Low mitochondrial DNA copy number induces chemotherapy resistance via epithelial-mesenchymal transition by DNA methylation in esophageal squamous cancer cells.

BACKGROUND: Esophageal squamous cell carcinoma (ESCC) is one of the most severe cancers and is characterized by chemotherapy resistance and poor prognosis associated with epithelial-mesenchymal transition (EMT). In a previous study, a low mitochondrial DNA (mtDNA) copy number was associated with poorer prognosis and induced EMT in ESCC. However, the detailed mechanism related to mtDNA copy number and EMT is unclear. The aim of this study was to clarify the mechanism by which a change in mtDNA copy number contributes to EMT and to examine treatment of chemotherapy resistance in ESCC. METHODS: The association between low mtDNA copy number and chemotherapy resistance was investigated using specimens from 88 patients who underwent surgery after neoadjuvant chemotherapy. Then, the mtDNA content of human ESCC cell lines, TE8 and TE11, was depleted by knockdown of mitochondrial transcription factor A expression. The present study focused on modulation of mitochondrial membrane potential (MMP) and DNA methylation as the mechanisms by which mtDNA copy number affects EMT. mRNA and protein expression, chemotherapy sensitivity, proliferation, MMP and DNA methylation were evaluated, and in vitro and in vivo assays were conducted to clarify these mechanisms. RESULTS: ESCC patients with decreased mtDNA copy number who underwent R0 resection after neoadjuvant chemotherapy had significantly worse pathological response and recurrence-free survival. Additionally, low mtDNA copy number was associated with resistance to chemotherapy in vitro and in vivo. mtDNA controlled MMP, and MMP depolarization induced EMT. Depletion of mtDNA and low MMP induced DNA methylation via a DNA methylation transcription factor (DNMT), and a DNMT inhibitor suppressed EMT and improved chemotherapy sensitivity in mtDNA-depleted ESCC cells, as shown by in vitro and in vivo assays. CONCLUSION: This study showed that decreased mtDNA copy number induced EMT via modulation of MMP and DNA methylation in ESCC. Therapeutic strategies increasing mtDNA copy number and DNMT inhibitors may be effective in preventing EMT and chemosensitivity resistance.

Postoperative solitary liver metastasis from esophageal squamous cell carcinoma achieving a clinical complete response to chemotherapy with cisplatin and 5-fluorouracil followed by stereotactic body radiotherapy: A case report.

Treatment strategies for distant organ metastasis have changed markedly since the concept of oligometastasis was introduced. The perception that distant organ metastasis is a systemic disease and not eligible for local therapy is now a thing of the past. Therefore, the present report details a case of postoperative solitary liver metastasis from esophageal squamous cell carcinoma (ESCC), which achieved a clinical complete response to chemotherapy with cisplatin and 5-fluorouracil (5-FU) followed by stereotactic body radiotherapy (SBRT). A 76-year-old male patient underwent esophagectomy for lower thoracic ESCC. At 7 months after surgery, abdominal CT revealed a solitary hypovascular mass, 28 mm in size, in segment 7 of the liver. After three courses of chemotherapy with cisplatin and 5-FU, abdominal CT revealed that the liver mass had shrunk to 7 mm in size. SBRT was then administered with a 6 MV X-ray beam generated by a linear accelerator. A total dose of 50 Gy was given in 5 fractions of 10 Gy to the liver mass. At 1 month after SBRT, abdominal CT revealed that the liver mass had disappeared. The patient received no further adjuvant chemotherapy and had no recurrence at 18 months after diagnosis of liver metastasis and 13 months after SBRT.

Successful management of gastric remnant necrosis after proximal gastrectomy using a double elementary diet tube: a case report.

BACKGROUND: The stomach has many incoming vessels and is resistant to ischemia due to the rich microvascular network within its submucosal layer. Although reports of gastric remnant necrosis after gastrectomy have been rare, mortality rates remain substantially high when present. A double elementary diet (W-ED) tube, which can be used for both enteral feeding and gastrointestinal tract decompression, has been developed for anastomotic leakage and postoperative nutritional management after upper gastrointestinal surgery. The current report presents a case of gastric remnant necrosis after proximal gastrectomy that was successfully managed through conservative treatment with a W-ED tube. CASE PRESENTATION: A 73-year-old male was referred to our hospital for an additional resection after endoscopic submucosal dissection (ESD) for gastric cancer. Endoscopic findings showed an ESD scar on the posterior wall of the upper portion of the stomach, while computed tomography (CT) showed no obvious regional lymph node enlargement and distant metastases. The patient subsequently underwent laparoscopic proximal gastrectomy and esophagogastrostomy but developed candidemia on postoperative day 7. On postoperative day 14, endoscopy revealed gastric ischemic changes around the anastomotic site, suggesting that the patient's candidemia developed due to gastric necrosis. His vital signs remained normal, while the gastric remnant ischemia was localized. Given that surgery in the presence of candidemia was considered extremely risky, conservative treatment was elected. A W-ED tube was placed nasally, after which enteral feeding was initiated along with gastrointestinal tract decompression. Although the patient subsequently developed anastomotic leakage due to gastric remnant necrosis, local control was achieved and conservative treatment was continued. On postoperative day 52, healing of the gastric remnant necrosis and anastomotic leakage was confirmed, after which the patient started drinking water. Although balloon dilation was required due to anastomotic stenosis, the patient was able to resume oral intake and was discharged on postoperative day 88. CONCLUSIONS: Herein, we present our experience with a case of gastric remnant necrosis after proximal gastrectomy, wherein conservative management was achieved using a W-ED tube. In cases involving high operative risk, the management should be mindful of gastric remnant necrosis as a post-gastrectomy complication.

Successful resection of a neuroendocrine tumor in the gallbladder: a case report.

BACKGROUND: Gallbladder neuroendocrine tumors (GB-NETs) are extremely rare, representing only 0.5% of all NETs because no neuroectodermal cells are present in the gallbladder. In 2019, the World Health Organization updated the classification of NETs based on their molecular differences. The mutation status of DAXX and ATRX has been added to the criteria for well-differentiated NETs. CASE PRESENTATION: A 50-year-old man presented to our hospital for further examination of a gallbladder polyp. He had no right quadrant pain, fever, jaundice, weight loss, or carcinoid syndrome-related symptoms. The patient hoped to avoid cholecystectomy. During the 3-year observation period, the polyp gradually increased in size from 8.3 to 9.9 mm. He decided to undergo surgery, and whole cholecystectomy was successfully performed. Immunohistochemical staining revealed positivity for chromogranin A, synaptophysin, and CD56. The Ki-67 index was < 3%. Taken together, these results led to a diagnosis of a grade 1 GB-NET. We also performed immunohistochemical staining of DAXX and ATRX, which revealed that DAXX protein expression was negative. The patient's postoperative course was uneventful, and he developed no recurrence for 8 years after surgery. CONCLUSION: We experienced a very rare case of GB-NET. Obtaining a correct preoperative diagnosis is quite difficult at the first evaluation. A GB-NET should be considered as a differential diagnosis of gallbladder tumors.

Occult follicular lymphoma in a swollen regional lymph node of gastric schwannoma.

BACKGROUND: Regional lymphadenopathy is more commonly noted in gastric schwannomas than in other gastric submucosal tumors. Most of the swollen lymph nodes associated with gastric schwannomas are non-metastatic lymphadenopathy. CASE PRESENTATION: A 69-year-old Japanese woman was referred to our hospital with a chief complaint of abdominal discomfort. Contrast-enhanced computed tomography (CT) of the abdomen revealed an extraluminal tumor with heterogeneous enhancement at the middle stomach on the lesser curve, accompanied with one swollen lymph node approximately 10 mm in size and several small lymph nodes in the perigastric region. These lymph nodes were flat; therefore, we considered them to be non-metastatic. The main tumor was removed via wedge resection. Soft and slightly swollen lymph nodes, which were compatible with the lymph nodes noted in the preoperative CT, were found near the main tumor in the fatty tissue at the lesser curvature of the stomach. An excisional biopsy of the largest lymph node was performed for the diagnosis. Based on pathological findings, a diagnosis of gastric schwannoma and follicular lymphoma (FL) was confirmed. The patient is doing well without recurrence of either the gastric schwannoma or FL 28 months postsurgery. CONCLUSIONS: The present report detailed an extremely rare case of FL coincidentally discovered in the swollen regional lymph node of gastric schwannoma.

[Right Hemicolectomy and Pancreatoduodenectomy for Transverse Colon Cancer Invasion to the Duodenum-A Case Report].

A 74-year-old woman visited her local doctor with stomach ache and weight loss. Abdominal ultrasonography showed a mass in the hepatic flexure of the transverse colon. She was referred to our hospital. Colonoscopy revealed transverse colon cancer in the hepatic flexure. Upper endoscopy showed redness of the mucosa and stenosis in the descending portion of the duodenum. Therefore, duodenal invasion was suspected. The CT scan showed a regional lymph node metastasis, but there were no obvious signs of distant metastases. From the aforementioned findings, we diagnosed the patient with duodenal invasion of transverse colon cancer(cT4b, N1, M0, cStage Ⅲ). There was no intraoperative peritoneal dissemination or liver metastasis, and we performed right hemicolectomy and pancreatoduodenectomy for transverse colon cancer. On histopathological examination, we diagnosed pT4b(Duo, Pan), N1b(3/35), M0, pStage Ⅲb. The patient had delayed gastric emptying after surgery. She recovered conservatively and was discharged on POD 37. She underwent adjuvant chemotherapy( capecitabine therapy)and has been alive without recurrence 8 months after surgery. In some cases of colon cancer invasion of other organs, long-term survival can be achieved if R0 resection is possible, and we should consider extended resection.

[A Resected Case of Angiomyolipoma Difficult to Be Distinguished from Hepatocellular Carcinoma].

A 42-year-old man complaining of left back pain was admitted to our hospital. The hepatis B and C surface antigens were negative. The serum levels of tumor markers were within the reference ranges. Abdominal ultrasound revealed an 8 cm-sized, primarily round and hyperechoic mass in the left lateral segment. Contrast-echo showed non-uniform enhancement in the arterial phase and uniform enhancement in the portal phase. This mass did not indicate"wash-out"on contrast- enhanced CT. It showed hypointensity in the hepatobiliary phase on MRI. The definitive diagnosis could not be obtained, and the patient was suspected with malignancy, such as hepatocellular carcinoma(HCC). Therefore, left hemi-hepatectomy was performed for the diagnostic treatment. Based on the immunochemical staining results, he was diagnosed with angiomyolipoma( AML). AML is composed of fat, blood vessels, and smooth muscles. It is regarded as a tumor of perivascular epithelioid cell tumor(PEComa). Early venous return and adipose tissues in the tumor were the distinctive features of this tumor. The preoperative diagnosis of AML without any fatty component as in this case is very difficult.

[A Case of Resected Peritoneal Metastasis from Hepatocellular Carcinoma after Surgery].

A 69-year-old woman with a hepatocellular carcinoma(HCC)was followed-up for type B chronic hepatitis and underwent partial hepatectomy(S6)at our hospital. Afterwards, she underwent radiofrequency ablation(RFA)therapy twice because of intrahepatic recurrence. Seven months after the first hepatectomy, a left adrenalectomy was performed for a left adrenal metastasis. Seventeen months after the first hepatectomy, a splenectomy was performed for a splenic metastasis. Forty-three months after the first hepatectomy, a second hepatectomy was performed for intrahepatic recurrence, and a right adrenalectomy was performed for an adrenal metastasis. Sixty-eight months after the first hepatectomy, an abdominal CT revealed a growing solitary lesion in the ascending colon, which was diagnosed as a peritoneal metastasis. The peritoneal dissemination was removed because there were no other extrahepatic or intrahepatic recurrences. Histologically, the resected specimen was diagnosed as a peritoneal metastasis from a HCC. The patient survived, and there were no recurrences for 6 months after the operation. We report this case of a peritoneal metastasis from a HCC after surgery with a review of the literature.

[AFP and PIVKA-â ¡ Producing Gastric Cancer with Metachronous Liver Metastasis after Gastrectomy-A Case Report].

A 67-year-old man visited his doctor because of anorexia and was diagnosed with gastric cancer based on endoscopic findings. Endoscopy revealed a 0-Ⅰ type tumor, 6 cm in size, at the gastric angle. Preoperative CT showed no apparent lymph node or distant metastases. Distal gastrectomy was performed for gastric cancer with Billroth Ⅰ reconstruction. He had no complications and was discharged on postoperative day 11. The pathological Stage was pT2N0M0, pStage ⅠB, and he underwent no adjuvant chemotherapy. Four months postoperatively, serum CA19-9, AFP, and PIVKA-Ⅱ were elevated, and CT revealed multiple liver tumors. A liver biopsy was performed for the definitive diagnosis. The patient was diagnosed with liver metastases from gastric cancer. It is considered that AFP and PIVKA-Ⅱ were produced by the liver metastasis from gastric cancer. He received chemotherapy for liver metastasis and died 1 year after the recurrence.

Effects of seasonal temperature changes on DkMyb4 expression involved in proanthocyanidin regulation in two genotypes of persimmon (Diospyros kaki Thunb.) fruit.

Persimmon fruits accumulate a large amount of proanthocyanidin (PA). Fruits of the mutant non-astringent (NA) type lose their ability to accumulate PA at an early stage of fruit development, whereas fruits of the normal astringent (A) type sustain PA accumulation until ripening. This allelotype is determined by the genotype of a single ASTRINGENCY (AST) locus. It is possible that the reduction in PA accumulation in NA-type fruits is due to phenological down-regulation of DkMyb4 (a PA regulator) and the resultant down-regulation of structural genes in the PA pathway. In this study, attempts were made to identify the regulatory mechanisms of phenological PA accumulation in A- and NA-type fruits, focusing particularly on the effects of ambient temperature. Continuous cool temperature conditions caused sustained expression of DkMyb4 in NA-type fruits, as well as in A-type fruits, resulting in increased expression of PA pathway genes and PA accumulation. However, the expression of some A/NA phenotypic marker genes was not significantly affected by the cool temperature conditions. In addition, PA composition in NA-type fruits exposed to cool temperatures differed from that in A-type fruits. These results indicate that a cool ambient temperature may have induced DkMyb4 expression and resultant PA accumulation, but did not directly affect the expression of the AST gene.

DkMyb4 is a Myb transcription factor involved in proanthocyanidin biosynthesis in persimmon fruit.

Proanthocyanidins (PAs) are secondary metabolites that contribute to the protection of the plant and also to the taste of the fruit, mainly through astringency. Persimmon (Diospyros kaki) is unique in being able to accumulate abundant PAs in the fruit flesh. Fruits of the nonastringent (NA)-type mutants lose their ability to produce PA at an early stage of fruit development, while those of the normal astringent (A) type remain rich in PA until fully ripened. The expression of many PA pathway genes was coincidentally terminated in the NA type at an early stage of fruit development. The five genes encoding the Myb transcription factor were isolated from an A-type cultivar (Kuramitsu). One of them, DkMyb4, showed an expression pattern synchronous to that of the PA pathway genes in A- and NA-type fruit flesh. The ectopic expression of DkMyb4 in kiwifruit (Actinidia deliciosa) induced PA biosynthesis but not anthocyanin biosynthesis. The suppression of DkMyb4 in persimmon calluses caused a substantial down-regulation of the PA pathway genes and PA biosynthesis. Furthermore, analysis of the DNA-binding ability of DkMyb4 showed that it directly binds to the MYBCORE cis-motif in the promoters of the some PA pathway genes. All our results indicate that DkMyb4 acts as a regulator of PA biosynthesis in persimmon and, therefore, suggest that the reduction in the DkMyb4 expression causes the NA-type-specific down-regulation of PA biosynthesis and resultant NA trait.