pelvic lymph node assessment (sampling or full dissection). Locoregional recurrence (pelvic and vaginal recurrence) was significantly reduced with external beam radiotherapy with or without vaginal brachytherapy compared with vaginal brachytherapy alone (14 studies (n=1057); odds ratio (OR) 0.33 (95% confidence interval (CI) 0.16 to 0.68); I2=5%) regardless of pelvic lymph node assessment. Most women (81.8%) who recurred locoregionally had a least one uterine risk factor (grade 3 tumor, myometrial invasion >50%, or lymphovascular invasion). There was no difference in overall survival with external beam radiotherapy with or without vaginal brachytherapy compared with vaginal brachytherapy alone (five studies (n=463); OR 0.78 (95% CI 0.34 to 1.80); I2=48%).

Conclusions

External beam radiotherapy with or without vaginal brachytherapy decreased the locoregional recurrence threefold for stage II endometrial cancer, regardless of pelvic lymph node assessment. Most women who suffered recurrence locoregionally had a least one high risk factor. Vaginal brachytherapy alone may be sufficient therapy for node negative stage II endometrial cancer without uterine risk factors, while those with uterine risk factors should be considered for external beam radiotherapy with or without vaginal brachytherapy to improve locoregional control.

Sentinel lymph node biopsy for robotic-assisted endometrial cancer staging: further improvement of perioperative outcomes

Objectives

It is unclear if sentinel lymph node biopsy is associated with improved surgical outcomes compared with lymphadenectomy in patients with endometrial cancer. In this study we aimed to compare peri-operative surgical outcomes and treatment-related morbidity in patients who underwent robotic-assisted sentinel lymph node biopsy versus systematic pelvic lymphadenectomy or hysterectomy alone for apparent early-stage endometrial cancer.

Methods

Records were reviewed of consecutive patients with International Federation of Gynecology and Obstetrics stages I–III endometrial cancer undergoing robotic-assisted staging from January 1, 2009, through June 30, 2016. For the purpose of this analysis we focused on the actual patients who had sentinel node biopsy only (ie, excluding those who had an associated lymphadenectomy either for failed mapping or during the learning curve). We also excluded patients who had para-aortic lymph node dissection from the lymphadenectomy group. Perioperative and 30-day surgical outcomes were compared between patients who underwent sentinel lymph node assessment and those who had pelvic lymphadenectomy or hysterectomy alone, respectively. Inverse probability of treatment weighting derived from propensity scores was used to minimize allocation bias in the comparison of outcomes between groups.

Results

A total of 621 patients were analyzed: 188 (30.3%) with sentinel lymph node biopsy, 198 (31.9%) with pelvic lymphadenectomy, and 235 (37.8%) with hysterectomy alone. Inverse probability of treatment weights analysis balanced for baseline characteristics (age, body mass index, American Society of Anesthesiologists score, Charlson co-morbidity index, parity, prior cesarean section, and previous abdominal operation) showed no significant differences in intra-operative and post-operative complications, re-admissions, and re-operations between the groups. Compared with pelvic lymphadenectomy, the sentinel lymph node biopsy group had a shorter mean operative time (138.0 vs 222.8 min, p<0.001) and less median blood loss (50 vs 100 mL, p<0.001). Sentinel lymph node biopsy also was not associated with worse morbidity compared with hysterectomy alone.

Conclusions

Introduction of sentinel lymph node biopsy reduces operative times and improves peri-operative surgical outcomes of robotic-assisted staging for apparent early-stage endometrial cancer without worsening the morbidity of hysterectomy alone.

Guidelines for perioperative care in gynecologic/oncology: Enhanced Recovery After Surgery (ERAS) Society recommendations-2019 update

BACKGROUND

This is the first updated Enhanced Recovery After Surgery (ERAS) Society guideline presenting a consensus for optimal perioperative care in gynecologic/oncology surgery.

METHODS

A database search of publications using Embase and PubMed was performed. Studies on each item within the ERAS gynecologic/oncology protocol were selected with emphasis on meta-analyses, randomized controlled trials, and large prospective cohort studies. These studies were then reviewed and graded according to the Grading of Recommendations, Assessment, Development and Evaluation (GRADE) system.

RESULTS

All recommendations on ERAS protocol items are based on best available evidence. The level of evidence for each item is presented accordingly.

CONCLUSIONS

The updated evidence base and recommendation for items within the ERAS gynecologic/oncology perioperative care pathway are presented by the ERAS® Society in this consensus review.

Does adjuvant chemotherapy dose modification have an impact on the outcome of patients diagnosed with advanced stage ovarian cancer? An NRG Oncology/Gynecologic Oncology Group study

PURPOSE

To determine the relationship between chemotherapy dose modification (dose adjustment or treatment delay), overall survival (OS) and progression-free survival (PFS) for women with advanced-stage epithelial ovarian carcinoma (EOC) and primary peritoneal carcinoma (PPC) who receive carboplatin and paclitaxel.

METHODS

Women with stages III and IV EOC and PPC treated on the Gynecologic Oncology Group phase III trial, protocol 182, who completed eight cycles of carboplatin with paclitaxel were evaluated in this study. The patients were grouped per dose modification and use of granulocyte colony stimulating factor (G-CSF). The primary end point was OS; Hazard ratios (HR) for PFS and OS were calculated for patients who completed eight cycles of chemotherapy. Patients without dose modification were the referent group. All statistical analyses were performed using the R programming language and environment.

RESULTS

A total of 738 patients were included in this study; 229 (31%) required dose modification, 509 did not. The two groups were well-balanced for demographic and prognostic factors. The adjusted hazard ratios (HR) for disease progression and death among dose-modified patients were: 1.43 (95% CI, 1.19-1.72, P < 0.001) and 1.26 (95% CI, 1.04-1.54, P = 0.021), respectively. Use of G-CSF was more frequent in dose-modified patients with an odds ratio (OR) of 3.63 (95% CI: 2.51-5.26, P < 0.001) compared to dose-unmodified patients.

CONCLUSION

Dose-modified patients were at a higher risk of disease progression and death. The need for chemotherapy dose modification may identify patients at greater risk for adverse outcomes in advanced stage EOC and PPC.

Frozen Section for Detection of Lymph Nodes After Cervical Injection with Indocyanine Green (ICG) for Sentinel Lymph Node Technique in Endometrial Cancer Staging

OBJECTIVE

The aim of this study was to assess the role of frozen section (FS) in identifying an absence of lymph nodes during sentinel lymph node (SLN) biopsy for apparent early-stage endometrial cancer (EC).

METHODS

Consecutive apparent early-stage EC patients who had SLNs removed after cervical injection with indocyanine green (ICG) from 1 June 2014 to 30 June 2016 were analyzed. An empty node (EN) was defined as an SLN specimen without evidence of lymph node(s). The association of tumor and patient characteristics with an EN was evaluated, and trend analysis to compare the rate of ENs over calendar quarters was performed. A decision-tree model was then created to compare the use of FS versus no FS for SLN evaluation in the hypothetical cohort affected by early-stage EC in the US each year.

RESULTS

Over the study period, 300 patients met the inclusion criteria. FS revealed ENs in 24 (8%) patients. No association between patient demographic characteristics (age, body mass index, prior abdominopelvic surgery, international federation of gynecology and obstetrics (FIGO) stage, histology, myometrial invasion, cervical stromal invasion) and presence of ENs was observed. The rate of ENs at FS did not change over time (p = 0.68). The hypothetical analysis showed a 4.3% decrease of inappropriately staged patients with the use of FS on the SLN (95% confidence interval 4.1-4.5).

CONCLUSIONS

ENs during SLN biopsy for EC staging is not a rare event and can be easily detected with FS. The implementation of FS of SLN might reduce inadequate staging of EC. Individual institutions may want to examine their own EN rates and determine if this would assist them in their SLN practices for EC.

Mutations in Homologous Recombination Genes and Outcomes in Ovarian Carcinoma Patients in GOG 218: An NRG Oncology/Gynecologic Oncology Group Study

Purpose: We hypothesized that mutations in homologous recombination repair (HRR) genes beyond BRCA1 and BRCA2 improve outcomes for ovarian carcinoma patients treated with platinum therapy and would impact the relative benefit of adding prolonged bevacizumab.Experimental Design: We sequenced DNA from blood and/or neoplasm from 1,195 women enrolled in GOG-0218, a randomized phase III trial in advanced ovarian carcinoma of bevacizumab added to carboplatin and paclitaxel. Defects in HRR were defined as damaging mutations in 16 genes. Proportional hazards models were used to estimate relative hazards for progression-free survival (PFS) and overall survival (OS).Results: Of 1,195 women with ovarian carcinoma, HRR mutations were identified in 307 (25.7%). Adjusted hazards for progression and death compared with those without mutations were lower for women with non-BRCA HRR mutations [HR = 0.73; 95% confidence interval (CI), 0.57-0.94; P = 0.01 for PFS; HR = 0.67; 95% CI, 0.50-0.90; P = 0.007 for OS] and BRCA1 mutations (HR = 0.80; 95% CI, 0.66-0.97; P = 0.02 for PFS; HR = 0.74; 95% CI, 0.59-0.94; P = 0.01 for OS) and were lowest for BRCA2 mutations (HR = 0.52; 95% CI, 0.40-0.67; P < 0.0001 for PFS; HR = 0.36; 95% CI, 0.25-0.53; P < 0.0001 for OS). A test of interaction showed no difference in the effect of bevacizumab on PFS between cases with and without mutations.Conclusions: HRR mutations, including non-BRCA genes, significantly prolong PFS and OS in ovarian carcinoma and should be stratified for in clinical trials. The benefit of adding bevacizumab was not significantly modified by mutation status. Clin Cancer Res; 24(4); 777-83. ©2017 AACR.

Conventional chemotherapy and oncogenic pathway targeting in ovarian carcinosarcoma using a patient-derived tumorgraft

Ovarian carcinosarcoma is a rare subtype of ovarian cancer with poor clinical outcomes. The low incidence of this disease makes accrual to large clinical trials challenging. However, studies have shown that treatment responses in patient-derived xenograft (PDX) models correlate with matched-patient responses in the clinic, supporting their use for preclinical testing of standard and novel therapies. An ovarian carcinosarcoma PDX is presented herein and showed resistance to carboplatin and paclitaxel (similar to the patient) but exhibited significant sensitivity to ifosfamide and paclitaxel. The PDX demonstrated overexpression of EGFR mRNA and gene amplification by array comparative genomic hybridization (log2 ratio 0.399). EGFR phosphorylation was also detected. Angiogensis and insulin-like growth factor pathways were also implicated by overexpression of VEGFC and IRS1. In order to improve response to chemotherapy, the PDX was treated with carboplatin/paclitaxel with or without a pan-HER and VEGF inhibitor (BMS-690514) but there was no tumor growth inhibition or improved animal survival, which may be explained by a KRAS mutation. Resistance was also observed when the IGF-1R inhibitor BMS-754807 was combined with carboplatin/paclitaxel. Because poly (ADP-ribose) polymerase inhibitors have activity in ovarian cancer patients, with and without BRCA mutations, ABT-888 was also tested but found to have no activity. Pathogenic mutations were also detected in TP53 and PIK3CA. In conclusion, ifosfamide/paclitaxel was superior to carboplatin/paclitaxel in this ovarian carcinosarcoma PDX and gene overexpression or amplification alone was not sufficient to predict response to targeted therapy. Better predictive markers of response are needed.

Development of a prediction model for residual disease in newly diagnosed advanced ovarian cancer

OBJECTIVES

To construct a tool, using computed tomography (CT) imaging and preoperative clinical variables, to estimate successful primary cytoreduction for advanced epithelial ovarian cancer (EOC).

METHODS

Women who underwent primary cytoreductive surgery for stage IIIC/IV EOC at Mayo Clinic between 1/2/2003 and 12/30/2011 and had preoperative CT images of the abdomen and pelvis within 90days prior to their surgery available for review were included. CT images were reviewed for large-volume ascites, diffuse peritoneal thickening (DPT), omental cake, lymphadenopathy (LP), and spleen or liver involvement. Preoperative factors included age, body mass index (BMI), Eastern Cooperative Oncology Group performance status (ECOG PS), American Society of Anesthesiologists (ASA) score, albumin, CA-125, and thrombocytosis. Two prediction models were developed to estimate the probability of (i) complete and (ii) suboptimal cytoreduction (residual disease (RD) >1cm) using multivariable logistic analysis with backward and stepwise variable selection methods. Internal validation was assessed using bootstrap resampling to derive an optimism-corrected estimate of the c-index.

RESULTS

279 patients met inclusion criteria: 143 had complete cytoreduction, 26 had suboptimal cytoreduction (RD>1cm), and 110 had measurable RD ≤1cm. On multivariable analysis, age, absence of ascites, omental cake, and DPT on CT imaging independently predicted complete cytoreduction (c-index=0.748). Conversely, predictors of suboptimal cytoreduction were ECOG PS, DPT, and LP on preoperative CT imaging (c-index=0.685).

CONCLUSIONS

The generated models serve as preoperative evaluation tools that may improve counseling and selection for primary surgery, but need to be externally validated.

A phase II study of gemcitabine in combination with tanespimycin in advanced epithelial ovarian and primary peritoneal carcinoma

OBJECTIVE

To evaluate the efficacy and biological effects of the gemcitabine/tanespimycin combination in patients with advanced ovarian and peritoneal cancer. To assess the effect of tanespimycin on tumor cells, levels of the chaperone proteins HSP90 and HSP70 were examined in peripheral blood mononuclear cells (PBMC) and paired tumor biopsy lysates.

METHODS

Two-cohort phase II clinical trial. Patients were grouped according to prior gemcitabine therapy. All participants received tanespimycin 154 mg/m(2) on days 1 and 9 of cycle 1 and days 2 and 9 of subsequent cycles. Patients also received gemcitabine 750 mg/m(2) on day 8 of the first treatment cycle and days 1 and 8 of subsequent cycles.

RESULTS

The tanespimycin/gemcitabine combination induced a partial response in 1 gemcitabine naïve patient and no partial responses in gemcitabine resistant patients. Stable disease was seen in 6 patients (2 gemcitabine naïve and 4 gemcitabine resistant). The most common toxicities were hematologic (anemia and neutropenia) as well as nausea and vomiting. Immunoblotting demonstrated limited upregulation of HSP70 but little or no change in levels of most client proteins in PBMC and paired tumor samples.

CONCLUSIONS

Although well tolerated, the tanespimycin/gemcitabine combination exhibited limited anticancer activity in patients with advanced epithelial ovarian and primary peritoneal carcinoma, perhaps because of failure to significantly downregulate the client proteins at clinically achievable exposures.

Programmed cell death in Escherichia coli: some antibiotics can trigger mazEF lethality

The discovery of toxin-antitoxin gene pairs (also called addiction modules) on extrachromosomal elements of Escherichia coli, and particularly the discovery of homologous modules on the bacterial chromosome, suggest that a potential for programmed cell death may be inherent in bacterial cultures. We have reported on the E. coli mazEF system, a regulatable addiction module located on the bacterial chromosome. MazF is a stable toxin and MazE is a labile antitoxin. Here we show that cell death mediated by the E. coli mazEF module can be triggered by several antibiotics (rifampicin, chloramphenicol, and spectinomycin) that are general inhibitors of transcription and/or translation. These antibiotics inhibit the continuous expression of the labile antitoxin MazE, and as a result, the stable toxin MazF causes cell death. Our results have implications for the possible mode(s) of action of this group of antibiotics.

The regulation of the Escherichia coli mazEF promoter involves an unusual alternating palindrome

The Escherichia coli mazEF system is a chromosomal "addiction module" that, under starvation conditions in which guanosine-3',5'-bispyrophosphate (ppGpp) is produced, is responsible for programmed cell death. This module specifies for the toxic stable protein MazF and the labile antitoxic protein MazE. Upstream from the mazEF module are two promoters, P(2) and P(3) that are strongly negatively autoregulated by MazE and MazF. We show that the expression of this module is positively regulated by the factor for inversion stimulation. What seems to be responsible for the negative autoregulation of mazEF is an unusual DNA structure, which we have called an "alternating palindrome." The middle part, "a," of this structure may complement either the downstream fragment, "b," or the upstream fragment, "c". When the MazE.MazF complex binds either of these arms of the alternating palindrome, strong negative autoregulation results. We suggest that the combined presence of the two promoters, the alternating palindrome structure and the factor for inversion stimulation-binding site, all permit the expression of the mazEF module to be sensitively regulated under various growth conditions.

Regulation of Escherichia coli RelA requires oligomerization of the C-terminal domain

The E. coli RelA protein is a ribosome-dependent (p)ppGpp synthetase that is activated in response to amino acid starvation. RelA can be dissected both functionally and physically into two domains: The N-terminal domain (NTD) (amino acids [aa] 1 to 455) contains the catalytic domain of RelA, and the C-terminal domain (CTD) (aa 455 to 744) is involved in regulating RelA activity. We used mutational analysis to localize sites important for RelA activity and control in these two domains. We inserted two separate mutations into the NTD, which resulted in mutated RelA proteins that were impaired in their ability to synthesize (p)ppGpp. When we caused the CTD in relA(+) cells to be overexpressed, (p)ppGpp accumulation during amino acid starvation was negatively affected. Mutational analysis showed that Cys-612, Asp-637, and Cys-638, found in a conserved amino acid sequence (aa 612 to 638), are essential for this negative effect of the CTD. When mutations corresponding to these residues were inserted into the full-length relA gene, the mutated RelA proteins were impaired in their regulation. In attempting to clarify the mechanism through which the CTD regulates RelA activity, we found no evidence for competition for ribosomal binding between the normal RelA and the overexpressed CTD. Results from CyaA complementation experiments of the bacterial two-hybrid system fusion plasmids (G. Karimova, J. Pidoux, A. Ullmann, and D. Ladant, Proc. Natl. Acad. Sci. USA 95:5752-5756, 1998) indicated that the CTD (aa 564 to 744) is involved in RelA-RelA interactions. Our findings support a model in which RelA activation is regulated by its oligomerization state.

Addiction modules and programmed cell death and antideath in bacterial cultures

In bacteria, programmed cell death is mediated through "addiction modules" consisting of two genes. The product of the second gene is a stable toxin, whereas the product of the first is a labile antitoxin. Here we extensively review what is known about those modules that are borne by one of a number of Escherichia coli extrachromosomal elements and are responsible for the postsegregational killing effect. We focus on a recently discovered chromosomally borne regulatable addiction module in E. coli that responds to nutritional stress and also on an antideath gene of the E. coli bacteriophage lambda. We consider the relation of these two to programmed cell death and antideath in bacterial cultures. Finally, we discuss the similarities between basic features of programmed cell death and antideath in both prokaryotes and eukaryotes and the possibility that they share a common evolutionary origin.

rexB of bacteriophage lambda is an anti-cell death gene

In Escherichia coli, programmed cell death is mediated through "addiction modules" consisting of two genes; the product of one gene is long-lived and toxic, whereas the product of the other is short-lived and antagonizes the toxic effect. Here we show that the product of lambdarexB, one of the few genes expressed in the lysogenic state of bacteriophage lambda, prevents cell death directed by each of two addiction modules, phd-doc of plasmid prophage P1 and the rel mazEF of E. coli, which is induced by the signal molecule guanosine 3',5'-bispyrophosphate (ppGpp) and thus by amino acid starvation. lambdaRexB inhibits the degradation of the antitoxic labile components Phd and MazE of these systems, which are substrates of ClpP proteases. We present a model for this anti-cell death effect of lambdaRexB through its action on the ClpP proteolytic subunit. We also propose that the lambdarex operon has an additional function to the well known phenomenon of exclusion of other phages; it can prevent the death of lysogenized cells under conditions of nutrient starvation. Thus, the rex operon may be considered as the "survival operon" of phage lambda.

Regulation of the Epstein-Barr viral immediate early BRLF1 promoter through a distal NF1 site

The immediate early BRLF1 and BZLF1 promoters of Epstein-Barr virus are crucial for triggering the replicative cycle of the virus. To better understand the cell type dependence of the lytic cycle we conducted an analysis of the BRLF1-promoter in the epithelial cell line HeLa and the lymphoid cell line IM9. To analyze promoter activities, transient transfections with 5'-deletions of the BRLF1-promoter in front of luciferase as reporter gene were conducted. Besides the already known cis-acting elements of the promoter close to the TATA-box, more distal elements were located and functionally tested. A nuclear factor 1 consensus site was found to act positively in HeLa cells, but did not in lymphoid IM9 cells. The NF1 site was shown to bind protein by electrophoretic mobility shift assays, antibody-supershifts and in vitro footprinting. Thus, a protein belonging to the nuclear factor 1 family of proteins was identified as additional cellular trans-acting factor for the BRLF1-promoter besides the already described factors Sp1, Zta and Zif268.

Analysis of the shut-off of ribosomal RNA promoters in Escherichia coli upon entering the stationary phase of growth

Most bacterial RNA consists of stable RNA which is composed of rRNA and tRNA. We have followed by primer extension analysis the level of ribosomal RNA synthesis along the growth phases of a cell culture. A sharp drop in rRNA synthesis was observed upon the transition from the exponential to the stationary phase of growth. Our results demonstrate that an effective shut-off of rRNA synthesis occurs also in the absence of ppGpp. Mutations in the host factors Fis and H-NS, which are known to regulate rrn P1 promoters, did not affect the shut-off process of ribosomal RNA promoters. We also tested the effect of RpoS, the sigma factor known to induce a number of genes in the stationary phase. It was shown that the host factors Fis, H-NS and RpoS do not play a major role in the regulation of the shut-off process of rRNA synthesis. The results presented demonstrate that the rate of rRNA synthesis provides a sensitive measure of the growth phase of the bacterial culture.

An Escherichia coli chromosomal "addiction module" regulated by guanosine [corrected] 3',5'-bispyrophosphate: a model for programmed bacterial cell death

"Addiction modules" consist of two genes. In most of them the product of one is long lived and toxic while the product of the second is short lived and antagonizes the toxic effect; so far, they have been described mainly in a number of prokaryotic extrachromosomal elements responsible for the postsegregational killing effect. Here we show that the chromosomal genes mazE and mazF, located in the Escherichia coli rel operon, have all of the properties required for an addiction module. Furthermore, the expression of mazEF is regulated by the cellular level of guanosine [corrected] 3',5'-bispyrophosphate, the product of the RelA protein under amino acid starvation. These properties suggest that the mazEF system may be responsible for programmed cell death in E. coli and thus may have a role in the physiology of starvation.

Conserved and divergent expression aspects of the Drosophila segmentation gene hunchback in the short germ band embryo of the flour beetle Tribolium

The segmentation gene hunchback (hb) plays a central role in determining the anterior-posterior pattern in the Drosophila embryo. We have cloned the homologue of hb from the flour beetle Tribolium and show that, on the basis of its expression pattern, most of its functions seem to be conserved between these two species. Like Drosophila, Tribolium has a maternal hb expression that appears to be under translational control by a factor at the posterior pole of the embryo. The maternal expression is followed by a zygotic expression in the region of the developing head and thoracic segments. During germ band extension, a posterior expression domain appears that is likely to be homologous to the posterior blastoderm expression of hb in Drosophila. These observations suggest that hb may have the same functions in early Drosophila and Tribolium development, despite the different types of embryogenesis in these two species (long versus short germ development). One differing aspect of hb expression in Tribolium concerns a structure that is not present in Drosophila, namely the serosa. An hb expression domain at the anterior pole precisely demarcates the border between the extraembryonic serosa and the embryonic field in the Tribolium embryo at an early stage, and hb protein remains expressed in the serosa cells until the end of embryogenesis.