Rapamycin-induced endothelial cell death and tumor vessel thrombosis potentiate cytotoxic therapy against pancreatic cancer

PURPOSE

Despite current chemotherapies, pancreatic cancer remains an uncontrollable, rapidly progressive disease. Here, we tested an approach combining a recently described antiangiogenic drug, rapamycin, with standard gemcitabine cytotoxic therapy on human pancreatic tumor growth.

EXPERIMENTAL DESIGN

Tumor growth was assessed in rapamycin and gemcitabine-treated nude mice orthotopically injected with metastatic L3.6pl human pancreatic cancer cells. H&E staining was performed on tumors, along with Ki67 staining for cell proliferation and immunohistochemical terminal deoxynucleotidyl transferase-mediated nick end labeling and CD31 analysis. Rapamycin-treated tumor vessels were also directly examined in dorsal skin-fold chambers for blood flow after thrombosis induction. Cell death in human umbilical vein endothelial cells was assessed by flow cytometry after annexin-V staining.

RESULTS

Rapamycin therapy alone inhibited tumor growth and metastasis more than gemcitabine, with remarkable long-term tumor control when the drugs were combined. Mechanistically, H&E analysis revealed tumor vessel endothelium damage and thrombosis with rapamycin treatment. Indeed, dorsal skin-fold chamber analysis of rapamycin-treated tumors showed an increased susceptibility of tumor-specific vessels to thrombosis. Furthermore, terminal deoxynucleotidyl transferase-mediated nick end labeling/CD31 double staining of orthotopic tumors demonstrated apoptotic endothelial cells with rapamycin treatment, which also occurred with human umbilical vein endothelial cells in vitro. In contrast, gemcitabine was not antiangiogenic and, despite its known cytotoxicity, did not reduce proliferation in orthotopic tumors; nevertheless, rapamycin did reduce tumor proliferation.

CONCLUSIONS

Our data suggest a novel mechanism whereby rapamycin targets pancreatic tumor endothelium for destruction and thrombosis. We propose that rapamycin-based vascular targeting not only reduces tumor vascularization, it decreases the number of proliferating tumor cells to be destroyed by gemcitabine, thus introducing a new, clinically feasible strategy against pancreatic cancer.

Vascular endothelial growth factor in colorectal cancer

Angiogenesis plays an important role in colorectal cancer progression. Evidence from preclinical and clinical studies indicates that vascular endothelial growth factor (VEGF) is the predominant angiogenic factor in human colorectal cancer and is associated with formation of metastases and poor prognosis. Based on these results it was hypothesized that attacking one or more of the VEGF-mediated mechanisms may be promising in the treatment of colorectal cancer. AIMS. This article reviews the role of VEGF in colon cancer and summarizes recent advances in the treatment of colorectal cancer by anti-VEGF strategies.

Blockage of 2-deoxy-D-ribose-induced angiogenesis with rapamycin counteracts a thymidine phosphorylase-based escape mechanism available for colon cancer under 5-fluorouracil therapy

PURPOSE

Colorectal neoplasms remain a leading cause of cancer-related deaths. A recognized weakness of conventional 5-fluorouracil (5-FU) therapy relates to expression of the intracellular enzyme, thymidine phosphorylase (TP). Although TP promotes 5-FU cytotoxicity, TP-derived 2-deoxy-D-ribose (dRib) counterproductively stimulates tumor angiogenesis. Here, the newly discovered antiangiogenic drug rapamycin was combined with 5-FU to counteract the potential escape mechanism of dRib-induced angiogenesis.

EXPERIMENTAL DESIGN

Orthotopic tumor growth was assessed in rapamycin and 5-FU-treated BALB/c mice with TP-expressing CT-26 colon adenocarcinoma cells. To examine liver metastasis, green-fluorescent protein-transfected CT-26 cells were visualized by fluorescence microscopy after intraportal injection. Cell counting and Ki67 staining were used to determine in vitro and in vivo cell expansion, respectively. In vitro angiogenic effects of dRib were assessed with endothelial cell migration and aortic ring assays. Western blotting detected dRib effects on p70/S6 kinase activation.

RESULTS

Rapamycin treatment of mice bearing orthotopic tumors inhibited tumor growth more than did 5-FU, and mice treated with both drugs typically developed no tumors. In the liver metastasis assay, combination therapy blocked metastatic expansion of solitary tumor cells. Interestingly, complex drug activities were suggested by tumor-cell proliferation being more sensitive to 5-FU than to rapamycin in vitro, but more sensitive to rapamycin in vivo. With regard to angiogenesis, dRib-induced endothelial cell migration and aortic ring formation were completely abrogated by rapamycin, correlating with blockage of dRib-induced p70/S6 kinase activation in endothelial cells.

CONCLUSIONS

Inhibition of dRib-induced angiogenesis with rapamycin counteracts a potential TP-based escape mechanism for colorectal cancer under 5-FU therapy, introducing a novel, clinically feasible, combination treatment option for this common neoplasm.

Minimal residual disease in gastric cancer

In curatively resected gastric cancer, the incidence of distant relapse is as high as 30%. Although the most important factor contributing to the local control of the tumor is the microscopic tumor-free margin of the surgical resection, the occurrence of distant metastases is in many cases due to preoperative or perioperative tumor cell dissemination. In addition to the established TNM staging system, disseminated tumor cells may serve as independent prognostic factors influencing patient outcome after curative surgery. Basically, in gastric cancer three compartments have been identified in which single tumor cells may be shed: lymph nodes, peritoneal cavity, and bone marrow. Assessment of resected regional lymph nodes with monoclonal antibodies directed against cytokeratin antigens leads to an upstaging in comparison with conventional histology. Nodal micrometastases detected by immunohistochemistry result in an upstaging of up to 36% of patients. However, their prognostic significance remains controversial. Local dissemination of tumor cells in the peritoneal cavity determines the outcome in advanced gastric cancer and diffuse-type carcinoma. Patients with negative peritoneal washings seem to have a more favorable prognosis. Moreover, with the use of these diagnostic tools, patient subpopulations may be identified which profit from intraperitoneal therapy regimens. Diffuse hematogenous tumor cell dissemination into the bone marrow has been shown to be a prognostic factor in several studies. In our own population of 180 gastric cancer patients, bone marrow cells were screened immunohistochemically with a monoclonal antibody directed against cytokeratin 18 (CK18). In 95 patients (53%), CK2-posititve cells were detected. In a multivariate analysis, the independence of the presence of three or more disseminated tumor cells per 10(6) mononuclear cells was proven to be a prognostic factor in patients with intestinal-type tumors, pT1/2 status, and pN0 status. In conclusion, the TNM status only partially reflects the actual extent of systemic disease in patients with resected gastric cancer. The assessment of minimal residual disease is valuable in estimating the prognosis in many patients. In the future, staging systems will have to not only include TNM data but also provide specific information on biological properties of residual cancer cells in order to establish more exact prognostic estimates and provide patients with an individually tailored multimodal treatment.

[Endoscopic Therapy of Early Colorectal Cancer (pT1) - A Prospective Study]

INTRODUCTION

In a prospective study initiated in 1982, we have been investigating the question as to whether - and if so, which - pT1 carcinomas of the colorectum can be treated exclusively via the endoscope.

METHOD

In the period between February 1, 1982 and April 30, 2001, a total of 5,470 polyps were removed endoscopically at the Medical Department I of the Klinikum Ludwigsburg. Among these lesions, a total of 144 (2.6 %) pT1 carcinomas were found in 141 patients. We were able to follow 120 patients with 123 pT1 carcinomas over a mean follow-up period of 46 months (range: 1-60). In low-risk situations (definitive removal in healthy tissue, G1-G2, no lymphatic involvement), endoscopic treatment alone usually represented sufficient treatment. In high-risk cases (removal in healthy tissue uncertain or negative, and/or lymphatic vessel involvement, and/or G3/G4), subsequent surgical resection was carried out.

RESULTS

64 cases were classified as high-risk, 59 as low-risk. Nevertheless, 9 patients with 10 low-risk carcinomas were submitted to surgery (young age, patient's own request). In none of these 10 cases was residual tumour or lymph node metastasis detected in the surgical specimen. 47 patients with 49 low-risk carcinomas were treated solely by endoscopic polypectomy using the diathermy snare, and 45 patients with 47 carcinomas remained recurrence-free during the follow-up period. In a single case, a local recurrence was detected 2 months after polypectomy and underwent curative resection. In another case, peritoneal carcinosis with tumour infiltrating into the colon developed 8 months after initial treatment; this, however, was most probably a recurrence of a previously operated carcinoma of the uterus. Among the high-risk cases, 10 were not submitted to surgery on account of advanced age and/or rejection of an operation by the patient; all remained recurrence-free. Among the surgically treated high-risk carcinomas, 3 surgical specimens contained residual tumour, while 2 revealed a lymph node metastasis. In our group of patients, no tumour-related mortality was seen among endoscopically treated patients.

DISCUSSION

In the light of the fact that the reported mortality rate associated with open surgery for colorectal carcinoma is 3 % as compared with about 1 % risk of lymph node metastasis and 0,1 % mortality rate for the endoscopic modality, endoscopic removal of a pT1 tumour in a low-risk situation followed by appropriate surveillance can be considered as adequate treatment.

Surgical management of bile duct injuries following laparoscopic cholecystectomy: analysis and follow-up of 28 cases

BACKGROUND

Biliary tract lesions pose a dreaded complication of laparoscopic cholecystectomy. In a retrospective study we analyzed the clinical presentation, diagnostic and therapeutic management and outcome of 28 patients presenting with iatrogenic bile duct injuries.

PATIENTS AND METHODS

Between 1994 and 2001 we treated 28 patients with bile duct lesions following laparoscopic cholecystectomy at our center. Operation notes and charts of all patients were reviewed systematically. A follow-up examination of each patient was performed after a median of 12 months (range 1-90).

RESULTS

Twenty-two patients presented with major circumferential bile duct defect lesions. Less severe injuries (n=6) were two minor bile leaks, one bile duct stricture and three tangential lesions. Twenty-six patients were referred to our institution within 16 days (range 0-226 days). Six patients were treated by nonsurgical procedures: endoscopic stenting in four and percutaneous intervention in two. In one of the remaining patients a cystic duct leak was closed via laparotomy, and in 21 a hepaticojejunostomy was performed. Reconstruction of a hepaticojenunostomy was performed in two of these patients. Patients were dismissed from the hospital after a median of 13 days (range 4-156). Four patients presenting with generalized biliary peritonitis required prolonged intensive care. One or more episodes of cholangitis were seen in five patients during follow-up examinations.

CONCLUSIONS

Major iatrogenic bile duct injuries are associated with high morbidity and prolonged hospitalization. Interdisciplinary cooperation and early referral to an experienced center is crucial in the management of patients suffering from this affliction. Cholangitis is a marked problem in the follow-up.

Transplantation of H-2Kb-transgenic adrenocortical cells in the mouse having undergone an adrenalectomy: functional and morphological aspects

BACKGROUND

A new model of cellular adrenocortical transplantation after bilateral adrenalectomy in the mouse was established. This model was used to study the effects of the expression of the transgenic MHC class I molecule H-2K(b) (Kb) on graft survival and morphologic features, corticosterone secretion, and the possibility of tolerance induction in the recipient.

METHOD

A single cell suspension of purified adrenocortical cells was grafted under the kidney capsule of B10.Br (H-2k) mice having adrenalectomies. Syngeneic, fully MHC-mismatched, and MHC class I-incompatible Kb-transgenic mice served as donor strains. To analyze graft function, urinary excretion and serum levels of corticosterone were monitored over 100 days. Tolerance induction in the graft recipients of Kb-transgenic and third party skin grafts was tested on day 50 after adrenocortical transplantation. Histological sections of the adrenocortical grafts were obtained on day 100.

RESULTS

Recipients of syngeneic and Kb-transgenic grafts displayed pretransplant corticosterone levels on days 20, 50, and 100 and ACTH-stimulated serum corticosterone levels similar to those of controls on day 100 after adrenocortical transplantation. In contrast, in recipients of fully MHC-mismatched grafts, corticosterone excretion was significantly reduced. In this group, 4 of 7 mice did not survive. Syngeneic skin grafts survived indefinitely in recipients of syngeneic and Kb-transgenic adrenocortical grafts, whereas Kb-transgenic and fully MHC-mismatched skin grafts were acutely rejected. Tissue sections of the adrenocortical grafts revealed vascularized cell conglomerates in syngeneic and Kb-transgenic grafts without infiltrations of mononuclear cells. Furthermore, a differentiation similar to adrenocortical organization was partly found.

CONCLUSION

In conclusion, a model of cellular adrenocortical transplantation was established. The results show that syngeneic transplantation resulted in physiological corticosterone levels early after transplantation, whereas fully MHC-incompatible grafts were rejected. Recipients of Kb-transgenic grafts showed unimpaired adrenocortical function, but did not tolerize toward Kb-transgenic skin grafts. Possible mechanisms include a local immunomodulatory effect of glucocorticoids secreted by the graft and a low immunogenicity of the relatively small numbers of transplanted cells.

Behaviorally conditioned immunosuppression using cyclosporine A: central nervous system reduces IL-2 production via splenic innervation

Bi-directional interactions between the central nervous system (CNS) and immune system are demonstrated by the modification of immune function using behavioral conditioning. However, the mechanisms by which the CNS achieves conditioned immunomodulation are still in question. Here, we report that the immunosuppressive effects of cyclosporine A (CsA) can be behaviorally conditioned in rats using saccharin as a gustatory conditioned stimulus. The conditioned effects were compared to control groups that received CsA paired with water (sham-conditioned), CsA injection on test days (CsA-treated), and unhandled rats (untreated). In conditioned animals, the mitogen-induced lymphocyte proliferation in the spleen is significantly suppressed, and the survival time of heterotopic heart allografts prolonged. These effects are paralleled by conditioned inhibition of IL-2 and IFN-gamma synthesis by splenocytes. Furthermore, the CNS-induced immunosuppression is mediated neuronally and not via the blood, since the conditioned reduction of proliferation and cytokine production is completely abrogated after surgical denervation of the spleen. Thus, during conditioning, the CNS learns to reinstate at demand a CsA-like immunosuppression via splenic innervation. This might be used as a supportive therapy for controlling immune functions.

A fatal case of Listeria endocarditis in a man following his tending of goats suggests an epidemiological link which is not supported by the results

A man died in endocarditis due to listeriosis in the late autumn. He had been looking after two goats during the summer. Listeria monocytogenas was isolated from a rectal swab from one of the goats. The goat faeces isolate and the human blood isolate were of identical serovar. The two isolates, however, were shown to be different by multilocus electrophoretic enzyme analysis and ribotyping, as well as by biotyping. Thus, these results do not support the hypothesis that the man was infected by the goat.

Completion thyroidectomy in 131 patients with differentiated thyroid carcinoma

OBJECTIVE

To evaluate the prognostic factors that influence survival and recurrence after "completion" thyroidectomy (removal of the total thyroid remnant after diagnosis of carcinoma has been made in a specimen that was incompletely excised for a benign condition).

DESIGN

Open study.

SETTING

Teaching hospital, Germany.

SUBJECTS

131 Patients (65 with papillary and 66 with follicular thyroid cancer) who underwent completion thyroidectomy after primary subtotal resection.

INTERVENTIONS

Indications for further operation were: tumour stage worse than pT1 ( n = 116), tumour stage pT1 and the suspicion of persistence of the tumour (n = 13), and incompletely resected tumour (n = 2). Multivariate analysis by Cox's proportional hazards model.

MAIN OUTCOME MEASURES

Recurrence, development of metastases, and length of survival.

RESULTS

Patients who underwent their completion thyroidectomies within six months of the primary operation had significantly fewer recurrences, fewer lymph node metastases, fewer haematogenous metastases and survived significantly longer than those in whom the second operation was delayed for longer than six months. The age at the time of diagnosis and the stage of the tumour influenced survival, whereas sex and type of tumour did not.

CONCLUSION

Completion thyroidectomy as soon as possible after incomplete resection of the tumour may improve prognosis in differentiated thyroid cancers the stage of which is worse than pT1 or in patients whose recurrent tumour is diagnosed at follow-up.

[The value of fine needle puncture in adrenal gland tumors]

The value of fine needle biopsy (FNB) in adrenal masses was investigated in 33 patients presenting with such masses. Representative material was obtained 18 times from 19 patients with a history of tumour. 4 of them were diagnosed to be genuinely benign and 14 to be genuinely malignant. Further representative material was obtained 13 times from 14 patients with incidental findings of adrenal masses. The material gained by puncturing was classified correctly as benign in 9 cases, and twice it was considered benign although the tumours later proved malignant. In one case a clinically not suspected malignant lesion was detected by FNB, while in another case a malignant lesion was suspected by FNB, whereas a benign tumour was proven by means of surgery. The share of malignant diagnoses corresponded with the size of tumour, ascertained by the application of ultrasound or CT. The rate of malignant adrenal masses, which were found incidentally, increased from 7 cm onwards; however, the rate of malignant adrenal masses obtained from patients with a history of tumour increased distinctively already from 4 cm onwards. From 11 patients out of 33, adrenal tissue was obtained and classified as benign lesion (adenoma), although, by means of FNB and the conditions for reasons of method, a well differentiated carcinoma cannot be excluded.

CONCLUSION

FNB is indicated for non-functioning tumours examined in patients with a history of tumour, furthermore, for incidental findings of the size between 4-6 cm. A diagnostic approach to adrenal masses is suggested.

Endoscopic polypectomy and management of colorectal adenomas with invasive carcinoma

BACKGROUND AND STUDY AIMS

Invasive carcinoma is found at histology in 2-5% of colorectal polyps removed under flexible endoscopy. The aim of this study was to confirm that histologically complete endoscopic polypectomy under favorable low-risk conditions is sufficient therapy for pT1 carcinoma, while tumors at or close to the margin of the polypectomy, and histological high-risk criteria, require surgical resection with lymphadenectomy.

PATIENTS AND METHODS

Eighty-six patients with 87 pT1 carcinomas underwent polypectomy within a twelve-and-a-half-year period. Further treatment prospectively followed the above guidelines. The follow-up was documented.

RESULTS

A local tumor residue was found in 5 of 34 patients who had undergone surgical resection for doubtful or incomplete polypectomy. Two patients were found to have nodal disease in the surgical specimen, only one of them harboring a high-risk carcinoma. Two further patients with high-risk carcinomas had tumor progression, despite postpolypectomy resections without local tumor residue or lymph-node infiltration, and died. One patient had a local tumor recurrence on follow-up endoscopy eight weeks after doubtfully complete polypectomy. He underwent resection, and had no further recurrence. No further manifestations of invasive carcinoma occurred after complete polypectomy of 42 patients with low-risk carcinomas.

CONCLUSIONS

This study supports the view that complete endoscopic polypectomy is an adequate therapy for low-risk carcinoma: A modification of the follow-up regimen, with less frequent endoscopic controls, is justified.

[Benign chondroma of the pancreas]

Fragments of a puncture cylinder were obtained from a pancreas tumour, using the ultrasound-guided fine-needle puncture. The tumour appears as an echo-poor, homogeneous structure suggesting good delineation against the adjoining tissue. Histological examination of the punch cylinder revealed a chondroma of the pancreas. Clinical and clinical pathology examinations (lipase, alpha-amylase, glucose, CEA, CA 19-9 in serum) were inconspicuous. Chondroma of the pancreas does not require specific treatment.

Madura foot. A report of two cases

Two cases of Madura foot which originated in the Middle East are described. This so-called maduramycosis is a chronic progressive infection caused by thread fungi or actinomycetes. The diagnosis is confirmed when the grains of mycetoplaits are demonstrated in the discharge from a sinus. Clinical findings and treatment are discussed. Medical treatment may be needed for several months, but operation is indicated for infections caused by the true fungi (eumycetoma).

[Papillary fibroelastoma of the aortic valve: primary echocardiography diagnosis in an asymptomatic patient]

A rare case of a cardiac tumor located between the right coronary ostium and cusp of the aortic valve is reported. Diagnosis was confirmed by two-dimensional echocardiography. Histologic evaluation revealed a papillary fibroelastoma.

[The dilemma of listeriosis control by the public health office]

The frequent occurrence of Listeria monocytogenes both superficially and in certain foods requires measures in accordance with the Federal Laws on Communicable Diseases and Safe Foods to study possible sources of the infectious agent and prevention if positive findings are reported. On the other hand, due to good defence mechanisms, the majority of the population are not at great risk. This excludes, however, immunodeficient patients, aged persons and newborn. The Federal Law on Notifiable Diseases requires only the reporting of meningitis and encephalitis as well as of listeriosis in newborn. Hence, Listeria infections with other syndromes are not registered. The some-times relatively long time of incubation and the lack of knowledge on mild and transient forms of listeriosis render the search for sources of such infections rather difficult. This results in a true dilemma. -Thus, it appears at the present to be more important to encourage strongly the producers of Listeria-endangered food, to eliminate the risk by all possible means. This, however, appears to be applicable only in a few food items. Therefore, the consumer should be more thoroughly informed, so that at least for the 'at risk' part of the population any possible danger may be minimised. Particular attention should be paid to impart good knowledge on the possibilities of preventing listeriosis by appropriately efficient methods of food preparation.

[Ultrasound controlled fine needle cytology and fine needle histology in circumscribed pancreatic processes]

Using a biopsy transducer 171 fine-needle punctures of focal pancreatic processes were done in 158 patients. The final diagnosis was made in the first group by surgical operation or autopsy, in the second by the further clinical course. The sensitivity of the cytological examination alone was 78% in the first group and 90% in the second. The histological examination alone had a sensitivity of 79% to 100%. Combining both ways of examination according to defined criteria the sensitivity in the first group was 84% and in the second 100%. The specificity was 100% for both. The complications were 2.9%. Of these 5 cases one pancreatitis had to be operated. There were no lethal complications. To optimize the sensitivity and specificity of the ultrasound guided fine needle puncture technique we want to recommend the following points: A biopsy transducer or puncture-aid must be available. The fine needle technique only should be done under the prerequisite of a high frequency of punctures and a high constancy in the relation between puncturer and pathologist. To receive representative material it can be necessary to make several needle passes during one session. Material for cytological und histological examination should always be taken simultaneously.

Papillary carcinoma of the prostate, location, morphology, and immunohistochemistry: the histogenesis and entity of so-called endometrioid carcinoma

Fifty carcinomas that were partially to completely papillary in nature were examined. According to urethroscopic and rectal palpation findings, six of the carcinomas were located centrally, 40 tumors were in the prostate proper, and four were clinical stage T0. The epithelium of the papillary portions of the tumors was dark in some instances, light in others. Immunohistochemistry revealed that 20 of 22 tumors were positive for prostatic acid phosphatase (PAP) and prostate-specific antigen (PSA). In no case was a topical relationship to the utriculus prostaticus demonstrable. The epithelium of the utriculus in seven additional patients who were not involved in this series also stained positively for PAP and PSA. Usual carcinomas of the prostate proper can develop endometrioid structures that do not differ immunohistochemically from ordinary portions of the carcinoma. Tumors located in central portions of the prostate are, in our opinion, morphologic variants of usual prostatic carcinomas, and apparently arise in prostatic ducts. We conclude that a distinction between endometrioid carcinomas and tumors of prostatic ducts does not seem justified and that papillary prostatic carcinomas should be treated like common prostatic cancer.