Richard B. Alexander

Detection and Quantitation of Serum Mesothelin, a Tumor Marker for Patients with Mesothelioma and Ovarian Cancer

Purpose: To determine whether mesothelin, a cell surface protein highly expressed in mesothelioma and ovarian cancer, is shed into serum and if so to accurately measure it. Experimental Design: We developed a sandwich ELISA using antibodies reacting with two different epitopes on human mesothelin. To quantitate serum mesothelin levels, a standard curve was generated using a mesothelin-Fc fusion protein. Sera from 24 healthy volunteers, 95 random hospital patients, 56 patients with mesothelioma, and 21 patients with ovarian cancer were analyzed. Serum mesothelin levels were also measured before and after surgical cytoreduction in six patients with peritoneal mesothelioma. Results: Elevated serum mesothelin levels were noted in 40 of 56 (71%) patients with mesothelioma and in 14 of 21 (67%) patients with ovarian cancer. Serum mesothelin levels were increased in 80% and 75% of the cases of mesothelioma and ovarian cancer, respectively, in which the tumors expressed mesothelin by immunohistochemistry. Out of the six patients with peritoneal mesothelioma who underwent surgery, four had elevated serum mesothelin levels before surgery. Out of these four patients, three had cytoreductive surgery and the serum mesothelin level decreased by 71% on postoperative day 1 and was undetectable by postoperative day 7. Conclusions: We developed a serum mesothelin assay that shows that mesothelin is elevated in patients with mesothelioma and ovarian cancer. The rapid decrease in mesothelin levels after surgery in patients with peritoneal mesothelioma suggests that serum mesothelin may be a useful test to monitor treatment response in mesothelin-expressing cancers.

Parenchymal sparing surgery in patients with hereditary renal cell carcinoma

ABSTRACTThe von Hippel-Lindau syndrome is the most well known cause of familial renal cancer. Because affected individuals with renal lesions can have complex, multisystem manifestations of von Hippel-Lindau disease, our renal management strategy has included parenchymal sparing surgery whenever possible. From May 1988 to January 1993, 20 patients with hereditary renal cell carcinoma (19 with von Hippel-Lindau disease and 1 with hereditary papillary renal cancer) underwent renal exploration with the intent of performing parenchymal sparing surgery. A total of 7 nephrectomies and 27 parenchymal sparing procedures was performed. Additional procedures performed included 2 bilateral adrenalectomies for pheochromocytomas, 1 resection of a renal vein thrombus and 1 resection of a pancreatic islet cell tumor. Renal atrophy occurred in 3 of 27 kidneys (11%) treated by parenchymal sparing surgery. In 8 kidneys of 7 patients new solid lesions developed and in 14 kidneys of 12 patients no new solid lesions developed...

Evaluation of color Doppler intraoperative ultrasound in parenchymal sparing renal surgery.

A renal parenchymal sparing surgical approach may be recommended in select patients with von Hippel-Lindau disease and renal cancer or in those with sporadic renal cancer and limited normal renal function. We performed 27 partial nephrectomies or enucleations in 17 patients with the use of intraoperative ultrasound to examine a subset of all renal lesions identified on preoperative examination. Of 24 lesions deep in the renal parenchyma that were examined, localized or identified with intraoperative ultrasound 18 were characterized as cystic and 6 as solid. The deep cystic lesions were characterized with ultrasound as benign simple cysts. Intraoperative ultrasound was used to locate and mark the line of incision over 2 impalpable solid renal cell carcinomas. Four solid renal cell tumors extended deep into the renal parenchyma where color Doppler intraoperative ultrasound helped to define the plane of dissection adjacent to vital vascular structures. Renal hypothermia was not used in 3 renal operations based on intraoperative ultrasound findings.

Adoptively transferred tumor-infiltrating lymphocytes can cure established metastatic tumor in mice and persist long-term in vivo as functional memory T lymphocytes

Tumor infiltrating lymphocytes (TILs) are derived from solid tumors by culturing single cell suspensions of the tumors in low dose interleukin-2 (IL-2) and intermittent tumor stimulation. We have investigated the survival of TILs after intravenous injection into tumor-bearing mice. Using several murine transplantable sarcomas, we examined the in vivo survival of TILs derived from B6.PL Thy 1a/CY mice (Thy-1.1), which were used to treat established experimental metastases in C57BL/6N (Thy-1.2) mice. Donor and host lymphoid cells could be clearly distinguished by fluorescence-activated cell sorting. We found that TILs or TILs + IL-2 could extend the survival of and, in some instances, cure established experimental hepatic and pulmonary metastases. Donor TILs could be recovered from treated animals at all time points tested; in mice cured of pulmonary metastases donor TILs could be detected as late as 119 days after intravenous injection even in the absence of exogenous IL-2. The administration of a relatively low dose of IL-2 in vivo to mice receiving TILs increased the number of donor TILs recovered from the lungs of cured animals 5-10-fold at all time points but did not change the period of time during which donor TILs could be detected in vivo. Additionally, TILs could be recovered from animals cured of established metastases and such cells retained their antitumor activity in vivo. Finally, when mice cured of pulmonary metastases by TILs or TILs + IL-2 were rechallenged with tumor, donor TILs specifically accumulated at the site of tumor rechallenge up to 4 months after adoptive transfer of TILs.(ABSTRACT TRUNCATED AT 250 WORDS)

CD4 and CD8 T-lymphocyte recognition of prostate specific antigen in granulomatous prostatitis.

In order to develop immunotherapies for prostate cancer, many groups are exploring vaccination strategies to induce an immune response against prostate specific antigen (PSA). To determine if T-cell recognition of PSA might be a feature of a naturally occurring human disease, we have studied patients with prostatitis, a poorly understood clinical syndrome of men in which there is evidence that an immune response directed against the prostate may be occurring. We wished to determine if a T-cell response to PSA might be occurring in these patients. We generated long-term T-cell lines from peripheral blood mononuclear cells (PBMC) of one patient with granulomatous prostatitis using purified PSA as an antigen. Several CD4+ and CD8+ TcR &agr;/&bgr;+ T-cell lines were selected for PSA reactivity as measured by at least a threefold increase in IFN-&ggr; secretion in response to PSA presented by irradiated autologous PBMC. CD4 and CD8 T-cell lines recognized PSA in the context of HLA-DR&bgr;1*1501 and HLA-B*0702, respectively. The specificity and HLA restriction of the lines was confirmed using EBV-B cell lines infected with a recombinant PSA-expressing vaccinia virus and also engineered to express PSA by retroviral transfection. HLA-matched targets infected by control vector as well as HLA-mismatched PSA-expressing targets did not induce the response. The data demonstrate that PSA-specific T cells are present in the PBMC of this patient with granulomatous prostatitis, who may be manifesting naturally the type of immune response directed at the prostate that is the goal of prostate cancer immunotherapy. However, the Class I-restricted epitope has not yet been demonstrated to be expressed on the surface of prostate cancer cells. To our knowledge, this is the first demonstration of HLA-DRB1*1501- or HLA-B*0702-restricted responses to PSA and extends the number of HLA molecules accommodating the use of PSA antigen as a candidate vaccine for prostate cancer immunotherapy.

A cytomegalovirus-based vaccine expressing a single tumor-specific CD8+ T cell epitope delays tumor growth in a murine model of prostate cancer

Cytomegalovirus (CMV) is a highly immunogenic virus that results in a persistent, life-long infection in the host typically with no ill effects. Certain unique features of CMV, including its capacity to actively replicate in the presence of strong host CMV-specific immunity, may give CMV an advantage compared with other virus-based vaccine delivery platforms. In the present study, we tested the utility of mouse CMV (mCMV)-based vaccines expressing human prostate-specific antigen (PSA) for prostate cancer immunotherapy in double-transgenic mice expressing PSA and HLA-DRB1*1501 (DR2bxPSA F1 mice). We assessed the capacity of 2 mCMV-based vectors to induce PSA-specific CD8 T-cell responses and affect the growth of PSA-expressing Transgenic Adenocarcinoma of the Mouse Prostate tumors (TRAMP-PSA). In the absence of tumor challenge, immunization with mCMV vectors expressing either a H2-Db-restricted epitope PSA65–73 (mCMV/PSA65–73) or the full-length gene for PSA (mCMV/PSAFL) induced comparable levels of CD8 T-cell responses that increased (inflated) with time. Upon challenge with TRAMP-PSA tumor cells, animals immunized with mCMV/PSA65–73 had delay of tumor growth and increased PSA-specific CD8 T-cell responses, whereas animals immunized with mCMV/PSAFL showed progressive tumor growth and no increase in number of splenic PSA65–73-specific T cells. The data show that a prototype CMV-based prostate cancer vaccine can induce an effective antitumor immune response in a “humanized” double-transgenic mouse model. The observation that mCMV/PSAFL is not effective against TRAMP-PSA is consistent with our previous findings that HLA-DRB1*1501-restricted immune responses to PSA are associated with suppression of effective CD8 T-cell responses to TRAMP-PSA tumors.

In vivo proliferation of adoptively transferred tumor-infiltrating lymphocytes in mice

The adoptive transfer of tumor-infiltrating lymphocytes (TILs) in conjunction with interleukin-2 (IL-2) administration can mediate a reduction in established pulmonary and hepatic metastases of a variety of murine tumors as well as in patients with metastatic melanoma. To characterize further the fate of adoptively transferred TILs, the uptake of the thymidine analog 5-[125I]iodo-2-deoxyuridine ([125I]UdR) into the DNA of dividing cells was used to study the in vivo proliferation and migration patterns of transferred TILs in C57BL/6N mice. Animals received 500 rad of total body irradiation prior to cell transfer to separate incorporation of radiolabel into endogenous lymphoid cells from that into transferred TILs. Mice were subsequently treated with i.v. injections of TILs or no cells followed by i.p. injections of Hanks balanced salt solution or IL-2. At various time points, mice received [125I]UdR, and 20 h later tissues were removed and counted on a gamma analyzer. A proliferation index (PI) was calculated by dividing the mean cpm of organs of experimentally treated mice by the mean cpm of organs of control mice. Animals receiving TILs alone demonstrated small increases in [1251]UdR in the lungs, liver, and spleen of saline-treated controls (PI = 1.4, 1.6, and 1.7, respectively, on day 4), while animals treated with 50,000 U of IL-2 alone showed greater increases in the lungs, liver, kidneys, and spleen (PI = 3.9, 6.1, 3.3, and 15.8). Mice receiving TILs plus IL-2 demonstrated the highest levels of radiolabel incorporation in the same organs (PI = 10.5, 19.4, 10.2, and 22.4). Over a period of 10 days, TIL plus IL-2 treated animals continued to incorporate significantly greater amounts of [125I]UdR for as long as high-dose IL-2 was administered. Animals treated with TILs demonstrated increased incorporation of radiolabel with increasing doses of IL-2. Injection of irradiated TILs did not result in an increased uptake of [1251]UdR into these tissues, thus confirming that TIL proliferation is responsible for the radiolabel uptake in animals receiving TILs alone or TILs plus IL-2. Additionally, fluorescein-labeled anti-Thy-1.1 anti-body identified proliferating TILs derived from congenic B6.PL Thy la/Cy (Thy-1.1) animals in the lungs, spleen, and liver of recipient C57BL/6N (Thy 1.2) mice. In summary, we have demonstrated that adoptively transferred TILs distribute widely after i.v. injection and can proliferate in various tissues especially under the influence of exogenous IL-2.

Isolated perfusion of the kidney with tumor necrosis factor for localized renal-cell carcinoma.

SummaryPatients with localized renal-cell carcinoma who are candidates for renal parenchymal sparing surgery are being treated with isolated renal perfusion with recombinant human tumor necrosis factor (TNF). Isolated organ perfusion is a surgical technique that allows a cancer-bearing organ or region of the body to be treated with high doses of chemotherapy or biologic, agents that would not be tolerated systemically. In patients with in-transit melanoma or unresectable sarcoma, treatment with hyperthermic isolated limb perfusion using TNF, interferon-γ, and melphalan has resulted in response rates exceeding 90%. Because preclinical studies suggest that TNF may induce regression of tumors by causing hemorrhagic necrosis mediated by effects on tumor-related vascular endothelium, a vascular tumor such as renal-cell carcinoma could potentially be very responsive. A phase I study of escalating TNF doses delivered via isolated renal perfusion is currently being conducted.

Defective major histocompatibility complex class I expression in a sarcomatoid renal cell carcinoma cell line

We studied major histocompatibility complex (MHC) class I expression in 12 tumor cell culture lines established from patients with metastatic renal cell carcinoma (RCC). In one of these cell culture lines, UOK 123, we found no surface expression of beta 2-microglobulin (beta 2m) and MHC class I by flow cytometry. Immunofluorescence staining using three different monoclonal antibodies to beta 2m revealed no detectable beta 2m in the endoplasmic reticulum (ER), Golgi apparatus, cytoplasm, or on the cell surface. There was no evidence of folded class I molecules inside or on the surface of the cells; however, the ER stained intensively for unfolded class I molecules. Transient expression of beta 2m by UOK 123 after infection with a recombinant vaccinia virus containing the gene for beta 2m resulted in normal expression of both beta 2m and class I (HLA-A, B, C) determinants assessed by flow cytometry analysis. No expression of class I or beta 2m was seen with the recombinant vaccinia vector carrying a control gene. The inability of class I molecules to reach the cell surface is due to the requirement of beta 2m for proper folding and presentation of the class I MHC complex. The failure to assemble and express MHC class I complex on the cell surface renders these cells incapable of antigen presentation to cytotoxic T cells and provides a mechanism for escape from immune recognition by the tumor.

Helper T Cells Infiltrating Human Renal Cell Carcinomas Have the Phenotype of Activated Memory-Like T Lymphocytes

Summary Human renal cell carcinomas are characterized by an inflammatory infiltrate containing many T lymphocytes. Attempts to grow T cells from such tumors by culture in interleukin (IL)-2 have yielded heterogeneous populations of cells with functional characteristics typical of lymphokine-activated killer cells obtained by similar culture of cells from peripheral blood mononuclear cells. We examined a panel of surface markers expressed on T lymphocytes to determine if the CD4+ T cells infiltrating human renal cell carcinomas are different from those in peripheral blood mononuclear cells. By flow cytometry analysis the CD4+ T cells in a panel of freshly digested human renal cell carcinoma primary and metastatic tumors expressed the activation markers CD69 and HLA-DR and manifested an increase in CD45RO and a reciprocal decrease in CD45RA expression as compared with peripheral blood CD4+ T cells. This suggests that CD4+ T cells infiltrating renal cell carcinomas are activated and have encountered antigen. However, the expression of the IL-2R a chain (CD25) was not different in tumor-infiltrating CD4+ T cells and peripheral blood CD4+ T cells, suggesting that T cells infiltrating human renal cell carcinomas may have a block in proliferative capacity. The general failure of cultured tumor-infiltrating lymphocyte (TIL) from renal cell carcinoma to demonstrate tumor-specific reactivity may be due to the failure of such cells to grow in IL-2.