Purpose High-dose aldesleukin (HD IL-2) received FDA approval for the treatment of mRCC in 1992, producing a 14% objective response rate (ORR) and durable remissions. Retrospective studies suggested that clinical and pathologic features could predict for benefit. The Cytokine Working Group conducted this prospective trial to validate proposed predictive markers of response to HD IL-2. Experimental Design Standard HD IL-2 was administered to prospectively evaluate whether the ORR of mRCC patients with “good” predictive pathologic features based on an “integrated selection” model (ISM) (e.g. clear-cell histology sub-classification and carbonic anhydrase-9 (CA-9) IHC staining) was significantly higher than the ORR of a historical, unselected population. Archived tumor was collected for pathologic analysis including tumor programmed death-ligand 1 (PD-L1) expression. Results 120 eligible patients enrolled between 11/06 and 7/09; 70% were MSKCC intermediate risk, 96% had clear cell RCC and 99% had prior nephrectomy. The independently assessed ORR was 25% (30/120, 95% CI = 17.5%–33.7%, p=0.0014) (3 CR, 27 PR) and was higher than a historical ORR. Thirteen patients (11%) remained progression-free at 3 years and the median OS was 42.8 months. ORR was not statistically different by ISM classification (“good-risk” 23% vs. “poor-risk” 30%, (p=0.39)). ORR was positively associated with tumor PD-L1 expression (p=0.01) by IHC. Conclusions In this prospective, biomarker validation study, HD IL-2 produced durable remissions and prolonged survival in both “good” and “poor-risk” patients. The proposed ISM was unable to improve the selection criteria. Novel markers (e.g. tumor PD-L1expression) appeared useful, but require independent validation.

The majority of prostate cancers are indolent, whereas a significant portion of patients will require systemic treatment during the course of their disease. To date, only high Gleason scores are best associated with a poor prognosis in prostate cancer. No validated serum biomarker has been identified with prognostic power. Previous studies showed that secretory phospholipase A2-IIa (sPLA2-IIa) is overexpressed in almost all human prostate cancer specimens and its elevated levels are correlated with high tumor grade. Here, we found that sPLA2-IIa is overexpressed in androgen-independent prostate cancer LNCaP-AI cells relative to their androgen-dependent LNCaP cell counterparts. LNCaP-AI cells also secrete significantly higher levels of sPLA2-IIa. Blocking sPLA2-IIa function compromises androgen-independent cell growth. Inhibition of the ligand-induced signaling output of the HER network, by blocking PI3K-Akt signaling and the nuclear factor-kappaB (NF-κB)-mediated pathway, compromises both sPLA2-IIa protein expression and secretion, as a result of downregulation of sPLA2-IIa promoter activity. More importantly, we demonstrated elevated serum sPLA2-IIa levels in prostate cancer patients. High serum sPLA2-IIa levels are associated significantly with high Gleason score and advanced disease stage. Increased sPLA2-IIa expression was confirmed in prostate cancer cells, but not in normal epithelium and stroma by immunohistochemistry analysis. We showed that elevated signaling of the HER/HER2-PI3K-Akt-NF-κB pathway contributes to sPLA2-IIa overexpression and secretion by prostate cancer cells. Given that sPLA2-IIa overexpression is associated with prostate development and progression, serum sPLA2-IIa may serve as a prognostic biomarker for prostate cancer and a potential surrogate prostate biomarker indicative of tumor burden.

SummaryThe effect of IL-6 on in vitro platelet function was investigated. Platelet-rich plasma (PRP) incubated with IL-6 showed a dose dependent enhancement of agonist induced maximum aggregation (AIMA) and secretion of thromboxane B2 (TXB2) as measured by RIA, in short term incubations. Dazoxiben (0.2 to 160 (µM) pretreated PRP incubated with IL-6 and aggregated with ionophore A23187, showed a dose dependent inhibition of TXB2 secretion concomitant with a dose dependent abrogation of IL-6’s enhancement of AIMA. A similar abrogation of AIMA was observed when these experiments were repeated using indomethacin. Further, PRP incubated with IL-6 showed a dose dependent increase in TXB2 and BTG secretion as measured by RIA and an increased incorporation of actin binding protein, talin, and myosin into the cytoskeletal core (triton insoluble residue) as shown by SDS-PAGE. The integrin glycoprotein Ilia (GPIIIa) was also observed to be retained into the cytoskeleton by immunoblot. These results suggest that IL-6 activates platelets in vitro and enhances AIMA via a mechanism involving arachidonic acid metabolism.

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In this study, we preincubated the sera of 3 patients with neuropathies associated with elevated titers of IgM anti-GM1 antibodies, with increasing concentrations of intravenous Ig (IVIg) and assayed the inhibitory effect of this mixture on antibody binding to immobilized GM1 by an enzyme-linked immunosorbent assay. Pharmacologic concentrations of IVIg, ranging from 0.1 microgram/ml to 100 mg/ml, inhibited anti-GM1 binding to its target antigen from 26 +/- 3 to 71 +/- 7%, respectively, in a dose-dependent manner. A similar inhibition of binding was also observed with IVIg F(ab')2 fragments. These findings provide a possible mechanism for the clinical efficacy of IVIg in motor neuropathies.

BACKGROUND Our previous study showed that prostate cancer cells overexpress and secrete secretory phospholipases A2 group IIa (sPLA2-IIa) and plasma sPLA2-IIa was elevated in prostate cancer patients. The current study further explored the underlying mechanism of sPLA2-IIa overexpression and the potential role of sPLA2-IIa as a prostate cancer biomarker. METHODS Plasma and tissue specimens from prostate cancer patients were analyzed for sPLA2-IIa levels. Regulation of sPLA2-IIa expression by Heregulin-α was determined by western blot and reporter assay. RESULTS We found that Heregulin-α enhanced expression of the sPLA2-IIa gene via the HER2/HER3-elicited pathway. The EGFR/HER2 dual inhibitor Lapatinib and the NF-kB inhibitor Bortezomib inhibited sPLA2-IIa expression induced by Heregulin-α. Heregulin-α upregulated expression of the sPLA2-IIa gene at the transcriptional level. We further confirmed that plasma sPLA2-IIa secreted by mouse bearing human prostate cancer xenografts reached detectable plasma concentrations. A Receiver Operating Characteristic (ROC) analysis of patient plasma specimens revealed that high levels of plasma sPLA2-IIa, with the optimum cutoff value of 2.0 ng/ml, were significantly associated with high Gleason score (8~10) relative to intermediate Gleason score (6~7) prostate cancers and advanced relative to indolent cancers. The area under the ROC curve (AUC) was 0.73 and 0.74, respectively. CONCLUSION We found that Heregulin-α, in addition to EGF, contributes to sPLA2-IIa overexpression in prostate cancer cells. Our findings support the notion that high levels of plasma sPLA2-IIa may serve as a poor prognostic biomarker capable of distinguishing aggressive from indolent prostate cancers, which may improve decision making and optimize patient management.

In vitro and in vivo studies have demonstrated that adhesive interactions between tumor cells and platelets may play a central role in the metastatic process. Ultrastructural studies have demonstrated that platelets appear to enhance the development of arrested tumor emboli into a secondary metastatic colony. Platelet adhesive glycoprotein receptors and their immunorelated counterparts expressed by tumor cells participate in tumor-induced platelet aggregation, which may be an early step in the development of a metastatic lesion. Platelet anti-adhesive agents have been demonstrated to reduce metastases in rodent models. Although tumor adhesive glycoproteins have yet to be fully characterized, specific inhibition of their functional sites could constitute a forthcoming strategy for effective inhibition of metastases.

The in vitro effect of IL-6 on platelet activation was investigated. When human platelets were incubated with high (1,000 ng/ml) or low (1 ng/ml) dose IL-6, expression of GMP-140 was enhanced by 42% (N = 6; P < 0.009) and 46% (N = 6; P < 0.061) in 1 hr low and high dose IL-6-platelet incubations, respectively, as assessed by flow cytometry. In platelet specimens incubated with high dose IL-6 for 3 hr, a 70% (N = 6; P < 0.009) increase in GMP-140 expression over control was observed. Parallel high dose IL-6 incubations subjected to scanning electron microscopic studies revealed a 3.4-fold increase (N = 6; P < 0.001) in spheroid morphologic platelet forms in 1 hr incubations in comparison to control platelet preparations, whereas in 3 hr IL-6-platelet incubations, a 96% increase in dendritic platelet forms was observed (N = 6; P < 0.001). Significant increases in platelet ATP levels were observed in both 1 min and 1 hr high dose and low dose IL-6 platelet incubations. In 3 hr high dose-IL-6 platelet incubations, a significant 18% (N = 8; P < 0.001) decrease in platelet ATP was parallelled by a significant 40% increase (N = 8; P < 0.014) in plasma ATP in the same specimens. This increased plasma ATP was highly correlated with a reduction in platelet ATP when analyzed by bivariate regression analysis. Lastly, transmission electron microscopic analysis demonstrated a significant reduction in dense granule number and ratio of dense granule surface area/cell surface area in 3 hr high dose IL-6 incubations. These findings suggests that IL-6 activates platelets in vitro.