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Purpose: We recently reported the development of a cell-free DNA (cfDNA) targeted methylation (TM)-based sequencing approach for a multi-cancer early detection (MCED) test that includes cancer signal origin prediction. Here, we evaluated the prognostic significance of cancer detection by the MCED test using longitudinal follow-up data. Experimental Design: As part of a Circulating Cell-free Genome Atlas (CCGA) substudy, plasma cfDNA samples were sequenced using a TM approach, and machine learning classifiers predicted cancer status and cancer signal origin. Overall survival (OS) of cancer participants in the first 3 years of follow-up was evaluated in relation to cancer detection by the MCED test and clinical characteristics. Results: Cancers not detected by the MCED test had significantly better OS (P < 0.0001) than cancers detected, even after accounting for other covariates, including clinical stage and method of clinical diagnosis (i.e., standard-of-care screening or clinical presentation with signs/symptoms). Additionally, cancers not detected by the MCED test had better OS than was expected when data were adjusted for age, stage, and cancer type from the Surveillance, Epidemiology, and End Results (SEER) program. In cancers with current screening options, the MCED test also differentiated more aggressive cancers from less aggressive cancers (P < 0.0001). Conclusions: Cancer detection by the MCED test was prognostic beyond clinical stage and method of diagnosis. Cancers not detected by the MCED test had better prognosis than cancers detected and SEER-based expected survival. Cancer detection and prognosis may be linked by the underlying biological factor of tumor fraction in cfDNA.

Purpose: Signal transducer and activator of transcription 3 (Stat3) proteins have important roles in cancer cell survival and proliferation. Recent studies show that aberrant Stat3 activation promotes tumor growth and survival in several human cancers, and thus, presents an attractive pathway for the development of targeted anticancer therapy. Stat3 is a DNA-binding transcription factor, and thus, its function depends on cytoplasmic to nuclear translocation. To discover novel inhibitors of the Stat3 signaling pathway, we designed a cell-based screening assay capable of identifying compounds that inhibit Stat3 nuclear translocation and activity. Experimental Design: Cell-based fluorescence microscope screening and quantitative measurement of enhanced green fluorescent protein–Stat3 nuclear translocation assays were used to identify novel Stat3 inhibitors. The effects of identified Stat3 inhibitors on Janus kinase (Jak), Stat3 expression, and activation were determined by Western blotting and kinase in vitro autophosphorylation assay. The effects of identified Stat3 inhibitors on cell growth was evaluated by cell proliferation assay and apoptosis assay. Results: Among the National Cancer Institute Diversity set, a 2,000-member library of bioactive small molecules, we identified SD-1029 as a micromolar inhibitor of IL-6 or oncostatin-induced Stat3 nuclear translocation. Biochemical analysis shows that SD-1029 inhibits tyrosyl phosphorylation of Stat3 implicating SD-1029 as an inhibitor of Jak. Further analysis shows that this compound inhibits tyrosyl phosphorylation of the Jak2 isoenzyme. The antiapoptotic proteins Bcl-XL and survivin, target proteins of activated Stat3, are down-regulated by SD-1029 resulting in the induction of apoptosis in several human breast and ovarian cancer cell lines. SD-1029 also enhances apoptosis induced by paclitaxel in ovarian cancer cells. Conclusions: These results show that SD-1029 directly abrogates the Jak-Stat3 signaling pathway in human cancer cells expressing constitutively active Stat, and add to the growing literature that validates this pathway as a viable target for further drug development. Finally, SD-1029 may represent a suitable prototype for structural optimization and exploration as a therapeutic lead.

The spicamycin analogue KRN5500 is a nucleoside-like antibiotic with broad spectrum activity against human solid tumor models. It appears to possess a novel mechanism of action directed against the endoplasmic reticulum and Golgi apparatus with effects on protein processing. A Phase I trial was undertaken to determine the maximum tolerated dose (MTD), dose-limiting toxicities, and pharmacokinetic behavior of KRN5500 given as a 1-h i.v. infusion for 5 consecutive days every 3 weeks.Adult patients with refractory solid tumors, good performance status, and normal to near normal renal, hepatic, and hematological function were eligible for the study. At least three patients were evaluated at each dose level, and a modified Fibonacci algorithm was used for dose escalation. The MTD was based on the occurrence of severe toxicity during the first cycle of therapy. The plasma pharmacokinetics of KRN5500 was characterized during the first week of dosing.Characteristics of the 26 patients entered into the study were as follows: 13 males and 13 females; median age, 54.5 years (range, 40-70 years); and Eastern Cooperative Oncology Group performance status 0-1. A majority had refractory colorectal carcinoma (17 of 26 patients) with at least two prior regimens of therapy. The dose of KRN5500 was escalated from 0.8 to 4.9 mg/m(2)/day in five dose levels, and the MTD was 2.9 mg/m(2)/day. All dose-limiting toxicities were nonhematological and included pulmonary toxicities, hyperglycemia, fatigue, hepatotoxicity, and ataxia, with one fatality due to interstitial pneumonitis. Clinically significant toxicities occurring in multiple patients that were not dose-limiting included nausea/vomiting, diarrhea, fatigue, neurological symptoms, hyperbilirubinemia, hyperglycemia, lymphopenia, and thrombocytopenia. There were no objective responses, although 3 of 17 evaluable patients exhibited disease stabilization for 5-6 cycles. The pharmacokinetics for the first dose of KRN5500 was biexponential and linear across all five dose levels. Mean values of pharmacokinetic parameters were as follows: total plasma clearance, 6.15 +/- 2.37 liters/h/m(2); apparent volume of distribution at steady state, 6.56 +/- 1.98 liters/m(2); biological half-life, 1.29 +/- 0.37 h; and mean residence time, 1.07 +/- 0.31 h. Clearance was significantly lower (P = 0.011) in the eight patients who were at least 65 years old (4.6 +/- 1.6 liters/h/m(2)) as compared with the 18 younger patients (7.1 +/- 2.3 liters/h/m(2)). Peak plasma concentrations of KRN5500 in the cohort receiving the MTD ranged from 350 to 400 ng/ml.The MTD of KRN5500, when given as a 1-h i.v. infusion for 5 consecutive days, was 2.9 mg/m(2)/day. The only suggestion of therapeutic activity observed in this study was disease stabilization in three patients with chemorefractory colorectal cancer. Administering KRN5500 as a continuous i.v. infusion with the objective of prolonging systemic exposure to potentially cytotoxic concentrations of the drug should be considered.

Previous studies directed at identifying paclitaxel resistance genes in a paclitaxel-resistant subclone of the human ovarian cancer cell line SKOV-3 identified a novel cancer testis antigen, Taxol resistance-associated gene 3 (TRAG-3). Because investigation suggested that TRAG-3, located on chromosome Xq28, does not directly participate in the paclitaxel-resistant phenotype, it was hypothesized that TRAG-3 might be linked to a neighboring gene that is directly involved in the drug-resistant phenotype, or alternatively, overexpression of TRAG-3 might be attributable to coregulation with other cancer testis antigens. To distinguish between these two hypotheses, expression of the genes that flank TRAG-3 was evaluated, namely the Centrin 2 gene and several members of the MAGE gene cluster. Northern analysis demonstrates overexpression of MAGE2 but not Centrin 2. Extension of this analysis to other neighboring and non-neighboring representative cancer testis antigens reveals overexpression of MAGE3, MAGE6, MAGE11, and MAGE12, as well as GAGE-2, GAGE-4, GAGE-5, GAGE-6, and GAGE-7 (clustered on Xp11) in SKOV-3(TR), as compared with SKOV-3. In addition, Affymetrix-based analysis of gene expression in SKOV-3 subclones with variable paclitaxel resistance demonstrates MAGE gene overexpression occurs early in the development of the paclitaxel-resistant phenotype, whereas GAGE gene overexpression occurs somewhat later. Evaluation of additional breast and ovarian cancer cell lines reveals MAGE/GAGE overexpression in both paclitaxel- and doxorubicin-resistant cell lines, whereas gemcitabine-resistant subclones of several ovarian cancer cell lines, including SKOV-3(GR), reveals no change in MAGE/GAGE expression. To determine whether MAGE gene overexpression contributes directly to the drug-resistant phenotype, MAGE2 or MAGE6, cDNA was introduced into the paclitaxel-sensitive human ovarian cancer cell line OVCAR8. 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide cytotoxicity analysis of both MAGE2 and MAGE6 transfectants demonstrates a 4-fold increase in resistance to paclitaxel and 2-fold increase in resistance to doxorubicin but not to other drugs, such as topotecan and cisplatin, through a nonmultidrug resistance-1 mechanism. MAGE2 or MAGE6 overexpression also induces a growth advantage in OVCAR8-transfected cells. These studies suggest that the in vitro acquisition of paclitaxel and doxorubicin resistance can be associated with increased expression of a variety of both neighboring and non-neighboring cancer testis antigens genes. This does not appear to be a consequence of random genetic instability or genomic amplification of the X chromosome. These antigens, because of limited expression in normal tissues, may be suitable targets for immunotherapy and novel therapeutic strategies in the treatment of chemotherapy-resistant epithelial tumors.

To determine whether agents that target topoisomerase I and II could be administered sequentially.A Phase I study was conducted to evaluate sequential treatment with bolus IV doxorubicin followed 48 h later by topotecan given as a 30-min i.v. infusion on 3 consecutive days, with additional cycles of therapy repeated every 3 weeks. Characteristics of the 22 patients entered into the study were: 13 male and 9 female; median age, 49.5 (range 33-66) years; Eastern Cooperative Oncology Group performance status, 0-1; and normal cardiac, hematological, hepatic, and renal function. All patients had received prior therapy (medianor=2 prior regimens).The maximum tolerated dose of the combination was 25 mg/m(2) doxorubicin and 5.25 mg/m(2) topotecan (1.75 mg/m(2)/day x 3). Neutropenia was the dose-limiting toxicity. Attempts to further escalate the dose using 5 microg/kg granulocyte colony-stimulating factor proved unsuccessful because of thrombocytopenia. Among the 17 patients who were evaluable for response, 6 had a partial response, and 4 showed evidence of disease stabilization. The partial responses occurred in patients with small cell lung cancer (3 of 7), non-small cell lung cancer (1 of 6), esophageal adenocarcinoma (1 of 2), and ovarian carcinoma (1 of 1), and it lasted for 3-6 months. Administration of doxorubicin 2 days before topotecan did not alter topotecan pharmacokinetics. Changes in topoisomerase mRNA levels were observed during chemotherapy.The sequential combination of doxorubicin followed by topotecan is highly active in several chemotherapy refractory long, ovary, and esophageal cancers. Despite significant neutropenia, toxicity is manageable and well tolerated. Phase II trials to further evaluate the efficacy of this promising combination regimen against non-Hodgkin's lymphoma and lung cancer have been initiated.