Aberrant TIMP-1 production in tumor-associated fibroblasts drives the selective benefits of nintedanib in lung adenocarcinoma

The fibrotic tumor microenvironment is a pivotal therapeutic target. Nintedanib, a clinically approved multikinase antifibrotic inhibitor, is effective against lung adenocarcinoma (ADC) but not squamous cell carcinoma (SCC). Previous studies have implicated the secretome of tumor-associated fibroblasts (TAFs) in the selective effects of nintedanib in ADC, but the driving factor(s) remained unidentified. Here we examined the role of tissue inhibitor of metalloproteinase-1 (TIMP-1), a tumor-promoting cytokine overproduced in ADC-TAFs. To this aim, we combined genetic approaches with in vitro and in vivo preclinical models based on patient-derived TAFs. Nintedanib reduced TIMP-1 production more efficiently in ADC-TAFs than SCC-TAFs through a SMAD3-dependent mechanism. Cell culture experiments indicated that silencing TIMP1 in ADC-TAFs abolished the therapeutic effects of nintedanib on cancer cell growth and invasion, which were otherwise enhanced by the TAF secretome. Consistently, co-injecting ADC cells with TIMP1-knockdown ADC-TAFs into immunocompromised mice elicited a less effective reduction of tumor growth and invasion under nintedanib treatment compared to tumors bearing unmodified fibroblasts. Our results unveil a key mechanism underlying the selective mode of action of nintedanib in ADC based on the excessive production of TIMP-1 in ADC-TAFs. We further pinpoint reduced SMAD3 expression and consequent limited TIMP-1 production in SCC-TAFs as key for the resistance of SCC to nintedanib. These observations strongly support the emerging role of TIMP-1 as a critical regulator of therapy response in solid tumors.

Abstract 4597: TIMP1 is a major contributor of the angiogenic priming of tumor associated fibroblasts in lung adenocarcinoma

Background: Lung adenocarcinoma (ADC) and squamous cell carcinoma (SCC) are the most common histologic subtypes in lung cancer. Intriguingly, ADC and SCC exhibit distinct responses to the multi-tyrosine kinase inhibitor nintedanib and other antiangiogenic drugs, suggesting that angiogenesis may depend on the histologic subtype in lung cancer. In addition, tumor-associated fibroblasts (TAFs) are known regulators of angiogenesis, and we have recently reported that TAFs exhibit enhanced fibrosis and response to nintedanib in ADC compared to SCC, owing to the stronger epigenetic repression of SMAD3 in SCC-TAFs caused by excessive exposure to cigarette smoke particles. However, how the histotype-dependent fibrotic phenotype in TAFs impacts their pro-angiogenic functions remains unknown.

Methods: A panel of angiogenesis markers was assessed in patient samples using publicly available databases. The pro-angiogenic function of the conditioned medium of TAFs from ADC and SCC patients pre-activated with TGF-β1 was analyzed in vitro using migration and network formation assays of endothelial cells. The secretion of pro-angiogenic factors in TGF-β1-activated TAFs was analyzed using an angiogenesis antibody blot array. Selected factors were functionally validated in vitro and in vivo using genetic models.

Results: All angiogenesis markers were consistently upregulated in ADC compared to SCC concomitantly with a lower necrosis in ADC, unveiling a larger angiogenesis in ADC. We also observed that the conditioned medium of TGF-β1-activated TAFs elicited a larger endothelial cell network formation and migration in ADC than SCC, revealing that ADC-TAFs exhibit enhanced angiogenesis. Our immunoblot array analysis identified a subset of pro-angiogenic factors that were selectively overexpressed in ADC-TAFs compared to SCC-TAFs, including TIMP-1. Notably, TIMP-1 overexpression in ADC-TAFs was SMAD3-dependent and knocking down TIMP-1 by siRNA in ADC-TAFs impaired angiogenesis in vitro and in tumor xenografts in vivo.

Conclusions: Our results reveal a larger angiogenesis in ADC compared to SCC, and implicate the TGF-β1/SMAD3/TIMP-1 pathway in the enhanced angiogenesis of ADC-TAFs. Our findings identify a biological process underlying the poor response of SCC to antiangiogenic therapies like nintedanib, and provide a rationale for the earlier metastasis of ADC patients compared to SCC patients based on the enhanced pro-angiogenic role of ADC-TAFs.

Citation Format: Natalia Isabel Diaz Valdivia, Paula Duch, Rafael Ikemori, Eduard Monso, Noemi Reguart, Jordi Alcaraz. TIMP1 is a major contributor of the angiogenic priming of tumor associated fibroblasts in lung adenocarcinoma. [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 4597.

Abstract 2356: Aberrant TIMP-1 secretion by tumor-associated fibroblasts is a major contributor to the selective positive response to nintedanib in lung adenocarcinoma

Adenocarcinoma (ADC) and Squamous Cell Carcinoma (SCC) are the most frequent histologic subtypes of lung cancer, and both are rich in activated/myofibroblast-like tumor-associated fibroblasts (TAFs). Nintedanib is a potent antifibrotic drug that targets the tumor stroma and is clinically approved to treat advanced lung ADC patients owing to the survival benefits observed in the LUME-1 clinical trial in ADC but not SCC patients. Although the mechanism underlying the ADC-selective therapeutic effects of nintedanib remained poorly understood, we have previously reported that nintedanib abrogates the pro-tumoral traits of the secretome of ADC-TAFs but not SCC-TAFs, suggesting that secreted factor(s) in ADC-TAFs may be implicated. In addition, we recently unveiled an ADC-specific tumor-promoting crosstalk between TAFs and cancer cells driven by TIMP-1 and CD63, whereas others have shown that TIMP-1 is a molecular target of nintedanib. However, it remains unknown if TIMP-1 is involved in the ADC-selective benefits of nintedanib. To address this question, we used patient-derived TAFs obtained with the patient’s informed consent and using protocols approved by the Ethics Committee of the Hospital Clinic. We treated TGF-β1-activated ADC-TAFs and SCC-TAFs with nintedanib and determined the content of TIMP-1 in their conditioned medium by ELISA. Moreover, we used cell-based functional assays and tumor xenografts after knocking-down TIMP-1 in TAFs by siRNA to examine how silencing TIMP-1 altered their response to nintedanib. By analyzing TCGA data and the human protein atlas, we found that TIMP-1 is consistently upregulated in ADC compared to SCC tumors both at the mRNA and protein levels. Moreover, TCGA data revealed that TIMP-1 is increased in tumors compared to paired control tissue in ADC but not SCC. In culture, we observed that TIMP-1 secretion was higher in ADC-TAFs than SCC-TAFs, and that this secretion was downregulated by nintedanib to a larger extent in ADC-TAFs compared to SCC-TAFs. In vivo analyses revealed that ADC cells co-injected with fibroblasts silenced for TIMP-1 as in SCC-TAFs into immunocompromised mice exhibited a less invasive growth pattern compared to tumors bearing control fibroblasts. In addition, we observed that the inhibition of the pro-tumoral secretome of ADC-TAFs elicited by nintedanib was abrogated upon knocking-down TIMP-1 in TAFs both in vitro and in vivo. Collectively, these results reveal that the high secretion of TIMP-1 in ADC-TAFs render them more responsive to nintedanib, whereas the low TIMP-1 secretion of SCC-TAFs may be a major contributor to the selective resistance of SCC patients to nintedanib. Moreover, our results identify TIMP-1 as a promising predictive biomarker of nintedanib responses.

Citation Format: Paula Duch, Natalia Díaz-Valdivia, Marta Gabasa, Rafael Ikemori, Frank Hilberg, Noemí Reguart, Derek Radisky, Jordi Alcaraz. Aberrant TIMP-1 secretion by tumor-associated fibroblasts is a major contributor to the selective positive response to nintedanib in lung adenocarcinoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 2356.

Aberrant TIMP-1 overexpression in tumor-associated fibroblasts drives tumor progression through CD63 in lung adenocarcinoma

Tissue inhibitor of metalloproteinase-1 (TIMP-1) is an important regulator of extracellular matrix turnover that has been traditionally regarded as a potential tumor suppressor owing to its inhibitory effects of matrix metalloproteinases. Intriguingly, this interpretation has been challenged by the consistent observation that increased expression of TIMP-1 is associated with poor prognosis in virtually all cancer types including lung cancer, supporting a tumor-promoting function. However, how TIMP-1 is dysregulated within the tumor microenvironment and how it drives tumor progression in lung cancer is poorly understood. We analyzed the expression of TIMP-1 and its cell surface receptor CD63 in two major lung cancer subtypes: lung adenocarcinoma (ADC) and squamous cell carcinoma (SCC), and defined the tumor-promoting effects of their interaction. We found that TIMP-1 is aberrantly overexpressed in tumor-associated fibroblasts (TAFs) in ADC compared to SCC. Mechanistically, TIMP-1 overexpression was mediated by the selective hyperactivity of the pro-fibrotic TGF-β1/SMAD3 pathway in ADC-TAFs. Likewise, CD63 was upregulated in ADC compared to SCC cells. Genetic analyses revealed that TIMP-1 secreted by TGF-β1-activated ADC-TAFs is both necessary and sufficient to enhance growth and invasion of ADC cancer cells in culture, and that tumor cell expression of CD63 was required for these effects. Consistently, in vivo analyses revealed that ADC cells co-injected with fibroblasts with reduced SMAD3 or TIMP-1 expression into immunocompromised mice attenuated tumor aggressiveness compared to tumors bearing parental fibroblasts. We also found that high TIMP1 and CD63 mRNA levels combined define a stronger prognostic biomarker than TIMP1 alone. Our results identify an excessive stromal TIMP-1 within the tumor microenvironment selectively in lung ADC, and implicate it in a novel tumor-promoting TAF-carcinoma crosstalk, thereby pointing to TIMP-1/CD63 interaction as a novel therapeutic target in lung cancer.

Abstract 2515: MMP1 and TGF-β1 cooperate to drive tumor progression in large cell carcinoma of the lung through fibroblast senescence

Large cell carcinoma (LCC) is an aggressive lung cancer subtype with poor prognosis and no targeted therapies. We previously reported that tumor-associated fibroblasts (TAFs) derived from LCC tumors exhibit premature senescence, and coculture of pulmonary fibroblasts with LCC cell lines selectively induces fibroblast senescence, which in turn drives LCC cell growth and invasion. Here we report that MMP1 is overexpressed specifically in LCC cell lines. Notably, silencing MMP1 expression in LCC cancer cell lines using shRNA revealed that MMP1 expression by LCC cells is necessary for induction of fibroblast senescence in coculture experiments with normal pulmonary fibroblasts, as revealed by the analysis of a panel of standard senescence markers, including β-galactosidase (SA-βgal) staining, permanent growth arrest and expression of senescence-associated secretory factors. Injecting control (shScr) or shMMP1 LCC cells into immunodeficient nude mice revealed that tumor growth, tumor take and cancer cell dissemination to the lung were reduced in shMMP1 H460 tumors compared to control tumors. We also observed fewer senescent fibroblasts in tumors from shMMP1 H460 cells using Sentragor staining, which allows identification of senescent cells in paraffin embedded tissues. Moreover, we found that recombinant active MMP1 in combination with TGF-β1 were sufficient to induce normal fibroblast senescence. In terms of the potential underlying mechanisms, treatment with the antioxidant n-acetyl cysteine (NAC) significantly attenuated the increase in SA-βgal+ fibroblasts elicited by co-stimulation with rMMP1 and TGF-β1, and its corresponding conditioned medium elicited a significantly lower growth and invasion in LCC cancer cells, revealing the oxidative stress implication in fibroblast senescence induction and associated pro-tumorigenic secretome. In summary, our results establish a new role for MMP1 in cancer and support that LCC cells elicit a tumor-supporting niche through the aberrant secretion of MMP1 and TGF-β1 to induce senescence in adjacent fibroblasts. Furthermore, we implicate oxidative stress in MMP1/TGF-β1-induced TAF senescence and support a novel therapeutic strategy in LCC based on targeting senescent TAFs.

Citation Format: Marta Gabasa, Evette S. Radisky, Rafael Ikemori, Giulia Bertolini, Marselina Arshakyan, Alexandra Hockla, Paula Duch, Ornella Rondinone, Alejandro Llorente, Maria Maqueda, Alexandre Perera, Noemí Reguart, Luca Roz, Derek C. Radisky, Jordi Alcaraz. MMP1 and TGF-β1 cooperate to drive tumor progression in large cell carcinoma of the lung through fibroblast senescence [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 2515.

Abstract 3167: Stromal TIMP-1 drives tumor progression in lung adenocarcinoma through CD63 interaction

The two most common lung cancer subtypes are adenocarcinoma (ADC) and squamous cell carcinoma (SCC). Even though both subtypes are epithelial in origin, it is now clear that tumor associated fibroblasts (TAFs) are key regulators of tumor progression and response to therapies. Nintedanib is an antifibrotic drug that targets the tumor stroma and has been clinically approved to treat lung ADC patients owing to the therapeutic benefits exhibited by this drug selectively in ADC (but not in SCC) in the LUME-1 cinical trial. We have implicated recently both ADC-TAFs and ADC cancer cells in the selective effects of nintedanib in ADC, since this drug reduced the growth and invasion induction elicited by the secretome of TGF-β-activated ADC-TAFs on a panel of ADC cells, whereas such reduction was not observed in SCC-TAFs. However, the key molecules involved in the aberrant TAF-carcinoma crosstalk in ADC remain unknown. TIMP-1 is a multifunctional protein that has been associated with poor prognosis in lung cancer and is downregulated by nintedanib in a bleomycin model of pulmonary fibrosis. Our preliminary results revealed that the TIMP-1 receptor CD63 is overexpressed in ADC patients compared to SCC. Therefore, our working hypothesis was that nintedanib reduces ADC cells growth and invasion by abrogating the TAF-carcinoma crosstalk driven by TIMP-1 and CD63.To test this hypothesis, we used primary TAFs obtained with the patient informed consent, and using protocols approved by the Ethics Committee of the Hospital Clinic. TGF-β1-activated ADC-TAFs and SCC-TAFs were treated with nintedanib, and their secreted TIMP-1 was determined by ELISA. Two high-CD63 cell lines (H1437 and H23) were used in some experiments, and siRNA was used to knock-down either TIMP-1 in TAFs or CD63 in cancer cellsOur in vitro results showed that the secretion of TIMP-1 was significantly larger in ADC-TAFs compared to SCC-TAFs. Likewise, nintedanib elicited a higher TIMP-1 downregulation in ADC-TAFs compared SCC-TAFs. Of note, TIMP-1 and CD63 were both implicated in the pro-tumorigenic crosstalk, since knocking-down TIMP-1 in ADC-TAFs or CD63 in ADC cells was sufficient to abrogate the growth and invasion enhancement elicited by the secretome of TAFs. Moreover, CD63 was necessary to enhance the invasion of ADC cells upon stimulation with recombinant TIMP-1. In addition, we found that knocking-down TIMP-1 in ADC-TAFs was sufficient to compromise the inhibitory effects of nintedanib on the growth and invasion enhancement elicited by the secretome of TAFs on ADC cells. Collectively, our results support a novel TAF-carcinoma crosstalk driven by TIMP-1 and CD63 in lung ADC, and support that such heterotypic crosstalk may underlie the aberrant tumor-promoting effects of ADC-TAFs that are selectively downregulated by nintedanib.

Citation Format: Paula Duch, Natalia Díaz-Valdivia, Marta Gabasa, Rafael Ikemori, Marselina Arshakyan, Frank Hillberg, Noemí Reguart, Derek Radisky, Jordi Alcaraz. Stromal TIMP-1 drives tumor progression in lung adenocarcinoma through CD63 interaction [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 3167.

MMP1 drives tumor progression in large cell carcinoma of the lung through fibroblast senescence

Large cell carcinoma (LCC) is a rare and aggressive lung cancer subtype with poor prognosis and no targeted therapies. Tumor-associated fibroblasts (TAFs) derived from LCC tumors exhibit premature senescence, and coculture of pulmonary fibroblasts with LCC cell lines selectively induces fibroblast senescence, which in turn drives LCC cell growth and invasion. Here we identify MMP1 as overexpressed specifically in LCC cell lines, and we show that expression of MMP1 by LCC cells is necessary for induction of fibroblast senescence and consequent tumor promotion in both cell culture and mouse models. We also show that MMP1, in combination with TGF-β1, is sufficient to induce fibroblast senescence and consequent LCC promotion. Furthermore, we implicate PAR-1 and oxidative stress in MMP1/TGF-β1-induced TAF senescence. Our results establish an entirely new role for MMP1 in cancer, and support a novel therapeutic strategy in LCC based on targeting senescent TAFs.

Abstract 5091: TIMP-1 in tumor-associated fibroblasts drives tumor progression in lung adenocarcinoma through CD63 interaction

Tumor associated fibroblasts (TAFs) are important regulators of tumor growth and resistance to therapies. We have recently shown that lung TAFs in vitro respond to the antifibrotic drug nintedanib in adenocarcinoma (ADC) but not squamous cell carcinoma (SCC). We also showed that the tumor-promoting effects of TAFs are driven by different mechanisms in ADC and SCC, which remain to be elucidated. Tissue inhibitor of metalloproteinases 1 (TIMP-1) has been associated with poor prognosis in lung cancer, its expression is downregulated by nintedanib, and our preliminary results reveal that its putative receptor, CD63, is overexpressed in ADC patients compared to SCC, supporting a selective crosstalk between TAFs and cancer cells in ADC through TIMP-1 and CD63. The aim of this study was to test this hypothesis using in vitro preclinical models. Primary fibroblasts were obtained with the patient informed consent, and using protocols approved by the Ethics Committee of the Hospital Clinic. ADC-TAFs and SCC-TAFs were stimulated with TGF-β1 in the presence or absence of nintedanib, and the TIMP-1 content in their conditioned medium was determined by ELISA. TIMP-1 was knocked-down in ADC-TAFs by siRNA, and the corresponding conditioned medium was used to stimulate growth and invasion of the high-CD63 ADC cell line, H1437. Likewise, CD63 expression in H1437 cells was reduced by siRNA. Our in vitro results showed that TIMP-1 secretion induced by TGF-β1 is significantly larger in ADC-TAFs compared to SCC-TAFs. Likewise, nintedanib elicited a higher downregulation of secreted TIMP-1 in ADC-TAFs compared to SCC-TAFs. Of note, TIMP-1 from ADC-TAFs was necessary to induce growth and invasion of H1437 cells. Likewise, knocking-down CD63 in H1437 ADC cells was sufficient to reduce the growth and invasion elicited by the conditioned medium of TGF-β1 activated ADC-TAFs. Collectively, our results unveil a novel stroma-carcinoma crosstalk driven by TIMP-1 and CD63 selectively in lung ADC, and support that such heterotypic crosstalk may underlie the aberrant tumor-promoting effects of ADC-TAFs that are selectively downregulated by nintedanib.

Citation Format: Paula Duch, Marta Gabasa, Rafael Ikemori, Marselina Arshakyan, Frank Hillberg, Noemí Reguart, Derek Radisky, Jordi Alcaraz. TIMP-1 in tumor-associated fibroblasts drives tumor progression in lung adenocarcinoma through CD63 interaction [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 5091.

Abstract 2982: Unraveling the antifibrotic mode of action of nintedanib against the TGF-β pathway in tumor-associated fibroblasts in non-small cell lung cancer

Non-small cell lung cancer (NSCLC) is the leading cause of cancer related death, and its major histotypes are lung adenocarcinoma (ADC) and squamous cell carcinoma (SCC). Nintedanib (Vargatef) is a multi-tyrosine kinase inhibitor of VEGF, FGF and PDGF receptors that has been approved as second-line treatment of advanced lung adenocarcinoma patients, owing to the positive therapeutic effects reported selectively on ADC but not SCC patients in the LUME-1 clinical trial. Nintedanib has been also approved to treat idiopathic pulmonary fibrosis due to its antifibrotic effects reported in the INPULSIS trial. Of note, we recently reported that tumor fibrosis is larger in ADC than SCC due to the stronger epigenetic repression of the pro-fibrotic TGF-β transcription factor SMAD3 in tumor-associated fibroblasts (TAFs) in SCC compared to ADC. Moreover, we also showed that nintedanib elicits a larger inhibition of TGF-β-induced fibrosis in ADC-TAFs compared to SCC-TAFs. However, the detailed antifibrotic mechanisms of nintedanib on the TGF-β1 pathway remain poorly understood. TGF-β1 signaling begins with its binding to type II TGF-β receptor, which phosphorylates type I TGF-β receptor ALK5, that subsequently phosphorylates SMAD2 and SMAD3, upon which they form heterotrimeric complexes with the co-factor SMAD4 that translocate to the nucleus to regulate gene expression. We found that nintedanib markedly inhibited both the activation of SMAD2 and SMAD3 as well as the increase in nuclear SMAD4 in response to TGF-β1 in pulmonary fibroblasts, thereby supporting that ALK5 may be an off-target of nintedanib. To examine this possibility, we performed a time-course analysis of phospho-ALK5 (pALK5) and pSMAD3 in fibroblasts in response to TGF-β1 with or without nintedanib. As expected, TGF-β1 elicited a peak in pALK5 before that of pSMAD3. Moreover, nintedanib downregulated pALK5 but not total ALK5, supporting that ALK5 is an unintended target of this drug. In addition, we examined the expression of total and phospho-Erk1/2 in the same samples, since Erk1/2 has been previously reported as a regulator of cellular responses to TGF-β. TGF-β1 elicited a peak in pErk1/2 within the same time-window than pSMAD3, which is consistent with previous observations on non-canonical TGF-β signaling. Interestingly, nintedanib abrogated both total and pErk1/2 expression in a time-dependent fashion. These results support that the antifibrotic effects of nintedanib may be mediated through their inhibition of the pro-fibrotic transcription factor SMAD3 as well as the downregulation of Erk1/2. In addition, our results support that Erk1/2 may be implicated in the limited responses of SCC-TAFs to nintedanib, since we previously showed that SCC-TAFs exhibit an enhanced activity of Erk1/2 compared to ADC-TAFs.

Citation Format: Rafael Ikemori, Marta Gabasa, Paula Duch, Frank Hilberg, Noemí Reguart, Jordi Alcaraz. Unraveling the antifibrotic mode of action of nintedanib against the TGF-β pathway in tumor-associated fibroblasts in non-small cell lung cancer [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 2982.

Epigenetic SMAD3 Repression in Tumor-Associated Fibroblasts Impairs Fibrosis and Response to the Antifibrotic Drug Nintedanib in Lung Squamous Cell Carcinoma

The tumor-promoting fibrotic stroma rich in tumor-associated fibroblasts (TAF) is drawing increased therapeutic attention. Intriguingly, a trial with the antifibrotic drug nintedanib in non-small cell lung cancer reported clinical benefits in adenocarcinoma (ADC) but not squamous cell carcinoma (SCC), even though the stroma is fibrotic in both histotypes. Likewise, we reported that nintedanib inhibited the tumor-promoting fibrotic phenotype of TAFs selectively in ADC. Here we show that tumor fibrosis is actually higher in ADC-TAFs than SCC-TAFs in vitro and patient samples. Mechanistically, the reduced fibrosis and nintedanib response of SCC-TAFs was associated with increased promoter methylation of the profibrotic TGFβ transcription factor SMAD3 compared with ADC-TAFs, which elicited a compensatory increase in TGFβ1/SMAD2 activation. Consistently, forcing global DNA demethylation of SCC-TAFs with 5-AZA rescued TGFβ1/SMAD3 activation, whereas genetic downregulation of SMAD3 in ADC-TAFs and control fibroblasts increased TGFβ1/SMAD2 activation, and reduced their fibrotic phenotype and antitumor responses to nintedanib in vitro and in vivo. Our results also support that smoking and/or the anatomic location of SCC in the proximal airways, which are more exposed to cigarette smoke particles, may prime SCC-TAFs to stronger SMAD3 epigenetic repression, because cigarette smoke condensate selectively increased SMAD3 promoter methylation. Our results unveil that the histotype-specific regulation of tumor fibrosis in lung cancer is mediated through differential SMAD3 promoter methylation in TAFs and provide new mechanistic insights on the selective poor response of SCC-TAFs to nintedanib. Moreover, our findings support that patients with ADC may be more responsive to antifibrotic drugs targeting their stromal TGFβ1/SMAD3 activation. SIGNIFICANCE: This study implicates the selective epigenetic repression of SMAD3 in SCC-TAFs in the clinical failure of nintedanib in SCC and supports that patients with ADC may benefit from antifibrotic drugs targeting stromal TGFβ1/SMAD3.

Abstract 1225: Aberrant SMAD3 signaling in tumor-associated fibroblasts modulates fibrosis and response to the anti-fibrotic drug nintedanib in non-small cell lung cancer

A hallmark of non-small cell lung cancer (NSCLC) is a fibrotic/desmoplastic stroma rich in activated fibroblasts, which are critical regulators of cancer progression, response to therapies and radiotherapy resistance. Paradoxically, we recently reported that the important pro-fibrotic TGF-β transcription factor SMAD3 was epigenetically down-regulated through promoter hypermethylation in tumor associated fibroblasts (TAFs) from NSCLC patients compared to patient-matched control fibroblasts. In addition, we reported that the clinically approved antifibrotic drug nintedanib elicited a stronger inhibition of both the fibrotic phenotype and its associated tumor-promoting effects in TAFs from adenocarcinoma (ADC) patients compared to squamous cell carcinoma (SCC) patients upon TGF-β1 stimulation in vitro, which was consistent with the selective therapeutic response to nintedanib observed in a clinical trial in ADC (but not SCC) patients. Altogether, these previous results suggest that TGF-β1 signaling may be altered in lung TAFs, and that such alteration may depend on their histologic subtype. In this study we addressed these questions by determining the expression and activity of SMAD3 and its closely related homologue SMAD2 in patient-derived TAFs and paired control fibroblasts, and by dissecting their potential contribution to the differential therapeutic responses to nintedanib observed in ADC and SCC. In vitro studies revealed a marked SMAD3 epigenetic repression through promoter hypermethylation, a low pSMAD3/pSMAD2 ratio and a limited fibrotic phenotype selectively in SCC-TAFs. In contrast, ADC-TAFs overexpressed a panel of fibrotic markers upon TGF-β1 stimulation concomitantly with a high pSMAD3/pSMAD2 ratio and a limited SMAD3 promoter methylation. Histologic analysis of a large patient cohort (112 ADC, 96 SCC) confirmed that the extent of fibrosis is larger in ADC than SCC patients. In addition, knocking-down SMAD3 in ADC-TAFs was sufficient to reduce the antifibrotic and antigrowth effects of nintedanib in vitro and in tumor xenografts in vivo. On the other hand, long-term exposure of pulmonary fibroblasts to cigarette smoke condensate was sufficient to hypermethylate the SMAD3 promoter. Since SCC and ADC tumors typically arise in the upper airways and distal pulmonary sites, respectively, it is conceivable that fibroblasts might be more exposed to the smoking epigenetic effects on SMAD3 in SCC. In summary, we report for the first time that tumor fibrosis is higher in ADC than SCC patients, in association with a selective therapeutic response to the antifibrotic drug nintedanib in the former, and identify the subtype-specific extent of SMAD3 epigenetic repression in TAFs and the subsequent aberrant SMAD3/SMAD2 imbalance as major regulatory mechanisms of tumor fibrosis and response to nintedanib in NSCLC.

Citation Format: Rafael Ikemori, Marta Gabasa, Miguel Vizoso, Paula Duch, Sebastian Moran, Sabrina Gea-Sorli, Paloma Bragado, Toni Jauset, Manel Esteller, Laura Soucek, Eduard Monsó, Víctor Peinado, Cristina Fillat, Frank Hilberg, Noemí Reguart, Jordi Alcaraz. Aberrant SMAD3 signaling in tumor-associated fibroblasts modulates fibrosis and response to the anti-fibrotic drug nintedanib in non-small cell lung cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 1225.

Abrogation of myofibroblast activities in metastasis and fibrosis by methyltransferase inhibition

Myofibroblasts are a population of highly contractile fibroblasts that express and require the activity of the transcription factor Snail1. Cancer-associated fibroblasts (CAFs) correlate with low survival of cancer patients when present in the stroma of primary tumors. Remarkably, the presence of myofibroblastic CAFs (which express Snail1) creates mechanical properties in the tumor microenvironment that support metastasis. However, therapeutic blockage of fibroblast activity in patients with cancer is a double-edged sword, as normal fibroblast activities often restrict tumor cell invasion. We used fibroblasts depleted of Snail1 or protein arginine methyltransferases 1 and 4 (PRMT1/-4) to identify specific epigenetic modifications induced by TGFβ/Snail1. Furthermore, we analyzed the in vivo efficiency of methyltransferase inhibitors using mouse models of wound healing and metastasis, as well as fibroblasts isolated from patients with idiopathic pulmonary fibrosis (IPF). Mechanistically, TGFβ-induced Snail1 promotes the epigenetic mark of asymmetrically dimethylated arginine. Critically, we found that inhibitors of methyltransferases prevent myofibroblast activity (but not regular fibroblast activity) in the extracellular matrix, both in cell culture and in vivo. In a mouse breast cancer model, the inhibitor sinefungin reduces both the myofibroblast activity in the tumor stroma and the metastatic burden in the lung. Two distinct inhibitors effectively blocked the exacerbated myofibroblast activity of patient-derived IPF fibroblasts. Our data reveal epigenetic regulation of myofibroblast transdifferentiation in both wound healing and in disease (fibrosis and breast cancer). Thus, methyltransferase inhibitors are good candidates as therapeutic reagents for these diseases.

Early Career Members at the ERS Lung Science Conference: cell-matrix interactions in lung disease and regeneration: Early career forum

.@EarlyCareerERS looks back on #LSC2018 http://ow.ly/6hjS30jB6P9.

Epithelial contribution to the profibrotic stiff microenvironment and myofibroblast population in lung fibrosis

The contribution of epithelial-to-mesenchymal transition (EMT) to the profibrotic stiff microenvironment and myofibroblast accumulation in pulmonary fibrosis remains unclear. We examined EMT-competent lung epithelial cells and lung fibroblasts from control (fibrosis-free) donors or patients with idiopathic pulmonary fibrosis (IPF), which is a very aggressive fibrotic disorder. Cells were cultured on profibrotic conditions including stiff substrata and TGF-β1, and analyzed in terms of morphology, stiffness, and expression of EMT/myofibroblast markers and fibrillar collagens. All fibroblasts acquired a robust myofibroblast phenotype on TGF-β1 stimulation. Yet IPF myofibroblasts exhibited higher stiffness and expression of fibrillar collagens than control fibroblasts, concomitantly with enhanced FAKY397 activity. FAK inhibition was sufficient to decrease fibroblast stiffness and collagen expression, supporting that FAKY397 hyperactivation may underlie the aberrant mechanobiology of IPF fibroblasts. In contrast, cells undergoing EMT failed to reach the values exhibited by IPF myofibroblasts in all parameters examined. Likewise, EMT could be distinguished from nonactivated control fibroblasts, suggesting that EMT does not elicit myofibroblast precursors either. Our data suggest that EMT does not contribute directly to the myofibroblast population, and may contribute to the stiff fibrotic microenvironment through their own stiffness but not their collagen expression. Our results also support that targeting FAKY397 may rescue normal mechanobiology in IPF.

Dysregulated Collagen Homeostasis by Matrix Stiffening and TGF-β1 in Fibroblasts from Idiopathic Pulmonary Fibrosis Patients: Role of FAK/Akt

Idiopathic pulmonary fibrosis (IPF) is an aggressive disease in which normal lung parenchyma is replaced by a stiff dysfunctional scar rich in activated fibroblasts and collagen-I. We examined how the mechanochemical pro-fibrotic microenvironment provided by matrix stiffening and TGF-β1 cooperates in the transcriptional control of collagen homeostasis in normal and fibrotic conditions. For this purpose we cultured fibroblasts from IPF patients or control donors on hydrogels with tunable elasticity, including 3D collagen-I gels and 2D polyacrylamide (PAA) gels. We found that TGF-β1 consistently increased COL1A1 while decreasing MMP1 mRNA levels in hydrogels exhibiting pre-fibrotic or fibrotic-like rigidities concomitantly with an enhanced activation of the FAK/Akt pathway, whereas FAK depletion was sufficient to abrogate these effects. We also demonstrate a synergy between matrix stiffening and TGF-β1 that was positive for COL1A1 and negative for MMP1. Remarkably, the COL1A1 expression upregulation elicited by TGF-β1 alone or synergistically with matrix stiffening were higher in IPF-fibroblasts compared to control fibroblasts in association with larger FAK and Akt activities in the former cells. These findings provide new insights on how matrix stiffening and TGF-β1 cooperate to elicit excessive collagen-I deposition in IPF, and support a major role of the FAK/Akt pathway in this cooperation.

Risk factors for reintervention after surgery for perforated gastroduodenal ulcer

Background

Perforated gastroduodenal ulcer carries a high mortality rate. Need for reintervention after surgical repair is associated with worse outcome, but knowledge on risk factors for reintervention is limited. The aim was to identify prognostic risk factors for reintervention after perforated gastroduodenal ulcer in a nationwide cohort.

Methods

All patients treated surgically for perforated gastroduodenal ulcer in Denmark between 2003 and 2014 were included using data from the Danish Clinical Register of Emergency Surgery. Potential risk factors for reintervention were assessed, and their crude and adjusted associations calculated by the competing risks subdistribution hazards approach.

Results

A total of 4086 patients underwent surgery for perforated gastroduodenal ulcer during the study interval. Median age was 71·1 (i.q.r. 59·6–81·0) years and the overall 90-day mortality rate was 30·8 per cent (1258 of 4086). Independent risk factors for reintervention were: male sex (adjusted hazard ratio (HR) 1·46, 95 per cent c.i. 1·20 to 1·78), in-hospital perforation (adjusted HR 1·36, 1·11 to 1·68), high BMI (adjusted HR 1·49, 1·10 to 2·01), high ASA physical status grade (adjusted HR 1·54, 1·23 to 1·94), shock on admission (adjusted HR 1·40, 1·13 to 1·74), surgical delay (adjusted HR 1·07, 1·02 to 1·14) and other co-morbidity (adjusted HR 1·24, 1·02 to 1·51). Preadmission use of steroids (adjusted HR 0·59, 0·41 to 0·84) and age above 70 years (adjusted HR 0·72, 0·59 to 0·89) were associated with a reduced risk of reoperation.

Conclusion

Obese men with coexisting diseases and high disease severity who have surgery for gastroduodenal perforation are at increased risk of reoperation.

Pulmonary toxicity following exposure to a tile coating product containing alkylsiloxanes. A clinical and toxicological evaluation

CONTEXT

Coating products are widely used for making surfaces water and dirt repellent. However, on several occasions the use of these products has been associated with lung toxicity.

OBJECTIVE

In the present study, we evaluated the toxic effects of an aerosolized tile-coating product.

METHODS

Thirty-nine persons, who reported respiratory and systemic symptoms following exposure to the tile-coating product, were clinically examined. The product was analysed chemically and furthermore, the exposure scenario was reconstructed using a climate chamber and the toxicological properties of the product were studied using in vivo and by in vitro surfactometry.

RESULTS

The symptoms developed within few hours and included coughing, tachypnoea, chest pain, general malaise and fever. The physical examination revealed perihilar lung infiltrates on chest radiograph and reduced blood oxygen saturation. The acute symptoms resolved gradually within 1-3 days and no delayed symptoms were observed. By means of mass spectrometry and X-ray spectroscopy, it was shown that the product contained non-fluorinated alkylsiloxanes. The exposure conditions in the supermarket were reconstructed under controlled conditions in a climate chamber and particle and gas exposure levels were monitored over time allowing estimation of human exposure levels. Mice exposed to the product developed symptoms of acute pulmonary toxicity in a concentration-and time-dependent manner. The symptoms of acute pulmonary toxicity likely resulted from inhibition of the pulmonary surfactant function as demonstrated by in vitro surfactometry. Among these patients only a partial association between the level of exposure and the degree of respiratory symptoms was observed, which could be because of a high inter-individual difference in sensitivity and time-dependent changes in the chemical composition of the aerosol.

CONCLUSION

Workers need to cautiously apply surface coating products because the contents can be highly toxic through inhalation, and the aerosols can disperse to locations remote from the worksite and affect bystanders.