HTLV-I associated bronchioloalveolar disorder (HABA): disease concept and differential diagnosis of an unsolved disease entity.

INTRODUCTION: Human T-cell leukemia virus type 1 (HTLV-I) associated bronchioloalveolar disorder (HABA) is a chronic and progressive bronchiolar/alveolar disorder related to HTLV-1 infection. Clinical knowledge and guidance are lacking for the diagnosis and management of this condition. AREAS COVERED: This work aimed to review the latest information and challenges regarding HABA diagnosis and treatment. EXPERT OPINION: HABA is an immune-mediated state induced by HTLV-1. For diagnosis of HABA, other infectious diseases and pulmonary infiltration of adult T-cell leukemia should be excluded by investigations such as computed tomography (CT), transbronchial biopsy, and bronchoalveolar lavage fluid (BALF) analysis. Typical CT findings in HABA include diffuse panbronchiolitis-like or bronchiectasis patterns, whereas cases with other abnormalities, including interstitial pneumonia, have also been reported. A high rate of polyclonal CD4+ and CD25+ lymphocytes is detected in BALF of patients with HABA, reflecting the infiltration of HTLV-1 infected T-cells in the lung. Current treatment options are not HABA specific, and include corticosteroids, macrolide antibiotics, and pirfenidone. Mitigation of the adverse effects of HTLV-1 infection requires the establishment of diagnostic criteria for the disease, screening programs for HABA in HTLV-1 infected individuals, and the development of effective disease treatment strategies.

Successful continuous nivolumab therapy for metastatic non-small cell lung cancer after local treatment of oligometastatic lesions.

The patient in this report was a 57-year-old man with metastatic non-small cell lung cancer (NSCLC). After no response to two lines of systemic chemotherapy, he was treated with nivolumab as third-line therapy, which resulted in a partial response. After 17 months of nivolumab treatment, he developed bone metastasis in his left femur which was treated with radiation therapy. Nivolumab was restarted after radiation therapy. Four months after radiation therapy, he developed another metastatic lesion in the small intestine which was surgically resected. Because there were no recurrent NSCLC lesions after surgical resection, nivolumab was restarted again. At 18 months after surgery, there were no recurrent NSCLC lesions. Immunohistochemical analysis of peritumoral T lymphocytes showed higher expression of T cell immunoglobulin and mucin domain-containing protein 3 (TIM-3) and lymphocyte activation gene 3 (LAG-3) in recurrent lesions of bone and small intestine than in primary lesions. Upregulation of TIM-3 and LAG-3 could be associated with mechanisms of adaptive resistance to nivolumab in this case. Here, we report a successful case of continued nivolumab therapy with remission after local treatments consisting of radiation therapy and surgical resection for oligometastases. Continuation of immune checkpoint inhibitor (ICI) treatment may be worth considering if oligometastases can be controlled. KEY POINTS: Significant findings of the study We report a successful case of continued nivolumab treatment with remission after local treatment (radiation therapy and surgical resection) for oligometastases. What this study adds Upregulation of T cell immunoglobulin and mucin domain-containing protein 3 and lymphocyte-activation gene 3 could be associated with mechanisms of adaptive resistance to nivolumab.

Phase II trial of induction chemotherapy of pemetrexed plus split-dose cisplatin followed by pemetrexed maintenance for untreated non-squamous non-small-cell lung cancer.

PURPOSE: We conducted a phase II trial to evaluate the efficacy and safety of induction chemotherapy of pemetrexed plus split-dose cisplatin followed by pemetrexed maintenance for advanced non-squamous non-small-cell lung cancer (NSCLC). METHODS: Patients with advanced or recurrent untreated non-squamous NSCLC received split-dose cisplatin (40 mg/m2, days 1 and 8) plus pemetrexed (500 mg/m2, day 1) tri-weekly. After four cycles of induction, patients without disease progression received pemetrexed maintenance until disease progression or unacceptable toxicity. The primary endpoint was the 1-year survival rate. The secondary endpoints were progression-free survival (PFS), overall survival (OS), response in induction phase, and safety. RESULTS: From February 2012 to September 2014, 53 assessable patients were enrolled in this study. Thirty-eight (71.7%) patients completed induction therapy, while 35 (66.0%) received maintenance therapy. The 1-year survival rate was 67.7%. The median PFS and OS were 5.3 and 18.6 months, respectively. The response rate and disease control rate (DCR) during the induction phase were 37.7 and 86.8%, respectively. Eight patients (15.1%) discontinued the therapy due to adverse events (AEs) during the induction phase, but both hematological and non-hematological AEs were infrequent. CONCLUSIONS: Treatment with induction chemotherapy of pemetrexed plus split-dose cisplatin showed a promising 1-year survival rate, DCR, and transition rate into maintenance phase. This regimen is feasible and well-tolerated. A phase III study comparing this regimen with conventional tri-weekly regimen is warranted.

Overcoming chemoresistance of small-cell lung cancer through stepwise HER2-targeted antibody-dependent cell-mediated cytotoxicity and VEGF-targeted antiangiogenesis.

Small-cell lung cancer (SCLC) easily recurs with a multidrug resistant phenotype. However, standard therapeutic strategies for relapsed SCLC remain unestablished. We found that human epidermal growth factor receptor 2 (HER2) is not only expressed in pretreated human SCLC specimens, but is also upregulated when HER2-positive SCLC cells acquire chemoresistance. Trastuzumab induced differential levels of antibody-dependent cell-mediated cytotoxicity (ADCC) to HER2-positive SCLC cells. Furthermore, as a mechanism of the differential levels of ADCC, we have revealed that coexpression of intracellular adhesion molecule (ICAM)-1 on SCLC cells is essential to facilitate and accelerate the trastuzumab-mediated ADCC. Although SN-38-resistant SCLC cells lacking ICAM-1 expression were still refractory to trastuzumab, their in vivo growth was significantly suppressed by bevacizumab treatment due to dependence on their distinctive and abundant production of vascular endothelial growth factor. Collectively, stepwise treatment with trastuzumab and bevacizumab is promising for the treatment of chemoresistant SCLC.

Statins decrease lung inflammation in mice by upregulating tetraspanin CD9 in macrophages.

Tetraspanins organize protein complexes in tetraspanin-enriched membrane microdomains that are distinct from lipid rafts. Our previous studies suggested that reduction in the levels of tetraspanins CD9 and CD81 may be involved in the progression of inflammatory lung diseases, especially COPD. To search for agents that increase the levels of these tetraspanins, we screened 1,165 drugs in clinical use and found that statins upregulate CD9 and CD81 in RAW264.7 macrophages. The lipophilic statins, fluvastatin and simvastatin, reversed LPS-induced downregulation of CD9 and CD81, simultaneously preventing TNF-α and matrix metalloproteinase-9 production and spreading of RAW264.7 cells. These statins exerted anti-inflammatory effects in vitro in wild-type macrophages but not in CD9 knockout macrophages, and decreased lung inflammation in vivo in wild-type mice but not in CD9 knockout mice, suggesting that their effects are dependent on CD9. Mechanistically, the statins promoted reverse transfer of the LPS-signaling mediator CD14 from lipid rafts into CD9-enriched microdomains, thereby preventing LPS receptor formation. Finally, upregulation of CD9/CD81 by statins was related to blockade of GTPase geranylgeranylation in the mevalonate pathway. Our data underscore the importance of the negative regulator CD9 in lung inflammation, and suggest that statins exert anti-inflammatory effects by upregulating tetraspanin CD9 in macrophages.

Calretinin mediates apoptosis in small cell lung cancer cells expressing tetraspanin CD9.

A majority of small cell lung cancer (SCLC) cells lack a metastasis suppressor, tetraspanin CD9, and CD9 expression promotes their apoptosis. By a proteomics-based approach, we compared an SCLC cell line with its CD9 transfectant and found that a calcium-binding neuronal protein, calretinin, is upregulated in CD9-positive SCLC cells. Ectopic or anticancer drug-induced CD9 expression upregulated calretinin, whereas CD9 knockdown down-regulated calretinin in SCLC cells. When calretinin was knocked down, CD9-positive SCLC cells revealed increased Akt phosphorylation and decreased apoptosis. These results suggest that CD9 positively regulates the expression of calretinin that mediates proapoptotic effect in SCLC cells.

Validation of noninvasive morphological and diffusion imaging in mouse emphysema by micro-computed tomography and hyperpolarized (129)Xe magnetic resonance imaging.

Animal disease models are pivotal in investigating the pathogenesis of emphysema and developing novel drugs, but the modalities to evaluate murine emphysema models have been of limited validity and sensitivity. In this study, we evaluated hyperpolarized (129)Xe magnetic resonance imaging (MRI) and micro-computed tomography (micro-CT) compared with traditional methods, such as plethysmography and histology. Elastase-treated mice and adiponectin knockout mice were used as murine emphysema models to evaluate these modalities. Three weeks after elastase administration, significant and heterogeneous emphysema was evaluated according to the mean linear intercept and plethysmography parameters. Notably, the distribution of low-density areas, as examined by micro-CT, correlated with the mean linear intercept and plethysmography parameters in whole lungs. These correlations were also observed in regional areas. Furthermore, we introduced hyperpolarized (129)Xe MRI, which can evaluate gas exchange between the alveoli and blood during spontaneous breathing. Parameters of gas exchange (fD) and alveolar size (Vs/Va) were significantly decreased in elastase-treated mice, and moderately correlated with the plethysmography parameters. Of importance, we could detect a decrease of the fD value in low-density areas with micro-CT, suggesting that gas exchange decreased in emphysematous lesions. Likewise, these parameters (fD and Vs/Va) were also decreased in adiponectin knockout mice, which exhibit emphysema with a homogeneous distribution. We demonstrated the feasibility of (129)Xe MRI and micro-CT in combination with traditional modalities. These noninvasive modalities provide complementary data that can be used for repeated estimations of regional gas exchange and lung morphology.

Deletion of tetraspanin CD9 diminishes lymphangiogenesis in vivo and in vitro.

Tetraspanins have emerged as key players in malignancy and inflammatory diseases, yet little is known about their roles in angiogenesis, and nothing is known about their involvement in lymphangiogenesis. We found here that tetraspanins are abundantly expressed in human lymphatic endothelial cells (LEC). After intrathoracic tumor implantation, metastasis to lymph nodes was diminished and accompanied by decreased angiogenesis and lymphangiogenesis in tetraspanin CD9-KO mice. Moreover, lymphangiomas induced in CD9-KO mice were less pronounced with decreased lymphangiogenesis compared with those in wild-type mice. Although mouse LEC isolated from CD9-KO mice showed normal adhesion, lymphangiogenesis was markedly impaired in several assays (migration, proliferation, and cable formation) in vitro and in the lymphatic ring assay ex vivo. Consistent with these findings in mouse LEC, knocking down CD9 in human LEC also produced decreased migration, proliferation, and cable formation. Immunoprecipitation analysis demonstrated that deletion of CD9 in LEC diminished formation of functional complexes between VEGF receptor-3 and integrins (α5 and α9). Therefore, knocking down CD9 in LEC attenuated VEGF receptor-3 signaling, as well as downstream signaling such as Erk and p38 upon VEGF-C stimulation. Finally, double deletion of CD9/CD81 in mice caused abnormal development of lymphatic vasculature in the trachea and diaphragm, suggesting that CD9 and a closely related tetraspanin CD81 coordinately play an essential role in physiological lymphangiogenesis. In conclusion, tetraspanin CD9 modulates molecular organization of integrins in LEC, thereby supporting several functions required for lymphangiogenesis.

Suppression of metastases of small cell lung cancer cells in mice by a peptidic CXCR4 inhibitor TF14016.

CXCL12 is a chemokine essential for the organ-specific spread of a variety of cancers including small cell lung cancer (SCLC). Here, we examined the anti-metastatic efficacy of TF14016, a small peptidic inhibitor of CXCL12 receptor CXCR4, in SCLC. Treatment of mice with TF14016 significantly suppressed pulmonary metastases of CXCR4-expressing SCLC in size and number. Furthermore, histological examination revealed that the expression of vascular endothelial cell growth factor and the density of CD31-positive microvessels in metastatic foci were both significantly reduced in TF14016-treated mice. Collectively, CXCR4 could be an attractive target for anti-metastatic and anti-angiogenic therapy in SCLC.

Inhibitory roles of signal transducer and activator of transcription 3 in antitumor immunity during carcinogen-induced lung tumorigenesis.

Stat3 mediates a complex spectrum of cellular responses, including inflammation, cell proliferation, and apoptosis. Although evidence exists in support of a positive role for Stat3 in cancer, its role has remained somewhat controversial because of insufficient study of how its genetic deletion may affect carcinogenesis in various tissues. In this study, we show using epithelium-specific knockout mice (Stat3(Δ/Δ)) that Stat3 blunts rather than supports antitumor immunity in carcinogen-induced lung tumorigenesis. Although Stat3(Δ/Δ) mice did not show any lung defects in terms of proliferation, apoptosis, or angiogenesis, they exhibited reduced urethane-induced tumorigenesis and increased antitumor inflammation and natural killer (NK) cell immunity. Comparative microarray analysis revealed an increase in Stat3(Δ/Δ) tumors in proinflammatory chemokine production and a decrease in MHC class I antigen expression associated with NK cell recognition. Consistent with these findings, human non-small cell lung cancer (NSCLC) cells in which Stat3 was silenced displayed an enhancement of proinflammatory chemokine production, reduced expression of MHC class I antigen, and increased susceptibility to NK cell-mediated cytotoxicity. In addition, supernatants from Stat3-silenced NSCLC cells promoted monocyte migration. Collectively, our findings argue that Stat3 exerts an inhibitory effect on antitumor NK cell immunity in the setting of carcinogen-induced tumorigenesis.

HER2 as therapeutic target for overcoming ATP-binding cassette transporter-mediated chemoresistance in small cell lung cancer.

Small cell lung cancer (SCLC) easily acquires multidrug resistance after successful initial therapy. Overexpression of ATP-binding cassette (ABC) transporters is important for the multidrug resistance. Among them, ABCB1 and ABCG2 are known to be upregulated in chemoresistant SCLC cells. We found that human epidermal growth factor receptor 2 (HER2) expressions are also upregulated in chemoresistant SBC-3/ETP, SBC-3/SN-38, and SBC-3/CDDP cells, compared with chemosensitive SBC-3 cells. Lapatinib, a tyrosine kinase inhibitor of HER2, could not suppress proliferation of these HER2-positive SCLC cells alone but successfully restored chemosensitivity to etoposide and SN-38 with a clinically applicable concentration. The reversal effect of lapatinib was thought to be caused by inhibition of drug efflux pump functions of ABC transporters, although lapatinib itself has been reported to be a substrate for them. Moreover, knocking down of HER2 by an short interfering RNA weakened the effect of lapatinib on ABCB1, indicating the involvement of HER2 in the inhibitory mechanisms. Notably, we showed that caveolin-1 and Src play key roles in modulating ABCB1 function via HER2 inactivation. In SBC-3/ETP cells, dephosphorylation of HER2 by lapatinib activates Src and successively leads to increased caveolin-1 phosphorylation. Through this process, caveolin-1 dissociates from HER2 and strengthens association with ABCB1, and finally impairs the pump functions. Furthermore, we showed that treatment by lapatinib in combination with etoposide or irinotecan significantly suppresses the growth of subcutaneous SBC-3/ETP and SBC-3/SN-38 tumors in mice, respectively. Collectively, these results indicate that combination therapy with lapatinib and cytotoxic agents could conquer ABC transporter-mediated chemoresistance especially in HER2-positive SCLC.

CXCL12 as a biological marker for the diagnosis of tuberculous pleurisy.

Although a chemokine CXCL12 is implicated in some infectious diseases, especially those in which T cell-mediated immunity plays critical roles, the relevance of CXCL12 to tuberculosis has never been elucidated. To determine the clinical efficacy of CXCL12 as a diagnostic marker for tuberculous (TB) pleurisy, we measured CXCL12 concentration in pleural fluid and serum from patients with various etiologies. Of 60 patients with pleural fluid, the median age of TB patients was 52 which was significantly lower than 71 of non-TB patients (P < 0.01). CXCL12 level in TB effusion (4456 ± 1013 pg/mL, n = 15) was significantly higher than non-TB effusion (2851 ± 1229 pg/mL, n = 45) (P < 0.01). On the other hand, serum CXCL12 level showed no significant differences among TB pleurisy, non-TB pleurisy, and normal healthy subjects. The sensitivity and specificity of CXCL12 in pleural fluid for the diagnosis of TB pleurisy was 60.0% and 93.2% (cut-off value = 4600 pg/mL), respectively. Area under the receiver operating characteristic (ROC) curve (AUC) for CXCL12 was 0.84. As the source of CXCL12, pleural mesothelium, endothelium of pulmonary vessels, bronchial epithelium, multinucleated giant epithelioid cells, and macrophages were positive for CXCL12 staining. Increased CXCL12 level in pleural fluid could be an informative diagnostic marker for differentiating TB pleurisy from other etiologies.

Cell surface tetraspanin CD9 mediates chemoresistance in small cell lung cancer.

Small cell lung cancer (SCLC) is an aggressive malignancy with extremely high mortality due to the appearance of widespread metastases early in its clinical course and rapid acquisition of chemoresistance after initial therapy. A theory of cell adhesion-mediated drug resistance is thought to be a principal mechanism in which extracellular matrix proteins provide a survival advantage against cytotoxic drug-induced apoptosis. We found that the tetraspanin family member CD9 was expressed preferentially in SCLC tumors and metastases from three of seven relapsed patients, whereas chemonaïve primary tumors from 16 patients were CD9 negative with only one exception. Additionally, CD9 was highly expressed on SCLC cell lines rendered resistant to cisplatin or etoposide, and was upregulated in parental chemosensitive cells within 48 hours after exposure to either of these compounds. CD9-expressing chemoresistant SCLC cells adhered more tightly to fibronectin via ß1 integrin, but they were less motile than the respective chemosensitive parental lines. Notably, treatment of the chemoresistant cells with chemokine CXCL12 downregulated CD9 and transiently restored motility. Moreover, selective targeting of CD9 by treatment with specific monoclonal antibody ALB6 or a small interfering RNA triggered apoptosis in the chemoresistant cells. Taken together, our findings implicate CD9 in the cell adhesion-mediated drug resistance mechanism, highlighting CD9 as an attractive therapeutic target to improve therapeutic outcomes in SCLC.