Overall survival by clinical risk category for high dose interleukin-2 (HD IL-2) treated patients with metastatic renal cell cancer (mRCC): data from the PROCLAIMSM registry

BACKGROUND

Prognostic scoring systems are used to estimate the risk of mortality from metastatic renal cell carcinoma (mRCC). Outcomes from different therapies may vary within each risk group. These survival algorithms have been applied to assess outcomes in patients receiving T-cell checkpoint inhibitory immunotherapy and tyrosine kinase inhibitor therapy, but have not been applied extensively to patients receiving high dose interleukin-2 (HD IL-2) immunotherapy.

METHODS

Survival of 810 mRCC patients treated from 2006 to 2017 with high dose IL-2 (aldesleukin) and enrolled in the PROCLAIMSM registry data base was assessed utilizing the International Metastatic RCC Database Consortium (IMDC) risk criteria. Median follow-up is 23.4 months (mo.) (range 0.2-124 mo.). Subgroup evaluations were performed by separating patients by prior or no prior therapy, IL-2 alone, or therapy subsequent to IL-2. Some patients were in two groups. We will focus on the 356 patients who received IL-2 alone, and evaluate outcome by risk factor categories.

RESULTS

Among the 810 patients, 721 were treatment-naïve (89%) and 59% were intermediate risk. Overall, of the 249 patients with favorable risk, the median overall survival (OS) is 63.3 mo. and the 2-year OS is 77.6%. Of 480 patients with intermediate risk, median OS is 42.4 mo., 2-year OS 68.2%, and of 81 patients with poor risk, median OS 14 mo., 2-year OS 40.4%. Among those who received IL-2 alone (356 patients), median OS is 64.5, 57.6, and 14 months for favorable, intermediate and poor risk categories respectively. Two year survival among those treated only with HD IL-2 is 73.4, 63.7 and 39.8%, for favorable, intermediate and poor risk categories respectively.

CONCLUSIONS

Among mRCC patients treated with HD IL-2, all risk groups have median and 2-year survival consistent with recent reports of checkpoint or targeted therapies for mRCC. Favorable and intermediate risk (by IMDC) patients treated with HD IL-2 have longer OS compared with poor risk patients, with most durable OS observed in favorable risk patients. Favorable risk patients treated with HD IL-2 alone have a 2-year OS of 74%. These data continue to support a recommendation for HD IL-2 for patients with mRCC who meet eligibility criteria.

TRIAL REGISTRATION

PROCLAIM, NCT01415167 was registered with ClinicalTrials.gov on August 11, 2011, and initiated for retrospective data collection until 2006, and prospective data collection ongoing since 2011.

Axitinib versus sorafenib in advanced renal cell carcinoma: subanalyses by prior therapy from a randomised phase III trial

BACKGROUND

In the AXIS trial, axitinib prolonged progression-free survival (PFS) vs sorafenib in patients with advanced renal cell carcinoma (RCC) previously treated with sunitinib or cytokines.

METHODS

In post hoc analyses, patients were grouped by objective response to prior therapy (yes vs no), prior therapy duration (< vs ⩾median), and tumour burden (baseline sum of the longest diameter < vs ⩾median). PFS and overall survival (OS), and safety by type and duration of prior therapy were evaluated.

RESULTS

Response to prior therapy did not influence outcome with second-line axitinib or sorafenib. PFS was significantly longer in axitinib-treated patients who received longer prior cytokine treatment and sorafenib-treated patients with smaller tumour burden following sunitinib. Overall survival with the second-line therapy was longer in patients who received longer duration of prior therapy, although not significant in the sunitinib-to-axitinib sequence subgroup; OS was also longer in patients with smaller tumour burden, but not significant in the cytokine-to-axitinib sequence subgroup. Safety profiles differed modestly by type and duration of prior therapy.

CONCLUSIONS

AXIS data suggest that longer duration of the first-line therapy generally yields better outcome with the second-line therapy and that lack of response to first-line therapy does not preclude positive clinical outcomes with a second-line vascular endothelial growth factor-targeted agent in patients with advanced RCC.

Phase II study of oxaliplatin, docetaxel, and sargramostim (GM-CSF) in patients with previously treated advanced melanoma

8570

Background: Although much focus has been placed on immunotherapy for melanoma, further development of chemotherapy approaches is needed. Melanoma is responsive to platinum compounds and taxanes, but there is limited experience with combinations of these agents. Oxaliplatin has been reported to have detectable activity in melanoma, and a phase I study has identified a tolerable dose and schedule of oxaliplatin in combination with docetaxel and hematopoietic growth factor support. GM-CSF has a theoretical advantage of immune potentiation. These considerations supported study of oxaliplatin, docetaxel, and GM-CSF in patients with advanced melanoma. Methods: Eligibility included intact organ function, PS=2, at most one prior chemotherapy and one prior immunotherapy, no prior treatment with oxaliplatin or taxanes, and no chremophor allergy. After premedication, docetaxel was administered day 1 at 85 mg/m2, then oxaliplatin on day 2 at 85 mg/m2. GM-CSF (5 μg/kg) was administered s.c. days 3–12. Cycles were 21 days in length, and disease reevaluation was performed every 2 cycles by RECIST criteria. Results: 20 patients were enrolled, 13 with 1 prior therapy, 5 with 2 prior therapies, and 2 previously untreated. Six patients did not complete 2 cycles and were not formally evaluable for response. One patient who failed 2 prior treatment regimens experienced a minor response and received 10 cycles of therapy, and 4 patients had stable disease. The rest showed PD after 2 cycles. Notable toxicities included 7 cases of grade III/IV neutropenia and 2 hypersensitivity reactions. Conclusions: This combination of oxaliplatin, docetaxel, and GM-CSF has limited clinical activity in previously treated patients with advanced melanoma. Exploration in treatment-naive patients may still be warranted.

No significant financial relationships to disclose.

First-line treatment with bevacizumab (B) and high dose (HD) bolus aldesleukin (IL-2) in metastatic renal cell carcinoma (mRCC) patients (Pts)

15524

Background: The rationale for combining HD IL-2 with B includes potential synergistic immune interactions, non-overlapping toxicities, and potential for added clinical benefit. We have initiated a multi-center phase II study designed to estimate the efficacy of combination therapy of standard HD IL-2 and B therapy in mRCC pts. Methods: Pts with histologically confirmed mRCC, predominantly clear cell histology, measurable or evaluable disease, KPS of =80%, adequate end organ function for HD IL-2, and no underlying coagulopathy or thrombotic event are eligible for this study. One cycle consists of 84 days. B (10 mg/kg) IV is given every 2 wks beginning 2 wks prior to the first dose of IL-2. B is dosed 1 hr prior to initiating IL-2 on days IL-2 is given. HD IL-2 (600,000 IU/kg) IV Q8 hours (maximum 28 doses) is given during two 5-day courses separated by 9 days (starting on day 15 and 29). Results: We report the results of the first 15 of a planned 60 pts. The median age is 54 (range 40–73) with 9 men and 6 women. 14 pts have a MSKCC intermediate prognostic score, one pt has a poor prognostic score. In the first cycle, the median number of B doses was 7 of a planned 7 (range 2–7) and the median number of IL-2 doses was 17 of a planned 28 (range 6–26). There has been one treatment related death from unresponsive hypotension which occurred during the second cycle. Typical IL-2 toxicities have been noted thus far. Among a variety of correlative studies, we evaluated the serum L- ornithine (L-O) level, a byproduct of arginase-mediated arginine metabolism that has been shown to inversely correlate with TCR? chain expression. L-O level are significantly elevated in RCC pts possibly due to VEGF stimulation of arginase production. In 4 patients tested to date, peripheral blood L-O levels have dramatically decreased over the course of therapy. Conclusions: HD IL-2 and B can be given safely and may impact on immune regulatory pathways.

[Table: see text]

Pilot study of paclitaxel and carboplatin (P/C) with concurrent radiation therapy (RT) in high risk salivary gland carcinomas (SGC)

15538

Background: Standard therapy for high risk SGC includes surgical resection with adjuvant RT, but a high risk of recurrence exists. The role of chemotherapy in this setting has not been fully defined. Methods: This limited institution pilot study evaluated the use of P/C with concurrent RT as adjuvant treatment of high risk SGC. The primary objective was to assess toxicity of this treatment in anticipation of a larger cooperative group phase II study. Eligible patients (pts.) had a Southwest Oncology Group (SWOG) performance status (PS) of 0–2 who after surgical resection of their SGC had high risk features including positive surgical margins, perineural invasion, multiple lymph node (LN) metastases, or extracapsular extension. Treatment included P = 40 mg/m2 intravenously followed by C = AUC of 2 concurrently on days 1, 8, 15, 22, 29, 36 of RT. RT consisted of a total dose of 60 Gy in 30 fractions to the primary and regional LN sites of disease. Results: Five pts. were enrolled 4 with adenoid cystic CA and 1 with high grade mucoepidermoid CA. Median age was 59 years (32–69), all with SWOG PS = 0. Four pts. completed the full 6 cycle P/C chemotherapy; all completed RT per protocol. Grade III/IV mucositis, the most common toxicity, occurred in 6 of 30 (20%) P/C cycles, leading to alteration of therapy in 1 pt. There was no reported neuropathy or significant laboratory abnormalities. Median follow up was 17.5 months (mos.); most were disease free at last follow up (13 to 37 mos.); 1 recurred at 14 mos.; this pt. accounts for the only death observed. One year survival was 100%. Conclusions: The regimen of P/C with concurrent RT, as defined, was tolerated well. Grade III/IV mucositis was the main toxicity. Based on the overall tolerability of this regimen, we believe that this postoperative combined modality therapy deserves further study in a larger cooperative group phase II trial to further define its toxicity and efficacy in high risk SGC. We thank Bristol Myers Squibb for support of this study.

No significant financial relationships to disclose.

A multicenter phase II study of thalidomide in combination with interleukin-2 (IL-2) in patients with previously untreated metastatic renal cell carcinoma (MRCC)

14636

Background: Thalidomide, a drug with immune modulating and anti-angiogenic properties has shown activity in relapsed/refractory MRCC; furthermore, early phase I data of oral thalidomide with subcutaneous low-dose IL-2 showed the combination to be safe. The potential anti-tumor activity of this combination formed the basis of this study. Methods: The aim of this multi-center, open label, phase II study was to determine the efficacy and safety of thalidomide and IL-2 given in combination. Patients (pts) with untreated clear cell MRCC with measurable disease and previous nephrectomy were eligible. Two 6-week cycles of thalidomide and IL-2 were planned. Each cycle consisted of thalidomide started at 200 mg orally daily and titrated to 400 mg daily on the 4th day for 6 weeks; IL-2 was started one week post initiation of thalidomide at a dose of 7mIU/m2 subcutaneously days 1–5 for 4 weeks, followed by 2 weeks off therapy. Therapy was to be continued until progression, if there was at least stable disease (SD). Planned accrual was 53 patients. Results: 11 pts were enrolled. The trial was terminated early due to lack of responses. Median age was 57 years (51–66). All pts had an Eastern Cooperative Oncology Group performance status of 2 or better. The only grade 3 toxicities were fatigue (3 pts), neuropathy (1 pt), anorexia (1 pt), dyspnea (1 pt), edema (1 pt); these required dose reductions as per protocol. There were no objective responses: 3 pts had SD, 8 pts had progressive disease (PD). The 3 pts with SD completed 4, 4, and 6 cycles of therapy respectively; of the 8 pts with PD, 3 completed two cycles, and 5 completed one cycle of therapy. Conclusions: The combination of thalidomide and low-dose IL-2 was well tolerated, but in this trial did not show anti-tumor activity in patients with clear cell MRCC. We thank Celgene for support of this trial.

No significant financial relationships to disclose.

Digital image capture and quantification of subtle lens opacities in rodents

A rapid, sensitive, and cost-effective method is reported for the subjective and objective documentation of subtle opacities in lenses of unanesthetized transgenic mice or selenite-injected rat pups as models for cataract formation. Animal eyes were dilated with eye drops and the animal was positioned in front of a Nikon FS2 photo slit lamp. Slit-lamp observations were recorded using a Canon Optura Pi digital video recorder. High-quality images of opacifying lenses were captured from the video and quantified using densitometry at progressive stages of opacification. In mice, targeted genomic deletion of the proteins CP49 (a lens-specific filament) or Six5 (a model for myotonic dystrophy) resulted in subtle cataracts that were easily recorded and quantified using this instrumentation. In rats, the early progressive changes leading to a dense nuclear opacity caused by selenite injection were easily documented using this instrumentation. Low-cost components combined with a conventional slit-lamp ophthalmoscope were used to capture high-quality images of selected stages of cataract formation for quantitative analysis using commercial software.

A multi-institutional phase II trial of a novel inpatient schedule of continuous interleukin-2 with interferon alpha-2b in advanced renal cell carcinoma: major durable responses in a less highly selected patient population

BACKGROUND

A prospective multi-institutional phase II trial was undertaken to define the activity and toxicity of a unique decrescendo infusion of interleukin-2 (IL-2) in combination with interferon (IFN) in patients with metastatic renal cell carcinoma. The identical regimen has shown promise in advanced melanoma.

PATIENTS AND METHODS

Between February 1997 and March 1999, 47 patients with metastatic renal cell carcinoma, from five institutions, were treated with outpatient s.c. IFN (10 mU/m2/day) on days 1-5, followed by inpatient IL-2 via continuous i.v. decrescendo infusion [18 million International Units (MIU) (I mg)/m2/6 h, followed by 18 MIU/m2/12 h, then 18 MIU/m2/24 h and 4.5 MIU/m2/24 h for the following 3 days] on days 8-12, in a hospital ward without intensive care unit (ICU)-type monitoring. Treatment was repeated every 4 weeks. In contrast to high dose IL-2 protocols, patient eligibility did not require pulmonary function tests and allowed serum creatinine up to 2 mg/dl.

RESULTS

Among 44 eligible patients, 57% (25) had their primary in place, 57% (25) had bone or visceral involvement, and only 4% (2) had lung as their only site of disease. The overall response rate in 43 response-evaluable patients was 16.3% [95% confidence interval (CI) 5.3 to 27.3], with three complete responses and four partial responses observed. The median survival was 13 months; nine patients remain alive at >23 months. The median duration of response is 36 months (range 11.5 to 48+ months). Toxicity was modest, consisting of typical cytokine-induced systemic symptoms and rare organ dysfunction. Severe grade 4 toxicity occurred in only 13% of the 130 cycles.

CONCLUSIONS

This unique, reasonably well tolerated IL-2/IFN combination induced a modest response rate with a number of durable remissions. While the optimal IL-2-based regimen for the treatment of advanced renal cell carcinoma remains elusive, the present regimen should attract considerable interest. This is based on tumor activity very similar to high dose IL-2 in a patient population not as carefully selected for optimal organ function.

Phase II evaluation of paclitaxel in combination with carboplatin in advanced head and neck carcinoma

BACKGROUND

Two-thirds of patients with squamous cell carcinomas of the head and neck (SCCHN) at diagnosis have advanced disease with projected 5-year survival rates of 30%. In those patients with distant metastatic or previously treated recurrent disease, response rate to the standard regimen of cisplatin and 5-fluorouracil is approximately 30%. The authors investigated the use of paclitaxel and carboplatin in a limited Phase II study in recurrent or metastatic SCCHN to evaluate tumor response, time to progression, survival, and toxicities of this regimen.

METHODS

Patients with recurrent or metastatic SCCHN not amenable to further surgical or radiation therapy were treated with 200 mg/m(2) by 3-hour infusion of paclitaxel followed by carboplatin at an area under the concentration time curve of 6 mg/mL/minute via a 20-30-minute infusion every 3 weeks.

RESULTS

Thirty-seven patients were enrolled. Ninety-five percent of patients had received prior surgery and postoperative radiotherapy. The overall response rate was 27% (95% confidence interval, 13-41%) with 1 complete and 9 PRs. Median survival of all patients was 4.9 months, and 1-year survival rate was 16%. There was a 43% response rate and 15.7-month median survival rate in patients with only distant metastatic disease and 38% response rate and a 4.5-month median survival in patients with locoregional and metastatic disease. The response rate for patients with only locoregional recurrence was 7% with a median survival of 4.8 months. Grade 3-4 myelotoxicity occurred in 24% of cycles administered. There were two treatment-related deaths due to neutropenic fever and one additional death on study may have been caused by treatment-induced thrombocytopenia.

CONCLUSIONS

The combination of paclitaxel and carboplatin is significantly myelotoxic and ineffective in patients with previously treated locoregionally recurrent SCCHN, whereas it deserves further evaluation in those patients with distant metastatic disease alone. In those patients with locoregional disease, other more innovative treatments are needed.

Pilot study of sequential vinorelbine and cisplatin followed by docetaxel for selected IIIB and stage IV non-small cell lung cancer

Vinorelbine, cisplatin and docetaxel are known to be efficacious in non-small cell lung cancer (NSCLC). This limited institution pilot study evaluated the novel strategy of sequencing active first line agents prior to progression. The primary objective of this study was to assess the toxicity profile in anticipation of a larger cooperative group standard phase II study. Patients with selected stage IIIB and IV NSCLC, Southwest Oncology Group (SWOG) performance status (PS) of 1 or less and measurable or evaluable disease were eligible. Treatment was cisplatin 100 mg/m(2) day 1 and 29, vinorelbine 25 mg/m(2) weekly for 8 weeks, followed by docetaxel 100 mg/m(2) every 21 days for four cycles if no progression. If grade IV neutropenia developed, G-CSF 5 mcg/kg/day was used in subsequent cycles. Of 18 eligible patients, 17 patients had stage IV disease with a median age of 66 years (range 48-80). Eight patients had a SWOG PS of 1, 10 had a PS of zero. Six of eighteen patients received all 8 weeks of vinorelbine/cisplatin and six of eight patients who went on to receive docetaxel received all four planned cycles; only two patients overall received all planned therapy. One grade III/IV event each of cardiotoxicity (myocardial infarction), renal toxicity (acute renal failure), anemia and thrombocytopenia occurred with vinorelbine and cisplatin, and 2 Grade IV hypersensitivity reactions, manifested by severe back pain with docetaxel occurred. Three deaths occurred during the study, all during treatment with vinorelbine and cisplatin: one due to neutropenic sepsis; one from a pulmonary embolism; and one secondary to severe hypoglycemia in a diabetic patient. Of the 16 patients evaluable for response after vinorelbine/cisplatin, there were two complete responses (12.5%) and three partial responses (19%) for an overall response rate of 31% (95% CI 8-58). One additional patient who received docetaxel experienced a partial response. Two patients remain alive (21+ and 18+ months, respectively). The 1-year survival was 44%.

CONCLUSION

This sequence, as defined, was tolerated marginally well in patients with advanced NSCLC. Granulocytopenia was the major toxicity requiring dose adjustments throughout the sequence. Based on response rates and tolerability that were somewhat comparable to other regimens in this disease setting, a modified version of this program, adjusted to decrease the incidence of grade III and IV toxicity, was selected as one arm of a recent randomized phase II trial in the Southwest Oncology Group (SWOG), S9806, evaluating sequential therapy in advanced NSCLC.

Metanephric adenosarcoma in a young adult: morphologic, immunophenotypic, ultrastructural, and fluorescence in situ hybridization analyses: a case report and review of the literature

Metanephric neoplasms are uncommon renal tumors that arise in both children and adults. They may be composed of small epithelial cells or benign stroma, or both, and are termed metanephric adenoma, metanephric stromal tumor, or metanephric adenofibroma, respectively. Thus far, these tumors have been known for their benign behavior. We present the case of a 21-year-old woman who developed a neoplasm composed of a renal epithelial component identical to metanephric adenoma combined with a malignant spindle cell sarcoma. The epithelial component was positive for pankeratin AE1/3, whereas the sarcomatous component was negative for epithelial markers and positive for vimentin, CD34, and CD117. No smooth muscle differentiation was apparent in the sarcoma by immunohistochemistry or ultrastructural analysis. By fluorescent in situ hybridization analysis of the sarcomatous component there was monosomy of the X chromosome, but no apparent variation from the normal diploid pattern for chromosomes 3, 7, 12, and 17. We conclude that the spectrum of metanephric neoplasia should be expanded to include malignant stromal variants, and we propose the term "metanephric adenosarcoma" for the present case.

Phase IB study of 25-hydroxyvitamin D(3) treatment to diminish suppressor cells in head and neck cancer patients

Patients with head and neck squamous cell carcinoma (HNSCC) have profound immune defects. These defects are associated with a poor prognosis and are mediated, in part, by an increased number of immune inhibitory CD34(+) progenitor cells in their peripheral blood and tumor. The CD34(+) cells suppress autologous T-cell functions. Our prior work had shown that the differentiation inducer 1alpha,25-dihydroxyvitamin D(3) could drive the differentiation of CD34(+) cells isolated from HNSCC patients into dendritic cells. A phase IB clinical trial was initiated with HNSCC patients to determine if 25-hydroxyvitamin D(3) treatment could diminish CD34(+) cell levels and improve immune function. Six patients per treatment group were orally administered 20 or 40 microg/day 25-hydroxyvitamin D(3) for six weeks. Peripheral blood was collected at 0, 1, 2, 4, 6, and 8 weeks, and assessed for markers of immune activity. Although no clinical responses were observed, results of these pilot studies showed that 25-hydroxyvitamin D(3) reduced the presence of immune suppressive CD34(+) cells and improved immune competence of HNSCC patients.

Outpatient biochemotherapy with interleukin-2 and interferon alfa-2b in patients with metastatic malignant melanoma: results of two phase II cytokine working group trials

PURPOSE

The Cytokine Working Group performed a randomized phase II trial of two outpatient biochemotherapy regimens to identify an outpatient regimen with high antitumor activity and less toxicity than inpatient regimens which might be compared with chemotherapy or inpatient biochemotherapy regimens in future phase III trials.

PATIENTS AND METHODS

Eighty-one patients with metastatic malignant melanoma received dacarbazine 250 mg/m(2)/d intravenously (IV) and cisplatin 25 mg/m(2)/d IV on days 1, 2, and 3, plus interferon (IFN) alfa-2b 5 mU/m(2) subcutaneously (SC) on days 6, 8, 10, 13, and 15, given every 28 days. Interleukin-2 (IL-2) was given daily on days 6 to 10 and 13 to 15. In group 1, IV IL-2 was given at 18.0 MU/m(2), and in group 2, SC IL-2 was given at 5.0 mU/m(2).

RESULTS

In group 1 (IV IL-2), there were five complete responses (CRs) and 11 partial responses (PRs) among 44 patients (objective response rate [ORR], 36%; 95% confidence interval [CI], 22% to 51%). In group 2 (SC IL-2), there was one CR and five PRs among the 36 patients (ORR, 17%; 95% CI, 4% to 29%). The median survival was 10.7 months in group 1 and 7.3 months in group 2. Eleven patients in group 1 and four patients in group 2 remain alive as of the last follow-up. Toxicities in both groups were similar. No patient required hospitalization for neutropenic fever.

CONCLUSION

Biochemotherapy has activity in these outpatient regimens with acceptable toxicity. The antitumor activity observed with the IV IL-2 regimen seems similar to that of inpatient biochemotherapy regimens. If inpatient biochemotherapy regimens develop an established role in the management of melanoma, future phase III trial comparisons with this outpatient IV IL-2 regimen would be appropriate.

Glucocorticoid induction of the glaucoma gene MYOC in human and monkey trabecular meshwork cells and tissues

PURPOSE

To examine the intracellular and extracellular expression of myocilin in the human and primate trabecular meshwork (TM) in the presence and absence of glucocorticoids.

METHODS

Myocilin expression was examined in cultured human TM cells by Northern blot analysis and myocilin antibody-mediated immunoprecipitation. Myocilin expression was quantified using high-resolution two-dimensional polyacrylamide gel electrophoresis of radiolabeled proteins from human TM cells, TM tissue explants, and perfused human anterior segments cultured with and without dexamethasone (DEX) for 14 to 21 days, as well as TM tissue from pigtailed monkeys treated orally for 1 year with cortisone acetate. Immunofluorescence with anti-myocilin antibodies was used to localize cellular and extracellular expression of myocilin in cultured human TM cells.

RESULTS

Glucocorticoid treatment caused a significant induction of myocilin mRNA, a tetrad of cell-associated proteins, and 8 to 20 secreted proteins (molecular mass [M(r)] 56 and 59 kDa and isoelectric point [pI] 5.2 and 5.3) in some, but not all the cultured human TM cells and explanted tissues. Western immunoblot analysis using anti-myocilin peptide antibodies identified these proteins as encoded by the MYOC gene. There was significant induction of the myocilin proteins in three perfusion-cultured human eyes, in which DEX-induced elevated intraocular pressure developed. Monkeys treated 1 year with cortisol acetate showed steroid glaucoma-like morphologic changes in the TM that correlated with the induction of myocilin in the TM. Immunofluorescence analysis of cultured TM cells localized myocilin intracellularly in discrete perinuclear and cytoplasmic vesicular deposits as well as extracellularly on the cell surface associated with the extracellular matrix. In several DEX-treated TM cell lines, there were significant levels of myocilin secreted into the media. Enzymatic deglycosylation of proteins in the TM media converted the higher molecular weight isoforms of myocilin (approximately 57 kDa) to the lower molecular weight isoforms ( approximately 55 kDa).

CONCLUSIONS

Although the function of myocilin is unknown, induction of these TM proteins was found in eyes in which glucocorticoid-induced ocular hypertension developed. Therefore, myocilin may play an important pathogenic role in ocular hypertension in addition to its role in certain forms of POAG.

Fourier and power law analysis of structural complexity in cornea and lens

The ordered pattern of type I collagen fibrils in the transparent cornea is an example of specialization in the formation of functional ultrastructure. In contrast, the disordered and amorphous distribution of cytoplasmic proteins in the transparent lens resembles the structure of most cells. While the organization of cytoplasmic proteins is often considered to be random, the compartmentalization of functional proteins in biological cells and the organization provided by cytoskeletal elements suggests that non-random patterns of organization are common. Attempts to quantify disordered, amorphous patterns of ultrastructure in cells and tissues have been unsuccessful, in part, because the cellular organization of structural proteins including collagen, keratin, cytoskeletal and crystallin proteins is complex. Characterization of the complex patterns observed in electron micrographs is a fundamental problem in structural biology. This paper reviews the use of Fourier and power law analyses of electron micrographs of cornea and lens as models for ordered and disordered ultrastructure of cells and tissues.

Chaperone function of mutant versions of alpha A- and alpha B-crystallin prepared to pinpoint chaperone binding sites

A major stress protein, alpha-crystallin, functions as a chaperone. Site-directed mutagenesis has been used to identify regions of the protein necessary for chaperone function. In this work we have taken some of the previously described mutants produced and assessed their chaperone function by both a traditional heat-induced aggregation method at elevated temperature and using enzyme methods at 37 degrees C. In general the different assays gave parallel results indicating that the same property is being measured. Discrepancies were explicable by the heat lability of some mutants. Most mutants had full chaperone function showing the robust nature of alpha-crystallin. A mutant corresponding to a minor component of rodent alpha A-crystallin, alpha Ains-crystallin, had decreased chaperone function. Decreased chaperone function was also found for human Ser139--> Arg, Thr144-->Arg, Ser59-->Ala mutants of alpha B-crystallin and double mutants Ser45-->Ala/Ser59-->Ala, Lys103--> Leu/His104-->Ile, and Glu110-->His/His111-->Glu. A mutant Phe27-->Arg that was the subject of previous controversy was shown to be fully active at physiological temperatures.

Three distinct stages of lens opacification in transgenic mice expressing the HIV-1 protease

Scanning electron microscopy of the lenses from transgenic mice (TG(72)) containing the HIV-1 protease linked to the lens alphaA-crystallin promoter showed structural changes around postnatal day 16. Frank opacification of the lens was observed at day 24. To relate the biochemical and biophysical changes that occur during the process of cataract development, high-resolution two-dimensional gel electrophoresis (2D), quantitative image analysis and ion measurements were carried out on lenses from postnatal day 10 and on days 15-24. The phase separation temperature (Tc), a measure of molecular interactions between proteins, was also determined for normal and transgenic lenses. A comparison of the transgenic and normal lenses on day 10 revealed no significant differences in any of the measured parameters. However, starting around day 16 or the first stage of observed structural changes, the TG(72)crystallin profiles of the alphaA- alphaB-, betaA3-, betaA4-, betaB3 and one gamma-crystallin began to deviate from the normal. By postnatal day 20, a second stage was initiated with an influx of calcium and sodium ions that was accompanied by modifications of betaB1- and betaB2-crystallin. In the third and final stage of the cataract process, a large increase in the proteolysis of crystallins was accompanied by the appearance of the frank cataract on day 24. The Tc initially increased in all of the mouse lenses until just prior to eyelid opening. After that time, the Tc decreased in all lenses. Although the Tc continued to decrease in the normal lenses with age, for the homozygous transgenic mice it exhibited a dramatic increase that began on day 20. Thus, in the TG(72)transgenic mouse, cataract formation occurs in a three-stage process. Tc and other biophysical parameters previously measured appeared to be insensitive to the modifications that occur during stage 1. However, during the second stage of cataract formation, there was a correspondence between abnormal Tc and the abnormal interactions between cellular constituents apparently resulting from lens hydration, the loss of ion homeostasis and continued proteolysis. The last stage of cataract formation results in a total loss of lens transparency and leakage of lens proteins.

Dendritic cells transduced with full-length wild-type p53 generate antitumor cytotoxic T lymphocytes from peripheral blood of cancer patients

Accumulation of wild-type or mutant p53 protein occurs in approximately 50% of human malignancies. This overexpression may generate antigenic epitopes recognized by CTLs. Because normal cells have undetectable levels of p53, these CTLs are likely to be tumor specific. Here, for the first time, we test the hypothesis that full-length wild-type p53 protein can be used for generation of an immune response against tumor cells with p53 overexpression. T cells obtained from nine HLA-A2-positive cancer patients and three HLA-A2-positive healthy individuals were stimulated twice with dendritic cells (DCs) transduced with an adenovirus wild-type p53 (Ad-p53) construct. Significant cytotoxicity was detected against HLA-A2-positive tumor cells with accumulation of mutant or wild-type p53 but not against HLA-A2-positive tumor cells with normal (undetectable) levels of p53 or against HLA-A2-negative tumor cells. This response was specific and mediated by CD8+ CTLs. These CTLs recognized HLA-A2-positive tumor cells expressing normal levels of p53 protein after their transduction with Ad-p53 but not with control adenovirus. Stimulation of T cells with Ad-p53-transduced DCs resulted in generation of CTLs specific for p53-derived peptide. These data demonstrate that DCs transduced with the wild-type p53 gene were able to induce a specific antitumor immune response. This offers a new promising approach to immunotherapy of cancer.

Increased production of immature myeloid cells in cancer patients: a mechanism of immunosuppression in cancer

Defective dendritic cell (DC) function caused by abnormal differentiation of these cells is an important mechanism of tumor escape from immune system control. Previously, we have demonstrated that the number and function of DC were dramatically reduced in cancer patients. This effect was closely associated with accumulation of immature cells (ImC) in peripheral blood. In this study, we investigated the nature and functional role of those ImC. Using flow cytometry, electron microscopy, colony formation assays, and cell differentiation in the presence of different cell growth factors, we have determined that the population of ImC is composed of a small percentage (<2%) of hemopoietic progenitor cells, with all other cells being represented by MHC class I-positive myeloid cells. About one-third of ImC were immature macrophages and DC, and the remaining cells were immature myeloid cells at earlier stages of differentiation. These cells were differentiated into mature DC in the presence of 1 microM all-trans-retinoic acid. Removal of ImC from DC fractions completely restored the ability of the DC to stimulate allogeneic T cells. In two different experimental systems ImC inhibited Ag-specific T cell responses. Thus, immature myeloid cells generated in large numbers in cancer patients are able to directly inhibit Ag-specific T cell responses. This may represent a new mechanism of immune suppression in cancer and may suggest a new approach to cancer treatment.

Osteogenic sarcoma associated with Diamond-Blackfan anemia: a report from the Diamond-Blackfan Anemia Registry

PURPOSE

Diamond-Blackfan anemia (DBA) is a congenital pure red cell aplasia, usually presenting in infancy or early childhood. A review of the literature strongly supports a predisposition to hematopoietic malignancy. Recently, solid tumors have been reported, some attributable to hemosiderosis and/or androgen therapy. Two cases of osteogenic sarcoma have also been documented. An analysis from the Diamond-Blackfan Anemia Registry was performed to evaluate the cancer risk in patients with DBA.

METHODS

The Diamond-Blackfan Anemia Registry of North America (DBAR) is a comprehensive database of patients with DBA enrolled, after informed consent, through outreach to pediatric hematologists and family groups. The patients and/or their families complete a detailed questionnaire, and a review of medical records and telephone interviews are performed to complete and clarify the information provided.

RESULTS

Of the 354 patients registered in the DBAR, there were six patients meeting the accepted diagnostic criteria for DBA who were found to have malignancies. Three patients had osteogenic sarcoma diagnosed, one with myelodysplastic syndrome, one with colon carcinoma, and one with a soft tissue sarcoma.

CONCLUSION

There appears to be an association of osteogenic sarcoma with DBA. A young age at presentation may be a feature of DBA-associated osteogenic sarcoma. Because of the immaturity of the database, the actuarial risk for osteogenic sarcoma and other cancers in individuals with DBA cannot be ascertained. Speculation is made regarding the nature of the molecular defect leading to the association of DBA and osteogenic sarcoma.

New therapeutic strategies for the treatment and prevention of head and neck cancer

Head and neck squamous cell carcinoma (HNSCC) is an aggressive epithelial malignancy that is now the sixth most common neoplasm in the world today. Approximately 50,000 cases in the United States and more than 500,000 cases worldwide will be diagnosed in 2000 [1]. Despite numerous advances in treatment utilising the most recent protocols for surgery, radiation and chemotherapy, the long-term survival has remained at less than 50% over the past 40 years [2]. This poor long-term survival is due to a number of variables including delayed diagnosis as well as the frequent development of multiple primary tumours. Therefore, in addition to early detection, continued emphasis must be placed on preventing the development of new primaries as well as establishing more effective treatments for individuals who present with advanced disease. This review will summarise some of the recent advances in the realms of chemotherapy and radiation therapy. In addition, it will discuss the present status of chemoprevention in HNSCC. Finally, we will discuss the rationale for the use of anti-angiogenic agents as one possible means of developing new chemopreventive protocols that result in reduced toxicity while maintaining similar clinical efficacies.

Lenses of SPARC-null mice exhibit an abnormal cell surface-basement membrane interface

SPARC (secreted protein acidic and rich in cysteine) is a matricellular protein involved in cell-matrix interactions. We have shown previously that mice deficient in SPARC develop posterior cortical cataract early in life that progresses to a mature opacity and capsule rupture. To evaluate the primary effects of SPARC deficiency in the lens, we examined the lenses of SPARC-null and wild-type mice by electron microscopy and immunohistochemistry to investigate whether ultrastructural abnormalities occur at the basement membrane (capsule)-lens cell interface in SPARC-null mice. The most notable feature in the lenses of SPARC-null mice, relative to wild-type animals, was the modification of the basal surface of the lens epithelial and fiber cells at the basement membrane (capsule) interface. Electron microscopy revealed numerous filopodial projections of the basal surface of the lens epithelial and fiber cells into the extracellular matrix of the anterior, posterior, and equatorial regions of the lens capsule. In 1 week old precataractous lenses, basal invasive filopodia projecting into the capsule were small and infrequent. Both the size and frequency of these filopodia increased in precataractous 3-4 week old lenses and were prominent in the cataractous 5-6 week old lenses. By rhodamine-phalloidin labeling, we confirmed the presence of basal invasive filopodia projecting into the lens capsule and demonstrated that the projections contained actin filaments. In contrast to the obvious abnormal projections at the interface between the basal surface of the lens epithelial and fiber cells and the lens capsule, the apical and lateral plasma membranes of lens epithelial cells and lens fibers in SPARC-null mice were as smooth as those of wild-type mice. We conclude that the absence of SPARC in the murine lens is associated with a filopodial protrusion of the basal surface of the lens epithelium and differentiating fiber cells into the lens capsule. The altered structures appear prior to the opacification of the lens in the SPARC-null model. These observations are consistent with one or more functions previously proposed for SPARC as a modulator of cell shape and cell-matrix interactions.

Expression and characterization of SPARC in human lens and in the aqueous and vitreous humors

SPARC (secreted protein, acidic and rich in cysteine) is a matricellular glycoprotein that regulates morphogenesis, cellular proliferation, and differentiation. SPARC is a critical factor in the development and maintenance of lens transparency in mice. SPARC-null mice develop lenticular opacity at an early age that progresses gradually to mature cataract. Despite the high level of homology between the mouse and human genes, little is known about SPARC in the human lens. We have studied the expression of SPARC protein in human lens and surrounding ocular tissues from normal human donors (60-70 years old). Immunohistochemical and immunoblot analyses were conducted on lens, aqueous humor, vitreous, ciliary epithelium, pigment epithelium, cornea and retina. The epithelia and capsule of the lens contained SPARC, whereas the cortical and nuclear fibers did not. In contrast, the aqueous humor and vitreous, which provide nutrients to the lens and regulate its development and function, contained significant amounts of SPARC. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis of extracts of various ocular tissues revealed bands of 43 and 29 kD after disulfide bond reduction that were reactive with anti-SPARC IgG. Despite the presence of protease inhibitors during sample preparation, we observed cleavage of intact SPARC to a 29 kD fragment, a peptide reported in other tissues and attributed to endogenous proteolysis. In addition, bands of molecular mass 150 and 200 kD were present that appeared to be disulfide-bonded complexes of SPARC monomers. Human cornea, ciliary epithelium, pigment epithelium and retina also contained SPARC. The presence of SPARC in the aqueous humor and vitreous, as well as in the lens, indicates a functional importance of SPARC in adult human eye as well as in lens development.

Clinical significance of defective dendritic cell differentiation in cancer

Defective dendritic cell (DC) function has been described previously in cancer patients and tumor-bearing mice. It can be an important factor in the escape of tumors from immune system control. However, the mechanism and clinical significance of this phenomenon remain unclear. Here, 93 patients with breast, head and neck, and lung cancer were investigated. The function of peripheral blood and tumor draining lymph node DCs was equally impaired in cancer patients, consistent with a systemic rather than a local effect of tumor on DCs. The number of DCs was dramatically reduced in the peripheral blood of cancer patients. This decrease was associated with the accumulation of cells lacking markers of mature hematopoietic cells. The presence of these immature cells was closely associated with the stage and duration of the disease. Surgical removal of tumor resulted in partial reversal of the observed effects. The presence of immature cells in the peripheral blood of cancer patients was closely associated with an increased plasma level of vascular endothelial growth factor but not interleukin 6, granulocyte macrophage colony-stimulating factor, macrophage colony-stimulating factor, interleukin 10, or transforming growth factor-beta and was decreased in lung cancer patients receiving therapy with antivascular endothelial growth factor antibodies. These data indicate that defective DC function in cancer patients is the result of decreased numbers of competent DCs and the accumulation of immature cells. This effect may have significant clinical implications.

Mice deficient in Six5 develop cataracts: implications for myotonic dystrophy

Expansion of a CTG trinucleotide repeat in the 3' UTR of the gene DMPK at the DM1 locus on chromosome 19 causes myotonic dystrophy, a dominantly inherited disease characterized by skeletal muscle dystrophy and myotonia, cataracts and cardiac conduction defects. Targeted deletion of Dm15, the mouse orthologue of human DMPK, produced mice with a mild myopathy and cardiac conduction abnormalities, but without other features of myotonic dystrophy, such as myotonia and cataracts. We, and others, have demonstrated that repeat expansion decreases expression of the adjacent gene SIX5 (refs 7,8), which encodes a homeodomain transcription factor. To determine whether SIX5 deficiency contributes to the myotonic dystrophy phenotype, we disrupted mouse Six5 by replacing the first exon with a beta-galactosidase reporter. Six5-mutant mice showed reporter expression in multiple tissues, including the developing lens. Homozygous mutant mice had no apparent abnormalities of skeletal muscle function, but developed lenticular opacities at a higher rate than controls. Our results suggest that SIX5 deficiency contributes to the cataract phenotype in myotonic dystrophy, and that myotonic dystrophy represents a multigenic disorder.

[Analysis of cytoskeletal proteins in rat selenium cataract using two-dimensional electrophoresis]

BACKGROUND AND PURPOSE

Previous studies used sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) to characterize the modifications to lens proteins during opacification in the selenite model for cataract. To analyze the protein modifications in more detail, two dimensional electrophoresis (2 DE), which is more sensitive than 1 D electrophoresis, was used.

RESULTS

The results of 2 DE demonstrated rapid changes in cytoskeletal proteins including spectrin and vimentin at the earliest stages of opacification.

CONCLUSION

The results suggested that the mechanism of opacification might involve changes in cytoskeletal proteins during the earliest stages of cataract formation.

Fibroblast growth factor-2 selectively stimulates angiogenesis of small vessels in arterial tree

There is a critical need for quantifiable models of angiogenesis in vivo, and in general, differential effects of angiogenic regulators on vascular morphology have not been measured. Because the potent angiogenic stimulators fibroblast growth factor (FGF)-2 (basic FGF) and vascular endothelial growth factor (VEGF) are reported to stimulate angiogenesis through distinct signaling pathways, we hypothesized that FGF-2 stimulates vascular morphology differently than does VEGF and that stimulation of angiogenesis by FGF-2 is directly correlated to FGF receptor density. FGF-2 was applied at embryonic day 7 (E7), E8, or E9 to the quail chorioallantoic membrane (CAM); subsequent response of the arterial tree was measured by the fractal dimension (D(f)), a mathematical descriptor of complex spatial patterns, and by several generational branching parameters that included vessel length density (L(v)). After application of FGF-2 at E7, arterial density increased according to D(f) as a direct function of increasing FGF-2 concentration, and FGF-2 stimulated the growth of small vessels, but not of large vessels, according to L(v) and other branching parameters. For untreated control specimens at E7, L(v) of small vessels and D(f) were 11.1+/-1.6 cm(-1) and 1.38+/-0.01, respectively; at E8, after treatment with 5 microgram FGF-2/CAM for 24 hours, L(v) of small vessels and D(f) increased respectively to 22.8+/-0.7 cm(-1) and 1. 49+/-0.02 compared with 16.3+/-0.9 cm(-1) and 1.43+/-0.02 for PBS-treated control specimens. Application of FGF-2 at E8 and E9 did not significantly increase arterial density. By immunohistochemistry, the expression of 4 high-affinity tyrosine kinase FGF receptors was significantly expressed at E7, when CAM vasculature responded strongly to FGF-2 stimulation, but FGF receptor expression decreased throughout the CAM by E8, when vascular response to FGF-2 was negligible. In conclusion, the "fingerprint" vascular pattern elicited by FGF-2 was distinct from vascular patterns induced by other angiogenic regulators that included VEGF(165), transforming growth factor-beta1, and angiostatin.

Generational analysis reveals that TGF-beta1 inhibits the rate of angiogenesis in vivo by selective decrease in the number of new vessels

Quantitative analysis of vascular generational branching demonstrated that transforming growth factor-beta1 (TGF-beta1), a multifunctional cytokine and angiogenic regulator, strongly inhibited angiogenesis in the arterial tree of the developing quail chorioallantoic membrane (CAM) by inhibition of the normal increase in the number of new, small vessels. The cytokine was applied uniformly in solution at embryonic day 7 (E7) to the CAMs of quail embryos cultured in petri dishes. After 24 h the rate of arterial growth was inhibited by as much as 105% as a function of increasing TGF-beta1 concentration. Inhibition of the rate of angiogenesis in the arterial tree by TGF-beta1 relative to controls was measured in digital images by three well-correlated, computerized methods. The first computerized method, direct measurement by the computer code VESGEN of vascular morphological parameters according to branching generations G(1) through G(>/=5), revealed that TGF-beta1 selectively inhibited the increase in the number density of small vessels, N(v>/=5) (382 +/- 85 cm(-2) for specimens treated with 1 microg TGF-beta1/CAM for 24 h, compared to 583 +/- 99 cm(-2) for controls), but did not significantly affect other parameters such as average vessel length or vessel diameter. The second and third methods, the fractal dimension (D(f)) and grid intersection (rho(v)), are statistical descriptors of spatial pattern and density. According to D(f) and rho(v), arterial density increased in control specimens from 1.382 +/- 0.007 and 662 +/- 52 cm(-2) at E7 (0 h) to 1.439 +/- 0.013 and 884 +/- 55 cm(-2) at E8 (24 h), compared to 1. 379 +/- 0.039 and 650 +/- 111 cm(-2) for specimens treated with 1 microg TGF-beta1/CAM for 24 h. TGF-beta1 therefore regulates vascular pattern and the rate of angiogenesis in a unique "fingerprint" manner, as do other major angiogenic regulators that include VEGF, FGF-2 (bFGF), and angiostatin. TGF-beta1 did not stimulate angiogenesis significantly at low cytokine concentrations, which suggests that this quail CAM model of angiogenesis is not associated with an inflammatory response.

Small heat-shock proteins and their potential role in human disease

The elevated expression of stress proteins is considered to be a universal response to adverse conditions, representing a potential mechanism of cellular defense against disease and a potential target for novel therapeutics, including gene therapy and chaperone-modulating reagents. Recently, a single mutation in the small heat-shock protein human alphaB-crystallin was linked to desmin-related myopathy, which is characterized by abnormal intracellular aggregates of intermediate filaments in human muscle. New findings demonstrate that the high level of expression of stress proteins can contribute to an autoimmune response and can protect proteins that contribute to disease processes.

Lens cytoplasmic phase separation

Cytoplasmic transparency is a unique feature of lens cells. The cytoplasm is a concentrated solution of crystallin proteins with minor constituents that include cytoskeletal proteins and lens specific intermediate filaments. Under normal physiological conditions, the proteins exist as a single transparent phase. With normal aging, progressive modification of the interactions between lens proteins occurs so that conditions within the lens become favorable for phase separation. These conditions produce intracellular inhomogeneities that approach or exceed the dimensions of the wavelength of visible light (400 to 700 nm) and light scattering from lens cells increases. The resulting opacification is the primary factor in the visual loss experienced in cataract, the leading cause of blindness in the world. We study biochemical factors that regulate the cytoplasmic phase separation and maintain normal cellular transparency.

The cardiomyopathy and lens cataract mutation in alphaB-crystallin alters its protein structure, chaperone activity, and interaction with intermediate filaments in vitro

Desmin-related myopathy and cataract are both caused by the R120G mutation in alphaB-crystallin. Desmin-related myopathy is one of several diseases characterized by the coaggregation of intermediate filaments with alphaB-crystallin, and it identifies intermediate filaments as important physiological substrates for alphaB-crystallin. Using recombinant human alphaB-crystallin, the effects of the disease-causing mutation R120G upon the structure and the chaperone activities of alphaB-crystallin are reported. The secondary, tertiary, and quaternary structural features of alphaB-crystallin are all altered by the mutation as deduced by near- and far-UV circular dichroism spectroscopy, size exclusion chromatography, and chymotryptic digestion assays. The R120G alphaB-crystallin is also less stable than wild type alphaB-crystallin to heat-induced denaturation. These structural changes coincide with a significant reduction in the in vitro chaperone activity of the mutant alphaB-crystallin protein, as assessed by temperature-induced protein aggregation assays. The mutation also significantly altered the interaction of alphaB-crystallin with intermediate filaments. It abolished the ability of alphaB-crystallin to prevent those filament-filament interactions required to induce gel formation while increasing alphaB-crystallin binding to assembled intermediate filaments. These activities are closely correlated to the observed disease pathologies characterized by filament aggregation accompanied by alphaB-crystallin binding. These studies provide important insight into the mechanism of alphaB-crystallin-induced aggregation of intermediate filaments that causes disease.

ATP and the core "alpha-Crystallin" domain of the small heat-shock protein alphaB-crystallin

Electrospray ionization mass spectrometry (ESI-LC/MS) of tryptic digests of human alphaB-crystallin in the presence and absence of ATP identified four residues located within the core "alpha-crystallin" domain, Lys(82), Lys(103), Arg(116), and Arg(123), that were shielded from the action of trypsin in the presence of ATP. In control experiments, chymotrypsin was used in place of trypsin. The chymotryptic fragments of human alphaB-crystallin produced in the presence and absence of ATP were analyzed using liquid chromatography-tandem mass spectrometry (LC-MS/MS). Seven chymotryptic cleavage sites, Trp(60), Phe(61), Phe(75), Phe(84), Phe(113), Phe(118), and Tyr(122), located near or within the core alpha-crystallin domain, were shielded from the action of chymotrypsin in the presence of ATP. Chemically similar analogs of ATP were less protective than ATP against proteolysis by trypsin or chymotrypsin. ATP had no effect on the enzymatic activity of trypsin and the K(m) for trypsin was 0.031 mM in the presence of ATP and 0.029 mM in the absence of ATP. The results demonstrated an ATP-dependent structural modification in the core alpha-crystallin domain conserved in nearly all identified small heat-shock proteins that act as molecular chaperones.

Daily subcutaneous ultra-low-dose interleukin 2 with daily low-dose interferon-alpha in patients with advanced renal cell carcinoma

A limited institution Phase II pilot study was performed using a very low-dose combination of daily s.c. interleukin (IL)-2 with IFN-alpha-2b in patients with advanced renal cancer in an attempt to duplicate or increase the response documented with higher dose schedules without the attendant toxicity profile. We selected a dose of IL-2 with documented immunological activity and combined it with clinically active low-dose IFN. Between August 1994 and September 1996, 19 patients with metastatic renal cell carcinoma, who had been judged incapable of tolerating high-dose i.v. IL-2, were treated with IL-2 (1 million units/m2/day) and IFN (1 million units/day), administered s.c. daily. All treatments were administered on an outpatient basis. Virtually all patients had bulky tumor burden with multiple sites of involvement, including five patients with bone metastases. No major objective responses were observed; however, one patient experienced a minor response lasting 13 months, with an associated improvement in performance status. Median survival was 6 months, and 1-year survival was 16%. Toxicity was generally mild and consisted almost entirely of constitutional symptoms. No serious grade 3 or 4 toxicity was observed, although two patients withdrew from treatment due to treatment-related fatigue. On therapy, mild eosinophilia but no lymphocytosis was noted; in fact, peripheral lymphocyte counts decreased, only to rebound after treatment was discontinued. No toxic deaths occurred. Despite the reasonable tolerability of this daily low-dose s.c. regimen, we conclude that this regimen is an ineffective treatment in metastatic renal cell carcinoma patients who are incapable of tolerating high-dose i.v. IL-2.

Site-directed mutations within the core "alpha-crystallin" domain of the small heat-shock protein, human alphaB-crystallin, decrease molecular chaperone functions

Site-directed mutagenesis was used to evaluate the effects on structure and function of selected substitutions within and N-terminal to the core "alpha-crystallin" domain of the small heat-shock protein (sHsp) and molecular chaperone, human alphaB-crystallin. Five alphaB-crystallin mutants containing single amino acid substitutions within the core alpha-crystallin domain displayed a modest decrease in chaperone activity in aggregation assays in vitro and in protecting cell viability of E. coli at 50 degrees C in vivo. In contrast, seven alphaB-crystallin mutants containing substitutions N-terminal to the core alpha-crystallin domain generally resembled wild-type alphaB-crystallin in chaperone activity in vitro and in vivo. Size-exclusion chromatography, ultraviolet circular dichroism spectroscopy and limited proteolysis were used to evaluate potential structural changes in the 12 alphaB-crystallin mutants. The secondary, tertiary and quaternary structures of mutants within and N-terminal to the core alpha-crystallin domain were similar to wild-type alphaB-crystallin. SDS-PAGE patterns of chymotryptic digestion were also similar in the mutant and wild-type proteins, indicating that the mutations did not introduce structural modifications that altered the exposure of proteolytic cleavage sites in alphaB-crystallin. On the basis of the similarities between the sequences of human alphaB-crystallin and the sHsp Mj HSP16.5, the only sHsp for which there exists high resolution structural information, a three-dimensional model for alphaB-crystallin was constructed. The mutations at sites within the core alpha-crystallin domain of alphaB-crystallin identify regions that may be important for the molecular chaperone functions of sHsps.

Lens cytoskeleton and transparency: a model

The function of the cytoskeleton in lens was first considered when cytoplasmic microtubules were observed in elongating fibre cells of the chick lens nearly 40 years ago. Since that time, tubulin, actin, vimentin and intermediate filaments have been identified and found to function in mitosis, motility and cellular morphology during lens cell differentiation. A role for the cytoskeleton in accommodation has been proposed and modification of the cytoskeletal proteins has been observed in several cataract models. Recently, a progressive increase in protein aggregation and lens opacification was found to correspond with the loss of cytoskeletal protein in the selenite model for cataract. In the present report a model is proposed for the role of tubulin, actin, vimentin, spectrin and the lens-specific filaments, filensin and CP49, in the establishment and maintenance of transparent lens cell structure.

Theoretical and experimental basis for the inhibition of cataract

Aggregation of the lens proteins to form high molecular weight clusters is a major contributing factor in age-onset nuclear cataract [Benedek, G. B. (1971) Theory of transparency of the eye. Appl. Optics, 10, 459-473]. This aggregation occurs continually throughout life and contributes to an exponential increase, as a function of age, in the intensity of the light backscattered out of the lens. The time constant deltaT for this exponential increase in human populations is a valuable index, helpful for conducting clinical trials. In-vitro studies have identified reagents capable of inhibiting high molecular weight aggregate formation, as well as the non-covalent interprotein interactions responsible for phase separation. These reagents are also found experimentally to be effective cataract inhibitors in animal model systems in vivo. We believe that the stage is now set for human clinical trials of putative cataract inhibitors. We present rough quantitative estimates of the trial parameters needed to assure an unambiguous determination of efficacy in a trial population. Such a trial simply requires a measurement of the time constant deltaT in the treated population relative to the untreated population. A successful outcome of the trial is indicated if deltaT increases by 20% over that found for the untreated population. Our estimates suggest efficacy could be determined in a two year trial involving about 300 subjects in the treated group.

AlphaB-crystallin selectively targets intermediate filament proteins during thermal stress

PURPOSE

AlphaB-Crystallin is a small heat shock protein (sHsp) expressed at high levels in the lens of the eye, where its molecular chaperone functions may protect against cataract formation in vivo. The purpose of this study was to identify protein targets for the sHsp alphaB-crystallin in lens cell homogenates during conditions of mild thermal stress.

METHODS

The authors report the use of a fusion protein, maltose-binding protein alphaB-crystallin (MBP-alphaB), immobilized on amylose resin as a novel method for isolating endogenous alphaB-crystallin-binding proteins from lens cell homogenates after mild thermal stress.

RESULTS

Sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and western immunoblot analyses showed selective interactions in lens cell homogenates between MBP-alphaB and endogenous alphaA- and alphaB-crystallins, the lens-specific intermediate filament proteins phakinin (CP49) and filensin (CP115), and vimentin during a mild 20-minute heat shock at 45 degrees C. No interactions were observed with the beta- or gamma-crystallins, or the cytoskeletal proteins actin, alpha-tubulin, and spectrin, although these proteins were present in lens cell homogenates. In contrast, gamma-crystallin and actin interacted with MBP-alphaB at 45 degrees C only in their purified states. The results obtained with MBP-alphaB were confirmed by immunoprecipitation reactions in which immunoprecipitation of native bovine alphaB-crystallin from heat-shocked lens cell homogenates resulted in the coprecipitation of phakinin and filensin.

CONCLUSIONS

In the lens the sHsp alphaB-crystallin may selectively target intermediate filaments for protection against unfolding during conditions of stress.

Disruption of the Sparc locus in mice alters the differentiation of lenticular epithelial cells and leads to cataract formation

SPARC (secreted protein acidic and rich in cysteine) is a matricellular protein that regulates cellular adhesion and proliferation. In this report, we show that SPARC protein is restricted to epithelial cells of the murine lens and ends abruptly at the equatorial bow region where lens fiber differentiation begins. SPARC protein was not detected in the lens capsule or in differentiated lens fibers. SPARC-null mice developed cataracts at approximately 3-4 months after birth, at which time posterior subcapsular opacities were observed by slit lamp ophthalmoscopy. Histological analyses of ocular sections from 3-month old animals revealed several microscopic abnormalities present in the SPARC-null mice but absent from the wild-type animals. Fiber cell elongation was incomplete posteriorly and resulted in displacement of the lenticular nucleus to the posterior of the lens. Nuclear debris was present in the posterior subcapsular region of the lens, an indication of the abnormal migration and elongation of either fetal or anterior epithelial cells, and the bow region was disrupted and vacuolated. In the anterior lens, the capsule appeared to be thickened and was lined by atypical, plump cuboidal epithelium. Moreover, anterior cortical fibers were swollen. Polyacrylamide gel electrophoresis of the epithelial, cortical and nuclear fractions of wild-type and SPARC-null lenses indicated no significant differences among the alpha-, beta-, and gamma-crystallins. Expression of alphaB-crystallin appeared similar in fiber cells of wild-type and SPARC-null lenses, although the distribution of alphaB-crystallin was asymmetric in SPARC-null lenses as a result of abnormal lens fiber differentiation. No evidence of atypical extracellular matrix deposition in areas other than the capsule was detected in wild-type or SPARC-null lens at 3 months of age. We conclude that the disruption of the Sparc locus in mice results in the alteration of two fundamental processes of lens development: differentiation of epithelial cells and maturation of fiber cells.

SPARC deficiency leads to early-onset cataractogenesis

PURPOSE

To determine the role of SPARC (secreted protein, acidic, and rich in cysteine) in cataractogenesis by examining mice deficient in a matricellular protein SPARC.

METHODS

Mice were rendered SPARC-deficient by a targeted disruption of the gene. Slit-lamp microscopy and histology were used to examine the eyes of SPARC-null and wild-type mice from birth to 14 months of age.

RESULTS

SPARC-null mice developed opacities in the posterior cortex of the eye as early as 1.5 months after birth. The diffuse cataracts appeared to progress toward the anterior cortex and reached maturity in many animals by 3.5 months of age. Early stages of cataractogenesis in SPARC-null mice included inhibition of normal lens fiber cell differentiation, degeneration of fiber cells, vacuole formation at the equator, and liquefaction of the cortex. No cataracts were detected in wild-type mice up to the age of 8 months.

CONCLUSIONS

The early onset of cataracts in SPARC-null mice establishes that the gene is essential to the maintenance of lens transparency.

A novel assay of angiogenesis in the quail chorioallantoic membrane: stimulation by bFGF and inhibition by angiostatin according to fractal dimension and grid intersection

In a novel assay of angiogenesis in the quail chorioallantoic membrane (CAM), we measured vascular pattern and angiogenic rate after homogeneous exposure of the entire vascular tree to recognized modulators of vessel growth. In comparison to phosphate-buffered saline (PBS)-treated controls, the vascular stimulator, basic fibroblast growth factor (bFGF or FGF-2), increased the rate of angiogenesis by a maximum of 72%, whereas a recently discovered angiogenic inhibitor, angiostatin, decreased the rate of vascular growth by a maximum of 68%. The perturbants were applied in PBS to the CAM of 7-day-old embryos (E7) cultured in petri dishes, and the embryos were cultured further until fixation at E8 or E9. For morphometry of the quasi-two-dimensional CAM vasculature, digital images of arterial endpoints from the middle region of the CAM were acquired in grayscale at a magnification of 10x, binarized to black/white, and skeletonized. The pattern of vessel branching was assessed by measurement of the fractal dimension (Df), and vessel density (rhov), with the method of grid intersection. Correlations between these two statistical techniques were linear (r2 ranged from 0.967 to 0.985). For skeletonized images at E9, Df and rhov of bFGF-treated samples were 1.55 +/- 0.01 and 782 +/- 26/cm2, respectively (relative to 1.49 +/- 0.02 and 583 +/- 60/cm2 for controls), and of angiostatin-treated samples, 1.43 +/- 0.02 and 424 +/- 74/cm2 (relative to 1.50 +/- 0.02 and 616 +/- 59/cm2 for controls). To establish normalization values for rates of angiogenesis, we analyzed untreated CAMs of E6 to E12. From E7 to E10 in skeletonized images, Df increased linearly from 1.37 +/- 0.01 to 1.54 +/- 0.01 and rhov from 311 +/- 67 to 746 +/- 124/cm2 (in both cases, r2 = 1.000). Thus, the rates of normal angiogenic growth as measured by Df and rhov were 0.06/day and 138/cm2-day, respectively. From E10 to E12, Df and rhov declined slightly. Differences between the vasculature of untreated and PBS-treated CAMs were statistically insignificant. In conclusion, vascular branching pattern and density in the quail CAM were stimulated by bFGF and inhibited by angiostatin. We quantified these changes with statistical significance by Df and rhov, which are expressed relative to the rates of normal developmental angiogenesis measured for the two parameters in untreated quail embryos.

ATP-enhanced molecular chaperone functions of the small heat shock protein human alphaB crystallin

We report direct experimental evidence that human alphaB-crystallin, a member of the small heat shock protein family, actively participates in the refolding of citrate synthase (CS) in vitro. In the presence of 3.5 mM ATP, CS reactivation by alphaB-crystallin was enhanced approximately twofold. Similarly, 3.5 mM ATP enhanced the chaperone activity of alphaB-crystallin on the unfolding and aggregation of CS at 45 degrees C. Consistent with these findings, cell viability at 50 degrees C was improved nearly five orders of magnitude in Escherichia coli expressing alphaB-crystallin. SDS/PAGE analysis of cell lysates suggested that alphaB-crystallin protects cells against physiological stress in vivo by maintaining cytosolic proteins in their native and functional conformations. This report confirms the action of alphaB-crystallin as a molecular chaperone both in vitro and in vivo and describes the enhancement of alphaB-crystallin chaperone functions by ATP.

Induction of multiple anti-c-erbB-2 specificities accompanies a classical idiotypic cascade following 2B1 bispecific monoclonal antibody treatment

The bispecific monoclonal antibody (bsmAb) 2B1, targeting the extracellular domain of c-erbB-2, the protein product of the HER-2/neu proto-ocogene, and Fc gamma RIII (CD16), expressed by human natural killer cells, neutrophils and differentiated monocytes, mediates the specific cytotoxic activity of these effector cells to tumor cells. A group of 24 patients with c-erbB-2-overexpressing tumors were treated with intravenously administered 2B1 in a phase I clinical trial and followed after treatment to evaluate the diversity and extent of the 2B1-induced humoral immune responses. As expected, 17 of 24 patients developed human anti-(murine Ig) antibodies (HAMA) to whole 2B1 IgG in a range from 100 ng/ml to more than 50000 ng/ml; 10 of these patients (42%) had strong (at least 1000 ng/ml) HAMA responses, some of which were still detectable at day 191. These responses were usually associated with similar reactivity to the F(ab')2 fragments of the parental antibodies 520C9 (anti-c-erbB-2) and 3G8 (anti-CD16). We sought evidence of an idiotypic cascade induction, indicating a prolonged specific treatment-induced effect on at least one selected target of 2B1. Using competition-based enzyme-linked immunosorbent assays, specific anti-idiotypic antibodies (Ab2) were detectable against 520C9 in 11 patients and against 3G8 in 13 patients. Peak anti-idiotypic antibodies generally occurred 3-5 weeks from treatment initiation, with a downward trend thereafter. There was a statistically significant correlation among the induction of significant HAMA responses, anti-idiotypic antibody production and the development of antibodies to c-erbB-2. The anti-c-erbB-2 responses, which were distinct from anti-anti-idiotypic (Ab3) antibodies, were detected in the post-treatment sera of 6/16 patients examined. No obvious correlation could be made between the development of humoral immune responses, the dose received, and the clinical response. Future investigation involving 2B1 therapy will concentrate on investigating an association of these humoral responses to any c-erbB-2-specific cellular responses. Manipulations of 2B1 therapy effects that augment immunity to c-erbB-2 could provide additional avenues for immunotherapy with this and other bispecific antibodies.

Protein changes during aging and the effects of long-term cortisol treatment in macaque monkey lens

Macaca nemestrina pig-tail macaques were administered daily oral doses of 3.85 or 5.78 mg/kg of cortisol for 1 year. The ages of the macaques were from 19 to 29 years. After 1 year, lenses were observed using a slitlamp ophthalmoscope and the stage of cataract was classified in each eye. Enucleated lenses were analyzed for content of soluble and insoluble proteins. Lens proteins were analyzed using SDS polyacrylamide gel electrophoresis (SDS-PAGE) and the changes in lens proteins were quantified using densitometry of the individual gels. Untreated control lenses were obtained over the range of 4 to 29 years of age and the proteins were analyzed. A slow progressive increase in the cataract stage and in the proportion of insoluble protein aggregates corresponded with the animal age, not the cortisol treatment. The observed changes in the protein components may suggest an important role for cytoskeletal proteins in lens transparency during aging. Exposure to high doses of oral steroids over a period of 1 year did not result in detectable modification of crystallin or cytoskeletal proteins. Even at high doses, longer exposure may be necessary to produce the cataract associated with steroid administration.

Quasielastic light scattering study of the living human lens as a function of age

PURPOSE

To determine contributions of molecular scattering elements to the increase with age in the light scattered from the human ocular lens in vivo.

METHODS

We used quasielastic light scattering to measure autocorrelation functions of the intensity of light scattered in vivo from three locations (anterior, nuclear and posterior) along the optic axis in ocular lenses of 225 subjects, ranging from 17 to 63 years of age. We deduced probability distributions of key parameters (Is, If, Ii, IT), which describe contributions of slowly diffusing (Is), rapidly diffusing (If) and relatively immobile (Ii) scattering elements to the total light intensity (IT) scattered into the collection optics. We deduced characteristic time tau s and tau f that describe the Brownian motion of scattering elements.

RESULTS

Probability distributions for each age decile show clearly defined shifts in key parameters with age. IT at the nucleus increases by a factor of three from age 20 to 60 years. This increase is produced principally by an approximate five-fold increase is Is. IT and Is and can be detected with an accuracy of approximately +/- 10%. We estimate threshold values for IT, which mark the boundary beyond which clinical cataract becomes manifest. This boundary represents 6 to 8 times the light scattering efficiency expected from the newborn lens.

CONCLUSIONS

This methodology permits a sensitive, quantitative, clinically useful representation of the pre-cataractous molecular changes associated with aging in the living human lens.

Loss of cytoskeletal proteins and lens cell opacification in the selenite cataract model

This study of lens protein composition found that some cytoskeletal proteins were degraded during the earliest stages of cataract formation. Cataract was induced in 13-14 day old rats by a single subcutaneous injection of sodium selenite (19 mumol kg-1). By 24 hr after the injection of selenite, the ratio of insoluble to soluble protein increased as lens opacification began. The increase in insoluble protein aggregates was correlated with an accelerated loss of proteins having molecular weights of 42, 55/57 and 235 kDa which reacted with antibodies to the cytoskeletal proteins actin, tubulin/vimentin and spectrin, respectively. We observed the loss of 49, 60 and 90 kDa proteins which were not identified. In the lenses of animals protected from protein aggregation and opacification by administration of 1.5 mmol kg-1 pantethine, the pattern of proteins in SDS-PAGE gels resembled the pattern for proteins from transparent lenses of normal untreated animals and loss of cytoskeletal proteins was prevented.

Human alphaB-crystallin. Small heat shock protein and molecular chaperone

The polymerase chain reaction was used to amplify a cDNA sequence encoding the human alphaB-crystallin. The amplified cDNA fragment was cloned into the bacterial expression vector pMAL-c2 and expressed as a soluble fusion protein coupled to maltose-binding protein (MBP). After maltose affinity chromatography and cleavage from MBP by Factor Xa, the recombinant human alphaB-crystallin was separated from MBP and Factor Xa by anion exchange chromatography. Recombinant alphaB-crystallin was characterized by SDS-polyacrylamide electrophoresis (PAGE), Western immunoblot analysis, Edman degradation, circular dichroism spectroscopy, and size exclusion chromatography. The purified crystallin migrated on SDS-PAGE to an apparent molecular weight (Mr approximately 22,000) that corresponded to total native human alpha-crystallin and was recognized on Western immunoblots by antiserum raised against human alphaB-crystallin purified from lens homogenates. Chemical sequencing, circular dichroism spectroscopy, and size exclusion chromatography demonstrated that the recombinant crystallin had properties similar or identical to its native counterpart. Both recombinant alphaB-crystallin and MBP-alphaB fusion protein associated to form high molecular weight complexes that displayed chaperone-like function by inhibiting the aggregation of alcohol dehydrogenase at 37 degrees C and demonstrated the importance of the C-terminal domain of alphaB-crystallin for chaperone-like activity.