Lack of racial and ethnic diversity in lung cancer cell lines contributes to lung cancer health disparities.

Lung cancer is the leading cause of cancer death in the United States and worldwide, and a major source of cancer health disparities. Lung cancer cell lines provide key in vitro models for molecular studies of lung cancer development and progression, and for pre-clinical drug testing. To ensure health equity, it is imperative that cell lines representing different lung cancer histological types, carrying different cancer driver genes, and representing different genders, races, and ethnicities should be available. This is particularly relevant for cell lines from Black men, who experience the highest lung cancer mortality in the United States. Here, we undertook a review of the available lung cancer cell lines and their racial and ethnic origin. We noted a marked imbalance in the availability of cell lines from different races and ethnicities. Cell lines from Black patients were strongly underrepresented, and we identified no cell lines from Hispanic/Latin(x) (H/L), American Indian/American Native (AI/AN), or Native Hawaiian or other Pacific Islander (NHOPI) patients. The majority of cell lines were derived from White and Asian patients. Also missing are cell lines representing the cells-of-origin of the major lung cancer histological types, which can be used to model lung cancer development and to study the effects of environmental exposures on lung tissues. To our knowledge, the few available immortalized alveolar epithelial cell lines are all derived from White subjects, and the race and ethnicity of a handful of cell lines derived from bronchial epithelial cells are unknown. The lack of an appropriately diverse collection of lung cancer cell lines and lung cancer cell-of-origin lines severely limits racially and ethnically inclusive lung cancer research. It impedes the ability to develop inclusive models, screen comprehensively for effective compounds, pre-clinically test new drugs, and optimize precision medicine. It thereby hinders the development of therapies that can increase the survival of minority and underserved patients. The noted lack of cell lines from underrepresented groups should constitute a call to action to establish additional cell lines and ensure adequate representation of all population groups in this critical pre-clinical research resource.

Factors leading to disparity in lung cancer diagnosis among black/African American communities in the USA: a qualitative study.

OBJECTIVE: This study has two objectives: first, to explore the diagnostic experiences of black/African American (BAA) patients with lung cancer to pinpoint pitfalls, suboptimal experiences and instances of discrimination leading to disparities in outcomes compared with patients of other ethnic backgrounds, especially white patients. The second objective is to identify the underlying causes contributing to health disparities in the diagnosis of lung cancer among BAA patients. METHODS: We employed a phenomenological research approach, guiding in-depth interviews with patients self-identifying as BAA diagnosed with lung cancer, as well as caregivers, healthcare professionals and community advocates knowledgeable about BAA experiences with lung cancer. We performed thematic analysis to identify experiences at patient, primary care and specialist levels. Contributing factors were identified using the National Institute of Minority Health and Health Disparities (NIMHD) health disparity model. RESULTS: From March to November 2021, we conducted individual interviews with 19 participants, including 9 patients/caregivers and 10 providers/advocates. Participants reported recurring and increased pain before seeking treatment, treatment for non-cancer illnesses, delays in diagnostic tests and referrals, poor communication and bias when dealing with specialists and primary care providers. Factors contributing to suboptimal experiences included reluctance by insurers to cover costs, provider unwillingness to conduct comprehensive testing, provider bias in recommending treatment, high healthcare costs, and lack of healthcare facilities and qualified staff to provide necessary support. However, some participants reported positive experiences due to their insurance, availability of services and having an empowered support structure. CONCLUSIONS: BAA patients and caregivers encountered suboptimal experiences during their care. The NIMHD model is a useful framework to organise factors contributing to these experiences that may be leading to health disparities. Additional research is needed to fully capture the extent of these experiences and identify ways to improve BAA patient experiences in the lung cancer diagnosis pathway.

A qualitative study of interactions with oncologists among patients with advanced lung cancer.

INTRODUCTION: To support the care of lung cancer patients, oncologists have needed to stay current on treatment advancements and build relationships with a new group of survivors in an era where lung cancer survivorship has been re-defined. The objectives of the study were to (1) understand the perspectives of advanced lung cancer patients whose tumors have oncogenic alterations about their care experiences with their oncologist(s) and (2) describe the perceptions of advanced lung cancer patients about seeking second opinions and navigating care decisions. METHODS: In this qualitative study, patients with advanced lung cancer (n = 25) on targeted therapies were interviewed to discuss their ongoing experience with their oncologists. We used deductive and inductive qualitative approaches in the coding of the data. We organized the data using the self-determination framework. RESULTS: Patients described both positive and negative aspects of their care as related to autonomy, provider competency, and connectedness. Patients sought second opinions for three primary reasons: expertise, authoritative advice, and access to clinical trial opportunities. When there is disagreement in the treatment plan between the primary oncologist and the specialist, there can be confusion and tension, and patients have to make difficult choices about their path forward. CONCLUSIONS: Patients value interactions that support their autonomy, demonstrate the competency of their providers, and foster connectedness. To ensure that patients receive quality and goal-concordant care, developing decision aids and education materials that help patients negotiate recommendations from two providers is an area that deserves further attention.

TSP1 and TSP2 deficiencies affect LOX protein distribution in the femoral diaphysis and pro-peptide removal in marrow-derived mesenchymal stem cells in vitro.

Thrombospondin-1 and 2 have each been implicated in collagen fibrillogenesis. We addressed the possibility that deficits in lysyl oxidase (LOX) contribute to the extracellular matrix (ECM) phenotype of TSP-deficient bone. We examined detergent insoluble (mature cross-linked) and soluble (newly secreted) ECM fractions prepared from diaphyseal cortical bone. Detergent-insoluble hydroxyproline content, an indicator of cross-linked collagen content and LOX function, was reduced in female TSP-deficient bones. In male diaphyses, only TSP2 deficiency affected insoluble hydroxyproline content. Western blot suggested that removal of the LOX-pro-peptide (LOPP), an indication of LOX activation, was not affected by TSP status. Instead, the distribution of pro-LOX and mature LOX between immature and mature ECM was altered by TSP-status. LOX was also examined in primary marrow-derived mesenchymal stem cells (MSC) treated with ascorbate. Relative LOPP levels were elevated compared to WT in MSC conditioned medium from female TSP-deficient mice. When cells were serum starved to limit LOX pro-peptide removal, pro-LOX levels were elevated in TSP2-/- cells compared to wild-type. This phenotype was associated with a transient increase in BMP1 levels in TSP2-/- conditioned medium. TSP2 was detected in bone tissue and osteoblast cell culture. TSP1 was only detected in insoluble ECM prepared from WT diaphyseal bone samples. Our data suggest that the trimeric thrombospondins contribute to bone matrix quality by regulating the distribution of pro and mature LOX between newly secreted, immature ECM and mature, cross-linked ECM.

Canalization Leads to Similar Whole Bone Mechanical Function at Maturity in Two Inbred Strains of Mice.

Previously, we showed that cortical mineralization is coordinately adjusted to mechanically offset external bone size differences between A/J (narrow) and C57BL/6J (wide) mouse femora to achieve whole bone strength equivalence at adulthood. The identity of the genes and their interactions that are responsible for establishing this homeostatic state (ie, canalization) remain unknown. We hypothesize that these inbred strains, whose interindividual differences in bone structure and material properties mimic that observed among humans, achieve functional homeostasis by differentially adjusting key molecular pathways regulating external bone size and mineralization throughout growth. The cortices of A/J and C57BL/6J male mouse femora were phenotyped and gene expression levels were assessed across growth (ie, ages 2, 4, 6, 8, 12, 16 weeks). A difference in total cross-sectional area (p < 0.01) and cortical tissue mineral density were apparent between mouse strains by age 2 weeks and maintained at adulthood (p < 0.01). These phenotypic dissimilarities corresponded to gene expression level differences among key regulatory pathways throughout growth. A/J mice had a 1.55- to 7.65-fold greater expression among genes inhibitory to Wnt pathway induction, whereas genes involved in cortical mineralization were largely upregulated 1.50- to 3.77-fold to compensate for their narrow diaphysis. Additionally, both mouse strains showed an upregulation among Wnt pathway antagonists corresponding to the onset of adult ambulation (ie, increased physiological loads). This contrasts with other studies showing an increase in Wnt pathway activation after functionally isolated, experimental in vivo loading regimens. A/J and C57BL/6J long bones provide a model to develop a systems-based approach to identify individual genes and the gene-gene interactions that contribute to trait differences between the strains while being involved in the process by which these traits are coordinately adjusted to establish similar levels of mechanical function, thus providing insight into the process of canalization. © 2017 American Society for Bone and Mineral Research.

Thrombospondin-2 deficiency in growing mice alters bone collagen ultrastructure and leads to a brittle bone phenotype.

Thrombospondin-2 (TSP2) is a matricellular protein component of the bone extracellular matrix. Long bones of adult TSP2-deficient mice have increased endosteal bone thickness due to expansion of the osteoblast progenitor cell pool, and these cells display deficits in osteoblastic potential. Here, we investigated the effects of TSP2 deficiency on whole bone geometric and mechanical properties in growing 6-wk-old male and female wild-type and TSP2-knockout (KO) mice. Microcomputed tomography and mechanical testing were conducted on femora and L2 vertebrae to assess morphology and whole bone mechanical properties. In a second series of experiments, femoral diaphyses were harvested from wild-type and TSP2-KO mice. Detergent-soluble type I collagen content was determined by Western blot of right femora. Total collagen content was determined by hydroxyproline analysis of left femora. In a third series of experiments, cortical bone was dissected from the anterior and posterior aspects of the femoral middiaphysis and imaged by transmission electron microscopy to visualize collagen fibrils. Microcomputed tomography revealed minimal structural effects of TSP2 deficiency. TSP2 deficiency imparted a brittle phenotype on cortical bone. Femoral tissue mineral density was not affected by TSP2 deficiency. Instead, transmission electron microscopy revealed less intensely stained collagen fibrils with altered morphology in the extracellular matrix assembled by osteoblasts on the anterior surface of TSP2-KO femora. Femoral diaphyseal bone displayed comparable amounts of total collagen, but the TSP2-KO bones had higher levels of detergent-extractable type I collagen. Together, our data suggest that TSP2 is required for optimal collagen fibrillogenesis in bone and thereby contributes to normal skeletal tissue quality.

H460 non-small cell lung cancer stem-like holoclones yield tumors with increased vascularity.

Cancer stem-like cells were isolated from several human tumor cell lines by limiting dilution assays and holoclone morphology, followed by assessment of self-renewal capacity, tumor growth, vascularity, and blood perfusion. H460 holoclone-derived tumors grew slower than parental H460 tumors, but displayed significantly increased microvessel density and tumor blood perfusion. Microarray analysis identified 177 differentially regulated genes in the holoclone-derived tumors, of which 47 were associated with angiogenesis. The dysregulated genes include several small leucine-rich proteoglycans that may modulate angiogenesis and serve as novel therapeutic targets for inhibiting cancer stem cell-driven angiogenesis.

Impact of tumor blood flow modulation on tumor sensitivity to the bioreductive drug banoxantrone.

We investigated the hypoxia-dependent cytotoxicity of AQ4N (banoxantrone) using a panel of 13 cancer cell lines and studied its relationship to the expression of the quinone reductase DT-diaphorase (NQO1), which is widely found in cancer cells. We also investigated pharmacologic treatments that increase tumor hypoxia in vivo and their impact on AQ4N chemosensitivity in a solid tumor xenograft model. AQ4N showed ≥ 8-fold higher cytotoxicity under hypoxia than normoxia in cultures of 9L rat gliosarcoma and H460 human non-small-cell lung carcinoma cells but not for 11 other human cancer cell lines. DT-diaphorase protein levels and AQ4N chemosensitivity were poorly correlated across the cancer cell line panel, and AQ4N chemosensitivity was not affected by DT-diaphorase inhibitors. The vasodilator hydralazine decreased tumor perfusion and increased tumor hypoxia in 9L tumor xenografts, and to a lesser extent in H460 tumor xenografts. However, hydralazine did not increase AQ4N-dependent antitumor activity. Combination of AQ4N with the angiogenesis inhibitor axitinib, which increases 9L tumor hypoxia, transiently increased antitumor activity but with an increase in host toxicity. These findings indicate that the capacity to bioactivate AQ4N is not dependent on DT-diaphorase and is not widespread in cultured cancer cell lines. Moreover, the activation of AQ4N cytotoxicity in vivo requires tumor hypoxia that is more extensive or prolonged than can readily be achieved by vasodilation or by antiangiogenic drug treatment.

Required test duration for group comparisons in ligament viscoelasticity: a statistical approach.

The goal of this study was to determine the duration of time that ligaments from a study group need to be loaded in order to adequately determine their collective viscoelastic behavior. Rat ligaments were subjected either to creep or stress relaxation for 1,000 s or stress relaxation for 10,000 s to compare estimates of viscoelastic behavior for different test durations. Stresses versus time (relaxation) or strains versus time (creep) were fit with power law models (tbeta where beta is the rate of creep or relaxation on a log-log scale). Time intervals were separated by logarithmic decade and analyzed using a Random Coefficients approach to compute residual specimen error as a function of the number of decades of data analyzed. Standard Regression was also used for comparison. Results show that by testing for