Effect of nicotine- and tar-removed cigarette smoke extract on cancer metastasis

Cigarette smoking is known to impact the promotion of carcinogenesis and tumor metastasis. On the other hand, some components in smoke were found to have health-promoting effects, and cancer suppressor effects of components in tobacco smoke have attracted attention. Although some studies showed the cancer suppressive effect of cigarette smoke extract (CSE) in vitro study, the effect of CSE administration on cancer is controversial. In this study, we investigated the effect of CSE-administration on tumor metastasis in a spontaneous tumor metastasis model using B16-BL6 cells, which is more clinical conditions. C57BL/6NCr mice were subcutaneously inoculated B16-BL6 cells into the footpad of the right rear leg. CSE was intraperitoneally administrated for 28 days from the day of inoculation. At 2 weeks after inoculation, the primary focus was excised. Subsequently, survival days of the mice were recorded to determine the effect of CSE-administration on spontaneous metastasis. The effect of CSE, α, β-unsaturated ketones, and aldehydes on B16-BL6 cell invasiveness were confirmed by matrigel invasion assay. Survival days of mice injected with 100% CSE was significantly shortened than that of control. B16-BL6 cell invasiveness was accelerated by the treatment with 0.1% CSE and 3 μM of crotonaldehyde. Intraperitoneal CSE-administration may progress spontaneous metastasis of B16-BL6 cells via enhancement of B16-BL6 cell invasiveness. As the cause, we found that crotonaldehyde contained in CSE may enhance the invasion ability of cancer cells. To clarify the cancer-suppressing effect of tobacco components, the effect of crotonaldehyde-removed CSE on tumor should be assessed in detail. Keywords: cigarette smoke extract (CSE), metastasis, crotonaldehyde (CA), B16-BL6 mouse melanoma cells, invasion

OSW-1 Induces Apoptosis and Cyto-Protective Autophagy, and Synergizes with Doxorubicin on Spontaneous Metastasis of Triple Negative Breast Cancer

Background Triple-negative breast cancer (TNBC) is the most malignant subtype of breast cancer and chemotherapy using drugs such as doxorubicin is the main treatment strategy. However, drug resistance and dose-dependent toxicities restricted its clinical use. Natural products are major sources of anti-tumor drugs. OSW-1 is a natural compound that has shown strong anti-cancer effects in several cancer types, but its effects on the efficacies of chemotherapy in TNBC and the underlying mechanism remain unclear. Methods We investigated the effects of OSW-1 on the viabilities, apoptosis and autophagy in 4T1 and MDA-MB-231 cells. The synergistic effects of combination with OSW-1 and doxorubicin on TNBC growth and spontaneous metastasis were examined in vitro and in vivo. Results OSW-1 induces mitochondria-dependent apoptosis and cyto-protective autophagy in TNBC cells in vitro. In addition, OSW-1 and doxorubicin exhibits strong synergistic anti-TNBC capabilities both in vivo and in vitro. The combination treatment can strongly inhibit spontaneous metastasis in 4T1 model. Consistent with this inhibition, the proportion of CD8+ T lymphocytes in the lung microenvironment were significantly increased after combination treatment. Conclusions This study indicates that the combination therapy with natural compound and chemotherapeutic drug could be a promising anti-TNBC strategy which deserves further investigation.

Maturation, developmental site, and pathology dictate murine neutrophil function

Neutrophils have been implicated in poor outcomes in cancer and severe inflammation. We found that neutrophils expressing intermediate levels of Ly6G (Ly6GInt) were present in mouse cancer models and more abundant in those with high rates of spontaneous metastasis. Maturation, age, tissue localization and functional capacity all drive neutrophil heterogeneity. Recent studies have proposed various markers to distinguish between these heterogeneous sub-populations; however, these markers are limited to specific models of inflammation and cancer. Here, we identify and define Ly6G expression level as a robust and reliable marker to distinguish neutrophils at different stages of maturation. Ly6GInt neutrophils were bona fide immature neutrophils with reduced immune regulatory and adhesion capacity. Whereas the bone marrow is a more recognised site of granulopoiesis, the spleen also produces neutrophils in homeostasis and cancer. Strikingly, neutrophils matured faster in the spleen than in the bone marrow with unique transcriptional profiles. We propose that developmental origin is critical in neutrophil identity and postulate that neutrophils that develop in the spleen supplement the bone marrow by providing an intermediate more mature reserve before emergency haematopoiesis.

Annexin A1 Is Required for Efficient Tumor Initiation and Cancer Stem Cell Maintenance in a Model of Human Breast Cancer

Triple-negative breast cancer (TNBC) has a poor outcome compared to other breast cancer subtypes, and new therapies that target the molecular alterations driving tumor progression are needed. Annexin A1 is an abundant multi-functional Ca2+ binding and membrane-associated protein. Reported roles of Annexin A1 in breast cancer progression and metastasis are contradictory. Here, we sought to clarify the functions of Annexin A1 in the development and progression of TNBC. The association of Annexin A1 expression with patient prognosis in subtypes of TNBC was examined. Annexin A1 was stably knocked down in a panel of human and murine TNBC cell lines with high endogenous Annexin A1 expression that were then evaluated for orthotopic growth and spontaneous metastasis in vivo and for alterations in cell morphology in vitro. The impact of Annexin A1 knockdown on the expression of genes involved in mammary epithelial cell differentia tion and epithelial to mesenchymal transition was also determined. Annexin A1 mRNA levels correlated with poor patient prognosis in basal-like breast tumors and also in the basal-like 2 subset of TNBCs. Unexpectedly, loss of Annexin A1 expression had no effect on either primary tumor growth or spontaneous metastasis of MDA-MB-231_HM xenografts, but abrogated the growth rate of SUM149 orthotopic tumors. In an MMTV-PyMT driven allograft model of breast cancer, Annexin A1 depletion markedly delayed tumor formation in both immuno-competent and immuno-deficient mice and induced epithelial to mesenchymal transition and upregulation of basal markers. Finally, loss of Annexin A1 resulted in the loss of a discrete CD24+/Sca1− population containing putative tumor initiating cells. Collectively, our data demonstrate a novel cell-autonomous role for Annexin A1 in the promotion of tumor-forming capacity in a model of human breast cancer and suggest that some basal-like TNBCs may require high endogenous tumor cell Annexin A1 expression for continued growth.

CHD1 loss negatively influences metastasis-free survival in R0-resected prostate cancer patients and promotes spontaneous metastasis in vivo

The outcome of prostate cancer (PCa) patients is highly variable and depends on whether or not distant metastases occur. Multiple chromosomal deletions have been linked to early tumor marker PSA recurrence (biochemical relapse, BCR) after radical prostatectomy (RP), but their potential role for distant metastasis formation is largely unknown. Here, we specifically analyzed whether deletion of the tumor suppressor CHD1 (5q21) influences the post-surgical risk of distant metastasis and whether CHD1 loss directly contributes to metastasis formation in vivo. By considering >6800 patients we found that the CHD1 deletion negatively influences metastasis-free survival in R0 patients (HR: 2.32; 95% CI: 1.61, 3.33; p < 0.001) independent of preoperative PSA, pT stage, pN status, Gleason Score, and BCR. Moreover, CHD1 deletion predicts shortened BCR-free survival in pT2 patients and cancer-specific survival in all patients. In vivo, CHD1 loss increases spontaneous pulmonary metastasis formation in two distinct PCa models coupled with a higher number of multicellular colonies as compared to single-cell metastases. Transcriptome analyses revealed down-regulation of the PCa-specific metastasis suppressor and TGFβ signaling regulator PMEPA1 after CHD1 depletion in both tested PCa models. CHD1 loss increases the risk of postoperative metastasis in R0-resected PCa patients and promotes spontaneous metastasis formation in vivo.

SDF-1/CXCR4 inhibition prevents paradoxical generation of cisplatin-induced pro-metastatic niches

Platinum-based chemotherapy remains widely used in advanced non-small cell lung cancer (NSCLC) despite its ineffectiveness in long-term control of metastasis.Here, we uncover the interconnected pathways subtending cisplatin-induced metastasis promotion.We report that cisplatin treatment of tumor-free mice results in bone-marrow expansion of CCR2+CXCR4+Ly6Chigh inflammatory monocytes (IM) concomitantly with increased levels in the lungs of stromal SDF-1, the CXCR4 ligand. In experimental metastasis assays, cisplatin-induced IM favor tumor cells extravasation and expansion of CD133+CXCR4+ metastasis initiating cells (MICs), facilitating lung metastasis formation. At the primary tumor, cisplatin reduces tumor size but induces tumor release of SDF-1 triggering MICs expansion and recruitment of pro-invasive CXCR4+ macrophages. Co-recruitment of MICs and CCR2+CXCR4+ IM at SDF-1-enriched distant sites also promotes spontaneous metastasis. Combination treatment with a CXCR4 inhibitor prevents cisplatin-induced IM/MICs recruitment and interaction thus precluding metastasis overgrowth. Finally, we observe in NSCLC patients’ specimens that SDF-1 levels are higher in platinum-treated samples and correlate with worse outcome.Our findings suggest a possible novel combination therapy based on CXCR4 blockade to control metastatic disease, paradoxically promoted by cisplatin.