Identification of a Gene Expression Signature to Predict the Risk of Early Recurrence and the Degree of Immune Cell Infiltration in Triple-negative Breast Cancer

BACKGROUND/AIM

Patients with triple-negative breast cancer (TNBC) have a high rate of recurrence within 3 years of diagnosis and a high rate of death within 5 years compared to other subtypes. The number of clinical trials investigating various new agents and combination therapies has recently increased; however, current strategies benefit only a minority of patients. This study aimed to identify specific genes that predict patients at high risk of recurrence and the immune status of the tumor microenvironment at an early stage, thereby providing insight into potential therapeutic targets to improve clinical outcomes in TNBC patients.

MATERIALS AND METHODS

We evaluated the prognostic significance of microarray mRNA expression of 20,603 genes in 233 TNBC patients from the METABRIC dataset and further validated the results using RNA-seq mRNA expression data in 143 TNBC patients from the GSE96058 dataset.

RESULTS

Eighteen differentially expressed genes (AKNA, ARHGAP30, CA9, CD3D, CD3G, CD6, CXCR6, CYSLTR1, DOCK10, ENO1, FLT3LG, IFNG, IL2RB, LPXN, PRKCB, PVRIG, RASSF5, and STAT4) identified in both datasets were found to be reliable biomarkers for predicting TNBC recurrence and progression. Notably, the genes whose low expression was associated with increased risk of recurrence and death were immune-related genes, with significant differences in levels of immune cell infiltration in the tumor microenvironment between high- and low- expression groups.

CONCLUSION

Genes reported herein may be effective biomarkers to identify TNBC patients who will and will not benefit from immunotherapy and may be particularly important genes for developing future treatment strategies, including immunotherapy.

Luminal B Breast Cancer Coexpressing p62 and ALDH1A3 Is Less Susceptible to Radiotherapy

BACKGROUND/AIM

We have reported that p62 (also known as sequestosome 1) is needed for survival/proliferation and tumor formation by aldehyde dehydrogenase 1 (ALDH1) -positive cancer stem cells (CSCs) and that p62high ALDH1A3high expression is associated with a poor prognosis in luminal B breast cancer. However, the association between p62high ALDH1A3high and the benefit from radiotherapy in patients with luminal B breast cancer remains unclear.

MATERIALS AND METHODS

Datasets from the Molecular Taxonomy of Breast Cancer International Consortium (METABRIC) and The Cancer Genome Atlas (TCGA) were downloaded, and data from p62high ALDH1A3high luminal B patients treated without or with radiotherapy were analyzed by Kaplan-Meier and multivariate Cox regression analyses. We also performed an in vitro tumor sphere formation assay after X-ray irradiation using p62-knockdown ALDH1high luminal B BT-474 cells.

RESULTS

p62high ALDH1A3high patients had poorer clinical outcomes than other luminal B breast cancer patients treated with radiotherapy. The combination of p62 DsiRNA KD and X-ray irradiation suppressed in vitro tumor sphere formation by ALDH1high BT-474 cells. These results suggest that p62 is involved in the reduced effect of X-ray irradiation on ALDH1-positive luminal B breast CSCs.

CONCLUSION

p62 and ALDH1A3 may serve as prognostic biomarkers for luminal B breast cancer patients treated with radiotherapy. Additionally, the combination of p62 inhibition and radiotherapy could be useful for targeted strategies against ALDH1-positive luminal B breast CSCs.

High expression of PKCλ and ALDH1A3 indicates a poor prognosis, and PKCλ is required for the asymmetric cell division of ALDH1A3-positive cancer stem cells in PDAC

Pancreatic ductal adenocarcinoma (PDAC) is the cancer with the poorest prognosis. One of the major properties reflecting its poor prognosis is high-grade heterogeneity, which leads to insensitivity to anticancer treatments. Cancer stem cells (CSCs) acquire phenotypic heterogeneity, generating abnormally differentiated cells by asymmetric cell division. However, the detailed mechanism leading to phenotypic heterogeneity is largely unknown. Here, we showed that PDAC patients with co-upregulation of PKCλ and ALDH1A3 had the poorest clinical outcome. PKCλ knockdown by DsiRNA in the ALDH1high population of PDAC MIA-PaCa-2 cells attenuated the asymmetric distribution of the ALDH1A3 protein. To monitor asymmetric cell division of ALDH1A3-positive PDAC CSCs, we established stable Panc-1 PDAC clones expressing ALDH1A3-turboGFP (Panc-1-ALDH1A3-turboGFP cells). In addition to MIA-PaCa-2-ALDH1high cells, turboGFPhigh cells sorted from Panc-1-ALDH1A3-turboGFP cells showed asymmetric cell propagation of ALDH1A3 protein. PKCλ DsiRNA in Panc-1-ALDH1A3-turboGFP cells also attenuated the asymmetric distribution of ALDH1A3 protein. These results suggest that PKCλ regulates the asymmetric cell division of ALDH1A3-positive PDAC CSCs. Furthermore, Panc-1-ALDH1A3-turboGFP cells can be useful for the visualization and monitoring of CSC properties such as asymmetric cell division of ALDH1A3-positive PDAC CSCs in time-lapse imaging.

High SLC20A1 Expression Indicates Poor Prognosis in Prostate Cancer

BACKGROUND/AIM

High expression of solute carrier family 20 member 1 (SLC20A1) indicates poor clinical outcomes for patients with breast cancer subtypes treated with endocrine therapy and radiotherapy. However, the association between SLC20A1 expression and clinical outcomes in prostate cancer remains to be determined.

MATERIALS AND METHODS

Open-source datasets (The Cancer Genome Atlas prostate, Stand Up to Cancer-Prostate Cancer Foundation Dream Team, and The Cancer Genome Atlas PanCancer Atlas) were downloaded and analyzed. SLC20A1 expression was analyzed in prostate cancer and normal prostate tissue. Survival analysis using Kaplan-Meier curves and Cox regression analysis were performed to examine patient prognosis, as well as the effects of endocrine therapy and radiotherapy on high SLC20A1 expression in patients with prostate cancer.

RESULTS

SLC20A1 was higher in prostate cancer than in normal prostate tissues. High SLC20A1 expression predicted poor disease-free and progression-free survival. Following endocrine therapy, no significant difference in prognosis was observed between patients with high SLC20A1 and those with low SLC20A1 expression. However, following radiotherapy, high SLC20A1 expression tended to be associated with a poor clinical outcome.

CONCLUSION

SLC20A1 may serve as a prognostic biomarker for prostate cancer, and the recommended treatment for patients with high SLC20A1 expression is endocrine therapy.

High SLC20A1 Expression Is Associated With Poor Prognosis for Radiotherapy of Estrogen Receptor-positive Breast Cancer

BACKGROUND/AIM

Radiotherapy is one of the main treatments for estrogen receptor-positive (ER+) breast cancer. However, in some ER+ breast cancer cases, radiotherapy is insufficient to inhibit progression and there is a lack of markers to predict radiotherapy insensitivity. Solute carrier family 20 member 1 (SLC20A1) is a sodium/inorganic phosphate symporter, which has been proposed to be a viable prognostic marker for luminal A and B types of ER+ breast cancer. The present study examined the possibility of SLC20A1 as a novel biomarker for the prediction of radiotherapy efficiency.

PATIENTS AND METHODS

The Molecular Taxonomy of Breast Cancer International Consortium dataset was downloaded from cBioportal and the prognosis of patients with high SLC20A1 expression (SLC20A1 ^high ) was compared with that of patients with low SLC20A1 expression, without or with radiotherapy and tumor stages I, II, and III, using the Kaplan-Meier method and multivariate Cox regression analyses of disease-specific and relapse-free survival.

RESULTS

Patients in the SLC20A1 ^high group with radiotherapy showed poor clinical outcomes in both luminal A and luminal B breast cancers. Furthermore, in luminal A breast cancer at tumor stage I, patients in the SLC20A1 ^high  group with radiotherapy also showed poor clinical outcomes. Therefore, these results suggest that radiotherapy is insufficient for patients in the SLC20A1 ^high group for both luminal A and B types, and especially for the luminal A type at tumor stage I.

CONCLUSION

SLC20A1 can be used as a prognostic marker for the prediction of the efficacy of radiotherapy for luminal A and luminal B breast cancers.

High Expression of p62 and ALDH1A3 Is Associated With Poor Prognosis in Luminal B Breast Cancer

BACKGROUND/AIM

p62 (also known as sequestosome 1) is involved in cancer progression, and high expression of p62 indicates poor clinical outcome in several cancer types. However, the association between p62 gene expression and cancer stem cells (CSCs) in breast cancer subtypes remains unclear.

MATERIALS AND METHODS

In the present study, genomic datasets of primary breast cancer (The Cancer Genome Atlas, n=593; and Molecular Taxonomy of Breast Cancer International Consortium, n=2,509) were downloaded. p62 Expression was then examined in normal and breast cancer tissues derived from the same patients. Kaplan-Meier and multivariate Cox regression analyses were employed to evaluate disease-specific survival. Next, the effect on cell viability and in vitro tumor-sphere formation of p62 knockdown using targeted small interfering RNA was assessed by using cells with high activity of aldehyde dehydrogenase 1 (ALDH1^high).

RESULTS

Patients with normal-like, luminal A or luminal B breast cancer with p62^high had poor prognosis. Furthermore, patients with p62^high ALDH1A3^high luminal B type also exhibited poor prognoses. Knockdown of p62 suppressed viability and tumor-sphere formation by ALDH1^high cells of the luminal B-type cell lines BT-474 and MDA-MB-361. These results suggest that p62 is essential for cancerous progression of ALDH1-positive luminal B breast CSCs, and contributes to poor prognosis of luminal B breast cancer.

CONCLUSION

p62 is potentially a prognostic marker and therapeutic target for ALDH1-positive luminal B breast CSCs.

High expression of SLC20A1 is less effective for endocrine therapy and predicts late recurrence in ER-positive breast cancer

Estrogen receptor-positive (ER+) breast cancer intrinsically confers satisfactory clinical outcomes in response to endocrine therapy. However, a significant proportion of patients with ER+ breast cancer do not respond well to this treatment. Therefore, to evaluate the effects of endocrine therapy, there is a need for identification of novel markers that can be used at the time of diagnosis for predicting clinical outcomes, especially for early-stage and late recurrence. Solute carrier family 20 member 1 (SLC20A1) is a sodium/inorganic phosphate symporter that has been proposed to be a viable prognostic marker for the luminal A and luminal B types of ER+ breast cancer. In the present study, we examined the possible association of SLC20A1 expression with tumor staging, endocrine therapy and chemotherapy in the luminal A and luminal B subtypes of breast cancer. In addition, we analyzed the relationship between SLC20A1 expression and late recurrence in patients with luminal A and luminal B breast cancer following endocrine therapy. We showed that patients with higher levels of SLC20A1 expression (SLC20A1^high) exhibited poorer clinical outcomes in those with tumor stage I luminal A breast cancer. In addition, this SLC20A1^high subgroup of patients exhibited less responses to endocrine therapy, specifically in those with the luminal A and luminal B subtypes of breast cancer. However, patients with SLC20A1^high showed good clinical outcomes following chemotherapy. Patients tested to be in the SLC20A1^high group at the time of diagnosis also showed a higher incidence of recurrence compared with those with lower expression levels of SLC20A1, at >15 years for luminal A breast cancer and at 10–15 years for luminal B breast cancer. Therefore, we conclude that SLC20A1^high can be used as a prognostic biomarker for predicting the efficacy of endocrine therapy and late recurrence for ER+ breast cancer.

GLO 1 and PKCλ Regulate ALDH1-positive Breast Cancer Stem Cell Survival

BACKGROUND/AIM

We examined the inhibitory effects of both glyoxalase 1 (GLO 1) and protein kinase C (PKC)λ in aldehyde dehydrogenase 1 (ALDH1)-positive breast cancer stem cells (CSCs).

MATERIALS AND METHODS

Breast cancer genomics datasets (TCGA, n=593; METABRIC, n=1904) were downloaded and statistically analyzed. The effects of GLO 1 and PKCλ on trypan blue staining and tumor-sphere formation by ALDH1^high cells derived from triple negative breast cancer (TNBC) and basal-like breast cancer were examined.

RESULTS

GLO 1^high, PKCλ^high, and ALDH1A3^high tumors were enriched in stage I/II/III/IV samples, associated with the HER2 and TNBC subtypes according to receptor status, and associated with the HER2-enriched and basal-like subtypes according to PAM50. Inhibition of either GLO 1 (TLSC702) or PKCλ (ANF) suppressed tumor-sphere formation and enhanced death in ALDH1^high cells. TLSC702 also effectively inhibited tumor-sphere formation and induced death in PKCλ knockout ALDH1^high cells.

CONCLUSION

GLO 1 and PKCλ are important for the survival of ALDH1-positive breast CSCs, and may represent potential therapeutic targets for the treatment of ALDH1-positive breast CSCs.

Glyoxalase 1 and protein kinase Cλ as potential therapeutic targets for late-stage breast cancer

Cancer cells upregulate the expression levels of glycolytic enzymes in order to reach the increased glycolysis required. One such upregulated glycolytic enzyme is glyoxalase 1 (GLO 1), which catalyzes the conversion of toxic methylglyoxal to nontoxic S-D-lactoylglutathione. Protein kinase Cλ (PKCλ) is also upregulated in various types of cancer and is involved in cancer progression. In the present study, the association between enhanced glycolysis and PKCλ in breast cancer was investigated. In human breast cancer, high GLO 1 expression was associated with high PKCλ expression at the protein (P<0.01) and mRNA levels (P<0.01). Furthermore, Wilcoxon and Cox regression model analysis revealed that patients with stage III–IV tumors with high GLO 1 and PKCλ expression had poor overall survival compared with patients expressing lower levels of these genes [P=0.040 (Gehan-Breslow generalized Wilcoxon test) and P=0.031 (hazard ratio, 2.36; 95% confidence interval, 1.08–5.16), respectively]. Treatment of MDA-MB-157 and MDA-MB-468 human basal-like breast cancer cells with TLSC702 (a GLO 1 inhibitor) and/or aurothiomalate (a PKCλ inhibitor) reduced both cell viability and tumor-sphere formation. These results suggested that GLO 1 and PKCλ were cooperatively involved in cancer progression and contributed to a poor prognosis in breast cancer. In conclusion, GLO 1 and PKCλ serve as potentially effective therapeutic targets for treatment of late-stage human breast cancer.

High SLC20A1 Expression Is Associated With Poor Prognoses in Claudin-low and Basal-like Breast Cancers

BACKGROUND/AIM

SLC20A1 has been identified as a prognostic marker in ER+ breast cancer. However, the role of SLC20A1 expression in breast cancer subtypes other than the ER+ types remains unclear.

MATERIALS AND METHODS

Genomics datasets were downloaded and analyzed, and the effect of SLC20A1 knockdown using targeted siRNA on cell viability and tumor-sphere formation was assessed.

RESULTS

SLC20A1^high patients with ER+, claudin-low or basal-like breast cancers showed poor prognoses. SLC20A1^high patients treated with radiotherapy had poor clinical outcomes. SLC20A1 knockdown suppressed the viability of MDA-MB 231 (claudin-low), MDA-MB 468 (basal-like) and MCF-7 (ER+) cells, and tumor-sphere formation by ALDH1^high cells. These results suggest that SLC20A1 is involved in cancer progression and contributes to clinical outcomes in patients with ER+, claudin-low and basal-like breast cancers.

CONCLUSION

SLC20A1 is a potential prognostic marker and therapeutic target in ER+, claudin-low and basal-like breast cancers.

High Expression of c-Met, PKCλ and ALDH1A3 Predicts a Poor Prognosis in Late-stage Breast Cancer

BACKGROUND/AIM

Co-expression of c-Met and ALDH1A3 indicates a poor prognosis in stage III-IV breast cancers and contributes to cell proliferation and tumor formation by ALDH1-positive breast CSCs. PKCλ is overexpressed and contributes to a poor prognosis in several cancers.

MATERIALS AND METHODS

A breast cancer genomics data set (METABRIC, n=2509) was downloaded and analyzed, as was the effect c-Met and PKCλ inhibitors on ALDH1^high cell viability and tumor-sphere formation.

RESULTS

c-Met expression correlates with expression of PKCλ in breast cancer. Stage III-IV breast cancer patients with c-Met^high PKCλ^high ALDH1A3^high have a poorer prognosis than patients with c-Met^low PKCλ^low ALDH1A3^low Foretinib and auranofin suppressed cell viability and tumor-sphere formation by ALDH1^high cells. These results suggest that c-Met and PKCλ are cooperatively involved in cancer progression and contribute to poor prognoses in breast cancer.

CONCLUSION

c-Met and PKCλ are potentially useful prognostic markers and therapeutic targets in late-stage breast cancer.

Glyoxalase 1 gene is highly expressed in basal-like human breast cancers and contributes to survival of ALDH1-positive breast cancer stem cells

Glyoxalase 1 (GLO1) is a ubiquitous enzyme involved in the detoxification of methylglyoxal, a cytotoxic byproduct of glycolysis that induces apoptosis. In this study, we found that GLO1 gene expression correlates with neoplasm histologic grade (χ 2 test, p = 0.002) and is elevated in human basal-like breast cancer tissues. Approximately 90% of basal-like cancers were grade 3 tumors highly expressing both GLO1 and the cancer stem cell marker ALDH1A3. ALDH1high cells derived from the MDA-MB 157 and MDA-MB 468 human basal-like breast cancer cell lines showed elevated GLO1 activity. GLO1 inhibition using TLSC702 suppressed ALDH1high cell viability as well as the formation of tumor-spheres by ALDH1high cells. GLO1 knockdown using specific siRNAs also suppressed ALDH1high cell viability, and both TLSC702 and GLO1 siRNA induced apoptosis in ALDH1high cells. These results suggest GLO1 is essential for the survival of ALDH1-positive breast cancer stem cells. We therefore conclude that GLO1 is a potential therapeutic target for treatment of basal-like breast cancers.

Correlation between c-Met and ALDH1 contributes to the survival and tumor-sphere formation of ALDH1 positive breast cancer stem cells and predicts poor clinical outcome in breast cancer

c-Met is a receptor-type tyrosine kinase, which is involved in a wide range of cellular responses such as proliferation, motility, migration and invasion. It has been reported to be overexpressed in various cancers. However, the role of c-Met in breast cancer stem cells (CSCs) still remains unclear. We herein, show that c-Met expression is significantly elevated in Basal-like type of breast cancer in comparison with other subtypes. High expression of c-Met strongly correlated with the expression of two CSC markers, ALDH1A3 and CD133 in breast cancers. In addition, breast cancers at tumor stage III-IV expressing both c-Met^high and ALDH1A3^high had poor prognosis. Furthermore, treatment with c-Met inhibitors (Crizotinib, Foretinib, PHA-665752 and Tivantinib) in MDA-MB157 cells with high c-Met protein expression resulted in significant suppression in cell viability, contrary to MDA-MB468 cells with low c-Met protein expression. These c-Met inhibitors also suppressed cell viability and tumor-sphere formation of ALDH1^high breast cancer cells with high c-Met expression. These results suggest that c-Met in ALDH1 positive CSCs seems to play an important role in breast cancer repopulation. Therefore, we conclude that c-Met is a potential therapeutic target in ALDH1 positive breast CSCs.

Evaluation of epidermal growth factor receptor mutation status in serum DNA as a predictor of response to gefitinib (IRESSA)

The aim of this study was to evaluate the usefulness of EGFR mutation status in serum DNA as a means of predicting a benefit from gefitinib (IRESSA) therapy in Japanese patients with non-small cell lung cancer (NSCLC). We obtained pairs of tumour and serum samples from 42 patients treated with gefitinib. EGFR mutation status was determined by a direct sequencing method and by Scorpion Amplification Refractory Mutation System (ARMS) technology. EGFR mutations were detected in the tumour samples of eight patients and in the serum samples of seven patients. EGFR mutation status in the tumours and serum samples was consistent in 39 (92.9%) of the 42 pairs. EGFR mutations were strong correlations between both EGFR mutation status in the tumour samples and serum samples and objective response to gefitinib (P<0.001). Median progression-free survival time was significantly longer in the patients with EGFR mutations than in the patients without EGFR mutations (194 vs 55 days, P=0.016, in tumour samples; 174 vs 58 days, P=0.044, in serum samples). The results suggest that it is feasible to use serum DNA to detect EGFR mutation, and that it's potential as a predictor of response to, and survival on gefitinib is worthy of further evaluation.

Exploratory analysis of EGFR FISH criteria in Japanese non-small cell lung cancer patients treated with gefitinib

7599

Background: In the phase III Iressa (gefitinib) Survival Evaluation in Lung cancer (ISEL) trial, high epidermal growth factor receptor (EGFR) gene copy number was a predictor of a gefitinib effect on survival in patients (pts) with refractory advanced non-small-cell lung cancer (NSCLC) (hazard ratio 0.61 vs 1.16 for high vs low copy number; p=0.045) [JCO 2006;24:5034–42]. Although EGFR mutation status may predict response to gefitinib in Japanese pts, there is insufficient data to clarify if high EGFR gene copy number assessed by fluorescence in situ hybridization (FISH) is predictive in these pts. This analysis investigated the applicability of both published Colorado FISH criteria (Colorado Univ) and new FISH criteria to Japanese NSCLC pts. Methods: 58 tumor specimens from gefitinib-treated Japanese pts were analyzed using Vysis LSI EGFR and CEP7 (chromosome 7 control) FISH probes. Specimens were classed as FISH+ or - using Colorado and exploratory (EGFR/cell; CEP7/cell; EGFR/CEP7; % of cells with various numbers of EGFR or CEP7 signals) criteria. Results: Of the 58 pts, 17 (29%) had an objective response (OR). Using Colorado criteria, OR was 50% in the 14 FISH+ pts vs 23% in the 44 FISH- pts (2-sided Fisher's exact test p=0.089). There was a trend for an association between FISH+ status and improved survival (log rank p=0.15). Defining FISH+ as specimens with =5% cells containing >5 EGFR signals, OR was significantly better among FISH+ pts vs FISH- pts (p=0.0030; 52% of the 23 FISH+ pts responding vs 14% of the 35 FISH- pts). A survival advantage was not indicated. Defining FISH+ as =74% of cells with EGFR or CEP7 loss (<2 signals) or gain (>2 signals), OR was significantly better among FISH+ pts vs FISH- pts (p=0.043; 45% of the 22 FISH+ pts responding vs 19% of the 36 FISH- pts). Association with survival had marginal significance (log rank p=0.061). Conclusions: These preliminary data have identified loss or gain of EGFR and CEP7 abnormality as promising biomarkers for response to gefitinib in Japanese NSCLC patients. Analysis of these markers for correlation with time to progression is ongoing. Investigation of these potential markers in other cohorts of patients is worthy of further evaluation.

[Table: see text]

Predictive and prognostic impact of plasma vascular endothelial growth factor levels in non-small-cell lung cancer patients treated with gefitinib

13030

Background: In non-small cell lung cancer (NSCLC), sensitivity to gefitinib is associated with activating mutations of the epidermal growth factor receptor (EGFR). Tumor samples obtained for diagnosis of NSCLC are limited and often unsuitable for analysis of mutations. Other biomarkers are thus needed. We previously reported that serum vascular endothelial growth factor (VEGF) levels were significantly lower in responders to gefitinib than non-responders. To assess levels of circulating VEGF as a predictive and prognostic marker of gefitinib treatment in NSCLC patients, we examined the associations between plasma VEGF levels before gefitinib treatment and clinical outcome. Methods: Eighty four NSCLC patients treated with gefitinib were enrolled into this investigation. Plasma VEGF levels were measured in blood samples before gefitinib administration. Patients were grouped according to VEGF level around a cut-off of 80.7 pg/ml, based on results from normal controls. Response to gefitinib was judged using RECIST guidelines. Time to progression (TTP) and overall survival (OS) following gefitinib treatment were calculated using Kaplan-Meier methods. Groups were compared using log-rank test. We evaluated the immunohistochemical expression of VEGF and EGFR mutations in tumor samples from 37 patients. Results: Response rate was significantly higher with low VEGF level than with high VEGF level (p = 0.0010). Multivariate analysis for response to gefitinib including sex, histology, smoking status, performance status and plasma VEGF level identified only low VEGF level as predictive of response to gefitinib. Low VEGF level was also correlated with prolonged median TTP (4.1 months vs. 1.1 months, p = 0.0081) and OS (11.1 months vs. 5.4 months, p = 0.0290). Multivariate analysis for survival revealed low VEGF level as associated with prolonged TTP (p = 0.0081) and OS (p = 0.0708). Plasma VEGF level was not associated with either VEGF expression or EGFR mutations of tumor tissue. Conclusions: Our results suggest that plasma VEGF levels before gefitinib treatment are predictive of response to gefitinib and prognostic of patients who receive gefitinib.

[Table: see text]

Expression of terminal deoxynucleotidyltransferase gene in a case of adult T-cell leukemia

A 37-year-old male from Kagoshima Prefecture was admitted with adult T-cell leukemia (ATL). Monoclonal integration of HTLV-1 proviral DNA was found, but the integration site was different from that of terminal deoxynucleotidyltransferase (TdT)-positive MT-1 cells (an ATL cell line). The ATL cells expressed enzymatically active TdT and exhibited 2100 b TdT mRNA, which corresponds to the thymus type of TdT mRNA. The same size of TdT mRNA was also detected in MT-1. Southern blot analyses revealed no differences in the gene structure of the promoter region of TdT genes between this ATL case and TdT-positive lymphoblastic leukemia cells. There is little possibility that cis-acting viral elements promote TdT gene expression by proviral integration. The activation of TdT gene in ATL may be mediated by other trans-acting factors.

1 alpha, 25-dihydroxyvitamin D3 enhances the up-regulation of interleukin-2 receptor (p55) by interleukin-2

The effect of 1 alpha, 25-dihydroxyvitamin D3 (1 alpha, 25(OH)2D3) on the expression of interleukin-2 (IL-2) receptor in activated T lymphocytes was examined. 1 alpha, 25(OH)2D3 enhanced the expression of IL-2 receptor (p55, Tac peptide) in phytohemagglutinin (PHA)-stimulated (3 days) human peripheral blood mononuclear cells (PBM) only in the presence of IL-2 without affecting the proliferation of the cells. This enhancement was dependent on the concentration of both IL-2 (0-1 U/ml) and 1 alpha, 25(OH)2D3(0-10(-7)M). The addition of interleukin-1 (IL-1, 0-100 U/ml), did not enhance the expression of IL-2 receptor in these cells in the presence of IL-2. Moreover, 1 alpha, 25(OH)2D3 had the same effect on two cell lines, Kit225 (an IL-2 dependent cell line established from a patient with T cell chronic lymphocytic leukemia) and YT (an IL-2 independent natural killer (NK)-like cell line from a patient with acute lymphocytic leukemia). Thus, 1 alpha, 25(OH)2D3 enhances the up-regulation of IL-2 receptor (p55) by IL-2 not only in activated T cells but also in the NK-like cell line.

Leukemic cells from some adult T-cell leukemia patients proliferate in response to interleukin-4

The proliferative response of fresh peripheral blood leukemic cells from eight adult T cell leukemia (ATL) patients to interleukin-4 (IL-4) was studied to determine the possibility that the IL-4-mediated T-cell growth pathway is involved in the cell growth of leukemic cells in ATL. Resting lymphocytes from ten normal individuals did not proliferate in response to IL-4. Leukemic cells from two ATL patients did not respond to interleukin-2 (IL-2) or IL-4. Leukemic cells from two patients did respond to IL-2, but not to IL-4. In contrast, a strong proliferative response was observed in the IL-4 culture, but not in the IL-2 culture in the remaining four patients. Chromosome analysis of mitotic cells, performed in one of four patients, confirmed that the cells dividing in response to IL-4 were leukemic cells, but not activated normal lymphocytes. These results indicate the activation of IL-4/IL-4 receptor system in leukemic cells from some ATL patients and suggest the possible involvement of the system in the proliferation of leukemic cells and the leukemogenesis in ATL.

Characteristics of the IL-2 receptor expressed on large granular lymphocytes from patients with abnormally expanded large granular lymphocytes. Implication of a non-Tac IL-2-binding peptide

Large granular lymphocytes (LGL) from four patients with abnormally expanded LGL in the peripheral blood were studied regarding their receptor for IL-2. LGL from none of the cases examined expressed Tac Ag, an Il-2R glycoprotein recognized by anti-Tac mAb. However, 125I-labeled IL-2 binding experiments demonstrated that 1400 to 2800/cell IL-2 binding sites with a single affinity (K: 0.46-1.4 nM) were expressed on LGL from the four patients. The affinity was not high but about 10-fold higher than that of the low affinity IL-2R expressed on activated normal T lymphocytes. Furthermore, LGL from the four patients proliferated in response to higher concentrations of IL-2 and these responses were not inhibited by an excess amount of anti-Tac antibody. 125I-Labeled IL-2 cross-linking studies performed in two cases revealed the predominant expression of an IL-2 binding molecule with an estimated Mr of 70,000 to 75,000. After the culture with IL-2 for 48 h, expression of a small amount of Tac Ag (p55) was induced on LGL in at least three cases. These data strongly suggested that the IL-2R expressed on LGL is functional and identical to the p70, a novel IL-2 binding peptide that has been recently identified and speculated to form the high affinity IL-2R in association with the p55.

Characteristics of the IL-2 receptor expressed on large granular lymphocytes from patients with abnormally expanded large granular lymphocytes. Implication of a non-Tac IL-2-binding peptide

Large granular lymphocytes (LGL) from four patients with abnormally expanded LGL in the peripheral blood were studied regarding their receptor for IL-2. LGL from none of the cases examined expressed Tac Ag, an Il-2R glycoprotein recognized by anti-Tac mAb. However, 125I-labeled IL-2 binding experiments demonstrated that 1400 to 2800/cell IL-2 binding sites with a single affinity (K: 0.46-1.4 nM) were expressed on LGL from the four patients. The affinity was not high but about 10-fold higher than that of the low affinity IL-2R expressed on activated normal T lymphocytes. Furthermore, LGL from the four patients proliferated in response to higher concentrations of IL-2 and these responses were not inhibited by an excess amount of anti-Tac antibody. 125I-Labeled IL-2 cross-linking studies performed in two cases revealed the predominant expression of an IL-2 binding molecule with an estimated Mr of 70,000 to 75,000. After the culture with IL-2 for 48 h, expression of a small amount of Tac Ag (p55) was induced on LGL in at least three cases. These data strongly suggested that the IL-2R expressed on LGL is functional and identical to the p70, a novel IL-2 binding peptide that has been recently identified and speculated to form the high affinity IL-2R in association with the p55.

Close association between interleukin 2 receptor mRNA expression and human T cell leukemia/lymphoma virus type I viral RNA expression in short-term cultured leukemic cells from adult T cell leukemia patients

Human T cell leukemia/lymphoma (T-lymphotropic) virus type I (HTLV-I) infection has been considered to be closely associated with the leukemogenesis of adult T cell leukemia (ATL), in which interleukin 2 (IL-2) receptors are abnormally expressed. In this study, however, Southern blot analysis revealed no gross rearrangement or obvious amplification of the IL-2 receptor gene in ATL leukemic cells, indicating that abnormal IL-2 receptor expression in ATL is not due to the structural change of its gene. Hence, we studied the expression of the IL-2 receptor and HTLV-I at the RNA level during short-term cultures of leukemic cells from 9 ATL patients. Cytoplasmic dot hybridization and Northern hybridization revealed that fresh leukemic cells from seven of nine patients expressed a small amount of IL-2 receptor mRNA but HTLV-I RNA was undetectable in all cases. After cultures for up to 7 d, both IL-2 receptor mRNA and HTLV-I RNA (including pX message) expression concomitantly increased, whereas the amounts of other cellular genes, except for beta-actin, did not. The increases in their RNA expression were inhibited by early addition (within 12 h after the beginning of the culture) of cycloheximide, indicating that these increases are mediated by newly synthesized protein(s). These results strongly suggested that IL-2 receptor expression is closely associated with HTLV-I expression in leukemic cells from ATL patients.

Increase in cytoplasmic free calcium concentration initiated by T3 antigen stimulation is imparied in adult T-cell leukemia cells

We studied the change in cytoplasmic free calcium ion concentration ([Ca2+]i) in the peripheral blood leukemic cells from adult T-cell leukemia (ATL) patients stimulated by anti-T3 (CD3) or anti-T11 (CD2) antibodies in order to see whether there is an abnormal response in the early activation processes following T3 or T11 antigen stimulation. Peripheral blood mononuclear cells (PBMC) from four T-cell chronic lymphocytic leukemia (T-CLL) patients showed a rapid and clear increase in [Ca2+]i (from 165 +/- 26 nM to more than 299 nM) when stimulated by OKT3 antibody and anti-mouse IgG antibody. This response was comparable to that of PBMC from 10 normal individuals (from 151 +/- 20 nM to 252 +/- 34 nM). In contrast, PBMC from 10 ATL patients showed only a slight increase in [Ca2+]i (from 137 +/- 21 nM to 176 +/- 32 nM) following T3 stimulation. The experiments with higher concentrations of OKT3 antibody suggested that this attenuated increase in [Ca2+]i in ATL cells was not exclusively due to impaired expression of T3 antigen. The [Ca2+]i increase in ATL cells induced by the stimulation with two anti-T11 antibodies recognizing different epitopes of the T11 antigen, however, was comparable to that of normal PBMC. The abnormal response of [Ca2+]i to the T-cell receptor/T3 antigen stimulation in ATL may be related to dysfunction or leukemogenesis of HTLV-I-infected cells.

Expression of interleukin-2 receptor on T cell chronic lymphocytic leukemia cells and their response to interleukin-2

We analyzed peripheral blood leukemic cells from six patients with T cell chronic lymphocytic leukemia (T-CLL) with monoclonal antibodies including the anti-Tac antibody, which recognizes the receptor for interleukin 2 (IL 2). The patients were divided into two groups according to the reactivity of the monoclonal antibodies. Leukemic cells from three patients with T-CLL reacted with OKT3 and T4 but not T8, whereas those from the remaining three patients reacted with OKT3 and T8 but not T4. IL 2 receptor, which is expressed on activated T cells but not on resting T cells, was preferentially expressed on T4+ T-CLL cells. The IL 2 receptor on T4+ T-CLL cells was indistinguishable from that on normal activated T cells with respect to molecular weight and downregulation by the anti-Tac antibody. Moreover, fresh T4+ T-CLL cells, but not T8+ T-CLL cells, proliferated in response to exogenous IL 2 without prior activation, and this proliferation was inhibited by the anti-Tac antibody. These results suggest that malignant growth of T4+ T-CLL cells can be regulated by IL 2 not only in vitro but also in vivo.

Dissociation of interleukin-2-mediated cell proliferation and interleukin-2 receptor upregulation in adult T-cell leukemia cells

We studied cell proliferation and interleukin-2 (IL-2) receptor upregulation mediated by exogenous IL-2 in leukemic cells from adult T-cell leukemia (ATL) patients to characterize some aspects of abnormal IL-2 receptor expression in ATL. Leukemic cells from 7 ATL patients examined showed no or very poor proliferative response to IL-2 though they expressed IL-2 receptors without any stimulation. In contrast, ATL leukemic cells cultured with IL-2 for 2 days expressed about twice as many IL-2 receptors as those of cells cultured without IL-2. Thus, in ATL leukemic cells, there seems to be a dissociation between the signal(s) for two different effects mediated by IL-2, cell proliferation and IL-2 receptor upregulation.

Interleukin-2 receptor (Tac antigen) expressed on adult T cell leukemia cells

We studied the expression of the interleukin-2 (IL-2) receptor and the proliferative response to exogenous IL-2 of peripheral blood leukemic cells from patients with adult T cell leukemia (ATL) in order to see whether IL-2 receptor expressed on ATL cells is different from normal IL-2 receptor and whether it plays a role in the neoplastic growth in ATL. Peripheral blood leukemic cells from 42 patients with ATL examined expressed IL-2 receptors that were detected by anti-Tac monoclonal antibody when examined immediately after the separation of cells or after the culture for 24 or 48 h. The number of anti-Tac binding sites ranged from 3,100 to 11,400 in fresh cells and from 3,600 to 96,000/cell in short-term cultured leukemic cells, whereas phytohemagglutinin-P (PHA-P)-stimulated normal T cells exhibited 6,900-35,000 anti-Tac binding sites per cell. ATL-derived and human T cell leukemia/lymphoma virus, type I (HTLV-I)-infected cell lines such as MT-1 and Hut102 expressed a much higher number of anti-Tac binding sites. Leukemic cells from 15 patients with ATL examined showed no or very poor proliferative response to various concentrations of immunoaffinity-purified IL-2, although they expressed Tac antigen (Ag). Radiolabeled IL-2 binding experiments demonstrated that ATL leukemic cells could bind IL-2, and they expressed both high and low affinity IL-2 receptors, although the number of high affinity IL-2 receptor was much less than that of low affinity IL-2 receptor and that of anti-Tac binding sites. In contrast, leukemic T cells from a patient with T cell chronic lymphocytic leukemia (CLL), in whom HTLV-I infection was not demonstrated, responded as well as PHA-P-stimulated normal T cells, and their IL-2 receptors, unlike ATL cells, were modulated (down regulated) by anti-Tac antibody. No differences were noted between ATL cells and normal activated T cells in one-dimensional sodium dodecyl sulfate polyacrylamide gel electrophoresis analysis of the IL-2 receptor. Thus, leukemic cells in ATL spontaneously and continuously express IL-2 receptor, which appears to be abnormally regulated and unresponsive to IL-2. These results, taken together with those on normal IL-2 receptors on HTLV-I-negative T-CLL cells, suggest that abnormal expression of the IL-2 receptor in ATL is closely associated with HTLV-I infection and may play a role in the neoplastic growth of ATL cells.

Acute leukemia with two cell populations of lymphoblasts and monoblasts

A 46-year-old man had acute leukemia with two cell populations of lymphoblasts and monoblasts (L1 and M5-b in FAB classification, respectively), which were characterized by morphological, cytochemical and cell marker studies. At the time of diagnosis about 80% blasts were terminal deoxynucleotidyl transferase (TdT) positive lymphoid cells, while the rest were TdT negative monocytoid cells. After induction chemotherapy of vindesine and prednisolone for 15 days, almost all blasts were TdT negative monocytoid cells. Therefore, an additional course of the chemotherapy with the protocol for acute nonlymphocytic leukemia was given and one month later the patient achieved complete remission.

A case of 17 alpha-hydroxylase deficiency syndrome associated with right adrenal tumor

A 35-year-old woman, who had been hypertensive for about 17 years and had lacked menarche, showed hypokalemia, low plasma cortisol and aldosterone levels, suppressed renin activity, and marked elevation of plasma corticosterone. The patient was diagnosed as having 17 alpha-hydroxylase deficiency from functional studies. In addition, a right adrenal tumor was found by adrenal venography. Adrenal venous sampling showed that this tumor might be secreting corticosterone and possibly also deoxycorticosterone (DOC). The genotype was 46,XY, so she was diagnosed as having male pseudohermaphroditism. Right adrenalectomy and contralateral adrenal biopsy were done. The retained testicles were removed. Dexamethasone administration normalized the blood pressure and serum potassium. This is the first report of 17 alpha-hydroxylase deficiency with a right adrenal tumor.

Asymptomatic normotensive primary aldosteronism. Case report

We report a case of primary aldosteronism in a 30-year-old woman without hypertension or any other characteristic symptoms. The condition was first suspected by hypokalemia (2.6 mEq/liter), which was incidentally found by routine checkup. There was evidence of suppressed plasma renin activity (PRA) and elevated plasma aldosterone levels. However, the blood pressure never reached a hypertensive level, and the circulating blood volume was within a normal range. A functioning right adrenal tumor was diagnosed by adrenal scintigraphy, computerized x-ray tomography, and adrenal venography. Adrenal venous catheterization suggested an aldosteronoma, which was confirmed by lateralized hypersecretion of aldosterone. After removal of the benign adenoma, the biochemical abnormalities were corrected, yet the blood pressure remained much the same. Hypertension is not necessarily a sign of primary aldosteronism.