Management of bevacizumab-associated bowel perforation: a case series and review of the literature

BACKGROUND

This study examined the various approaches to the management of perforation and the associated outcomes in patients with bevacizumab-associated bowel perforation at a tertiary cancer center.

PATIENTS AND METHODS

Our institutional pharmacy database was searched to identify all patients who had received bevacizumab over a 2-year period (January 2004 to October 2006). Medical records of these patients were examined for reports of confirmed bowel perforation or fistula, associated clinicopathological factors, treatment, and outcomes.

RESULTS

We identified 1442 patients who had been treated with bevacizumab over the study period with perforation occurring in 24 (1.7%). The breakdown of these 24 patients by disease site was as follows: ovarian (3 of 50, 6%), gastroesophageal (2 of 38, 5.3%), pancreatic (7 of 141, 5%), unknown primary (1 of 60, 1.7%), lung (1 of 67, 1.5%), colorectal (6 of 478, 1.3%), and renal cell (4 of 269, 1.5%). The majority of patients (n = 19, 79%) were initially managed nonoperatively. Only five (21%) patients ultimately underwent surgical exploration, with a subsequent anastomotic leak developing in one patient. The overall 30-day mortality rate was 12.5%.

CONCLUSIONS

Bevacizumab-associated bowel perforation occurs in patients with various malignancies, with an incidence of 1.7%. Nonoperative treatment is a viable approach to management in selected patients.

Long-term maintenance capecitabine and celecoxib improved clinical outcomes by targeting colorectal cancer micrometastasis

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Background: Role of mainteance therapy after achieving complete response (CR) remain undefined for patients with metasatic colorectal cancer. We studied prognostic and treatment factors including maintenance capecitabine and celecoxib (XCEL) in all 19 unresectable metastatic colorectal cancer patients (pts) who had CR from the prior XCEL study. Methods: Event charts are used to summarize the timeline of the various treatments. Kaplan-Meier survival estimates and univariate log-rank tests were used to evaluate RFS and OS as time from CR. Prognostic and treatment factors included: tumor size, metastasis number (9 solitary disease), site (13 being extrahepatic), stage on diagnosis (stage II versus III/IV), disease free interval prior to stage IV disease, surgery (5 R0, 3 R1–2 resections), lactate dehydrogenase levels, first-line irinotecan chemotherapy, radiation (9 pts ≥ 45 Gy, 3 Pts < 45 Gy), and maintenance XCEL (duration 0–50.3 months). Results: Nine of 19 patients experienced recurrence (median 13 months after CR), and 4 died during the follow-up period (median 31 months after CR). The 2-year RFS for the unresected and R1–2 resected patients was 71% versus 20% for the R0 resected patients (p = 0.07). This paradoxical RFS pattern corresponded to a RFS advantage for maintenance XCEL (p = 0.002), but not any other prognostic or treatment factors. All relapses occurred in situ following discontinuation of XCEL except for the surgical cases. Patients undergoing maintenance XCEL also benefited in OS (p = 0.04). The median OS from XCEL and from onset of metastasis reached 51.9 months (95% CI, 45 months- not reached [NR]) and 73.3 months (95% CI, NR-NR months) respectively. Conclusions: Maintenance XCEL targets colorectal micrometastases and produces a paradoxical RFS and OS advantage among the high-risk unresected/R1–2 resected patients than R0 resected patients. Prospective studies are warranted to validate roles of maintenance XCEL in the treatment of colorectal micrometastases.

No significant financial relationships to disclose.

Paclitaxel-based chemoradiotherapy in localized gastric carcinoma: degree of pathologic response and not clinical parameters dictated patient outcome

PURPOSE

Preoperative chemoradiotherapy may increase the R0 (curative) resection rate, overall survival (OS) duration, and disease-free survival (DFS) duration. We evaluated paclitaxel-based induction chemotherapy and chemoradiotherapy in patients with localized gastric or gastroesophageal adenocarcinoma to determine its feasibility, impact on the R0 resection rate, type of pathologic response, OS, and DFS.

PATIENTS AND METHODS

Patients with operable, localized gastric, or gastroesophageal adenocarcinoma were eligible. Staging included endoscopic ultrasonography (EUS) and laparoscopy. Patients received two 28-day cycles of induction chemotherapy of fluorouracil, paclitaxel, and cisplatin followed by 45 Gy of radiation and concurrent fluorouracil plus paclitaxel. The cancer was restaged and surgery was attempted. Postsurgery pathologic findings and R0 resection were correlated with OS and DFS.

RESULTS

Forty-one patients were enrolled. Most carcinomas were proximal (83%) and pretreatment stage EUST3 (85%). Forty patients (98%) underwent surgery, and 78% had an R0 resection. We observed a pathologic complete response (pathCR) rate of 20% and a pathologic partial response (pathPR) rate of 15% (< 10% residual cancer cells in the resected specimen). No pretreatment parameter (sex, cancer location, baseline T stage, or baseline N stage) predicted the type of postsurgery pathologic response, OS, or DFS. However, pathCR (P = .02), pathCR + pathPR (P = .006), R0 resection (P < .001), and postsurgery T and N stages (P = .01 and P < .001, respectively) were associated with OS. Same parameters were significantly correlated with DFS. Toxicity was manageable.

CONCLUSION

The type of pathologic response but not pretreatment parameters was associated with OS and DFS. Efforts to increase the rate of pathologic response and better systemic cancer control are warranted.

Multi-institutional trial of preoperative chemoradiotherapy in patients with potentially resectable gastric carcinoma

PURPOSE

In the West, curative (R0) resection is achieved in approximately 50% of patients with localized gastric carcinoma, and more than 60% die of cancer following an R0 resection. A multi-institutional study of preoperative chemoradiotherapy was done to assess the R0 resection rate, pathologic complete response (pathCR) rate, safety, and survival in patients with resectable gastric carcinoma.

PATIENTS AND METHODS

Operable patients with localized gastric adenocarcinoma were eligible. Staging also included a laparoscopy and endoscopic ultrasonography (EUS). Patients received up to two 28-day cycles of induction chemotherapy of fluorouracil, leucovorin, and cisplatin, followed by 45 Gy of radiation plus concurrent fluorouracil. Patients were then staged and surgery was attempted.

RESULTS

Thirty-four patients were registered at three institutions. One ineligible patient was excluded. Most patients had a promixal cancer and EUST3N1 designation. Twenty-eight (85%) of 33 patients underwent surgery. The R0 resection rate was 70% and pathCR rate was 30%. A pathologic partial response (< 10% residual carcinoma in the primary) occurred in eight patients (24%). EUS T plus N and postsurgery T plus N correlation showed significant downstaging (P = <.01). The median survival time for 33 patients was 33.7 months. Patients achieving a pathCR or pathPR had a significantly longer median survival time (63.9 months) than those achieving less than pathPR (12.6 months; P =.03). There were two treatment-related deaths.

CONCLUSION

Our data suggest that the three-step strategy of preoperative induction chemotherapy followed by chemoradiotherapy resulted in substantial pathologic response that resulted in durable survival time. This strategy is worthy of a direct comparison with postoperative adjuvant chemoradiotherapy.

Multi-institutional trial of preoperative chemoradiotherapy in patients with potentially resectable gastric carcinoma

PURPOSE

In the West, curative (R0) resection is achieved in approximately 50% of patients with localized gastric carcinoma, and more than 60% die of cancer following an R0 resection. A multi-institutional study of preoperative chemoradiotherapy was done to assess the R0 resection rate, pathologic complete response (pathCR) rate, safety, and survival in patients with resectable gastric carcinoma.

PATIENTS AND METHODS

Operable patients with localized gastric adenocarcinoma were eligible. Staging also included a laparoscopy and endoscopic ultrasonography (EUS). Patients received up to two 28-day cycles of induction chemotherapy of fluorouracil, leucovorin, and cisplatin, followed by 45 Gy of radiation plus concurrent fluorouracil. Patients were then staged and surgery was attempted.

RESULTS

Thirty-four patients were registered at three institutions. One ineligible patient was excluded. Most patients had a promixal cancer and EUST3N1 designation. Twenty-eight (85%) of 33 patients underwent surgery. The R0 resection rate was 70% and pathCR rate was 30%. A pathologic partial response (< 10% residual carcinoma in the primary) occurred in eight patients (24%). EUS T plus N and postsurgery T plus N correlation showed significant downstaging (P = <.01). The median survival time for 33 patients was 33.7 months. Patients achieving a pathCR or pathPR had a significantly longer median survival time (63.9 months) than those achieving less than pathPR (12.6 months; P =.03). There were two treatment-related deaths.

CONCLUSION

Our data suggest that the three-step strategy of preoperative induction chemotherapy followed by chemoradiotherapy resulted in substantial pathologic response that resulted in durable survival time. This strategy is worthy of a direct comparison with postoperative adjuvant chemoradiotherapy.

Phase I clinical and pharmacological study of intraperitoneal cis-bis-neodecanoato( trans- R, R-1, 2-diaminocyclohexane)-platinum II entrapped in multilamellar liposome vesicles

PURPOSE

To perform a phase I study of intraperitoneal cis-bis-neodecanoato ( trans- R, R-1, 2-diaminocyclohexane)-platinum II entrapped in multilamellar vesicles (L-NDDP) for peritoneal carcinomatosis or sarcomatosis.

METHODS

Eligible patients had normal renal, hematologic, and liver functions. Laparoscopy was performed on the first two courses for evaluation, adhesiolysis, and chemotherapy administration. Afterwards, chemotherapy was administered through a peritoneal catheter. Up to six courses were allowed. Peritoneal imaging with technetium-labeled sulfur colloid was used to determine adequate distribution prior to each course. Volunteering patients underwent pharmacokinetics studies during the second course.

RESULTS

Fifteen of 16 registered patients, seven women and eight men (median age 53 years (range 26-76) and median performance status of 1) were assessable. Diagnoses were: malignant mesothelioma (six patients), signet ring cell (three), colon adenocarcinoma, pseudomyxoma peritonei, gastrointestinal stromal tumor (two each), and ovarian carcinoma (one). Median number of courses was two (range, one to six) Dose-limiting toxicity symptoms were fatigue and abdominal pain. Hematologic toxicities were minimal. Peri-operative complications included one colonic perforation requiring primary closure, a peritoneal catheter malfunction, a port site hematoma, and an ascites leak requiring re-suture. Five patients survived at least 3 years. Pharmacokinetics studies indicated a rapid but low absorption of drug into the systemic circulation, with a prolonged retention of platinum in the plasma compartment. Peritoneal L-NDDP exposure was 17 to 49-times greater than in the plasma compartment.

CONCLUSIONS

Peritoneal cavity exposure to L-NDDP is prolonged, and systemic absorption is limited, yielding a high peritoneal/plasmatic ratio. The recommended dose for phase II studies is 400 mg/m2 every 28 days.

Elective groin irradiation is not indicated for patients with adenocarcinoma of the rectum extending to the anal canal

PURPOSE

To evaluate the inguinal nodal failure rate in patients with locally advanced rectal cancer with anal canal involvement (ACI) treated with pelvic chemoradiation without elective inguinal irradiation.

METHODS AND MATERIALS

From 1990 and 1998, 536 patients received preoperative or postoperative chemoradiation for rectal cancer with curative intent; 186 patients had ACI (<4 cm from the anal verge on rigid proctoscopy). Two patients had positive inguinal nodes at presentation. Chemoradiation was delivered preoperatively (45 Gy in 25 fraction) or postoperatively (53 Gy in 29 fractions) with concurrent continuous infusion of 5-fluorouracil (300 mg/m2/d). The inguinal region was specifically irradiated in only 2 patients who had documented inguinal nodal disease.

RESULTS

The median follow-up was 50 months. Only 6 of 184 ACI patients who had clinically negative inguinal nodes at presentation developed inguinal nodal recurrence (5-year actuarial rate 4%); 4 of the 6 cases were isolated. Two patients underwent successful salvage. Only 1 died of uncontrolled groin disease. Local control was achieved in both patients with inguinal nodal disease at presentation, but both died of metastatic disease. Only 3 patients with tumors >4 cm from the verge developed inguinal recurrence (5-year actuarial rate <1%).

CONCLUSIONS

Inguinal nodal failure in rectal cancer patients with ACI treated with neoadjuvant or adjuvant chemoradiation is not high enough to justify routine elective groin irradiation.

Utility of breast sentinel lymph node biopsy using day-before-surgery injection of high-dose 99mTc-labeled sulfur colloid

BACKGROUND

In sentinel lymph node (SLN) biopsy for breast cancer, many centers use same-day preoperative injection of technetium 99mTc-labeled sulfur colloid and intraoperative injection of blue dye for localization of SLNs. Same-day sulfur colloid injections can be problematic because of the variability in sulfur colloid migration times, which can lead to ineffective use of operating room time, and low SLN-to-background radioactivity ratios. We examined the utility of day-before-surgery injections of high dose 99mTc-labeled sulfur colloid injections.

METHODS

The day before surgery, high-dose 99mTc-labeled sulfur colloid was injected peritumorally, and a lymphoscintigram was obtained. Intraoperatively, after injection of blue dye, a gamma probe was used to localize SLNs. Nodes that were stained blue or were highly radioactive were considered SLNs and were removed.

RESULTS

Lymphoscintigraphy demonstrated drainage in 107 patients (91%). Transcutaneous localization of the SLN was possible in 104 patients (89%). In three patients, all of whom had no drainage demonstrated on lymphoscintigraphy, no SLN was identified at surgery (97.5% success rate for SLN identification). A mean of 2.3 SLNs per patient were identified. Twenty-five patients (21%) had at least one histologically positive SLN. In 23 of these patients, the positive SLN was the SLN with the most radioactivity, and in the remaining two patients, the positive SLN was both blue-stained and hot.

CONCLUSION

Day-before-surgery injection of high-dose 99mTc-labeled sulfur colloid results in high rates of transcutaneous and intraoperative identification of SLNs. The delay between injection and surgery did not appear to promote significant passage of sulfur colloid to second-echelon nodes.

Elective groin irradiation is not indicated for patients with adenocarcinoma of the rectum extending to the anal canal

PURPOSE

To evaluate the inguinal nodal failure rate in patients with locally advanced rectal cancer with anal canal involvement (ACI) treated with pelvic chemoradiation without elective inguinal irradiation.

METHODS AND MATERIALS

From 1990 and 1998, 536 patients received preoperative or postoperative chemoradiation for rectal cancer with curative intent; 186 patients had ACI (<4 cm from the anal verge on rigid proctoscopy). Two patients had positive inguinal nodes at presentation. Chemoradiation was delivered preoperatively (45 Gy in 25 fraction) or postoperatively (53 Gy in 29 fractions) with concurrent continuous infusion of 5-fluorouracil (300 mg/m2/d). The inguinal region was specifically irradiated in only 2 patients who had documented inguinal nodal disease.

RESULTS

The median follow-up was 50 months. Only 6 of 184 ACI patients who had clinically negative inguinal nodes at presentation developed inguinal nodal recurrence (5-year actuarial rate 4%); 4 of the 6 cases were isolated. Two patients underwent successful salvage. Only 1 died of uncontrolled groin disease. Local control was achieved in both patients with inguinal nodal disease at presentation, but both died of metastatic disease. Only 3 patients with tumors >4 cm from the verge developed inguinal recurrence (5-year actuarial rate <1%).

CONCLUSIONS

Inguinal nodal failure in rectal cancer patients with ACI treated with neoadjuvant or adjuvant chemoradiation is not high enough to justify routine elective groin irradiation.

T4 rectal cancer treated with preoperative chemoradiation to the posterior pelvis followed by multivisceral resection: patterns of failure and limitations of treatment

PURPOSE

To analyze the overall pattern of treatment failure and sites of pelvic disease recurrence relative to the radiation fields used in treating patients with clinically staged T4 rectal cancer with preoperative chemoradiation followed by multivisceral resection.

METHODS AND MATERIALS

Between 1990 and 1998, 45 patients with T4 rectal cancer were treated with preoperative chemoradiation. Clinical staging was according to the system of the American Joint Cancer Committee and was based on endoscopic ultrasonography, chemotherapy (CT), and physical examination. A diagnosis of T4 disease required evidence of invasion of a contiguous structure on CT (n = 31) or endorectal ultrasonography (n = 6), vaginal mucosal involvement on pelvic examination (n = 6), or a combination of these findings (n = 2). Chemoradiation was delivered with 18 MV photons using a 3-field belly-board technique. The median total dose was 45 Gy in all patients (range 45-63). Nine patients received a boost with external beam radiotherapy (EBRT) (n = 5, 1.8-18 Gy), intraoperative RT (n = 3, 10-20 Gy), or interstitial brachytherapy (n = 1, 20 Gy). All patients received concurrent chemotherapy consisting of protracted venous infusion 5-fluorouracil (300 mg/m(2), 5 d/wk). Resection was not performed in 13 (29%) of the 45 patients because of metastases detected before resection or patient refusal. Multivisceral resection and pelvic exenteration was required in 21 (66%) and 11 (34%) of 32 patients, respectively. We compared the location of pelvic disease recurrence with the RT simulation films. The Kaplan-Meier method was used to calculate the 4-year actuarial pelvic and distant recurrent rates and the overall survival rate.

RESULTS

The median length of follow-up was 31.0 months for all patients and 40.0 months for patients alive at last follow-up. When only the resected cases were considered, the local recurrence rate was 20%. Distant metastases occurred in 44% of cases; the overall survival rate was 69%. When all patients were considered, the local recurrence rate was similar (24%), but the rate of distant recurrence (51%) was higher and the overall survival rate lower (50%). Pelvic disease was controlled in all 8 patients whose disease responded well to chemoradiation (either a histologically complete response or microscopic residual disease). Three of 4 patients with close or positive margins had pelvic recurrences despite intraoperative RT and brachytherapy. Nine of the 10 pelvic recurrences occurred in the radiation field. Elective external iliac nodal irradiation was not used, and nodal metastases were not seen in that region. In 1 case, marginal recurrence occurred in a common iliac node at the superior edge of the treatment field.

CONCLUSIONS

Despite aggressive multimodality therapy including multivisceral resection, a high rate of pelvic and distant disease recurrence occurred in patients with clinically staged T4 disease. Regional disease recurred almost exclusively in the radiation field. The intraoperative RT and interstitial brachytherapy doses used did not prevent pelvic disease recurrence in patients with close or positive margins. Novel strategies such as higher preoperative doses of RT with or without altered fractionation or more effective radiosensitizers are needed to improve locoregional control in patients with T4 disease. Future strategies must also include more effective systemic therapy.

Irinotecan plus cisplatin in advanced gastric or gastroesophageal junction carcinoma

A phase II study was conducted to assess the response rate and toxicity profile of the combination of irinotecan (CPT-11, Camptosar) and cisplatin (Platinol) administered weekly to patients with untreated advanced adeno-carcinoma of the stomach or gastroesophageal junction. Patients with histologic proof of adenocarcinoma of the stomach or gastroesophageal junction and with adequate liver, kidney, and bone marrow functions were included. Patients were treated with 65 mg/m2 of irinotecan plus 30 mg/m2 of cisplatin, both administered intravenously 1 day per week for 4 consecutive weeks, followed by a 2-week recovery period. Response rate, time to progression, survival, and toxic effects were analyzed. Thirty-six (95%) of 38 registered patients were assessable for toxicity and response. The median number of 6-week cycles per patient was 2.5 (range: 1 to 7 cycles). Four patients (11%) achieved a complete response and 17 (47%) had a partial response for an overall response rate of 58%. Median time to progression of carcinoma was 24 weeks, and median survival was 9 months (range: 1 to 23+ months). There was one treatment-related death. Major toxic effects included diarrhea, neutropenia, and fatigue. The combination of irinotecan and cisplatin is active against gastric or gastroesophageal adenocarcinoma and should undergo further study. The addition of other active drugs or radiation therapy to this regimen would be of interest.

Adenovirus-mediated p53 gene therapy inhibits human sarcoma tumorigenicity

Mutations of the p53 tumor-suppressor gene are the most frequent genetic abnormality in soft tissue sarcomas. Because these rare tumors also respond poorly to standard chemotherapy and bear a 50% 5-year mortality rate, we investigated the possible therapeutic benefits of p53 gene restoration in sarcomas. We constructed Ad5p53, which is an E1A-deleted, replication-deficient adenovirus expressing a cytomegalovirus promoter-driven wild-type p53 cDNA with a Flag sequence tag. SKLMS-1 human leiomyosarcoma cells containing a mis-sense p53 point mutation were effectively transduced with Ad5p53. Increasing levels of Flag-p53 protein, as well as dose-dependent p21Cip1 induction, were observed through a dose range of 10-500 plaque-forming units (PFU)/cell. In vitro administration of Ad5p53 as a single 100 PFU/cell dose caused 40-60% growth inhibition of SKLMS-1 cells at posttreatment days 4, 6, and 8 compared with untreated or viral control treated-cells (P < .05, Student's t test). Relative to these same controls, in vivo treatment of SKLMS-1-bearing severe combined immunodeficient mice with 6 x 10(9) PFU of Ad5p53 by intratumoral injection resulted in a 35-day tumor growth delay and complete tumor regression in 40% of mice (P < .05, Student's t test). The expression of virally derived p53 mRNA in Ad5p53-treated tumor tissues was detected in treated tumor specimens by reverse transcriptase polymerase chain reaction. Reduced intratumoral cellularity and the presence of p53 staining in adjacent normal tissue, consistent with delivery of exogenous p53 to the tumor target, were evident only in Ad5p53-treated tumors after immunohistochemical staining for p53. These results indicate that wild-type p53 gene restoration in sarcomas retards tumor growth and may come to be usefully applied to the clinical treatment of this disease as a single regimen or in combination with conventional therapies.

Enhanced staging and all chemotherapy preoperatively in patients with potentially resectable gastric carcinoma

PURPOSE

Patients with local-regional gastric carcinoma have a low rate of curative resection (R0) because of the advanced stage at diagnosis and suboptimal clinical staging. This study was designed to improve clinical staging with the use of laparoscopy and endoscopic ultrasonography (EUS) and to improve R0 resection rates and tolerance by delivering all chemotherapy preoperatively in patients with potentially resectable gastric carcinoma.

PATIENTS AND METHODS

All patients with histologic proof of localized adenocarcinoma of the stomach underwent a staging laparoscopy before registration. EUS was performed when feasible. The intention was to administer up to five courses of preoperative chemotherapy consisting of fluorouracil (500 mg/m(2)/d as a continuous infusion on days 1 through 5 and as a bolus on days 12 and 19), interferon alfa-2b (3 million units subcutaneously three times a week for 3 weeks), and cisplatin (15 mg/m(2)/d as a bolus on days 1 through 5). After chemotherapy, surgery was attempted to remove the primary and regional lymph nodes. Clinical response and EUS staging were correlated with surgical pathology. The feasibility of this approach, resection rates, patient survival, and patterns of failure also were assessed.

RESULTS

All 30 patients enrolled were assessed for toxicity, response, and survival. Nineteen men and 11 women were enrolled. The median number of courses delivered per patient was three (range, one to five courses). Fourteen patients (47%) received all five preoperative courses of chemotherapy. The overall clinical response rate was 34%. Twenty-nine patients (97%) underwent attempted resection. Twenty-five (83%) had an R0 resection. Two patients (7%) had no evidence of carcinoma in the surgical specimen, and three had only microscopic carcinoma (>/= 90% necrosis). Posttreatment EUS findings did not correlate well with surgical pathology. The median duration of follow-up was 30 months (range, 5 months to 65+ months). The median survival time for 30 patients, calculated by the Kaplan-Meier method, was 30 months (range, 5 months to 65+ months). There were no cases of grade 4 toxicity.

CONCLUSION

It is feasible to administer prolonged preoperative therapy in patients with potentially resectable gastric carcinoma. Enhanced staging with laparoscopy and EUS helped in proper selection of patients and better characterization of the stage.

Cytotoxic effects of sphingolipids as single or multi-modality agents on human melanoma and soft tissue sarcoma in vitro

We evaluated the cytotoxic effects of a cell-permeable ceramide (Cer), N-hexanoyl-D-sphingosine (C6-Cer) and of two related sphingoid bases, sphingosine (So) and dihydrosphingosine (sphinganine; Sa) on human melanoma cell lines and on soft tissue sarcoma lines recently established from fresh surgical biopsy specimens. These cell lines ranged from high susceptibility (939 melanoma) to strong resistance (A2058 melanoma and all three sarcomas) to tumour necrosis factor (TNF), an inducer of elevated intracellular Cer levels. However, all the cell lines demonstrated a dose-dependent susceptibility to C6-Cer with protracted cytotoxic kinetics, with the C8161 melanoma being the most sensitive and A2058 the least. Protein kinase C (PKC) antagonizes Cer-dependent apoptosis, and chelerythrine chloride, So and Sa, which inhibit PKC, caused extremely rapid cytotoxicity of melanoma cell lines, irrespective of their relative sensitivity to C6-Cer. So-mediated cytotoxicity was extensive even after only 90 min of treatment, within the time frame of limb perfusion. So and Sa only slightly potentiated the cytotoxic responses to TNF, C6-Cer or melphalan. Sphingolipid-driven intracellular pathways may offer opportunities for therapy of these tumours.

Isolated limb perfusion in the sarcoma-bearing rat: a novel preclinical gene delivery system

Reliable site-specific delivery of genetic constructs remains a challenging component of gene-based therapy of solid tumors. Isolated limb perfusion (ILP) continues to be evaluated for treatment of locally advanced soft tissue sarcomas because this approach uniquely directs therapeutic agents into the tumor-bearing extremity without significant systemic leak. In light of these considerations, we tested the hypothesis that ILP could be used to deliver genes carried in viral vectors to the sarcoma-bearing rat extremity, resulting in demonstrable gene transfer into the tumor. ILP was performed in rats by cannulating the femoral artery and vein, isolating the hind limb from systemic circulation by tourniquet, and cycling perfusate for 15 min at a rate of 2.4 ml/min. Leakage into the systemic circulation was 7.5% of the total perfusate concentrated in the isolated limb, as determined by perfusion with technetium 99m-tagged RBCs. We used the ILP technique to perfuse rat hind limbs bearing syngeneic fibrosarcoma tumor nodules with the replication-defective adenovirus Ad5LacZ, which expresses the bacterial beta-galactosidase. 5-Bromo-4-chloro-3-indolyl-beta-D-galactoside staining of the perfused limb tissues confirmed gene transfer to the tumor and peritumoral tissue, demonstrating that the tumor was part of the perfusion circuit and that gene therapy delivered via this method was feasible. These results suggest that adaptation of this preclinical gene delivery model to administer genetic constructs aimed at controlling tumor growth may prove beneficial to patients with extremity sarcomas.

Effect of fetal bovine serum glycoproteins on the in vitro proliferation of the oyster parasite Perkinsus marinus: development of a fully defined medium

The oyster parasite Perkinsus marinus replicates in our medium consisting of Dulbecco modified Eagle's medium: Ham's F12 nutrient mixture (1:1) supplemented with 1-5% fetal bovine serum, with a doubling time of 24 hours during the exponential phase of the culture. Fetal bovine serum concentrations above 5% dramatically reduced parasite proliferation in a dose-dependent manner. We tested the individual effects of the three major protein components of fetal bovine serum (fetuin, transferrin and albumin) on the replication of the parasite in a serum-free medium. At the concentrations tested, fetuin enhanced parasite growth, whereas albumin had a modest positive effect and transferrin was inhibitory. Proteolytic digestion of fetuin, strongly diminished its growth-enhancing properties, indicating that the overall glycoprotein architecture may be required for activity. On the contrary, desialylation of fetuin slightly enhanced its growth-promoting activity. The addition of fetuin at 1.7 mg/ml to the serum-free DME:Ham's F12 medium yielded growth rates that are comparable to those obtained with our standard culture methodology. This has resulted in a fully defined culture medium that will allow for a rigorous characterization of excretory/secretory products involved in modulating or blocking the host's humoral and cellular defense mechanisms.

Tetramodality treatment of human melanoma in vitro

We evaluated the in vitro cytotoxic effects of combined human tumour necrosis factor alpha (TNF), human interferon gamma (IFN-gamma), melphalan (L-PAM) and hyperthermia (HTX) on human melanoma cell lines using the crystal violet assay. HTX (40 degrees C, 1 h) alone had no effect. The responses of the cell lines to TNF were in the rank order of 939 cells > 987 > 284 > C8161 > 852 > A2058 approximately 0, and all displayed shallow dose-response curves; no significant thermal enhancement of TNF cytotoxicity was apparent with this heat dose. All cell lines were sensitive to L-PAM, with 284 cells being the most sensitive; HTX caused only slightly increased sensitization to L-PAM. The combination of TNF and L-PAM resulted in generally subadditive or additive cytotoxicity, with or without HTX. The response to IFN-gamma alone was heterogeneous; the 939, 284 and 852 cell lines were sensitive to a dose as low as 20 ng/ml, whereas the 987 line was resistant to 2.0 micrograms/ml, even with HTX. IFN-gamma enhanced the response to TNF only of the TNF-resistant A2058 cell line, but there was no enhancement of the response to L-PAM for any line. Thus, this tetramodality combination achieved generally subadditive or additive cytoxicity in vitro.

Hemodynamic evaluation of recombinant human tumor necrosis factor (TNF)-alpha, TNF-SAM2 and liposomal TNF-SAM2 in an anesthetized dog model

We have evaluated the hemodynamic effects of systemically administered recombinant human tumor necrosis factor (TNF)-alpha, TNF-SAM2 and liposome-bound TNF-SAM2 in an anesthetized mongrel dog model. A dose of 10 micrograms TNF protein/kg of each formulation was injected in a peripheral vein and mean systemic arterial pressure (SAP), heart rate (HR) and cardiac output (CO) were measured. TNF-alpha induced a marked drop in SAP in all three dogs (mean decrease = 59.3 +/- 5.2 mm Hg; to 61.5% of baseline; p = 0.008); whereas TNF-SAM2 caused a smaller and transient drop in SAP in four dogs (mean decrease = 25.5 +/- 10.1 mm Hg; to 81.2% of baseline; p = 0.086). In three dogs administered liposome-bound TNF-SAM2, which retains antitumor activity in vivo, a net slight hypertensive phase and sustained elevated CO occurred, followed by a return to an essentially normotensive state (101.0% of baseline SAP). This model demonstrates that the principal acute systemic toxicity of TNF, i.e., hypotension, can be markedly attenuated by liposomal formulation of a second-generation TNF.

Mechanisms of Kupffer cell cytotoxicity in vitro against the syngeneic murine colon adenocarcinoma line MCA26

We have previously demonstrated that in vivo activation or inhibition of Kupffer cell (KC) cytotoxic function can reduce or enhance, respectively, the hepatic tumor burden in a syngeneic murine colon adenocarcinoma (MCA26) tumor model. In the current study, we have performed in vitro experiments to define the possible mechanisms of KC cytotoxicity against MCA26 cells. Addition of either anti-tumor necrosis factor (TNF) or anti-interleukin-1 alpha (IL-1 alpha) antisera reduced KC cytotoxicity in coculture against MCA26 targets in a dose-dependent fashion; addition of these sera together resulted in approximately additive inhibition, suggesting the existence of parallel pathways for these effector molecules. Nitric oxide as a mediator of cytotoxicity by KCs in coculture with MCA26 cells was evaluated by two approaches. Activated KCs produced detectable levels of nitric oxide; however, activated KC exerted cytotoxicity against MCA26 targets in the absence of exogenous free L-arginine. Thus, TNF and IL-1 play major roles in producing murine KC cytotoxicity against MCA26 colon cancer cells in vitro, whereas reactive nitric oxides do not.