ALDH/CD44 identifies uniquely tumorigenic cancer stem cells in salivary gland mucoepidermoid carcinomas

Prognostic factors of palatal mucoepidermoid carcinoma: a retrospective analysis based on a double-center study

Mucoepidermoid carcinoma (MEC) of the palate is a common malignancy of minor salivary glands. This study was designed to identify the prognostic factors for MEC of the palate. The medical records of patients diagnosed with MEC of the palate who visited the Department of Oral and Maxillofacial Surgery at Nanjing Stomatological Hospital and the Department of Stomatology at Central Hospital of Xuzhou were retrospectively studied. The prognostic factors were determined using a Cox proportional hazards model. Furthermore, the expression of cancer stem cell (CSC) markers CD44, CD133, Nanog and Sox2 were detected in neoplastic samples of these patients by immunohistochemistry. As a result, both univariate analysis and multivariate analysis proved a high histological grade and an advanced tumor stage as negative prognostic factors for overall survival. By immunohistochemistry staining and survival analysis, a combination of CD44/CD133/SOX2 was found to have the strongest prognostic value for palatal MEC patients. In conclusion, the proposed nomogram which include histological grade and tumor stage along with cancer stem cell markers provides a more accurate long-term prediction for palatal MEC patients.

Immunohistochemical Expression of CD56 and ALDH1 in Common Salivary Gland Tumors

INTRODUCTION

Natural killer (NK) cells, of which CD₅₆ is a specific marker, play an important role in host defense against tumors. Cancer stem cells, of which aldehyde dehydrogenase isoform 1 (ALDH₁) is an immunohistochemical marker, are a group of tumorigenic cells which are involved in migration and tumor recurrences. We aimed to evaluate the expression of ALDH₁ and CD₅₆ in common salivary gland tumors, as well as their relationship with each other and with a number of clinicopathologic factors.

MATERIALS AND METHODS

Forty-five paraffin blocks of salivary gland tumors (pleomorphic adenoma, mucoepidermoid carcinoma and adenoid cystic carcinoma, 15 samples each) were selected. Malignant tumors were classified into two groups: low-grade (including mucoepidermoid carcinoma grade I) and high-grade (including mucoepidermoid carcinoma grade III and adenoid cystic carcinoma). Immunohistochemical staining for ALDH₁ and CD₅₆ markers was performed. Data were analyzed using SPSS (20) and the Chi-square test.

RESULTS

CD₅₆ expression was significantly higher in benign and high-grade malignant tumors (P=0.01). ALDH₁ overexpressed in all three salivary tumors, but not to statistically significant degree (P=0.54). There was no statistically significant correlation between ALDH₁ and CD₅₆ expression with demographic factors (age, gender, or location of tumor; P>0.05).

CONCLUSION

It appears that the number of NK cells and their function change in different types of salivary gland tumors (benign/malignant) and stroma. NK cells are important components of the anti-tumor system; therefore immune dysfunction is associated with tumor progression in tumors of the salivary gland. ALDH₁ overexpression suggests its role in tumorogenesis, but ALDH₁ is not involved in the morphogenesis of salivary gland tumors.

Therapeutic Inhibition of the MDM2-p53 Interaction Prevents Recurrence of Adenoid Cystic Carcinomas

Purpose: Conventional chemotherapy has modest efficacy in advanced adenoid cystic carcinomas (ACC). Tumor recurrence is a major challenge in the management of ACC patients. Here, we evaluated the antitumor effect of a novel small-molecule inhibitor of the MDM2-p53 interaction (MI-773) combined with cisplatin in patient-derived xenograft (PDX) ACC tumors.Experimental Design: Therapeutic strategies with MI-773 and/or cisplatin were evaluated in SCID mice harboring PDX ACC tumors (UM-PDX-HACC-5) and in low passage primary human ACC cells (UM-HACC-2A, -2B, -5, -6) in vitro The effect of therapy on the fraction of cancer stem cells (CSC) was determined by flow cytometry for ALDH activity and CD44 expression.Results: Combined therapy with MI-773 with cisplatin caused p53 activation, induction of apoptosis, and regression of ACC PDX tumors. Western blots revealed induction of MDM2, p53 and downstream p21 expression, and regulation of apoptosis-related proteins PUMA, BAX, Bcl-2, Bcl-x_L, and active caspase-9 upon MI-773 treatment. Both single-agent MI-773 and MI-773 combined with cisplatin decreased the fraction of CSCs in PDX ACC tumors. Notably, neoadjuvant MI-773 and surgery eliminated tumor recurrences during a postsurgical follow-up of more than 300 days. In contrast, 62.5% of mice that received vehicle control presented with palpable tumor recurrences within this time period (P = 0.0097).Conclusions: Collectively, these data demonstrate that therapeutic inhibition of MDM2-p53 interaction by MI-773 decreased the CSC fraction, sensitized ACC xenograft tumors to cisplatin, and eliminated tumor recurrence. These results suggest that patients with ACC might benefit from the therapeutic inhibition of the MDM2-p53 interaction. Clin Cancer Res; 23(4); 1036-48. ©2016 AACR.

Cancer stem cell mediated acquired chemoresistance in head and neck cancer can be abrogated by aldehyde dehydrogenase 1 A1 inhibition

Chemoresistance leading to disease relapse is one of the major challenges to improve outcome in head and neck cancers. Cancer Stem Cells (CSCs) are increasingly being implicated in chemotherapy resistance, this study investigates the correlation between CSC behavior and acquired drug resistance in in vitro cell line models. Cell lines resistant to Cisplatin (Cal-27 CisR, Hep-2 CisR) and 5FU (Cal-27 5FUR) with high Resistance Indices (RI) were generated (RI ≥ 3) by short-term treatment of head and neck squamous cell carcinoma (HNSCC) cell lines with chemotherapeutic drugs (Cisplatin, Docetaxel, 5FU), using a dose-incremental strategy. The cell lines (Cal-27 DoxR, Hep-2 DoxR, Hep-2 5FUR) that showed low RI, nevertheless had a high cross resistance to Cisplatin/5FU (P < 0.05). Cal-27 CisR and DoxR showed 12-14% enrichment of CD44+ cells, while CisR/5FUR showed 4-6% increase in ALDH1A1+ cells as compared to parental cells (P < 0.05). Increased expression of stem cell markers (CD44, CD133, NOTCH1, ALDH1A1, OCT4, SOX2) in these cell lines, correlated with enhanced spheroid/colony formation, migratory potential, and increased in vivo tumor burden (P < 0.05). Inhibition of ALDH1A1 in Cal-27 CisR led to down regulation of the CSC markers, reduction in migratory, self-renewal and tumorigenic potential (P < 0.05) accompanied by an induction of sensitivity to Cisplatin (P < 0.05). Further, ex vivo treatment of explants (n = 4) from HNSCC patients with the inhibitor (NCT-501) in combination with Cisplatin showed a significant decrease in proliferating cells as compared to individual treatment (P = 0.001). This study hence suggests an ALDH1A1-driven, CSC-mediated mechanism in acquired drug resistance of HNSCC, which may have therapeutic implications. © 2016 Wiley Periodicals, Inc.

Activity of aldehyde dehydrogenase in B-cell and plasma cell subsets of monoclonal gammopathy patients and healthy donors

BACKGROUND

Aldehyde dehydrogenase (ALDH) is highly active in physiological stem cells as well as in tumor-initiating cells of some malignancies including multiple myeloma (MM). Finding higher activity of ALDH in some cell subsets in monoclonal gammopathies (MG) could identify potential source of myeloma-initiating cells (MICs).

METHODS

Bone marrow of 12 MM, 9 monoclonal gammopathy of undetermined significance (MGUS), and 10 healthy donors (HD) were analyzed by flow cytometry. ALDH activity of B-cells and plasma cells (PC) was analyzed using Aldefluor.

RESULTS

Similar changes of ALDH activity were found during B-cell development in HD and MG. Decreasing of ALDH activity from immature to naïve B-cells was found. In postgerminal stages, the activity started to increase, and in PCs, the ALDH activity was the same as in immature B-cells. Increased ALDH activity of all PC subsets compared to naïve B-cells was found in MM as well as in HD, while in MGUS, only CD19^- PCs have higher ALDH activity. In HD, ALDH activity was higher in CD19⁺ PCs compared with MG.

CONCLUSIONS

Our results indicate that changes of ALDH activity are the natural phenomenon in B-cell development; thus, high ALDH activity as a single marker is not appropriate for MICs identification.

Lability and diversity of circadian rhythms of cotton rats Sigmodon hispidus

Tumor initiating cells (TIC) have been suggested as a mechanism for driving chemoresistance and tumor recurrence in human cancers including triple negative breast cancer (TNBC). Significant progress has been made in targeting TICs. However, methods for simultaneously targeting heterogeneous TIC populations are lacking. In this study, we found that treating TNBC cells with chemotherapeutic agents led to a significant accumulation of the ALDH⁺ TIC population. Treating TNBC cells with a disulfiram and copper mixture (DSF/Cu) specifically decreased the ALDH⁺ TIC population and treatment with BKM120, a pan-PI3K inhibitor, significantly decreased the CD44⁺/CD24⁻ TIC population. Furthermore, treatment with DSF/Cu or BKM120 induced higher levels of apoptosis in ALDH⁺ or CD44⁺/CD24⁻ populations, respectively, than in bulk tumor cells. Combining DSF/Cu and BKM120 treatment simultaneously decreased the ALDH⁺ and CD44⁺/CD24⁻ TICs. Using a TNBC tumor xenograft mouse model, we found that DSF/BKM in combination with Taxol significantly reduced the tumor burden and delayed tumor recurrence compared to Taxol treatment alone. Our study is the first of its kind to use two different drugs to abolish two major TIC subtypes simultaneously and inhibit tumor recurrence. These results lay a foundation for developing a novel therapy that can improve chemotherapeutic efficacy.