Evaluation of Polo-like kinase 1 as a potential therapeutic target in Merkel cell carcinoma

Allyl isothiocyanate inhibits cell migration and invasion in human gastric cancer AGS cells via affecting PI3K/AKT and MAPK signaling pathway in vitro

Metastasis is commonly occurred in gastric cancer, and it is caused and responsible for one of the major cancer-related mortality in gastric cancer patients. Allyl isothiocyanate (AITC), a natural product, exhibits anticancer activities in human many cancer cells, including gastric cancer. However, no available report shows AITC inhibits gastric cancer cell metastasis. Herein, we evaluated the impact of AITC on cell migration and invasion of human gastric cancer AGS cells in vitro. AITC at 5-20 μM did not induce significant cell morphological damages observed by contrast-phase microscopy but decreased cell viability assayed by flow cytometry. After AGS cells were further examined by atomic force microscopy (AFM), which indicated AITC affected cell membrane and morphology in AGS cells. AITC significantly suppressed cell motility examined by scratch wound healing assay. The results of the gelatin zymography assay revealed that AITC significantly suppressed the MMP-2 and MMP-9 activities. In addition, AITC suppressed cell migration and invasion were performed by transwell chamber assays at 24 h in AGS cells. Furthermore, AITC inhibited cell migration and invasion by affecting PI3K/AKT and MAPK signaling pathways in AGS cells. The decreased expressions of p-AKTThr308 , GRB2, and Vimentin in AGS cells also were confirmed by confocal laser microscopy. Our findings suggest that AITC may be an anti-metastasis candidate for human gastric cancer treatment.

An Investigation of Structure-Activity Relationships and Cell Death Mechanisms of the Marine Alkaloids Discorhabdins in Merkel Cell Carcinoma Cells

A library of naturally occurring and semi-synthetic discorhabdins was assessed for their effects on Merkel cell carcinoma (MCC) cell viability. The set included five new natural products and semi-synthetic compounds whose structures were elucidated with NMR, HRMS, and ECD techniques. Several discorhabdins averaged sub-micromolar potency against the MCC cell lines tested and most of the active compounds showed selectivity towards virus-positive MCC cell lines. An investigation of structure-activity relationships resulted in an expanded understanding of the crucial structural features of the discorhabdin scaffold. Mechanistic cell death assays suggested that discorhabdins, unlike many other MCC-active small molecules, do not induce apoptosis, as shown by the lack of caspase activation, annexin V staining, and response to caspase inhibition. Similarly, discorhabdin treatment failed to increase MCC intracellular calcium and ROS levels. In contrast, the rapid loss of cellular reducing potential and mitochondrial membrane potential suggested that discorhabdins induce mitochondrial dysfunction leading to non-apoptotic cell death.

Tension-free thyroidectomy (TFT): initial report

The safety of thyroid surgery in terms of recurrent laryngeal nerve palsy and hypoparathyroidism has increased over the last decade. In this study, we present a new method of tension-free thyroidectomy (TFT), which could be used to further decrease the complication rate after a thyroidectomy. The procedure is based on the medial approach to the recurrent laryngeal nerve and the parathyroid glands after the division of the isthmus and successive complete dissection of Berry's ligament. In total, 92 patients (127 nerves at risk) underwent "tension-free thyroidectomy" (TFT) between August and November 2021. All the procedures were performed by a single surgeon at Saint Petersburg State University Hospital. There were 74 females and 18 male patients (ratio 4.1:1) with a mean age of 46.9 (range from 17 to 74). A lobectomy was carried out in 57 (62%) patients and a total thyroidectomy in 35 (38%). In 27 cases, patients additionally underwent central and/or lateral neck dissection. Indications for surgery were papillary carcinoma (N = 34), medullary cancer (N = 2), follicular neoplasia (N = 43), Grave's disease (N = 9), multinodular toxic goiter (N = 3), and multinodular nontoxic goiter (N = 1). Mean thyroid volume was 24.6 ml (ranged 12-70 ml). Intraoperative neuromonitoring was used in all the cases (5 mA). Translaryngeal ultrasound (TLUS) or direct laryngoscopy were routinely used prior and after surgery to evaluate vocal cords mobility. Calcium and parathormone levels were measured in patients after thyroidectomy on the first, 14th and 30th postoperative days. No recurrent laryngeal nerve palsy was observed. One patient exhibited hypoparathyroidism which was resolved in 2 weeks using substitution therapy with calcium and alfacalcidol. The mean operating time for lobectomy was 54 ± 14 min (range: 30-95 min) and for total thyroidectomy 99 ± 28 min (range: 55-158 min). There was no conversion to the conventional lateral-to-medial approach. TFT can be considered a safe and feasible operation. Comparative (randomized studies) with conventional dissection technique should be performed to investigate the hypothesis that this approach can provide a lower complication rate.

Radiosensitization of Non-Small Cell Lung Cancer Cells by the Plk1 Inhibitor Volasertib Is Dependent on the p53 Status. Cancers (Basel). 2019;11. [PMID: 31795121 PMCID: PMC6966428 DOI: 10.3390/cancers11121893]

Polo-like kinase 1 (Plk1), a master regulator of mitotic cell division, is highly expressed in non-small cell lung cancer (NSCLC) making it an interesting drug target. We examined the in vitro therapeutic effects of volasertib, a Plk1 inhibitor, in combination with irradiation in a panel of NSCLC cell lines with different p53 backgrounds. Pretreatment with volasertib efficiently sensitized p53 wild type cells to irradiation. Flow cytometric analysis revealed that significantly more cells were arrested in the G₂/M phase of the cell cycle after the combination therapy compared to either treatment alone (p < 0.005). No significant synergistic induction of apoptotic cell death was observed, but, importantly, significantly more senescent cells were detected when cells were pretreated with volasertib before irradiation compared to both monotherapies alone (p < 0.001), especially in cells with functional p53. Consequently, while most cells with functional p53 showed permanent growth arrest, more p53 knockdown/mutant cells could re-enter the cell cycle, resulting in colony formation and cell survival. Our findings assign functional p53 as a determining factor for the observed radiosensitizing effect of volasertib in combination with radiotherapy for the treatment of NSCLC.

A PLK1 kinase inhibitor enhances the chemosensitivity of cisplatin by inducing pyroptosis in oesophageal squamous cell carcinoma

BACKGROUND

Targeting PLK1 has recently been proven as a viable therapeutic strategy against oesophageal squamous cell carcinom (ESCC). Therefore, this study aimed to explore whether the PLK1 inhibitor BI2536 is able to sensitize ESCC cells to cisplatin (DDP) and determine the underlying mechanisms.

METHODS

Viability, clonogenicity, cell cycle distribution and apoptosis were assessed in ESCC cells treated with BI2536 or DDP alone or in combination. Checkpoint activation was examined by immunoblotting and immunohistochemistry. Xenograft model was used to assess the efficacy of the co-treatment. The expression level of GSDME in tissue samples were examined by immunohistochemistry.

FINDINGS

We found that the combination of BI2536 and DDP was synergistic in ESCC cells, which induced pyroptosis in ESCC cells at low doses. Mechanistic studies revealed that BI2536 significantly induced DNA damage and impaired the DNA damage repair pathway in DDP-treated cells both in vitro and in vivo. Interestingly, we found that co-treatment with BI2536 and DDP induced pyroptosis in ESCC cells depending on the caspase-3/GSDME pathway. Importantly, our study found that GSDME was more highly expressed in tumour tissue than that in normal adjacent tissues, and could serve as a prognostic factor.

INTERPRETATION

BI2536 sensitizes ESCC cells to DDP by inhibiting the DNA damage repair pathway and inducing pyroptosis, which provides new information for understanding pyroptosis. Our study also reveals that the PLK1 inhibitor BI2536 may be an attractive candidate for ESCC targeted therapy, especially when combined with DDP for treating the GSDME overexpression subtype. FUND: National 973 Program and National Natural Science Fundation of China.

ELMO3 - a Negative Prognostic Marker in Minor Salivary Gland Carcinoma

Engulfment and cell motility 3 protein (ELMO3) is a protein that is involved in cell migration and promotes the remodeling of the cytoskeleton. Moreover, it is described as a prognostic marker in several cancers. The aim of this study was to evaluate ELMO3 expression in patients with minor salivary gland carcinoma. The expression of ELMO3 was examined by immunohistochemistry. The intensity of staining was evaluated and data was correlated to clinical outcome. Forty-six patients with complete clinical data were included into statistical analysis. ELMO3 expression was observed in 85% of the cases. High staining intensity of ELMO3 correlated with a significantly worse disease free survival (p = .0495) and a higher recurrence rate (p = .0071). In conclusion, it is still difficult to predict the clinical outcome of patients with minor salivary gland carcinoma. Evaluation of ELMO3 might serve as a clinical prognostic marker in future.

AZD5582, an IAP antagonist that leads to apoptosis in head and neck squamous cell carcinoma cell lines and is eligible for combination with irradiation

CONCLUSION

On the one hand, AZD5582, an inhibitor of inhibitor of apoptosis family proteins (IAP), leads to cellular growth arrest and induction of apoptosis in head and neck squamous cell carcinoma (HNSCC) cell lines. On the other hand, it is a viable candidate for combination therapy with irradiation.

OBJECTIVES

The aim and purpose of this study was to evaluate the effects of AZD5582 on HNSCC cell lines.

METHODS

HNSCC cell lines SCC25, Cal27, and FaDu were used for all cell culture experiments. Proliferation assays were used to assess a potential inhibitory effect of AZD5582 and a combination therapy of the IAP inhibitor and irradiation. Colony forming assays were used to determine long-term effects of a combined treatment. Apoptosis was measured via flow cytometry and wound-healing assays were performed.

RESULTS

All three cell lines showed a dose-dependent cytotoxic effect after treatment with AZD5582. It was possible to observe a synergistic and additive effect after short-term treatment of AZD5582 and irradiation in Ca27 and FaDu cells, respectively. All test cell lines showed a significant inhibition of colony formation after combined treatment. Treatment of AZD5582 resulted in apoptosis in SCC25, Cal27, and FaDu cells.

ELMO3 expression indicates a poor prognosis in head and neck squamous cell carcinoma - a short report

PURPOSE

Previously, the engulfment and cell motility 3 (ELMO3) protein has been reported to be involved in cell migration and cytoskeletal remodeling. As of yet, nothing is known about the role of ELMO3 in head and neck squamous cell carcinoma (HNSCC). The purpose of this study was to asses ELMO3 expression in postoperatively irradiated HNSCC patients and to evaluate a possible correlation between this expression and patient survival.

METHODS

125 postoperatively irradiated HNSCC patients were included in this study. ELMO3 expression was assessed using immunohistochemistry (IHC). The expression of ELMO3 in the respective HNSCC tumor tissues and its lymph node metastases was correlated with patient survival using Kaplan-Meier curve analyses.

RESULTS

Through IHC, ELMO3 expression was detected in 71.2% of the HNSCC cases tested. We found significantly increased overall and disease-free survival rates and decreased recurrence rates in patients with no detectable ELMO3 expression. In reverse, we found that ELMO3 expression served as an independent marker for a decreased overall and disease-free survival.

CONCLUSION

Our data indicate that in the surgically treated and postoperatively irradiated patients tested, ELMO3 expression serves as a predictive marker for reduced survival.

Overexpression of DCLK1 is predictive for recurrent disease in major salivary gland malignancies

Salivary gland carcinomas are a rare malignancy. Therefore, little is known about biomarkers and cancer stem cells in salivary gland malignancies. Double cortin-like kinase 1 (DCLK1) is a promising therapeutic target and cancer stem cell marker, predominantly investigated in pancreatic and colorectal cancer. The purpose of this study was to investigate the expression of DCLK1 in major and minor salivary gland carcinomas and its influence on survival. We examined a total of 80 patients with major or minor salivary gland cancer in this retrospective study. Immunohistochemistry with anti-DCLK1 antibody was applied to assess the expression of DCLK1. Moreover, we evaluated the impact of DCLK1 on overall and disease-free survival. DCLK1 expression could be detected in 66.3 % of all examined cases. Overexpression of DCLK1 was associated with reduced overall and disease-free survival in patients with major salivary gland cancer. Disease-free survival reached statistical significance (p = 0.0107). However, expression of DCLK1 had no influence on survival in patients with minor salivary gland cancer. Since treatment of recurrent disease in oncologic patients is utterly challenging, DCLK1 may be a promising prognostic biomarker that helps to identify patients with a high risk for recurrence of major salivary gland carcinoma.