Widespread skeletal metastatic potential of human lung cancer revealed by green fluorescent protein expression

To understand the skeletal metastatic pattern of non-small cell lung cancer, we developed a stable high-expression green fluorescent protein (GFP) transductant of human lung cancer cell line H460 (H460-GFP). The GFP-expressing lung cancer was visualized to metastasize widely throughout the skeleton when implanted orthotopically in nude mice. H460 was transduced with the pLEIN retroviral expression vector containing the enhanced GFP and the neomycin (G418) resistance gene. A stable high GFP-expressing clone was selected in vitro using 800 microg/ml G418. Stable high-level expression of GFP was maintained in s.c.-growing tumors formed after injecting H460-GFP cells in nude mice. To use H460-GFP for visualization of metastasis, fragments of s.c.-growing H460-GFP tumors were implanted by surgical orthotopic implantation in the left lung of nude mice. Subsequent micrometastases were visualized by GFP fluorescence in the contralateral lung, plural membrane, and widely throughout the skeletal system including the skull, vertebra, femur, tibia, pelvis, and bone marrow of the femur and tibia. The use of GFP-expressing H460 cells transplanted by surgical orthotopic implantation revealed the extensive metastatic potential of lung cancer in particular to widely disseminated sites throughout the skeleton. This new metastatic model can play a critical role in the study of the mechanism of skeletal and other metastasis in lung cancer and in screening of therapeutics that prevent or reverse this process.

Anticancer efficacy in vivo and in vitro, synergy with 5-fluorouracil, and safety of recombinant methioninase

The elevated exogenous-methionine dependency of tumors for growth has been observed in all major cancer cell types. We have previously cloned a methioninase (rMETase) from Pseudomonas putida to deplete methionine. Growth inhibition followed by apoptotic cell death was induced by treatment of tumor cells with rMETase in vitro. A single i.p. injection of 300 units of rMETase can lower the serum methionine level in the mice from 70 microM to less than 1 microM within 2 h and maintain this depleted level for 8 h. Repeated dosing of rMETase of tumor-bearing mice could be administered without acute immune-hypersensitivity. rMETase treatment demonstrated growth inhibitory activity against human tumors in nude mice, including those which were multiple drug-resistant. No body weight loss or hematotoxicity, except a slight anemia, was found throughout the therapy. The combined treatment of the Lewis lung carcinoma with a fixed rMETase dose and increasing doses of 5-fluorouracil (5-FU) resulted in a dose-dependent enhanced antitumor efficacy for survival as well as tumor growth inhibition. Thus, methionine depletion by rMETase potentiates the antitumor efficacy of 5-FU. The data presented in this report thus indicate that rMETase is active alone, is synergistic in combination with 5-FU, and has negligible toxicity suggesting a novel clinical approach for effective cancer therapy.

Topical liposome targeting of dyes, melanins, genes, and proteins selectively to hair follicles

For therapeutic and cosmetic modification of hair, we have developed a hair-follicle-selective macromolecule and small molecule targeting system with topical application of phosphatidylcholine-based liposomes. Liposome-entrapped melanins, proteins, genes, and small-molecules have been selectively targeted to the hair follicle and hair shafts of mice. Liposomal delivery of these molecules is time dependent. Negligible amounts of delivered molecules enter the dermis, epidermis, or bloodstream thereby demonstrating selective follicle delivery. Naked molecules are trapped in the stratum corneum and are unable to enter the follicle. The potential of the hair-follicle liposome delivery system for therapeutic use for hair disease as well as for cosmesis has been demonstrated in 3-dimensional histoculture of hair-growing skin and mouse in vivo models. Topical liposome selective delivery to hair follicles has demonstrated the ability to color hair with melanin, the delivery of the active lac-Z gene to hair matrix cells and delivery of proteins as well. Liposome-targeting of molecules to hair follicles has also been achieved in human scalp in histoculture. Liposomes thus have high potential in selective hair follicle targeting of large and small molecules, including genes, opening the field of gene therapy and other molecular therapy of the hair process to restore hair growth, physiologically restore or alter hair pigment, and to prevent or accelerate hair loss.

Electroporation enhances therapeutic efficacy of anticancer drugs: treatment of human pancreatic tumor in animal model

BACKGROUND

A new method of cancer treatment called electroporation therapy (EPT) which uses pulsed electric fields in combination with a chemotherapeutic agent is being developed to treat human pancreatic tumors. Such a combination has been found to increase the cytotoxic effect of the drug to tumor cells.

METHODS

Human pancreatic tumors (Pan-4-JCK) were implanted subcutaneously onto nude mice. The animals were treated with EPT using bleomycin, mitomycin C or carboplatin as a single agent, and their effect on tumor growth was monitored over a period of 89 days.

RESULTS

The tumors treated with either the drug or pulse alone showed increased tumor growth. However, tumors treated with EPT using any one of the three drugs showed significant to complete regression of tumors. Among the three drugs used, the order of efficacy was: bleomycin >> mitomycin C > carboplatin.

CONCLUSIONS

These results are sufficient to warrant limited clinical trials of EPT for pancreatic cancers.

Electroporation therapy of human larynx tumors HEp-2 implanted in nude mice

BACKGROUND

Electroporation therapy (EPT) uses reversible membrane permeabilization of cells by electrical pulses for intracellular delivery of poorly permeating drugs like bleomycin. This treatment modality has been found to significantly increase the cytotoxic effect of the drug to tumor cells.

METHODS

Tumors of human epidermoid carcinoma of larynx (HEp-2) were xenografted subcutaneously in nude mice. EPT consisted of intratumoral injection of belomycin followed by 6 x 100 microseconds square wave electrical pulses of 1130 Volts. The effect of treatment on tumor growth was monitored over a period of 67 days.

RESULTS

Complete regression of the tumors was observed in 83% of the treated mice 67 days after treatment. These findings were confirmed by histopathological analysis of tumor samples from the treated sites, which showed complete absence of tumor cells.

CONCLUSIONS

The results indicate that electroporation therapy is very effective and has potential for treating laryngeal tumors clinically.

Surgical orthotopic implantation allows high lung and lymph node metastatic expression of human prostate carcinoma cell line PC-3 in nude mice

BACKGROUND

Prostate cancer is the second leading cause of male death in the United States. When diagnosed, nearly half the cases have metastatic lesions. An animal model of human prostate cancer demonstrating spontaneous metastasis from the orthotopic site after tumor implantation should be of great help for us to understand the disease and to formulate treatment strategy. We report here a high metastatic model of human prostate cancer PC-3.

METHODS

We developed microsurgical techniques, termed surgical orthotopic implantation (SOI), to implant histologically intact tumor tissues orthotopically in immunodeficient mice. In this study intact tissue of the human prostate cancer cell line PC-3, harvested from a subcutaneous tumor in a nude mouse, was implanted to the ventral lateral lobes of the prostate gland in a series of nude mice. Mice were sacrificed when found moribund, and autopsy and histology were performed subsequently.

RESULTS

A high frequency of lymph node and lung metastasis was noted upon histological examination. The extensive and widespread lung metastasis following orthotopic implantation of PC-3 is, to the best of our knowledge, the first report in the literature.

CONCLUSIONS

In contrast to orthotopic injection of cell suspensions, no multiple metastatic cell selection was necessary after SOI for significant expression of the metastatic potential of PC-3. We conclude that the stromal tissue architecture maintained in the implanted tumor played a critical role in tumor growth and progression.

Genistein inhibits the growth of human-patient BPH and prostate cancer in histoculture

BACKGROUND

There is strong epidemiological evidence that prostate disease is significantly less prevalent in the Orient, where the intake of soy products is very high, than in the United States. We therefore undertook a study of the effects of genistein, a major component of soy, on growth of human-patient benign prostatic hypertrophy (BPH) and prostate cancer tissue in three-dimensional collagen gel-supported histoculture.

METHODS

Surgical specimens of human BPH and cancer were histocultured for 5 days to study the effects of genistein on growth, as measured by inhibition of 3H-thymidine incorporation per microgram protein on day 5.

RESULTS

Genistein in doses of 1.25-10 micrograms/ml decreased the growth of BPH tissue in histoculture in a dose-dependent manner, with little additional effect at higher doses. Prostate cancer tissue in histoculture was similarly inhibited by these doses of genistein.

CONCLUSIONS

Genistein decreases the growth of both BPH and prostate cancer tissue in histoculture. The data suggest that genistein has potential as a therapeutic agent for BPH and prostate cancer.

Polyethylene glycol conjugation of recombinant methioninase for cancer therapy

Recombinant methioninase (rMETase) is a homotetrameric pyridoxal 5'-phosphate enzyme of 172-kda molecular mass derived from Pseudomonas putida and cloned in Escherichia coli. rMETase has been found previously to be an effective, anti-tumor agent in vitro and in vivo. The enzyme targets the elevated minimal methionine requirement seen in all tumor types. In order to prevent immunological reactions which might be produced by multiple dosing of rMETase and to prolong the serum half-life of rMETase, the N-hydroxysuccinimidyl ester of methoxypolyethylene glycol propionic acid (M-SPA-PEG 5000) has been coupled to rMETase. Molar ratios of M-SPA-PEG-5000 (PEG) to rMETase from 10 to 40 were used for PEGylation of rMETase. PEGylation reactions were run at 20 degrees C for 30 to 60 min in reaction buffer (20 mM sodium phosphate buffer, pH 8.3). The PEGylated molecules (PEG-rMETase) were purified from unreacted PEG with Amicon 30 K centriprep concentrators or by Sephacryl S-300 HR gel-filtration chromatography. Unreacted rMETase was removed by DEAE Sepharose FF anion-exchange chromatography. The resulting PEG-rMETase subunit, from a PEG/rMETase ratio of 30/1 in the synthetic reaction, had a molecular mass of approximately 53 kda determined by matrix-assisted laser desorption/ionization mass spectrometry, indicating the conjugation of two PEG molecules per subunit of rMETase and eight per tetramer. PEG-rMETase molecules obtained from reacting ratios of PEG /rMETase of 30/1 had enzyme activities of 70% of unmodified rMETase. PEGylation of rMETase increased the serum half-life of the enzyme in rats to approximately 160 min compared to 80 min for unmodified rMETase. PEG-rMETase could deplete serum methionine levels to less than 0.1 microM for approximately 8 h compared to 2 h for rMETase in rats. Efficacy studies of PEG-rMETase on human lung cancer and kidney cancer cells in vitro demonstrated a 50% inhibitory concentration (IC50) of 0.04 and 0.06 units/ml, respectively. These IC50 values were almost identical to unmodified rMETase, thus indicating maintenance of antitumor efficacy in the PEGylated enzyme. PEG-rMETase had an IC50 for normal lung and kidney cells of 0.8 and 1.5 units/ml, respectively, similar to rMETase. The efficacy data indicated that PEG-rMETase maintained the high level tumor selectivity of rMETase. PEG-rMETase injected intravenously in mice demonstrated a tumor/blood retention ratio of approximately 1/6 compared to 1/10 of unmodified enzyme, indicating that PEG-rMETase distributes to the tumor at least as effectively as rMETase.

Prostate-specific antigen testing practices and outcomes

OBJECTIVES

To characterize prostate-specific antigen (PSA) testing practices in a hospital-based primary care clinic, and to determine the outcomes of PSA testing, including urology referrals, biopsies, cancers detected, and cancer treatments.

DESIGN

Retrospective cohort study. Data were obtained from computerized Department of Veterans Affairs (VA) files and the statewide New Mexico Surveillance, Epidemiology, and End Results (SEER) tumor registry.

SETTING

Primary care clinics in a university-affiliated VA Medical Center.

PATIENTS

Subjects were 1,448 men without cancer undergoing PSA testing in 1993 with follow-up through 1994.

MAIN RESULTS

Twenty-one percent of clinic enrollees at least 40 years of age were tested with PSA, including 58 who were 75 years of age or older. By the end of 1994, 40.0% (95% confidence interval [CI] 37.2%, 42.8%) were retested; 25.6% (95% CI 21.7%, 29.5%) of initial retesting occurred within 6 months. Overall, 20.7% (95% CI 18.9%, 22.5%) of PSA tests in the cohort were for men aged 75 years or older and were repeated within 6 months. Among the 193 subjects with PSA values > or = 4.0 ng/mL, 86.0% (95% CI 81.1%, 90.9%) were followed-up in urology clinic, and 46.1% (95% CI 39.1%, 53.1%) underwent biopsy. Only 11 of 51 men aged 75 years or older who were referred to urologists for an elevated PSA underwent biopsy. Forty cancers were diagnosed-a detection rate of 2.8% (95% CI 2.0%, 3.6%). Of these, 28 were organ-confined, 7 had regional invasion, and 3 had distant metastases.

CONCLUSIONS

Primary care providers frequently ordered PSA tests, but a substantial proportion of testing occurred outside recommended age ranges and screening intervals. Older patients with elevated PSA values often did not complete diagnostic workups. Better adherence to screening guidelines may limit the number of both PSA tests and urology referrals.

Methionine-depletion modulates the efficacy of 5-fluorouracil in human gastric cancer in nude mice

Human tumors are generally methionine (MET)-dependent in that their growth is inhibited by MET-depletion down to levels that will still allow normal cell growth. The differential effect of methionine depletion on tumor and normal cells has suggested that methionine depletion may be able to modulate many and possibly all classes of cancer drugs. In this report, we determined if MET-depletion could modulate 5-fluorouracil (5-FU) efficacy on the human gastric cancer xenograft, SC-1-NU in nude mice. The tumor-bearing mice were treated with a MET-free diet and intraperitoneal administration of 5-FU at a dose of 30 mg/kg given for four cycles. MET depletion enhanced the antitumor activity of 5-FU by approximately two-fold with statistical significance of p < 0.05. The MET-free diet increased intratumoral thymidylate synthetase inhibition early after 5-FU administration; Therefore, MET-depletion was thought to increase the 5-FU antitumor activity by modulating intratumoral folate metabolism. The data in this report suggest the high clinical potential of methionine depletion, combined with 5-FU and leucovorin on refractory tumors such as stomach cancer.

Governing step of metastasis visualized in vitro

Metastasis is the ultimate life-threatening stage of cancer. The lack of accurate model systems thwarted studies of the metastatic cell's basic biology. To follow continuously the succeeding stages of metastatic colony growth, we heritably labeled cells from the human lung adenocarcinoma cell line ANIP 973 with green fluorescent protein (GFP) by transfection with GFP cDNA. Labeled cells were then injected intravenously into nude mice, where, by 7 days, they formed brilliantly fluorescing metastatic colonies on mouse lung [Chishima, T., Miyagi, Y., Wang, X., Yang, M., Tan, Y., Shimada, H., Moossa, A. R. & Hoffman, R. M. (1997) Clin. Exp. Metastasis 15, 547-552]. The seeded lung tissue was then excised and incubated in the three-dimensional sponge-gel-matrix-supported histoculture that maintained the critical features of progressive in vivo tumor colonization while allowing continuous access for measurement and manipulation. Tumor progression was continuously visualized by GFP fluorescence in the same individual cultures over a 52-day period, during which the tumors spread throughout the lung. Histoculture tumor colonization was selective for lung cancer cells to grow on lung tissue, because no growth occurred on histocultured mouse liver tissue, which was also observed in vivo. The ability to support selective organ colonization in histoculture and visualize tumor progression by GFP fluorescence allows the in vitro study of the governing processes of metastasis [Kuo, T.-H., Kubota, T., Watanbe, M., Furukawa, T., Teramoto, T., Ishibiki, K., Kitajima, M., Moossa, A. R., Penman, S. & Hoffman, R. M. (1995) Proc. Natl. Acad. Sci. USA 92, 12085-12089]. The results presented here provide significant, new opportunities to understand and to develop treatments that prevent and possibly reverse metastasis.

Antimetastatic activity of the new platinum analog [Pt(cis-dach) (DPPE).2NO3] in a metastatic model of human bladder cancer

Surgical orthotopic implantation (SOI) of histologically intact human RT-4 bladder tumor tissue in nude mice resulted in local growth, invasion, regional extension and metastases as well as distant metastases to other organ sites and lymph nodes, thus mimicking the bladder cancer patient. This metastatic bladder tumor animal model was treated with two doses of new platinum analog ¿Pt(cis-dach)(DPPE).2NO3¿ for the evaluation of antimetastatic efficacy compared to two doses of cisplatinum. Unlike the untreated control group or the group treated with the low dose of cisplatinum, there were no metastases in either the high or low-dose platinum-analog-treated groups and the high-dose cisplatinum-treated group. The results obtained with this patient-like nude-mouse model of bladder cancer indicate that the new platinum analog appears to be a valuable lead compound with antimetastatic efficacy and clinical potential.

Metastatic patterns of lung cancer visualized live and in process by green fluorescence protein expression

We demonstrate here the visualization of human lung cancer metastasis live and in process in nude mice by green fluorescent protein (GFP) expression. The human lung adenocarcinoma cell line Anip 973 stably transfected with the humanized GFP-S65T cDNA was selected for very bright green fluorescence. GFP-transfected lung cancer cells were initially inoculated subcutaneously in nude mice. Five weeks after transplantation, the resulting tumor had reached over 1 cm in diameter and had very bright GFP fluorescence. Fragments of subcutaneous tumor were implanted onto the visceral pleura of the left lung of nude mice by surgical orthotopic implantation (SOI) of histologically-intact tissue via transverse thoracotomy. The ipsilateral resulting tumor was highly fluorescent due to GFP expression. GFP expression allowed the visualization of the advancing margin of the ipsilateral tumor into the fresh normal lung tissue. Lymphogenous and direct-seeding metastases in the pulmonary hilum, cervical lymph nodes, the mediastinum and contralateral pleural cavity and contralateral lung in the SOI-treated mice were brightly visualized by GFP expression in fresh tissue. GFP-transfected and untransfected tumor had similar metastatic characteristics suggesting that GFP expression had no effect on metastasis itself. The results with the GFP-transfected tumor cells, combined with the use of SOI, demonstrate a fundamental advance in the visualization and study of lung cancer metastasis in process.

Mitomycin C and cisplatin increase survival in a human pancreatic cancer metastatic model

Pancreatic cancer is one of the most intractable of all human cancers. We have previously developed a patient-like model of human pancreatic cancer by surgical orthotopic implantation (SOI). After SOI of the human tumor xenograft PAN-12-JCK into the tail of the nude mouse pancreas, mitomycin C (MMC) and cisplatin (DDP) were administered intraperitoneally at a dose of 4 and 6 mg/kg, respectively, on day-7. The mice were observed for 95 days. There was a statistically significant increase in disease-free and overall survival rates in the MMC- and MMC + DDP-treated groups. Local tumor growth was eliminated only in the group treated with MMC + DDP. Hepatic metastasis and peritoneal disseminations were completely inhibited by MMC but not DDP. This study demonstrates the usefulness of the SOI model of pancreatic cancer to study the differential efficacy of agents affecting primary tumor growth metastasis and survival, thus presenting an opportunity for the discovery of new agents for this highly resistant cancer.

Recombinant methioninase infusion reduces the biochemical endpoint of serum methionine with minimal toxicity in high-stage cancer patients

The tumor-specific increased minimal requirement for methionine has been shown to be a highly promising therapeutic target. To attack this target we have previously cloned the methioninase gene from Pseudomonas putida and produced recombinant methioninase (rMETase). A pilot Phase I clinical trial has been carried out to determine rMETase toxicity, rMETase pharmacokinetics, and serum MET-depletion in cancer patients. Patients with advanced breast cancer, lung cancer, renal cancer and lymphoma were given a single rMETase treatment at doses ranging from 5,000 to 20,000 units by i.v. infusion over 6-24 hours. No clinical toxicity was observed in any patient after rMETase treatment. rMETase levels reached 0.1 to 0.4 units per ml of serum in the patients which correspond to therapeutic levels in vitro. The lowest serum methionine levels in rMETase-treated patients were 0.1% of the pre-treatment levels corresponding to approximately 0.1 microM, which also correlates to therapeutic levels in vitro. The results of the rMETase pilot Phase I clinical trial therefore indicate that i.v. infusion of rMETase is safe and effectively depletes its biochemical target of serum methionine suggesting potential efficacy in future clinical trials.

Visualization of the metastatic process by green fluorescent protein expression

We demonstrate here the visualization of the cancer metastatic process in live tissue in vivo by green fluorescent protein (GFP) expression. The human lung adenocarcinoma cell-line Anip 973 was transfected with the humanized GFP-S65T cDNA and stable high-level GFP-expressing transfectants were established. GFP transfectants were initially inoculated subcutaneously in nude mice. Five weeks after transplantation, when the tumor had reached 1.2 cm in diameter, fragments of subcutaneously tumor were implanted onto the visceral pleura of nude mice by surgical orthtopic implantation (SOI) as a spontenous metastatic model. GFP expressing cells were injected intravenously in nude mice as an experimental hematogenous metastasis model. Mice were sacrificed four and eight weeks after treatment. At eight weeks, SOI-treated mice had lymphogenous (3/4 mice) and direct seeding (3/4) metastasis in the pulmonary hilum, cervical lymph nodes, the mediastinum and contralateral pleural cavity as detected by GFP expression in live tissue. All intravenously injected mice had metastases in the lung (4/4) and some of them had metastases in the brain (2/4) and other organs (1/4) as detected by GFP expression in fresh tissue. Some of the lung metastases produced by intravenous injection remained as dormant small colonies even eight weeks after treatment. These different metastatic patterns after SOI and intravenous injection visualized by GFP expression indicates that initial steps of the metastatic cascade influence the subsequent progression of metastasis.

Cancer invasion and micrometastasis visualized in live tissue by green fluorescent protein expression

We report the establishment of stable, high-level green fluorescent protein (GFP)-expressing cell lines in vitro that permit the detection and visualization of distant micrometastases when they are implanted orthotopically in nude mice. Chinese hamster ovary cells were transfected with the dicistronic expression vector containing the humanized GFP cDNA. A stable GFP-expressing clone was selected in 1.5 microM methotrexate in vitro and injected s.c. in nude mice. Stable high-level expression of GFP was maintained in the s.c. growing tumors. To use GFP expression for metastasis studies, fragments of s.c. growing tumor, which are comprised of GFP-expressing cells, were implanted by surgical orthotopic implantation in the ovary of nude mice. Subsequent micrometastases were detected in systemic organs and could be visualized by GFP fluorescence in the lung, liver, and other organs down to the single-cell level. With this fluorescent tool, we detected and visualized for the first time tumor cells at the microscopic level in fresh viable tissue in their normal host organ. Confocal microscopy further enabled us to study physiologically relevant patterns of invasion and micrometastasis.

5-FU-induced apoptosis correlates with efficacy against human gastric and colon cancer xenografts in nude mice

Apoptosis may be an important mechanism by which cancer cells are killed by certain agents. It is reported here that apoptosis is a key event in the killing of human tumor cells by 5-fluorouracil (5-FU) in vivo. Apoptosis induced by 5-FU was determined using two human gastrointestinal tumor xenografts serially transplanted into nude mice: a gastric carcinoma (SC-1-NU) highly sensitive to 5-FU and a colon carcinoma (Co-4) less sensitive to 5-FU. Apoptosis was assayed using the terminal deoxynucleotidyl transferase (TdT)-mediated deoxyuridine triphosphate (dUTP)-biotin nick end labeling method in paraffin-embedded tissue sections, and by flow-cytometric analysis. Apoptosis-positive cells increased gradually during treatment. 24 hours after the initiation of 5-FU treatment a maximum, of 15.4% of the Co-4 cells were apoptotic. 48 hours after the initiation of 5-FU treatment, apoptosis was found in 34% of the tumor cells in the SC-1-NU strain. Flow-cytometry demonstrated the increase of S-phase fractions in both strains after the administration of 5-FU, and this coincided with the appearance of apoptotic-positive cells. Although the intrinsic. TS activities of two strains differed, TS activities were markedly suppressed in both strains immediately after the administration of 5-FU. Concentration of 5-FU in RNA (F-RNA) increased gradually in both strains, reaching a maximum 24 hours after the administration of 5-FU. These results suggest that apoptosis and inhibition of DNA synthesis induced by 5-FU are closely associated with its antitumor effect.

Interstitial lung disease in an adult with Fanconi anemia: clues to the pathogenesis

We have studied a 38-year-old man with a prior diagnosis of Holt-Oram syndrome, who presented with diabetes mellitus. He had recently taken prednisone for idiopathic interstitial lung disease and trimethoprim-sulfamethoxazole for sinusitis. Thrombocytopenia progressed to pancytopenia. The patient had skeletal, cardiac, renal, cutaneous, endocrine, hepatic, neurologic, and hematologic manifestations of Fanconi anemia (FA). Chest radiographs showed increased interstitial markings at age 25, dyspnea began in his late 20s, and he stopped smoking at age 32. At age 38, computerized tomography showed bilateral upper lobe fibrosis, lower lobe honeycombing, and bronchiectasis. Pulmonary function tests, compromised at age 29, showed a moderately severe obstructive and restrictive pattern by age 38. Serum alpha-1 antitrypsin level was 224 (normal 85-213) mg/dL and PI phenotype was M1. Karyotype was 46,XY with a marked increase in chromosome aberrations induced in vitro by diepoxybutane. The early onset and degree of pulmonary disease in this patient cannot be fully explained by environmental or known genetic causes. The International Fanconi Anemia Registry (IFAR) contains no example of a similar pulmonary presentation. Gene-environment (ecogenetic) interactions in FA seem evident in the final phenotype. The pathogenic mechanism of lung involvement in FA may relate to oxidative injury and cytokine anomalies.

Overexpression and large-scale production of recombinant L-methionine-alpha-deamino-gamma-mercaptomethane-lyase for novel anticancer therapy

The goal of the next generation of cancer chemotherapy is effective tumor-selectivity. A tumor-selective target with high therapeutic potential is the elevated methionine requirement of tumor cells relative to normal cells. We have termed the elevated requirement for methionine in tumors methionine dependence. To selectively target the methionine dependence of tumors for treatment on a large-scale preclinical and clinical basis, the L-methionine alpha-deamino-gamma-mercaptomethane-lyase (methioninase, METase) gene from Pseudomonas putida has been cloned in Escherichia coli using the polymerase chain reaction (PCR). The METase gene was then ligated into the pT7-7 overexpression plasmid containing the T7 RNA polymerase promoter and recloned in E. coli strain BL21(DE3). The pAC-1 clone was isolated by its yellow-orange color which is due to high enrichment of the pyridoxal phosphate-containing recombinant methioninase (rMETase) and distinguished rMETase-overproducer from rMETase-negative colonies. A scale-up production protocol which contained a heat step, two DEAE Sepharose FF ion-exchange, and one ActiClean Etox endotoxin-affinity chromatography columns has been established. The pAC-1 clone produces rMETase at approximately 10% of the total soluble protein and up to 1 g/liter in shake-flask culture. The protocol can produce therapeutic rMETase at the multi-gram level per batch with high yield (> 60%), high purity (> 98%), high stability, and low endotoxin. Purified rMETase is stable to lyophilization. The t1/2 of rMETase was 2 h when rMETase was administered by i.v. injection in mice. Studies of the antitumor efficacy of rMETase in vitro and in vivo on human tumors xenografted in nude mice demonstrated that all types of human tumors tested including those from lung, colon, kidney, brain, prostate, and melanoma were sensitive to rMETase. In contrast, normal cells were insensitive to rMETase in vitro and correspondingly, no toxicity was detected in vivo at the effective doses. In conclusion, the overexpression clone and large-scale production protocols for rMETase have enabled rMETase to be used as a tumor-selective therapeutic with broad indication and high promise for effective, low-toxicity human cancer therapy.