Dysfunctional circadian clock accelerates cancer metastasis by intestinal microbiota triggering accumulation of myeloid-derived suppressor cells.

Circadian homeostasis in mammals is a key intrinsic mechanism for responding to the external environment. However, the interplay between circadian rhythms and the tumor microenvironment (TME) and its influence on metastasis are still unclear. Here, in patients with colorectal cancer (CRC), disturbances of circadian rhythm and the accumulation of monocytes and granulocytes were closely related to metastasis. Moreover, dysregulation of circadian rhythm promoted lung metastasis of CRC by inducing the accumulation of myeloid-derived suppressor cells (MDSCs) and dysfunctional CD8+ T cells in the lungs of mice. Also, gut microbiota and its derived metabolite taurocholic acid (TCA) contributed to lung metastasis of CRC by triggering the accumulation of MDSCs in mice. Mechanistically, TCA promoted glycolysis of MDSCs epigenetically by enhancing mono-methylation of H3K4 of target genes and inhibited CHIP-mediated ubiquitination of PDL1. Our study links the biological clock with MDSCs in the TME through gut microbiota/metabolites in controlling the metastatic spread of CRC, uncovering a systemic mechanism for cancer metastasis.

Jianpi-Tiaoqi decoction inhibits tumour proliferation and lung metastasis in tumour-bearing mice with triple-negative breast cancer.

Traditional Chinese medicine, specifically the Jianpi Tiaoqi (JPTQ) decoction, has been explored for its role in treating breast cancer, particularly in inhibiting lung metastasis in affected mice. Our study evaluated the effects of JPTQ on several factors, including tumour growth, apoptosis, angiogenesis, epithelial-to-mesenchymal transition (EMT) and immune microenvironment regulation. We used bioluminescence imaging to observe in situ tumour growth and potential lung metastasis. Transcriptomic analysis provided insights into gene expression, whereas flow cytometry was used to examine changes in specific immune cells, such as CD4+ T cells and myeloid-derived suppressor cells. Several essential proteins and genes, including vascular endothelial growth factor (VEGF), matrix metalloprotein-9 (MMP-9) and B-cell lymphoma 2 (Bcl-2), were assessed through quantitative real-time polymerase chain reaction, western blotting and immunohistochemistry. Our findings showed that JPTQ treatment inhibited tumour proliferation in cancer-bearing mice. Bioluminescence imaging and pathological analysis indicated a reduction in lung metastasis. Transcriptome analysis of lung and tumour tissues indicated that the genes associated with EMT, angiogenesis, proliferation and apoptosis were regulated in the JPTQ-treated group. Kyoto Encyclopedia of Genes and Genomes analysis suggested enrichment of immune-related pathways. Flow cytometry indicated that JPTQ treatment reduced the proportion of monocyte-myeloid-derived suppressor cells in the lung and increased the number of CD4+ T cells in the peripheral blood and the number of T helper 1 (Th1) cells in the spleen (P < 0.05). E-cadherin and cleaved caspase 3 were upregulated, whereas Snail, Bcl-2, Ki67 and VEGF were downregulated in the lung and tumour tissues; moreover, the expression of MMP-9 was downregulated in the lung tissue (P < 0.05). In essence, JPTQ not only inhibits tumour growth in affected mice, but also promotes positive immune responses, reduces angiogenesis, boosts tumour cell apoptosis, reverses EMT and decreases breast cancer lung metastasis.

Pulmonary blastoma with a good prognosis: a case report and review of the literature.

Pulmonary blastoma (PB) is a rare, highly malignant tumor prone to distant metastasis and recurrence, and the prognosis of these patients is often poor. We report a case of metastatic PB with a good prognosis with the aim of providing data to support a clinical diagnosis and treatment. In December 2015, a 43-year-old male patient was admitted to our hospital because of a cough and blood-stained sputum. Positron emission-computed tomography showed massive high-density imaging in the lower lobe of the right lung, with a maximum cross-section of 76 × 58 mm. Thoracoscopic-assisted right lower lobectomy with lymph node dissection was performed. After 1 month, computed tomography showed a high possibility of metastasis. The patient then received docetaxel and cisplatin chemotherapy for a total of six courses. After chemotherapy, enhanced computed tomography showed considerable absorption of pleural effusion, and a left lobe pulmonary nodule was not detected. The postoperative pathological diagnosis was PB, and epithelial and mesenchymal differentiation components were observed. The patient continued to visit the hospital regularly for re-examination and imaging examinations. Currently, no signs of recurrence or distant metastasis have been detected.

Efficacy of denosumab treatment for lung metastasis secondary to proximal humerus chondroblastoma.

Chondroblastoma is a rare benign cartilaginous tumor that accounts for approximately 1% of bone tumors, but it can be associated with lung metastasis in extremely rare cases, leading to a poor prognosis and death. Herein, we report the case of a 19-year-old male patient who presented with an aggressive chondroblastoma of the proximal humerus and bilateral lung metastasis. The patient was treated with wide local resection, partial metastasectomy, and denosumab. Denosumab treatment was effective in controlling metastatic progression and preventing local recurrence.

Predictors of pulmonary metastases on chest computed tomography in children and adolescents with osteosarcoma-tips for qualifying patients for thoracotomy.

BACKGROUND: Osteosarcoma is the most common primary malignant bone tumour in children and adolescents. Lungs are the most frequent and often the only site of metastatic disease. The presence of pulmonary metastases is a significant unfavourable prognostic factor. Thoracotomy is strongly recommended in these patients, while computed tomography (CT) remains the gold imaging standard. The purpose of our study was to create tools for the CT-based qualification for thoracotomy in osteosarcoma patients in order to reduce the rate of useless thoracotomies. METHODS: Sixty-four osteosarcoma paediatric patients suspected of lung metastases on CT and their first-time thoracotomies (n = 100) were included in this retrospective analysis. All CT scans were analysed using a compartmental evaluation method based on the number and size of nodules. Calcification and location of lung lesions were also analysed. Inter-observer reliability between two experienced radiologists was assessed. The CT findings were then correlated with the histopathological results of thoracotomies. Various multivariate predictive models (logistic regression, classification tree and random forest) were built and predictors of lung metastases were identified. RESULTS: All applied models proved that calcified nodules on the preoperative CT scan best predict the presence of pulmonary metastases. The rating of the operated lung on the preoperative CT scan, dependent on the number and size of nodules, and the total number of nodules on this scan were also found to be important predictors. All three models achieved a relatively high sensitivity (72-92%), positive predictive value (81-90%) and accuracy (74-79%). The positive predictive value of each model was higher than of the qualification for thoracotomy performed at the time of treatment. Inter-observer reliability was at least substantial for qualitative variables and excellent for quantitative variables. CONCLUSIONS: The multivariate models built and tested in our study may be useful in the qualification of osteosarcoma patients for metastasectomy through thoracotomy and may contribute to reducing the rate of unnecessary invasive procedures in the future.

Clinical characteristics, survival analysis and influencing factors of distant metastasis in patients with acromelanomas: A retrospective study.

The prognosis of acromelanomas (AM) is worse. The objective of this study was to investigate the clinical features of distant metastasis of AM and the factors affecting the survival and prognosis of patients. In this study, a retrospective study was conducted to select 154 AM patients admitted to Nanjing Pukou People's Hospital from January 2018 to April 2021 for clinical research. The clinical characteristics of distant metastasis were statistically analyzed, and the survival curve was drawn with 5-year follow-up outcomes. The median survival time of the patients was calculated, and the clinicopathological features and peripheral blood laboratory indexes of the surviving and dead patients were analyzed. Logistic regression model was used to analyze the risk factors affecting the prognosis of AM patients. In this study, 154 patients with AM were treated, including 88 males and 76 females, aged from 27 to 79 years old, with an average age of (59.3 ±â€…11.7) years old. Among them, 90 cases had distant metastasis. The main metastatic sites were lung (47.78%) and lymph nodes (42.22%). Among them, single site metastasis accounted for 41.11% and multiple site metastasis 58.89%. 89 cases survived and 65 cases died. The survival time was 22 months to 60 months, and the median survival time was 48.0 months. The Breslow thickness, stage at diagnosis, distant metastasis, site of metastasis and ulceration were compared between the survival group and the death group (P < .05). serum lactate dehydrogenase (LDH), neutrophil-to-lymphocyte ratio (NLR) and lymphocyte monocyte ratio (LMR) were compared between the survival group and the death group (P < .05). The results of Logistic regression model showed that LDH ≥ 281 U/L, NLR ≥ 2.96, LMR ≤ 3.57, newly diagnosed stage > stage II, distant metastasis, multiple site metastasis and tumor ulcer were independent risk factors for poor prognosis of AM patients (P < .05). Patients with AM had a higher proportion of distant metastasis, mainly lung and lymph node metastasis. Increased LDH, increased NLR, decreased LMR, higher initial stage, distant metastasis, multiple site metastasis, and combined tumor ulcer were closely related to the poor prognosis of patients after surgery.

Extraneural metastatic ependymoma: distant metastasis to the pleura, lungs, lymph nodes and bone.

Ependymomas are neuroepithelial tumours arising from ependymal cells surrounding the cerebral ventricles that rarely metastasise to extraneural structures. This spread has been reported to occur to the lungs, lymph nodes, liver and bone. We describe the case of a patient with recurrent CNS WHO grade 3 ependymoma with extraneural metastatic disease. He was treated with multiple surgical resections, radiation therapy and salvage chemotherapy for his extraneural metastasis to the lungs, bone, pleural space and lymph nodes.

SDF-1 promotes metastasis of NSCLC by enhancing chemoattraction of megakaryocytes through the PI3K/Akt signaling pathway.

Lung cancer (LC) is the leading cause of cancer-associated deaths worldwide, among which non-small-cell lung cancer (NSCLC) accounts for 80%. Stromal cell-derived factor-1 (SDF-1) inhibition results in a significant depletion of NSCLC metastasis. Additionally, SDF-1 is the only natural chemokine known to bind and activate the receptor CXCR4. Thus, we attempted to clarify the molecular mechanism of SDF-1 underlying NSCLC progression. Transwell migration, adhesion, and G-LISA assays were used to assess megakaryocytic chemotaxis in vitro and in vivo in terms of megakaryocytic migration, adherence, and RhoA activation, respectively. Western blotting was used to assess PI3K/Akt-associated protein abundances in MEG-01 cells and primary megakaryocytes under the indicated treatment. A hematology analyzer and flow cytometry were used to assess platelet counts in peripheral blood and newly formed platelet counts in Lewis LC mice under different treatments. Immunochemistry and flow cytometry were used to measure CD41+ megakaryocyte numbers in Lewis LC mouse tissue under different treatments. ELISA was used to measure serum TPO levels, and H&E staining was used to detect NSCLC metastasis.SDF-1 receptor knockdown suppressed megakaryocytic chemotaxis in Lewis LC mice. SDF-1 receptor inhibition suppressed megakaryocytic chemotaxis via the PI3K/Akt pathway. SDF-1 receptor knockdown suppressed CD41+ megakaryocyte numbers in vivo through PI3K/Akt signaling. SDF-1 receptor inhibition suppressed CD41+ megakaryocytes to hinder NSCLC metastasis. SDF-1 facilitates NSCLC metastasis by enhancing the chemoattraction of megakaryocytes via the PI3K/Akt signaling pathway, which may provide a potential new direction for seeking therapeutic plans for NSCLC.

CLIP170 inhibits the metastasis and EMT of papillary thyroid cancer through the TGF-ß pathway.

Metastasis poses a significant challenge in combating tumors. Even in papillary thyroid cancer (PTC), which typically exhibits a favorable prognosis, high recurrence rates are attributed to metastasis. Cytoplasmic linker protein 170 (CLIP170) functions as a classical microtubule plus-end tracking protein (+TIP) and has shown close association with cell migration. Nevertheless, the specific impact of CLIP170 on PTC cells remains to be elucidated. Our analysis of the GEO and TCGA databases unveiled an association between CLIP170 and the progression of PTC. To explore the impact of CLIP170 on PTC cells, we conducted various assays. We evaluated its effects through CCK-8, wound healing assay, and transwell assay after knocking down CLIP170. Additionally, the influence of CLIP170 on the cellular actin structure was examined via immunofluorescence; we further investigated the molecular expressions of epithelial-mesenchymal transition (EMT) and the transforming growth factor-ß (TGF-ß) signaling pathways through Western blotting and RT-qPCR. These findings were substantiated through an in vivo nude mouse model of lung metastasis. We observed a decreased expression of CLIP170 in PTC in contrast to normal thyroid tissue. Functionally, the knockdown of CLIP170 (CLIP170KD) notably enhanced the metastatic potential and EMT of PTC cells, both in vitro and in vivo. Mechanistically, CLIP170KD triggered the activation of the TGF-ß pathway, subsequently promoting tumor cell migration, invasion, and EMT. Remarkably, the TGF-ß inhibitor LY2157299 effectively countered TGF-ß activity and significantly reversed tumor metastasis and EMT induced by CLIP170 knockdown. In summary, these findings collectively propose CLIP170 as a promising therapeutic target to mitigate metastatic tendencies in PTC.

Overcoming Nutrient Stress: Integrin αvß3-Driven Metabolic Adaptation Supports Tumor Initiation.

Nutrient stress accompanies several stages of tumor progression, including metastasis formation. Metabolic reprogramming is a hallmark of cancer, and it has been associated with stress tolerance and anchorage-independent cell survival. Adaptive responses are required to support cancer cell survival under these conditions. In this issue of Cancer Research, Nam and colleagues showed that the extracellular matrix (ECM) receptor integrin ß3 was upregulated in lung cancer cells in response to nutrient starvation, resulting in increased cell survival that was independent from ECM binding. Delving into the molecular mechanisms responsible for this, the authors found that integrin ß3 promoted glutamine metabolism and oxidative phosphorylation (OXPHOS) by activating a Src/AMPK/PGC1α signaling pathway. Importantly, in vivo experiments confirmed that OXPHOS inhibition suppressed tumor initiation in an orthotopic model of lung cancer, while ß3 knockout completely abrogated tumor initiation. These observations indicate that targeting signaling pathways downstream of αvß3 could represent a promising therapeutic avenue to prevent lung cancer progression and metastasis. See related article by Nam et al., p. 1630.

Patterns of distant metastasis and survival outcomes in de novo metastatic breast cancer according to age groups.

Background: Is de novo metastatic breast cancer (dnMBC) the same disease in the elderly as in younger breast cancer remains unclear. This study aimed to determine the metastatic patterns and survival outcomes in dnMBC according to age groups. Methods: We included patients from the Surveillance Epidemiology and End Results program. Chi-square test, multivariate logistic regression analyses, and multivariate Cox regression models were used for statistical analyses. Results: A total of 17719 patients were included. There were 3.6% (n=638), 18.6% (n=3290), 38.0% (n=6725), and 39.9% (n=7066) of patients aged <35, 35-49, 50-64, and ≥65 years, respectively. Older patients had a significantly higher risk of lung metastasis and a significantly lower risk of liver metastasis. There were 19.1%, 25.6%, 30.9%, and 35.7% of patients with lung metastasis in those aged <35, 35-49, 50-64, and ≥65 years, respectively. Moreover, the proportion of liver metastasis was 37.6%, 29.5%, 26.3%, and 19.2%, respectively. Age was the independent prognostic factor associated with breast cancer-specific survival (BCSS) and overall survival (OS). Those aged 50-64 years had significantly inferior BCSS (P<0.001) and OS (P<0.001) than those aged <35 years. Patients aged ≥65 years also had significantly lower BCSS (P<0.001) and OS (P<0.001) than those aged <35 years. However, similar outcomes were found between those aged 35-49 and <35 years. Conclusion: Our study suggests that different age groups may affect the metastatic patterns among patients with dnMBC and the survival of younger patients is more favorable than those of older patients.

Case report: Sintilimab combined with anlotinib as neoadjuvant chemotherapy for metastatic bone tumor resection in patients with PSC.

Background: Pulmonary sarcomatoid carcinoma (PSC) is a rare subtype of non-small-cell lung cancer (NSCLC), which is resistant to chemotherapy and radiotherapy with a poor prognosis. PSC is highly malignant and is prone to recurrence even after surgery. The programmed death-ligand 1 (PD-L1) tumor cell proportion score (TPS) 5%, TERT and TP53 gene mutations were detected in this patient accompanied by multiple metastatic sites. The anlotinib is a novel multitarget tyrosine kinase inhibitor (TKI) that could be effective for advanced NSCLC and some sarcoma patients. Limited clinical trials and case reports have shown that PSC patients with gene mutations and PD-L1 expression have good responses to multitarget antiangiogenic drug and immune checkpoint inhibitors (ICIs). In this article, we reported a case with metastatic PSC diagnosed by Computed Tomography (CT)-guided needle biopsy treated with immunotherapy combined with antiangiogenic drugs as a neoadjuvant chemotherapy (NACT). PSC is controlled and the patient achieves successfully limb salvage treatment by surgical resection. Therefore, targeted therapy and immunotherapy can provide sufficient surgical opportunities for limb salvage in the treatment of metastatic PSC patients. Case summary: A 69-year-old male diagnosed with malignant bone tumor in the proximal femur was admitted to our hospital in June 2022 with recurrent fever as well as swelling and pain in the left thigh for twenty days. The initial computed tomography (CT) scan of the chest showed a pulmonary cavity (20 mm × 30 mm) and scattered lung masses. Subsequently, he underwent a CT-guided needle biopsy to distinguish the essence of osteolytic bone destruction and soft tissue mass in the left proximal femur which showed metastatic sarcomatoid carcinoma histology. Genetic testing revealed TERT c.-124C mutation (abundance 8.81%), TP53 p.R342 mutation (abundance 11.35%), tumor mutational burden (TMB) 7.09 muts/Mb, microsatellite stability (MSS), and PD-L1 (SP263) TPS 5% were also detected. The patient was tentatively treated with a combination of antiangiogenic drug and PD-1 inhibitor. After one course, the tumor volume significantly reduced in magnetic resonance imaging (MRI) and pathological fracture occurred in the femur after combined treatment. The patient received proximal femoral tumor resection and prosthesis replacement after defervescence. Sequentially sintilimab with anlotinib were administered for over 1 year. Finally, the local tumor was well controlled, and no obvious drug-related adverse reactions were observed. The lesions in the lung remained in partial response (PR) for more than 16 months and complete response (CR) of metastatic tumor in the proximal femur was observed through imaging examinations. Conclusion: This is the first reported case of a metastatic PSC in femur showing a favorable response to the treatment consisting of anlotinib combined with sintilimab. This case suggests that antiangiogenic therapy combined with immunotherapy may benefit patients with metastatic PSC in the preoperative adjuvant therapy for limb salvage.

The F-actin bundler SWAP-70 promotes tumor metastasis.

Dynamic rearrangements of the F-actin cytoskeleton are a hallmark of tumor metastasis. Thus, proteins that govern F-actin rearrangements are of major interest for understanding metastasis and potential therapies. We hypothesized that the unique F-actin binding and bundling protein SWAP-70 contributes importantly to metastasis. Orthotopic, ectopic, and short-term tail vein injection mouse breast and lung cancer models revealed a strong positive dependence of lung and bone metastasis on SWAP-70. Breast cancer cell growth, migration, adhesion, and invasion assays revealed SWAP-70's key role in these metastasis-related cell features and the requirement for SWAP-70 to bind F-actin. Biophysical experiments showed that tumor cell stiffness and deformability are negatively modulated by SWAP-70. Together, we present a hitherto undescribed, unique F-actin modulator as an important contributor to tumor metastasis.

HIF2A mediates lineage transition to aggressive phenotype of cancer-associated fibroblasts in lung cancer brain metastasis.

Brain metastasis is the most devasting form of lung cancer. Recent studies highlight significant differences in the tumor microenvironment (TME) between lung cancer brain metastasis (LCBM) and primary lung cancer, which contribute significantly to tumor progression and drug resistance. Cancer-associated fibroblasts (CAFs) are the major component of pro-tumor TME with high plasticity. However, the lineage composition and function of CAFs in LCBM remain elusive. By reanalyzing single-cell RNA sequencing (scRNA-seq) data (GSE131907) from lung cancer patients with different stages of metastasis comprising primary lesions and brain metastasis, we found that CAFs undergo distinctive lineage transition during LCBM under a hypoxic situation, which is directly driven by hypoxia-induced HIF-2α activation. Transited CAFs enhance angiogenesis through VEGF pathways, trigger metabolic reprogramming, and promote the growth of tumor cells. Bulk RNA sequencing data was utilized as validation cohorts. Multiplex immunohistochemistry (mIHC) assay was performed on four paired samples of brain metastasis and their primary lung cancer counterparts to validate the findings. Our study revealed a novel mechanism of lung cancer brain metastasis featuring HIF-2α-induced lineage transition and functional alteration of CAFs, which offers potential therapeutic targets.

MerTK Drives Proliferation and Metastatic Potential in Triple-Negative Breast Cancer.

Triple-negative breast cancer (TNBC) is characterized by the absence of the estrogen receptor, progesterone receptor, and receptor tyrosine kinase HER2 expression. Due to the limited number of FDA-approved targeted therapies for TNBC, there is an ongoing need to understand the molecular underpinnings of TNBC for the development of novel combinatorial treatment strategies. This study evaluated the role of the MerTK receptor tyrosine kinase on proliferation and invasion/metastatic potential in TNBC. Immunohistochemical analysis demonstrated MerTK expression in 58% of patient-derived TNBC xenografts. The stable overexpression of MerTK in human TNBC cell lines induced an increase in proliferation rates, robust in vivo tumor growth, heightened migration/invasion potential, and enhanced lung metastases. NanoString nCounter analysis of MerTK-overexpressing SUM102 cells (SUM102-MerTK) revealed upregulation of several signaling pathways, which ultimately drive cell cycle progression, reduce apoptosis, and enhance cell survival. Proteomic profiling indicated increased endoglin (ENG) production in SUM102-MerTK clones, suggesting that MerTK creates a conducive environment for increased proliferative and metastatic activity via elevated ENG expression. To determine ENG's role in increasing proliferation and/or metastatic potential, we knocked out ENG in a SUM102-MerTK clone with CRISPR technology. Although this ENG knockout clone exhibited similar in vivo growth to the parental SUM102-MerTK clone, lung metastasis numbers were significantly decreased ~4-fold, indicating that MerTK enhances invasion and metastasis through ENG. Our data suggest that MerTK regulates a unique proliferative signature in TNBC, promoting robust tumor growth and increased metastatic potential through ENG upregulation. Targeting MerTK and ENG simultaneously may provide a novel therapeutic approach for TNBC patients.

Tumor-Intrinsic Enhancer of Zeste Homolog 2 Controls Immune Cell Infiltration, Tumor Growth, and Lung Metastasis in a Triple-Negative Breast Cancer Model.

Triple-negative breast cancer (TNBC) is an aggressive and highly metastatic type of tumor. TNBC is often enriched in tumor-infiltrating neutrophils (TINs), which support cancer growth in part by counteracting tumor-infiltrating lymphocytes (TILs). Prior studies identified the enhancer of zeste homolog 2 (EZH2) as a pro-tumor methyltransferase in primary and metastatic TNBCs. We hypothesized that EZH2 inhibition in TNBC cells per se would exert antitumor activity by altering the tumor immune microenvironment. To test this hypothesis, we used CRISPR to generate EZH2 gene knockout (KO) and overexpressing (OE) lines from parent (wild-type-WT) 4T1 cells, an established murine TNBC model, resulting in EZH2 protein KO and OE, respectively. In vitro, EZH2 KO and OE cells showed early, transient changes in replicative capacity and invasiveness, and marked changes in surface marker profile and cytokine/chemokine secretion compared to WT cells. In vivo, EZH2 KO cells showed significantly reduced primary tumor growth and a 10-fold decrease in lung metastasis compared to WT cells, while EZH2 OE cells were unchanged. Compared to WT tumors, TIN:TIL ratios were greatly reduced in EZH2 KO tumors but unchanged in EZH2 OE tumors. Thus, EZH2 is key to 4T1 aggressiveness as its tumor-intrinsic knockout alters their in vitro secretome and in vivo primary tumor growth, TIN/TIL poise, and metastasis.

Blocking the angiopoietin-2-dependent integrin ß-1 signaling axis abrogates small cell lung cancer invasion and metastasis.

Small cell lung cancer (SCLC) is the most aggressive lung cancer entity with an extremely limited therapeutic outcome. Most patients are diagnosed at an extensive stage. However, the molecular mechanisms driving SCLC invasion and metastasis remain largely elusive. We used an autochthonous SCLC mouse model and matched samples from patients with primary and metastatic SCLC to investigate the molecular characteristics of tumor metastasis. We demonstrate that tumor cell invasion and liver metastasis in SCLC are triggered by an Angiopoietin-2 (ANG-2)/Integrin ß-1-dependent pathway in tumor cells, mediated by focal adhesion kinase/Src kinase signaling. Strikingly, CRISPR-Cas9 KO of Integrin ß-1 or blocking Integrin ß-1 signaling by an anti-ANG-2 treatment abrogates liver metastasis formation in vivo. Interestingly, analysis of a unique collection of matched samples from patients with primary and metastatic SCLC confirmed a strong increase of Integrin ß-1 in liver metastasis in comparison with the primary tumor. We further show that ANG-2 blockade combined with PD-1-targeted by anti-PD-1 treatment displays synergistic treatment effects in SCLC. Together, our data demonstrate a fundamental role of ANG-2/Integrin ß-1 signaling in SCLC cells for tumor cell invasion and liver metastasis and provide a potentially new effective treatment strategy for patients with SCLC.