Interleukin-6 trans-signaling is a candidate mechanism to drive progression of human DCCs during periods of clinical latency

Abstract

28Although thousands of breast cancer cells disseminate and home to bone marrow until 29 primary surgery, usually less than a handful will succeed in establishing manifest 30 metastases months to years later. To identify signals that support survival or outgrowth 31 in patients, we profiled rare bone marrow-derived disseminated cancer cells (DCCs) 32 long before manifestation of metastasis and identified IL6/PI3K-signaling as candidate 33 pathway for DCC activation. Surprisingly, and similar to mammary epithelial cells, 34DCCs lacked membranous IL6 receptor expression and mechanistic dissection 35 revealed IL6 trans-signaling to regulate a stem-like state of mammary epithelial cells 36 via gp130. Responsiveness to IL6 trans-signals was found to be niche-dependent as 37 bone marrow stromal and endosteal cells down-regulated gp130 in premalignant 38 mammary epithelial cells as opposed to vascular niche cells. PIK3CA activation 39 rendered cells independent from IL6 trans-signaling. Consistent with a bottleneck 40 function of microenvironmental DCC control, we found PIK3CA mutations highly 41 associated with late-stage metastatic cells while being extremely rare in early DCCs. 42Our data suggest that the initial steps of metastasis formation are often not cancer cell-43 autonomous, but also depend on microenvironmental signals. 44Word count: 175 45 46 47 48 low frequency of BM-DCCs (<10 -6 ), we either injected CD45 depleted or EpCAM-98 enriched BM cells or generated and transplanted spheres as these have a higher 99 engraftment-likelihood 9 . In total, we tested 42 patient samples and different routes of 100 application, including sub-cutaneous, orthotopic (site of origin), intra-femoral and intra-101 venous injection. We then assessed tumor formation at the cutaneous injection sites 102 and metastatic spread to lungs or BM. BM-derived DCCs from M1-stage patients 103 engrafted in two out of four cases. In contrast, early DCCs from 42 M0-stage patients 104 did not establish xenografts (Fig. 1a, b), neither at the injection sites nor in the lungs 105 (p = 0.006; Fisher's exact test). We also explored the presence of minimal systemic 106 cancer by testing for human cytokeratin (CK) or EpCAM-positive cells in murine BM. 107Interestingly, albeit DCCs of non-metastatic patients did not expand in mice, they 108 survived in murine BM in 4 out of 42 cases. We detected human EpCAM + or CK + DCCs 109 at a frequency of 1-5 DCCs/million BM cells 4-14 weeks after injection of CD45-110 depleted human BM cells (Fig. 1c). For one of these rare events we could not only 111 prove human and epithelial, but also malignant origin by single cell copy number 112 alteration (CNA) analysis (Fig. 1d). 113In summary and consistent with our findings in melanoma, early DCCs from patients 114 without manifest metastasis failed to generate xenografts. Besides lower absolute cell 115 numbers and fewer genetic alterations (see below), microenvironmental dependence 116 of early DCCs could account for these results. We therefore decided to retrieve ...

Dormancy-inducing 3D-engineered matrix uncovers mechanosensitive and drug protective FHL2-p21 signaling axis

“…3b-e). This is in line with a recent study showing IL6 pathway activation in patient-derived early disseminated BCC in bone marrow (30).…”

Taxane chemotherapy leads to breast cancer dormancy escape by stromal injury mediated IL-6/MAP2K signaling

“…By using single-cell transcriptomic and pathway analysis, we found that IL-6 and G-CSF engagement in non-canonical signaling via the ERK/MAPK pathway, involved in fibrosis and wound healing response (52,53), to be crucial in cancer cells outgrowth (Fig. 3), instead of the canonical JAK/STAT signaling pathway involved in inflammatory response as shown by previous studies (17,51). The gene signatures identified in the chemotherapy group agreed with previous studies on dormant-emergent cancer and chemoresistance (18,42).…”

“…Clinical data from several studies show that taxane therapy increases serum IL-6 and G-CSF levels in patients (45,46) and that higher levels of serum IL-6 is a prognostic marker for early breast cancer recurrence in patients receiving systemic therapy (47,48). Additionally, IL-6 and G-CSF have been widely implicated in cancer invasiveness (49,50) and recent studies have also shown a role of trans-IL-6 activating JAK/STAT signaling in dormancy awakening (51). However, the mechanistic role of IL-6 and G-CSF in inducing dormancy escape has not been investigated.…”

TGF-β: an active participant in the immune and metabolic microenvironment of multiple myeloma

“…Consequently, inhibiting TAK1 disrupts MM-BMSC adhesion, inhibits osteoclast (OC) genesis, and may revive osteoblastic activity [4]. Melanie Werner-Klein et al determined that the IL-6/PI3K pathway plays a significant role in activating disseminated cancer cells (DCCs) despite their lack of membrane-bound IL-6 receptors, with IL-6 trans-signaling prompting a stem-like state in mammary epithelial cells through gp130 [34]. Further research by Matthew Ho and his team demonstrated that disabling Histone deacetylase 3 (HDAC3) via knock-out (KO), knock-down (KD), or pharmacological methods in BMSCs reduces myeloma cell proliferation, effectiveness confirmed in patient-derived myeloma cell cultures with BMSCs [35].…”