Chemotherapeutic drugs can enhance an immune response of the host against the tumor in addition to killing cancer cells by direct cytotoxicity. Therefore, the combination of chemotherapy and immunotherapy is a promising approach for eliminating tumors, particularly in advanced stages. A strategic medication is to use a bispecific antibody format that is capable of recruiting polyclonal T cells around antibody-target-expressing tumor cells. Recently, we have constructed a bispecific antibody, anti-CD3 x anti-CD19, in a diabody configuration. In this study, we measured B7 family members B7.1 (CD80) and B7.2 (CD86) expressed on a CD19(+) human leukemia cell line, Nalm-6, stimulated by cytosine arabinoside (Ara-C). We found that a low concentration of Ara-C could upregulate CD80 expressed on CD19(+) Nalm-6 cells. The cytotoxicity of T lymphocytes against Nalm-6 cells in vitro and in vivo mediated by the anti-CD3 x anti-CD19 diabody with or without a low dose of Ara-C was compared. The combination of the anti-CD3 x anti-CD19 diabody and Ara-C showed the greatest effectiveness in enhancing the cytotoxicity of T cells against the tumor cells in vitro and in vivo. Activated T cells expressed higher levels of CD25 and CD69 and released more interleukin 2. Both perforin/granzyme B system and Fas/FasL pathway were involved in the diabody-induced T-cell cytotoxicity. Moreover, the activated T cells could upregulate ICAM-3 expression on Nalm-6 cells, and inhibition of LFA-1-ICAM-3 interaction impaired cytotoxicity of T cells. It was noted that Ara-C could upregulate CD80 expressed on two of five specimens of acute B lymphoblastic leukemia patient-derived cells. Cytotoxicity of T cells against these two patient-derived cells was enhanced in the presence of the anti-CD3 x anti-CD19 diabody. These findings indicate that treatment strategy using both cytotoxic lymphocyte-based immunotherapy and chemotherapy may have synergistic effects.

Radionuclide imaging of head and neck squamous cell carcinoma (HNSCC) using monoclonal antibodies (MAbs) has the potential to contribute to improved diagnosis and staging, thereby making more effective treatment possible. Chimeric monoclonal antibody U36 (cMAb U36), specific to CD44v6 antigen, is a candidate for the targeting of HNSCC. The aim of this study was to compare the influence of indirect iodination via closo-dodecaborate-based linker (DABI) with the influence of direct radioiodination on the biodistribution of the chimeric anti-CD44v6 antibody U36. The study was performed using nude mice bearing UT-SCC7 HNSCC xenografts using the paired-label method. The biodistribution of cMAb U36 labelled directly with 131I and using DABI with 125I was compared in the same animals. The influence of DABI on the tumour-to-organ ratio was evaluated. For both conjugates, radioactivity uptake in blood and organs decreased with time, except in tumours and the thyroid. DABI-labelled cMAb U36 was characterised by fast blood clearance and an elevated uptake in the liver and spleen. The use of DABI enabled a 1.5 to 2-fold improvement in the tumour-to-blood and tumour-to-organ ratios in comparison with direct radioiodination, with the exception of the liver and spleen. These results indicate that DABI is a promising linker for the coupling of radioiodine to HNSCC-targeting antibodies.

CONCLUSIONS:Use of artificial biological material – acellular dermal matrix (Alloderm, ADM) – combined with pectoralis major myocutaneous flaps (PMMFs) or other cervical tissue is a feasible technique with which to reconstruct a large circumferential defect involving the oral cavity and hypopharynx.OBJECTIVE:This paper presents a review of seven patients with advanced hypopharyngeal carcinoma treated at Tianjin Medical University Cancer Institute & Hospital, China, over a 4-year period.METHODS:ADM was used in the form of tissue patches for reconstruction. Five of the seven patients underwent total laryngectomy and total hypopharyngectomy, and reconstruction with a combination of PMMF and ADM tissue patches to restore hypopharyngeal functions. Two other patients underwent tumour resection. The defect in the posterior pharyngeal wall was reconstructed with ADM. Treatment details of the seven patients are discussed.RESULTS:All five PMMFs and seven ADM tissue patches survived. No pharyngeal fistula occurred. Satisfactory healing was observed between the wound margin and ADM 10 days after operation. The trauma area was completely covered by growing epithelium 18–37 days after operation. To some degree, stenosis of the pharyngeal cavity did occur, but patients could have a regular diet following dilatation of the stenosis. Five patients are free of disease after 18–42 months of follow-up.

Conclusions. Malignant carotid body tumour (MCBT) is a clinically rare disease that often invades the carotid artery and cranial nerves. Diagnosis of malignant tumour should be based on extensive invasion of neighbouring organs and distant metastasis. Extensive resection should be undertaken early. Radiotherapy is effective, whereas chemotherapy is uncertain. Objective. To summarize the clinical pathological and prognostic characteristics of MCBT and explore methods for diagnosis and treatment. Materials and methods. The study material comprised clinical, pathological, therapeutic and follow-up data concerning nine patients (four males, five females) with MCBT, treated at Tianjin Cancer Hospital between January 1956 and June 2006. The material was analysed retrospectively. Disease duration averaged 6.4 years. Shamblin classification was: one case, type II; 8 cases, type III. All nine patients underwent ultrasound examination, four underwent digital subtraction arteriography (DSA) and three had magnetic resonance angiography (MRA). Five patients underwent preoperative training of compression of the carotid (Matas test). Extensive resection was performed in all nine cases. Results. The carotid artery was blocked in three patients. In one of these the artery was reconstructed with a vascular prosthesis, while two underwent carotid ligation. Eight patients suffered from a cranial nerve dysfunction (defect) and two suffered postoperatively from a hoarse voice, four had a glossal deviation, five had Horner's syndrome and one had a deviation of the lip angle. One patient had a congestive cough. The histopathological diagnosis in all nine cases was MCBT. One patient had metastases to a cervical lymph node and lung and another had liver metastasis. The median follow-up period was 3 years (range 6 months to 14 years). Six patients survived surgery, of whom two underwent radiotherapy. Two patients died and one could not be traced.

Objectives: In advanced head and neck squamous cell carcinoma (HNSCC), there is a need for an adjuvant treatment. We aim to evaluate the biodistribution and therapeutic effect of radioimmunotherapy using the alpha emitting, astatine-211-labeled, chimeric monoclonal antibody U36 (U36) on the HNSCC cell line UT-SCC7 in vivo.Study Design: Xenograft tumors were inoculated subcutaneously in nude mice. Astatine-211-labeled U36 was injected intravenously with or without blocking of target with nonlabeled U36.Methods: In the biodistribution experiments, radioactivity was measured in tumors and various organs at set time points. In the therapeutic experiments, two groups (with or without blocking) received therapy, and the tumor growth was compared with that of controls. In addition, one group received nonlabeled U36 only.Results: The biodistribution experiments demonstrated that astatine-211-labeled U36 could target UT-SCC7 xenografts in nude mice. With time, uptake increased in tumors and decreased in normal organs. Nonlabeled U36 did not influence tumor growth. In the two therapy groups, 18 of 20 tumors responded to therapy by decreasing or stabilizing their volumes. Significant difference was seen between the treated groups and the controls (P < .05).Conclusion: The stud illustrates the specific binding of astatine-211-labeled U36 to HNSCC and suggests, radioimmunotherapy with the alpha emitting radionuclide to be a useful treatment modality.

A sustained release poly(DL-lactide-co-glycolide) (PLGA) microsphere delivery system to treat prostate cancer for a luteinizing hormone-releasing hormone (LHRH) antagonists, LXT-101 was prepared and evaluated in the paper. LXT-101 microspheres were prepared from PLGA by three methods: (1) double-emulsion solvent extraction/evaporation technique, (2) single-emulsion solvent extraction/evaporation technique, and (3) S/O/O (solid-in-oil-in-oil) method. The microspheres were investigated on drug loading, particle size, surface morphology and in vitro release profiles. An accelerated release approach was also established in order to expedite the evaluation periods. The in vivo evaluation of the microspheres was made by monitoring testosterone levels after subcutaneous administration to rats. The LXT-101 PLGA microspheres showed smooth and round surfaces according to a scanning electron microscopic investigation, and average particle size of ca. 30 mum according to laser diffractometry. The drug encapsulation efficiency of microspheres was influenced by LA/GA ratio of PLGA, salt concentrations, solvent mixture and preparation methods. Moreover, LA/GA ratio of PLGA, different preparation methods and different peptide stabilizers affected in vitro release of drugs. In vivo study, the testosterone levels were suppressed to castration up to 42 d as for the 7.5 mg/kg dose. And in vivo performance of LXT-101 microspheres was dose-dependent. The weights of rat sexual organs decreased and histopathological appearance of testes had little changes after 4-month microspheres therapy. This also testified that LXT-101 sustained release microspheres could exert the efficacy to suppress the testosterone level to castration with little toxicity. In conclusion, the PLGA microspheres could be a well sustained release system for LXT-101.

Radioimmunotherapy with 211 Astatine, using chimeric monoclonal antibody U36 in hed and neck squamous cell carcinoma in vivo

OBJECTIVE:High rates of local recurrence and distant metastases following surgery of high-grade head and neck squamous cell carcinoma (HNSCC) necessitate the use of adjuvant systemic treatment. Radioimmunotargeting might be a possible treatment modality in this case. The nuclear properties of 131I make it a suitable isotope for treatment of minimal residual disease and small metastases, but the conventional radioiodine label has poor cellular retention and its radiocatabolites accumulate in the thyroid. We attempted to overcome these problems by using closo-dodecaborate derivatives for attachment of radioiodine.MATERIAL AND METHODS:We investigated the feasibility of targeting an SCC25 HNSCC xenograft in vivo using a benzylisothiocyanate derivative of closo-dodecaborate (DABI) as radioiodine linker and the chimeric anti-CD44v6 antibody U36. 125I was used in biodistribution studies.RESULTS:The use of DABI enabled tumor targeting and decreased the radioactivity uptake of the thyroid.CONCLUSION:Tumor localization of DABI-labeled U36 was similar to its para-iodobenzoate-labeled counterpart, presumably due to the strong dependence of targeting efficiency on tumor size.

We have evaluated the applicability of the [(4-isothiocyanatobenzylammonio)undecahydro-closo-dodecaborate (1-)] (DABI) linker molecule for antibody radiohalogenation and compared it to radiohalogenation using the linker N-succinimidyl 4-iodobenzoate (PIB) and to direct radiohalogenation using Chloramine T. These studies were performed to assess the potential of DABI conjugates and to optimize the biological properties of halogen-labeled cMAb U36. The three conjugates were evaluated in vitro for their specificity and affinity and in vivo for their biodistribution patterns in normal mice at 1.5, 6, 24, and 96 h pi. Labeling efficiencies of direct CAT labeling, indirect PIB labeling, and indirect DABI labeling were 90-95%, 60%, and 68%, respectively. This resulted in a PIB:cMAb U36 molar ratio of 1.8-2.5 and a DABI:cMAb U36 molar ratio of 4.1. The in vitro data demonstrated specific binding for all conjugates and similar affinities with values around 1 x 10(8) M(-)(1). However, the in vivo data revealed accumulation of the radioiodine uptake in thyroid for the directly labeled conjugate, with a value 10 times higher than the indirectly labeled conjugates 96 h pi. Both the (125)I-PIB-cMAb U36 and (125)I-DABI-cMAb U36 conjugates yielded a low thyroid uptake with no accumulation, indicating different catabolites for these conjugates. This may favor the use of the indirectly labeled conjugates for future studies. Apart from the specific results obtained, these findings also demonstrate how the right linker molecule will provide additional opportunities to further improve the properties of an antibody-radionuclide conjugate.

Radioimmunotherapy (RIT) has been shown to be a practicable way to treat head and neck squamous cell carcinoma. A specific antibody recognizes the charasteristic structure of tumour cells when loaded with cytotoxic agents (toxins, drugs, radionuclides, etc). But RIT kills not only tumour cells with attached radionuclides but also adjacent tumour cells due to the “cross fire effect”. To be efficacious, RIT depends closely on suitable monoclonal antibody, on the properties of the chosen radionuclides, and on a suitable labelling method for attaching radionuclide to antibody. In this study we initially used radionuclide-labelled cMAB U36, via linker DABI in order to improve the retention of radio-conjugates in the tumour cells. Improved retention is important because the longer the radionuclide remains in tumour cells, the more effective will the tumour cells be eradicated. In the investigation, both normal mice and HNSCC-bearing nude mice were used to compare our form of treatment against other radio-iodination methods. In the biodistribution study, normal mice showed that radioactive uptake in organs diminished with time, irrespectively of whether the conjugate was directly or indirectly labelled. But in thyroid, there was a tenfold greater accumulation of direct-labelled than of indirectly labelled conjugate.In tumour-bearing nude mice, by contrast, the results showed promising uptake of radioactivity, but little uptake in direct-labelled conjugate in thyroid. Significant differences were observed on comparing tumour: organ ratios between 131I-cMAb U36 vs. 125I-DABI-cMAb U36.In the present study, cMAb U36 labelled with 211Astatine was initially used to treat HNSCC in nude mice. The biodistribution of 211At-cMAb U36 did not reveal any significant difference between an antibody-blocked group and a non-blocked group. But it did highlight the characteristics of a successful targeting conjugate in HNSCC-bearing nude mice.In the subcutaneous therapy experiment, most of the treated tumours (n=18) had disappeared by the 26th day, in both U36-blocked and non-blocked groups. Treatment in the intravenous therapy experiment had also proved effective. In the antibody non-blocked group, the smallest tumour volume was 25 mm3 (average 111 mm3) vis-a-vis 65 mm3 (average 145 mm3) in the blocked group. None of tumours grew again following treatment.