Combination Methionine-methylation-axis Blockade: A Novel Approach to Target the Methionine Addiction of Cancer

BACKGROUND/AIM

Cancers are selectively sensitive to methionine (MET) restriction (MR) due to their addiction to MET which is overused for elevated methylation reactions. MET addiction of cancer was discovered by us 45 years ago. MR of cancer results in depletion of S-adenosylmethionine (SAM) for transmethylation reactions, resulting in selective cancer-growth arrest in the late S/G₂-phase of the cell cycle. The aim of the present study was to determine if blockade of the MET-methylation axis is a highly-effective strategy for cancer chemotherapy.

MATERIALS AND METHODS

In the present study, we demonstrated the efficacy of MET-methylation-axis blockade using MR by oral-recombinant methioninase (o-rMETase) combined with decitabine (DAC), an inhibitor of DNA methylation, and an inhibitor of SAM synthesis, cycloleucine (CL). We determined a proof-of-concept of the efficacy of the MET-methylation-axis blockade on a recalcitrant undifferentiated/unclassified soft-tissue sarcoma (USTS) patient-derived orthotopic xenograft (PDOX) mouse model.

RESULTS

The o-rMETase-CL-DAC combination regressed the USTS PDOX with extensive cancer necrosis.

CONCLUSION

The new concept of combination MET-methylation-axis blockade is effective and can now be tested on many types of recalcitrant cancer.

Comparison of the Efficacy of EGFR Tyrosine Kinase Inhibitors Erlotinib and Low-dose Osimertinib on a PC-9-GFP EGFR Mutant Non-small-cell Lung Cancer Growing in the Brain of Nude Mice

BACKGROUND/AIM

Brain metastases are found in approximately 30% of patients with epidermal-growth-factor receptor (EGFR) mutant non-small cell lung cancer (NSCLC). We compared the efficacy of two EGFR-tyrosine kinase inhibitors (TKIs), erlotinib and osimertinib on a PC-9-GFP EGFR mutant NSCLC growing in the brain of nude mice.

MATERIALS AND METHODS

The brain metastasis models were randomized into five groups and treated for 15 days: Control; 5 mg/kg erlotinib; 50 mg/kg erlotinib; 0.5 mg/kg osimertinib; 5 mg/kg osimertinib. Tumor volume was evaluated by non-invasive fluorescence imaging.

RESULTS

Only 5 mg/kg osimertinib, a low-dose compared to the clinically-equivalent dose, showed significant tumor regression compared to the control.

CONCLUSION

This study strongly supports the high activity of osimertinib for intracranial lesions of EGFR-mutant NSCLC.

Eribulin Regresses a Doxorubicin-resistant Dedifferentiated Liposarcoma in a Patient-derived Orthotopic Xenograft Mouse Model

BACKGROUND/AIM

Dedifferentiated liposarcoma (DDLPS) is recalcitrant type of sarcoma. DDLPS has a low survival rate with high recurrence and metastasis. In the present study, we evaluated the efficacy of several drugs against doxorubicin-resistant DDLPS in a patient-derived orthotopic xenograft (PDOX) model for precision oncology. To establish the PDOX model, a tumor from a patient who had recurrent high-grade DDLPS from the retroperitoneum was previously grown orthotopically in the retroperitoneum of nude mice.

MATERIALS AND METHODS

We randomized DDLPS PDOX models into 8 treatment groups when tumor volume became approximately 100 mm³: control, no treatment; G2, doxorubicin (DOX); G3, pazopanib (PAZ); G4, gemcitabine (GEM) combined with docetaxel (DOC); G5, trabectedin (YON); G6, temozolomide (TEM); G7, palbociclib (PAL); G8, eribulin (ERB). Tumor length and width were measured both at the beginning and at the end of treatment.

RESULTS

At the end of treatment (day 14), all treatments significantly inhibited DDLPS PDOX tumor growth compared to the untreated control, except DOX. ERB was significantly more effective and regressed tumor volume compared to other treatments on day 14 after initiation of treatment. No significant differences were found in the relative body weight on day 14 compared to day 0 in any group.

CONCLUSION

The clinical potential of ERB against DDLPS is herein presented in a PDOX model.

Decay score: A guide to the immunoreactivity of human pancreatic islets in autopsy specimen

BACKGROUND

The pancreas is an exo-endocrine organ that undergoes rapid autolysis soon after death, which limits its utility in academics and research. The timeline of autolytic changes of pancreatic islets and its immunoreactivity is limited in the literature. Decay score has been used to grade the autolytic changes in organs like the brain, lung and liver. However, reports are not available in the pancreas/ pancreatic islets. Knowledge regarding the decay score may be used as a torchbearer for the immunoreactivity of human pancreatic islets in autopsy cases. The present study is aimed to provide an optimal cut-off time based on the decay score before which pancreatic specimens should be collected for the purpose of immunohistochemical studies of pancreatic islets.

MATERIALS AND METHODS

Serial sections of twenty adult human pancreas obtained from the autopsy were subjected to H&E and immunohistochemical staining. Autolytic changes of pancreatic islets were graded by using decay score in H&E sections, which was compared with the results of the immunohistochemical reactivity of pancreatic islets in IHC sections.

RESULTS AND CONCLUSIONS

Pancreatic islets immunoreactivity was found to be well preserved in the samples collected early within 9 h with a decay score of less than 1.4. There was an inverse relation of decay score and immunoreactivity of pancreatic islets. The decay score of less than 1.4 has better-preserved immunoreactivity than having more than 1.4. This knowledge will help researchers working in the field of the endocrine pancreas.

A Novel Anionic-phosphate-platinum Complex Effectively Targets a Cisplatinum-resistant Osteosarcoma in a Patient-derived Orthotopic Xenograft Mouse Model

BACKGROUND/AIM

We have previously developed a novel bone-targeting platinum compound, 3Pt, and showed that it has strong inhibitory activity against osteosarcoma cells and orthotopic cell-line xenograft mouse models. In the present report, we compared the efficacy of 3Pt to cisplatinum (CDDP) in a CDDP-resistant relapsed osteosarcoma patient-derived orthotopic xenograft (PDOX) mouse model.

PATIENTS AND METHODS

The tumor of a patient with osteosarcoma of the distal femur was treated with CDDP-based chemotherapy followed by surgery. The surgical specimen was used to establish a PDOX model. An osteosarcoma cell line was also established from the original patient tumor. Osteosarcoma cell viability was assessed with the WST-8 assay and the IC50 values were calculated. The PDOX models were randomized into three groups: untreated control, CDDP-treated group, and 3Pt-treated group. Tumor size and body weight were measured twice a week.

RESULTS

3Pt had a strong concentration-dependent cytocidal effect in vitro. The IC₅₀ value of 3Pt was significantly lower than that of CDDP. On day 14 of the treatment, 3Pt caused a significantly greater tumor growth inhibition compared to the untreated control and CDDP-treated mice.

CONCLUSION

3Pt is a promising clinical candidate for the treatment of recalcitrant osteosarcoma.

A novel patient-derived orthotopic xenograft (PDOX) mouse model of highly-aggressive liver metastasis for identification of candidate effective drug-combinations

Liver metastasis is a recalcitrant disease that usually leads to death of the patient. The present study established a unique patient-derived orthotopic xenograft (PDOX) nude mouse model of a highly aggressive liver metastasis of colon cancer. The aim of the present study was to demonstrate proof-of-concept that candidate drug combinations could significantly inhibit growth and re-metastasis of this recalcitrant tumor. The patient’s liver metastasis was initially established subcutaneously in nude mice and the subcutaneous tumor tissue was then orthotopically implanted in the liver of nude mice to establish a PDOX model. Two studies were performed to test different drugs or drug combination, indicating that 5-fluorouracil (5-FU) + irinotecan (IRI) + bevacizumab (BEV) and regorafenib (REG) + selumetinib (SEL) had significantly inhibited liver metastasis growth (p = 0.013 and p = 0.035, respectively), and prevented liver satellite metastasis. This study is proof of concept that a PDOX model of highly aggressive colon-cancer metastasis can identify effective drug combinations and that the model has future clinical potential.

Ischemia reperfusion-induced metastasis is resistant to PPARγ agonist pioglitazone in a murine model of colon cancer

Ischemia reperfusion injury (IRI) during liver-metastasis resection for treatment of colon cancer may increase the risk of further metastasis. Peroxisome proliferator-activated receptor-γ (PPARγ) activation has been observed to exert a protective effect against IRI and IRI-induced metastasis of hepatocellular carcinoma. The present study aimed to investigate the effect of the PPARγ agonist pioglitazone on tumor metastasis and liver injury following IRI in a mouse model of colon cancer. Pioglitazone (30 mg/kg weight) was administered orally 1.5 h before and 2 h after the initiation of ischemia and was orally administrated daily to mice from day 0–21. SL4-cancer cells expressing red fluorescent protein (SL4-RFP) (1 × 10⁶) were injected into the spleen. Fifteen minutes after injection, the hepatoduodenal ligament was clamped with a vessel clip, and released 5 min later. Liver, blood and tumor samples were taken from mice in order to determine if inflammation was induced by IRI. The effect of pioglitazone on liver metastasis was assessed. Furthermore, the effect of pioglitazone to control the inflammatory response during IRI progression was examined. Liver metastasis along with MMP-9 activation and the production of inflammatory cytokines were resistant to pioglitazone. Our results indicate that liver metastasis and associated inflammation in mice were resistant to pioglitazone.

Pazopanib Inhibits Tumor Growth, Lymph-node Metastasis and Lymphangiogenesis of an Orthotopic Mouse of Colorectal Cancer

BACKGROUND/AIM

Pazopanib (PAZ) can inhibit tumor progression, but whether PAZ inhibits lymph node metastasis and lymphangiogenesis in colorectal cancer is still unknown. The aim of the present study was to determine the efficacy of PAZ on tumor growth, lymph node metastasis and lymphangiogenesis in an orthotopic nude mouse model in colorectal cancer.

MATERIALS AND METHODS

CT-26-green fluorescence protein (GFP)-expressing mouse colon cancer cells were injected into nude mice to establish a subcutaneous colorectal cancer model and were treated with saline and PAZ. Additionals subcutaneous tumors were harvested and cut into 5 mm³ fragments, then tumor fragments were implanted orthotopically in the cecum to establish an orthotopic colorectal-cancer nude mouse model. Orthotopic mice were randomized into two groups for the treatment with saline and PAZ, respectively. Tumor width, length and mouse body weight was measured twice a week. The Fluor Vivo imaging system was used to image the GFP. Hematoxylin & eosin staining and immunohistochemical staining was used for histological analysis.

RESULTS

PAZ inhibited the growth of subcutaneous colorectal cancer, as wells as orthotopic transplanted colorectal cancer tumors. PAZ suppressed lymph node metastasis and lymphangiogenesis in the orthotopic colon cancer model. No significant changes were observed in the body weight between the control and the mice treated with PAZ.

CONCLUSION

PAZ can inhibit the growth of colorectal cancer and inhibit lymph node metastasis and lymphangiogenesis in orthotopic colon cancer nude mouse models.

Oral recombinant methioninase increases TRAIL receptor-2 expression to regress pancreatic cancer in combination with agonist tigatuzumab in an orthotopic mouse model

Methionine addiction is a fundamental and general hallmark of cancer. Gene expression analysis showed that methionine restriction (MR) of methionine-addicted cancer cells increases TNF-related apoptosis-induced ligand receptor-2 (TRAIL-R2) expression. Here, we determined the effects of MR on TRAIL-R2 targeted therapy in pancreatic cancer by the TRAIL-R2 agonist tigatuzumab. Human pancreatic cancer cell lines were cultured in control or methionine-free medium. The effects of MR on TRAIL-R2 expression and sensitivity to tigatuzumab were evaluated in vitro. An orthotopic pancreatic cancer mouse model was established to evaluate the efficacy of MR using oral recombinant methioninase (o-rMETase), and the efficacy of tigatuzumab and their combination. MR enabled tigatuzumab-induced apoptosis, by increasing TRAIL-R2 expression in pancreatic cancer cells in vitro. The protein expression level of the melanoma-associated antigen MAGED2, which reduces TRAIL-R2 expression, was decreased by MR. In the orthotopic pancreatic cancer mouse model, o-rMETase increased TRAIL-R2 expression level in the tumors and enabled the antitumor efficacy of tigatuzumab. MR, effected by o-rMETase, enabled the efficacy of the TRAIL-R2 agonist tigatuzumab by increasing TRAIL-R2 expression in pancreatic cancer. Our results suggest that o-rMETase has clinical potential for treating pancreatic cancer.

Hair-Follicle-Associated Pluripotent (HAP) Stem Cells Encapsulated on Polyvinylidene Fluoride Membranes (PFM) Promote Functional Recovery from Spinal Cord Injury

Our previous studies showed that nestin-expressing hair follicle-associated-pluripotent (HAP) stem cells, which reside in the bulge area of the hair follicle, could restore injured nerve and spinal cord and differentiate into cardiac muscle cells. Here we transplanted mouse green fluorescent protein (GFP)-expressing HAP stem-cell colonies enclosed on polyvinylidene fluoride membranes (PFM) into the severed thoracic spinal cord of nude mice. After seven weeks of implantation, we found the differentiation of HAP stem cells into neurons and glial cells. Our results also showed that PFM-captured GFP-expressing HAP stem-cell colonies assisted complete reattachment of the thoracic spinal cord. Furthermore, our quantitative motor function analysis with the Basso Mouse Scale for Locomotion (BMS) score demonstrated a significant improvement in the implanted mice compared to non-implanted mice with a severed spinal cord. Our study also showed that it is easy to obtain HAP stem cells, they do not develop teratomas, and do not loose differentiation ability when cryopreserved. Collectively our results suggest that HAP stem cells could be a better source compared to induced pluripotent stem cells (iPS) or embryonic stem (ES) cells for regenerative medicine, specifically for spinal cord repair.

Osimertinib regressed an EGFR-mutant lung-adenocarcinoma bone-metastasis mouse model and increased long-term survival

Bone is one of the most frequent metastatic sites in non-small cell lung cancer (NSCLC). Osimertinib, with and without bevacizumab (BV), has been investigated on advanced NSCLC patients. However, the efficacy of those drugs on bone metastasis of NSCLC has not been investigated. The human NSCLC cell line H1975, expressing red fluorescent protein (H1975-RFP), was orthotopically injected to the tibia of nude mice. The established mouse models were randomized into four treatment groups of nine mice: Control; BV alone; osimertinib alone; osimertinib and BV combination. The tumors were observed by non-invasive fluorescence imaging. Osimertinib, with or without BV, caused tumor regression, increased mouse survival, and bone remodeling in the bone metastasis models. These results suggest that osimertinib is a promising clinical option for NSCLS patients with bone metastasis.

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Bone is a frequent metastatic site in non-small cell lung cancer (NSCLC).

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Established imageable orthotopic xenograft mouse model for NSCLC

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Osimertinib and osimertinib + BV regressed the NSCLC bone metastasis.

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Osimertinib and osimertinib + BV increased mouse survival and bone remodeling.

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Osimertinib is a promising clinical option for NSCLS patients with bone metastasis.

TRAF6-Mediated Inflammatory Cytokines Secretion in LPS-induced Colorectal Cancer Cells Is Regulated by miR-140

BACKGROUND/AIM

Colorectal cancer (CRC) cells secrete inflammatory cytokines that affect CRC progression. The aim of the present study was to determine if micro-RNA-140(miR-140) regulates inflammatory cytokine secretion induced by lipopolysaccharide (LPS) in colorectal cancer cells by targeting tumor necrosis factor receptor (TNFR)-associated factor 6 (TRAF6).

MATERIALS AND METHODS

Fifty fresh colon-cancer specimens and normal colorectal tissues were collected from patients with CRC and tested for the expression miR-140. Human CRC cell lines SW480 and HCT116 were treated with various concentrations and times with LPS. miR-140 and mRNA expression of potentially related genes were analyzed by qPCR. Protein expression was analyzed using western blot or ELISA. Overexpression plasmids with pcDNA3.1-TRAF6, pGL4.10-wtTRAF6 and pGL4.10-mutTRAF6 were constructed. miRNA target gene prediction and a dual luciferase assay were used to analyze miR-140-targeted TRAF6.

RESULTS

miR-140 expression was up-regulated in CRC tissues. In CRC cells, LPS could increase miR-140 expression in a time- and concentration-dependent manner. LPS increased inflammatory cytokine mRNA expression levels in SW480 and HCT116 human colon-cancer cells. miRNA-140 suppressed TRAF6 expression via targeting the 3'UTR. TRAF6 affected miR-140-mediated inflammatory cytokine expression of SW480 and HCT116 cells under LPS treatment.

CONCLUSION

miR-140 regulates inflammatory cytokine secretion of LPS-induced colorectal cancer cells by targeting TRAF6.

PPARγ Agonist Pioglitazone in Combination With Cisplatinum Arrests a Chemotherapy-resistant Osteosarcoma PDOX Model

BACKGROUND/AIM

Cisplatinum (CDDP) is a first-line drug in osteosarcoma treatment and the acquisition of resistance to CDDP is associated with a poor prognosis. Peroxisome proliferator-activated receptor gamma (PPARγ) is a nuclear hormone receptor that plays important roles in cell proliferation, differentiation, development, metabolism and cell death. Recently, PPARγ was reported to enhance the efficacy, overcome resistance, and decrease the toxicity of CDDP in various human cancers. In this study we tested whether pioglitazone (PIO), a PPARγ agonist, could overcome CDDP resistance in osteosarcoma.

MATERIALS AND METHODS

In this study, we used a human osteosarcoma cell line and a patient-derived orthotopic xenograft (PDOX) models of osteosarcoma. We measured cell viability of 143B human osteosarcoma cells when treated with CDDP and PIO. We randomized PDOX models of osteosarcoma into four treatment groups: Group 1, Untreated control; Group 2, PIO alone; Group 3, CDDP alone; Group 4, a combination of CDDP and PIO. Each group comprised six mice. Mice were treated for 14 days and tumor size and body weight were measured.

RESULTS

Cell viability of 143B human osteosarcoma cells was significantly reduced when PIO (50 μmol/l) was combined with CDDP compared to CDDP alone. PDOX osteosarcoma tumors treated with the CDDP-PIO combination showed the strongest tumor growth inhibition compared to other treatment groups. PDOX osteosarcoma tumors treated with the CDDP-PIO combination had the least cancer cells and the most necrosis in histological section.

CONCLUSION

These results suggest that combining PIO along with CDDP could be an effective treatment strategy for osteosarcoma and has important clinical potential for patients.

A Triple-negative Matrix-producing Breast Carcinoma Patient-derived Orthotopic Xenograft (PDOX) Mouse Model Is Sensitive to Bevacizumab and Vinorelbine, Regressed by Eribulin and Resistant to Olaparib

BACKGROUND/AIM

Matrix-producing breast carcinoma (MPBC) is a rare and usually aggressive triple-negative breast cancer (TNBC). In this study, we determined drug sensitivity for a triple-negative MPBC, without BRCA mutations, in a patient-derived orthotopic xenograft (PDOX) model.

MATERIALS AND METHODS

The MPBC PDOX model was established in the left 2^nd mammary gland of nude mouse by implantation of the patient tumor using surgical orthotopic implantation (SOI). We randomized MPBC PDOX mice into 5 groups (n=5 mice/per treatment group) when the tumor volume reached 80 mm³: G1, control-no treatment; G2, bevacizumab [intra-peritoneal (i.p.), weekly, for 2 weeks]; G3, vinorelbine (i.p., weekly, for 2 weeks); G4, olaparib (oral., daily, for 2 weeks); G5, eribulin [intravenous (i.v.), weekly, for 2 weeks]. The mice in each treatment group were sacrificed on day 15. Tumor volume and body weight were measured once/week.

RESULTS

The MPBC PDOX model was resistant to olaparib (p=0.22). The MPBC PDOX model treated with bevacizumab and vinorelbine showed significantly suppressed tumor growth compared to the untreated group (p=0.005 and 0.002, respectively). However, only eribulin regressed the tumor (p=0.0001). Eribulin was more effective than olaparib (p=0.0001), bevacizumab (p=0.0025) and vinorelbine (p=0.0061).

CONCLUSION

Eribulin has clinical potential as treatment for triple-negative MPBC patients that are resistant to a PARP inhibitor such as olaparib.

Eribulin Regresses a Cisplatinum-resistant Rare-type Triple-negative Matrix-producing Breast Carcinoma Patient-derived Orthotopic Xenograft Mouse Model

BACKGROUND/AIM

Matrix-producing breast carcinoma (MPBC) is a rare and usually aggressive triple-negative breast cancer (TNBC). In the present report, we determined the drug sensitivity for a triple-negative MPBC using a patient-derived orthotopic xenograft (PDOX) model.

MATERIALS AND METHODS

The PDOX model was established in the left 2^nd mammary by surgical orthotopic implantation (SOI). MPBC PDOX models were randomized into 4 groups (6 mice per group) when the tumor volume became 80 mm³: G1, control group; G2, cisplatinum group [intraperitoneal (i.p.) injection, weekly, for 2 weeks]; G3, paclitaxel group (i.p., weekly, for 2 weeks); G4, eribulin group [intravenous (i.v.) injection, weekly, for 2 weeks]. All mice were sacrificed on day 15. Tumor volume and body weight were measured one time per week.

RESULTS

The MPBC PDOX model was resistant to cisplatinum (p=0.800). Paclitaxel suppressed tumor growth compared to the control group (p=0.009). However, only eribulin regressed the tumor (p=0.001).

CONCLUSION

Eribulin has clinical potential for triple-negative MPBC patients.

A Single Low Dose of Eribulin Regressed a Highly Aggressive Triple-negative Breast Cancer in a Patient-derived Orthotopic Xenograft Model

BACKGROUND/AIM

In the present study, the breast cancer patient-derived orthotopic xenograft (PDOX) model was used to identify an effective drug for a highly aggressive triple negative breast cancer (TNBC).

MATERIALS AND METHODS

The TNBC tumor from a patient was implanted in the right 4th inguinal mammary fat pad of nude mice to establish a PDOX model. Three weeks later, 19 mice were randomized into the untreated-control group (n=10) and the eribulin treatment group (n=9, eribulin, 0.3 mg/kg, i.p., day 1).

RESULTS

On day 8, eribulin significantly inhibited tumor volume compared to the control group (p<0.01). Eribulin regressed tumors in 3 mice (33.3%) and apparently eradicated them in 6 mice (66.7%). At day 14, tumor regrowth was observed in 2 mice of the eribulin group, which was undetectable on day 8. However, 44.4% (4 out of 9) of the mice in the eribulin group were tumor-free on day 14.

CONCLUSION

A single low-dose eribulin was efficacious on a highly aggressive TNBC. The breast cancer PDOX model can be used to identify highly effective drugs for TNBC.

Recombinant Methioninase Combined With Tumor-targeting Salmonella typhimurium A1-R Induced Regression in a PDOX Mouse Model of Doxorubicin-resistant Dedifferentiated Liposarcoma

BACKGROUND/AIM

Dedifferentiated liposarcoma (DDLPS) is associated with a poor survival rate even with multi-modality treatment. In the present study, we evaluated the efficacy of recombinant methioninase (rMETase) combined with tumor-targeting Salmonella typhimurium (S. typhimurium) A1-R against a doxorubicin-resistant DDLPS in a patient-derived orthotopic xenograft (PDOX) mouse model.

MATERIALS AND METHODS

A recurrent high-grade DDLPS from the right retroperitoneum of a patient was grown orthotopically in the retroperitoneum of nude mice to establish a PDOX model. The PDOX models were randomly divided into the following groups: Control, no treatment; doxorubicin monotherapy; rMETase monotherapy; S. typhimurium A1-R monotherapy; S. typhimurium A1-R and rMETase combination therapy. Tumor length and width were measured before and after treatment.

RESULTS

On day 14 after treatment, all treatments significantly inhibited DDLPS PDOX tumor growth compared to the untreated control except for doxorubicin monotherapy. rMETase combined with S. typhimurium A1-R was significantly more effective and regressed tumor volume compared to either rMETase or S. typhimurium A1-R alone. The relative body weight did not significantly differ between days 0 and 14 for individual groups.

CONCLUSION

The combination of rMETase and S. typhimurium A1-R has important clinical potential for this recalcitrant sarcoma.

MyD88 Regulates LPS-induced NF-ĸB/MAPK Cytokines and Promotes Inflammation and Malignancy in Colorectal Cancer Cells

BACKGROUND/AIM

Inflammation may play a role in cancer initiation and progression. The molecular mechanisms by which inflammation causes colorectal cancer, remains unclear. The present study investigated a signaling pathway that affects inflammation in colorectal cancer.

MATERIALS AND METHODS

SW480 cells, HCT116 cells, and cells with knockdown of myeloid differentiation 88 (MyD88), and forced expression of MyD88 were treated with lipopolysaccharide (LPS; 1 μg/ml). Inflammation-related mRNA expression was analyzed by the quantitative reverse transcription polymerase chain reaction and inflammatory cytokines were detected by western blotting. The enzyme-linked immunosorbent assay (ELISA) was used to quantify inflammation-related cytokines in colorectal cancer cells. Cancer cell properties were evaluated using the wound-healing assay, transwell migration assay, transwell invasion assay, colony-formation assay, and CCK-8 assay.

RESULTS

LPS up-regulated mRNA and protein levels of inflammatory factors in colorectal cancer cells. Knockdown of MyD88 inhibited LPS-induced mRNA expression and inflammatory protein expression in colorectal cancer cells. Similarly, silencing of MyD88 expression suppressed LPS-induced changes in the biological behavior of colorectal cancer cells. Silencing of MyD88 expression down-regulated expression of proteins of the LPS/nuclear factor kappa-light-chain-enhancer of activated B-cells (NF-ĸB)/mitogen-activated protein kinase (MAPK) signaling pathway. Restoration of the expression of MyD88 reversed the effects in LPS-treated HCT116 cells.

CONCLUSION

MyD88-regulated LPS/NF-ĸB/MAPK signaling pathway affects the inflammatory and biological behavior of LPS-induced colorectal cancer cells.

Exquisite Tumor Targeting by Salmonella A1-R in Combination with Caffeine and Valproic Acid Regresses an Adult Pleomorphic Rhabdomyosarcoma Patient-Derived Orthotopic Xenograft Mouse Model

Adult pleomorphic rhabdomyosarcoma (RMS) is a rare and malignant mesenchymal tumor. Recently, we developed a patient-derived orthotopic xenograft (PDOX) model of adult pleomorphic RMS. In the present study, we evaluated the efficacy of tumor-targeting Salmonella typhimurium (S. typhimurium) A1-R combined with caffeine (CAF) and valproic acid (VPA) on the adult RMS PDOX. An adult pleomorphic RMS cell line was established from the PDOX model. Cell survival after exposure to CAF and VPA was assessed, and the IC₅₀ value was calculated for each drug. The RMS PDOX models were randomized into five groups: untreated control; tumor treated with cyclophosphamide (CPA); tumor treated with CAF + VPA; tumor treated with S. typhimurium A1-R; and tumor treated with S. typhimurium A1-R + CAF + VPA. Tumor size and body weight was measured twice a week. VPA caused a concentration-dependent cytocidal effect. A synergistic effect of combination treatment with CAF was observed against the RMS cell line. For the in vivo study, all treatments significantly inhibited tumor growth compared with the untreated control. S. typhimurium A1-R combined with VPA and CAF was significantly more effective than CPA, VPA combined with CAF, or S. typhimurium A1-R alone and significantly regressed the tumor volume compared with day 0. These results suggest that S. typhimurium A1-R together with VPA and CAF could regresses an adult pleomorphic RMS in a PDOX model and therefore has important future clinical potential.

Combination of Trabectedin With Irinotecan, Leucovorin and 5-Fluorouracil Arrests Primary Colorectal Cancer in an Imageable Patient-derived Orthotopic Xenograft Mouse Model

BACKGROUND/AIM

The aim of the present study was to determine the efficacy of trabectedin combined with FOLFIRI (irinotecan, leucovorin and 5-fluorouracil) on a colorectal cancer (CRC) patient-derived orthotopic xenograft (iPDOX) mouse model.

MATERIALS AND METHODS

A CRC tumor from a patient previously established in nude mice was implanted subcutaneously in transgenic green fluorescence protein (GFP)-expressing nude mice in order to label the tumor stromal cells with GFP. Mice were randomized into four groups: Group 1, untreated control; group 2, FOLFIRI; group 3, trabectedin alone; group 4, trabectedin plus FOLFIRI. Tumor width, length, and mouse body weight was measured twice every week.

RESULTS

All three treatment groups showed inhibited tumor growth compared to the untreated control group. Only the combination of FOLFIRI and trabectedin arrested tumor growth. No significant changes was observed in body weight in any group.

CONCLUSION

These findings suggest that the combination of trabectedin plus FOLFIRI has clinical potential for patients with CRC.

Combination of oral recombinant methioninase and decitabine arrests a chemotherapy-resistant undifferentiated soft-tissue sarcoma patient-derived orthotopic xenograft mouse model

Cancer cells are methionine (MET) and methylation addicted and are highly sensitive to MET restriction. The present study determined the efficacy of oral-recombinant methioninase (o-rMETase) and the DNA methylation inhibitor, decitabine (DAC) on restricting MET in an undifferentiated-soft tissue sarcoma (USTS) patient-derived orthotopic xenograft (PDOX) nude-mouse model. The USTS PDOX models were randomized into five treatment groups of six mice: Control; doxorubicin (DOX) alone; DAC alone; o-rMETase alone; and o-rMETase-DAC combination. Tumor size and body weight were measured during the 14 days of treatment. Tumor growth was arrested only in the o-rMETase-DAC condition. Tumors treated with the o-rMETase-DAC combination exhibited tumor necrosis with degenerative changes. This study demonstrates that the o-rMETase-DAC combination could arrest the USTS PDOX tumor suggesting clinical promise.

Combination of Trabectedin With Oxaliplatinum and 5-Fluorouracil Arrests a Primary Colorectal Cancer in a Patient-derived Orthotopic Xenograft Mouse Model

BACKGROUND/AIM

In the present study, we aimed to determine the efficacy of trabectedin (TRAB) combined with oxaliplatinum (OXA)+5-fluorouracil (5-FU) on a colorectal cancer (CRC) patient-derived orthotopic xenograft (PDOX) mouse model.

MATERIALS AND METHODS

A patient CRC tumor previously established in nude mice was implanted subcutaneously in transgenic green fluorescence protein (GFP)-expressing nude mice. Harvested tumor fragments were transplanted orthotopically in non-transgenic nude mice. Mice were randomized into three groups: Group 1 (G1), untreated-control; Group 2 (G2), OXA+5-FU; Group 3 (G3), TRAB+OXA+5-FU. Tumor width, length, and mouse body weight were measured twice a week.

RESULTS

Both treatment groups inhibited tumor growth compared to the untreated control group. The combination of TRAB, OXA and 5-FU was significantly more efficacious than OXA+5-FU and arrested tumor growth. No significant changes were observed in body-weight in any of the three groups.

CONCLUSION

TRAB, OXA and 5-FU combination has clinical potential for this and other CRC patients.

The combination of oral-recombinant methioninase and azacitidine arrests a chemotherapy-resistant osteosarcoma patient-derived orthotopic xenograft mouse model

PURPOSE

Cancers are methionine (MET) and methylation addicted, causing them to be highly sensitive to MET restriction. The present study determined the efficacy of restricting MET with oral-recombinant methioninase (o-rMETase) and the DNA methylation inhibitor, azacitidine (AZA) on a chemotherapy-resistant osteosarcoma patient-derived orthotopic xenograft (PDOX) mouse model.

METHODS

The osteosarcoma PDOX models were randomized into five treatment groups of six mice: control; doxorubicin (DOX) alone; AZA alone; o-rMETase alone; o-rMETase-AZA combination. Tumor size and body weight were measured during the 14 days of treatment.

RESULTS

We found that tumor growth was arrested only by the o-rMETase-AZA combination treatment, as tumors with this treatment exhibited tumor necrosis with degenerative change.

CONCLUSION

This study suggests that o-rMETase-AZA combination has clinical potential for patients with chemoresistant osteosarcoma.

Patient-derived orthotopic xenograft models of sarcoma

Sarcoma is a rare and recalcitrant malignancy. Although immune and novel targeted therapies have been tested on many cancer types, few sarcoma patients have had durable responses with such therapy. Doxorubicin and cisplatinum are still first-line chemotherapy after four decades. Our laboratory has established the patient-derived orthotopic xenograft (PDOX) model using surgical orthotopic implantation (SOI). Many promising results have been obtained using the sarcoma PDOX model for identifying effective approved drugs and experimental therapeutics, as well as combinations of them for individual patients. In this review, we present our laboratory's experience with PDOX models of sarcoma, and the ability of the PDOX models to identify effective approved agents, as well as experimental therapeutics.

Combination Treatment With Sorafenib and Everolimus Regresses a Doxorubicin-resistant Osteosarcoma in a PDOX Mouse Model

BACKGROUND/AIM

Osteosarcoma is a rare but recalcitrant type of bone cancer. To discover an effective therapy for osteosarcoma, we used a patient-derived orthotopic xenograft (PDOX) mouse model. A PDOX mouse model has been established for all major cancer types. Strong synergistic efficacy of sorafenib (SFN) and everolimus (EVL) has been demonstrated in several cancers. In the present study, we examined the efficacy of a SFN and EVL combination on a doxorubicin (DOX)-resistant osteosarcoma PDOX.

MATERIALS AND METHODS

The osteosarcoma PDOX models were randomly divided into five treatment groups, each containing six mice: Control; DOX; SFN; EVL; and a combination of SFN and EVL. Mice were treated for 14 days. To observe the efficacy of these treatments, tumor size and body weight were measured, and histological sections were analyzed.

RESULTS

Tumor growth regression was observed only in the mice treated with the combination of SFN-EVL. Histological analysis revealed necrosis with degenerative changes in tumors treated with a combination of SFN-EVL.

CONCLUSION

A SFN-EVL combination could be a novel effective treatment option for osteosarcoma.

Oral Recombinant Methioninase, Combined With Oral Caffeine and Injected Cisplatinum, Overcome Cisplatinum-Resistance and Regresses Patient-derived Orthotopic Xenograft Model of Osteosarcoma

BACKGROUND/AIM

Osteosarcoma is a recalcitrant neoplasm which occurs predominantly in adolescents and young adults. Recently, using a patient-derived orthotopic xenograft (PDOX) model of malignant soft-tissue sarcoma (STS), we showed that oral recombinant methioninase (o-rMETase), in combination with caffeine, was more efficacious than o-rMETase alone in inhibiting STS tumor growth. In the present report, we determined the efficacy of o-rMETase combined with oral caffeine on a cisplatinum (CDDP)-resistant osteosarcoma PDOX model.

MATERIALS AND METHODS

Osteosarcoma PDOX models were randomly divided into seven treatment groups (6 mice in each group): untreated control; CDDP alone; o-rMETase alone; o-rMETase with caffeine; CDDP plus o-rMETase; CDDP plus caffeine; and CDDP plus o-rMETase with caffeine. Tumor size and body weight were measured throughout the treatment.

RESULTS

Tumors regressed after treatment with CDDP plus o-rMETase with caffeine. Tumors treated with CDDP plus o-rMETase with caffeine also had the most necrosis.

CONCLUSION

The combination of o-rMETase and caffeine together with first-line chemotherapy was efficacious for drug-resistant osteosarcoma and has clinical potential in the treatment of this highly-resistant neoplasm.

Oral Recombinant Methioninase Overcomes Colorectal-cancer Liver Metastasis Resistance to the Combination of 5-Fluorouracil and Oxaliplatinum in a Patient-derived Orthotopic Xenograft Mouse Model

BACKGROUND/AIM

Liver metastasis in colorectal-cancer is a recalcitrant disease. To develop precision individualized therapy of this disease, we developed a patient-derived orthotopic xenograft (PDOX) model of colorectal-cancer liver metastasis. In the present report, we evaluated the efficacy of oral recombinant methioninase (o-rMETase) in combination with 5-fluorouracil (5-FU) and oxaliplatinum (OXA) on the colorectal-cancer liver metastasis PDOX mouse model.

MATERIALS AND METHODS

Colorectal-cancer liver metastasis PDOX models were randomized into three groups of seven mice. Group 1, untreated control with phosphate buffered saline (PBS); Group 2, treated with 5-FU + OXA; and Group 3, treated with 5-FU + OXA + o-rMETase.

RESULTS

The colorectal-cancer liver metastasis PDOX model was resistant to 5-FU + OXA (p=0.83 at day 15 of treatment, Group 2). In contrast, the colorectal-cancer liver metastasis PDOX model was arrested by o-rMETase combined with 5-FU + OXA (p<0.01 at day 15, Group 3). No significant body-weight differences were observed among the groups.

CONCLUSION

The combination therapy of 5-FU and OXA with o-rMETase can overcome the resistance of first line drugs for colorectal-cancer liver metastasis.

Eribulin Suppressed Cisplatinum- and Doxorubicin-resistant Recurrent Lung Metastatic Osteosarcoma in a Patient-derived Orthotopic Xenograft Mouse Model

BACKGROUND

Osteosarcoma is a recalcitrant disease treated with surgery and intensive chemotherapy as standard. The 5-year survival rate of patients with relapsed and lung metastatic osteosarcoma is as low as 20%.

MATERIALS AND METHODS

A 16-year-old patient developed left distal femoral high-grade osteosarcoma and underwent cisplatinum-based neoadjuvant chemotherapy and surgery. From the resected tumor, a patient-derived orthotopic xenograft (PDOX) model was established in the femur of nude mice. PDOX models were randomized into the following groups: untreated control, or treatment with doxorubicin (3 mg/kg, i.p., weekly for 14 days), sunitinib (40 mg/kg, oral gavage, daily for 14 days), pazopanib (100 mg/kg, oral gavage, daily for 14 days), temozolomide(25 mg/kg, oral gavage, daily for 14 days), and eribulin (1.5 mg/kg, i.p., daily for 14 days). Tumor volume and body weight were monitored twice a week.

RESULTS

The osteosarcoma PDOX was resistant to doxorubicin, sunitinib, and pazopanib. In contrast, eribulin and temozolomide arrested tumor growth.

CONCLUSION

This study demonstrated the utility of the PDOX model in allowing effective from non-effective drugs to be distinguished in a model in which the tumor was growing on the organ corresponding to that of the patient.

Oral recombinant methioninase combined with oxaliplatinum and 5-fluorouracil regressed a colon cancer growing on the peritoneal surface in a patient-derived orthotopic xenograft mouse model

The aim of this study was to determine the efficacy of oral recombinant methioninase (o-rMETase) on a model of colon cancer growing on the peritoneal surface using a patients-derived orthotopic xenograft (PDOX) nude mouse model. Forty PDOX mouse models with colon cancer growing on the peritoneum were divided into 4 groups of 10 mice each by measuring the tumor size and fluorescence intensity: untreated control; 5-fluorouracil (5-FU) (50 mg/kg, once a week for two weeks, ip) and oxaliplatinum (OXA) (6  mg/kg, once a week for two weeks, ip); o-rMETase (100 units/day, oral 14 consecutive days); combination 5-FU + OXA and o-rMETase. All treatments inhibited tumor growth compared to the untreated control. The combination of 5-FU + OXA plus o-rMETase was significantly more efficacious than the control and each drug alone and was the only treatment that caused tumor regression. The present study is the first demonstrating the efficacy of o-rMETase combination therapy on a PDOX model of peritoneal colon cancer, suggesting potential clinical development of o-rMETase in a recalcitrant cancer.

Pioglitazone, an agonist of PPARγ, reverses doxorubicin-resistance in an osteosarcoma patient-derived orthotopic xenograft model by downregulating P-glycoprotein expression

Multidrug resistance (MDR) which results in chemoresistance is a major problem in osteosarcoma. P-glycoprotein (P-gp) plays a critical role in MDR by pumping out chemotherapy agents. Peroxisome proliferator activated receptor gamma (PPARγ) is a nuclear receptor involved in cellular differentiation and proliferation. Recently, a correlation between the expression and activity of PPARγ and the expression of P-gp-associated with MDR, has been reported in several human cancers. The present study determined if pioglitazone (PIO), a PPARγ agonist, could modulate P-gp and overcome doxorubicin (DOX)-resistance in a patient-derived orthotopic xenograft (PDOX) model of osteosarcoma. P-gp mRNA expression was quantified in 143B human osteosarcoma cells treated with DOX with/without PIO. The osteosarcoma PDOX models were randomized into four treatment groups of six mice: Control; PIO alone; DOX alone; DOX and PIO combination. Tumor size and body weight were measured during the 14 days of treatment. DOX significantly induced P-gp mRNA in a dose-dependent manner in 143B cells. PIO inhibited the increase of P-gp mRNA induced by DOX treatment when co-administrated with DOX. Tumor growth was inhibited the most by the DOX-PIO combination. Tumors treated with the DOX-PIO combination also had the most tumor necrosis. This study suggests that the DOX-PIO combination could be used in the clinic for osteosarcoma patients who develop DOX-resistance.

Efficacy of oral recombinant methioninase combined with oxaliplatinum and 5-fluorouracil on primary colon cancer in a patient-derived orthotopic xenograft mouse model

The aim of this study was to determine the efficacy of oral recombinant methioninase (o-rMETase) on a colon cancer primary tumor using a patient-derived orthotopic xenograft (PDOX) nude mouse model. Forty colon cancer primary tumor PDOX mouse models were divided into 4 groups of 10 mice each (total 40 mice) by measuring the tumor size. The groups were as follows: untreated control; 5-fluorouracil (5-FU) (50 mg/kg, once a week for two weeks, N = 10 mice) and oxaliplatinum (OXA) (6 mg/kg, once a week for two weeks, N = 10 mice); o-rMETase (100 units/day, oral 14 consecutive days, N = 10 mice); combination of 5-FU + OXA and o-rMETase (N = 10 mice). All treatments inhibited tumor growth compared to the untreated control. The combination of 5-FU + OXA and o-rMETase was significantly more efficacious than other treatments. The present study demonstrates the efficacy of o-rMETase combination therapy on a PDOX colon cancer primary tumor, suggesting potential clinical development of o-rMETase in recalcitrant cancer.

A pharmacogenomic analysis using L1000CDS2 identifies BX-795 as a potential anticancer drug for primary pancreatic ductal adenocarcinoma cells

Pancreatic cancer is one of the leading causes of cancer death, mainly due to the absence of early diagnostic tool and effective therapeutic agents. To identify an effective therapeutic agent for pancreatic ductal adenocarcinoma cells (PDAC), we used 10 Gene Expression Omnibus (GEO) data sets and L1000CDS² pharmacogenetic search tool and obtained chemical "perturvants" that were predicted to reverse the abnormal gene expression changes in PDAC. Among 20 initial candidates, we measured IC₅₀ for six compounds and identified BX-795, PDK1/TBK1 inhibitor, as a therapeutic candidate. We found that BX-795 inhibits primary PDAC cell proliferation more effectively than normal cells. Following molecular analysis revealed that BX-795 down-regulates mTOR-GSK3β pathway and trigger apoptosis. Moreover, we found that BX-795 suppresses primary PDAC cell migration via downregulation of Snail and Slug. Finally, efficacy test in patient-derived xenograft model of PDAC showed BX-795 can inhibit in vivo tumor growth as efficient as gemcitabine and a combination with trametinib further suppresses tumor growth. Collectively, these results demonstrate the BX-795 as an effective therapeutic candidate for PDAC treatment.

Sorafenib and Palbociclib Combination Regresses a Cisplatinum-resistant Osteosarcoma in a PDOX Mouse Model

BACKGROUND/AIM

Recurrent osteosarcoma is a recalcitrant disease; therefore, an improved strategy is urgently needed to provide therapy. In order to develop a novel strategy for this disease, our lab has developed a patient-derived orthotopic xenograft (PDOX) mouse model for osteosarcoma. The combination of sorafenib (SFN) and palbociclib (PAL) was shown to be effective of hepatocellular carcinoma. However, whether this combination is efficacious on osteosarcoma has not been reported. The aim of this study was to determine the efficacy of the SFN and PAL combination on a cisplatinum (CDDP)-resistant osteosarcoma PDOX model.

MATERIALS AND METHODS

Osteosarcoma PDOX models were randomly divided into five treatment groups: untreated-control, CDDP, SFN, PAL and the combination of SFN and PAL.

RESULTS

Of these agents, the SFN-PAL combination significantly regressed tumor growth, and enhanced tumor necrosis with degenerative changes in the osteosarcoma PDOX.

CONCLUSION

The SFN-PAL combination is an effective treatment strategy for osteosarcoma and therefore holds promise for clinical efficacy.

Tumor-sealing Surgical Orthotopic Implantation of Human Colon Cancer in Nude Mice Induces Clinically-relevant Metastases Without Early Peritoneal Carcinomatosis

BACKGROUND

Surgical orthotopic implantation of human colon cancer tissue to the ceca of mice has been used to mimic behavior of cancer in human patients for the development of precision cancer medicine. However, with the current method of serosal surface implantation (SSI) of pieces of human colon cancer tissue, cancer cells are exposed to the peritoneum, which can artificially increase the rate of peritoneal carcinomatosis (PC) during the disease course. The objective of the present study was to introduce a tumor-sealing method (TSM) and compare it with SSI for the ability to produce clinically-relevant metastases without artificial PC.

MATERIALS AND METHODS

HCT116 colon cancer cells transfected with green fluorescence protein (GFP) were cultured and then injected into the subcutaneous layer of athymic nude mice. Subcutaneous tumors were allowed to grow sufficiently to supply adequate tumor for orthotopic implantation. For SSI, a 1 mm3-sized tumor fragment was sutured to partially torn serosa of the cecum. For TSM, the blind end of the cecum was folded over the tumor fragment and sealed with sutures. At 20 days after implantation, all mice were opened to visualize PC by intravital fluorescence imaging. At necropsy, distant metastasis was investigated using frozen section of whole blocks of organs.

RESULTS

At 20 days after implantation, PC rates in the SSI group and the TSM group were 80% (12/15) and 20% (3/15), respectively (p<0.001). The liver metastasis rate was 41.7% (5/12) in the SSI group and 50% (5/10) in the TSM group (p=0.696). The lung metastasis rate was 0% (0/12) in the SSI group and 10% (1/10) in the TSM group (p=0.201). The mean survival of mice without PC on the 20th day was significantly longer than that of mice with PC on the 20th day (69.1±14.7 vs. 44.5±12.4 days, p=0.001).

CONCLUSION

These results suggest that TSM might be a more patient-like and useful method as a model of metastatic colon cancer than SSI.

Expression of anti-aging type-XVII collagen (COL17A1/BP180) in hair follicle-associated pluripotent (HAP) stem cells during differentiation

Hair-follicle-associated pluripotent (HAP) stem cells reside in the upper part of the bulge area of the the hair follicle. HAP stem cells are nestin-positive and keratin 15-negative and have the capacity to differentiate into various types of cells in vitro. HAP stem cells are also involved in nerve and spinal cord regeneration in mouse models. Recently, it was shown that the DNA-damage response in non-HAP hair follicle stem cells induces proteolysis of type-XVII collagen (COL17A1/BP180), which is involved in hair-follicle stem-cell maintenance. COL17A1 proteolysis stimulated hair-follicle stem-cell aging, characterized by the loss of stemness signatures and hair-follicle miniaturization associated with androgenic alopecia. In the present study, we demonstrate that HAP stem cells co-express nestin and COL17A1 in vitro and in vivo. The expression of HAP stem cell markers (nestin and SSEA1) increased after HAP stem-cell colonies were formed, then decreased after differentiation to epidermal keratinocytes. In contrast COL17A1 increased after differentiation to epidermal keratinocytes. These results suggest that COL17A1 is important in differentiation of HAP stem cells.

The Combination of Olaratumab with Doxorubicin and Cisplatinum Regresses a Chemotherapy-Resistant Osteosarcoma in a Patient-Derived Orthotopic Xenograft Mouse Model

Chemotherapy-resistant osteosarcoma is a recalcitrant disease. It is a frequent cause of death to the patients who are usually adolescent or young adults. The goal of the present study was to determine the efficacy of the combination of olaratumab (OLA), doxorubicin (DOX), and cisplatinum (CDDP) on osteosarcoma, which is resistant to first-line therapy, in a patient-derived orthotopic xenograft (PDOX) model. The osteosarcoma PDOX model was randomized into six treatment groups of six mice: control; CDDP alone; DOX and CDDP; OLA + DOX; OLA + CDDP; and OLA + DOX and CDDP. Tumor size and body weight were measured during 14 days of treatment. Tumor growth was regressed only by the treatment with a combination of OLA + DOX and CDDP. Tumors treated with this three-drug combination had the most tumor necrosis and the lowest Ki-67 index. The present study demonstrates the power of the PDOX model to identify novel effective treatment strategy for chemotherapy-resistant osteosarcoma.

Peritoneal Metastases in a Patient-derived Orthotopic Xenograft (PDOX) Model of Colon Cancer Imaged Non-invasively via Red Fluorescent Protein Labeled Stromal Cells

BACKGROUND/AIM

Patient-derived orthotopic xenograft (PDOX) models have patient-like clinical features and may be imaged, in case of some cancers, by passaging of the tumors through transgenic nude mice expressing red-fluorescent protein (RFP) where they stably acquire RFP expressing stroma. The aim of the present study was to quantify red fluorescent area and intensity in colon-cancer peritoneal metastases in PDOX models in non-transgenic nude mice after passage in RFP transgenic nude mice by non-invasive external fluorescence imaging.

MATERIALS AND METHODS

Tumor fragments originating from a colon cancer patient with peritoneal metastases were implanted in transgenic RFP nude mice. Resultant tumors were harvested, and fragments were implanted in the same strain a second time. Passaged tumors stably acquired RFP-expressing stroma from their transgenic hosts. The tumor with RFP-expressing stromal cells were harvested and implanted orthotopically in non-transgenic nude mice. At eight weeks post-implantation, non-invasive external RFP images were obtained. RFP area and intensity were measured and correlated with tumor weight and volume.

RESULTS

Metastatic patient colon cancer can be stably and brightly labeled by passage in transgenic RFP-expressing nude mice such that tumor growth could be non-invasively imaged. Tumor growing could be non-invasively imaged when passaged to non-transgenic nude mice. A strong correlation between fluorescence intensity and area values with tumor weight and volume were established by external fluorescence imaging.

CONCLUSION

This new tumor model of metastatic colon cancer can be used to evaluate novel therapeutics in real time for this recalcitrant disease.

Hair-follicle-associated pluripotent stem cells derived from cryopreserved intact human hair follicles sustain multilineage differentiation potential

The bulge area of the hair follicle contains hair-follicle-associated pluripotent (HAP) stem cells. Here, we present effective cryopreservation procedures of the human hair follicle that preserve the differentiation potential of HAP stem cells. Whole hair follicles isolated from human scalp were cryopreserved by a slow-rate cooling medium and stored in liquid nitrogen. A careful thawing method was used to collect the upper parts of the human hair follicles which were cultured for four weeks in a Dulbecco’s Modified Eagle’s Medium with fetal bovine serum (FBS). Proliferating hair follicle cells were then shifted to DMEM/Ham’s Nutrient Mixture F-12 medium without FBS and allowed to grow for one week. These proliferating cells were able to produce HAP stem cell colonies with multilineage differentiation capacity. They produced keratinocytes, smooth muscle cells, cardiac muscle cells, neurons and glial cells. Interestingly, these cryopreserved hair follicles produced pluripotent HAP stem cell colonies similar to fresh follicles. These findings suggest that the cryopreserved whole human hair follicle preserves the ability to produce HAP stem cells, which will enable any individual to preserve a bank of these stem cells for personalized regenerative medicine.

The combination of gemcitabine and docetaxel arrests a doxorubicin-resistant dedifferentiated liposarcoma in a patient-derived orthotopic xenograft model

Liposarcoma (LS) is a chemotherapy-resistant disease. The aim of the present study was to find precise therapy for a recurrent dedifferentiated liposarcoma (DDLS) in a patient-derived orthotopic xenograft (PDOX) model. The DDLS PDOX models were established orthotopically in the right inguinal area of nude mice. The DDLS PDOX models were randomized into five groups: untreated; doxorubicin (DOX); gemcitabine (GEM) combined with docetaxel (DOC); pazopanib (PAZ); and yondelis (YON). On day 15, all mice were sacrificed. Measurement of tumor volume and body weight were done two times a week. The DDLS PDOX was resistant to DOX (P > 0.184). YON suppressed tumor growth significantly compared to control group (P < 0.027). However, only GEM combined with DOC arrested the tumor growth (P < 0.001). These findings suggest that GEM combined with DOC has clinical potential for this and possibly other DDLS patients.

Tumor-targeting Salmonella typhimurium A1-R overcomes nab-paclitaxel resistance in a cervical cancer PDOX mouse model

PURPOSE

Cervical cancer is a recalcitrant disease. To help overcome this problem, we previously established a patient-derived orthotopic xenograft (PDOX) model of cervical cancer. In the previous study, we found the tumor to be resistant to nab-paclitaxal (nab-PTX). We also previously developed the tumor-targeting bacteria Salmonella typhimurium A1-R (S. typhimurium A1-R). The aim of the present study was to investigate the efficacy of S. typhimurium A1-R to overcome nab-PTX resistance in the cervical cancer PDOX model.

METHODS

Cervical-cancer tumor fragments were implanted orthotopically into the neck of the uterus of nude mice. The cervical-cancer PDOX models were randomized into the following four groups after the tumor volume reached 60 mm3: G1: untreated group; G2: nab-PTX (i.v., 10 mg/kg, biweekly, 3 weeks); G3: Salmonella typhimurium A1-R (i.v., 5 × 107 CFU/body, weekly, 3 weeks); G4: nab-PTX combined with Salmonella typhimurium A1-R (nab-PTX, 10 mg/kg, i.v., biweekly, 3 weeks; S. typhimurium A1-R, 5 × 107 CFU/body, i.v., weekly, 3 weeks). Each group comprised eight mice. All mice were sacrificed on day 22. Tumor volume was measured on day 0 and day 22. Body weight was measured twice a week.

RESULTS

Nab-PTX and Salmonella typhimurium A1-R did not show significant efficacy as monotherapy compared to the control group (P = 0.564 and P = 0.120, respectively). In contrast, nab-PTX combined with Salmonella typhimurium A1-R significantly suppressed tumor growth compared to the untreated control group and nab-PTX group (P < 0.001 and P = 0.026, respectively).

CONCLUSIONS

Salmonella typhimurium A1-R has potential future clinical application to overcome drug resistance in cervical cancer.

Pazopanib regresses a doxorubicin-resistant synovial sarcoma in a patient-derived orthotopic xenograft mouse model

Synovial sarcoma (SS) is an aggressive subgroup of soft tissue sarcoma (STS) with high grade and high risk of metastasis. However, there are no systemic therapies available that target SS. Therefore, transformative therapy is needed for SS. To establish a patient-derived orthotopic xenograft (PDOX) model, a patient tumor with high grade SS from a lower extremity was grown orthotopically in the right biceps femoris muscle of mice. To test the efficacy of drugs, the PDOX models were randomized into five groups: Group 1 (G1), control-without treatment; Group 2 (G2), doxorubicin (DOX); Group 3 (G3), temozolomide (TEM); Group 4 (G4), gemcitabine (GEM) combined with docetaxel (DOC); and Group 5 (G5), pazopanib (PAZ). Tumor size and body weight were measured twice a week for each treatment group. A significant growth inhibition was found on day 14 in each treatment group compared to the untreated control, except for DOX. However, PAZ was significantly more effective than both TEM and GEM + DOC. In addition, PAZ significantly regressed the tumor volume on day 14 compared to day 0. No change was found in body weight on day 14 compared to day 0 in any treatment group. The present study demonstrated the precision of the SS PDOX models for individualizing SS therapy.

Temozolomide targets and arrests a doxorubicin-resistant follicular dendritic-cell sarcoma patient-derived orthotopic xenograft mouse model

Follicular dendritic cell sarcoma (FDCS) is a very rare and highly recalcitrant disease. A patient's doxorubicin-resistant FDCS was previously established orthotopically on the right high thigh into the biceps femoris of mice to establish a patient-derived orthotopic xenograft (PDOX) model. The aim of the present manuscript was to identify an effective drug for this recalcitrant tumor. Here, we evaluated the efficacy of temozolomide (TMZ), trabectedin (TRAB) and pazopanib (PAZ) on the FDCS PDOX model. PDOX mouse models were randomized into five groups of eight to nine mice, respectively. Group 1, untreated control with PBS, i.p.; Group 2, treated with doxorubicin (DOX), 2.4 mg/kg, i.p., weekly for 3 weeks; Group 3, treated with PAZ, 50 mg/kg, oral gavage, daily for 3 weeks; Group 4, treated with TMZ, 25 mg/kg, oral gavage, daily for 3 weeks; Group 5, treated with TRAB, 0.15 mg/kg, i.v., weekly for 3 weeks. Body weight and tumor volume were assessed 2 times per week. TMZ arrested the FDCS PDOX model compared to the control group (p < 0.05). PAZ and TRAB did not have significant efficacy compared to the control group (p = 0.99, p = 0.69 respectively). The PDOX tumor was resistant to DOX (p= 0.99). as was the patient. The present study demonstrates that TMZ is effective for a PDOX model of FDCS established from a patient who failed DOX treatment, further demonstrating the power of PDOX to identify effective therapy including for tumors that failed first line therapy.