Gene expression predicts dormant metastatic breast cancer cell phenotype

BACKGROUND

Breast cancer can recur months to decades after an initial diagnosis and treatment. The mechanisms that control tumor cell dormancy remain poorly understood, making it difficult to predict which patients will recur and thus benefit from more rigorous screening and treatments. Unfortunately, the extreme rarity of dormant DTCs has been a major obstacle to their study.

METHODS

To overcome this challenge, we developed an efficient system to isolate and study rare dormant breast cancer cells from metastatic organs including bones, which represent a major site of metastasis. After isolation of cells from the long bones, we used single cell RNA-sequencing (scRNA-seq) to profile proliferative and dormant PyMT-Bo1 breast cancer cells. We also compared this signature to dormant versus proliferative tumor cells isolated from the lungs. Finally, we compared our dormant signature to human datasets.

RESULTS

We identified a group of genes including Cfh, Gas6, Mme and Ogn that were highly expressed in dormant breast cancer cells present in the bone and lung. Expression of these genes had no impact on dormancy in murine models, but their expression correlated with disease-free survival in primary human breast cancer tumors, suggesting that these genes have predictive value in determining which patients are likely to recur.

CONCLUSIONS

Dormant breast cancer cells exhibit a distinct gene expression signature regardless of metastatic site. Genes enriched in dormant breast cancer cells correlate with recurrence-free survival in breast cancer patients.

Osteocyte transcriptome mapping identifies a molecular landscape controlling skeletal homeostasis and susceptibility to skeletal disease

Osteocytes are master regulators of the skeleton. We mapped the transcriptome of osteocytes from different skeletal sites, across age and sexes in mice to reveal genes and molecular programs that control this complex cellular-network. We define an osteocyte transcriptome signature of 1239 genes that distinguishes osteocytes from other cells. 77% have no previously known role in the skeleton and are enriched for genes regulating neuronal network formation, suggesting this programme is important in osteocyte communication. We evaluated 19 skeletal parameters in 733 knockout mouse lines and reveal 26 osteocyte transcriptome signature genes that control bone structure and function. We showed osteocyte transcriptome signature genes are enriched for human orthologs that cause monogenic skeletal disorders (P = 2.4 × 10-22) and are associated with the polygenic diseases osteoporosis (P = 1.8 × 10-13) and osteoarthritis (P = 1.6 × 10-7). Thus, we reveal the molecular landscape that regulates osteocyte network formation and function and establish the importance of osteocytes in human skeletal disease.

Lack of effect of Lactobacillus GG on antibiotic-associated diarrhea: a randomized, placebo-controlled trial

OBJECTIVES

To assess the efficacy of Lactobacillus GG in preventing antibiotic-associated diarrhea (AAD) in adults and, secondarily, to assess the effect of coadministered Lactobacillus GG on the number of tests performed to determine the cause of diarrhea.

PATIENTS AND METHODS

In this prospective, randomized, double-blind, placebo-controlled trial conducted from July 1998 to October 1999, 302 hospitalized patients receiving antibiotics were randomized to receive Lactobacillus GG, 20 x 10(9) CFU/d, or placebo for 14 days. Subjects recorded the number of stools and their consistency daily for 21 days. The primary outcome was the proportion of patients who developed diarrhea in the first 21 days after enrollment. Weekly telephone follow-up was also performed. Results were analyzed in an intention-to-treat fashion.

RESULTS

Diarrhea developed in 39 (29.3%) of 133 patients randomized to receive Lactobacillus GG and in 40 (29.9%) of 134 patients randomized to receive placebo (P=.93). No additional difference in the rate of occurrence of diarrhea was found between treatment and placebo patients in a subgroup analysis of those treated with beta-lactam vs non-beta-lactam antibiotics. Too few patients had stool cultures, additional laboratory tests for diarrhea, or a positive diagnosis of Clostridium difficile infection to assess between-group differences.

CONCLUSION

Lactobacillus GG in a dose of 20 x 10(9) CFU/d did not reduce the rate of occurrence of diarrhea in this sample of 267 adult patients taking antibiotics initially administered in the hospital setting.

Electroconvulsive therapy and Friedreich's ataxia

Friedreich's ataxia is commonly associated with depression. Treatment of the depression can be difficult due to numerous morbid medical conditions. ECT is a safe and effective treatment option.

Perfluoroctylbromide as a gastrointestinal contrast agent for MR imaging: use with and without glucagon

The utility of perfluoroctylbromide (PFOB) as a gastrointestinal contrast agent for magnetic resonance (MR) imaging was evaluated with MR examinations performed in 30 subjects (16 healthy volunteers and 14 patients). Transaxial T1-, proton density-, and T2-weighted MR images were acquired in each subject before and after the administration of PFOB. The healthy volunteers each underwent two sets of post-PFOB MR examinations, one before and one after glucagon administration. The degree of bowel marking, clarity of bowel-wall visualization, ability to distinguish bowel from adjacent parenchymal organs, and severity of phase-encoding artifacts were independently analyzed by two reviewers. Oral administration of PFOB significantly (P less than .001) increased the percentage of bowel loops with low signal intensity. Subcutaneous administration of glucagon significantly (P less than .001) increased the clarity of bowel-wall visualization on post-PFOB MR studies. The severity of phase-encoding artifacts did not change substantially after administration of PFOB or glucagon.