Unbiased metastatic niche-labeling identifies estrogen receptor-positive macrophages as a barrier of T cell infiltration during bone colonization

Microenvironment niches determine cellular fates of metastatic cancer cells. However, robust and unbiased approaches to identify niche components and their molecular profiles are lacking. We established Sortase A-Based Microenvironment Niche Tagging (SAMENT), which selectively labels cells encountered by cancer cells during metastatic colonization. SAMENT was applied to multiple cancer models colonizing the same organ and the same cancer to different organs. Common metastatic niche features include macrophage enrichment and T cell depletion. Macrophage niches are phenotypically diverse between different organs. In bone, macrophages express the estrogen receptor alpha (ERα) and exhibit active ERα signaling in male and female hosts. Conditional knockout of Esr1 in macrophages significantly retarded bone colonization by allowing T cell infiltration. ERα expression was also discovered in human bone metastases of both genders. Collectively, we identified a unique population of ERα+ macrophages in the metastatic niche and functionally tied ERα signaling in macrophages to T cell exclusion during metastatic colonization.

HIGHLIGHTS

SAMENT is a robust metastatic niche-labeling approach amenable to single-cell omics.Metastatic niches are typically enriched with macrophages and depleted of T cells.Direct interaction with cancer cells induces ERα expression in niche macrophages. Knockout of Esr1 in macrophages allows T cell infiltration and retards bone colonization.

Osteoprogenitor-GMP crosstalk underpins solid tumor-induced systemic immunosuppression and persists after tumor removal

Remote tumors disrupt the bone marrow (BM) ecosystem (BME), eliciting the overproduction of BM-derived immunosuppressive cells. However, the underlying mechanisms remain poorly understood. Herein, we characterized breast and lung cancer-induced BME shifts pre- and post-tumor removal. Remote tumors progressively lead to osteoprogenitor (OP) expansion, hematopoietic stem cell dislocation, and CD41- granulocyte-monocyte progenitor (GMP) aggregation. The tumor-entrained BME is characterized by co-localization between CD41- GMPs and OPs. OP ablation abolishes this effect and diminishes abnormal myeloid overproduction. Mechanistically, HTRA1 carried by tumor-derived small extracellular vesicles upregulates MMP-13 in OPs, which in turn induces the alterations in the hematopoietic program. Importantly, these effects persist post-surgery and continue to impair anti-tumor immunity. Conditional knockout or inhibition of MMP-13 accelerates immune reinstatement and restores the efficacies of immunotherapies. Therefore, tumor-induced systemic effects are initiated by OP-GMP crosstalk that outlasts tumor burden, and additional treatment is required to reverse these effects for optimal therapeutic efficacy.

Campers' diarrhea outbreak traced to water-sewage link

From June through September 1979, diarrheal illness occurred in an estimated 1,850 persons who had camped at a private campground in Arizona. Illness occurred more frequently among campers at that campground than among those in the adjacent State park (P less than 0.0001). The same well served both the private and the State campgrounds as the source of drinking water, but that water was distributed to the two campgrounds through separate lines. Illness was significantly associated with drinking water at the campsite (P less than 0.0001), drinking larger quantities of campsite water (P less than 0.001), and camping on the southwest side of the campground (P less than 0.001). Samples of the water collected from the system during January through June contained no coliform bacteria. However, all those samples had been collected from the State park only. Of the 11 water samples submitted for bacteriological analyses during the summer, 3 had high levels of bacteria. Excavation of the water system uncovered a direct cross connection between the potable water system and a sewage-effluent irrigation system. This outbreak calls attention to the importance of designing, maintaining, and monitoring potable water systems properly, especially those proximate to wastewater re-use systems.

An outbreak of multiple-drug-resistant Salmonella enteritis from raw milk

In early 1983, an outbreak of illness caused by raw milk contaminated with multiple-antimicrobial-resistant Salmonella typhimurium occurred in Arizona. One of the cases involved a 72-year-old woman who died with Salmonella enteritis and sepsis that had not responded to treatment with chloramphenicol. The S typhimurium isolates from this patient, from other ill persons, and from raw milk were resistant to ampicillin, chloramphenicol, kanamycin sulfate, streptomycin, sulfonamide, and tetracycline. These resistances were mediated by a 105-megadalton R plasmid. During the epidemic period, 43% of the S typhimurium isolates submitted to the Arizona Department of Health Services were resistant to chloramphenicol, and 80% of these possessed the same plasmid resistance. Although there was evidence of spread of the S typhimurium in the community, there was no evidence of spread of this Salmonella R plasmid to the normal flora of patients or their family members a median of 14 weeks after the infection. This outbreak demonstrates the ability of drug-resistant Salmonella to spread from the animal to the human reservoir and, in a suitable host, produce a fatal infection.

Reye's syndrome and salicylate use

During an outbreak of influenza A, seven patients with Reye's syndrome and 16 ill classmate control subjects were evaluated for characteristics of the patients' prodromal illness and the control subjects illness and for medication usage. Patients during the prodrome and control subjects had similar rates of sore throat, coryza, cough, headache, and gastrointestinal complaints except for documented fever which occurred significantly more often in patients than in control subjects (P = .05). While medications which did not contain salicylate were taken as frequently by patients as control subjects, patients took more salicylate-containing medications than did control children (P < .01). All seven patients took salicylate whereas only eight of 16 control subjects did so (P < .05). Patients took larger doses of salicylate than did the entire control group (P < .01). When the eight control subjects who took salicylate were compared with the patients, the patients still tended to take larger doses (P = .08). Patients with fever took salicylate more frequently than control subjects with fever (P < .01). In addition, salicylate consumption was correlated with severity of Reye's syndrome (P < .05). It is postulated that salicylate, operating in a dose-dependent manner, possibly potentiated by fever, represents a primary causative agent of Reye's syndrome.