Collection of peripheral blood progenitor cells on Day 4 is feasible and effective while reducing granulocyte-colony-stimulating factor exposure to healthy donors.

BACKGROUND: Peripheral blood progenitor cells (PBPCs) are the most common stem cell source for allogeneic transplantations. Analysis of our collection data obtained with a Spectra Optia device (Terumo) for apheresis demonstrated collection efficacies (CEs) exceeding our internal target levels of 5 × 10(6) CD34+ cells/kg body weight of the recipient when collected on Day 5. We thus aimed to investigate whether collection on Day 4 would lead to adequate amounts of PBPCs while minimizing granulocyte-colony-stimulating factor (G-CSF) exposure in healthy donors. STUDY DESIGN AND METHODS: We compared feasibility and effectiveness of Day 5 versus Day 4 collections with data obtained from 23 and 18 allogeneic procedures, respectively. RESULTS: Both groups were comparable with regard to donor and collection characteristics. Product characteristics as well as platelet loss, CE, throughput, and collection rate did not differ between both protocols. A higher contamination with white blood cells (WBCs; ×10(9) /L) was observed in products collected on Day 5 compared to Day 4 (231 [range, 181-299] vs. 203 [range, 165-239]; p = 0.004). A second apheresis procedure was required in three of 23 patients and three of 18 patients, respectively (p = 0.6) to obtain the required PBPC dose. CONCLUSIONS: PBPC apheresis on Day 4 seems as feasible and effective as collection on Day 5. Collection on Day 4 produces lower WBC content in the product and allows a reduction in G-CSF exposure to healthy donors.

Stimulation of the aberrant expression of a paraneoplastic antigen, recoverin, in small cell lung cancer cell lines.

Recoverin, a retina-specific Ca2+-binding protein, is one of the paraneoplastic antigens (PNAs) which are normally present in neurons, but can also be aberrantly expressed in malignant tumors localized outside the nervous system. In this study, we have analyzed 16 small cell lung carcinoma (SCLC) and 12 non-small cell lung carcinoma cell lines and found that none of them is capable of expressing recoverin in vitro. However, two small cell lung carcinoma lines, NCI-H69 and NCI-H82, became recoverin-positive after cultivation in the presence of butyrate. Recoverin expression in the butyrate-treated cells has been detected by immunoblotting with polyclonal (monospecific) antibodies against recoverin and confirmed by the analysis of recoverin mRNA expression. To our knowledge, this work is the first to demonstrate stimulation of the aberrant expression of recoverin in cancer cell lines in vitro. This result opens the way to investigation of the mechanisms underlying the aberrant expression of recoverin, as well as other paraneoplastic antigens, in tumor cells.

Recoverin as a paraneoplastic antigen in lung cancer: the occurrence of anti-recoverin autoantibodies in sera and recoverin in tumors.

Using immunoblotting with recombinant recoverin as an antigen, we have examined 279 serum samples from individuals with small cell lung carcinoma (SCLC, 99 patients), non-small cell lung carcinoma (NSCLC, 44 patients), and non-malignant pulmonary disorders (86 patients) as well as sera from 50 healthy donors. Autoantibodies against recoverin (anti-Rc) were detected in sera from 15 patients with SCLC (15% of cases) and from 9 patients with NSCLC (about 20% of cases). Only two anti-Rc positive cases were detected in patients with non-malignant pulmonary disorders, while no such cases were found in healthy individuals. Immunohistochemical investigation of paraffin sections of 44 SCLC and 40 NSCLC tumors revealed recoverin-positive reaction in 30 SCLC (68%) and 34 NSCLC (85%) sections. Despite the high specificity (98%), the low sensitivity (less than 20%) does not allow serum anti-Rc to be considered as a valuable marker of lung cancer. However, taking into account the high occurrence of aberrant expression of recoverin in lung tumors, this PNA could be considered as a potential target for immunotherapy of lung cancer.

Is growth inhibition and induction of apoptosis in lung cancer cell lines by fenretinide [N-(4-hydroxyphenyl)retinamide] sufficient for cancer therapy?

The synthetic retinoid fenretinide [N-(4-hydroxyphenyl)retinamide, 4-HPR] has demonstrated growth inhibition and induction of apoptosis of various malignant cells, including lung cancer cell lines. 4-HPR is now being investigated in several clinical trials. In our study, we show that 4-HPR inhibits growth on a broad panel of lung cancer cell lines (12/12 small cell lung cancer and 9/12 nonsmall cell lung cancer cell lines), including cell lines unresponsive to all-trans-retinoic acid (ATRA). 4-HPR revealed a higher potency than ATRA in inhibiting cell growth with IC(50) values ranging from 3.3-8.5 microM. Furthermore, 4-HPR induces apoptosis in lung cancer cell lines as proven by TUNEL and annexin V assay. Despite this, we observed stimulation of growth in 2 SCLC cell lines at 1 microM 4-HPR. In advance to the clinical application of 4-HPR, we demonstrate that growth inhibition is reversible after removal of 4-HPR and that long-term application is necessary. Through long-term stimulation with 4-HPR, we cultivated 3 resistant cell lines that were still inhibited by 4-HPR after several weeks, however, exhibited almost no apoptosis. These cell lines exhibited morphologic changes, which in the case of the SCLC cell lines suggested differentiation. Our data show that 4-HPR inhibits growth in lung cancer cell lines by varying mechanisms including (i) cytostasis, (ii) apoptosis and (iii) presumably, differentiation. In contrast, the observed growth stimulation, reversibility of growth inhibition and development of resistance to apoptosis make successful cancer therapy uncertain and may limit clinical application of 4-HPR in lung cancer patients, although its inhibitory effects last over several weeks.