Chk2 deficiency alleviates irradiation-induced taste dysfunction by inhibiting p53-dependent apoptosis

Long noncoding RNA LINC00173 induces radioresistance in nasopharyngeal carcinoma via inhibiting CHK2/P53 pathway

Radiotherapy is the backbone of nasopharyngeal carcinoma (NPC), nearly 11-17% NPC patients suffered local relapse and 18-37% suffered distant metastasis mainly due to radioresistance. Therefore, the key of improving patients' survivals is to investigate the mechanism of radioresistance. In this study, we revealed that the expression level of long intergenic nonprotein coding RNA 173 (LINC00173) was significantly increased in the radioresistant NPC patients' tumour tissues compared with the radiosensitive patients by RNA-sequencing, which also predict poor prognosis in NPC. Overexpression of LINC00173 induced radioresistance of NPC cells in vitro and in vivo. Mechanistically, LINC00173 bound with checkpoint kinase 2 (CHK2) in nucleus, and impaired the irradiation-induced CHK2 phosphorylation, then suppressed the activation of P53 signalling pathway, which eventually inhibiting apoptosis and leading to radioresistance in NPC cells. In summary, LINC00173 decreases the occurrence of apoptosis through inhibiting the CHK2/P53 pathway, leads to NPC radioresistance and could be considered as a novel predictor and therapeutic target in NPC.

Effect of nutritional status before radiotherapy on radiation-induced acute toxicities in patients with nasopharyngeal carcinoma

BACKGROUND

To investigate the effect of nutritional status on radiation-induced acute toxicities in nasopharyngeal carcinoma (NPC) patients before radiotherapy.

METHODS

Nutritional status of 228 patients with NPC who received intensity-modulated radiotherapy was retrospectively analyzed by modified nutrition index (m-NI). Cumulative grading score of six common acute toxicities were defined as total score for acute toxicities.

RESULTS

M-NI ≤6 is a risk factor for xerostomia (p = 0.016, OR = 0.208, 95% CI 0.058-0.743), oral mucositis (p = 0.016, OR = 0.287, 95% CI 0.104-0.793), dysgeusia (p = 0.001, OR = 0.028, 95% CI 0.004-0.217), and dysphagia (p = 0.015, OR = 0.251, 95% CI 0.083-0.764) as well in patients with NPC. Total score of radiation-induced acute toxicities of patients with malnutrition (13.6 ± 1.7) was significantly higher than that of patients with normal nutrition (12.0 ± 2.4) (t = -5.464, p < 0.001).

CONCLUSIONS

NPC patients with malnutrition before radiotherapy develop more serious dysgeusia, oral mucositis, dysphagia, and xerostomia after intensity-modulated radiotherapy.

Mechanisms of microRNA action in rectal cancer radiotherapy

ABSTRACT

Preoperative neoadjuvant chemoradiotherapy, combined with total mesorectal excision, has become the standard treatment for advanced localized rectal cancer (RC). However, the biological complexity and heterogeneity of tumors may contribute to cancer recurrence and metastasis in patients with radiotherapy-resistant RC. The identification of factors leading to radioresistance and markers of radiosensitivity is critical to identify responsive patients and improve radiotherapy outcomes. MicroRNAs (miRNAs) are small, endogenous, and noncoding RNAs that affect various cellular and molecular targets. miRNAs have been shown to play important roles in multiple biological processes associated with RC. In this review, we summarized the signaling pathways of miRNAs, including apoptosis, autophagy, the cell cycle, DNA damage repair, proliferation, and metastasis during radiotherapy in patients with RC. Also, we evaluated the potential role of miRNAs as radiotherapeutic biomarkers for RC.

The Etiologies and Considerations of Dysgeusia: A Review of Literature

BACKGROUND

Dysgeusia is a prevalent qualitative gustatory impairment that may affect food intake and quality of life. The facial (VII), glossopharyngeal (IX), and vagus (X) nerves are the three cranial nerves responsible for sensing taste. Typically, dysgeusia is considered a general term for all taste disorders. In addition, dysgeusia may be a symptom of underlying systemic conditions such as diabetes mellitus, chronic kidney disease, respiratory infections, and nutritional deficiencies. Various subjective and objective diagnostic approaches are available to aid clinicians, each with its own set of benefits and drawbacks.

HIGHLIGHTS

Taste impairment can lead to a lack of enjoyment while eating, food aversion, and malnutrition, resulting in a decrease in the quality of life and loss of muscle mass. Therefore, the present review aims to address the probable etiologies, diagnostic aids, and management of dysgeusia. A broad search for studies was conducted using PubMed, Web of Science, Scopus, and Google Scholar. In addition, relevant studies found in the references of the selected articles were also studied.

CONCLUSION

Oral health care providers should be aware of the possible etiologies of dysgeusia, diagnostic tools, and treatment options. Accurate diagnosis of the cause of taste dysfunction has a significant impact on the management of taste impairment.

Molecular and Neural Mechanism of Dysphagia Due to Cancer

Cancer is one of the most common causes of death worldwide. Along with the advances in diagnostic technology achieved through industry–academia partnerships, the survival rate of cancer patients has improved dramatically through treatments that include surgery, radiation therapy, and pharmacotherapy. This has increased the population of cancer “survivors” and made cancer survivorship an important part of life for patients. The senses of taste and smell during swallowing and cachexia play important roles in dysphagia associated with nutritional disorders in cancer patients. Cancerous lesions in the brain can cause dysphagia. Taste and smell disorders that contribute to swallowing can worsen or develop because of pharmacotherapy or radiation therapy; metabolic or central nervous system damage due to cachexia, sarcopenia, or inflammation can also cause dysphagia. As the causes of eating disorders in cancer patients are complex and involve multiple factors, cancer patients require a multifaceted and long-term approach by the medical care team.

Radiation-induced neuropathies in head and neck cancer: prevention and treatment modalities

Head and neck cancer (HNC) is the sixth most common human malignancy with a global incidence of 650,000 cases per year. Radiotherapy (RT) is commonly used as an effective therapy to treat tumours as a definitive or adjuvant treatment. Despite the substantial advances in RT contouring and dosage delivery, patients suffer from various radiation-induced complications, among which are toxicities to the nervous tissues in the head and neck area. Radiation-mediated neuropathies manifest as a result of increased oxidative stress-mediated apoptosis, neuroinflammation and altered cellular function in the nervous tissues. Eventually, molecular damage results in the formation of fibrotic tissues leading to susceptible loss of function of numerous neuronal substructures. Neuropathic sequelae following irradiation in the head and neck area include sensorineural hearing loss, alterations in taste and smell functions along with brachial plexopathy, and cranial nerves palsies. Numerous management options are available to relieve radiation-associated neurotoxicities notwithstanding treatment alternatives that remain restricted with limited benefits. In the scope of this review, we discuss the use of variable management and therapeutic modalities to palliate common radiation-induced neuropathies in head and neck cancers.

LncRNA H19 Knockdown in Human Amniotic Mesenchymal Stem Cells Suppresses Angiogenesis by Associating with EZH2 and Activating Vasohibin-1

Human amniotic mesenchymal stem cells (HAMSCs) are promising seed cells with great advantages in promoting angiogenesis. However, the mechanisms underlying angiogenesis facilitated by HAMSCs are still unclear. Long noncoding RNA H19 is involved in many biological processes, such as enhancing angiogenesis and proliferation, invasion, and migration of cancer cells. In this study, we constructed HAMSCs of stable low-expression H19 (HAMSC-shH19) and the scramble control (HAMSC-shNC) using lentiviral vectors, and in a three-dimensional coculture with human umbilical vein endothelial cells (HUVECs) to investigate the effect of H19 knockdown in HAMSCs on angiogenesis. Our results demonstrated that H19 knockdown significantly inhibited the angiogenic function of HAMSCs at an early stage in vitro and in vivo. The results of CCK8 and transwell assays demonstrated that the conditioned medium secreted by HAMSCs reduced proliferation and migration of HUVECs after downregulating H19. The angiogenesis factors expressed and secreted by HAMSC-shH19 were decreased compared with those secreted by the control, while angiogenesis inhibitors were elevated. Furthermore, we conducted chromatin immunoprecipitation and RNA-binding protein immunoprecipitation assays and found that H19 could interact with the histone methyltransferase Enhancer of Zeste homolog 2 (EZH2) and that H19 knockdown inhibited the ability of EZH2 to recruit methyl groups to the promoter region of the angiogenesis inhibitor gene vasohibin-1 (VASH1), thus increasing VASH1 expression and secretion of HAMSCs, suppressing angiogenesis. In summary, our study identified H19 as an important regulator in HAMSCs for promoting angiogenesis, which would help to construct ideal gene-modified seed cells to enhance angiogenesis in regenerative medicine.