Intraneural fibrosis within ilioinguinal nerve in inguinal hernia patients with preoperative pain: it's the sign of irreversible nerve injury, isn't it?

PURPOSE: Preoperative pain is known as one of the most powerful risk factors for chronic postoperative inguinal pain (CPIP), while its pathogenesis has not been fully elucidated. The aim of the present study was to evaluate patients with preoperative pain from the pathological perspective and discuss the potential pathogenesis of CPIP in those patients. METHODS: This was a single-institutional retrospective study. The study population was inguinal hernia patients with preoperative pain who underwent open anterior hernia repair for primary inguinal hernia with pragmatic ilioinguinal neurectomy during surgery between March 2021 and March 2023. The primary and secondary outcomes were proportion of collagen deposition and mucus accumulation within ilioinguinal nerve in those patients, respectively, which were evaluated histologically using Image J software. RESULTS: Forty patients were evaluated. Median value of proportion of intraneural collagen deposition was 38.3% (27.7-95.9). These values were positively correlated with the duration of pain (r2=0.468, P<0.001). Median value of proportion of mucus accumulation in ilioinguinal nerve was 50.1% (0-82.0). These values had no correlation with any clinicopathological variables. CONCLUSIONS: In the present study population, all patients with preoperative pain had intraneural fibrosis within ilioinguinal nerve, and its degree had a positive correlation with the pain duration.

Clinical Role of ASCT2 (SLC1A5) in KRAS-Mutated Colorectal Cancer.

Mutation in the KRAS gene induces prominent metabolic changes. We have recently reported that KRAS mutations in colorectal cancer (CRC) cause alterations in amino acid metabolism. However, it remains to be investigated which amino acid transporter can be regulated by mutated KRAS in CRC. Here, we performed a screening of amino acid transporters using quantitative reverse-transcription polymerase chain reaction (RT-PCR) and then identified that ASCT2 (SLC1A5) was up-regulated through KRAS signaling. Next, immunohistochemical analysis of 93 primary CRC specimens revealed that there was a significant correlation between KRAS mutational status and ASCT2 expression. In addition, the expression level of ASCT2 was significantly associated with tumor depth and vascular invasion in KRAS-mutant CRC. Notably, significant growth suppression and elevated apoptosis were observed in KRAS-mutant CRC cells upon SLC1A5-knockdown. ASCT2 is generally known to be a glutamine transporter. Interestingly, SLC1A5-knockdown exhibited a more suppressive effect on cell growth than glutamine depletion. Furthermore, SLC1A5-knockdown also resulted in the suppression of cell migration. These results indicated that ASCT2 (SLC1A5) could be a novel therapeutic target against KRAS-mutant CRC.

Targeting Asparagine Synthetase in Tumorgenicity Using Patient-Derived Tumor-Initiating Cells.

Reprogramming of energy metabolism is regarded as one of the hallmarks of cancer; in particular, oncogenic RAS has been shown to be a critical regulator of cancer metabolism. Recently, asparagine metabolism has been heavily investigated as a novel target for cancer treatment. For example, Knott et al. showed that asparagine bioavailability governs metastasis in a breast cancer model. Gwinn et al. reported the therapeutic vulnerability of asparagine biosynthesis in KRAS-driven non-small cell lung cancer. We previously reported that KRAS-mutated CRC cells can adapt to glutamine depletion through upregulation of asparagine synthetase (ASNS), an enzyme that synthesizes asparagine from aspartate. In our previous study, we assessed the efficacy of asparagine depletion using human cancer cell lines. In the present study, we evaluated the clinical relevance of asparagine depletion using a novel patient-derived spheroid xenograft (PDSX) mouse model. First, we examined ASNS expression in 38 spheroid lines and found that 12 lines (12/37, 32.4%) displayed high ASNS expression, whereas 26 lines (25/37, 67.6%) showed no ASNS expression. Next, to determine the role of asparagine metabolism in tumor growth, we established ASNS-knockdown spheroid lines using lentiviral short hairpin RNA constructs targeting ASNS. An in vitro cell proliferation assay demonstrated a significant decrease in cell proliferation upon asparagine depletion in the ASNS-knockdown spheroid lines, and this was not observed in the control spheroids lines. In addition, we examined asparagine inhibition with the anti-leukemia drug L-asparaginase (L-Asp) and observed a considerable reduction in cell proliferation at a low concentration (0.1 U/mL) in the ASNS-knockdown spheroid lines, whereas it exhibited limited inhibition of control spheroid lines at the same concentration. Finally, we used the PDSX model to assess the effects of asparagine depletion on tumor growth in vivo. The nude mice injected with ASNS-knockdown or control spheroid lines were administered with L-Asp once a day for 28 days. Surprisingly, in mice injected with ASNS-knockdown spheroids, the administration of L-Asp dramatically inhibited tumor engraftment. On the other hands, in mice injected with control spheroids, the administration of L-Asp had no effect on tumor growth inhibition at all. These results suggest that ASNS inhibition could be critical in targeting asparagine metabolism in cancers.

Orally Bioavailable Quinoxaline Inhibitors of 15-Prostaglandin Dehydrogenase (15-PGDH) Promote Tissue Repair and Regeneration.

15-Prostaglandin dehydrogenase (15-PGDH) regulates the concentration of prostaglandin E2 in vivo. Inhibitors of 15-PGDH elevate PGE2 levels and promote tissue repair and regeneration. Here, we describe a novel class of quinoxaline amides that show potent inhibition of 15-PGDH, good oral bioavailability, and protective activity in mouse models of ulcerative colitis and recovery from bone marrow transplantation.

Dual blockade of macropinocytosis and asparagine bioavailability shows synergistic anti-tumor effects on KRAS-mutant colorectal cancer.

Mutations of KRAS gene are found in various types of cancer, including colorectal cancer (CRC). Despite intense efforts, no pharmacological approaches are expected to be effective against KRAS-mutant cancers. Macropinocytosis is an evolutionarily conserved actin-dependent endocytic process that internalizes extracellular fluids into large vesicles called macropinosomes. Recent studies have revealed macropinocytosis's important role in metabolic adaptation to nutrient stress in cancer cells harboring KRAS mutations. Here we showed that KRAS-mutant CRC cells enhanced macropinocytosis for tumor growth under nutrient-depleted conditions. We also demonstrated that activation of Rac1 and phosphoinositide 3-kinase were involved in macropinocytosis of KRAS-mutant CRC cells. Furthermore, we found that macropinocytosis was closely correlated with asparagine metabolism. In KRAS-mutant CRC cells engineered with knockdown of asparagine synthetase, macropinocytosis was accelerated under glutamine-depleted condition, and albumin addition could restore the glutamine depletion-induced growth suppression by recovering the intracellular asparagine level. Finally, we discovered that the combination of macropinocytosis inhibition and asparagine depletion dramatically suppressed the tumor growth of KRAS-mutant CRC cells in vivo. These results indicate that dual blockade of macropinocytosis and asparagine bioavailability could be a novel therapeutic strategy for KRAS-mutant cancers.

Disruption of CCR1-mediated myeloid cell accumulation suppresses colorectal cancer progression in mice.

Tumor-stromal interaction is implicated in tumor progression. Although CCR1 expression in myeloid cells could be associated with pro-tumor activity, it remains elusive whether disruption of CCR1-mediated myeloid cell accumulation can suppress tumor progression. Here, we investigated the role of CCR1 depletion in myeloid cells in two syngeneic colorectal cancer mouse models: MC38, a transplanted tumor model and CMT93, a liver metastasis model. Both cells induced tumor accumulation of CCR1+ myeloid cells that express MMP2, MMP9, iNOS, and VEGF. Lack of the Ccr1 gene in host mice dramatically reduced MC38 tumor growth as well as CMT93 liver metastasis. To delineate the contribution of CCR1+ myeloid cells, we performed bone marrow (BM) transfer experiments in which sub-lethally irradiated wild-type mice were reconstituted with BM from either wild-type or Ccr1-/- mice. Mice reconstituted with Ccr1-/- BM exhibited marked suppression of MC38 tumor growth and CMT93 liver metastasis, compared with control mice. Consistent with these results, administration of a neutralizing anti-CCR1 monoclonal antibody, KM5908, significantly suppressed MC38 tumor growth and CMT93 liver metastases. Our findings highlight the importance of the application of CCR1 blockade as a therapeutic strategy.

Bone marrow-derived mesenchymal stem cells promote colorectal cancer progression via CCR5.

Mesenchymal stem cells (MSCs) are recruited from BM to the stroma of developing tumors, where they serve as critical components of the tumor microenvironment by secreting growth factors, cytokines, and chemokines. The role of MSCs in colorectal cancer (CRC) progression was controversial. In this study, we found that C-C chemokine receptor type 5 (CCR5) ligands (i.e., C-C motif chemokine ligand 3 (CCL3), CCL4, and CCL5) were highly produced from MSCs using a chemokine array screening with conditioned media from the cultured human MSCs. A relatively strong CCR5 expression could be detected within the cytoplasm of several CRC cell lines. Regarding the effect of MSC, we found that the xenografts in which CCR5-overexpressing HCT116 cells were inoculated into immunocompromised mice were highly promoted in vivo by a mixture with MSCs. Notably, the CCR5 inhibitor, maraviroc, significantly abolished the MSC-induced tumor growth in vivo. In human clinical specimens (n = 89), 20 cases (29%) were high for CCR5, whereas 69 cases (71%) were low. Statistical analyses indicated that CCR5 expression in primary CRC was associated with CRC patients' prognosis. Especially, stage III/IV patients with CCR5-high CRCs exhibited a significantly poorer prognosis than those with CCR5-low CRCs. Furthermore, we investigated the effects of preoperative serum CCR5 ligands on patients' prognosis (n = 114), and found that CRC patients with high serum levels of CCL3 and CCL4 exhibited a poorer prognosis compared to those with low levels of CCL3 and CCL4, while there was no association between CCL5 and prognosis. These results suggest that the inhibition of MSC-CRC interaction by a CCR5 inhibitor could provide the possibility of a novel therapeutic strategy for CRC, and that serum levels of CCL3 and CCL4 could be predictive biomarkers for the prognosis of CRC patients.

Loss of SMAD4 Promotes Colorectal Cancer Progression by Recruiting Tumor-Associated Neutrophils via the CXCL1/8-CXCR2 Axis.

PURPOSE: SMAD4 is a key transcriptional factor of TGFß signaling and acts as a tumor suppressor in colorectal cancer. In the present study, we explored the immunologic effect of SMAD4 on the tumor microenvironment. EXPERIMENTAL DESIGN: Using 99 clinical specimens and human colorectal cancer cell lines, we investigate the relationship between SMAD4 expression and neutrophil accumulation. We immunohistochemically analyzed expression of SMAD4, CXCL1, CXCL8, CXCR2, and other proteins with clinical specimens. Finally, we determined the serum levels of CXCL1 and CXCL8 in 125 patients with colorectal cancer. RESULTS: SMAD4 knockdown from human colorectal cancer cells upregulated the expression of CXCL1 and CXCL8, which recruited neutrophils to colorectal cancer tumor via CXCR2. In turn, when neutrophils were exposed to the supernatant of SMAD4-negative colorectal cancer cells, they produced a large amount of CXCL1 and CXCL8 by themselves in vitro. In human clinical specimens, we found that neutrophil infiltration into the peritumoral stroma was more marked in SMAD4-negative colorectal cancer compared with that in SMAD4-positive colorectal cancer, and that both CXCL1 and CXCL8 were abundantly expressed in the tumor-infiltrating neutrophils. Neutrophils isolated from primary colorectal cancer expressed significantly higher levels of CXCL1 and CXCL8 than did those isolated from peripheral blood. Furthermore, tumor-infiltrating neutrophils expressed MMP2 and MMP9 in addition to ARG1 and IDO. Serum CXCL8 level was significantly higher in colorectal cancer patients, especially those at stage II/III, and statistical analysis indicated a high CXCL8 level was associated with a shorter overall survival and relapse-free survival. CONCLUSIONS: Blockade of the CXCL1/8-CXCR2 axis could be a novel therapeutic approach against SMAD4-negative colorectal cancer.

Dedifferentiated liposarcoma involving the spleen and splenic hilum: a report of a case with a rare growth pattern.

We present a rare case of dedifferentiated liposarcoma confined to the spleen and splenic hilum. An 81-year-old man was referred to our hospital with a large asymptomatic splenic tumor. The patient underwent splenectomy, and the adipose tissue surrounding the splenic hilum was also resected. Microscopically, the tumor mainly consisted of high-grade spindle cells similar to those seen in undifferentiated pleomorphic liposarcoma. In the splenic hilum, scattered atypical cells were detected in the sclerosing component and adipose tissue. Immunohistochemically, both the spindle cells in the spleen and the atypical cells in the splenic hilum were positive for MDM2 and CDK4. The histopathologic diagnosis was dedifferentiated liposarcoma derived from an atypical lipomatous tumor/well-differentiated liposarcoma of the adipose tissue in the splenic hilum with extension into the spleen. Dedifferentiated liposarcoma in the spleen and splenic hilum should be considered as a differential diagnosis of splenic tumors.