Efficacy and quality of life for FOLFOX/bevacizumab +/- irinotecan in first-line metastatic colorectal cancer-final results of the AIO CHARTA trial

BACKGROUND

FOLFOXIRI plus bevacizumab has demonstrated benefits for metastatic colorectal cancer (mCRC) patients. However, challenges arise in its clinical implementation due to expected side effects and a lack of stratification criteria.

METHODS

The AIO "CHARTA" trial randomised mCRC patients into clinical Group 1 (potentially resectable), 2 (unresectable/risk of rapid progression), or 3 (asymptomatic). They received FOLFOX/bevacizumab +/- irinotecan. The primary endpoint was the 9-month progression-free survival rate (PFSR@9). Secondary endpoints included efficacy in stratified groups, QoL, PFS, OS, ORR, secondary resection rate, and toxicity.

RESULTS

The addition of irinotecan to FOLFOX/bevacizumab increased PFSR@9 from 56 to 67%, meeting the primary endpoint. The objective response rate was 61% vs. 69% (P = 0.21) and median PFS was 10.3 vs. 12 months (HR 0.83; P = 0.17). The PFS was (11.4 vs. 12.9 months; HR 0.83; P = 0.46) in potentially resectable patients, with a secondary resection rate of 37% vs. 51%. Moreover, Group 3 (asymptomatic) patients had a PFS of 11.1 vs. 16.1 months (HR 0.6; P = 0.14). The addition of irinotecan did not diminish QoL.

CONCLUSION

The CHARTA trial, along with other studies, confirms the efficacy and tolerability of FOLFOXIRI/bevacizumab as a first-line treatment for mCRC. Importantly, clinical stratification may lead to its implementation.

TRIAL REGISTRATION

The trial was registered as NCT01321957.

High-Dose Glucocorticoids for the Treatment of Sudden Hearing Loss

High-Dose Glucocorticoids for Sudden Hearing LossThis trial compared courses of high-dose intravenous prednisolone or high-dose oral dexamethasone versus standard-dose oral prednisone in adults with idiopathic sudden sensorineural hearing loss. At 30 days, systemic high-dose glucocorticoid therapy was not superior to a lower-dose regimen with respect to change in hearing threshold, and it was associated with a higher risk of side effects.

Liver-HERO: hepatorenal syndrome-acute kidney injury (HRS-AKI) treatment with transjugular intrahepatic portosystemic shunt in patients with cirrhosis-a randomized controlled trial

BACKGROUND

Patients with cirrhosis and ascites (and portal hypertension) are at risk of developing acute kidney injury (AKI). Although many etiologies exist, hepatorenal AKI (HRS-AKI) remains a frequent and difficult-to-treat cause, with a very high mortality when left untreated. The standard of care is the use of terlipressin and albumin. This can lead to reversal of AKI, which is associated to survival. Nevertheless, only approximately half of the patients achieve this reversal and even after reversal patients remains at risk for new episodes of HRS-AKI. TIPS is accepted for use in patients with variceal bleeding and refractory ascites, which leads to a reduction in portal pressure. Although preliminary data suggest it may be useful in HRS-AKI, its use in this setting is controversial and caution is recommended given the fact that HRS-AKI is associated to cardiac alterations and acute-on-chronic liver failure (ACLF) which represent relative contraindications for transjugular intrahepatic portosystemic shunt (TIPS). In the last decades, with the new definition of renal failure in patients with cirrhosis, patients are identified at an earlier stage. These patients are less sick and therefore more likely to not have contraindications for TIPS. We hypothesize that TIPS could be superior to the standard of care in patients with HRS-AKI.

METHODS

This study is a prospective, multicenter, open, 1:1-randomized, controlled parallel-group trial. The main end-point is to compare the 12-month liver transplant-free survival in patients assigned to TIPS compared to the standard of care (terlipressin and albumin). Secondary end-point include reversal of HRS-AKI, health-related Quality of Life (HrQoL), and incidence of further decompensation among others. Once patients are diagnosed with HRS-AKI, they will be randomized to TIPS or Standard of Care (SOC). TIPS should be placed within 72 h. Until TIPS placement, TIPS patients will be treated with terlipressin and albumin. Once TIPS is placed, terlipressin and albumin should be weaned off according to the attending physician.

DISCUSSION

If the trial were to show a survival advantage for patients who undergo TIPS placement, this could be incorporated in routine clinical practice in the management of patients with HRS-AKI.

TRIAL REGISTRATION

Clinicaltrials.gov NCT05346393 . Released to the public on 01 April 2022.

Ramucirumab in combination with dacarbazine in patients with progressive well-differentiated metastatic pancreatic neuroendocrine tumors (RamuNET): study protocol for a multicenter single-arm trial

BACKGROUND

Cytotoxic chemotherapy combinations and targeted agents represent established treatment concepts in advanced pancreatic neuroendocrine tumors (PNETs). However, response rates, side effects and outcome data strongly vary among these therapeutic approaches. Head-to-head comparisons between chemo- and molecular therapies are missing and secondary resistances frequently occur. The RamuNET trial aims to identify the effectiveness of dual treatment with DTIC and ramucirumab in progressive advanced PNET patients.

METHODS

The RamuNET study is an investigator-initiated multicenter prospective single-arm trial to evaluate the efficacy of ramucirumab in combination with dacarbazine (DTIC) over a period of at least 6 months. Patients with progressive well-differentiated and metastatic pancreatic neuroendocrine tumors are eligible. The study aims to include 45 patients over a period of 24 months with a minimum follow-up of 24 months. The primary endpoint is disease control after 6 months. Secondary endpoints include progression-free survival, biochemical response, overall survival, quality of life and toxicity. Based on the hypothesis that 80% of the patients can achieve a disease control after 6 months, the sample size calculation follows an exact binomial single-stage design. H0: p < =p0 = 60% versus H1: p > =p1 = 80%, alpha = 0.05, beta = 0.1.

DISCUSSION

This study investigates a new therapeutic approach using the combination of cytotoxic and targeted antiangiogenic therapy in advanced PNET. If positive, this trial will be the basis for a randomized two-arm study to investigate the combination of ramucirumab and DTIC against other established therapies in PNET.

TRIAL REGISTRATION

EudraCT: 2017-001207-68 . Date of registration: 2018.01.03.

Efficacy of Pazopanib With or Without Gemcitabine in Patients With Anthracycline- and/or Ifosfamide-Refractory Soft Tissue Sarcoma: Final Results of the PAPAGEMO Phase 2 Randomized Clinical Trial

Importance

Pazopanib and gemcitabine have shown good tolerability, albeit modest single-agent activity in pretreated soft tissue sarcoma. A combined regimen to improve outcomes is required.

Objective

To determine the efficacy of gemcitabine and pazopanib compared with pazopanib alone.

Design, Setting, and Participants

This multicenter, randomized phase 2 clinical trial was conducted in Germany from September 2011 to July 2014 and included patients with an Eastern Cooperative Oncology Group performance status score of 0 to 2, adequate organ function, measurable lesion, and progression after at least 1 prior treatment with anthracyclines and/or ifosfamide. Data analysis was performed during 2019 and 2020.

Interventions

Patients were randomized to pazopanib with gemcitabine (A) or without gemcitabine (B).

Main Outcomes and Measures

The primary end point was progression-free survival rate (PFSR) at 12 weeks; secondary end points included toxicity, quality of life, overall survival, and response rates.

Results

A total of 90 patients were randomized, and 86 eligible patients (43 women [50%]) were evaluable, with a median age of 57 (range, 22-84) years and Eastern Cooperative Oncology Group performance status score of 0/1 in 77 participants (90%). The predominant histological subtypes were leiomyosarcoma (22 [26%]) and liposarcoma (16 [19%]). After a median follow-up of 12.4 (range, 1-48) months, the primary end point was met, with a PFSR at 12 weeks of 74% (A) vs 47% (B) (hazard ratio [HR], 1.60; 90% CI, 1.15-2.23; P = .01). In the combination arm, PFSR was significantly longer, with a median of 5.6 vs 2.0 months (HR, 0.58; 95% CI, 0.36-0.92; P = .02) compared with single-agent pazopanib, whereas overall survival was similar, with 13.1 vs 11.2 months (HR, 0.98; 95% CI, 0.60-1.58; P = .83). The objective response rate was overall low, with 11% (A) vs 5% (B) (P = .10). The toxicity of the combination of pazopanib and gemcitabine was increased, but it was manageable and mainly hematological.

Conclusions and Relevance

This phase 2 randomized clinical trial of patients with soft tissue sarcoma found that the addition of gemcitabine to pazopanib was tolerable, and PFSR at 12 weeks was significantly higher compared with pazopanib alone. These results suggest clinical activity of the combination, but they should be confirmed in a phase 3 trial in a more homogeneous population (eg, leiomyosarcoma).

Trial Registration

German Clinical Trials Identifier: DRKS00003139.

Impact of FOLFOXIRI and bevacizumab (bev) compared to FOLFOX and bev on health related quality of life (HRQOL) in patients with metastatic colorectal cancer (MCRC): Analysis of the CHARTA-AIO 0209 trial

3544

Background: FOLFOXIRI/bev is a highly efficacious first line regimen in MCRC. Despite higher rates of neutropenia, diarrhea and stomatitis, FOLFOXIRI/bev is tolerable and feasible in MCRC patients. To date nothing is known about the impact of this regimen on HRQOL. Methods: 250 patients were randomized to FOLFOX/bev (arm A) or FOLFOXIRI/bev (arm B). HRQOL were assessed at baseline, every 8 weeks during induction treatment (6 months) and every 12 weeks during maintenance treatment, using the EORTC QLQ-C30, QLQ-CR29 and QLQ-CIPN20. The mean values of every score were calculated as the average of week 8, 16 and 24 assessment. Test concerning mean values were performed as t-test, with global type I error set at 0.05. HRQOL deterioration and improvement rates were analyzed and compared between treatment groups using chi² tests. Results: For HRQOL analysis, 237 patients were eligible (arm A: 118; arm B: 119). Compliance rate with the HRQOL questionnaires was 95.4% at baseline, 72.6% at week 8, 59.5 % at week 16 and 43.5% at week 24. Whereas mean global quality of life score (GHS/QOL) was similar between arm A and B (59.8 vs. 58.8; p = 0.726), mean scores for nausea/vomiting (9.4 vs. 16.0; p = 0.015) and diarrhea (23.7 vs. 32.1; p = 0.051) significantly or borderline significantly favored arm A during induction period. Furthermore, at week 8 scores of nausea/vomiting (9.2 versus 17.3, p = 0.006) appetite loss (19.5 vs. 29.4; p = 0.035) and financial problems (18.3 vs. 29.5; p = 0.021) and at the end of treatment physical functioning (75.0 vs. 65.8; p = 0.048) were significantly better for arm A compared to arm B. No significant differences were observed in the remaining EORTC scores. The rates of deterioration and improvement between baseline and week 8 of at least 10 points in the EORTC scores were similar (e.g. deterioration-rate GHS/QOL score 21.5% vs. 26.5% for arm A vs. B; p = 0.461). Conclusions: Although no remarkable detriment in HRQOL was noted, the better efficacy of FOLFOXIRI/bev compared to FOLFOX/bev is associated with a decrease in mainly gastrointestinal QOL scores. Further subgroup-analyses will be presented at the meeting. Clinical trial information: NCT01321957.

“CHARTA”: FOLFOX/Bevacizumab vs. FOLFOXIRI/Bevacizumab in advanced colorectal cancer—Final results, prognostic and potentially predictive factors from the randomized Phase II trial of the AIO

3533

Background: FOLFOXIRI/Bevacizumab (Bev) is superior to FOLFIRI/Bev in the TRIBE trial (F Loupakis, NEJM 2014). The CHARTA trial was developed parallel to TRIBE with the same 4-drug-protocol but vs. FOLFOX/B ev as control arm. Methods: From 7/11 to 12/14 250 patients were randomized, including ECOG 0-2, ≥ 1 measurable lesion > 1cm, stratified by ESMO-Group 1,2,3 (HJ Schmoll, Ann Oncol 2012). Induction: 6 months, maintenance Capecitabine+Bev until progression or max.12 months, at P reinduction by investigators decision. 25% dose reduction was allowed in cycle 1 + 2 on the investigator’s discretion. Primary EP: significant improvement of PFS-rate @ 9 months (p<0.1, 2-sided Fisher’s-exact test); secondary EP: RR, PFS, OS, toxicity. Results: 241 pts. (1 not elig., 8 prot. violation) are evaluable after a follow up of 31.4 (0.1-51) months. m/f: 65%/35%, age 61y (21-82), ECOG 0-1/2: 96%/4%. The Primary Endpoint was met: PFS @ 9 months 56% vs. 68%, p= 0.086. PFS was improved: 9.8 vs. 12.0 months, HR 0.7 (ns.), identical to TRIBE with 9.7 vs. 12.1 months. Response rate (A/B): CR: 5%/5%, CR/PR 60%/70%, SD 25%/21%, PD 14%/9%. Final OS will be available at the meeting. Toxicity was low to moderate without major differences except ° ¾ diarrhea (12%/16%) and neutrophils (14%/20%). Clinical/molecular prognostic or predictive factors are equally distributed (stratification by ESMO groups) (see table). There are major, but mostly not significant differences in RR/ PFS in most subgroups, however, not strong enough to safely identify patients with high potential to benefit from the 4-drug combination. Therefore, a multivariate analysis to model a common prognostic and predictive risk score is ongoing and will be presented at the meeting. Conclusion: “CHARTA” supports the superiority of FOLFOXIRI/Bev. A combined prognostic and predictive classification is required to better select those patients with most potential benefit from the 4-drug combination. Clinical trial information: NCT01321957. [Table: see text]

Prophylactic nimodipine treatment and improvement in hearing outcome after vestibular schwannoma surgery: a combined analysis of a randomized, multicenter, Phase III trial and its pilot study

OBJECTIVE In clinical routines, neuroprotective strategies in neurosurgical interventions are still missing. A pilot study (n = 30) and an analogously performed Phase III trial (n = 112) pointed to a beneficial effect of prophylactic nimodipine and hydroxyethyl starch (HES) in vestibular schwannoma (VS) surgery. Considering the small sample size, the data from both studies were pooled. METHODS The patients in both investigator-initiated studies were assigned to 2 groups. The treatment group (n = 70) received parenteral nimodipine (1-2 mg/hour) and HES (hematocrit 30%-35%) from the day before surgery until the 7th postoperative day. The control group (n = 72) was not treated prophylactically. Facial and cochlear nerve functions were documented preoperatively, during the inpatient care, and 1 year after surgery. RESULTS Pooled raw data were analyzed retrospectively. Intent-to-treat analysis revealed a significantly lower risk for hearing loss (Class D) 12 months after surgery in the treatment group compared with the control group (OR 0.46, 95% CI 0.22-0.97; p = 0.04). After exclusion of patients with preoperative Class D hearing, this effect was more pronounced (OR 0.38, 95% CI 0.17-0.83; p = 0.016). Logistic regression analysis adjusted for tumor size showed a 4 times lower risk for hearing loss in the treatment group compared with the control group (OR 0.25, 95% CI 0.09-0.63; p = 0.003). Facial nerve function was not significantly improved with treatment. Apart from dose-dependent hypotension (p < 0.001), the study medication was well tolerated. CONCLUSIONS Prophylactic nimodipine is safe and may be recommended in VS surgery to preserve hearing. Prophylactic neuroprotective treatment in surgeries in which nerves are at risk seems to be a novel and promising concept. Clinical trial registration no.: DRKS 00000328 ( https://drks-neu.uniklinik-freiburg.de/drks_web/ ).

CHARTA: FOLFOX+bevacizumab +/- irinotecan in advanced colorectal cancer (CRC)—Final results of the randomized phase II trial of the AIO (KRK 0209)

658

Background: The 4-drug-regimen FOLFOXIRI+Bevacizumab (Bev) was superior to FOLFIRI+Bev (TRIBE F.Loupakis, NEJM 2014). CHARTA investigates the same 4-drug-regimen vs. FOLFOX+Bev. Methods: 250 patients were randomized from 7/11 to 12/14 to standard FOLFOX+Bev (A) vs. FOLFOXIRI+Bev (B), with dose/schedule as in TRIBE, 25% dose reduction in cycle 1 + 2, if necessary. Incl.criteria: ECOG 0-2, ≥ 1 measurable lesion > 1cm; stratified by ESMO-Group 1, 2, 3 (HJ Schmoll et. al., Ann Oncol 2012). Induction: 6 months, maintenance Capecitabine+Bev until progression or max. of 12 months, with reinduction by individual decision. Primary EP: significant improvement of PFS-rate at 9 months (p<0.1, 2-sided Fisher’s-exact test); secondary EP: RR- rate, PFS, OS, sec. resection. Results: Evaluable 241 pts. (1 not elig., 8 prot. violation); m/f: 65%/35%, age 61 yrs. (21-82), left/right: left A: 51, 5%, B: 48, 5%; right A: 45%, B: 55%; ECOG 0-1/2: 96% / 4%, ESMO-group 1/2/3: 29%/ 55%/ 16%. Primary endpoint was met: significantly improved PFS at 9 months 56% vs. 68% (p= 0,086). Preliminary PFS 9,76 vs. 12,0 months (HR 0.77, p=0.61), identical to TRIBE: 9.7 vs. 12.1. Response (A/B): CR: 5/5%, CR/PR 60/70%, SD 25/21%, PD 14/9%; sec. resection: 21/23%. Subgroup - analyses did not show significant differences, except CR / PR left/right (A/B): left 59/68%, right 63/73%; PFS (months) left 10.4/12 (HR 0.69, p=0.03), right: 8.2 /10.7); non-significant improvement in ESMO-group 3 (HR 0.51), RAS-wt (HR 0.67), Koehne-Score High risk HR 0.58; ECOG 1: HR 0.69. QL-Global- Health-Score: slightly worse in A, vs. improved in B. Dose-intensity <70%/ 70-90%/ >90% (A/B): 39/37%/ 18/26%/ 41%/36%; initial dose-reduction 17% of pts. Toxicity: low to moderate without major differences between A &B, except grade ¾ diarrhea 12/16%, neutrophils 14/20%, GI 12/20%. Conclusions: The 4-drug-regimen has superior activity with the same outcome as TRIBE and is well tolerated, without a negative effect of initial dose-reduction, and an improvement of global QoL-Score. Final PFS, OS data and detailed subgroup/multivariate analysis, including Quality of life data, will be presented. Clinical trial information: NCT01321957.

[Adherence to Phase III Cardiac Rehabilitation Programs: A Prospective, Randomized Comparison between a Conventionally Conducted Program and a Tai Chi-Based Program]

INTRODUCTION

In patients with cardiac diseases, lifestyle changes such as an increase in physical activity are recommended to prevent further cardiac events. In Germany this is possible by attending outpatient heart groups. A problem inherent in these programs is the lack of adherence since more than two thirds of patients stop attending cardiac rehabilitation programs after six months. An alternative to the conventional implementation of heart groups is Tai Chi, which was found to improve adherence to cardiac rehabilitation programs in international studies.

METHODS

Patients were randomly assigned to a conventional heart group or a heart group with Tai Chi exercises. At the beginning of the study, a medical history was taken and physical and instrumental tests were carried out, including an assessment of anxiety/depression (HADS questionnaire) and physical well-being (SD-12). Follow-up tests were performed every three months.

RESULTS

Patients were 62.6 ± 8.5 years old, the mean BMI was 28.6 ± 62 kg/m(2), and the proportion of women was 29.8 %. The groups were different in terms of age (conventional heart group: 65.0 ± 7.5; Tai Chi group: 59.9 ± 8.9 years). Therefore, age-adjusted analyses were performed in addition to the planned analyses. Regarding the primary endpoint of the study, there was no difference between the groups. After twelve months, 50 % of subjects were active in the Tai Chi group and 48 % in the conventional heart group (odds ratio 0.92, p = 0.891). After adjustment for age by logistic regression, the odds ratio was 0.47 (p = 0.285). Furthermore, both the participation period in weeks (Tai Chi group: 43.3 ± 26.0; conventional group: 45.5 ± 24.2, p = 0.766) and the participation rate (Tai Chi group: 66.8 ± 19.2 % Tai Chi, conventional group: 76.3 ± 16.5 %, p = 0.074) did not differ between the two groups. A further analysis showed a non-significant trend for improvement of anxiety, depression and physical well-being in the Tai Chi group compared with the conventional group.

CONCLUSION

The insight gained in international studies regarding a better adherence to Tai Chi-guided prevention programs was not transferable to heart group participants from Germany. However, there was a trend regarding a better mental condition in the Tai Chi group.

Prophylactic nimodipine treatment for cochlear and facial nerve preservation after vestibular schwannoma surgery: a randomized multicenter Phase III trial

OBJECTIVE

A pilot study of prophylactic nimodipine and hydroxyethyl starch treatment showed a beneficial effect on facial and cochlear nerve preservation following vestibular schwannoma (VS) surgery. A prospective Phase III trial was undertaken to confirm these results.

METHODS

An open-label, 2-arm, randomized parallel group and multicenter Phase III trial with blinded expert review was performed and included 112 patients who underwent VS surgery between January 2010 and February 2013 at 7 departments of neurosurgery to investigate the efficacy and safety of the prophylaxis. The surgery was performed after the patients were randomly assigned to one of 2 groups using online randomization. The treatment group (n = 56) received parenteral nimodipine (1-2 mg/hr) and hydroxyethyl starch (hematocrit 30%-35%) from the day before surgery until the 7th postoperative day. The control group (n = 56) was not treated prophylactically.

RESULTS

Intent-to-treat analysis showed no statistically significant effects of the treatment on either preservation of facial nerve function (35 [67.3%] of 52 [treatment group] compared with 34 [72.3%] of 47 [control group]) (p = 0.745) or hearing preservation (11 [23.4%] of 47 [treatment group] compared with 15 [31.2%] of 48 [control group]) (p = 0.530) 12 months after surgery. Since tumor sizes were significantly larger in the treatment group than in the control group, logistic regression analysis was required. The risk for deterioration of facial nerve function was adjusted nearly the same in both groups (OR 1.07 [95% CI 0.34-3.43], p = 0.91). In contrast, the risk for postoperative hearing loss was adjusted 2 times lower in the treatment group compared with the control group (OR 0.49 [95% CI 0.18-1.30], p = 0.15). Apart from dose-dependent hypotension (p < 0.001), no clinically relevant adverse reactions were observed.

CONCLUSIONS

There were no statistically significant effects of the treatment. Despite the width of the confidence intervals, the odds ratios may suggest but do not prove a clinically relevant effect of the safe study medication on the preservation of cochlear nerve function after VS surgery. Further study is needed before prophylactic nimodipine can be recommended in VS surgery.

Efficiency and safety of inhalative sedation with sevoflurane in comparison to an intravenous sedation concept with propofol in intensive care patients: study protocol for a randomized controlled trial

Background

State of the art sedation concepts on intensive care units (ICU) favor propofol for a time period of up to 72 h and midazolam for long-term sedation. However, intravenous sedation is associated with complications such as development of tolerance, insufficient sedation quality, gastrointestinal paralysis, and withdrawal symptoms including cognitive deficits. Therefore, we aimed to investigate whether sevoflurane as a volatile anesthetic technically implemented by the anesthetic-conserving device (ACD) may provide advantages regarding ‘weaning time’, efficiency, and patient’s safety when compared to standard intravenous sedation employing propofol.

Method/Design

This currently ongoing trial is designed as a two-armed, monocentric, randomized prospective phase II study including intubated intensive care patients with an expected necessity for sedation exceeding 48 h. Patients are randomly assigned to either receive intravenous sedation with propofol or sevoflurane employing the ACD. Primary endpoint is the comparison of the ‘weaning time’ defined as the time required from discontinuation of the sedating agent until sufficient spontaneous breathing occurs. Moreover, sedation depth evaluated by Richmond Agitation Sedation Scale and parameters of patient’s safety (that is, vital signs, laboratory monitoring of organ function) as well as the duration of mechanical ventilation and overall stay on the ICU are analyzed and compared. An intention-to-treat analysis will be carried out with all patients for whom it will be possible to define a wake-up time. In addition, a per-protocol analysis is envisaged. Completion of patient recruitment is expected by the end of 2012.

Discussion

This clinical study is designed to evaluate the impact of sevoflurane during long-term sedation of critically ill patients on ‘weaning time’, efficiency, and patient’s safety compared to the standard intravenous sedation concept employing propofol.

Trial registration

EudraCT2007-006087-30; ISCRTN90609144

Regulatory interaction of the Galpha protein with phospholipase A2 in the plasma membrane of Eschscholzia californica

Plant heterotrimeric G-proteins are involved in a variety of signaling pathways, though only one alpha and a few betagamma isoforms of their subunits exist. In isolated plasma membranes of California poppy (Eschscholzia californica), the plant-specific Galpha subunit was isolated and identified immunologically and by homology of the cloned gene with that of several plants. In the same membrane, phospholipase A(2) (PLA(2)) was activated by yeast elicitor only if GTPgammaS (an activator of Galpha) was present. From the cholate-solubilized membrane proteins, PLA(2) was co-precipitated together with Galpha by a polyclonal antiserum raised against the recombinant Galpha. In this immunoprecipitate and in the plasma membrane (but not in the Galpha-free supernatant) PLA(2) was stimulated by GTPgammaS. Plasma membranes and immunoprecipitates obtained from antisense transformants with a low Galpha content allowed no such stimulation. An antiserum raised against the C-terminus (which in animal Galphas is located near the target coupling site) precipitated Galpha without any PLA(2) activity. Using non-denaturing PAGE, complexes of solubilized plasma membrane proteins were visualized that contained Galpha plus PLA(2) activity and dissociated at pH 9.5. At this pH, PLA(2) was no longer stimulated by GTPgammaS. It is concluded that a distinct fraction of the plasma membrane-bound PLA(2) exists in a detergent-resistant complex with Galpha that can be dissociated at pH 9.5. This complex allows the Galpha-mediated activation of PLA(2).

Intracellular pH signals in the induction of secondary pathways--the case of Eschscholzia californica

Transient peaks of the cytoplasmic pH are essential elements in a number of signal cascades that activate environmental responses or developmental processes in plant cells but little is known about the mechanisms of their generation. In many plant cells, elicitation of the hypersensitive response is preceded by a perturbation of the ionic balance at the plasma membrane including the inhibition of the proton pump and the influx of H+ from the apoplast. A basically different mechanism of cytoplasmic acidification that is fed by vacuolar protons has been discovered in cell suspensions of the California Poppy (Eschscholzia californica). These cells react to a yeast glycoprotein elicitor with the overproduction of benzophenanthridine alkaloids. Low elicitor concentrations trigger the biosynthesis of these phytoalexins without invoking elements of the hypersensitive response. Accumulated data support the existence of a signal path that includes the following steps: Links between the above events that connect them within a distinct signal path are substantiated by the phenotypes of transformed cell lines that either display lowered Galpha levels due to antisense transformation or express Galpha-binding antibodies in the cytoplasm. All of these cell lines lack the elicitor-activation of PLA2 and of vacuolar proton fluxes and show an impaired phytoalexin response to low elicitor concentrations. High elicitor concentrations trigger alkaloid biosynthesis via an increase of jasmonate at a pH-independent signal path.

Uric acid is a genuine metabolite of Penicillium cyclopium and stimulates the expression of alkaloid biosynthesis in this fungus

On searching for endogenous, low-molecular-weight effectors of benzodiazepine alkaloid biosynthesis in Penicillium cyclopium uric acid was isolated from ethanolic or autoclaved mycelial extracts of this fungus. The isolation was based on a three-step high-pressure liquid chromatography procedure guided by a microplate bioassay, and uric acid was identified by mass spectrometry and the uricase reaction. Conidiospore suspensions that were treated with this compound during the early phase of outgrowth developed emerged cultures with an enhanced rate of alkaloid production. Uric acid treatment did not increase the in vitro measurable activity of the rate-limiting biosynthetic enzyme, cyclopeptine synthetase. However, these cultures displayed a reduced rate of uptake of the alkaloid precursor L-phenylalanine into the vacuoles of the hyphal cells as assayed in situ. It is suggested that the depressed capacity of vacuolar uptake caused by the contact of outgrowing spores with uric acid liberated from hyphal cells results in an enhanced availability of the precursor L-phenylalanine in the cytoplasm and thus accounts at least in part for the increase in alkaloid production.

Selective regulatory effects of purine and pyrimidine nucleotides on vacuolar transport of amino acids

The release of amino acids from their vacuolar store was studied in situ, i.e. in cells with selectively permeabilized plasma membrane and functionally intact vacuoles. As we previously described [Roos et al., J. Biol. Chem. 272 (1997) 15849-15855], this transport process is regulated by extravacuolar adenylates at their physiological concentrations. We now show, using our test object Penicillium cyclopium, that not only purine but also pyrimidine nucleotides are involved in the control of efflux of vacuolar phenylalanine. At 0.1 mM adenosine or guanosine phosphates inhibit, whereas cytidine or uridine phosphates stimulate the rate of efflux. At 1 mM the same nucleotides have no measurable impact on efflux but abolish the effects of other nucleotides present at 0.1 mM. This argues for at least two interacting binding sites with different nucleotide affinities. The minimum structural requirement for any of the observed effects is a non-cyclic ribonucleoside monophosphate. In intact cells, cytosolic concentrations of ATP (representing purine nucleotides) and CTP (representing pyrimidine nucleotides) are 1-2 mM and 0.05-0.2 mM, respectively. ATP is therefore assumed to dominate transport control and allow optimum efflux (and uptake) rates. Short-time starvation of carbon and nitrogen adjusts CTP and ATP at levels that cause declining efflux rates. During prolonged starvation both nucleotides fall below their transport-controlling concentrations and thus allow increasing rates of efflux from the still maintained vacuolar pool. Hence, efflux control under nutrient limitation includes an interplay of purine and pyrimidine nucleotides which precisely regulates the release of vacuolar amino acids and enables flexible adjustment to either amino acid saving or cell survival.

A redox-dependent, G-protein-coupled phospholipase A of the plasma membrane is involved in the elicitation of alkaloid biosynthesis in Eschscholtzia californica

In cultured cells of California poppy formation of benzophenanthridine alkaloids can be triggered by a yeast elicitor preparation independently of the hypersensitive reaction. A plasma membrane (PM) bound phospholipase A (PLA) is likely to play a role in the signalling process: PLA activity was detectable in individual cells, cell suspensions and PM vesicles with the fluorogenic phospholipid bis-BODIPY FL C11-PC and was sensitive to known inhibitors of PLA2. In microscopic assays, enzyme activity increased after elicitor contact of cells that were pretreated with non-saturating concentrations of PLA2 inhibitors. In PM vesicles a PLA2-like protein as well as G alpha- and G beta-proteins were detected immunologically. Anti-G alpha or anti-G beta antisera or mastoparan stimulated PLA activity thus indicating a G-protein-controlled enzyme. Elicitation of alkaloid production was sensitive to aristolochic acid and enhanced by PLA2 products such as lysophosphatidylcholine and linolenic acid. Pretreatment of the cells with the artificial electron acceptors hexabromoiridate(V) or ferricyanide(III) reversibly abolished the effect of subsequent elicitation and reduced the activity of PLA both in intact cells and in PM vesicles. It appears, therefore, that PLA2 is a point of interference of redox control with the signal path.

Differences in cytotoxicity of native and engineered RIPs can be used to assess their ability to reach the cytoplasm

Ricin is a heterodimeric cytotoxin composed of RTB, a galactose binding lectin, and RTA, an enzymatic N-glycosidase. The toxin is endocytosed, and after intracellular routing, RTA is translocated to the cytoplasm where it inactivates ribosomes resulting in a loss of host cell protein synthesis and cell death. We show for the first time that the cytotoxicity against cultured T cells by several RTA mutants is directly proportional to the enzyme activity of RTA, suggesting this is a reliable system to measure translocation effects. Large discrepancies between cytotoxicity and enzyme action for a given pair of toxins are therefore attributable to differences in cell binding, uptake, or membrane translocation. Fluid phase uptake and cytotoxicity of isolated RTA are essentially identical to that of the single chain toxin PAP. This important finding suggests that RTA, and the A chain of class 2 RIPs in general, has not evolved special translocation signals to complement the increased target cell binding facilitated by RTB. Experiments with the lectin RCA and with ebulin suggest those toxins have diminished cytotoxicity probably mediated by comparative deficiencies in B chain binding. Addition of a KDEL sequence to RTA increases fluid phase uptake, consistent with the notion that transport to the ER is important for cytotoxicity. Fusion of MBP or GST to the amino terminus of RTA has little effect on enzyme action or cytotoxicity. This result is not altered by protease inhibitors, suggesting the fusion proteins are probably not cleaved prior to translocation of the toxic A chain and implying that the toxins can carry large passenger proteins into the cytoplasm, an observation with interesting potential for analytical and therapeutic chemistry.

Dynamic compartmentation of vacuolar amino acids in Penicillium cyclopium. Cytosolic adenylates act as a control signal for efflux into the cytosol

The regulation of amino acid transport from the vacuolar reservoir into the cytoplasm has been studied in hyphal cells of Penicillium cyclopium. To avoid artifacts caused by the isolation of vacuoles, efflux was examined "in situ," i.e. in cells whose plasma membranes were permeabilized for micromolecules by a treatment with nystatin. The ATP-dependent proton gradient and amino acid transport activities at the vacuolar membrane remained intact under these conditions. Accumulation of amino acids in the vacuole proved to be the result of a dynamic equilibrium of active, ATP-dependent uptake and energy-independent efflux. The latter was strongly accelerated after the vacuolar amino acid content had surpassed a threshold level. Efflux of vacuolar amino acids was specifically controlled by extravacuolar adenylates: ATP, 5'-adenylyl imidodiphosphate (an ATPase-resistant ATP-analogue), ADP, or AMP caused a strong inhibition in the concentration range around 200 micromol/liter, whereas both lower and higher concentrations allowed significant efflux rates. Estimates of the cytosolic adenylates (which consisted mainly of ATP) were close to 2 mmol/liter in glucose-metabolizing cells, which concentration allowed maximum rates of both vacuolar uptake and efflux. During 24 h of carbon and nitrogen starvation, the adenylate level decreased toward the efflux-inhibiting region around 200 micromol/liter, whereas 3-4 d of carbon and nitrogen starvation caused a further decline of the adenylate content, leading again to efflux-permitting concentrations. Thus, the cytosolic adenylate pool appears to effectively control the availability of vacuolar amino acids for the cellular metabolism.

Production and immobilization of a proteinase-reduced cyclodextrin glycosyltransferase preparation

Cyclodextrin glycosyltransferase (CGTase) was produced by a 3-day cultivation of Bacillus macerans growing in a natural medium containing grated-potatoes. Besides CGTase the culture supernatant contained a mixture of serine proteinases with a predominant subtilisin-like activity. By fractionated precipitation with ammonium sulphate the CGTase (molecular mass approximately 70 kDa) was concentrated and largely separated from the proteinases (molecular mass approximately 28 kDa). Among the various immobilization methods and carrier materials tested the enriched CGTase was covalently bound preferably onto porous glass beads using glutardialdehyde as cross-linker. The discontinuous conversion of soluble starch into beta-cyclodextrin was carried out with native as well as immobilized CGTase over 24 h. The batch re-usability of the fixed enzyme proved to be at least 20 times with a residual CGTase activity of 65%.