Use of baculovirus BacMam vectors for expression of ABC drug transporters in mammalian cells.

ATP-binding cassette (ABC) drug transporters ABCB1 [P-glycoprotein (Pgp)] and ABCG2 are expressed in many tissues including those of the intestines, the liver, the kidney and the brain and are known to influence the pharmacokinetics and toxicity of therapeutic drugs. In vitro studies involving their functional characteristics provide important information that allows improvements in drug delivery or drug design. In this study, we report use of the BacMam (baculovirus-based expression in mammalian cells) expression system to express and characterize the function of Pgp and ABCG2 in mammalian cell lines. BacMam-Pgp and BacMam-ABCG2 baculovirus-transduced cell lines showed similar cell surface expression (as detected by monoclonal antibodies with an external epitope) and transport function of these transporters compared to drug-resistant cell lines that overexpress the two transporters. Transient expression of Pgp was maintained in HeLa cells for up to 72 h after transduction (48 h after removal of the BacMam virus). These BacMam-baculovirus-transduced mammalian cells expressing Pgp or ABCG2 were used for assessing the functional activity of these transporters. Crude membranes isolated from these cells were further used to study the activity of these transporters by biochemical techniques such as photo-cross-linking with transport substrate and adenosine triphosphatase assays. In addition, we show that the BacMam expression system can be exploited to coexpress both Pgp and ABCG2 in mammalian cells to determine their contribution to the transport of a common anticancer drug substrate. Collectively, these data demonstrate that the BacMam-baculovirus-based expression system can be used to simultaneously study the transport function and biochemical properties of ABC transporters.

Chemotherapy Knowledge Base Management in the Era of Precision Oncology.

Cancer medicine has grown increasingly complex in recent years with the advent of precision oncology and wide utilization of multidrug regimens. Representing this increasingly granular knowledge is a significant challenge. As users and managers of a freely available chemotherapy drug and regimen database, we describe the changes we have made to accommodate these challenges. These include the development of a domain ontology and increased granularity in the classification of cancer types on the website.

Association of Population Screening for Breast Cancer Risk With Use of Mammography Among Women in Medically Underserved Racial and Ethnic Minority Groups.

Importance: Black women bear a disproportionate burden of breast cancer mortality in the US, in part due to inequities in the use of mammography. Population screening for breast cancer risk in primary care is a promising strategy for mitigating breast cancer disparities, but it is unknown whether this strategy would be associated with increased mammography rates in underserved women of racial and ethnic minority groups. Objective: To examine whether providing individualized breast cancer risk estimates is associated with an increase in the rate of screening mammography. Design, Setting, and Participants: A cohort study was conducted in women receiving individualized risk estimates as part of routine primary health care at federally qualified health centers in medically underserved communities in Chicago, Illinois. The study was conducted from November 5, 2013, to December 19, 2014, with data acquisition completed on March 5, 2017; data analysis was performed from December 30, 2020, to February 2, 2021. A total of 347 women aged 25 to 69 years without a personal history of breast cancer presenting for an annual visit with their primary care clinician were enrolled. Exposures: Breast cancer risk estimates were obtained with validated risk assessment tools as a standard component of the clinic check-in process. One of 4 women at average risk and all women at high risk were invited to participate in the study. Main Outcomes and Measures: The primary outcome was the mammography rate during 18 months of usual care compared with the rate during 18 months after implementation of risk assessment. Results: Of the 347 women enrolled, 188 were age-eligible for mammography and were included in the analysis (mean [SD] age, 50.8 [7.04] years); 70 women (37.2%) were Hispanic, 114 (60.6%) were non-Hispanic African American, and 4 (2.1%) were from other racial and ethnic groups (4 non-Hispanic White women). Ninety-eight women (52.1%) had an average risk of developing breast cancer and 90 (47.9%) were at high risk. Overall, there was a nonsignificant increase in the mammography rate, from 38.8% during usual care to 48.9% following implementation of risk assessment (odds ratio, 1.37; 95% CI, 0.92-2.03). In preplanned subgroup analysis, the mammography rate among women at high risk was significantly higher after vs before risk assessment (51.1% vs 36.6%; odds ratio, 1.88; 95% CI, 1.10-3.23). Conclusions and Relevance: In this study, providing individualized breast cancer risk estimates as a component of primary health care in federally qualified health centers was associated with increased use of mammography among women of racial and ethnic minority groups who were at high risk. Implementation of this approach in underserved communities could promote equity in the use of mammography and reduce racial disparities in breast cancer mortality. This strategy warrants further investigation.

Seven decades of chemotherapy clinical trials: a pan-cancer social network analysis.

Clinical trials establish the standard of cancer care, yet the evolution and characteristics of the social dynamics between the people conducting this work remain understudied. We performed a social network analysis of authors publishing chemotherapy-based prospective trials from 1946 to 2018 to understand how social influences, including the role of gender, have influenced the growth and development of this network, which has expanded exponentially from fewer than 50 authors in 1946 to 29,197 in 2018. While 99.4% of authors were directly or indirectly connected by 2018, our results indicate a tendency to predominantly connect with others in the same or similar fields, as well as an increasing disparity in author impact and number of connections. Scale-free effects were evident, with small numbers of individuals having disproportionate impact. Women were under-represented and likelier to have lower impact, shorter productive periods (P < 0.001 for both comparisons), less centrality, and a greater proportion of co-authors in their same subspecialty. The past 30 years were characterized by a trend towards increased authorship by women, with new author parity anticipated in 2032. The network of cancer clinical trialists is best characterized as strategic or mixed-motive, with cooperative and competitive elements influencing its appearance. Network effects such as low centrality, which may limit access to high-profile individuals, likely contribute to the observed disparities.

Expression of Aurora A (but not Aurora B) is predictive of survival in breast cancer.

PURPOSE: The cell cycle mediators Aurora A and B are targets of drugs currently in clinical development. As with other targeted therapies in breast cancer, response to therapy might be associated with target expression in tumors. We therefore assessed expression of Aurora A and B in breast tumors and studied associations with clinical/pathologic variables. EXPERIMENTAL DESIGN: Tissue microarrays containing primary specimens from 638 patients with 15-year follow-up were employed to assess expression of Aurora A and B using our automated quantitative analysis method; we used cytokeratin to define pixels as breast cancer (tumor mask) within the array spot and measured Aurora A and B expression within the mask using Cy5-conjugated antibodies. RESULTS: Aurora A and B expression was variable in primary breast tumors. High Aurora A expression was strongly associated with decreased survival (P = 0.0005). On multivariable analysis, it remained an independent prognostic marker. High Aurora A expression was associated with high nuclear grade and high HER-2/neu and progesterone receptor expression. Aurora B expression was not associated with survival. CONCLUSIONS: Aurora A expression defines a population of patients with decreased survival, whereas Aurora B expression does not, suggesting that Aurora A might be the preferred drug target in breast cancer. Aurora A expression in early-stage breast cancer may identify a subset of patients requiring more aggressive or pathway-targeted treatment. Prospective studies are needed to confirm the prognostic role of Aurora A as well as the predictive role of Aurora A expression in patients treated with Aurora A inhibitors.

The relationship between ehrlichiosis and the development of hematologic malignancies.

Viral and bacterial infections cause chronic inflammation and produce bacterial metabolites that may lead to carcinogenesis. Ehrlichiosis is an intracellular infection that primarily infects white blood cells. Given that infections can lead to cancer, and that Ehrlichia has tropism for white blood cells, it can be deduced that Ehrlichia may cause hematologic malignancies, such as acute leukemia. A prospective study was performed that tested the blood of ten patients with acute leukemia for prior exposure to Ehrlichia. The RT-PCR that was performed did not detect Ehrlichia DNA in any of the ten samples. Therefore, based on this small study, one cannot conclude that Ehrlichia can lead to hematologic malignancies.