Extracellular vesicles in fatty liver disease and steatohepatitis: Role as biomarkers and therapeutic targets

Non-alcoholic fatty liver disease (NAFLD) and alcohol-associated liver disease (ALD) are characterized by lipid deposition in hepatocytes in the absence or presence of excessive alcohol consumption, respectively, ranging from simple steatosis to non-alcoholic steatohepatitis (NASH) or alcoholic hepatitis (AH) and from mild fibrosis to cirrhosis. Fatty liver disease and steatohepatitis similarly occur in individuals who have both metabolic syndrome and excessive alcohol intake; therefore, the single overarching term metabolic associated fatty liver disease (MAFLD) has been proposed to better reflect these risk factors and the continuity of disease progression. Extracellular vesicles (EVs) are membrane-bound endogenous nanoparticles released into the extracellular space by a majority of cell types. Liver disease-related EVs contain a variety of cellular cargo and are internalized into target cells resulting in the transfer of bioinformation reflecting the state of the donor cell to the recipient. Furthermore, EV composition can be used to identify the degree and type of liver disease, suggesting that EV composition may be a useful biomarker. With regard to MAFLD, the presence of metabolic risk factors, such as insulin resistance, will be indicated by adipose tissue-derived EVs and with that comes the potential to use as a clinical monitor of overall metabolic status. However, the inhibition of specific EV composition may be difficult to implement as a real-world therapeutic approach. Current global evidence shows that mesenchymal stem cell (MSCs)-derived EVs (MSC-EVs) play an important role in regulating the immune response, which has spawned a clinical trial to treat liver disease.     

Alcohol-related diseases and liver metastasis: Role of cell-free network communication

Alcohol intake is a risk factor for cancer development and metastatic disease progression. Extracellular vesicle (EV)-mediated interorgan communication is assumed to be significant in boosting tumorigenic pathways and disease progression. Recent research indicates that exosomes have a variety of roles in the development of cancer during pathophysiological conditions. The involvement of EV signaling during cancer progression in the alcohol environment is unknown. Therefore, understanding communication networks and the role of EVs as biomarkers can contribute significantly to developing strategies to address the serious public health problems associated with alcohol consumption and cancer.     

A new model of interactive effects of alcohol and high-fat diet on hepatic fibrosis

Background: Alcoholic steatohepatitis (ASH) and nonalcoholic steatohepatitis (NASH) are the most frequent conditions leading to elevated liver enzymes and liver cirrhosis, respectively, in the Western world. However, despite strong epidemiological evidence for combined effects on the progression of liver injury, the mutual interaction of the pathophysiological mechanisms is incompletely understood. The aim of this study was to establish and analyze an experimental murine model, where we combined chronic alcohol administration with a NASH‐inducing high‐fat (HF) diet. Methods: Balb/c mice were randomly allocated into 4 experimental groups receiving (i) standard chow, (ii) an HF diet, (iii) alcohol in drinking water (increasing concentrations up to 5%), or (iv) an HF diet and alcohol ad libitum for 6 weeks. Results: An HF diet significantly induced hepatic triglyceride accumulation and expression of proinflammatory genes (p47^phox and tumor necrosis factor), while the effects of alcohol alone were less pronounced. However, in combination with HF diet, alcohol significantly enhanced proinflammatory gene expression compared to the HF diet alone. Furthermore, alcohol as well as HF diet led to a marked increase in profibrogenic genes (collagen type I and transforming growth factor‐β), activation of hepatic stellate cells, and extracellular matrix deposition in the liver tissue, and noteworthy, the combination of both alcohol and HF diet led to a further marked induction of hepatic fibrosis. Moreover, endotoxin levels in the portal circulation were significantly elevated in mice that received alcohol or HF diet and were further significantly increased in those receiving both. Furthermore and surprisingly, HF diet alone and in combination with alcohol led to a markedly increased hepatic expression of the endotoxin receptor Toll‐like receptor 4 (TLR4), which is known to play a crucial role in hepatic fibrosis. Conclusions: In summary, this new model allows the investigation of isolated or joint effects of alcohol and HF diet on hepatic injury, where alcohol and HF diet appear to act synergistically on the development of hepatic fibrosis, potentially via enhanced TLR4 signaling.     

Hepatic androgen receptor suppresses hepatocellular carcinoma metastasis through modulation of cell migration and anoikis

Early reports suggested androgen/androgen receptor (AR) signals promote hepatocarcinogenesis. However, all antiandrogen clinical trials failed in advanced hepatocellular carcinoma (HCC) without reasonable explanations. We examined AR functions in HCC cancer metastasis in this study. We examined hepatic AR roles in HCC metastasis by comparing liver hepatocyte AR knockout and wildtype in a carcinogen-induced HCC mouse model. We examined tumor histology, cancer metastatic risks, and cancer survival in vivo, as well as cell anoikis and migration using primary hepatic tumor culture in vitro. We also examined therapeutic potentials of AR expression combined with the molecular targeting agent sorafenib in an HCC metastasis mouse model. We found a novel cancer phenotype in which mice lacking hepatic AR developed more undifferentiated tumors and larger tumor size at the metastatic stage. These mice also died earlier with increased lung metastasis, suggesting that hepatic AR may play dual yet opposite roles to promote HCC initiation but suppress HCC metastasis. Mechanistic dissection found that hepatic AR could enhance anoikis and suppress migration of HCC cells by way of suppression of p38 phosphorylation/activation and the nuclear factor kappa B (NF-κB)/matrix metallopeptidase 9 (MMP9) pathway, respectively. In addition, the in vivo preclinical trials concluded that a combination therapy of increased AR expression and reduced multiple-kinase inhibitor (sorafenib) exhibited better therapeutic efficacy. CONCLUSION: Our study demonstrates that AR could orchestrate intrahepatic signaling hierarchies and cellular behaviors, consequently affect HCC progression. Results from combination therapy shed light on developing new therapeutic paradigms for battling HCC at later metastatic stages.     

Management of alcoholic hepatitis: A clinical perspective

Alcohol-associated liver disease is the primary cause of liver-related mortality worldwide and one of the most common indications for liver transplantation. Alcoholic hepatitis represents the most acute and severe manifestation of alcohol-associated liver disease and is characterized by a rapid onset of jaundice with progressive inflammatory liver injury, worsening of portal hypertension, and an increased risk for multiorgan failure in patients with excessive alcohol consumption. Severe alcoholic hepatitis is associated with a poor prognosis and high short-term mortality. During the COVID-19 pandemic, rates of alcohol-associated hepatitis have increased significantly, underscoring that it is a serious and growing health problem. However, adequate management of alcohol-associated hepatitis and its complications in everyday clinical practice remains a major challenge. Currently, pharmacotherapy is limited to corticosteroids, although these have only a moderate effect on reducing short-term mortality. In recent years, translational studies deciphering key mechanisms of disease development and progression have led to important advances in the understanding of the pathogenesis of alcoholic hepatitis. Emerging pathophysiology-based therapeutic approaches include anti-inflammatory agents, modifications of the gut-liver axis and intestinal dysbiosis, epigenetic modulation, antioxidants, and drugs targeting liver regeneration. Concurrently, evidence is increasing that early liver transplantation is a safe treatment option with important survival benefits in selected patients with severe alcoholic hepatitis not responding to medical treatment. This narrative review describes current pathophysiology and management concepts of alcoholic hepatitis, provides an update on emerging treatment options, and focuses on the need for holistic and patient-centred treatment approaches to improve prognosis.     

An update and our experience with metastatic liver disease

Metastatic liver disease remains a challenging and life-threatening clinical situation with an obscure and dismal prognosis and outcome. The liver is the most common site of metastatic spread of colorectal cancer and nearly half of the patients with colorectal cancer ultimately develop liver metastasis during the course of their diseases. Death from colorectal cancer is often a result of liver metastases. Over half of these patients die from their metastatic liver diseases. At the time of diagnosis, hepatic metastases are present in 15-25% of patients, and another 25-50% will develop metachronous liver metastases within 3 years following resection of the primary tumor. Over the last decade, there have been tremendous advances in the treatment of metastatic liver disease. Hepatic resection still remains the gold standard for the treatment of metastatic lesions which are amenable to surgery. Unfortunately, up to 40 percent of patients are identified as having additional disease at the time of exploration, and 20 percent are found to be unresectable. Regional therapies such as radiofrequency ablation, microwave ablation and cryotherapy may be offered to patients with isolated unresectable metastases. Other options like hepatic artery chemotherapy and chemoembolization, portal vein embolization and immunotherapy also play a vital role in management of metastatic liver disease when used in combination with other therapies. This article reviews the history of metastatic liver disease, epidemiology, diagnosis and various treatment modalities available for liver metastases along with our experience in management of advance metastatic liver disease.     

Pathophysiological similarities and synergisms in alcoholic and non-alcoholic steatohepatitis

Chronic alcohol consumption is one of the main etiological factors for liver disease worldwide, however only a fraction of drinkers develop significant hepatic inflammation (alcoholic steatohepatitis), and even less progress to significant hepatic fibrosis and cirrhosis. The pathophysiological significance of hepatic lipid accumulation in the absence of significant alcohol consumption is also increasingly recognized. Non-alcoholic fatty liver disease (NAFLD) is regarded as the hepatic manifestation of the metabolic syndrome, and it is the most common cause of liver enzyme elevations in Western countries. Similarly to alcoholic liver disease, NAFLD encompasses mild hepatic steatosis to non-alcoholic steatohepatitis with significant necroinflammation and progressive fibrosis. Several clinical studies suggest a strong causative link between the consumption of alcohol and progressive liver disease in individuals with high fat intake and/or diabetes. However, it is incompletely understood how alcohol and obesity interact and whether the combined effects on the progression of liver injury are additive or synergistic. This review describes single as well as combined effects of alcohol and (components of) the metabolic syndrome on hepatic steatosis, inflammation and fibrosis. In addition to direct effects on the liver, the view is expanded to other organs affected by chronic alcohol consumption or the metabolic syndrome, to understand also extrahepatic pathophysiological mechanisms involved in hepatocellular injury. Undoubtedly, alcohol and the metabolic syndrome appear as a dangerous mix, and there are important synergistic effects of either condition with regard to crucial triggers of liver injury.     

Id-1 as a molecular target in therapy for breast cancer cell invasion and metastasis

Mammary epithelial cells constitutively expressing Id-1 protein are unable to differentiate, acquire the ability to proliferate, and invade the extracellular matrix. In addition, Id-1 is aberrantly over-expressed in aggressive and metastatic breast cancer cells, as well as in human breast tumor biopsies from infiltrating carcinomas, suggesting Id-1 might be an important regulator of breast cancer progression. We show that human metastatic breast cancer cells become significantly less invasive in vitro and less metastatic in vivo when Id-1 is down-regulated by stable transduction with antisense Id-1. Expression of the matrix metalloproteinase MT1-MMP is decreased in proportion to the decrease in Id-1 protein levels, representing a potential mechanism for the reduction of invasiveness. Further, to more accurately recapitulate the biology of and potential therapeutic approaches to tumor metastasis, we targeted Id-1 expression systemically in tumor-bearing mice by using a nonviral approach. We demonstrate significant reduction of both Id-1 and MT1-MMP expressions as well as the metastatic spread of 4T1 breast cancer cells in syngeneic BALB/c mice. In conclusion, our studies have identified Id-1 as a critical regulator of breast cancer progression and suggest the feasibility of developing novel therapeutic approaches to target Id-1 expression to reduce breast cancer metastasis in humans.     

Increased Serum Type IV Collagen 7-S Levels in Patients with Hepatic Metastasis

Objective: The purpose of this study was to assess scrum type IV collagen 7-S domain (IV 7-S) levels in colorectal cancer patients with hepatic metastasis and to investigate the relation between serum IV 7-S levels and type IV collagenase activities in tumor tissue. Methods: Tissue type IV collagena.se activity and serum IV 7-S were measured in 50 colorectal cancer patients without hepatic metastasis and in 26 patients with hepatic metastasis. Results: Type IV collagenase showed significantly higher activities in colorectal cancer (n = 36) than in colorectal normal mucosa (n = 36) ( p < 0.001), but significantly lower activities were shown in the hepatic metastatic tumor (n = 18) than in the primary tumor (n = 36) and normal liver tissue (n = 18) ( p < 0.001). No significant correlation was (bund between type IV collagenase activities in the tumor and serum IV 7-S levels. Colorectal cancer patients with hepatic metastasis (n = 26) had significantly higher serum IV 7-S levels than those without hepatic metastasis (n = 50) ( p < 0.001). Moreover, serum IV 7-S levels correlated significantly with hepatic metastatic tumor volume in patients with synchronous ( r = 0.719, p < 0.001, n = 26) and in patients with metachronous ( r = 0.910, p < 0.001, n = 16) hepatic metastasis. Conclusion: We suggest that serum IV 7-S levels may increase in hepatic metastasis, not by the degradation of type IV collagen in the primary and secondary tumors, but by the enhanced production of type IV collagen responsive to hepatic metastasis. The measurement of serum IV 7-S levels might be a useful tumor marker of hepatic metastasis reflecting hepatic metastatic tumor volume.     

Searching for the link; mechanisms underlying liver regeneration and recurrence of colorectal liver metastasis post partial hepatectomy

Despite excellent treatment of primary colorectal cancer, the majority of deaths occur as a result of metastasis to the liver. Recent population studies have estimated that one quarter of patients with colorectal cancer will incur synchronous or metachronous colorectal liver metastasis. However, only one quarter of these patients will be eligible for potentially curative resection. Tumor recurrence occurs in reportedly 60% of patients undergoing hepatic resection, and the majority of intrahepatic recurrence occurs within the first 6 months of surgery. The livers innate ability to restore its homeostatic size, and volume facilitates major hepatic resection that currently offers the only chance of cure to patients with extensive hepatic metastases. Experimental and clinical evidence supports the notion that following partial hepatectomy, liver regeneration (LR) paradoxically drives tumor progression and increases the risk of recurrence. It is becoming increasingly clear that the processes that drive liver organogenesis, regeneration, and tumor progression are inextricably linked. This presents a major hurdle in the management of colorectal liver metastasis and other hepatic malignancies because therapies that reduce the risk of recurrence without hampering LR are sought. The processes and pathways underlying these phenomena are multiple, complex, and cross‐communicate. In this review, we will summarize the common mechanisms contributing to both LR and tumor recurrence.     

Mechanisms in alcohol-associated carcinogenesis

This review represents an overview on some aspects of pathogenetic mechanisms in alcohol-associated carcinogenesis and is based on presentations held on the symposium "Mechanisms in alcohol-associated carcinogenesis" at the 2004 ISBRA Meeting in Heidelberg/Mannheim, Germany. The chairs were Nils Homann and Hiromasa Ishii. The presentations were (1) Genetic polymorphisms of alcohol and aldehyde dehydrogenases, mean corpuscular volume and cancer risk of the upper aerodigestive tract in Japanese by Akira Yokoyama; (2) Retinoids, alcohol and carcinogenesis by Xiang-Dong Wang; (3) Bacterial ethanol metabolism and cancer by Nils Homann; (4) The role of ethanol metabolism in alcohol-associated carcinogenesis by Helmut K. Seitz; (5) Alcohol and breast cancer: potential mechanisms by Keith W. Singletary.     

Akt2 overexpression plays a critical role in the establishment of colorectal cancer metastasis

Colorectal cancer is the second leading cause of cancer-related deaths in the United States. Understanding the distinct genetic and epigenetic changes contributing to the establishment and growth of metastatic lesions is crucial for the development of novel therapeutic strategies. In a search for key regulators of colorectal cancer metastasis establishment, we have found that the serine/threonine kinase Akt2, a known proto-oncogene, is highly expressed in late-stage colorectal cancer and metastatic tumors. Suppression of Akt2 expression in highly metastatic colorectal carcinoma cells inhibits their ability to metastasize in an experimental liver metastasis model. Overexpression of wild-type Akt1 did not restore metastatic potential in cells with downregulated Akt2, thus suggesting non-redundant roles for the individual Akt isoforms. In contrast, Akt2 overexpression in wild-type PTEN expressing SW480 colorectal cancer cells led to the formation of micrometastases; however, loss of PTEN is required for sustained formation of overt metastasis. Finally, we found that the consequence of PTEN loss and Akt2 overexpression function synergistically to promote metastasis. These results support a role for Akt2 overexpression in metastatic colorectal cancer and establish a mechanistic link between Akt2 overexpression and PTEN mutation in metastatic tumor establishment and growth. Taken together, these data suggest that Akt family members have distinct functional roles in tumor progression and that selective targeting of the PI3K/Akt2 pathway may provide a novel treatment strategy for colorectal cancer metastasis.     

Comparative study of proteome between primary cancer and hepatic metastatic tumor in colorectal cancer

AIM: To identify the differential proteins associated with colorectal cancer genesis and hepatic metastasis.METHODS: Hydrophobic protein samples were extracted from normal colorectal mucosa, primary cancer lesion and hepatic metastatic foci of colorectal cancer. With twodimensional electrophoresis and image analysis,differentially expressed protein spots were detected, and the proteins were identified by matrix assisted laser desorption/ionization-time of flight-mass spectrometry and peptide mass fingerprint analysis.RESULTS: Significant alterations of the proteins in number and expression levels were discovered in primary cancer and hepatic metastatic foci, the expression of a number of proteins was lost in 25-40 ku, but protein spots was increased in 14-21ku, compared with normal mucosa. Nine differentially expressed protein spots were identified. Three proteins expressed in normal mucosa, but lost in primary cancer and hepatic metastasis, were recognized as calmodulin, ribonuclease 6 precursor and mannosidase-α.Proapolipoprotein was expressed progressively from normal mucosa to primary cancer and hepatic metastasis. The differentially expressed protein of beta-globin was found in normal mucosa and hepatic metastatic tumor, but lost in primary cancer lesion. Cdc 42, a GTP-binding protein, was identified in hepatic metastasis. The protein spots of C4 from primary cancer, M7 and M9 from hepatic metastasis had less homology with the proteins in database.CONCLUSION: Variations of hydrophobic protein expression in colorectal cancer initiation and hepatic metastasis are significant and can be observed with two-dimensional electrophoresis. The expression of calmodulin, ribonuclease 6 precursor and mannosidase-α is lost but the expression of proapolipoprotein is enhanced which is associated with colorectal cancer genesis and hepatic metastasis. Cdc 42 and beta-globin are expressed abnormally in hepatic metastasis. Protein C4, M7 and M9 may be associated with colorectal cancer genesis and hepatic metastasis.     

Vasoactive intestinal peptide induces oxidative stress and suppresses metastatic potential in human clear cell renal cell carcinoma

Molecular mechanisms involved in progression of clear-cell renal-cell carcinomas (ccRCCs) are poorly understood. A common genetic mutation found in ccRCC is the loss of the von Hippel–Lindau (VHL) gene, which contributes to cancer progression and metastasis. We investigated VIP effects on metastatic and angiogenic factors in human VHL-null A498 ccRCC and HK2 renal cells. VIP increased adhesion but decreased expression of metalloproteinases, MMP2 and MMP9, as well as cell migration and VEGF expression and secretion in A498 but not in HK2 cells. VIP enhanced ROS levels and decreased nuclear levels of β-catenin and NFκB p50-subunit in A498 cells, suggesting neuropeptide involvement in the observed decrease of metastatic ability in clear-cell carcinoma. VIP effects in A498 cells were blocked by the VPAC_1/2-receptor antagonist JV-1-53. In conclusion, present data point to a role of VIP in preventing invasion and metastasis in ccRCCs and support its potential therapeutic usefulness in this disease.     

Epimorphin promotes human hepatocellular carcinoma invasion and metastasis through activation of focal adhesion kinase/extracellular signal-regulated kinase/matrix metalloproteinase-9 axis

The high incidence rate of hepatocellular carcinoma (HCC) is mainly the result of frequent metastasis and tumor recurrence. Unfortunately, the underlying molecular mechanisms driving HCC metastasis are still not fully understood. It has been demonstrated that tumor stroma cells contribute to primary tumor growth and metastasis. Within the HCC environment, activated hepatic stellate cells (HSCs) can release a number of molecules and enhance cancer cell proliferation and invasiveness in a paracrine manner. Here, for the first time, we demonstrate that epimorphin (EPM; also called syntaxin-2), an extracellular protein, is strongly elevated in activated HSCs within tumor stroma. We show that knockdown of EPM expression in HSCs substantially abolishes their effects on cancer cell invasion and metastasis. Ectopic expression of EPM in HCC cancer cells enhances their invasiveness; we demonstrate that the cells expressing EPM have markedly increased metastasis potential. Furthermore, EPM-mediated invasion and metastasis of cancer cells is found to require up-regulation of matrix metalloproteinase-9 (MMP-9) through the activation of focal adhesion kinase (FAK)/extracellular signal-regulated kinase (ERK) axis. CONCLUSION: Our results show that EPM, secreted by activated HSCs within HCC stroma, promotes invasion and metastasis of cancer cells by activating MMP-9 expression through the FAK-ERK pathway.     

Prevention of liver metastasis by intraperitoneal 5-FU chemotherapy in nude mice inoculated with human colon cancer cells

AIM: To prevent hepatic metastasis by regional adjuvant chemotherapy after radical surgery for colon cancer. METHODS: A nude mouse model of human colon cancer (HCC) was used to evaluate the prevention of metastasis of HCC cells following the application of early postoperative intraperitoneal (IP) high-dose 5-fluorouracil chemotherapy. RESULTS: The incidence of liver metastasis was decreased by 40%, and the mean number of metastatic liver nodules was reduced by 50.89%. Compared with controls, 5-FU 40 mg in NS 40 mL/kg IP for 2 consecutive days prolonged mean survival by 48.21%. CONCLUSION: IP is a promising and effective novel regional adjuvant chemotherapy for the prevention of liver metastasis of HCC cells after radical surgery for colon cancer.     

Analysis of the prognostic factors for liver metastasis of gastric cancer after hepatic resection: a multi-institutional study of the indications for resection

BACKGROUND/AIMS: The number of reports of hepatic resection for metastatic gastric cancer is very small. The outcome and indications of hepatic resection for metastatic gastric cancer remains unknown. METHODOLOGY: A multi-institutional study was made. Thirty-six patients who underwent a hepatic resection for liver metastasis of gastric cancer with no residual tumor were included in this study. The clinicopathological factors were examined as prognostic factors by multivariate analyses. Thirty patients had recurrence and the recurrence pattern and risk factors for extrahepatic recurrence was examined. RESULTS: The overall survival rate was 64% at 1 year, 43% at 2 years, 26% at 3 years 26% at 5 years, and 26% at 10 years after hepatectomy. Multivariate analysis showed that lymphatic invasion, venous invasion of cancer cells of primary gastric cancer and the number of the liver metastasis (> 3) were independent poor prognostic factors after hepatic resection. The most common recurrence pattern was intrahepatic recurrence in 22 patients (73%). The risk factors for extrahepatic recurrence was serosal invasion, lymph node metastasis of primary gastric cancer, stage, and curability of operation. CONCLUSIONS: Hepatic resection for liver metastasis should be attempted in case primary gastric cancer has neither lymphatic invasion nor venous invasion. The most common recurrent site was the liver. In patients with advanced gastric cancer, having neither serosal invasion nor lymph node metastasis, who underwent a less curative operation, the intra-hepatic recurrence would be expected. Thus, aggressive adjuvant chemotherapy through the hepatic artery may improve the survival after hepatectomy in these patients.     

Time to think: Selecting patients who may benefit from synchronous resection of primary pancreatic cancer and liver metastases

Pancreatic cancer remains a lethal disease and is associated with poor prognosis, particularly for patients with distant metastasis at diagnosis. Recently, Oweira reported a retrospective study that included 13233 metastatic pancreatic cancer patients from the Surveillance, Epidemiology and End Results database. They demonstrated that pancreatic cancer patients with isolated liver metastases had worse outcomes than patients with isolated lung metastases or distant nodal metastases. At present, the standard treatment for metastatic pancreatic cancer is chemotherapy. However, improvement in the safety of pancreatic surgery has led to the consideration of more aggressive surgical approaches. Schneitler reported two cases of hepatic metastatic pancreatic cancer in which negative margin(R0) resection and long survival were achieved after effective preoperative chemotherapy. In general, these two studies indicate that although pancreatic cancer patients with liver metastasis have a poor prognosis, surgical approaches may prolong survival for a few of these patients. A strategy to select hepatic metastatic pancreatic cancer patients who may benefit from surgical intervention is urgently needed.     

LKB1 inhibits lung cancer progression through lysyl oxidase and extracellular matrix remodeling

LKB1 loss-of-function mutations, observed in ～30% of human lung adenocarcinomas, contribute significantly to lung cancer malignancy progression. We show that lysyl oxidase (LOX), negatively regulated by LKB1 through mTOR-HIF-1α signaling axis, mediates lung cancer progression. Inhibition of LOX activity dramatically alleviates lung cancer malignancy progression. Up-regulated LOX expression triggers excess collagen deposition in Lkb1-deficient lung tumors, and thereafter results in enhanced cancer cell proliferation and invasiveness through activation of β1 integrin signaling. High LOX level and activity correlate with poor prognosis and metastasis. Our findings provide evidence of how LKB1 loss of function promotes lung cancer malignancy through remodeling of extracellular matrix microenvironment, and identify LOX as a potential target for disease treatment in lung cancer patients.