Search

Charles D Smith,1 Lynn W Maines,1 Staci N Keller,1 Vered Katz Ben-Yair,2 Reza Fathi,2 Terry F Plasse,2 Mark L Levitt2 1Apogee Biotechnology Corporation, Hummelstown, PA, USA; 2RedHill Biopharma LTD, Tel Aviv, IsraelCorrespondence: Charles D Smith, Apogee Biotechnology Corporation, 1214 Research Blvd, Suite 2015, Hummelstown, PA, 17036, USA, Tel +1 843 814 9257, Email CDSmith@apogee-biotech.comAbstract: The Covid-19 pandemic driven by the SARS-CoV-2 virus continues to exert extensive humanitarian and economic stress across the world. Although antivirals active against mild disease have been identified recently, new drugs to treat moderate and severe Covid-19 patients are needed. Sphingolipids regulate key pathologic processes, including viral proliferation and pathologic host inflammation. Opaganib (aka ABC294640) is a first-in-class clinical drug targeting sphingolipid metabolism for the treatment of cancer and inflammatory diseases. Recent work demonstrates that opaganib also has antiviral activity against several viruses including SARS-CoV-2. A recently completed multinational Phase 2/3 clinical trial of opaganib in patients hospitalized with Covid-19 demonstrated that opaganib can be safely administered to these patients, and more importantly, resulted in a 62% decrease in mortality in a large subpopulation of patients with moderately severe Covid-19. Furthermore, acceleration of the clearance of the virus was observed in opaganib-treated patients. Understanding the biochemical mechanism for the anti-SARS-CoV-2 activity of opaganib is essential for optimizing Covid-19 treatment protocols. Opaganib inhibits three key enzymes in sphingolipid metabolism: sphingosine kinase-2 (SK2); dihydroceramide desaturase (DES1); and glucosylceramide synthase (GCS). Herein, we describe a tripartite model by which opaganib suppresses infection and replication of SARS-CoV-2 by inhibiting SK2, DES1 and GCS. The potential impact of modulation of sphingolipid signaling on multi-organ dysfunction in Covid-19 patients is also discussed.Keywords: opaganib, ABC294640, sphingolipid, sphingosine kinase, dihydroceramide desaturase, glucosylceramide synthase

Once a patient has been diagnosed with severe COVID-19 pneumonia, treatment options have limited effectiveness. Opaganib is an oral treatment under investigation being evaluated for treatment of hospitalized patients with severe COVID-19 pneumonia. A randomized, placebo-controlled, double-blind phase 2/3 trial was conducted in 57 sites worldwide from August 2020 to July 2021. Patients received either opaganib (n = 230; 500 mg twice daily) or matching placebo (n = 233) for 14 days. The primary outcome was the proportion of patients no longer requiring supplemental oxygen by day 14. Secondary outcomes included changes in the World Health Organization Ordinal Scale for Clinical Improvement, viral clearance, intubation, and mortality at 28 and 42 days. Pre-specified primary and secondary outcome analyses did not demonstrate statistically significant benefit (except nominally for time to viral clearance). Post-hoc analysis revealed the fraction of inspired oxygen (FIO 2 ) at baseline was prognostic for opaganib treatment responsiveness and corresponded to disease severity markers. Patients with FIO 2 levels at or below the median value (≤60%) had better outcomes after opaganib treatment (n = 117) compared to placebo (n = 134). The proportion of patients with ≤60% FIO 2 at baseline that no longer required supplemental oxygen (≥24 h) by day 14 of opaganib treatment increased (76.9% vs. 63.4%; nominal p -value = 0.033). There was a 62.6% reduction in intubation/mechanical ventilation (6.84% vs. 17.91%; nominal p -value = 0.012) and a clinically meaningful 62% reduction in mortality (5.98% vs. 16.7%; nominal p -value = 0.019) by day 42. No new safety concerns were observed. While the primary analyses were not statistically significant, post-hoc analysis suggests opaganib benefit for patients with severe COVID-19 requiring supplemental oxygen with an FIO 2 of ≤60%. Further studies are warranted to prospectively confirm opaganib benefit in this subpopulation.

Upamostat is an orally available small-molecule serine protease inhibitor that is a highly potent inhibitor of trypsin 1, trypsin 2, trypsin 3 (PRSS1/2/3), and the urokinase-type plasminogen activator (uPA). These enzymes are expressed in many cancers, especially during tissue remodeling and subsequent tumor cell invasion. Opaganib (ABC294640), a novel, orally available small molecule is a selective inhibitor of the phosphorylation of sphingosine to sphingosine-1-phosphate (S-1-P) by sphingosine kinase 2 (SPHK2). Both sphingosine kinase 1 (SPHK1) and SPHK2 are known to regulate the proliferation-inducing compound S-1-P. However, SPHK2 is more critical in cancer pathogenesis. The goal of this project was to investigate the potential antitumor effects of upamostat and opaganib, individually and in combination, on cholangiocarcinoma (CCA) xenografts in nude mice. PAX165, a patient-derived xenograft (PDX) from a surgically resected CCA, expresses substantial levels of SPHK2, PRSS1, PRSS2, and PRSS3. Four groups of 18 mice each were treated with upamostat, opaganib, both, or vehicle. Mouse weights and PAX165 tumor volumes were measured. Tumor volumes in the upamostat, opaganib, and upamostat plus opaganib groups were significantly decreased compared to the control group.

Background: Opaganib, an oral sphingosine kinase-2 inhibitor with antiviral and anti-inflammatory properties, was shown to inhibit severe acute respiratory syndrome coronavirus 2 replication in vitro. We thus considered that opaganib could be beneficial for moderate to severe coronavirus disease 2019 (COVID-19) pneumonia. The objective of the study was to evaluate the safety of opaganib and its effect on supplemental oxygen requirements and time to hospital discharge in COVID-19 pneumonia hospitalized patients requiring supplemental oxygen., Methods: This Phase 2a, randomized, double-blind, placebo-controlled study was conducted between July and December 2020 in 8 sites in the United States. Forty-two enrolled patients received opaganib (n = 23) or placebo (n = 19) added to standard of care for up to 14 days and were followed up for 28 days after their last dose of opaganib/placebo., Results: There were no safety concerns arising in this study. The incidence of ≥Grade 3 treatment-emergent adverse events was 17.4% and 33.3% in the opaganib and placebo groups, respectively. Three deaths occurred in each group. A numerical advantage for opaganib over placebo was observed in in this nonpowered study reflected by total supplemental oxygen requirement from baseline to Day 14, the requirement for supplemental oxygen for at least 24 hours by Day 14, and hospital discharge., Conclusions: In this proof-of-concept study, hypoxic, hospitalized patients receiving oral opaganib had a similar safety profile to placebo-treated patients, with preliminary evidence of benefit for opaganib as measured by supplementary oxygen requirement and earlier hospital discharge. These findings support further evaluation of opaganib in this population., (© The Author(s) 2022. Published by Oxford University Press on behalf of Infectious Diseases Society of America.)

Introduction: To determine the 1-year survival, response rate, and toxicity for patients with limited stage small cell lung cancer treated with the combination of cisplatin plus etoposide plus paclitaxel with delayed concurrent (starting with cycle 3) high dose thoracic radiotherapy., Patients and Methods: Patients with previously untreated limited stage small cell lung cancer, Easter Cooperative Oncology Group performance status of 0-2 and adequate organ function were eligible. Cycles 1 and 2 of chemotherapy consisted of paclitaxel 170 mg/m intravenous day 1, etoposide 80 mg/m intravenous days 1 to 3, and cisplatin 60 mg/m intravenous day 1 followed by filgrastim 5 microg/kg subcutaneously days 4 to 13. Cycles 3 and 4 of chemotherapy consisted of a reduced dose of paclitaxel 135 mg/m intravenous day 1, and the same dose of etoposide and cisplatin with concurrent thoracic radiation therapy 1.8 Gy in 35 fractions (total 63 Gy) administered over 7 weeks., Results: Sixty-three patients were entered, 61 patients were eligible. The most common grade 4 toxicity seen was granulocytopenia (62%). Nonhematologic toxicities included febrile neutropenia in 19% of patients, grade 3 and 4 esophagitis in 32% of patients, and grade 3 peripheral neuropathy in 14% of patients. Two patients suffered lethal toxicities. The overall response rate was 79%. The 1-year survival rate was 64%. The median overall survival was 15.7 months, and the median progression-free survival was 8.6 months., Conclusions: The combination of cisplatin plus etoposide plus paclitaxel chemotherapy and concurrent delayed thoracic radiotherapy as administered in this trial provide no apparent advantage with respect to response, local control, or survival compared with historical controls.

Aims and Background: To analyze the efficacy and toxicity of adjuvant chemotherapy followed by whole abdominal irradiation in the treatment of resectable gastric cancer with positive lymph nodes., Methods and Study Design: Between 1996 and 1999, 10 patients with node-positive gastric cancer underwent complete gross resection and were treated by postoperative chemoradiotherapy. The chemotherapy regimen consisted of 5-fluorouracil, 1000 mg/m2/day as a 96-hr continuous infusion on day 1, and cisplatin, 100 mg/m2 on day 2, every 21 days. Six courses were planned. Radiotherapy was administered 3 weeks after completion of the chemotherapy protocol as a single-fraction dose of 600 cGy in a two-field (anterior and posterior) configuration., Results: Treatment was generally well tolerated, with no treatment-related deaths. However, 9 of the 10 patients died of recurrent disease, with a median survival of 20 months (range, 7-84)., Conclusions: Adjuvant chemotherapy with whole abdominal irradiation for gastric cancer is safe and tolerable but has no apparent effect on patient outcome. Studies in larger series are needed to evaluate the role of the approach in this disease.

Objective: To determine whether the use of adjuvant radiation in the treatment of invasive thymic tumors affects survival and to identify prognostic factors., Methods: The files of 47 patients with thymic tumors treated by adjuvant radiation in our institute from 1984 to 2003 were reviewed for data on prognosis and survival. All patients underwent thoracotomy followed by either total macroscopic resection (n = 42) or biopsy (n = 5). The radiation dose ranged from 26 to 60 Gy., Results: Median duration of follow-up was 10.6 years. Overall 5-year survival was 73% (60%-88%): 77% for thymoma (n = 35/45) versus 33% for thymic carcinoma (n = 2/6) (P = 0.14). Better survival was associated with lower disease stage (II vs. III/IVA, P = 0.01), resection (P = 0.0004), myasthenia gravis at presentation (P = 0.04), and higher radiation dose (45 Gy, P = 0.02); sex, smoking, tumor size, pathology, and margin status had no effect. Locoregional relapse occurred in 11 patients and distant metastasis in 4. The 5-year disease-free survival was 67% (52%-86%), with a median time to recurrence of 8.3 years. The better overall survival and disease-free survival associated with higher doses of radiation were also true for stage II patients. On multivariate analyses after adjusting for age, higher disease stage and lower radiation dose were found to adversely affect overall survival and disease-free survival. Thymic carcinoma had an impact only on disease-free survival., Conclusion: Postoperative radiation therapy to doses above 45 Gy may improve the disease-free and overall survival of patients with invasive thymoma, especially stage II. Thymic carcinoma has a worse prognosis.

Purpose: To define the maximum tolerated dose (MTD) and the nature of the toxicities associated with gemcitabine given as a short infusion to patients with non-small cell lung cancer (NSCLC). Secondary objectives were to monitor immunologic response, clinical response, and survival., Patients and Methods: Thirty-two patients diagnosed with advanced inoperable NSCLC and performance status of 0 or 1 participated in this study. Patients consisted of 22 males and 10 females whose median age was 62 years (range 32-79). Gemcitabine was administered as a 30 min infusion once weekly for 3 weeks followed by 1 week of rest. Patients were enrolled at six gemcitabine dose levels ranging from 1000 to 3500 mg/m2. Patients completed a median of four cycles (range 1-17). Responses were evaluated after every two cycles., Results: Toxicity was evaluated in all 32 patients. The MTD was not reached as gemcitabine was well tolerated at all dose levels. Grade 4 toxicity occurred in three (9%) patients: pulmonary and lymphocytopenia in one patient each, and both neurocortical and cardiac in one patient. Grade 3 toxicity was found in a total of 20 (63%) patients: pulmonary in 10 (31%) patients; pain in 6 (19%) patients; liver toxicity in 6 (19%) patients; leukopenia and lymphocytopenia in 5 (16%) patients each; anemia, nausea, and cardiac toxicity in 3 (9%) patients each; proteinuria and infection in 2 (6%) patients each; and hemorrhage in 1 (3%) patient. Of the 29 patients evaluable for response, seven objective responses were achieved: six at the 2200 mg/m2 dose level and one at the 2800 mg/m2 dose level. The distribution of responses differed significantly by dose (P = 0.0124 by the exact chi-square test for independence). The overall response rate was 24.1% (95% CI, 10.3-43.5%). At 6 h post-infusion, there was a significant increase in spontaneous tumor necrosis factor (TNF) release and stimulated interleukin (IL)-2 production, and significant decreases in total white blood cell and lymphocyte counts (CD3+, CD8+, and CD16+ lymphocytes) and resting and stimulated superoxide production by formyl-methionyl-leucyl-phenylalanine (fMLP), phorbol myristate acetate, and opsonized zymosan (OPS-Z). At 24 h post-infusion, there were significant decreases in total lymphocyte count, lymphocyte subsets (CD3+, CD4-, CD8+, CD56+, CD19+), and in resting and stimulated superoxide production by fMLP and OPS-Z. There also appeared to be an association between the levels of spontaneous TNF release and the severity of both gastrointestinal (GI) and pulmonary toxicities., Conclusion: Gemcitabine given as a short infusion was well tolerated at the dose levels of 1000-3500 mg/m2. The MTD was not reached. Toxicities appeared to be cumulative with multiple cycles. Gemcitabine appears to have activity against NSCLC. Although there was a differential dose-response rate among dose levels, increasing the gemcitabine dose beyond 2200mg/m2 did not show increased clinical response. Gemcitabine appears to modulate the immune response, which may in turn mediate both response and toxicity, although no statistically significant correlation between immune and clinical response was detected.

Forty-four specimens of non-malignant and malignant human lung tissue, taken from patients with non-small cell lung cancer (NSCLC), were examined for the expression of wild-type p53, mutant p53, and bcl-2 and the occurrence of programmed cell death (apoptosis). Wild-type p53 expression peaked in peritumoral and metaplastic samples, whereas mutant p53, bcl-2 and apoptosis were first detected in metaplasia and increased with progression to carcinoma. Bcl-2 positive samples had lower levels of apoptosis than bcl-2 negative samples and was independent of wild-type or mutant p53 expression. These results suggest that the over-expression of wild-type p53 may be an early cellular response to an alteration in normal cellular homeostasis. The ensuing increase in apoptosis appears to be relatively independent of mutant or wild-type p53 expression, but does not occur in cells expressing bcl-2.

Ceramide has been proposed as a second messenger for stress-induced apoptosis. By characterization of murine melanoma cells and their E1A transfectants, we found several lines of evidences against the role of ceramide as a second messenger for ultraviolet (UV)-induced apoptosis. First, although E1A transfected melanoma cells were more sensitive to UV-induced apoptosis than parental cells, the relative endogenous ceramide elevation induced by UV was greater in parental cells than in E1A transfectants. Second, UV-resistant melanoma cells were more sensitive to exogenous ceramide than UV-sensitive E1A transfectants. The differential responses to UV and ceramide by E1A require the same functional CR2 domain of E1A. Third, unlike the action of UV, transient exposure (up to 2 h) of lethal dose of ceramide was not sufficient to cause apoptosis in these cells, and persistent presence of ceramide was required for processing the apoptotic process. Finally, ceramide and UV do not share a common pathway in apoptosis induction. UV-induced apoptosis was blocked by interleukin-1beta-converting enzyme (ICE) inhibitor z-VAD whereas ceramide-induced apoptosis was not. Therefore, we conclude that ceramide is not a general second messenger for UV-induced apoptosis.

Background: Retinoids represent a potentially useful class of drugs in the chemoprevention and treatment of cancer, due to their ability to regulate cell proliferation and differentiation. However, there is controversy in the literature about the effects of all-trans retinoic acid (ATRA) in non- small cell lung cancer (NSCLC). In this study we examined the effects of ATRA on apoptotic death in NSCLC., Materials and Methods: Cell proliferation was determined by thymidine incorporation in cultured NSCLC cells. DNA fragmentation was measured in NSCLC cell lines as a marker of apoptosis. The expression of keratinocyte transglutaminase and cytokeratin 10 were measured as markers of squamous differentiation., Results: ATRA inhibited cell proliferation, and induced markers of both apoptosis and squamous differentiation after 24-48 hrs of treatment., Conclusions: These results indicate the possibility of the early growth-inhibitory and apoptotic effects of ATRA in NSCLC which may result in selection of ATRA-resistant cells.

Interleukin-15 (IL-15) is a pleiotropic cytokine that induces the generation and differentiation of lymphoid cells and shares many biological activities with IL-2. We have shown here the development of dendritic cells (DC) from human CD34+ hemopoietic precursor cells cultured for 2-4 weeks with IL-15 alone. DC generated with IL-15 have typical morphological, immunocytochemical, phenotypic, and functional characteristics of mature DC. Dual flow cytometry analysis performed weekly demonstrated increasing co-expression of CD1a or CD83 with HLA-DR, CD80, CD86, IL-2R alpha, beta, and gamma. Two populations of cells were distinguished among CD34+ progeny. Small and medium-size cells were mainly natural killer (NK) cells (72.6-85.2% CD56+) and low numbers of DC (9.1-21.3% CD1a+). Large cells were mostly DC (75.4-95.4% CD1a+). Isolated CD34+ cells did not express IL-2R subunits but after 2-3 days in culture with IL-15, they were found to express IL-2Rgamma. Induced expression of IL-2Rgamma on CD34+ cells may explain the primary mechanism of IL-15-regulated differentiation of hemopoietic precursor cells. Thus, our data suggest that IL-15 stimulates CD34+ cells to differentiate into NK and DC and may represent a new growth and survival factor for lymphoid DC.

Tissue transglutaminase is a multifunctional enzyme which has been involved in the regulation of cell growth, differentiation, and apoptosis. Recently, nuclear localization of tTG has been reported indicating the potential of active nuclear transport. In this study we use the yeast two-hybrid assay and co-immunoprecipitation to show that tTG interacts with the nuclear transport protein importin-alpha3. Using electron microscopy we demonstrate that nuclear expression of tTG in a non-small cell lung cancer cell line is induced by retinoic acid (RA). These data suggest that importin-alpha3 could mediate active nuclear transport of tTG which may be important for the regulation of critical cellular processes.

Tissue transglutaminase (tTG) and keratinocyte transglutaminase (kTG), as well as the cross-linked envelopes (CLE) that they form, have been associated with squamous differentiation and programmed cell death in epithelial cells. When interferon-beta (IFN-beta) was used to stimulate differentiation and programmed cell death in the human lung cancer cell lines NCI-H596 and NCI-H226, the cells underwent a decrease in cellular density. In NCI-H596 IFN-beta caused an increase in kTG activity and DNA fragmentation in the lower density cells, which were significantly slower growing than control cells. However, in the higher density cells, which were only slightly slower growing than control cells, IFN-beta caused an increase in tTG activity and CLE competence. Dual-parameter flow cytometry demonstrated that IFN-beta-induced squamous differentiation preceded programmed cell death. Treatment of NCI-H596 cells with monodansylcadaverine, a transglutaminase inhibitor, prevented the increase in CLE competence, but did not inhibit DNA fragmentation. These results suggest that IFN-beta can induce NCI-H596 cells to enter multiple cell death pathways and that these pathways are not only differentiation related, but may also be growth driven., (Copyright 1999 Academic Press.)

Programmed cell death (PCD) is a genetically regulated pathway that is altered in many cancers. This process is, in part, regulated by the ratio of PCD inducers (Bax) or inhibitors (Bcl-2). An abnormally high ratio of Bcl-2 to Bax prevents PCD, thus contributing to resistance to chemotherapeutic agents, many of which are capable of inducing PCD. Non-small cell lung cancer (NSCLC) cells demonstrate resistance to these PCD-inducing agents. If Bcl-2 prevents NSCLC cells from entering the PCD pathway, then reducing the amount of endogenous Bcl-2 product may allow these cells to spontaneously enter the PCD pathway. Our purpose was to determine the effects of bcl-2 antisense treatment on the levels of programmed cell death in NSCLC cells. First, we determined whether bcl-2 and bax mRNA were expressed in three morphologically distinct NSCLC cell lines: NCI-H226 (squamous), NCI-H358 (adenocarcinoma), and NCI-H596 (adenosquamous). Cells were then exposed to synthetic antisense bcl-2 oligonucleotide treatment, after which programmed cell death was determined, as evidenced by DNA fragmentation. Bcl-2 protein expression was detected immunohistochemically. All three NSCLC cell lines expressed both bcl-2 and bax mRNA and had functional PCD pathways. Synthetic antisense bcl-2 oligonucleotide treatment resulted in decreased Bcl-2 levels, reduced cell proliferation, decreased cell viability, and increased levels of spontaneous PCD. This represents the first evidence that decreasing Bcl-2 in three morphologically distinct NSCLC cell lines allows the cells to spontaneously enter a PCD pathway. It also indicates the potential therapeutic use of antisense bcl-2 in the treatment of NSCLC.

Epidermal growth factor receptor (EGFR) is a 170 kD transmembrane glycoprotein with tyrosine kinase activity. Overexpression of the EGFR has been detected in many human cancers, including non-small cell lung cancer (NSCLC), and is correlated with poor prognosis and chemoresistance. We investigated the effects of tyrosine kinase inhibitors on chemosensitivity and chemotherapeutic drug-induced programmed cell death in NSCLC cell lines that express different levels of EGFR. NCI-H596 cells, which strongly express EGFR, were more resistant to the growth inhibitory effects of cisplatin, doxorubicin and etoposide than were NCI-H358 cells, which only weakly express EGFR. Both genistein, a general tyrosine kinase inhibitor, and tyrphostin AG 1478, a tyrosine kinase inhibitor specific for EGFR, inhibited phosphorylation of EGFR in NCI-H596. Combinations of genistein or tyrphostin AG 1478 with cisplatin, doxorubicin, or etoposide enhanced the antiproliferative effects and induced programmed cell death in NCI-H596 cells, whereas no such additive effects were observed in NCI-H358 cells. The programmed cell death induced by these agents involved CPP32 mediated PARP cleavage and DNA fragmentation. These results indicate that tyrosine kinase inhibitors in combination with chemotherapeutic drugs may prove to be a viable therapeutic strategy for the treatment of those types of NSCLC that demonstrate strong expression of EGFR.

Purpose: Suramin, a polysulfonated naphthylurea, has been shown to be effective in the treatment of several cancers. We have reported that suramin, at dose concentrations higher than 140 microM, exerts growth-stimulatory effects in several non-small-cell lung cancer (NSCLC) cell lines. The purpose of this study was to examine the mechanisms by which suramin exerts this growth-stimulatory effect in NSCLC cells., Methods: NCI-H596 cells were treated with agarose-immobilized suramin, directly or by addition on cell culture inserts, after which growth was determined by [3H]thymidine incorporation. PPADS, a specific purinergic receptor antagonist, was used to determine whether suramin acts via purinergic receptors. The effect of suramin on epidermal growth factor receptor (EGFR) was determined by analyzing receptor phosphorylation and dimerization. XAMR 0721, a suramin analogue containing only one of the two polysulfonated arms, was also analyzed for its effects on growth and EGFR activation., Results: Agarose-immobilized suramin stimulated NCI-H596 cell growth, but only when added directly to the cells. When the suramin-conjugated beads were added to the cells on cell culture inserts, which preclude an interaction with the cell surface but allow interaction with the culture medium, there was no effect on proliferation. PPADS had no effect on the growth stimulation by suramin; however suramin treatment resulted in rapid phosphorylation and dimerization of EGFR. Treatment with XAMR 0721 did not affect growth or tyrosine phosphorylation and dimerization of EGFR., Conclusions: Suramin need not enter NCI-H596 cells to exert its growth-stimulatory effect, nor is this effect mediated by an interaction with soluble growth factors. Rather, it appears that suramin acts via an interaction with EGFR, but not with purinergic receptors.

Due to the limited efficacy of cytotoxic chemotherapy in the treatment of advanced malignancy and its excessive toxicity precluding its use in chemoprevention, new therapeutic and preventive strategies have been sought. One of the most interesting of these new approaches is the manipulation of signal transduction pathways. Among the approaches being considered to eventuate such a strategy is the inhibition of autophosphorylation, a critical first step in the signal transduction pathways of many cell surface receptor tyrosine kinases, as well as of non-receptor tyrosine kinases. This article is intended to review those tyrosine kinase inhibitors that are currently in preclinical development, for which there are data to support consideration for their use in chemoprevention or cancer treatment. We will focus upon those agents that have received attention in the past several years.

Fifty samples of lung tissue from patients with non-small cell lung cancer were analyzed for the expression and localization of biomarkers related to squamous differentiation and programmed cell death. These markers include tissue transglutaminase (tTG), keratinocyte transglutaminase (kTG), involucrin, loricrin, and Bcl-2. We found that all of these markers are overexpressed in tumors as compared with histologically normal lung epithelium, where expression is minimal. Expression of the oncoprotein, Bcl-2, increased starting in squamous metaplasia and remained elevated in all lesions, including frank carcinoma. In contrast, expression of the other markers was elevated in the histologically abnormal noninvasive lesions but was decreased somewhat in invasive malignancy. In addition, we found that tTG, kTG, and Bcl-2, when expressed, were detected in mutually exclusive areas. These findings suggest that (1) these markers may prove useful, with more extensive testing and clinical correlation, in predicting risk for the development of lung cancer; and (2) pulmonary carcinogenesis may result from the failure of differentiation and programmed cell death mechanisms in the presence of oncogene overexpression rather than through oncogene/tumor suppressor gene abnormalities alone.

Dendritic cells (DC) have been shown to develop along a myeloid or lymphoid lineage of differentiation propagated from bone marrow or early thymic precursor cells with hematopoietic cytokines. In our study, we have induced growth and differentiation of DC from cord blood CD34+ cells initiated in interleukin-2 (IL-2) alone or in IL-2 + stem cell factor (SCF) + tumor necrosis factor alpha (TNF-alpha)-supplemented medium and cultured with IL-2 or IL-2 + SCF for 28-35 days. Dendritic morphology and antigenic phenotype of DC grown with IL-2 were characteristic for DC cultured in the presence of granulocyte-macrophage colony-stimulating factor (GM-CSF). Growth and differentiation of DC was followed by an increase in expression of MHC II and co-stimulating molecules CD80 and CD86. We have also shown the expression of the IL-2 receptor (IL-2R) gamma-chain in CD34+ cells after 2-3 days of culture with IL-2 alone. The co-expression of the IL-2R alpha, beta, and gamma subunits in both DC cultured with IL-2- or GM-CSF-containing cocktail of cytokines was also shown. The time curve for induction of IL-2R demonstrated low levels of subunit expression at the beginning of culture. The number of CD1a cells co-expressing CD25, CD122, and CDgamma increased to about 24-68 and to 78-95% after 21 and 28-35 days, respectively. Development of natural killer cells was shown along with DC. The proportion of CD56+ cells and cytotoxicity increased in a time-dependent manner.

EGF receptor (EGFR) is a transmembrane glycoprotein with trosine kinase activity that is overexpressed in many human cancers, including lung. In the present study, we evaluated the effect of EGF and genistein, a tyrosine kinase inhibitor, on cell proliferation, EGFR phosphorylation and its downstream signal MAP kinase activation and investigated the involvement of these processes in programmed cell death in a human pulmonary adenosquamous carcinoma cell line, NCI-H596. Treatment with EGF resulted in phosphorylation of EGFR, activation of MAP kinase, phosphorylation of ERK 2 (an isoform of MAP kinase), increased cell proliferation and induction of cross-linked envelope (CLE) competence. Genistein abolished the ability of EGF to induce EGFR phosphorylation, to activate MAP kinase and to increase cell proliferation. Genistein alone stimulated CLE competence, but apparently by a different mechanism than EGF since genistein prevented EGF-stimulated CLE competence. The genistein-stimulated CLE competence was accompanied by a decrease in cell proliferation and increased DNA fragmentation. These results demonstrate that genistein antagonizes growth stimulatory EGF signaling upstream of MAP kinase and may simultaneously stimulate an apoptotic pathway. Furthermore, EGF appears to stimulate an alternate, growth related programmed cell death pathway, not involving DNA fragmentation, but characterized by rapid proliferation and genistein-sensitive CLE competence.

Non-small cell lung cancer (NSCLC) is fatal in approximately 90% of all cases due to the failure of systemic therapy, secondary to resistance to chemotherapy. In such malignancies new therapeutic paradigms are needed. One such approach takes advantage of normal physiologic growth regulatory mechanisms, such as terminal cellular differentiation or apoptosis. Suramin, as an antineoplastic drug, has shown efficacy in the treatment of prostate cancer and is capable of promoting differentiation in several human cancer cell lines. Little is known about the differentiating effects of suramin in lung cancer. In the present investigation we evaluated the ability of suramin to induce cross-linked envelope (CLE) formation, as a common marker for squamous differentiation and apoptosis, in three representative human non-small cell lung cancer cell lines: NCI-H226 (squamous), NCI-H358 (bronchoalveolar [adenocarcinoma]), and NCI-H596 (adenosquamous). Among agents that we have tested, suramin demonstrated the unique ability to induce spontaneous CLE formation in the two cell lines with squamous features, NCI-H226 and NCI-H596. Suramin induced CLE formation was accompanied by DNA fragmentation, a marker for apoptosis, in NCI-H596 and NCI-H358, but not in NCI-H226. Stimulation of CLE formation by suramin correlated with the rapid induction of both type II transglutaminase (TG) activity and involucrin expression. These parameters were protein synthesis independent, suggesting posttranslational mechanisms of suramin activity. Induction of differentiation/apoptosis markers by suramin did not correlate with its effect on growth. Modulation of signal transduction is a likely candidate mechanism for suramin activity in lung cancer. The relationship between growth, squamous differentiation, and apoptosis is considered.

Based upon in vitro and clinical data suggesting antitumor activity of interleukin-2 (IL-2) plus tumor necrosis factor (TNF) in non-small cell lung cancer (NSCLC), we conducted two parallel pilot studies of the combination in patients with advanced disease. Eight patients at the University of Wisconsin received 6 x 10(6) international U/m2/day of IL-2 by continuous infusion on days 1-4, 8-11, and 15-18 with 50 micrograms/m2/day of TNF administered intramuscularly on the same days. Seven patients at the University of Pittsburgh received IL-2 as a continuous infusion for 5 days at a dose of 6 x 10(6) U/m2/day, every 14 days. TNF was administered intramuscularly on days 1 through 5, starting at a dose of 50 micrograms/m2. Patients with no evidence of grade 3 or 4 toxicity on the first cycle had their dose of TNF escalated from 50 to 100 and then to 150 micrograms/m2. No responses were observed. The therapy was not well tolerated, with 11 of 15 patients developing grade 3 or 4 toxicity at some point during their therapy. The most common grade 3 or 4 toxicities were pulmonary (6 episodes) or cardiac (4 episodes) events. Constitutional symptoms were common, but not dose-limiting. Despite the lack of observed responses, the median survival was 11 months, with one patient with metastatic disease alive over 30 months later. We conclude that IL-2 plus TNF was not effective in inducing responses in patients with advanced NSCLC, but the prolonged survival suggests a role for IL-2 in NSCLC, which needs to be further defined by means other than classic response criteria.

Background: Non-small-cell lung cancer (NSCLC) is one of the leading causes of cancer-related mortality due largely to the failure of systemic chemotherapy. Thus, new therapeutic paradigms involving the manipulation of normal physiologic growth-regulatory mechanisms, such as terminal cellular differentiation or programmed cell death, are being explored. Interferons may function as antineoplastic agents, in part because of their effects on cell proliferation and differentiation. We have previously demonstrated the antiproliferative and differentiating effects of interferon beta (IFN beta)., Purpose: The present investigation was designed to study the mechanism of IFN beta on squamous differentiation and/or programmed cell death in cultured NSCLC cells., Methods: Cross-linked envelope competence and transglutaminase expression and activity were measured in three NSCLC cell lines (NCI-H226, NCI-H358, and NCI-H596) as common markers for squamous differentiation and programmed cell death. DNA fragmentation, as determined by gel electrophoretic analysis, served as a marker for programmed cell death. In addition, the expression of several regulatory and differentiation-related genes (measured by Northern blot analysis of messenger RNA levels) as well as protein kinase C activity was measured to begin to explore possible mechanisms of IFN beta activity., Results: IFN beta-induced cross-linked envelope competence occurred in cell lines with squamous features (NCI-H226 and NCI-H596); conversely, DNA fragmentation occurred in cell lines with glandular features (NCI-H358 and NCI-H596). Stimulation of cross-linked envelope competence by IFN beta was associated with the induction of tissue transglutaminase activity. Both of these parameters were protein-synthesis independent. As previously observed for NCI-H596, IFN beta suppressed the growth of the other two cell lines. Total protein kinase C activity was not altered. Expression of a variety of possibly relevant oncogenes and other genes was variably altered by IFN beta., Conclusions: IFN beta induces programmed cell death in NSCLC cell lines in a phenotype-specific manner. The programmed cell death pathway represented by cross-linked envelope competence is dependent on the expression of the squamous phenotype and is protein-synthesis independent, suggesting post-translational mechanisms. In addition, squamous differentiation itself may be induced. Changes in gene expression, while not necessary for induction of cross-linked envelope competence, may be involved in other aspects of cellular homeostasis, such as growth suppression., Implications: By inducing terminal cellular differentiation or programmed cell death, IFN beta may be therapeutically useful in NSCLC. The post-translational nature of IFN beta-induced effects suggests that it will be best used in combination with other agents that can regulate these cellular pathways at the pretranslational level, increasing the proportion of cells capable of being driven to a terminal state by this biotherapeutic agent.

Lung carcinoma cell lines were analyzed in culture and in nude mouse xenograft for both morphological appearance and expression of specific proteins that participate in cross-linked envelope formation during normal squamous cell terminal differentiation. Cross-linked envelope formation, induced by artificial influx of millimolar Ca2+ into the cultured cells, was an exclusive trait of squamous, adenosquamous, and mucoepidermoid carcinomas. Small cell lung carcinoma and non-squamous non-small cell lung carcinoma lines, such as adenocarcinoma and large cell carcinoma, were uniformly negative for cross-linked envelope formation. Involucrin, which is incorporated into the cross-linked envelope by the enzyme transglutaminase, was expressed at highest levels in squamous tumors, but several of the non-squamous non-small cell lung carcinoma lines also expressed comparable amounts. On the other hand, transglutaminase activity was consistently higher in squamous as opposed to non-squamous lines, so that in cell culture, a clear contrast between the groups could be observed. A Mr 195,000 protein that is incorporated into cultured human epidermal cell cross-linked envelopes was also observed in some but not all of the squamous lines. Two forms of transglutaminase are expressed in cultured keratinocytes. One of them, tissue transglutaminase, was expressed in the majority of squamous cell lines even though it is not a normal product of squamous differentiation in vivo. Keratinocyte transglutaminase, which is distinct from the tissue form and is normally expressed during terminal differentiation in squamous epithelia. was measurably present in only one of the six squamous cell lines tested. In nude mouse xenografts, keratinocyte transglutaminase, localized immunohistochemically with a biotinylated mouse monoclonal antibody, was again present only in a minority of the squamous lines whereas involucrin was expressed in all. In contrast to involucrin, keratinocyte transglutaminase is not an obligatory component of squamous differentiation in the pulmonary carcinoma cell lines tested. Its expression may be of value in further refining their classification.

Attempts were made to establish lymphoid cell lines from the cultured peripheral blood lymphocytes of six patients with chronic lymphocytic leukemia. In only one case was cell growth obtained following the addition of exogenous transforming Epstein-Barr virus, and those cell cultures proved not to have acquired the ability to proliferate permanently. In the same case, cell lines were established spontaneously from the peripheral blood without addition of Epstein-Barr virus. The cells which grew spontaneously were large, were occasionally weakly surface adherent, and grew in suspension as loose clumps or as single cells. They were negative for surface immunoglobulins and spontaneous rosette formation with sheep erythrocytes and positive for intracytoplasmic immunoglobulins (Fc and C3 receptors). At an early passage, the spontaneous lines had an aneuploid karyotype with some triploid and some tetraploid cells. Structural chromosomal aberrations include a 14q+. Electron microscopy of the chronic lymphocytic leukemia lines revealed relatively smooth surfaces with numerous mitochondria, widespread vacuolization, and numerous unusual "myelin" figures. Five to 10% of the cells were phagocytic as detected by internalization of latex particles; however, they were Epstein-Barr nuclear antigen positive. The nature of these cells and their possible relationship to the etiology of chronic lymphocytic leukemia are discussed.

Combinations of cytotoxic agents that cure a substantial percentage of patients with several childhood and adult malignancies are much less efficacious for the majority of solid tumors. Standard approaches for curability that rely solely on the concept of cytotoxicity may not be applicable for most epithelial and mesenchymal solid malignancies. Differentiation may play a more important role in cancer cure than heretofore suspected. Clinical and experimental evidence supports further investigation into models of inducing tumor cell differentiation. The question of why such models could predict for curative modalities of treatment is discussed.

X-Ray survival curves were determined using a panel of 17 human lung cancer cell lines, with emphasis on non-small cell lung cancer (NSCLC). In contrast to classic small cell lung cancer (SCLC) cell lines, NSCLC cell lines were generally less sensitive to radiation as evidenced by higher radiation survival curve extrapolation numbers, surviving fraction values following a 2 Gy dose (SF2) and the mean inactivation dose values (D) values. The spectrum of in vitro radiation responses observed was similar to that expected in clinical practice, although mesothelioma was unexpectedly sensitive in vitro. Differences in radiosensitivity were best distinguished by comparison of SF2 values. Some NSCLC lines were relatively sensitive, and in view of this demonstrable variability in radiation sensitivity, the SF2 value may be useful for in vitro predictive assay testing of clinical specimens.