Single-cell analysis of circulating tumor cells identifies cumulative expression patterns of EMT-related genes in metastatic prostate cancer.

BACKGROUND: Prostate tumors shed circulating tumor cells (CTCs) into the blood stream. Increased evidence shows that CTCs are often present in metastatic prostate cancer and can be alternative sources for disease profiling and prognostication. Here we postulate that CTCs expressing genes related to epithelial-mesenchymal transition (EMT) are strong predictors of metastatic prostate cancer. METHODS: A microfiltration system was used to trap CTCs from peripheral blood based on size selection of large epithelial-like cells without CD45 leukocyte marker. These cells individually retrieved with a micromanipulator device were assessed for cell membrane physical properties using atomic force microscopy. Additionally, 38 CTCs from eight prostate cancer patients were used to determine expression profiles of 84 EMT-related and reference genes using a microfluidics-based PCR system. RESULTS: Increased cell elasticity and membrane smoothness were found in CTCs compared to noncancerous cells, highlighting their potential invasiveness and mobility in the peripheral circulation. Despite heterogeneous expression patterns of individual CTCs, genes that promote mesenchymal transitioning into a more malignant state, including IGF1, IGF2, EGFR, FOXP3, and TGFB3, were commonly observed in these cells. An additional subset of EMT-related genes (e.g., PTPRN2, ALDH1, ESR2, and WNT5A) were expressed in CTCs of castration-resistant cancer, but less frequently in castration-sensitive cancer. CONCLUSIONS: The study suggests that an incremental expression of EMT-related genes in CTCs is associated with metastatic castration-resistant cancer. Although CTCs represent a group of highly heterogeneous cells, their unique EMT-related gene signatures provide a new opportunity for personalized treatments with targeted inhibitors in advanced prostate cancer patients.

Promoting Factors and Barriers to Participation in Early Phase Clinical Trials: Patients Perspectives.

BACKGROUND: Inclusion of minorities in clinical research is an essential step to develop novel cancer treatments, improve health care overall, understand potential differences in pharmacogenomics and address minorities' disproportionate cancer burden. However, Latinos and other minority groups continue to be critically underrepresented, particularly in early-phase clinical trials (EPCTs). The objective of the present study was to explore barriers and promoting factors influencing patients' decisions to enroll or not in early phase clinical trials (EPCTs) and identify areas for intervention to increase minority enrollment into clinical research. METHODS: An interviewer-administered survey was conducted with 100 cancer patients in the predominantly Latino region of South Texas. Exploratory factor analysis was conducted to identify underlying dimensions, and multiple logistic regression assessed significant factors that promote or deter patients enrollment to EPCTs. In addition, a separate subgroup mean analysis assessed differences by enrollment status and race/ethnicity. RESULTS: For one standard deviation increase in the importance given to the possibility of symptoms improvement, the predicted odds of refusing enrollment were 3.20 times greater (OR=3.20, 95% CI=1.06-9.71, p 0.040). Regarding barriers, among patients who considered fear/uncertainty of the new treatment a deterrent to enrollment, one standard deviation increase in agreement with these barriers was associated with a 3.60 increase (OR=3.60, 95% CI=1.30-9.97h, p 0.014) in the odds of not being enrolled in an EPCT. In contrast, non-enrolled patients were less likely (OR=0.14, 95% CI=0.05-0.44, p 0.001) to consider fatalistic beliefs as an important barrier. CONCLUSION: This study, one of the first to identify South Texas patients' barriers to enroll in EPCTs, highlights potential focal areas to increase participation of both minority and non-minority patients in clinical research. Culturally tailored interventions promoting patient-centered care and bilingual, culturally competent study teams could solve common barriers and enhance Latinos' likelihood of joining clinical trials. These interventions may simultaneously increase opportunities to involve patients and physicians in clinical trials, while ensuring the benefits of participation are equitably distributed to all patients.

Early Phase Clinical Trials: Referral Barriers and Promoters among Physicians.

BACKGROUND: Physician referral is among the most effective means of recruiting patients into cancer clinical trials. Therefore, to increase minority representation in early-phase clinical trials (EPCTs), specifically accrual of Latinos, it is first necessary to examine physicians' attitudes and practices regarding these studies and factors that influence physicians' referral decisions. METHODS: This study surveyed oncologists (N=111) from a Texas Medical Association mailing list to examine barriers and promoting factors associated with physician referral of patients to EPCTs and identify areas for intervention to increase accrual of Latinos and other minorities into clinical research. Exploratory factor analysis was conducted to identify underlying dimensions, and significant factors that promote or deter physicians from referring patients to EPCTs were assessed through multiple logistic regression. RESULTS: Burden of the clinical trial process was the only significant dimension associated with referring patients to EPCTs. Physicians who agreed with this set of logistical barriers-such as diverting time and resources away from their practice-were less likely to refer patients than physicians with opposing opinions (OR= 0.28, 95% CI= 0.08-0.94). CONCLUSION: This study, one of the first to identify physician barriers for referring patients to EPCTs in Texas, highlights potential focal areas for physician and community-based education and communication to promote clinical trial opportunities among both minority and non-minority patients. Given that Texas physicians deal with a large proportion of Latino patients, such efforts could also address ethnic disparities in clinical trial participation, which will become increasingly important as the Latino population continues to grow.

Direct Raman imaging techniques for study of the subcellular distribution of a drug.

Direct Raman imaging techniques are demonstrated to study the drug distribution in living cells. The advantage of Raman imaging is that no external markers are required, which simplifies the sample preparation and minimally disturbs the drug mechanism during imaging. The major challenge in Raman imaging is the weak Raman signal. In this study, we present a Raman image model to describe the degradation of Raman signals by imaging processes. Using this model, we demonstrate special-purpose image-processing algorithms to restore the Raman images. The processing techniques are then applied to visualize the anticancer agent paclitaxel in living MDA-435 breast cancer cells. Raman images were obtained from a cancer cell before, during, and after drug treatment. The paclitaxel distribution illustrated in these images is explained by means of the binding characteristics of the paclitaxel and its molecular target-the microtubules. This result demonstrates that direct Raman imaging is a promising tool to study the distribution of a drug in living cells.

Anemia and hepatosplenomegaly as presenting features in a child with rickets and secondary myelofibrosis.

Anemia and hepatosplenomegaly are common reasons for referring a child to a pediatric hematologist or oncologist. Among the many causes for these findings is severe rickets, which has been shown to be associated with secondary myelofibrosis and myeloid metaplasia. The authors present the case of an infant with severe rickets and secondary myelofibrosis and review the differential diagnosis of hepatosplenomegaly from the viewpoint of the pediatric hematologist/oncologist.

Phase I trial of rebeccamycin analog (NSC #655649) in children with refractory solid tumors: a pediatric oncology group study.

PURPOSE: To conduct a phase 1 trial of rebeccamycin analog (NSC #655649) in children with solid tumors to establish the dose-limiting toxicity (DLT) and maximum-tolerated dose (MTD); to establish the pharmacokinetic profile in children, and to document any evidence of antitumor activity. METHODS: A 1-hour infusion of NSC #655649 was administered every 21 days to 17 patients younger than 21 years who had malignant tumors refractory to conventional therapy. Doses ranged from 450 mg/m2 to 760 mg/m2. Pharmacokinetics were done in at least three patients per dose level. The first course was used to determine DLT and MTD. RESULTS: Sixteen patients on three dose levels were assessable for toxicities. At 760 mg/m2, four patients had dose-limiting neutropenia and thrombocytopenia. Pharmacokinetics were assessable in 13 patients. Plasma concentrations declined triexponentially and concentrations above the range of in vitro antitumor activity were maintained for 3 days. Analysis of urine extracts revealed the presence of an N-de-ethylated metabolite and probable involvement of cytochrome P450 isoenzyme(s) in the metabolism of NSC #655649. Pharmacodynamic studies showed a relationship between the area under the curve and percentage change in absolute neutrophil count in the E(max) model (r2 = 0.56, P = 0.001). CONCLUSIONS: The recommended phase 2 dose of NSC #655649 administered as a 1-hour infusion every 21 days to children with solid tumors is 585 mg/m2. Both neutropenia and thrombocytopenia were found to be dose-limiting toxicities.

Preclinical antitumor activity and pharmacokinetics of methyl-2-benzimidazolecarbamate (FB642).

Methyl-2-benzimidazolecarbamate (carbendazim, FB642) is an anticancer agent that induces apoptosis of cancer cells. In vitro, FB642 demonstrated potent antitumor activity against both the murine B16 melanoma (IC50 = 8.5 microm) and human HT-29 colon carcinoma (IC50 = 9.5 microm) cell lines. FB642 was also highly active against both murine tumor models and human tumor xenografts at varying doses and schedules. In the murine B16 melanoma model, T/C values > 200 were observed. In the human tumor xenograft, FB642 produced tumor growth inhibition of greater than 58% in five of the seven xenograft models evaluated. Partial and complete tumor shrinkage was noted with FB642 against the MCF-7 breast tumor model. Pharmacokinetic studies in rats demonstrated that oral absorption of FB642 was variable and may be saturated at the 2000 mg/kg dose level since higher doses failed to produce a further increase in the area under the time concentration curve. Toxicity of FB642 in vivo appeared to be dose-dependent. Lower doses in the range of 2,000-3,000 mg/kg were better tolerated, while still preserving antitumor activity. Evaluation of FB642 in phase I clinical trials of adult patients with advanced malignancies is currently ongoing.