Deep Learning for the Classification of Small (≤2 cm) Pulmonary Nodules on CT Imaging: A Preliminary Study.

RATIONALE AND OBJECTIVES: We aimed to present a deep learning-based malignancy prediction model (CT-lungNET) that is simpler and faster to use in the diagnosis of small (≤2 cm) pulmonary nodules on nonenhanced chest CT and to preliminarily evaluate its performance and usefulness for human reviewers. MATERIALS AND METHODS: A total of 173 whole nonenhanced chest CT images containing 208 pulmonary nodules (94 malignant and 11 benign nodules) ranging in size from 5 mm to 20 mm were collected. Pathologically confirmed nodules or nodules that remained unchanged for more than 1 year were included, and 30 benign and 30 malignant nodules were randomly assigned into the test set. We designed CT-lungNET to include three convolutional layers followed by two fully-connected layers and compared its diagnostic performance and processing time with those of AlexNET by using the area under the receiver operating curve (AUROC). An observer performance test was conducted involving eight human reviewers of four different groups (medical students, physicians, radiologic residents, and thoracic radiologists) at test 1 and test 2, referring to the CT-lungNET's malignancy prediction rate with pairwise comparison receiver operating curve analysis. RESULTS: CT-lungNET showed an improved AUROC (0.85; 95% confidence interval: 0.74-0.93), compared to that of the AlexNET (0.82; 95% confidence interval: 0.71-0.91). The processing speed per one image slice for CT-lungNET was about 10 times faster than that for AlexNET (0.90 vs. 8.79 seconds). During the observer performance test, the classification performance of nonradiologists was increased with the aid of CTlungNET, (mean AUC improvement: 0.13; range: 0.03-0.19) but not significantly so in the radiologists group (mean AUC improvement: 0.02; range: -0.02 to 0.07). CONCLUSION: CT-lungNET was able to provide better classification results with a significantly shorter amount of processing time as compared to AlexNET in the diagnosis of small pulmonary nodules on nonenhanced chest CT. In this preliminary observer performance test, CT-lungNET may have a role acting as a second reviewer for less experienced reviewers, resulting in enhanced performance in the diagnosis of early lung cancer.

Gambogic Acid and Its Analogs Inhibit Gap Junctional Intercellular Communication.

Gap junctions (GJs) are intercellular channels composed of connexins. Cellular molecules smaller than 1 kDa can diffuse through GJs by a process termed gap junctional intercellular communication (GJIC), which plays essential roles in various pathological and physiological conditions. Gambogic acid (GA), a major component of a natural yellow dye, has been used as traditional medicine and has been reported to have various therapeutic effects, including an anti-cancer effect. In this study, two different GJ assay methods showed that GA and its analogs inhibited GJIC. The inhibition was rapidly reversible and was not mediated by changes in surface expression or S368 phosphorylation of Cx43, cellular calcium concentration, or redox state. We also developed an assay system to measure the intercellular communication induced by Cx40, Cx30, and Cx43. Dihydrogambogic acid (D-GA) potently inhibited GJIC by Cx40 (IC50 = 5.1 µM), whereas the IC50 value of carbenoxolone, which is known as a broad spectrum GJIC inhibitor, was 105.2 µM. Thus, D-GA can act as a pharmacological tool for the inhibition of Cx40.

Crucial role of HMGA1 in the self-renewal and drug resistance of ovarian cancer stem cells.

Cancer stem cells are a subpopulation of cancer cells characterized by self-renewal ability, tumorigenesis and drug resistance. The aim of this study was to investigate the role of HMGA1, a chromatin remodeling factor abundantly expressed in many different cancers, in the regulation of cancer stem cells in ovarian cancer. Spheroid-forming cancer stem cells were isolated from A2780, SKOV3 and PA1 ovarian cancer cells by three-dimensional spheroid culture. Elevated expression of HMGA1 was observed in spheroid cells along with increased expression of stemness-related genes, such as SOX2, KLF4, ALDH, ABCB1 and ABCG2. Furthermore, spheroid A2780 cells, compared with adherent cells, showed higher resistance to chemotherapeutic agents such as paclitaxel and doxorubicin. HMGA1 knockdown in spheroid cells reduced the proliferative advantage and spheroid-forming efficiency of the cells and the expression of stemness-related genes. HMGA1 overexpression in adherent A2780 cells increased cancer stem cell properties, including proliferation, spheroid-forming efficiency and the expression of stemness-related genes. In addition, HMGA1 regulated ABCG2 promoter activity through HMGA1-binding sites. Knockdown of HMGA1 in spheroid cells reduced resistance to chemotherapeutic agents, whereas the overexpression of HMGA1 in adherent ovarian cancer cells increased resistance to chemotherapeutic agents in vitro. Furthermore, HMGA1-overexpressing A2780 cells showed a significant survival advantage after chemotherapeutic agent treatment in a xenograft tumorigenicity assay. Together, our results provide novel insights regarding the critical role of HMGA1 in the regulation of the cancer stem cell characteristics of ovarian cancer cells, thus suggesting that HMGA1 may be an important target in the development of therapeutics for ovarian cancer patients.

Subcutaneous veltuzumab, a humanized anti-CD20 antibody, in the treatment of refractory pemphigus vulgaris.

IMPORTANCE B-cell depletion with the anti-CD20 antibody rituximab is highly effective for pemphigus vulgaris (PV) treatment. However,most patients experience relapse, and intravenous rituximab infusions are expensive. Therefore, cost-effective anti-CD20 therapies are desirable.OBSERVATIONS A compassionate-use investigational new drug protocol was approved to administer veltuzumab, a second-generation humanized anti-CD20 antibody, to a patient with refractory PV. Veltuzumab was administered as two 320-mg (188mg/m2) subcutaneous doses 2 weeks apart, resulting in complete remission of disease off therapy. The disease relapsed 2 years after treatment. A second cycle of subcutaneous veltuzumab, using the same dosage regimen, again induced complete remission off therapy, which remained at9 months. No serious adverse events occurred during 35 months of follow-up. Serum veltuzumab levels were 22 and 29 µg/mL 2 weeks after the first dose of each cycle, and the drug remained detectable in the serum for longer than 3 months. Relapse and response to veltuzumab generally correlated with desmoglein 3 enzyme-linked immunosorbent assay index values. Shortly after a relapse that occurred after a long-term remission, the patient demonstrated an elevated naive (CD19+CD27−) to memory (CD19+CD27+) B-cell ratio of 19.5 and transitional (CD19+CD24+CD38+) B-cell frequency of 12.5%.CONCLUSIONS AND RELEVANCE Subcutaneous veltuzumab may be a safe, effective, and more economical alternative to intravenous rituximab for PV therapy. Clinical trials of subcutaneous veltuzumab for PV are warranted.

Evaluation of anticancer activity of dehydrocostuslactone in vitro.

Dehydrocostuslactone is a sesquiterpene lactone derived from Saussurea lappa, a plant used in traditional herbal medicines. The anti-proliferative activity of dehydrocostuslactone was investigated in human breast cancer (MDA-MB-231, MDA-MB-453 and SK-BR-3) and ovarian cancer (SK-OV-3 and OVCAR3) cell lines using the methyl thiazolyl tetrazolium assay. In the cells, exposure to dehydrocostuslactone resulted in a dose-dependent decline in cell proliferation. The IC50 value was found to be 21.5, 43.2, 25.6, 15.9 and 10.8 µM in MDA-MB-231, MDA-MB-453, SK-BR-3, SK-OV-3 and OVCAR3 cells, respectively. Dehydrocostuslactone exerted its antiproliferative effects by inducing cell cycle arrest and apoptosis. Cell cycle distribution and apoptosis were analyzed using flow cytometry in cell lines exposed to 10 µM dehydrocostuslactone for 48 h. Compared to the controls, exposure to dehydrocostuslactone resulted in accumulation in the G2/M phase and a marked increase in the apoptotic cell population. These results suggest that dehydrocostuslactone has potential anticancer properties.

5-Fluorouracil combined with apigenin enhances anticancer activity through induction of apoptosis in human breast cancer MDA-MB-453 cells.

We investigated the effects of combined treatment with 5-fluorouracil and apigenin on proliferation and apoptosis, as well as the underlying mechanism, in human breast cancer MDA-MB-453 cells. The MDA-MB-453 cells, which have been shown to overexpress ErbB2, were resistant to 5-fluorouracil; 5-fluorouracil exhibited a small dose-dependent anti-proliferative effect, with an IC50 of 90 microM. Interestingly, combined treatment with apigenin significantly decreased the resistance. Cellular proliferation was significantly inhibited in cells exposed to 5-fluorouracil at its IC50 and apigenin (5, 10, 50 and 100 microM), compared with proliferation in cells exposed to 5-fluorouracil alone. This inhibition in turn led to apoptosis, as evidenced by an increased number of apoptotic cells and the activation of caspase-3. To investigate the mechanism by which the combination of 5-fluorouracil and apigenin induces apoptosis, ErbB2 expression was analyzed. The level of ErbB2 was unchanged by 5-fluorouracil alone but was drastically reduced in cells treated with 5-fluorouracil plus apigenin. Moreover, compared with 5-fluorouracil alone, 5-fluorouracil in combination with apigenin at concentrations >10 microM exerted a pro-apoptotic effect via the inhibition of Akt expression. Taken together, our results suggest that 5-fluorouracil acts synergistically with apigenin inhibiting cell growth and inducing apoptosis via the down-regulation of ErbB2 expression and Akt signaling.

Large cerebral artery involvement in CADASIL.

The authors evaluated the involvement of large cerebral artery in 13 patients with cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) with angiography (12 MR and one conventional). Five patients (38%) showed stenosis: at the middle cerebral artery in three, vertebral artery in one, and the internal carotid artery in one. The stenosis persisted on follow-up angiogram in two patients. There were no differences in risk factors between patients with angiographic abnormality and those without, suggesting occasional involvement of large vessels in CADASIL.