A phase II trial of gemcitabine and erlotinib followed by ChemoProton therapy plus capecitabine and oxaliplatin for locally advanced pancreatic cancer

Background

Epidermal growth factor receptor (EGFR) is overexpressed in pancreatic cancer. EGFR expression plays a potentially important role in modulation of tumor sensitivity to either chemotherapy or radiotherapy. Erlotinib is a receptor tyrosine kinase inhibitor with specificity for EGFR/HER1. A phase II trial was conducted to explore the efficacy of a regimen utilizing erlotinib and proton therapy.

Methods

Patients with unresectable or borderline resectable non-metastatic adenocarcinoma of the pancreas were included. Patients received 8-week systemic treatment with gemcitabine 1,000 mg/m² and erlotinib 100 mg (GE). If there was no evidence of metastatic disease after GE, then patients preceded with proton therapy to 50.4 Gy in 28 fractions with concurrent capecitabine 825 mg/m² (CPT). This was followed with oxaliplatin 130 mg/m² and capecitabine 1,000 mg/m² (CapOx) for 4 cycles. The primary study objective was 1-year overall survival (OS). The benchmark was 43% 1-year survival as demonstrated in RTOG/NRG 98-12. The Kaplan-Meier method was used to estimate the one-year OS and the median OS and progression-free survival (PFS).

Results

The study enrolled 9 patients ages 47–81 years old (median 62) between January 2013 and March 2016, when the trial was closed due to low patient accrual. The 1-year OS rate was 55.6% (95% CI: 31% to 99%). The median OS was 14.1 months (95% CI: 11.4–NE) and the median PFS was 10.8 months (95% CI: 7.44–NE). A majority of patients completed CPT and GE, but only 33.3% completed the four cycles of CapOx. A third of patients experienced grade 3 toxicities, which were all hepatic along with one patient who also had grade 3 diarrhea. There were no grade 4 or 5 toxicities. Four patients were enrolled with borderline resectable disease, three of which were eligible for pancreaticoduodenectomy after GE and CPT treatment. One of two patients who underwent resection had a negative margin.

Conclusions

This regimen for locally advanced pancreatic cancer (LAPC) exceeded the pre-specified benchmark and was safe and well tolerated. Additional investigations utilizing more current systemic treatment regimens with proton therapy are warranted.

Trial Registration

ClinicalTrials.gov identifier (NCTNCT01683422).

Proton stereotactic body radiation therapy for liver metastases-results of 5-year experience for 81 hepatic lesions

Background

To report on our institutional experience using Proton stereotactic body radiation therapy (SBRT) for patients with liver metastases.

Methods

All patients with liver metastases treated with Proton SBRT between September 2012 and December 2017 were retrospectively analyzed. Local control (LC) and overall survival (OS) were estimated using the Kaplan-Meier method calculated from the time of completion of Proton SBRT. LC was defined according to Response Evaluation Criteria in Solid Tumors (RECIST) guidelines (version 1.1). Toxicity was graded according to Common Terminology Criteria for Adverse Events (CTCAE) version 4.0.

Results

Forty-six patients with 81 lesions were treated with Proton SBRT. The median age was 65.5 years old (range, 33-86 years) and the median follow up was 15 months (range, 1-54 months). The median size of the gross tumor volume (GTV) was 2.5 cm (range, 0.7-8.9 cm). Two or more lesions were treated in 56.5% of patients, with one patient receiving treatment to a total of five lesions. There were 37 lesions treated with a biologically effective dose (BED) ≤60, 9 lesions with a BED of 61-80, 22 lesions with a BED of 81-100, and 13 lesions with a BED >100. The 1-year and 2-year LC for all lesions was 92.5% (95% CI, 82.7% to 96.8%). The grade 1 and grade 2 toxicity rates were 37% and 6.5%, respectively. There were no grade 3 or higher toxicities and no cases of radiation-induced liver disease (RILD).

Conclusions

Proton SBRT for the treatment of liver metastases has promising LC rates with the ability to safely treat multiple liver metastases. Accrual continues for our phase II trial treating liver metastases with Proton SBRT to 60 GyE (Gray equivalent) in 3 fractions.

Multicenter phase II trial (SWOG S1609, cohort 51) of ipilimumab and nivolumab in metastatic or unresectable angiosarcoma: a substudy of dual anti-CTLA-4 and anti-PD-1 blockade in rare tumors (DART)

Purpose

Angiosarcoma is a rare aggressive endothelial cell cancer with high mortality. Isolated reports suggest immune checkpoint inhibition efficacy in angiosarcoma, but no prospective studies have been published. We report results for angiosarcoma treated with ipilimumab and nivolumab as a cohort of an ongoing rare cancer study.

Methods

This is a prospective, open-label, multicenter phase II clinical trial of ipilimumab (1 mg/kg intravenously every 6 weeks) plus nivolumab (240 mg intravenously every 2 weeks) for metastatic or unresectable angiosarcoma. Primary endpoint was objective response rate (ORR) per RECIST 1.1. Secondary endpoints include progression-free (PFS) and overall survival, and toxicity. A two-stage design was used.

Results

Overall, there were 16 evaluable patients. Median age was 68 years (range, 25–81); median number of prior lines of therapy, 2. Nine patients had cutaneous and seven non-cutaneous primary tumors. ORR was 25% (4/16). Sixty per cent of patients (3/5) with primary cutaneous scalp or face tumors attained a confirmed response. Six-month PFS was 38%. Altogether, 75% of patients experienced an adverse event (AE) (at least possibly related to drug) (25% grade 3–4 AE); 68.8%, an immune-related AE (irAE) (2 (12.5%), grade 3 or 4 irAEs (alanine aminotransferase/aspartate aminotransferase increase and diarrhea)). There were no grade 5 toxicities. One of seven patients in whom tumor mutation burden (TMB) was assessed showed a high TMB (24 mutations/mb); that patient achieved a partial response (PR). Two of three patients with PDL1 immunohistochemistry assessed had high PDL1 expression; one achieved a PR.

Conclusion

The combination of ipilimumab and nivolumab demonstrated an ORR of 25% in angiosarcoma, with three of five patients with cutaneous tumors of the scalp or face responding. Ipilimumab and nivolumab warrant further investigation in angiosarcoma.

Trial registration number

NCT02834013.

Anthracycline-induced cardiotoxicity: A case report and review of literature

BACKGROUND

Doxorubicin and other anthracycline derivatives inhibit topoisomerase II and is an important class of cytotoxic chemotherapy in cancer treatment. The use of anthracycline is limited by dose-dependent cardiotoxicity, which may manifest initially as asymptomatic cardiac dysfunction with subsequent progression to congestive heart failure. Despite baseline assessment and periodic monitoring of cardiac function for patients receiving anthracycline agents, there are unmet needs in prediction and prevention of anthracycline-induced cardiotoxicity (AIC).

CASE SUMMARY

A 35-year-old African American female was found to have a 9-cm high-grade osteosarcoma of right femur and normal baseline cardiac function with left ventricular ejection fraction of approximately 60%-70% determined by transthoracic and dobutamine stress echocardiogram. She underwent perioperative doxorubicin and cisplatin chemotherapy with 3 cycles before surgery and 3 cycles after surgery, and received a total of 450 mg/m² doxorubicin at the end of her treatment course. She was evaluated regularly during chemotherapy without any cardiac or respiratory symptoms. Approximately two months after her last chemotherapy, the patient presented to the emergency department with dyspnea for one week and was intubated for acute hypoxic respiratory failure. Echocardiogram showed an ejection fraction of 5%-10% with severe biventricular failure. Despite attempts to optimize cardiac function, the patient’s hemodynamic status continued to decline, and resuscitation was not successful on the seventh day of hospitalization. The autopsy showed no evidence of osteosarcoma, and the likely cause of death was cardiac failure with the evidence of pulmonary congestion, liver congestion, and multiple body cavity effusions.

CONCLUSION

We present a case of 35-year-old African American female developing cardiogenic shock shortly after receiving a cumulative dose of 450 mg/m² doxorubicin over 9 mo. Cardiac monitoring and management of patients receiving anthracycline chemotherapy have been an area of intense research since introduction of these agents in clinical practice. We have reviewed literature and recent advances in the prediction and prevention of AIC. Although risk factors currently identified can help stratify patients who need closer monitoring, there are limitations to our current understanding and further research is needed in this field.

795 A multicenter phase II trial (SWOG S1609, cohort 51) of ipilimumab and nivolumab in metastatic or unresectable angiosarcoma: a substudy of dual anti-CTLA-4 and anti-PD-1 blockade in rare tumors (DART)

Background

Angiosarcoma is a rare cancer of endothelial cells that can be aggressive and carries a high mortality. A subset of angiosarcomas are characterized by high tumor mutational burden (TMB) and UV light exposure DNA mutational signature. Isolated case reports have suggested clinical efficacy of immune checkpoint blockade in angiosarcoma; no prospective studies of immune checkpoint inhibition in angiosarcoma have been reported. We report efficacy analysis results for patients with advanced or unresectable angiosarcoma treated with ipilimumab and nivolumab as a cohort of an ongoing phase II study for rare cancers (NCT02834013).

Methods

This is a prospective, open-label, multicenter phase II clinical trial of ipilimumab (1mg/kg IV q6weeks) plus nivolumab (240mg IV q2weeks) for patients with metastatic or unresectable angiosarcoma. Primary endpoint is objective response rate as assessed by RECIST v1.1, including measurable cutaneous disease that can be followed by photography. Secondary endpoints include PFS, OS, stable disease at six months, and toxicity. A two-stage design is used with six patients in the first stage and an additional ten patients in the second stage.

Results

At data cutoff, 16 patients with angiosarcoma were enrolled. Median age was 68 years (25-81 years). Median number of prior lines of therapy was 2 (0-5). 9 patients had cutaneous primary tumors of any cutaneous site, 7 had non-cutaneous primary tumors. ORR for all patients was 25% (4/16, table 1, figure 1). Subgroup analysis revealed that 60% (3/5) of patients with primary cutaneous tumors of the scalp or face had a confirmed objective response. 6-month PFS was 38%. 75% of patients experienced an adverse event (AE), and 25% experienced a grade 3-4 AE. 68.8% experienced an immune related AE (irAE), and 2 (12.5%) developed grade 3 or 4 irAEs. Grade 3-4 irAEs were ALT and AST increase and diarrhea. There were no grade 5 toxicities.

Conclusions

The combination of ipilimumab and nivolumab was well tolerated and had an ORR of 25% in angiosarcoma regardless of primary site, with 3 of 5 patients with cutaneous tumors of the scalp or face responding. Ipilimumab and nivolumab warrant further investigation in angiosarcoma.

Acknowledgements

Funding: National Institutes of Health/National Cancer Institute grant awards CA180888, CA180819, CA180868; and in part by Bristol-Myers Squibb Company

Trial Registration

NCT02834013

Ethics Approval

This study was approved by the NCI CIRB.

Targeted and novel therapy in advanced gastric cancer

The systemic treatment options for advanced gastric cancer (GC) have evolved rapidly in recent years. We have reviewed the recent data of clinical trial incorporating targeted agents, including inhibitors of angiogenesis, human epidermal growth factor receptor 2 (HER2), mesenchymal-epithelial transition, epidermal growth factor receptor, mammalian target of rapamycin, claudin-18.2, programmed death-1 and DNA. Addition of trastuzumab to platinum-based chemotherapy has become standard of care as front-line therapy in advanced GC overexpressing HER2. In the second-line setting, ramucirumab with paclitaxel significantly improves overall survival compared to paclitaxel alone. For patients with refractory disease, apatinib, nivolumab, ramucirumab and TAS-102 have demonstrated single-agent activity with improved overall survival compared to placebo alone. Pembrolizumab has demonstrated more than 50% response rate in microsatellite instability-high tumors, 15% response rate in tumors expressing programmed death ligand 1, and non-inferior outcome in first-line treatment compared to chemotherapy. This review summarizes the current state and progress of research on targeted therapy for advanced GC.

Concomitant KRAS and BRAF mutations in colorectal cancer

BRAF and KRAS are two key oncogenes in the RAS/RAF/MEK/MAP-kinase signaling pathway. While previously considered mutually exclusive, concomitant mutations in both KRAS and BRAF genes have been identified in colorectal cancer (CRC). The clinical outcome of these patients remains undetermined. We present the clinical course of two patients with CRC harboring mutations at codon 12 of KRAS and BRAF non-V600E mutations. More research is needed to determine the clinical-pathological effect of these simultaneous mutations of KRAS and BRAF in CRC on disease course and treatment outcome.

Sustained complete response to erlotinib in squamous cell carcinoma of the head and neck: A case report

BACKGROUND

Squamous cell carcinoma of head and neck (SCCHN) is the fifth most common cancer worldwide. Inhibition of epidermal growth factor receptor signaling has been shown to be a critical component of therapeutic option. Herein, we report a case of durable complete response to erlotinib.

CASE SUMMARY

An 81-year-old Caucasian male who presented with metastatic poorly differentiated squamous cell carcinoma of right cervical lymph nodes (levels 2 and 3). Imaging studies including (18)F-fluorodeoxyglucose positron emission tomography/computed tomography (CT) and contrast-enhanced CT scan of neck and chest did not reveal any other disease elsewhere. Panendoscopic examination with random biopsy did not reveal malignant lesion in nasopharynx, oropharynx, and larynx. He underwent modified neck dissection and postoperative radiation. Within 2 mo after completion of radiation, he developed local recurrence at right neck, which was surgically removed. Two mo after the salvage surgery, he developed a second recurrence at right neck. Due to suboptimal performance status and his preference, he started erlotinib treatment. He achieved partial response after first 2 mo of erlotinib treatment, then complete response after total 6 mo of erlotinib treatment. He developed sever skin rash and diarrhea including Clostridium difficile infection during the course of erlotinib treatment requiring dose reduction and eventual discontinuation. He remained in complete remission for more than two years after discontinuation of erlotinib.

CONCLUSION

We report a case of metastatic SCCHN achieving durable complete response from erlotinib. Patient experienced skin rash and diarrhea toxicities which were likely predictors of his treatment response.

Thyroid dysfunction from inhibitor of fibroblast growth factor receptor

Background

Thyroid dysfunction has not been previously reported in clinical trials of selective fibroblast growth factor receptor (FGFR) inhibitors including AZD4547. Herein, we report a case of worsening hypothyroidism in a patient with advanced urothelial cancer treated with AZD4547.

Case presentation

An 80-year-old Caucasian female with metastatic urothelial carcinoma failed first-line chemotherapy with gemcitabine and carboplatin and second-line treatment with atezolizumab, an inhibitor of programmed cell death ligand 1. She developed hypothyroidism at completion of atezolizumab treatment and responded to levothyroxine. Subsequently she was enrolled to a phase II study and received AZD4547 due to an actionable mutation at FGFR3 found in tumor biopsy. Two months later, she experienced recurrent hypothyroidism symptoms, and was hospitalized twice for small bowel obstruction. Her thyroid stimulating hormone level was significantly increased to 2957 uIU/mL (reference range 0.8-7.7 uIU/mL). Her levothyroxine dose was increased accordingly. Her thyroid function returned to normal 1 month afterwards, and small bowel obstruction did not recur.

Conclusion

Further reports and studies will be needed to confirm the relationship between AZD4547 and hypothyroidism. Based on this observation and possible mechanisms for thyroid dysfunction discussed in this paper, routine thyroid function monitoring in patients receiving FGFR inhibitor should be considered.

Conservative management of nivolumab-induced pericardial effusion: a case report and review of literature

Background

Nivolumab is an immune checkpoint inhibitor targeting programmed death-1 protein and has been approved for the treatment of multiple advanced malignancies. Adverse effects of immune checkpoint inhibitors are distinct from conventional cytotoxic chemotherapy and can be life-threatening if left unrecognized. Here, we present a case of nivolumab-induced pericardial effusion successfully managed with high-dose corticosteroids.

Case presentation

A 70-year-old Caucasian female with a history of 50-pack-year cigarette smoking was diagnosed of recurrent adenocarcinoma of lung after initial surgery. She progressed through multiple lines of chemotherapy and was eventually started on nivolumab. She developed a large pericardial effusion, grade 3 by Common Terminology Criteria for Adverse Events v4.0, about 4 days after receiving first nivolumab treatment. She was treated with oral prednisone at 1 mg/kg daily with gradual resolution of pericardial effusion over 5 weeks while she still received nivolumab every 2 weeks. Prednisone treatment was eventually tapered off about 10 weeks from initial nivolumab treatment. However 1 week after stopping prednisone, she again presented with shortness of breath and bilateral ankle edema, imaging confirmed recurrent pericardial effusion measuring 2.8 cm. Nivolumab was stopped and patient was again started back on prednisone 1 mg/kg daily which resulted in complete resolution of pericardial effusion in 3 weeks. Nivolumab was resumed 1 week afterwards while patient was on tapering dose of prednisone. There was no recurrent pericardial effusion when she continued low-dose prednisone during the remaining course of nivolumab treatment.

Conclusions

With increasing use of immune checkpoint inhibitors, clinicians need to be aware of the unusual immune-related adverse events in order to provide timely management and effective patient care. To our knowledge, this is the first reported case of immune-related pericardial effusion from nivolumab successfully managed with high-dose corticosteroids. Furthermore, recurrent pericardial effusion was prevented by using low-dose corticosteroids as maintenance in order for patient to continue nivolumab treatment.

A phase I trial of Proton stereotactic body radiation therapy for liver metastases

Background

A phase I trial to determine the maximum tolerated dose (MTD) of Proton stereotactic body radiation therapy (SBRT) for liver metastases in anticipation of a subsequent phase II study.

Methods

An institutional IRB approved phase I clinical trial was conducted. Eligible patients had 1-3 liver metastases measuring less than 5 cm, and no metastases location within 2 cm of the GI tract. Dose escalation was conducted with three dose cohorts. The low, intermediate, and high dose cohorts were planned to receive 36, 48, and 60 respectively to the internal target volume (ITV) in 3 fractions. At least 700 mL of normal liver had to receive <15. Dose-limiting toxicity (DLT) included acute grade 3 liver, intestinal or spinal cord toxicity or any grade 4 toxicity. The MTD is defined as the dose level below that which results in DLT in 2 or more of the 6 patients in the highest dose level cohort.

Results

Nine patients were enrolled (6 male, 3 female): median age 64 years (range, 33-77 years); median gross tumor volume (GTV) 11.1 mL (range, 2.14-89.3 mL); most common primary site, colorectal (5 patients). Four patients had multiple tumors. No patient experienced a DLT and dose was escalated to 60 in 3 fractions without reaching MTD. The only toxicity within 90 days of completion of treatment was one patient with a grade 1 skin hyperpigmentation without tenderness or desquamation. Two patients in the low dose cohort had local recurrence and repeat SBRT was done to previously treated lesions without any toxicities.

Conclusions

Biologically ablative Proton SBRT doses are well tolerated in patients with limited liver metastases with no patients experiencing any grade 2+ acute toxicity. Results from this trial provide the grounds for an ongoing phase II Proton SBRT study of 60 over 3 fractions for liver metastases.

Safety and pharmacokinetics of cabazitaxel in patients with hepatic impairment: a phase I dose-escalation study

Purpose

Cabazitaxel has not been studied in patients with hepatic impairment (HI). This phase I study assessed cabazitaxel safety and pharmacokinetics in patients with HI.

Methods

Patients with advanced, non-hematologic cancer, and normal hepatic function (Cohort 1: C-1), or mild (C-2), moderate (C-3), severe (C-4) HI received cabazitaxel starting doses of 25, 20, 10, and 10 mg/m², respectively. Doses were escalated in patients with HI based on Cycle 1 dose-limiting toxicities (DLTs). Adverse events and the cabazitaxel pharmacokinetic profile were assessed.

Results

In C-2, three patients receiving cabazitaxel 25 mg/m² experienced DLTs; maximum tolerated dose (MTD) was 20 mg/m². In C-3, two patients receiving 20 mg/m² experienced DLTs; MTD was 15 mg/m². C-4 was discontinued early due to DLTs. The most frequent cabazitaxel-related, grade 3–4 toxicity was neutropenia (42%). Cabazitaxel clearance normalized to body surface area (CL/BSA) was lower in C-1 (geometric mean [GM] 13.4 L/h/m²) than expected (26.4 L/h/m²), but similar in C-2 (23.5 L/h/m²) and C-3 (27.9 L/h/m²). CL/BSA in C-4 was 18.1 L/h/m². Compared with C-2, CL/BSA increased 19% in C-3 (GM ratio 1.19; 90% CI 0.74–1.91), but decreased 23% in C-4 (0.77; 0.39–1.53). Cabazitaxel free fraction was unaltered. No significant correlation was found between grade 3–4 toxicities and pharmacokinetic parameters.

Conclusions

Mild–moderate HI did not cause substantial decline in cabazitaxel clearance. Cabazitaxel dose reductions in patients with mild–moderate HI, and a contraindication in patients with severe HI, are justified based on safety data.

Nanovectors for anti-cancer drug delivery in the treatment of advanced pancreatic adenocarcinoma

Liposome, albumin and polymer polyethylene glycol are nanovector formulations successfully developed for anti-cancer drug delivery. There are significant differences in pharmacokinetics, efficacy and toxicity between pre- and post-nanovector modification. The alteration in clinical pharmacology is instrumental for the future development of nanovector-based anticancer therapeutics. We have reviewed the results of clinical studies and translational research in nanovector-based anti-cancer therapeutics in advanced pancreatic adenocarcinoma, including nanoparticle albumin-bound paclitaxel and nanoliposomal irinotecan. Furthermore, we have appraised the ongoing studies incorporating novel agents with nanomedicines in the treatment of pancreatic adenocarcinoma.

Neoadjuvant treatment for resectable pancreatic adenocarcinoma

Pancreatic adenocarcinoma is the fourth leading cause of cancer mortality in the United States in both men and women, with a 5-year survival rate of less than 5%. Surgical resection remains the only curative treatment, but most patients develop systemic recurrence within 2 years of surgery. Adjuvant treatment with chemotherapy or chemoradiotherapy has been shown to improve overall survival, but the delivery of treatment remains problematic with up to 50% of patients not receiving postoperative treatment. Neoadjuvant therapy can provide benefits of eradication of micrometastasis and improved delivery of intended treatment. We have reviewed the findings from completed neoadjuvant clinical trials, and discussed the ongoing studies. Combinational cytotoxic chemotherapy such as fluorouracil, leucovorin, irinotecan, and oxaliplatin and gemcitabine plus nanoparticle albumin-bound (nab)-paclitaxel, active in the metastatic setting, are being studied in the neoadjuvant setting. In addition, novel targeted agents such as inhibitor of immune checkpoint are incorporated with cytotoxic chemotherapy in early-phase clinical trial. Furthermore we have explored the utility of biomarkers which can personalize treatment and select patients for target-driven therapy to improve treatment outcome. The treatment of resectable pancreatic adenocarcinoma requires multidisciplinary approach and novel strategies including innovative trials to make progress.

Effects of Chinese herbal medicine in combination with mitomycin C on gastric cancer cells

Chinese herbal medicine (CHM) is frequently used by cancer patients in Chinese community. It remains largely unknown about the interaction between CHM and chemotherapeutic agents. Herein, we evaluated 3 commonly used CHM formulas for cancer patients: Bu-Zhong-Yi-Qi-Tang (BZYQT), Bao-Yuan-Tang (BYT), and Ju-Yuan-Jian (JYJ). We examined the effects of these 3 formulas in human gastric cancer cells MKN-74, in terms of cytotoxicity and apoptosis induction when used alone or in combination with mitomycin C (MMC). Cytotoxicity was determined by tetrazolium dye colorimetric assay. The 10% inhibitory concentration of CHM was used in this study. Cells were first exposed to CHM or phosphate buffered saline (as control) for 48 h. Then MMC at final concentration of 0.25 μg/ml was added to media for another 24-h. Among these 3 CHM formulas, BZYQT showed the most pronounced effect in augmenting MMC-induced cytotoxicity. The viability of MKN-74 cells was decreased to 43.1% when treated with BZYQT and MMC, compared to 94.9% with MMC alone. We subsequently examined apoptosis induction by quantitative florescent microscopy and single-strand DNA enzyme-linked immunosorbent assay, and found BZYQT did not enhance MMC-induced apoptosis. Our findings indicate BZYQT in combination with MMC induces cell death in gastric cancer cells via non-apoptotic mechanism. Our results provide a rationale for further investigation in the interaction of CHM and anti-cancer treatment.

Combination antiangiogenic therapy and radiation in head and neck cancers

Tumor angiogenesis is a hallmark of advanced cancers and promotes invasion and metastasis. Over 90% of head and neck squamous cell carcinomas (HNSCC) express angiogenic factors such as vascular endothelial growth factor (VEGF). Several preclinical studies support the prognostic implications of angiogenic markers for HNSCC and currently this is an attractive treatment target in solid tumors. Since radiotherapy is one of the most commonly used treatments for HNSCC, it is imperative to identify the interactions between antiangiogenic therapy and radiotherapy, and to develop combination therapy to improve clinical outcome. The mechanisms between antiangiogenic agents and ionizing radiation are complicated and involve many interactions between the vasculature, tumor stroma and tumor cells. The proliferation and metastasis of tumor cells rely on angiogenesis/blood vessel formation. Rapid growing tumors will cause hypoxia, which up-regulates tumor cell survival factors, such as hypoxia-inducing factor-1α (HIF-1α) and vascular endothelial growth factor (VEGF), giving rise to more tumor proliferation, angiogenesis and increased radioresistance. Thus, agents that target tumor vasculature and new tumor vessel formation can modulate the tumor microenvironment to improve tumor blood flow and oxygenation, leading to enhanced radiosensitivity. In this review, we discuss the mechanisms of how antiangiogenic therapies improve tumor response to radiation and data that support this combination strategy as a promising method for the treatment of HNSCC in the future.

Absence of interaction of cabazitaxel on the pharmacokinetics of midazolam: Results of a drug–drug interaction study in patients with advanced solid tumors

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Background: Cabazitaxel (Cbz) is approved in combination with prednisone/prednisolone for the treatment of men with hormone-refractory metastatic prostate cancer previously treated with a docetaxel-containing treatment regimen. In vitro studies showed that Cbz is mainly metabolized through CYP3A, resulting in inhibition of this family of enzymes. Midazolam (Mdz) is primarily metabolized by CYP3A4. We aimed to determine the effect of Cbz on CYP3A activity by comparing the pharmacokinetic (PK) properties of Mdz when administered alone and following co-administration with Cbz. Methods: An ongoing safety and PK study of Cbz in patients with metastatic or locally advanced solid tumors and varying degrees of hepatic impairment (NCT01140607) included a cohort with normal hepatic function to assess the effect of a single Cbz dose on the PK profile of a single dose of Mdz. This was an open-label, two-period, fixed-sequence study in patients aged between 45 and 60 years with advanced solid tumors and normal hepatic function. A single dose of Mdz (2 mg) was administered orally alone (Day –1) and at the end of a 1-hour infusion of Cbz (25 mg/m2) (Day 1), with a 24-hour interval between the two administrations of Mdz. Endpoints included AUC and AUClastof Mdz with and without Cbz administration, and safety evaluations. Results: Of the 13 patients enrolled and treated in the cohort, 11 patients were included in the PK analysis. Exposure (AUC and AUClast) and other PK parameters after a single administration of Mdz alone and in combination with Cbz (Day 1) were similar. The AUC ratio for Mdz administered alone or with Cbz was 0.97 (90% CI: 0.76–1.23). The AUClast ratio for Mdz administered alone or with Cbz was 1.04 (90% CI: 0.81–1.34). All 13 patients had ≥1 adverse event (AE), 11 (84.6%) experienced a Grade 3–4 AE, and 4 (30.8%) experienced a serious AE. The majority of Grade 3–4 AEs were haematological and no new or unexpected safety findings were observed. Conclusions: In this study, Cbz did not increase the plasma exposure of Mdz. This indicates that Cbz is not a CYP3A inhibitor in the clinical setting and can be administered in combination with drugs metabolized by CYP3A. Clinical trial information: NCT01140607.

Publish, not perish: Introducing Experimental Hematology & Oncology

As a scientific discipline, medicine can only be advanced by experimentation. Experimentation could either validate or refute a hypothesis. Unfortunately, today's publication climate strongly favors publication of positive research findings, especially with clinical trials. Experimental Hematology & Oncology (eHO) is a new open access online journal that emphasizes preclinical, patient-oriented and translational aspects of research. The journal differentiates from others in the field by making a deliberate effort in publishing clinical trials with "negative" results and basic science studies with provocative findings. The focus of the peer-review mechanism for eHO will be on the technical merit of the study and not on demanding a long list of additional experiments that hinders rapid information dissemination.

Clinical significance of E2F1 protein expression in non-small cell lung cancer

BACKGROUND

The transcription factor E2F1 has been implicated in cell cycle control and DNA damage response. Paradoxically, E2F1 can promote apoptosis and function as tumor suppressor. In non-small cell lung cancer (NSCLC), there are conflicting data for clinical significance of E2F1 expression. In this study, we investigated the protein expression of E2F1 in patients with stage I-III NSCLC, and its correlation with clinical outcome.

RESULTS

56 paired adjacent non-tumor/tumor matched samples were prospectively obtained from patients undergoing surgery for stage I-III NSCLC at Taipei Veterans General Hospital. The protein expression of E2F1 was determined by Western blot analysis. The levels of E2F1 protein were significantly higher in tumor samples than in non-tumor lung specimens (P = 0.008). Overexpression of E2F1 was defined as a more than 2-fold expression in the tumorous sample compared with the corresponding nontumorous one, and was noted in 21 patients (37.5%). There was no significant difference in overall survival (P = 0.44) or probability of freedom from recurrence (P = 0.378) between patients with E2F1 overexpression vs. non-overexpressors. Additionally, there was no significant association between E2F1 overexpression and any clinicopathologic parameter such as histological type, stage, or angiolymphatic invasion of tumor.

CONCLUSION

E2F1 protein is frequently overexpressed in NSCLC. There is no correlation between E2F1 protein expression and clinical outcome such as survival and freedom from progression.

Deprivation of arginine by recombinant human arginase in prostate cancer cells

BACKGROUND

Recombinant human arginase (rhArg) has been developed for arginine deprivation therapy in cancer, and is currently under clinical investigation. During pre-clinical evaluation, rhArg has exhibited significant anti-proliferative activity in cancer cells deficient in the expression of ornithine carbamoyl transferase (OCT). Interestingly, a variety of cancer cells such as melanoma and prostate cancer deficient in argininosuccinate synthetase (ASS) are sensitive to arginine deprivation by arginine deiminase. In this study, we investigated levels of gene expression of OCT and ASS, and the effects of rhArg in human prostate cancer cells: LNCaP (androgen-dependent), PC-3 and DU-145 (both androgen-independent).

RESULTS

Quantitative real-time PCR showed minimal to absent gene expression of OCT, but ample expression of ASS expression in all 3 cell lines. Cell viability assay after 72-h exposure of rhArg showed all 3 lines had half maximal inhibitory concentration less than or equal to 0.02 U/ml. Addition of ornithine to cell culture media failed to rescue these cells from rhArg-mediated cytotoxicity.Decreased phosphorylation of 4E-BP1, a downstream effector of mammalian target of rapamycin (mTOR), was noted in DU-145 and PC-3 after exposure to rhArg. Moreover, there was no significant apoptosis induction after arginine deprivation by rhArg in all 3 prostate cancer cell lines.

CONCLUSION

rhArg causes significant cytotoxicity in LNCaP, DU-145 and PC-3 prostate cancer cells which all demonstrate decreased OCT expression. Inhibition of mTOR manifested by hypophosphorylation of 4E-BP1 suggests autophagy is involved as alternative cell death mechanism. rhArg demonstrates a promising novel agent for prostate cancer treatment.

Abstract 2663: Phase I study of azacitidine and cisplatin in patients with advanced head and neck or non-small cell lung cancer

Background: DNA hypomethylation agents such as azacitidine may be used for epigenetic sensitization of cisplatin treatment, and therefore leading to improvement of treatment outcome. We conducted a phase I study of azacitidine and cisplatin to determine safety, toxicity, and effect of global DNA methylation in peripheral blood mononuclear cells. Methods: Azacitidine was given as subcutaneous injection daily from day 1 to day 5, and cisplatin was given at 75 mg/m2 IV on day 8. The treatment was repeated every 28 days. Four patients received azacitidine 37 mg/m2 daily from day 1 to day 5 on dose level 1. Two patients were treated on dose level 2, and received azacitidine 60 mg/m2 daily from day 1 to day 5. Peripheral blood samples were collected before and after azacitidine treatment. DNA was extracted from peripheral blood mononuclear cells, and subjected to gas chromatography/mass spectrometry to measure the level of global DNA methylation, as reflected by the ratio of 5-methylcytosine to the sum of 5-methylcytosine and cytosine. Results: No patient had dose-limiting toxicities. Four patients completed at least 2 cycles of treatment, and were evaluated for clinical response by CT scan and DNA methylation effect. One partial response was noted in patient with metastatic tongue cancer after 2 cycles of treatment on dose level 1 of azacitidine. This patient received total 3 cycles of treatment and achieved free of progression for about 15 months on chemotherapy holiday. One patient with recurrent salivary gland cancer achieved stable disease after 2 cycles of treatment on dose level 2, and maintained in free of progression for more than 6 months after 4 cycles of treatment. There was inhibition of global DNA methylation after azacitidine treatment ranging from 12 to 36% in all 4 patients. Furthermore, the inhibition of global DNA methylation was associated with the increase of fetal hemoglobin in patients’ peripheral blood. Conclusion: Sequential administration of azacitidine followed by cisplatin is well tolerated, and demonstrates encouraging activity in patients with advanced head and neck cancer. This combination deserves further clinical investigation to study the correlation between clinical response and biological effects.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 2663. doi:1538-7445.AM2012-2663

Novel targeted therapeutics: inhibitors of MDM2, ALK and PARP

We reviewed preclinical data and clinical development of MDM2 (murine double minute 2), ALK (anaplastic lymphoma kinase) and PARP (poly [ADP-ribose] polymerase) inhibitors. MDM2 binds to p53, and promotes degradation of p53 through ubiquitin-proteasome degradation. JNJ-26854165 and RO5045337 are 2 small-molecule inhibitors of MDM2 in clinical development. ALK is a transmembrane protein and a member of the insulin receptor tyrosine kinases. EML4-ALK fusion gene is identified in approximately 3-13% of non-small cell lung cancer (NSCLC). Early-phase clinical studies with Crizotinib, an ALK inhibitor, in NSCLC harboring EML4-ALK have demonstrated promising activity with high response rate and prolonged progression-free survival. PARPs are a family of nuclear enzymes that regulates the repair of DNA single-strand breaks through the base excision repair pathway. Randomized phase II study has shown adding PARP-1 inhibitor BSI-201 to cytotoxic chemotherapy improves clinical outcome in patients with triple-negative breast cancer. Olaparib, another oral small-molecule PARP inhibitor, demonstrated encouraging single-agent activity in patients with advanced breast or ovarian cancer. There are 5 other PARP inhibitors currently under active clinical investigation.

Critical appraisal of the role of sorafenib in the management of hepatocellular carcinoma

Sorafenib is an oral multiple kinase inhibitor that blocks Raf, vascular endothelial growth factor receptor, and platelet-derived growth factor receptor. It has been approved in the US and Europe for the treatment of advanced hepatocellular carcinoma (HCC). Sorafenib has demonstrated a 44% increase in survival for advanced HCC patients, compared with best supportive care alone. We have reviewed the pharmacology, pivotal studies, and safety data for this agent. Sorafenib is the first systemic drug demonstrating a significant survival benefit, and is the standard of care for patients with advanced HCC for whom no potential curative option is available.

Pathological complete response after neoadjuvant chemotherapy with trastuzumab-containing regimen in gastric cancer: a case report

We report a 49-year-old Chinese male with locally advanced gastric adenocarcinoma achieving pathological complete response after neoadjuvant chemotherapy with trastuzumab-containing regimen. He underwent esophagogastroduodenoscopy in September 2009, which revealed a 2-cm gastric ulcer on the lesser curvature proximal to angularis. Biopsy of gastric ulcer showed moderately differentiated adenocarcinoma with overexpression of human epidermal growth factor receptor 2 (HER2) by immunohistochemistry and fluorescence in situ hybridization. Further workups with endoscopic ultrasound, computed tomography and positron emission tomography staged his cancer as T3N1M0. He received 3 cycles of neoadjuvant chemotherapy consisting of trastuzumab, oxaliplatin, docetaxel and capecitabine without severe toxicities except grade 2 diarrhea near the completion of cycle 3 requiring discontinuation of capecitabine. Afterwards, he received total gastrectomy with extended D2 lymph node dissections showing pathological complete response. He went on to receive 3 more cycles of chemotherapy postoperatively. The role of trastuzumab as a part of perioperative therapy in gastric cancer overexpressing HER2 is worth further investigation.

Pancytopenia associated with clonazepam

We report a case of a 48-year-old Chinese female with end-stage renal disease and chronic anemia on hemodialysis. Clonazepam was prescribed for myoclonus disorder two weeks prior to her hospitalization. Subsequently, she was hospitalized for neutropenic fever with thrombocytopenia and worsening anemia. Bone marrow examination demonstrated a markedly hypocellular marrow (10-20% total cellularity). Clonazepam was discontinued, with gradual improvement of thrombocytopenia, and neutropenia in 1-2 weeks. To our knowledge, this is the first reported case of pancytopenia associated with clonazepam. We recommend patients taking clonazepam to be monitored with regular complete blood count to check for clinically significant pancytopenia or thrombocytopenia.

Hypersensitivity reaction and acute immune-mediated thrombocytopenia from oxaliplatin: two case reports and a review of the literature

Background

Oxaliplatin is a platinum compound used in the treatment of gastrointestinal malignancies, including colorectal cancer. The incidence of hypersensitivity reaction in patients receiving oxaliplatin is approximately 15%, with severe reaction (grade 3 and 4) occurring in 2% of patients.

Case presentation

We report two patients with metastatic colorectal cancer who developed de novo hypersensitivity reaction and acute thrombocytopenia after oxaliplatin infusion. Both patients had oxaliplatin treatment several years before and exhibited hypersensitivity on the third dose of oxaliplatin in recent treatment. Oxaliplatin was discontinued when clinical reaction was identified. Both patients were confirmed to have strong oxaliplatin-induced IgG platelet-reactive antibodies. Both patients' thrombocytopenia resolved within two weeks after discontinuation of oxaliplatin. One patient had disease stabilization lasting for three months without chemotherapy. Both patients subsequently received other chemotherapeutic agents without evidence of hypersensitivity reaction or immune-mediated thrombocytopenia.

Conclusion

We recommend vigilant monitoring of complete blood count and signs and symptoms of bleeding after the occurrence of oxaliplatin-induced hypersensitivity to avoid serious complications of immune-mediated thrombocytopenia.

Recent advances in gastrointestinal oncology--updates and insights from the 2009 annual meeting of the American society of clinical oncology

We have reviewed the pivotal presentations related to gastrointestinal malignancies from 2009 annual meeting of the American Society of Clinical Oncology with the theme of "personalizing cancer care". We have discussed the scientific findings and the impact on practice guidelines and ongoing clinical trials. Adding trastuzumab to chemotherapy improved the survival of patients with advanced gastric cancer overexpressing human epidermal growth factor receptor 2. Gemcitabine plus cisplatin has become a new standard for first-line treatment of advanced biliary cancer. Octreotide LAR significantly lengthened median time to tumor progression compared with placebo in patients with metastatic neuroendocrine tumors of the midgut. Addition of oxaliplatin to fluoropyrimidines for preoperative chemoradiotherapy in patients with stage II or III rectal cancer did not improve local tumor response but increased toxicities. Bevacizumab did not provide additional benefit to chemotherapy in adjuvant chemotherapy for stage II or III colon cancer. In patients with resected stage II colon cancer, recurrence score estimated by multigene RT-PCR assay has been shown to provide additional risk stratification. In stage IV colorectal cancer, data have supported the routine use of prophylactic skin treatment in patients receiving antibody against epidermal growth factor receptor, and the use of upfront chemotherapy as initial management in patients with synchronous metastasis without obstruction or bleeding from the primary site.

Updates in Gastrointestinal Oncology - insights from the 2008 44th annual meeting of the American Society of Clinical Oncology

We have reviewed the pivotal presentations rcelated to colorectal cancer (CRC) and other gastrointestinal malignancies from 2008 annual meeting of the American Society of Clinical Oncology (ASCO). We have discussed the scientific findings and the impact on practice guidelines and ongoing clinical trials. The report on KRAS status in patients with metastatic CRC receiving epidermal growth factor receptor (EGFR) targeted antibody treatment has led to a change in National Comprehensive Cancer Network guideline that recommends only patients with wild-type KRAS tumor should receive this treatment. The results of double biologics (bevacizumab and anti-EGFR antibody) plus chemotherapy as first-line treatment in patients with metastatic CRC has shown a worse outcome than bevacizumab-based regimen. Microsatellite Instability has again been confirmed to be an important predictor in patients with stage II colon cancer receiving adjuvant treatment. Adjuvant gemcitabine therapy for pancreatic cancer was investigated by the CONKO-001 study; this resulted in superior survival as compared with observation and can be regarded as an acceptable option, without the addition of radiotherapy. The addition of bevacizumab to gemcitabine and erlotinib was not supior to gemcitabine and erlotinib for advanced disease. Second-line therapy for advanced pancreatic cancer with 5-fluorouracil and oxaliplatin resulted in a survival benefit. Irinotecan plus cisplatin and paclitaxel plus cisplatin result in similar survival when combined with radiotherapy for esophageal cancer. The novel fluoropyrimidine S1 appears to be active in gastric cancer, as a single agent or as combination therapy. Adjuvant intraperitoneal mitomycin-C may decrease the incidence of peritoneal recurrence of gastric cancer. Sorafenib is an effective agent in Asian patients with hepatocellular carcinoma secondary to hepatitis B; its utility in child's B cirrhosis remains to be proven. Sunitinib is also an active agent in hepatocellular carcinoma, and may represent an alterative to sorafenib for advanced disease. These and other important presentations from the 2008 ASCO annual meeting are discussed in this article.

Clinical Implications of Microsomal Prostaglandin E Synthase-1 Overexpression in Human Non–Small-Cell Lung Cancer

BACKGROUND

Microsomal prostaglandin E synthase-1 (mPGES-1) has recently been found to overexpress in human cancers, including non-small-cell lung cancer (NSCLC). However, the clinical value is largely unknown. The aim of this study was to investigate the associations between mPGES-1 expression in NSCLC and the clinical characteristics and survival outcome.

METHODS

Between 2001 and 2003, paired fresh tumorous and nontumorous samples were prospectively procured from patients undergoing surgery for NSCLC. The expression of mPGES-1 was assessed by using Western blot in 93 subjects and reverse transcriptase-polymerase chain reaction in 35. Overexpression of mPGES-1 was defined as a more than 2-fold expression in the tumorous sample compared with the corresponding nontumorous one. Immunohistochemistry was used to confirm its localization to the tumor cells. In a subset of 30 cases, cyclooxygenase-2 (COX-2) was also analyzed to assess its association with mPGES-1.

RESULTS

The protein and messenger RNA of mPGES-1 were both expressed at higher levels in the tumor samples (P < .001 and P = .006, respectively). The expressions of mPGES-1 and COX-2 were unrelated (P = .715). Overexpression of mPGES-1 protein was observed in 61 (65.6%) of 93 patients, but it was not significantly associated with the clinicopathologic characteristics or overall and disease-free survivals. However, mPGES-1 overexpression seemed to be associated with the likelihood of subsequent pulmonary metastases and a lower tendency for developing bony metastases (P = .001 and P = .006, respectively).

CONCLUSIONS

Our results demonstrated that mPGES-1 was overexpressed in NSCLC, unassociated with COX-2. Overexpression of mPGES-1 per se was not a prognostic indicator, but it might be implicated in the organ preference of metastasis.

Phase II trial of cisplatin, tegafur plus uracil and leucovorin as neoadjuvant chemotherapy in patients with squamous cell carcinoma of the oropharynx and hypopharynx

We evaluated the efficacy and toxicity of cisplatin, tegafur plus uracil and leucovorin as neoadjuvant chemotherapy for locally advanced squamous cell carcinoma (SCC) of the oropharynx and hypopharynx. Forty-six patients (stage IV, 83%; N2/3, 52%) were treated with PUL (50 mg/m2 cisplatin on day 1, 300 mg/m2 tegafur plus uracil orally and 60 mg leucovorin orally on days 1-14) over a 14-day cycle. Evaluation after 3 cycles led to chemotherapy termination if primary tumor responses were less than partial responses. Otherwise, PUL was continued up to 6 cycles before locoregional therapy. Patients achieving at least good partial responses at the primary site after neoadjuvant chemotherapy received radiotherapy for organ preservation. Chemotherapy responses were analyzed by intent-to-treat. Response rates of primary sites were 71.7% (33 of 46) with 34.8% (16 of 46) showing a complete response. Thirty patients (65.2%) achieved good partial responses at the primary site. Overall response and complete response rates of neck lymph nodes were 68.6% (24 of 35) and 25.7% (nine of 35). The combined response rate of primary site and neck lymph nodes was 63% (95% confidence interval 48.5-77.5%) with a complete response rate of 15.2%. Toxicities of WHO grade 3-4 included anemia (19.6%), diarrhea (17.4%) and neutropenia (8.7%). With a median follow-up of 36 months, overall survival and disease-free survival rates were 45.7% (21 of 46) and 41.3% (19 of 46); organ preservation rate was 90% (19 of 21). We concluded that the outpatient PUL regimen was a moderately effective, less-toxic neoadjuvant chemotherapy for SCC of the oropharynx and hypopharynx. PUL should be studied further with other active agents or radiotherapy.

Gastric bleeding due to graft-vs-host disease: discrepancy between endoscopic and histologic assessment

Gastric bleeding due to graft-vs-host-disease (GVHD) is rare after allogeneic hematopoietic stem cell transplantation, and the interrelationship between endoscopic and histologic assessment has not been well studied. Four patients with documented gastric bleeding due to GVHD were evaluated retrospectively. The endoscopic findings varied markedly and included mild mucosal edema with focal erythema, diffuse erythema with mucosal oozing, and diffuse polypoid indurations with multiple bleeding ulcerations. The histologic features of endoscopic biopsy specimens also varied from scattered apoptotic epithelial cells in one end to denudation of the epithelium with crypt necrosis in the other. The endoscopic findings could not accurately predict the histologic grading of GVHD. Nevertheless, gastric bleeding resolved in 3 patients with increasing intensity of immunosuppression. There was significant disparity between the endoscopic and histologic assessment of the severity of GVHD, and careful adjustment of immunosuppressive therapy might be warranted.

Fusidic acid-induced leukopenia and thrombocytopenia

Fusidic acid is an active agent against a wide variety of gram-positive bacteria, and it has been increasingly used in methicillin-resistant Staphylococcus aureus infection. The major adverse effects are mild gastrointestinal discomfort and diarrhea. The hematological side effects such as granulocytopenia and thrombocytopenia have been rarely reported in western countries, but have not been documented in Asian population. Between January and April 2001, we identified 2 cases of fusidic acid-induced leukopenia and thrombocytopenia after 2 weeks of fusidic acid treatment. In both cases, hematological abnormality resolved in 3 to 6 days after discontinuation of fusidic acid. The published literature regarding hematological adverse effects caused by fusidic acid is reviewed in this report, and an immune-mediated mechanism possibly by drug-dependent antibody is speculated. We recommend periodic complete blood count check in patients receiving long-term fusidic acid treatment to avoid serious hematological adverse effects.

Expression of Fas ligand in patients with evident skull base involvement of nasopharyngeal carcinoma

We investigated whether skull base involvement in patients with nasopharyngeal carcinoma (NPC) is correlated with expression of Fas ligand (FasL) in NPC cells. A prospective assessment of FasL expression was determined by immunohistochemistry and in situ hybridization in 98 patients with newly diagnosed NPC. Among these patients, 21 had evident skull base involvement. Expressions of human apoptosis-related genes and FasL were confirmed by reverse transcription-polymerase chain reaction. Relation between the frequency of skull base involvement and FasL expression was analyzed by Chi-square and multivariate analyses. FasL expression was detected in 32 (32.6%) of 98 pathological sections. Compared to patients with low FasL expression in tumors, patients with notable FasL expression had higher incidence of skull base involvement (28.6 vs. 71.4%, p<0.005). Expression of FasL in tumor cells was correlated with the higher frequency of skull base involvement in patients with NPC.

UCN-01 suppresses E2F-1 mediated by ubiquitin-proteasome-dependent degradation

E2F-1 regulates the transcription of genes required for DNA synthesis. Previously, we have reported that UCN-01 suppresses E2F-1 protein expression without any noticeable effect on its mRNA level in gastric cancer cell line SK-GT5 (Clin. Cancer Res., 4: 2201-2206, 1998). In this study, we investigated the mechanism responsible for the suppression of E2F-1 expression by UCN-01 in SK-GT5 cells. After 24-h exposure to 1 microM UCN-01, E2F-1 protein expression was decreased by >99%. The suppressive effect of UCN-01 could be reversed by ubiquitin-dependent proteasome inhibitors such as calpain inhibitor I and lactacystin. Transfection experiments using expression plasmids encoding full-length E2F-1 or truncated E2F-1 with deletion of the COOH-terminal region (which is required for eliciting ubiquitination and protein degradation) revealed that the expression of truncated E2F-1 was not affected by UCN-01. Other cell-cycle-related and ubiquitin-proteasome-regulated proteins such as p21, p27, and cyclin B1 were not repressed by UCN-01 in E2F-1-overexpressing cells. In vitro-translated, full-length E2F-1 degraded more rapidly upon incubation with extracts from UCN-01-treated cells when compared with truncated E2F-1. Taken together, these data indicate that UCN-01 suppresses E2F-1 protein expression mediated by the ubiquitin-proteasome pathway in a specific manner.

Selective inhibition of cyclooxygenase-2 enhances mitomycin-C-induced apoptosis

PURPOSE

Cyclooxygenase-2 (COX-2) is involved in antiapoptosis signaling, and its induction may require activation of protein kinase C (PKC). Safingol (SAF), a PKC inhibitor, has been shown to enhance apoptosis induced by mitomycin-C (MMC) in human gastric cancer MKN-74 cells. The aim of this study was to identify the role of COX-2 in MMC-induced apoptosis in MKN-74 cells.

METHODS

Protein expression of COX-2 and Bcl-2 and activation of PKCalpha were examined by Western blot analysis. Apoptosis induction was examined by staining with bisbenzimide trihydrochloride (Hoechst-33258) of condensed chromatin, which characterizes the cells undergoing apoptosis. COX-2 mRNA levels were examined by Northern blot analysis.

RESULTS

After exposure for 1-2 h to 1 microg/ml MMC, upregulation of COX-2 and Bcl-2 protein expression was noted. The activation of PKCalpha occurred within 1 h of MMC exposure, and temporally preceded the induction of COX-2. Similar results were observed in cells exposed to the PKC activator, 3-phorbol 12-myristate 13-acetate. Cotreatment with SAF and MMC abolished the induction of COX-2 by MMC. Furthermore, NS-398, a selective COX-2 inhibitor, significantly enhanced MMC-induced apoptosis by fivefold from 4 +/- 2% (MMC alone) to 20 +/- 2% (MMC plus NS-398). There was no discernible change in COX-2 mRNA levels after a 2-h exposure to MMC but a twofold increase after a 24-h exposure.

CONCLUSIONS

MMC upregulates COX-2 expression, which appears to be an antiapoptotic signal downstream of PKC. Selective inhibition of COX-2 can therefore provide a novel way to enhance MMC-induced apoptosis independent of inhibiting PKC.

UCN-01 suppresses thymidylate synthase gene expression and enhances 5-fluorouracil-induced apoptosis in a sequence-dependent manner

UCN-01, a protein kinase C/cyclin-dependent kinase inhibitor, suppressed thymidylate synthase (TS) protein expression in a dose-dependent manner with near complete suppression at 1 microM after a 24-h exposure in human gastric cancer cell line SK-GT5. Other protein kinase C/cyclin-dependent kinase inhibitors, including flavopiridol and safingol, had a similar effect on TS protein expression, but to a lesser degree. Moreover, UCN-01 repressed the induction of TS after 5-fluorouracil (FU) exposure by 90-95% and significantly enhanced the induction of apoptosis by FU from 4-8% with either FU or UCN-01 alone to 46+/-1% (P < 0.005 versus either single drug, reverse sequence, or the combination) when UCN-01 was given after FU. The effect of UCN-01 on TS was associated with a dose-dependent suppression of the E2F-1 protein, a transcriptional activator of TS. Northern blot analysis revealed that TS mRNA levels decreased gradually as the concentration of UCN-01 increased, but that E2F-1 mRNA levels remained relatively unchanged. UCN-01 may provide a novel way to enhance cellular sensitivity toward FU by means of suppressing TS expression mediated mainly by down-regulation of E2F-1.

rTS gene expression is associated with altered cell sensitivity to thymidylate synthase inhibitors

rTS is a recently discovered gene, phylogenetically conserved and found to be expressed in a wide variety of cell lines. rTS has also been found to be overexpressed in two cell lines resistant to FU and to MTX. The MTX-resistant cell line was found to have a high degree of cross resistance to several TS inhibitors. An apparent paradox to this correlation of rTS overexpression and resistance to TS inhibitors is the observation that expression of transfected rTS alpha results in enhanced sensitivity of cells to the TS inhibitor prodrug TFT and a modest increase in resistance to FUdR. Since immunoprecipitation of TS leads to the co-immunoprecipitation of two proteins within the expected molecular weight range of the two rTS proteins, it may be that both proteins bind to TS in vivo and modify its activity. Preliminary data substantiate this conclusion. It is conceivable that the ratio of the two rTS proteins associated with TS in vivo may differentially alter TS activity depending upon their stoichiometry or possibly posttranslational modification. Thus it may be possible for rTS to confer greater sensitivity to one pyrimidine analog (e.g., TFT) which is a product analog but to increase resistance or have a minor effect on a substrate analog (e.g., FdUMP) by stabilizing different conformations of TS. The structure of the rTS proteins suggests they are expected to have catalytic activity which involves proton abstraction from an alpha-carbon of a carboxyl group. Whether this enzyme activity is functional and related to pyrimidine metabolism awaits further study.

Regulation of folate-binding protein gene expression by DNA methylation in methotrexate-resistant KB cells

Folate-binding protein (FBP) is responsible for the cellular transport of folate and methotrexate (MTX) in human KB (nasopharyngeal epidermoid carcinoma) cells. The levels of membrane-associated FBP and FBP mRNA are decreased 70-80% in an MTX-resistant KB subline (KB1BT) (Hsueh C-T and Dolnick BJ, Oncol Res 4: 497-505, 1992). Southern blot analysis did not reveal any differences in FBP gene organization or copy number between KB1BT and KB cells. However, there was a 70% decrease in the FBP gene transcription rate and no change in FBP mRNA stability in KB1BT cells. Assessing genomic DNA methylation by MspI and HpaII restriction analysis suggested that the FBP gene in KB1BT cells was more methylated than in KB cells. These alterations in the expression, transcription rate and DNA methylation state of the FBP gene did not change when KB1BT cells were grown in the absence of MTX for 8 months (MTX-free KB1BT). When MTX-free KB1BT cells were exposed to 2.5 microM 5-aza-2'-deoxycytidine for 72 hr, the FBP gene became hypomethylated and the levels of membrane-associated FBP and FBP mRNA increased by 2- to 3-fold. These data indicate that decreased FBP gene expression in KB1BT cells results from increased DNA methylation.

Altered folate-binding protein mRNA stability in KB cells grown in folate-deficient medium

Folate-binding protein (FBP), a high-affinity folate receptor, is responsible for cellular accumulation of folate and folate analogs such as methotrexate in human KB (nasopharyngeal carcinoma) cells. Both FBP and FBP mRNA increase 3- to 5-fold when KB cells are grown in folate-deficient (less than 10 nM folate) medium (KB-FD), compared with growth in standard folate-replete medium containing at least 2 microM folate (KB-FR). The possible mechanisms of enhanced FBP gene expression in KB-FD were examined in this study. Southern blot analysis revealed no significant change in the FBP gene organization or copy number in the KB-FD DNA. While hypomethylation of the FBP gene was observed in KB-FD DNA, relative to KB-FR DNA, exposure of KB-FR to the DNA methylation inhibitors did not result in elevated FBP mRNA levels. The transcriptional rate of the FBP gene was the same in KB-FR and KB-FD. RNA half-life studies indicated that the half-life of FBP mRNA in KB-FD was increased approximately 2.5-fold, compared with KB-FR. Thus, the increase in the steady-state levels of FBP mRNA in KB-FD can be attributed partly to increased FBP mRNA stability.

Augmentation of the immune response of the murine liver by levamisole

Murine hepatic nonparenchymal cells (NPC) were studied following in vivo treatment with levamisole. This agent was found to increase the cytolytic action of these cells against YAC-1 and P815 target cells. An increase in the cytostatic activity against liver-derived murine colon adenocarcinoma 38 tumor cells was also observed. Treatment with levamisole also augmented the proliferation of the hepatic NPC. Supernatants generated by these cells contained an agent capable of stimulating the proliferation of bone marrow cells from the same mice. The effect of levamisole on different subsets of NPC derived from the liver in this model is discussed.

Genetic analysis of the nitrogen fixation system in Klebsiella pneumoniae

Fine structure mapping of nif mutations of Klebsiella pneumoniae was accomplished by means of Pl-transductional crosses and the plasmid R144 drd mediated conjugations. The physical distance between nif mutations based on the percentage of co-transduction with hisD of the nif mutations was estimated. The maximal distance between two mutations was calculated about 3 Kb, and the average distance between different nif mutations was about 1 to 2 Kb. So no "silent region" was shown within the nif cluster nearby the histidine operon. Several hisD-unlinked nif mutants were isolated and investigated genetically and biochemically. They all differed from the glutamineless mutants, one of these mutants was tentatively assigned as a sort of N-assimilation mutant with little activity of glutamate synthetase. It differed from the known N-assimilation mutants in its absence of nitrogenase activity. Since the wild type hisD-linked nif genes carried by the plasmid RP4 failed to complement the defects of the hisD-unlinked nif genes in the recipient cells but they were effective to facilitate E. coli in acquiring the ability to fix nitrogen, which indicates that the hisD-unlinked nif genes necessary for the functioning of the hisD-linked nif genes are present in E. coli.