Roles of lysophosphatidic acid (LPA) receptor-mediated signaling in cancer cell biology.

Lysophosphatidic acid (LPA) is a simple lipid which is endogenously synthesized from lysophosphatidylcholine (LPC) by autotaxin (ATX). LPA mediates a variety of cellular responses through the binding of G protein-coupled LPA receptors (LPA1 to LPA6). It is considered that LPA receptor-mediated signaling plays an important role in the pathogenesis of human malignancy. Genetic alterations and epigenetic changes of LPA receptors have been detected in some cancer cells as well as LPA per se. Moreover, LPA receptors contribute to the promotion of tumor progression, including cell proliferation, invasion, metastasis, tumorigenicity, and angiogenesis. In recent studies, the activation of LPA receptor-mediated signaling regulates chemoresistance and radiosensitivity in cancer cells. This review provides an updated overview on the roles of LPA receptor-mediated signaling in the regulation of cancer cell functions and its potential utility as a molecular target for novel therapies in clinical cancer approaches.

Reoperation after surgery for bone metastasis of renal cell carcinoma.

BACKGROUND AND OBJECTIVE: The prognosis of metastatic renal cell carcinoma (RCC) has markedly improved with the advent of molecular targeted therapies and immune checkpoint inhibitors. However, the therapeutic response in patients with bone metastasis remains low; therefore, surgery still plays a significant role in treatment of bone metastasis. It is important to maintain quality of life for patients with bone metastasis from RCC and avoid reoperation after surgery for bone metastasis. Therefore, we investigated the risk factors for reoperation after surgery in patients with bone metastasis from RCC. METHODS: We retrospectively studied 103 bones of 97 patients who underwent surgery for bone metastasis of RCC from 2001 to 2023 at our institutions. RESULTS: Reoperation was performed in 10 (9.7%) of 103 bones. There was no correlation between reoperation-free survival and any of the following variables: preoperative and postoperative radiotherapy, site of bone metastasis, indication for surgery (solitary bone metastasis or impending or pathologic fractures), surgical method (intramedullary nailing fixation, curettage, or en bloc resection), preoperative embolization, or survival. CONCLUSION: The risk of reoperation for bone metastasis of RCC does not appear to be based on the surgical method.

Is perioperative chemotherapy effective in patients with localized myxoid liposarcoma?

BACKGROUND: This study aimed to compare the local recurrence, distant metastasis and disease-specific survival rates of patients with localized myxoid liposarcoma in the surgery and adjuvant chemotherapy group versus the surgery alone group. METHODS: A total of 456 patients in the Japanese National Bone and Soft Tissue Tumour Registry database who had localized myxoid liposarcoma and underwent surgery and adjuvant chemotherapy or surgery alone between 2001 and 2019 were included in this retrospective study. The study adjusted for background differences between patients who underwent surgery and adjuvant chemotherapy (n = 228) or surgery alone (n = 228) using propensity score matching. RESULTS: Univariate analysis showed no significant difference in local recurrence rate between the two groups (5-year local recurrence-free survival: 98.6% [95% confidence interval: 95.9-99.6] vs. 94.0% [95% confidence interval: 89.7-96.6], P = 0.052). Univariate analysis showed no difference in the incidence of distant metastases between the two groups (5-year distant metastasis-free survival: 80.5% [95% confidence interval: 73.9-85.8] vs. 75.1% [95% confidence interval: 67.7-81.2], P = 0.508). Univariate analysis showed no difference in disease-specific survival between the two groups (5-year disease-specific survival: 92.6% [95% confidence interval: 86.1-96.2] vs. 93.2% [95% confidence interval: 87.6-96.4], P = 0.804). In the high-risk group (n = 203) with high-grade tumours and tumour size ≥10 cm, there were no significant differences in the local recurrence, distant metastasis and disease-specific survival rates between the surgery and adjuvant chemotherapy group and the surgery alone group. CONCLUSION: The effect of adjuvant chemotherapy on localized myxoid liposarcoma appears to be limited.

En bloc resection and reconstruction using a talar prosthesis for malignant talar bone tumor: a surgical technique.

En bloc resection is required for treatment of intermediate-grade talar tumors with extraosseous extension (Enneking stage 3) and malignant talar tumors without intra-articular invasion (Enneking stages IA and IIA). After resection, reconstruction options include tibiocalcaneal fusion, frozen autograft, and talar prosthesis; however, a talar prosthesis is preferable because it preserves ankle range of motion, does not cause leg length discrepancy, and is associated with good long-term outcomes. To the best of our knowledge, en bloc resection and reconstruction of a malignant talar tumor has not been previously reported in detail. We report a detailed surgical technique for en bloc resection of a malignant talar bone tumor using combined anterior and lateral approaches followed by reconstruction using a talar prosthesis.

Response rate specific to bone metastasis of various cancers for immune checkpoint inhibitors: a systematic review.

PURPOSE: Immune checkpoint inhibitors (ICIs) have improved the prognosis of patients with cancer, such as melanoma, renal cell carcinoma, head and neck cancer, non-small cell lung cancer (NSCLC), and urothelial carcinoma. The extension of life expectancy has led to an increased incidence of bone metastases (BM) among patients with cancer. BM result in skeletal-related events, including severe pain, pathological fractures, and nerve palsy. Surgery is typically required for the treatment of BM in patients with an impending fracture; however, it may be avoided in those who respond to ICIs. We systematically reviewed studies analyzing BM responses to treatment with ICIs. METHODS: This study was conducted in accordance with the recommendations of the Preferred Reporting Items for Systematic Reviews and Meta-analyses 2020 statement and registered in the UMIN Clinical Trials Registry (ID: UMIN000053707). Studies reporting response rates based on the Response Evaluation Criteria in Solid Tumors (RECIST) or the MD Anderson Cancer Center (MDA) criteria specific for BM in patients treated with ICIs were included; reports of fewer than five cases and review articles were excluded. Studies involving humans, published in English and Japanese, were searched. The PubMed, Embase, and the Cochrane Central Register of Controlled Trials (CENTRAL) databases were searched. Ultimately, nine studies were analyzed. The Risk of Bias Assessment tool for Non-randomized Studies was used to assess the quality of studies. RESULTS: Based on the MDA criteria, complete response (CR) or partial response (PR) was observed in 44-78% and 62% patients treated with ICIs plus denosumab for NSCLC and melanoma, respectively. According to the RECIST, CR or PR was recorded in 5% and 7-28% of patients treated with ICIs for renal cell carcinoma and urothelial carcinoma, respectively. CONCLUSION: Although response rates to ICIs for BM are poor, patients treated with ICI plus denosumab for bone metastases with impending fractures from NSCLC and melanoma are likely to avoid surgery to prevent fractures.

Giant cell tumor of bone with secondary aneurysmal bone cyst does not have a higher risk of local recurrence.

BACKGROUND: Fluid-fluid levels (FFLs) is found in 10%-16% of giant cell tumor of bone (GCTB), and the presence of FFLs raises the suspicion of GCTB with secondary aneurysmal bone cyst (ABC), which can lead to increased intraoperative bleeding and, blurring the operative field, be associated with a risk of local recurrence. The first objective of this study is to determine whether secondary ABC is associated with a higher risk of local recurrence after curettage in patients with GCTB of the extremities. The second objective of this study is to investigate the sensitivity, specificity, positive predictive value, and negative predictive value of the presence of FFLs detected on magnetic resonance imaging (MRI) to diagnose secondary ABC associated with GCTB. METHODS: Two hundred and eighty patients with GCTB of the extremities who underwent curettage at the authors' institutions between 1980 and 2021 were included in this study. RESULTS: Secondary ABC was found in 36 of 280 patients (12.9%) and local recurrence occurred in 66 of 280 patients (23.6%). Multivariate analysis showed no significant correlation between secondary ABC and local recurrence (hazard ratio [HR]: 1.87 (95% confidence interval [CI]: 1.00-3.53]; p = 0.051). Preoperative MRI revealed FFLs in 13 of 82 patients (15.9%). Sensitivity, specificity, positive predictive value, and negative predictive value of FFLs detected on preoperative MRI to diagnose secondary ABC were 36.8%, 90.5%, 53.8%, and 82.6%, respectively. CONCLUSION: The results of this study showed that secondary ABC does not increase the risk of local recurrence after curettage in patients with GCTB of the extremities. Although rare, FFLs were present in patients with GCTB and half of those with FFLs detected on preoperative MRI had secondary ABC.

Comparison of pre-operative and post-operative radiotherapy in patients with localized myxoid liposarcoma.

BACKGROUND: Myxoid liposarcoma is more radiosensitive than other soft tissue sarcomas, and radiotherapy has been reported to reduce tumour size. This study was performed to compare the rates of local recurrence, survival and wound complications between pre- and post-operative radiotherapy for localized myxoid liposarcoma. METHODS: From the Japanese Nationwide Bone and Soft Tissue Tumor Registry database, 200 patients with localized myxoid liposarcoma who received pre- (range, 30-56 Gy) or post-operative (range, 45-70 Gy) radiotherapy and surgery were included in this retrospective study. Propensity score matching was used to adjust for background differences between patients who received pre- and post-operative radiotherapy. RESULTS: Local recurrence occurred in five (5.0%) and nine (9.0%) patients in the pre- and post-operative radiotherapy groups, respectively (both n = 100). The median follow-up time from diagnosis was 40.5 months (IQR, 26.3-74). Univariate analysis showed a similar risk of local recurrence between the pre- and post-operative radiotherapy groups (5-year local recurrence-free survival 94.9% [95% CI 87.0-98.1] vs. 89.0% [95% CI 79.6-94.3]; P = 0.167). Disease-specific survival was similar between the pre- and post-operative radiotherapy groups (5-year disease-specific survival 88.1% [95% CI 75.5-94.6] vs. 88.4% [95% CI 77.3-94.5]; P = 0.900). The incidence of wound complications was similar between the pre- and post-operative radiotherapy groups (7.0% vs. 12.0%; P = 0.228). CONCLUSIONS: There was no difference in local recurrence, survival or incidence of wound complications between pre- and post-operative radiotherapy for localized myxoid liposarcoma. Therefore, pre-operative radiotherapy for myxoid liposarcoma provides clinical results equivalent to post-operative radiotherapy.

Outcome of re-operation for local recurrence following pre-operative denosumab administration and curettage for giant cell tumour of bone with difficult joint preservation.

PURPOSE: Denosumab enables joint-sparing surgery (curettage) and surgical downstaging in patients with giant cell tumour of bone (GCTB), where joint preservation is not possible. However, denosumab treatment causes osteosclerosis of the lesion, making it difficult to curet the lesion, leaving the tumour behind, and increasing the local recurrence rate. We performed a three-centre retrospective study to investigate the postoperative local re-recurrence rate, joint preservation status, and functional outcomes of locally recurrent lesions after preoperative denosumab treatment and curettage in patients with difficult joint preservation. METHODS: We included 38 of 142 patients with primary GCTB of the extremities who underwent preoperative denosumab and curettage between 2009 and 2021 with local recurrence. Preoperative denosumab was indicated in patients with minimal residual periarticular and subchondral bones, large extraosseous lesions (Campanacci stage 3), and pathological fractures that made joint preservation difficult. RESULTS: Local re-recurrence occurred in 6 (15.8%) of the 38 patients. In 29 patients who underwent re-curettage, local re-recurrence occurred in six patients (20.7%); however, in nine patients who underwent en bloc resection, no local re-recurrence was observed. The joint preservation rate was 63.2% (24 of 38 patients), with a median Musculoskeletal Tumor Society score of 28 (interquartile range: 26.8-29.0). The median follow-up period after surgery for local recurrence was 63.5 months (interquartile range: 42.5-82.4). CONCLUSION: Since the local re-recurrence rate after re-curettage for local recurrence was low, and the joint preservation rate and affected limb function were good, preoperative denosumab administration may be considered in patients who require downstaging to maintain good limb function (joint preservation).

5-Aminolevrinic Acid Exhibits Dual Effects on Stemness in Human Sarcoma Cell Lines under Dark Conditions.

5-aminolevulinic acid (ALA) is used for tumor-targeting phototherapy because it is converted to protoporphyrin IX (PPIX) upon excitation and induces phototoxicity. However, the effect of ALA on malignant cells under unexcited conditions is unclear. This information is essential when administering ALA systemically. We used sarcoma cell lines that usually arise deep in the body and are rarely exposed to light to examine the effects of ALA treatment under light (daylight lamp irradiation) and dark (dark room) conditions. ALA-treated human SW872 liposarcoma cells and human MG63 osteosarcoma cells cultured under light exhibited growth suppression and increased oxidative stress, while cells cultured in the dark showed no change. However, sphere-forming ability increased in the dark, and the expression of stem-cell-related genes was induced in dark, but not light, conditions. ALA administration increased heme oxygenase 1 (HO-1) expression in both cell types; when carbon monoxide (CO), a metabolite of HO-1, was administered to sarcoma cells via carbon-monoxide-releasing molecule 2 (CORM2), it enhanced sphere-forming ability. We also compared the concentration of biliverdin (BVD) (a co-product of HO-1 activity alongside CO) with sphere-forming ability when HO-1 activity was inhibited using ZnPPIX in the dark. Both cell types showed a peak in sphere-forming ability at 60-80 µM BVD. Furthermore, a cell death inhibitor assay revealed that the HO-1-induced suppression of sphere formation was rescued by apoptosis or ferroptosis inhibitors. These findings suggest that in the absence of excitation, ALA promotes HO-1 expression and enhances the stemness of sarcoma cells, although excessive HO-1 upregulation induces apoptosis and ferroptosis. Our data indicate that systemic ALA administration induces both enhanced stemness and cell death in malignant cells located in dark environments deep in the body and highlight the need to pay attention to drug delivery and ALA concentrations during phototherapy.

Oxidized high mobility group B-1 enhances metastability of colorectal cancer via modification of mesenchymal stem/stromal cells.

High mobility group box-1 (HMGB1) is known to be a chemotactic factor for mesenchymal stem/stromal cells (MSCs), but the effect of post-translational modification on its function is not clear. In this study, we hypothesized that differences in the oxidation state of HMGB1 would lead to differences in the function of MSCs in cancer. In human colorectal cancer, MSCs infiltrating into the stroma were correlated with liver metastasis and serum HMGB1. In animal models, oxidized HMGB1 mobilized three-fold fewer MSCs to subcutaneous tumors compared with reduced HMGB1. Reduced HMGB1 inhibited the proliferation of mouse bone marrow MSCs (BM-MSCs) and induced differentiation into osteoblasts and vascular pericytes, whereas oxidized HMGB1 promoted proliferation and increased stemness, and no differentiation was observed. When BM-MSCs pretreated with oxidized HMGB1 were co-cultured with syngeneic cancer cells, cell proliferation and stemness of cancer cells were increased, and tumorigenesis and drug resistance were promoted. In contrast, co-culture with reduced HMGB1-pretreated BM-MSCs did not enhance stemness. In an animal orthotopic transplantation colorectal cancer model, oxidized HMGB1, but not reduced HMGB1, promoted liver metastasis with intratumoral MSC chemotaxis. Therefore, oxidized HMGB1 reprograms MSCs and promotes cancer malignancy. The oxidized HMGB1-MSC axis may be an important target for cancer therapy.

Effect of adjuvant chemotherapy on periosteal osteosarcoma: a systematic review.

BACKGROUND AND OBJECTIVE: The effects of adjuvant chemotherapy on periosteal osteosarcoma are controversial. Therefore, we conducted a systematic review of studies comparing mortality, local recurrence, distant metastasis and secondary malignancy incidence among patients who underwent surgery and (neo-) adjuvant chemotherapy or surgery alone for periosteal osteosarcoma without distant metastases at diagnosis. METHODS: Of the 210 studies identified in the search, 13 were included in this study, involving 291 patients with periosteal osteosarcoma in total. RESULTS: The mortality rates in the surgery and (neo-) adjuvant chemotherapy and surgery alone groups were 11.3% (8/71) and 16.3% (16/98), respectively. The overall pooled odds ratio was 0.89 (P = 0.800). The local recurrence rate in the surgery and (neo-) adjuvant chemotherapy group was 12.1% (8/66), while that in the surgery alone group was 17.6% (13/74). The overall pooled odds ratio was 1.31 (P = 0.601). The distant metastasis rate in the surgery and (neo-) adjuvant chemotherapy group was 15.2% (10/66) and that in the surgery alone group was 10.8% (8/74). The overall pooled odds ratio was 1.51 (P = 0.444). The incidence of secondary malignancy in the surgery and (neo-) adjuvant chemotherapy group was 7.6% (9/118) and that in the surgery alone group was 2.7% (2/74). The overall pooled odds ratio was 2.29 (P = 0.187). CONCLUSIONS: Adjuvant chemotherapy did not appear to improve the prognosis of patients with periosteal osteosarcoma. No association was found between the use of adjuvant chemotherapy and development of secondary malignancies.

Risk factors of fracture following curettage for bone giant cell tumors of the extremities.

BACKGROUND: Following curettage of giant cell tumor of bone (GCTB), it is common to fill the cavity with polymethylmethacrylate (PMMA) bone cement, bone allograft, or artificial bone to maintain bone strength; however, there is a 2-14% risk of postoperative fractures. We conducted this retrospective study to clarify the risk factors for fractures after curettage for GCTB of the extremities. METHODS: This study included 284 patients with GCTBs of the extremities who underwent curettage at our institutions between 1980 and 2018 after excluding patients whose cavities were not filled with anything or who had additional plate fixation. The tumor cavity was filled with PMMA bone cement alone (n = 124), PMMA bone cement and bone allograft (n = 81), bone allograft alone (n = 63), or hydroxyapatite graft alone (n = 16). RESULTS: Fractures after curettage occurred in 10 (3.5%) patients, and the median time from the curettage to fracture was 3.5 months (interquartile range [IQR], 1.8-8.3 months). The median postoperative follow-up period was 86.5 months (IQR, 50.3-118.8 months). On univariate analysis, patients who had GCTB of the proximal or distal femur (1-year fracture-free survival, 92.5%; 95% confidence interval [CI]: 85.8-96.2) presented a higher risk for postoperative fracture than those who had GCTB at another site (100%; p = 0.0005). Patients with a pathological fracture at presentation (1-year fracture-free survival, 88.2%; 95% CI: 63.2-97.0) presented a higher risk for postoperative fracture than those without a pathological fracture at presentation (97.8%; 95% CI: 95.1-99.0; p = 0.048). Patients who received bone grafting (1-year fracture-free survival, 99.4%; 95% CI: 95.7-99.9) had a lower risk of postoperative fracture than those who did not receive bone grafting (94.4%; 95% CI: 88.7-97.3; p = 0.003). CONCLUSIONS: For GCTBs of the femur, especially those with pathological fracture at presentation, bone grafting after curettage is recommended to reduce the risk of postoperative fracture. Additional plate fixation should be considered when curettage and cement filling without bone grafting are performed in patients with GCTB of the femur. This should be specially performed for those patients with a pathological fracture at presentation.

Soft-tissue reconstruction after soft-tissue sarcoma resection: the clinical outcomes of 24 patients.

PURPOSE: Pedicle or free-flap reconstruction is important in surgical sarcoma management. Free flaps are indicated only when pedicle flaps are considered inadequate; however, they are associated with a higher risk of flap failure, longer surgical times, and technical difficulty. To determine the skin defect size that can be covered by a pedicle flap, we investigated the clinical outcomes and complications of reconstruction using pedicle flaps vs. free flaps after sarcoma resection. METHODS: We retrospectively studied the medical records of 24 patients with soft-tissue sarcomas who underwent reconstruction using a pedicle (n = 20) or free flap (n = 4) following wide tumour resection. RESULTS: All skin defects of the knee, lower leg, and ankle were reconstructed using a pedicle flap. Skin defects of the knee, lower leg, and ankle were covered by up to 525 cm2, 325 cm2, and 234 cm2, respectively. The amount of blood loss was significantly greater in the free-flap group than in the pedicle flap group (p = 0.011). Surgical time was significantly shorter in the pedicle flap group than in the free-flap group (p = 0.006). Total necrosis was observed in one (25%) patient in the free-flap group; no case of total necrosis was observed in the pedicle flap group. CONCLUSION: Less blood loss, shorter surgical time, and lower risk of total flap necrosis are notable advantages of pedicle flaps over free flaps. Most skin defects, even large ones, of the lower extremities following sarcoma resection can be covered using a single pedicle flap or multiple pedicle flaps.

Intralesional nerve-sparing surgery versus non-surgical treatment for giant cell tumor of the sacrum.

BACKGROUND: There is no standard treatment for giant cell tumors of the sacrum. We compared the outcomes and complications in patients with sacral giant cell tumors who underwent intralesional nerve-sparing surgery with or without (neo-) adjuvant therapies versus those who underwent non-surgical treatment (denosumab therapy and/or embolization). METHODS: We retrospectively investigated 15 cases of sacral giant cell tumors treated at two institutions between 2005 and 2020. Nine patients underwent intralesional nerve-sparing surgery with or without (neo-) adjuvant therapies, and six patients received non-surgical treatment. The mean follow-up period was 85 months for the surgical group (range, 25-154 months) and 59 months (range, 17-94 months) for the non-surgical group. RESULTS: The local recurrence rate was 44% in the surgical group, and the tumor progression rate was 0% in the non-surgical group. There were two surgery-related complications (infection and bladder laceration) and three denosumab-related complications (apical granuloma of the tooth, stress fracture of the sacroiliac joint, and osteonecrosis of the jaw). In the surgical group, the mean modified Biagini score (bowel, bladder, and motor function) was 0.9; in the non-surgical group, it was 0.5. None of the 11 female patients became pregnant or delivered a baby after developing a sacral giant cell tumor. CONCLUSIONS: The cure rate of intralesional nerve-sparing surgery is over 50%. Non-surgical treatment has a similar risk of complications to intralesional nerve-sparing surgery and has better functional outcomes than intralesional nerve-sparing surgery, but patients must remain on therapy over time. Based on our results, the decision on the choice of treatment for sacral giant cell tumors could be discussed between the surgeon and the patient based on the tumor size and location.

Role of Glycated High Mobility Group Box-1 in Gastric Cancer.

Advanced glycation end products (AGEs) are produced in response to a high-glucose environment and oxidative stress and exacerbate various diseases. Nε-(Carboxymethyl)lysine (CML) is an AGE that is produced by the glycation of lysine residues of proteins. There are a few reports on alterations in protein function due to CML modification; however, its association with cancer is not clear. We investigated the significance of CML modification in high mobility group box protein-1 (HMGB1), a cytokine that is significantly associated with cancer progression. Treatment of the gastric cancer cell lines TMK1 and MKN74 with glyoxal or glucose resulted in increased CML modification compared to untreated cells. CML-HMGB1 was modified via oxidation and more pronouncedly activated the receptor for AGE and downstream AKT and NF-κB compared to naïve HMGB1 and oxidized HMGB1. CML-HMGB1 bound with reduced affinity to DNA and histone H3, resulting in enhanced extranuclear translocation and extracellular secretion. Treatment of gastric cancer cells with CML-HMGB1 enhanced cell proliferation and invasion, sphere formation, and protection from thapsigargin-induced apoptosis, and decreased 5-FU sensitivity in comparison to HMGB1. Further, CML-HMGB1 was detected at various levels in all the 10 gastric cancer tumor specimens. HMGB1 levels correlated with primary tumor progression and distant metastasis, whereas CML-HMGB1 levels were associated with primary tumor progression, lymph node metastasis, distant metastasis, and stage. In addition, CML-HMGB1 levels correlated with oxidative stress in cancer tissues and resistance to neoadjuvant therapy. Therefore, CML modification of HMGB1 enhanced the cancer-promoting effect of HMGB1. In this study, CML-HMGB1 has been highlighted as a new therapeutic target, and analysis of the molecular structure of CML-HMGB1 is desired in the future.

Anti-Stem Cell Property of Pterostilbene in Gastrointestinal Cancer Cells.

Pterostilbene (PTE) is a natural sterbenoid contained in blueberries that has an antioxidant effect. In contrast, PTE also generates oxidative stress in cancer cells and provides an antitumor effect. Here, we examined the potential mechanism of this contrasting effect of PTE using three gastrointestinal cancer cell lines, namely CT26, HT29, and MKN74. PTE showed a dose-dependent inhibition of cell proliferation, sphere-forming ability, and stem cell marker expression in all three cell lines. Furthermore, the cells treated with PTE showed an increase in mitochondrial membrane potential and an increase in mitochondrial oxidative stress and lipid peroxide. Upon concurrent treatment with vitamin E, N-acetyl-L-cysteine, and PTE, the PTE-induced mitochondrial oxidative stress and growth inhibition were suppressed. These findings indicate that PTE induces oxidative stress in cancer cells, suppresses stemness, and inhibits proliferation. These antitumor effects of PTE are considered to be useful in cancer treatment.

Frequent mutations of genes encoding vacuolar H+ -ATPase components in granular cell tumors.

Granular cell tumors (GCTs) are rare mesenchymal tumors that exhibit a characteristic morphology and a finely granular cytoplasm. The genetic alterations responsible for GCT tumorigenesis had been unknown until recently, when loss-of-function mutations of ATP6AP1 and ATP6AP2 were described. Thus, we performed whole-exome sequencing, RNA sequencing, and targeted sequencing of 51 GCT samples. From these genomic analyses, we identified mutations in genes encoding vacuolar H+ -ATPase (V-ATPase) components, including ATP6AP1 and ATP6AP2, in 33 (65%) GCTs. ATP6AP1 and ATP6AP2 mutations were found in 23 (45%) and 2 (4%) samples, respectively, and all were truncating or splice site mutations. In addition, seven other genes encoding V-ATPase components were also mutated, and three mutations in ATP6V0C occurred on the same amino acid (isoleucine 136). These V-ATPase component gene mutations were mutually exclusive, with one exception. These results suggest that V-ATPase function is impaired in GCTs not only by loss-of-function mutations of ATP6AP1 and ATP6AP2 but also through mutations of other subunits. Our findings provide additional support for the hypothesis that V-ATPase dysfunction promotes GCT tumorigenesis.

Similar local recurrence but better function with curettage versus resection for bone giant cell tumor and pathological fracture at presentation.

BACKGROUND: There are conflicting reports for the outcome of the patients with giant cell tumor of bone (GCTB) and pathological fracture at presentation treated with curettage or resection. This study compared local recurrence, complications, and function after curettage versus resection for these patients. MATERIALS AND METHODS: We retrospectively studied the files of 46 patients with histologically confirmed GCTB of the extremities admitted and treated from 1982 to 2015. The median follow-up was 79.5 months (57.0-125.5 months). We evaluated local recurrence and type of surgery-related complications with imaging and function with the Musculoskeletal Tumor Society (MSTS) score. RESULTS: Overall local recurrence was 6.5%. There were one patient with curettage and two patients with resection; local recurrence rate was similar between the two procedures but the time to local recurrence was shorter after curettage. MSTS score was significantly better after curettage. Complications occurred in two patients after curettage and in five patients after resection; because of the low number of patients with complications, a statistical comparison was not possible; however, by direct comparison of the numbers, complications were more common after resection compared with curettage. CONCLUSION: Curettage is recommended for GCTB and pathological fracture at presentation because of similar local recurrence but better function compared with resection. The treating physicians should be aware and inform their patients for a shorter time to local recurrence after curettage and for more complications after resection.

Involvement of FFA1 and FFA4 in the regulation of cellular functions during tumor progression in colon cancer cells.

Free fatty acid receptor 1 (FFA1) and FFA4 mediate a variety of biological responses through binding of medium- and long-chain free fatty acids. The aim of this study was to investigate an involvement of FFA1 and FFA4 in the regulation of cellular functions during tumor progression in colon cancer cells. The long-term fluorouracil (5-FU) and cisplatin (CDDP) treated cells were generated from DLD1 cells (DLD-5FU and DLD-CDDP cells, respectively). FFAR1 expressions were lower in DLD-5FU and DLD-CDDP cells than in DLD1 cells. In contrast, DLD-5FU and DLD-CDDP cells showed the high FFAR4 expressions, compared with DLD1 cells. The cell motile activities of DLD-5FU and DLD-CDDP cells were reduced by GW9508 which is an agonist of FFA1 and FFA4. Moreover, GW1100, an antagonist of FFA1, inhibited the cell motile activities of DLD-5FU and DLD-CDDP cells. To evaluate whether FFA1 and FFA4 regulate the enhancement of cell motility, invasion and colony formation, highly migratory (hmDLD1) cells were established from DLD1 cells. FFAR1 expression was significantly higher in hmDLD1 cells than in DLD1 cells, but no change of FFAR4 expression was observed. The elevated cell motile and invasive activities and colony formation of hmDLD1 cells were suppressed by FFA1 inhibition. These results suggest that FFA1 and FFA4 are involved in the regulation of cellular functions during tumor progression in colon cancer DLD1 cells.

Involvement of LPA signaling via LPA receptor-2 in the promotion of malignant properties in osteosarcoma cells.

Lysophosphatidic acid (LPA) signaling via G protein-coupled LPA receptors mediates various biological effects in cancer cells. This study aimed to investigate the roles of LPA receptors in the regulation of cellular functions during tumor progression in osteosarcoma cells. Long-term cisplatin (CDDP)-treated MG63-C and MG63-R7-C cells were generated from osteosarcoma MG-63 and highly-migratory MG63-R7 cells, respectively. LPAR2 and LPAR3 expression levels were significantly higher in MG63-C cells than in MG-63 cells, while LPAR1 expression was reduced. MG63-C cells were highly motile, compared with MG-63 cells. MG63-C cell motility was suppressed by LPA2 knockdown and enhanced by the LPA1/LPA3 antagonist, dioctanoylglycerol pyrophosphate. LPAR2 and LPAR3 expression levels were significantly elevated in MG63-R7-C cells in comparison with MG63-R7 cells. MG63-R7-C cells were found to be highly invasive, correlating with metalloproteinase-2 activation. MG63-R7-C cells formed large colonies, whereas colony formation was absent from MG63-R7 cells. Notably, MG63-R7-C cell activities were inhibited by LPA2 knockdown. These results suggest that LPA signaling via LPA2 plays an important role in the acquisition of malignant properties during tumor progression in MG-63 cells.