Developing a rapid and highly efficient cowpea regeneration, transformation and genome editing system using embryonic axis explants

Cowpea (Vigna unguiculata (L.) Walp.) is one of the most important legume crops planted worldwide, but despite decades of effort, cowpea transformation is still challenging due to inefficient Agrobacterium-mediated transfer DNA delivery, transgenic selection and in vitro shoot regeneration. Here, we report a highly efficient transformation system using embryonic axis explants isolated from imbibed mature seeds. We found that removal of the shoot apical meristem from the explants stimulated direct multiple shoot organogenesis from the cotyledonary node tissue. The application of a previously reported ternary transformation vector system provided efficient Agrobacterium-mediated gene delivery, while the utilization of spcN as selectable marker enabled more robust transgenic selection, plant recovery and transgenic plant generation without escapes and chimera formation. Transgenic cowpea plantlets developed exclusively from the cotyledonary nodes at frequencies of 4% to 37% across a wide range of cowpea genotypes. CRISPR/Cas-mediated gene editing was successfully demonstrated. The transformation principles established here could also be applied to other legumes to increase transformation efficiencies.

Developing a rapid and highly efficient cowpea regeneration, transformation and genome editing system using embryonic axis explants

Cowpea (Vigna unguiculata (L.) Walp.) is one of the most important legume crops planted worldwide, but despite decades of effort, cowpea transformation is still challenging due to inefficient Agrobacterium-mediated transfer DNA delivery, transgenic selection and in vitro shoot regeneration. Here, we report a highly efficient transformation system using embryonic axis explants isolated from imbibed mature seeds. We found that removal of the shoot apical meristem from the explants stimulated direct multiple shoot organogenesis from the cotyledonary node tissue. The application of a previously reported ternary transformation vector system provided efficient Agrobacterium-mediated gene delivery, while the utilization of spcN as selectable marker enabled more robust transgenic selection, plant recovery and transgenic plant generation without escapes and chimera formation. Transgenic cowpea plantlets developed exclusively from the cotyledonary nodes at frequencies of 4% to 37% across a wide range of cowpea genotypes. CRISPR/Cas-mediated gene editing was successfully demonstrated. The transformation principles established here could also be applied to other legumes to increase transformation efficiencies.

Phase III trial of casopitant, a novel neurokinin-1 receptor antagonist, for the prevention of nausea and vomiting in patients receiving moderately emetogenic chemotherapy

PURPOSE

The purpose of this phase III trial was to evaluate the efficacy and safety of regimens containing casopitant, a novel neurokinin-1 receptor antagonist, for the prevention of chemotherapy-induced nausea and vomiting during the first cycle in patients receiving moderately emetogenic chemotherapy (MEC).

PATIENTS AND METHODS

Predominantly female patients (98%) diagnosed with breast cancer (96%) who were chemotherapy-naïve and scheduled to receive an anthracycline and cyclophosphamide (AC) -based regimen were enrolled onto this multinational, randomized, double-blind, parallel-group, placebo-controlled clinical trial. All patients received dexamethasone 8 mg intravenously (IV) on day 1 and oral ondansetron 8 mg twice daily on days 1 to 3. Patients were randomly assigned to a control arm (placebo), a single oral dose casopitant arm (150 mg orally [PO] on day 1), a 3-day oral casopitant arm (150 mg PO on day 1 plus 50 mg PO on days 2 to 3), or a 3-day IV/oral casopitant arm (90 mg IV on day 1 plus 50 mg PO on days 2 to 3). The primary end point was the proportion of patients achieving complete response (no vomiting/retching or rescue medications) in the first 120 hours after the initiation of MEC.

RESULTS

A significantly greater proportion of patients in the single-dose oral casopitant arm, 3-day oral casopitant arm, and 3-day IV/oral casopitant arm achieved complete response (73%, 73%, and 74%, respectively) versus control (59%; P < .0001). The study did not demonstrate a reduced proportion of patients with nausea or significant nausea in those receiving casopitant. Adverse events were balanced among study arms.

CONCLUSION

All casopitant regimens studied were more effective than the control regimen. Casopitant was generally well tolerated.

Treatment of advanced chemo-refractory epithelial ovarian cancer with aromatase inhibitor

e16561

Background: In advanced epithelial ovarian cancer non-steroidal antiestrogens yields clinical responses in a significant number of patients. This raises the possibility of therapeutic effectiveness of aromatase inhibitors in epithelial ovarian cancer in post menopausal women. Therefore this study was carried out to document the effectiveness of an aromatase inhibitor, in advanced epithelial ovarian cancer patients with unknown hormone receptor status. Methods: From January 2006 to April 2007, a total of 38 patients were enrolled. Patients with histopathologically confirmed advanced epithelial ovarian cancer were included. Other eligibility requirements were: postmenopausal women, failure of third-line chemotherapy, age between 50–70 years, bidimensionally measurable disease, and CA-125 of more than 100 u/mL. An adequate hematologic, hepatic, and renal profile, and ECOG performance of 0–2 was required. Tablet letrozole 2.5 mg orally once daily was given for 03 months. CA-125 and Miller criteria were used for response evaluation. Results: No patient showed the evidence of complete or partial clinical response. Four patients had stable disease for 8 weeks. All patients showed progressive disease on week 12. Conclusions: In this small series no evidence of effectiveness of aromatase inhibitor letrozole in chemo refractory epithelial ovarian cancer is documented in patients with unknown hormone receptor status. It is, therefore, recommended that further study should only be carried out in the selected patient population with documented positive ER/PR hormone receptors.

No significant financial relationships to disclose.

A phase II feasibility study of cytarabine and idarubicin combination in relapsed or refractory adult acute lymphoblastic leukemia

e18002

Background: Most patients with adult ALL eventually relapse. Salvage regimens in these patients and in patients with primary refractory disease are generally based on cytarabine in combination with other agents. Exact merit of each combination remains undefined as these continue to be tested in non randomized trials. This study was conducted with the objectives to find out the efficacy and toxicity of cytarabine and idarubicin combination. Methods: From December 2006 to March 2008, 30 patients were enrolled in this prospective, nonrandomized single institution phase II feasibility study. It was empirically decided that the study will only be considered feasible if more then ten patients achieve a complete remission. Patients who relapsed during maintenance therapy or were refractory and were at least 16-years-old were considered eligible provided they have received at least vincristine and prednisone as induction. No prior cytarabine was allowed. Cytarabine 100 mg/m2 continuous infusion for seven days along with idarubicin 12 mg/m2 day 1 to 3, IV bolus was given. Bone marrow examination was done 15 days after the completion of chemotherapy. Results: All thirty patients completed planned treatment. Five patients died of infection during treatment. Eleven patients achieved complete remission. All patients relapsed within eight months. Conclusions: The regimen of cytrarabine and idarubicin is feasible and sufficiently effective in relapsed or refractory adult ALL with manageable toxicity.

No significant financial relationships to disclose.

Gemcitabine and concurrent radiation as a salvage treatment of chest wall recurrence in breast cancer

11027

Background: Chest wall recurrences are seen despite postoperative chemotherapy and radiotherapy. For patients with unresectable lesions who have previously received radiotherapy no standard treatment is available. We devised a protocol of low dose gemcitabine as radiosensitizer concurrent with low dose of radiation and conducted this study with the objectives to document the efficacy and toxicity of this protocol. Methods: From January 2003 to August 2005, 48 patients were included in this study. A histopthological or cytological evidence of chest wall recurrence was required. Females between 18–70 years, with previous modified radical mastectomy, post operative radiation and adjuvant chemotherapy were included. Patients with metastatic disease were excluded. Written informed consent was obtained. A dose of 150 mg / m2 of gemcitabine in 200 ml of normal saline was infused in 2 hour on day 1, 8, 15 and 22 of radiation. Radiation was delivered 2 hours after the completion of infusion. Conventional fractionation was used to deliver a total dose of 36 Gy given in 3.5 weeks. RECIST and RTOG criteria were used. Results: Twenty recurrences were related to the scar, 10 to the involved internal mammary lymph node region invading sternum and ribs and 18 were associated with the soft tissue masses outside the scar area. All patients were evaluable for response and toxicity. Complete response was seen in 6 (12.5 %) patients, (95 % CI, 13.87_37.16), partial response was seen in 30 (62.5 %) (95 % CI, 44.92 -71.40) with an over all response rate of 75 % (95 % CI, 70.57—91.40) Stable disease was seen in 9 (18.8 %) patients and disease progression in 3 (6.3 %) patients. Grade I skin reaction was seen in 15 (31.2 % ) patients grade II in 11 ( 22.9 % ) and grade III in 3 ( 6.3 % ) patients. No systemic toxicity was seen. Conclusions: Low dose gemcitabine and concurrent radiotherapy is a reasonable salvage treatment in chest wall recurrence in breast cancer patients who have previously received adjuvant chemotherapy and full dose of radiotherapy. This approach has acceptable toxicity.

No significant financial relationships to disclose.

Pregancy after bilateral dysgerminoma treated with conservative surgery and BEP chemotherapy

16039

Background: Pregnancy after treatment of germ cell tumours of ovary is common. However patients with bilateral dysgerminoma treated with unilateral oophorectomy, wedge biopsy of opposite ovary, and conservation of uterus face difficulty in conception. This study was conducted with the objective to evaluate the fertility status of ovarian dysgerminoma patients treated with conservative surgery and BEP chemotherapy. Methods: Patients of bilateral dysgerminoma who underwent conservative surgery and chemotherapy with cisplatin 20 mg / m2 and etoposide 100 mg / m2 day 1 to 5 and bleomycin 30 mg on day 1, 8 and 15 of three weekly cycles were eligible. A normal AFP and beta HCG at baseline was required. Post treatment CT scans of abdomen and pelvis were obtained. Patients were regularly followed on monthly basis. Pregnancy was allowed 2 years after completion of last cycle of chemotherapy. Results: From January 1998 to December 2003, 11 patients were enrolled. Medain age was 16 years (range 13–18). All patients had complete disappearance of disease after treatment. Treatment related amenorrhea did not last beyond one year. During a median follow up of 5 years, all patients conceived and a total of 14 pregnancies were completed successfully.Three patients required use of clomiphene citrate for ovulation induction. No patient was treated with gonadotrophins. Six patients underwent lower segment caesarean section for obstetric indications and seven delivered vaginally. All babies were healthy without the signs of birth abnormalities or retardation. Conclusions: With conservative surgery and BEP chemotherapy for treatment of bilateral dysgerminoma the fertility is retained with good pregnancy outcome, when conception occurs at least two years after the last dose of chemotherapy.

No significant financial relationships to disclose.

Phase II feasibility of concurrent docetaxel and post mastectomy radiation after four cycles of AC chemotherapy in patients with high risk operable breast cancer: A trial of the Cancer Research Group Pakistan

10684

Background: Sequential use of docetaxel after four cycles of AC chemotherapy delays the postoperative radiation and can compromise loco-regional control. This delay can be avoided by starting radiotherapy concurrent with the docetaxel. We evaluated the feasibility of concurrent docetaxel and radiation therapy to chest wall and peripheral lymphatics after four cycles of AC chemotherapy. The preliminary results were reported in ASCO 2005 (Abstract 858). Methods: Females between 18–50 years, T2-T3 lesions, four or more positive nodes and hormone receptor negative tumors were eligible. Patients were enrolled after MRM. Four cycles of AC at 60/600 mg/m2 were followed by four cycles of docetaxel at 75mg/m2 every 21-days. Concurrent radiation to chest wall and peripheral lymphatics was started with the third cycle of docetaxel. A dose of 50 Gy in 5 weeks or equivalent was delivered. Successful completion of treatment in 18 out of 20 or 25 out of 30 patients was chosen as an index of feasibility. CTC version 2.0 of NCI and RTOG/EORTC Late Radiation Morbidity Scoring Scheme was used. Results: All the 30 enrolled patients successfully completed the planned treatment. Radiation was completed within 6 months of surgery in 27(90%) of the patients. Febrile neutropenia was seen in 5(16.7%). Grade-3 neutropenia and diarrhea in 8(26.7%) and 6(20%) respectively. Grade-3 dermatitis in the radiated area was seen in 2(6.7%) and grade-2 in 5(16.7%). Late toxicity included grade-2 skin atrophy and telangiectasia in radiated area in 6(20%) each. At a median follow up of 20 months (range 9–25 months) two local recurrences and two systemic relapses have been seen. Conclusion: This treatment schedule is feasible and safe in patients with high-risk operable breast cancer. It allows delivery of post mastectomy radiation within 6 months of surgery in patients undergoing sequential AC-docetaxel chemotherapy.

No significant financial relationships to disclose.

Phase II study of gemcitabine concurrent with radiation in locally advanced squamous cell carcinoma of head and neck: Trial of the Cancer Research Group Pakistan

15520

Background: The optimum radiosensitizing dose and schedule of gemcitabine for squamous cell carcinoma of head and neck are not known. The objectives of this study were to evaluate the efficacy and toxicity of weekly gemcitabine as a radiosensitizer concurrent with radical radiotherapy in locally advanced head and neck cancer. Method: Thirty-nine patients with stage III or IV B inoperable carcinoma of head and neck were enrolled. Eligible patients had histopathologically confirmed squamous cell carcinoma with age between 18–70 years. Patients had a KPS >70 with an adequate marrow, hepatic and renal function. No prior chemotherapy or radiotherapy was allowed. Patients with nasopharyngeal, glottic or sub-glottic cancer were excluded. Gemcitabine 150 mg/m2 or a total dose not exceeding 200 mg was given on day 1,8,15,22,29, and 36 during radiation treatment. Gemcitabine was infused in 200 ml of normal saline in 2 hours and radiation was delivered two hours after the completion of gemcitabine infusion. Conventional fractionation was used to deliver a total dose of 66 Gy. CTC version 2.0 of NCI and RTOG/EORTC Late Radiation Morbidity Scoring Scheme were used for evaluation of toxicity and RECIST was used for response evaluation. Results: Only 35 patients were considered evaluable for response. Complete response was seen in 8 (22.9%) (95% CI; 10.4–40.1%), partial response in 25 (71.4%), with an overall response rate of 94.3% (95% CI; 80.8–99.3%). All the thirty-nine patients were evaluable for toxicity. Grade 3 and 4 mucositis was seen in 28 (71.8%) and 2 (5.1%) patients respectively. Grade 3 pharyngeal toxicity was seen in 6 (15.4%). One patient developed pharyngo-cutaneous fistula. Despite vigorous symptomatic and supportive care acute toxicities led to treatment interruption in 16 (41%) of patients. Conclusion: Weekly gemcitabine at a dose of 150mg/m2 concurrent with radiation therapy gives a high overall response rate and a high rate of acute toxicity.

No significant financial relationships to disclose.

Docetaxel and cisplatin combination chemotherapy for advanced epithelial ovarian cancer with bulky residual disease

15030

Background: The combination of docetaxel and cisplatin as an alternative to the gold standard carboplatin and paclitaxel chemotherapy has not been explored in our patients. Docetaxel is more potent of the taxanes, therefore, this combination might yield a better outcome. This phase II study was designed to evaluate the efficacy and toxicity of docetaxel and cisplatin combination in epithelial ovarian cancer with bulky residual disease. Methods: Thirty-two new patients were enrolled between November 2003 and August 2005. Eligible patients had histopatholgically confirmed epithelial ovarian cancer, were older than 18 years and had FIGO stage IIC-IV cancer with bulky residual disease after primary cytoreductive surgery. Patients had a KPS >70 with adequate marrow and hepatic function. Patients with creatinine clearance by Cockroft-Gault formula of >60 ml/min were included. Written informed consent was obtained. Patients with diabetes mellitus, peripheral neuropathy, or cardiac co morbidity were excluded. Docetaxel and cisplatin were given at a dose of 75 mg/m2 each on day-1 of a 21-day cycle. Dexamethasone 8 mg was given thrice before and thrice after and tropisetron 5mg was given one hour before and 12 hours after chemotherapy. Docetaxel was given in 250 ml of NaCl in one-hour followed by cisplatin 75 mg/m2 in 1L of NaCl in 3 hours with pre and post hydration. NCI toxicity criteria version 2.0 and RECIST was used for evaluation. Results: Thirty patients were evaluable for response and toxicity. Final evaluation revealed CR in 12 (40%) (95% CI, 22.7–59.4%), PR in 14 (46.6%) with an ORR of 86.6% (95% CI, 69.3–96.2%). Three (10%) had SD and 1 (3.33) had PD. Grade 2 toxicity included alopecia 18 (60%), vomiting 6 (20%), diarrhea 7 (23.3%) and stomatitis in 5 (16%). Grade 3 and 4 neutropenia were seen in 12 (40%) and 9 (30%) respectively. Sensory neuropathy of grade 1 and 2 was seen in 4 (13.3%) and 2 (6.7%) respectively. Conclusion: Docetaxel and cisplatin combination chemotherapy is an effective and safe regimen in epithelial ovarian cancer with bulky residual disease. It gives a high overall response rate and has a manageable toxicity profile.

No significant financial relationships to disclose.