Hajime Kanauchi

Telomerase activity and telomere length in benign and malignant human thyroid tissues

Several studies have demonstrated that telomerase is activated and telomere length is altered in various types of tumors. In this study, we investigated telomerase activities and telomere length in 21 thyroid tumors. Telomerase activity was detected in 11 of 12 thyroid cancers and three of nine follicular adenomas. The mean telomere lengths in the cancers tissue and follicular adenomas were lower than in the respective background tissues, the differences being significant (P=0.0055 and P<0.006), respectively. Our findings suggest that change in telomerase activity and telomere length may be important for development of thyroid tumors.

ErbB receptor tyrosine kinase/NF-κB signaling controls mammosphere formation in human breast cancer.

Breast cancer is one of the most common cancers in humans. However, our understanding of the cellular and molecular mechanisms underlying tumorigenesis in breast tissues is limited. Here, we identified a molecular mechanism that controls the ability of breast cancer cells to form multicellular spheroids (mammospheres). We found that heregulin (HRG), a ligand for ErbB3, induced mammosphere formation of a breast cancer stem cell (BCSC)–enriched population as well as in breast cancer cell lines. HRG-induced mammosphere formation was reduced by treatment with inhibitors for phosphatidyl inositol 3-kinase (PI3K) or NF-κB and by expression of IκBα-Super Repressor (IκBαSR), a dominant-negative inhibitor for NF-κB. Moreover, the overexpression of IκBαSR in breast cancer cells inhibited tumorigenesis in NOD/SCID mice. Furthermore, we found that the expression of IL8, a regulator of self-renewal in BCSC-enriched populations, was induced by HRG through the activation of the PI3K/NF-κB pathway. These findings illustrate that HRG/ErbB3 signaling appears to maintain mammosphere formation through a PI3K/NF-κB pathway in human breast cancer.

Ischaemic preconditioning ameliorates functional disturbance and impaired renal perfusion in rat ischaemia-reperfused kidneys.

1. The effects of ischaemic preconditioning (IP) on renal function, haemodynamics and lipid peroxidation in the rat ischaemia–reperfused kidney model were examined.

Consistent Decrease in Telomere Length in Parathyroid Tumors but Alteration in Telomerase Activity Limited to Malignancies: Preliminary Report

AbstractTelomerase is known to be activated and telomere length altered in various types of malignant and benign tumors, but whether this is also the case for parathyroid lesions has hitherto been unclear. We therefore investigated telomerase activity and telomere length in 3 parathyroid metastatic cancers, 6 adenomas, 2 cases of parathyroid hyperplasia, and 16 samples of normal parathyroid tissue. Telomerase activity, assayed by the telomeric repeat amplification protocol, was detected in all of the parathyroid cancers (100%), in none of the 8 parathyroid benign lesions, and in only 1 of the 16 normal parathyroid samples (8.3%). Telomere length, determined by the terminal restriction fragment assay, was reduced in the tumor tissues with a mean telomere length of 8.23 ± 0.86 kbp compared with the 12.61 ± 0.81 kbp for the 16 age-matched subjects (p = 0.002). The results indicate that telomerase activity and telomere length may reflect the biologic behavior of individual parathyroid lesions.

Effect of glutamine on acute lung injury in rats with endotoxemia

We administered endotoxin to rats to produce an acute lung injury model, and assessed the effect on respiratory function when glutamine was added to the solution for total parenteral nutrition. Rats given total parenteral nutrition with glutamine as 33% of the amino acid content were compared with rats given no glutamine. Endotoxin (500 microg/kg) was administered intravenously after 72 h of total parenteral nutrition. The survival rate and the nitrogen balance were significantly improved (P < 0.05) at 48 h after endotoxin administration as a result of glutamine treatment. In addition, the arterial oxygen partial pressure was significantly increased (P < 0.01) and the wet: dry lung weight ratio was decreased (P < 0.05) by glutamine. These results suggested that glutamine improved endotoxin-induced acute lung injury in rats.

Addiction to the IGF2-ID1-IGF2 circuit for maintenance of the breast cancer stem-like cells.

The transcription factor nuclear factor-κB (NF-κB) has important roles for tumorigenesis, but how it regulates cancer stem cells (CSCs) remains largely unclear. We identified insulin-like growth factor 2 (IGF2) is a key target of NF-κB activated by HER2/HER3 signaling to form tumor spheres in breast cancer cells. The IGF2 receptor, IGF1 R, was expressed at high levels in CSC-enriched populations in primary breast cancer cells. Moreover, IGF2-PI3K (IGF2-phosphatidyl inositol 3 kinase) signaling induced expression of a stemness transcription factor, inhibitor of DNA-binding 1 (ID1), and IGF2 itself. ID1 knockdown greatly reduced IGF2 expression, and tumor sphere formation. Finally, treatment with anti-IGF1/2 antibodies blocked tumorigenesis derived from the IGF1Rhigh CSC-enriched population in a patient-derived xenograft model. Thus, NF-κB may trigger IGF2-ID1-IGF2-positive feedback circuits that allow cancer stem-like cells to appear. Then, they may become addicted to the circuits. As the circuits are the Achilles’ heels of CSCs, it will be critical to break them for eradication of CSCs.

Review of 41 patients operated on for primary hyperparathyroidism

We reviewed 41 cases of operation for primary hyperparathyroidism (PHPT) in our institution between 1987 and 1999. The objective of this study was 1) to evaluate the sensitivity and positive predictive value of several localization studies for an enlarged parathyroid gland; 2) to determine whether a selective. unilateral-exploration operation is safe; and 3) to investigate rates of coexisting malignancies of other organs. A total of 61 enlarged parathyroid glands (701 +/- 131 mg wt) were removed, and the lesions consisted of 32 adenomas, two cancers, and seven hyperplasias. MIBI scintigraphy had both a high sensitivity (88.9%) and positive predictive value (88.9%) for localization of abnormal parathyroid glands and yielded better performance than the other techniques, including ultrasonography, CT scanning, and Tl-Tc scintigraphy. However, all of the localization techniques failed to detect enlarged glands (18/32 glands = 62.5%) in patients with multi-glandular parathyroid lesions. Initial operations with selective unilateral exploration of the neck were successful in 23 of 24 patients (95.8%). Operative failure was due to missing the second adenoma of a double adenoma. Malignant tumors were found in 11 patients (26.8%) previously treated or concurrently managed at the time of parathyroidectomy. There was a significant increase in serum-intact PTH level in patients with concurrent malignant tumors compared to patients who had no association of malignancies. In conclusion, 1) at least two preoperative localization tests, an MIBI scan and ultrasonography, are helpful in accurately localizing an abnormal parathyroid gland; 2) selective unilateral exploration is safe and desirable if the second ipsilateral gland is normal macroscopically; and 3) systematic examination for malignant tumors is necessary in PHPT patients before and after parathyroidectomy.

Catecholamine and cytokine response to laparoscopic adrenalectomy in patients with pheochromocytoma

This study assesses the surgical stress of laparoscopic adrenalectomy (LA) in patients with pheochromocytoma using catecholamine and cytokine. The study was conducted on one patient who had laparoscopic adrenalectomy performed for pheochromocytoma, and three patients as controls who had undergone laparoscopic cholecystectomy (LC) for cholecystolithiasis. Catecholamines, tumor necrosis factor alpha (TNFalpha) and interleukin 6 (IL-6) were measured at 30-minute intervals intraoperatively, and on the first, third and fifth postoperative days (POD) respectively. Plasma TNFalpha and IL-6 were measured by a commercially available sandwich enzyme-linked immunosorbent assay test. During the operation. changes of catecholamine concentration in LA were far larger than those in LC. The changes of TNFalpha concentration in LA were also larger than those in LC. TNFalpha returned to basal value at the end of the operation in LC, but it did not in LA. TNFalpha concentration in LC changed a little after the surgery, whereas that in LA sharply increased and was maintained at a high level from 1 POD until 5 POD. Enhanced cytokine responses were observed in LA compared to LC during and after the surgery. We concluded that laparoscopic adrenalectomy may give those patients with pheochromocytoma more surgical stress than laparoscopic cholecystectomy for cholecystolithiasis, during and after the operation.

An autocrine/paracrine circuit of growth differentiation factor (GDF) 15 has a role for maintenance of breast cancer stem-like cells

Cancer stem cells are thought to be responsible for tumor growth, recurrence, and resistance to conventional cancer therapy. However, it is still unclear how they are maintained in tumor tissues. Here, we show that the growth differentiation factor 15 (GDF15), a member of the TGFβ family, may maintain cancer stem-like cells in breast cancer tissues by inducing its own expression in an autocrine/paracrine manner. We found that GDF15, but not TGFβ, increased tumor sphere formation in several breast cancer cell lines and patient-derived primary breast cancer cells. As expected, TGFβ strongly stimulated the phosphorylation of Smad2. GDF15 also stimulated the phosphorylation of Smad2, but the GDF15-induced tumor sphere forming efficiency was not significantly affected by treatment with SB431542, an inhibitor of the TGFβ signaling. Although TGFβ transiently activated ERK1/2, GDF15 induced prolonged activation of ERK1/2. Treatment with U0126, an inhibitor of the MEK-ERK1/2 signaling, greatly inhibited the GDF15-induced tumor sphere formation. Moreover, cytokine array experiments revealed that GDF15, but not TGFβ, is able to induce its own expression; furthermore, it appears to form an autocrine/paracrine circuit to continuously produce GDF15. In addition, we found heterogeneous expression levels of GDF15 among cancer cells and in human breast cancer tissues using immunohistochemistry. This may reflect a heterogeneous cancer cell population, including cancer stem-like cells and other cancer cells. Our findings suggest that GDF15 induces tumor sphere formation through GDF15-ERK1/2-GDF15 circuits, leading to maintenance of GDF15high cancer stem-like cells. Targeting GDF15 to break these circuits should contribute to the eradication of tumors.

Diffuse large B-cell lymphoma in the thyroid gland associated with primary hyperparathyroidism

We report a case of primary hyperparathyroidism associated with a malignant lymphoma in the thyroid gland. A 68-year-old woman was admitted to hospital with a cervical mass. Ultrasound and computed tomography (CT) revealed a hypoechoic, multinodular tumor in the left thyroid gland. A gallium-67 citrate scintigram revealed intense radioisotope uptake in the thyroid tumor. Histological examination of biopsy specimens indicated that this tumor was a large B-cell lymphoma. The coexistence of parathyroid adenoma in this patient was revealed by a sestamibi scintigram, performed prior to chemotherapy. Following the complete remission of the lymphoma by chemotherapy, we carried out an excision of the single parathyroid adenoma. To our knowledge, this is the first report to describe a malignant thyroid lymphoma associated with primary hyperparathyroidism.