Investigating Ras homolog gene family member C (RhoC) and Ki67 expression following external beam radiation therapy show increased RhoC expression in relapsing prostate cancer xenografts.

Ras homolog gene family member C (RhoC) is a GTPase involved in cell migration, implicated in epithelial-mesenchymal transition and treatment resistance and metastasis of cancer. For example, RhoC has been shown to be involved in resistance to radiation in cervical carcinoma. Here, the effect of X-ray irradiation on RhoC expression in prostate cancer (PCa) xenografts was investigated in both xenografts in regression and relapse. Male BALB/cAnNRj-Foxn1nu/nu mice were inoculated with 4-6 million LNCaP-FGC cells and established xenografts were irradiated with X-rays (200 kV, 1 Gymin-1), 5, 10 or 15 Gy using a Gulmay Medical X-ray system. Expression of RhoC and Ki67, a known proliferation marker, was investigated in xenografts, given 15 Gy, 7 days (midst response as measured by size) or 3 weeks (relapse) post irradiation. Staining was quantified using the Halo software (v2.3.2089.34) with the Indica Labs - cytonuclear v1.6 algorithm. RhoC and Ki67 staining was divided into weak, medium, and strong staining and the percentage of cells stained, single and dual staining, was quantified. The HALO software was further used to classify the tissue in each section so that analysis of RhoC and Ki67 expression in cancer cells, stroma and necrotic areas could be done separately. The results showed that RhoC expression in cancer and stroma cells was significantly higher in relapsed xenografts than in those in regression. This was not seen for Ki67 staining, where the percentage of stained cells were the same in regressing and relapsing tumors. RhoC could be a useful biomarker to confirm relapse following external beam radiation therapy.

KCa channel targeting impairs DNA repair and invasiveness of patient-derived glioblastoma stem cells in culture and orthotopic mouse xenografts which only in part is predictable by KCa expression levels.

Prognosis of glioblastoma patients is still poor despite multimodal therapy. The highly brain-infiltrating growth in concert with a pronounced therapy resistance particularly of mesenchymal glioblastoma stem-like cells (GSCs) has been proposed to contribute to therapy failure. Recently, we have shown that a mesenchymal-to-proneural mRNA signature of patient derived GSC-enriched (pGSC) cultures associates with in vitro radioresistance and gel invasion. Importantly, this pGSC mRNA signature is prognostic for patients' tumor recurrence pattern and overall survival. Two mesenchymal markers of the mRNA signature encode for IKCa and BKCa Ca2+-activated K+ channels. Therefore, we analyzed here the effect of IKCa- and BKCa-targeting concomitant to (fractionated) irradiation on radioresistance and glioblastoma spreading in pGSC cultures and in pGSC-derived orthotopic xenograft glioma mouse models. To this end, in vitro gel invasion, clonogenic survival, in vitro and in vivo residual DNA double strand breaks (DSBs), tumor growth, and brain invasion were assessed in the dependence on tumor irradiation and K+ channel targeting. As a result, the IKCa- and BKCa-blocker TRAM-34 and paxilline, respectively, increased number of residual DSBs and (numerically) decreased clonogenic survival in some but not in all IKCa- and BKCa-expressing pGSC cultures, respectively. In addition, BKCa- but not IKCa-blockade slowed-down gel invasion in vitro. Moreover, systemic administration of TRAM-34 or paxilline concomitant to fractionated tumor irradiation increased in the xenograft model(s) residual number of DSBs and attenuated glioblastoma brain invasion and (numerically) tumor growth. We conclude, that KCa-blockade concomitant to fractionated radiotherapy might be a promising new strategy in glioblastoma therapy.

The effects of enoxaparin treatment in a xenograft mouse model of oral squamous cell carcinoma: A pilot study.

BACKGROUND: Recent studies suggest that enoxaparin may have therapeutic effects on oral squamous cell carcinoma. We aimed to assess this effect utilizing xenograft mouse model through evaluations of proliferation and angiogenesis markers at the RNA and protein levels. METHODS: Mice were divided into enoxaparin treatment (n = 4), positive control (n = 4) and negative control (n = 3) groups. Immunohistochemical analyses were performed utilizing Bcl-2, Bax and Ki-67 antibodies. Expression levels of proliferation and apoptosis related genes were calculated utilizing qRT-PCR. Time-dependent proliferation assays were performed in OSC-19 and HEK293 cell-lines. RESULTS: Bax antibody showed positive staining in the cytoplasm and nuclei of tumor cells, while Bcl-2 antibody displayed staining only in the cytoplasm. A proliferation index of 15%-20% was found in all groups with the Ki-67 marker indicating no metastasis. Enoxaparin treatment caused decrease in BCL2, BAX and CCNB1 genes' expressions. Compared to HEK293, proliferation assays demonstrated higher division rates in OSC-19 with a significant decrease in viability after 96 h. CONCLUSION: Reduced BCL-2 expression indicates a regression of tumor growth, but reduced BAX expression is not correlated with increased apoptosis. Despite the aggressive nature of OSC-19, our results showed a low cell viability with a high division rate when compared with the control HEK293. This paralleled our in vivo findings that showed absence of lymph node metastasis across all mice groups. This discrepancy with the literature suggests that further investigations of the underlying mechanisms and protein-level analyses are needed to draw definitive conclusions about the effect of enoxaparin on OSC-19 behavior.

Analysis of SARS-CoV-2 omicron mutations that emerged during long-term replication in a lung cancer xenograft mouse model.

SARS-CoV-2 Omicron has the largest number of mutations among all the known SARS-CoV-2 variants. The presence of these mutations might explain why Omicron is more infectious and vaccines have lower efficacy to Omicron than other variants, despite lower virulence of Omicron. We recently established a long-term in vivo replication model by infecting Calu-3 xenograft tumors in immunodeficient mice with parental SARS-CoV-2 and found that various mutations occurred majorly in the spike protein during extended replication. To investigate whether there are differences in the spectrum and frequency of mutations between parental SARS-CoV-2 and Omicron, we here applied this model to Omicron. At 30 days after infection, we found that the virus was present at high titers in the tumor tissues and had developed several rare sporadic mutations, mainly in ORF1ab with additional minor spike protein mutations. Many of the mutant isolates had higher replicative activity in Calu-3 cells compared with the original SARS-CoV-2 Omicron virus, suggesting that the novel mutations contributed to increased viral replication. Serial propagation of SARS-CoV-2 Omicron in cultured Calu-3 cells resulted in several rare sporadic mutations in various viral proteins with no mutations in the spike protein. Therefore, the genome of SARS-CoV-2 Omicron seems largely stable compared with that of the parental SARS-CoV-2 during extended replication in Calu-3 cells and xenograft model. The sporadic mutations and modified growth properties observed in Omicron might explain the emergence of Omicron sublineages. However, we cannot exclude the possibility of some differences in natural infection.

Anticancer Effects of α-Pinene in AGS Gastric Cancer Cells.

Gastric cancer is the fifth most common cancer globally and the third leading cause of cancer-related mortality. Existing treatment strategies for gastric cancer often present numerous side effects. Consequently, recent studies have shifted toward devising new treatments grounded in safer natural substances. α-Pinene, a natural terpene found in the essential oils of various plants, such as Lavender angustifolia and Satureja myrtifolia, displays antioxidant, antibiotic, and anticancer properties. Yet, its impact on gastric cancer remains unexplored. This research assessed the effects of α-pinene in vitro using a human gastric adenocarcinoma cell-line (AGS) human gastric cancer cells and in vivo via a xenograft mouse model. The survival rate of AGS cells treated with α-pinene was notably lower than that of the control group, as revealed by the 3-(4,5-dimethylthiazol-2-yl)-2,5 diphenyltetrazolium bromide assay. This decline in cell viability was linked to apoptosis, as verified by 4',6-diamidino-2-phenylindole and annexin V/propidium iodide staining. The α-pinene-treated group exhibited elevated cleaved-poly (ADP-ribose) polymerase and B cell lymphoma 2 (Bcl-2)-associated X (Bax) levels and reduced Bcl-2 levels compared with the control levels. Moreover, α-pinene triggered the activation of extracellular signal-regulated kinase, c-Jun N-terminal kinase, and p38 within the mitogen-activated protein kinase (MAPK) pathway. In the xenograft mouse model, α-pinene induced apoptosis through the MAPK pathway, devoid of toxicity. These findings position α-pinene as a promising natural therapeutic for gastric cancer.

Comparative Evaluation of STEAP1 Targeting Chimeric Antigen Receptors with Different Costimulatory Domains and Spacers.

We have developed a chimeric antigen receptor (CAR) against the six-transmembrane epithelial antigen of prostate-1 (STEAP1), which is expressed in prostate cancer, Ewing sarcoma, and other malignancies. In the present study, we investigated the effect of substituting costimulatory domains and spacers in this STEAP1 CAR. We cloned four CAR constructs with either CD28 or 4-1BB costimulatory domains, combined with a CD8a-spacer (sp) or a mutated IgG-spacer. The CAR T-cells were evaluated in short- and long-term in vitro T-cell assays, measuring cytokine production, tumor cell killing, and CAR T-cell expansion and phenotype. A xenograft mouse model of prostate cancer was used for in vivo comparison. All four CAR constructs conferred CD4+ and CD8+ T cells with STEAP1-specific functionality. A CD8sp_41BBz construct and an IgGsp_CD28z construct were selected for a more extensive comparison. The IgGsp_CD28z CAR gave stronger cytokine responses and killing in overnight caspase assays. However, the 41BB-containing CAR mediated more killing (IncuCyte) over one week. Upon six repeated stimulations, the CD8sp_41BBz CAR T cells showed superior expansion and lower expression of exhaustion markers (PD1, LAG3, TIGIT, TIM3, and CD25). In vivo, both the CAR T variants had comparable anti-tumor activity, but persisting CAR T-cells in tumors were only detected for the 41BBz variant. In conclusion, the CD8sp_41BBz STEAP1 CAR T cells had superior expansion and survival in vitro and in vivo, compared to the IgGsp_CD28z counterpart, and a less exhausted phenotype upon repeated antigen exposure. Such persistence may be important for clinical efficacy.

[Retracted] Rotenone restrains colon cancer cell viability, motility and epithelial­mesenchymal transition and tumorigenesis in nude mice via the PI3K/AKT pathway.

Following the publication of this paper, it was drawn to the Editor's attention by a concerned reader that the immunofluorescence staining data shown in Fig. 3C, and the migration and invasion assay data shown in Figs. 4C and 4D were strikingly similar to data appearing in different form in other research articles written by different authors at different research institutes that had either already been published, or were submitted for publication at around the same time, one of which has been retracted. In addition, the western blotting data shown for the E­cadherin and AKT protein bands in Fig. 5 were strikingly similar, albeit the bands had been flipped vertically. Owing to the fact that contentious data in the above article had already been submitted for publication elsewhere prior to its submission to International Journal of Molecular Medicine, the Editor has decided that this paper should be retracted from the Journal. The authors were asked for an explanation to account for these concerns, but the Editorial Office did not receive a reply. The Editor apologizes to the readership for any inconvenience caused. [International Journal of Molecular Medicine 44: 700­708, 2020; DOI: 10.3892/ijmm.2020.4637].

Exploring the In Vitro and In Vivo Therapeutic Potential of BRAF and MEK Inhibitor Combination in NRAS-Mutated Melanoma.

INTRODUCTION: Patients with NRAS-mutant metastatic melanoma often have an aggressive disease requiring a fast-acting, effective therapy. The MEK inhibitor binimetinib shows an overall response rate of 15% in patients with NRAS-mutant melanoma, providing a backbone for combination strategies. Our previous studies demonstrated that in NRAS-mutant melanoma, the antitumor activity of the MEK inhibitor binimetinib was significantly potentiated by the BRAFV600E/K inhibitor encorafenib through the induction of ER stress, leading to melanoma cell death by apoptotic mechanisms. Encorafenib combined with binimetinib was well tolerated in a phase III trial showing potent antitumor activity in BRAF-mutant melanoma, making a rapid evaluation in NRAS-mutant melanoma imminently feasible. These data provide a mechanistic rationale for the evaluation of binimetinib combined with encorafenib in preclinical and clinical studies on NRAS-mutant metastatic melanoma. METHODS: The combination of BRAFi plus MEKi was tested in a monolayer culture of patient-derived cell lines and in corresponding patient-derived tissue slice cultures of NRAS-mutant melanoma. To investigate the treatment in vivo, NSG (NOD. Cg-PrkdcscidIl2rgtm1Wjl/SzJ) mice were subcutaneously injected with three different BRAF wild-type melanoma models harboring oncogenic NRAS mutations and treated orally with encorafenib (6 mg/kg body weight, daily) with or without binimetinib (8 mg/kg body weight, twice daily). In parallel, an individual healing attempt was carried out by treating one patient with an NRAS-mutated tumor. RESULTS: Encorafenib was able to enhance the inhibitory effect on cell growth of binimetinib only in the cell line SKMel147 in vitro. It failed to enhance the apoptotic effect found in two other NRAS-mutated cell lines. Encorafenib led to a hyperactivation of ERK which could be reduced with the combinational treatment. In two of the three patient-derived tissue slice culture models of NRAS-mutant melanomas, a slight tendency of a combinatorial effect was seen which was not significant. Encorafenib showed a slight induction of the ER stress genes ATF4, CHOP, and NUPR1. The combinational treatment was able to enhance this effect, but not significantly. In the mouse model, the combination therapy of encorafenib with binimetinib resulted in reduced tumor growth compared to the control and encorafenib groups; however, the best effect in terms of tumor growth inhibition was measured in the binimetinib therapy group. The therapy showed no effect in an individual healing attempt for a patient suffering from metastatic, therapy-refractory NRAS-mutated melanoma. CONCLUSION: In in vitro and ex vivo settings, the combination therapy was observed to elicit a response; however, it did not amplify the efficacy observed with binimetinib alone, whereas in a patient, the combinational treatment remained ineffective. The preclinical in vivo data showed no increased combinatorial effect. However, the in vivo effect of binimetinib as monotherapy was unexpectedly high in the tested regimen. Nevertheless, binimetinib proved to be advantageous in the treatment of melanoma in vivo and led to high rates of apoptosis in vitro; hence, it still seems to be a good base for combination with other substances in the treatment of patients with NRAS-mutant melanoma.

Neutralization of p40 Homodimer and p40 Monomer Leads to Tumor Regression in Patient-Derived Xenograft Mice with Pancreatic Cancer.

Pancreatic cancer is a highly aggressive cancer with a high mortality rate and limited treatment options. It is the fourth leading cause of cancer in the US, and mortality is rising rapidly, with a 12% relative 5-year survival rate. Early diagnosis remains a challenge due to vague symptoms, lack of specific biomarkers, and rapid tumor progression. Interleukin-12 (IL-12) is a central cytokine that regulates innate (natural killer cells) and adaptive (cytokine T-lymphocytes) immunity in cancer. We demonstrated that serum levels of IL-12p40 homodimer (p402) and p40 monomer (p40) were elevated and that of IL-12 and IL-23 were lowered in pancreatic cancer patients compared to healthy controls. Comparably, human PDAC cells produced greater levels of p402 and p40 and lower levels of IL-12 and IL-23 compared to normal pancreatic cells. Notably, neutralization of p402 by mAb a3-1d and p40 by mAb a3-3a induced the death of human PDAC cells, but not normal human pancreatic cells. Furthermore, we demonstrated that treatment of PDX mice with p402 mAb and p40 mAb resulted in apoptosis and tumor shrinkage. This study illustrates a new role of p402 and p40 monomer in pancreatic cancer, highlighting possible approaches against this deadly form of cancer with p402 and p40 monomer immunotherapies.

Sulforaphene suppresses oesophageal cancer growth through mitogen- and stress-activated kinase 2 in a PDX mouse model.

BACKGROUND: Although sulforaphene has potential anticancer effects, little is known about its effect on oesophageal squamous cell carcinoma (ESCC) invasiveness. METHODS: To investigate whether sulforaphene inhibits the growth of oesophageal cancer cells, MTT and anchorage-independent cell growth assays were performed. Global changes in the proteome and phosphoproteome of oesophageal cancer cells after sulforaphene treatment were analysed by mass spectrometry (MS), and the underlying molecular mechanism was further verified by in vivo and in vitro experiments. RESULTS: Sulforaphene treatment markedly affected proteins that regulate several cellular processes in oesophageal cancer cells, and mitogen- and stress-activated kinase 2 (MSK2) was the main genetic target of sulforaphene in reducing the growth of oesophageal cancer cells. Sulforaphene significantly suppressed ESCC cell proliferation in vitro and reduced the tumour size in an oesophageal patient-derived xenograft (PDX) SCID mouse model. Furthermore, the binding of sulforaphane to MSK2 in vitro was verified using a cellular thermal dhift assay, and the effect of MSK2 knockdown on the ESCC phenotype was observed using a shMSK2 model. CONCLUSION: The results showed that sulforaphene suppresses ESCC growth in both human oesophageal squamous cells and PDX mouse model by inhibiting MSK2 expression, implicating sulforaphene as a promising candidate for ESCC treatment.

Mobilization of Circulating Tumor Cells after Short- and Long-Term FOLFIRINOX and GEM/nab-PTX Chemotherapy in Xenograft Mouse Models of Human Pancreatic Cancer.

Mobilization of CTCs after various types of therapy, such as radiation therapy, has been reported, but systematic study of CTCs after chemotherapy remained quite limited. In this study, we sequentially examined CTC numbers after single-dose and repetitive-dose chemotherapy, including FORFIRINOX (FFX) and Gemcitabine and nab-Paclitaxel (GnP) using two pancreatic cancer xenograft models. CTC was detected by the immunocytology-based microfluidic platform. We further examined the dynamic change in the histology of primary tumor tissues during chemotherapy. We confirmed a transient increase in CTCs 1-2 weeks after single-dose and repetitive-dose of FFX/GnP chemotherapy. Histological examination of the primary tumors revealed that the peak period of CTC at 1-2 weeks after chemotherapy corresponded to the maximal destructive phase consisting of cell cycle arrest, apoptosis of tumor cells, and blood vessel destruction without secondary reparative tissue reactions and regeneration of tumor cells. These findings indicate that mobilization of CTCs early after chemotherapy is mediated by the shedding of degenerated tumor cells into the disrupted blood vessels driven by the pure destructive histological changes in primary tumor tissues. These results suggest that sequential CTC monitoring during chemotherapy can be a useful liquid biopsy diagnostic tool to predict tumor chemosensitivity and resistance in preclinical and clinical settings.

Zwitterionic polymer on silicone implants inhibits the bacteria-driven pathogenic mechanism and progress of breast implant-associated anaplastic large cell lymphoma.

Breast implant-associated anaplastic large cell lymphoma (BIA-ALCL) occurs in the capsule surrounding breast implants. Malignant transformation of T cells by bacteria-driven chronic inflammation may be underlying BIA-ALCL mechanism. Here, we covalently grafted 2-methacryloyloxyethyl phosphorylcholine (MPC)-based polymers on a silicone surface and examined its effects against BIA-ALCL pathogenesis. MPC grafting strongly inhibited the adhesion of bacteria and bacteria-causing inflammation. Additionally, cancer T cell proliferation and capsule-derived fibroblast-cancer cell communication were effectively inhibited by MPC grafting. We further demonstrated the effect of MPC against the immune responses causing BIA-ALCL around human silicone implants in micro-pigs. Finally, we generated a xenograft anaplastic T cell lymphoma mouse model around the silicone implants and demonstrated that MPC grafting could effectively inhibit the lymphoma progression. This study is the first to show that bacteria-driven induction and progression of BIA-ALCL can be effectively inhibited by surface modification of implants. STATEMENT OF SIGNIFICANCE: Breast implant-associated anaplastic large cell lymphoma (BIA-ALCL) is a major concern in the field of plastic and reconstructive surgery. In this study, we demonstrate strong inhibitory effect of zwitterionic polymer grafting on BIA-ALCL pathogenesis and progression, induced by bacterial infection and inflammation, both in vitro and in vivo. This study provides a molecular basis for the development of novel breast implants that can prevent various potential complications such as excessive capsular contracture, breast implant illness, and BIA-ALCL incidence, as well as for expanding the biomedical applications of zwitterionic polymers.

TP5: A Novel Therapeutic Approach Targeting Aberrant and Hyperactive CDK5/p25 for the Treatment of Colorectal Carcinoma.

Colorectal carcinoma (CRC) is a prevalent cancer worldwide with a high mortality rate. Evidence suggests that increased expression of Cyclin-dependent kinase 5 (CDK5) contributes to cancer progression, making it a promising target for treatment. This study examined the efficacy of selectively inhibiting CDK5 in colorectal carcinoma using TP5, a small peptide that selectively inhibits the aberrant and hyperactive CDK5/p25 complex while preserving physiological CDK5/p35 functions. We analyzed TP5's impact on CDK5 activity, cell survival, apoptosis, the cell cycle, DNA damage, ATM phosphorylation, and reactive oxygen species (ROS) signaling in mitochondria, in CRC cell lines, both alone and in combination with chemotherapy. We also assessed TP5's efficacy on a xenograft mouse model with HCT116 cells. Our results showed that TP5 decreased CDK5 activity, impaired cell viability and colony formation, induced apoptosis, increased DNA damage, and led to the G1 phase arrest of cell cycle progression. In combination with irinotecan, TP5 demonstrated a synergy by leading to the accumulation of DNA damage, increasing the γH2A.X foci number, and inhibiting G2/M arrest induced by Sn38 treatment. TP5 alone or in combination with irinotecan increased mitochondrial ROS levels and inhibited tumor growth, prolonging mouse survival in the CRC xenograft animal model. These results suggest that TP5, either alone or in combination with irinotecan, is a promising therapeutic option for colorectal carcinoma.

Chrysomycin A Regulates Proliferation and Apoptosis of Neuroglioma Cells via the Akt/GSK-3ß Signaling Pathway In Vivo and In Vitro.

Glioblastoma (GBM) is a major type of primary brain tumor without ideal prognosis and it is therefore necessary to develop a novel compound possessing therapeutic effects. Chrysomycin A (Chr-A) has been reported to inhibit the proliferation, migration and invasion of U251 and U87-MG cells through the Akt/GSK-3ß signaling pathway, but the mechanism of Chr-A against glioblastoma in vivo and whether Chr-A modulates the apoptosis of neuroglioma cells is unclear. The present study aims to elucidate the potential of Chr-A against glioblastoma in vivo and how Chr-A modulates the apoptosis of neuroglioma cells. Briefly, the anti-glioblastoma activity was assessed in human glioma U87 xenografted hairless mice. Chr-A-related targets were identified via RNA-sequencing. Apoptotic ratio and caspase 3/7 activity of U251 and U87-MG cells were assayed via flow cytometry. Apoptosis-related proteins and possible molecular mechanisms were validated via Western blotting. The results showed that Chr-A treatment significantly inhibits glioblastoma progression in xenografted hairless mice, and enrichment analysis suggested that apoptosis, PI3K-Akt and Wnt signaling pathways were involved in the possible mechanisms. Chr-A increased the apoptotic ratio and the activity of caspase 3/7 in U251 and U87-MG cells. Western blotting revealed that Chr-A disturbed the balance between Bax and Bcl-2, activating a caspase cascade reaction and downregulating the expression of p-Akt and p-GSK-3ß, suggesting that Chr-A may contribute to glioblastoma regression modulating in the Akt/GSK-3ß signaling pathway to promote apoptosis of neuroglioma cells in vivo and in vitro. Therefore, Chr-A may hold therapeutic promise for glioblastoma.

Tumor Growth Suppression of Pancreatic Cancer Orthotopic Xenograft Model by CEA-Targeting CAR-T Cells.

Chimeric antigen receptor engineered T cell (CAR-T) therapy has high therapeutic efficacy against blood cancers, but it has not shown satisfactory results in solid tumors. Therefore, we examined the therapeutic effect of CAR-T therapy targeting carcinoembryonic antigen (CEA) in pancreatic adenocarcinoma (PDAC). CEA expression levels on the cell membranes of various PDAC cell lines were evaluated using flow cytometry and the cells were divided into high, medium, and low expression groups. The relationship between CEA expression level and the antitumor effect of anti-CEA-CAR-T was evaluated using a functional assay for various PDAC cell lines; a significant correlation was observed between CEA expression level and the antitumor effect. We created orthotopic PDAC xenograft mouse models and injected with anti-CEA-CAR-T; only the cell line with high CEA expression exhibited a significant therapeutic effect. Thus, the therapeutic effect of CAR-T therapy was related to the target antigen expression level, and the further retrospective analysis of pathological findings from PDAC patients showed a correlation between the intensity of CEA immunostaining and tumor heterogeneity. Therefore, CEA expression levels in biopsies or surgical specimens can be clinically used as biomarkers to select PDAC patients for anti-CAR-T therapy.

Treatment with Anti-HER2 Chimeric Antigen Receptor Tumor-Infiltrating Lymphocytes (CAR-TILs) Is Safe and Associated with Antitumor Efficacy in Mice and Companion Dogs.

Patients with metastatic melanoma have a historically poor prognosis, but recent advances in treatment options, including targeted therapy and immunotherapy, have drastically improved the outcomes for some of these patients. However, not all patients respond to available treatments, and around 50% of patients with metastatic cutaneous melanoma and almost all patients with metastases of uveal melanoma die of their disease. Thus, there is a need for novel treatment strategies for patients with melanoma that do not benefit from the available therapies. Chimeric antigen receptor-expressing T (CAR-T) cells are largely unexplored in melanoma. Traditionally, CAR-T cells have been produced by transducing blood-derived T cells with a virus expressing CAR. However, tumor-infiltrating lymphocytes (TILs) can also be engineered to express CAR, and such CAR-TILs could be dual-targeting. To this end, tumor samples and autologous TILs from metastasized human uveal and cutaneous melanoma were expanded in vitro and transduced with a lentiviral vector encoding an anti-HER2 CAR construct. When infused into patient-derived xenograft (PDX) mouse models carrying autologous tumors, CAR-TILs were able to eradicate melanoma, even in the absence of antigen presentation by HLA. To advance this concept to the clinic and assess its safety in an immune-competent and human-patient-like setting, we treated four companion dogs with autologous anti-HER2 CAR-TILs. We found that these cells were tolerable and showed signs of anti-tumor activity. Taken together, CAR-TIL therapy is a promising avenue for broadening the tumor-targeting capacity of TILs in patients with checkpoint immunotherapy-resistant melanoma.

Dalpiciclib partially abrogates ER signaling activation induced by pyrotinib in HER2+HR+ breast cancer.

Recent evidences from clinical trials (NCT04486911) revealed that the combination of pyrotinib, letrozole, and dalpiciclib exerted optimistic therapeutic effect in treating HER2+HR+ breast cancer; however, the underlying molecular mechanism remained elusive. Through the drug sensitivity test, the drug combination efficacy of pyrotinib, tamoxifen, and dalpiciclib to BT474 cells was tested. The underlying molecular mechanisms were investigated using immunofluorescence, Western blot analysis, immunohistochemical staining, and cell cycle analysis. Potential risk factor that may indicate the responsiveness to drug treatment in HER2+/HR+ breast cancer was identified using RNA-sequence and evaluated using immunohistochemical staining and in vivo drug susceptibility test. We found that pyrotinib combined with dalpiciclib exerted better cytotoxic efficacy than pyrotinib combined with tamoxifen in BT474 cells. Degradation of HER2 could enhance ER nuclear transportation, activating ER signaling pathway in BT474 cells, whereas dalpiciclib could partially abrogate this process. This may be the underlying mechanism by which combination of pyrotinib, tamoxifen, and dalpiciclib exerted best cytotoxic effect. Furthermore, CALML5 was revealed to be a risk factor in the treatment of HER2+/HR+ breast cancer and the usage of dalpiciclib might overcome the drug resistance to pyrotinib + tamoxifen due to CALML5 expression. Our study provided evidence that the usage of dalpiciclib in the treatment of HER2+/HR+ breast cancer could partially abrogate the estrogen signaling pathway activation caused by anti-HER2 therapy and revealed that CALML5 could serve as a risk factor in the treatment of HER2+/HR+ breast cancer.

BR101801 enhances the radiosensitivity of p53-deficient colorectal cancer cells by inducing G2/M arrest, apoptosis, and senescence in a p53-independent manner.

Inhibition of DNA-dependent protein kinase (DNA-PK) in the non-homologous end-joining repair pathway reportedly increases the radiation sensitivity of cancer cells. We have recently reported that BR101801, a novel triple inhibitor of PI3K-gamma (γ), delta (δ), and DNA-PK, functions as an efficient sensitizer of radiation-induced DNA damage in various human solid cancer cells and a xenograft mouse model. Given that the p53 tumor suppressor gene plays an important role in radiotherapeutic efficacy, in the current study, we focused on the impact of the p53 status on BR101801-induced radiosensitization using isogenic HCT116 p53+/+ and HCT116 p53-/- human colorectal cancer cell lines. In vitro, HCT116 p53+/+ and HCT116 p53-/- human colorectal cancer cells were pretreated with 1 µM BR101801 for 24 h before exposure to ionizing radiation (IR), followed by assays to analyze colony formation, DNA damage, cell cycle changes, senescence, autophagy, apoptosis, and DNA damage response-related proteins. Xenograft mouse models were constructed to examine the potential synergistic effects of BR101801 (50 mg/kg, orally administered once daily) and fractionated IR (2 Gy × 3 days) on tumor growth inhibition in vivo. BR101801 inhibited cell proliferation and prolonged DNA damage in both HCT116 p53+/+ and HCT116 p53-/- human colorectal cancer cells. Combined treatment with BR101801 and IR robustly induced G2/M phase cell cycle arrest, apoptosis, and cellular senescence in HCT116 p53-/- cells when compared with treatment with IR alone. Furthermore, BR101801 synergistically inhibited tumor growth in the HCT116 p53-/- xenograft mouse model. BR101801 enhanced the radiosensitivity of HCT116 human colorectal cancer cells regardless of their p53 status. Moreover, BR101801 exerted robust synergistic effects on IR-induced cell cycle arrest, apoptosis, and tumor growth inhibition, even in radioresistant HCT116 p53-/- cells. Overall, these findings provide a scientific rationale for combining BR101801 with IR as a new therapeutic strategy to overcome radioresistance induced by p53 deficiency.

Establishment of head and neck squamous cell carcinoma mouse models for cetuximab resistance and sensitivity.

Aim: Acquired resistance to the targeted agent cetuximab poses a significant challenge in finding effective anti-cancer treatments for head and neck squamous cell carcinoma (HNSCC). To accurately study novel combination treatments, suitable preclinical mouse models for cetuximab resistance are key yet currently limited. This study aimed to optimize an acquired cetuximab-resistant mouse model, with preservation of the innate immunity, ensuring intact antibody-dependent cellular cytotoxicity (ADCC) functionality. Methods: Cetuximab-sensitive and acquired-resistant HNSCC cell lines, generated in vitro, were subcutaneously engrafted in Rag2 knock-out (KO), BALB/c Nude and CB17 Scid mice with/without Matrigel or Geltrex. Once tumor growth was established, mice were intraperitoneally injected twice a week with cetuximab for a maximum of 3 weeks. In addition, immunohistochemistry was used to evaluate the tumor and its microenvironment. Results: Despite several adjustments in cell number, cell lines and the addition of Matrigel, Rag2 KO and BALB/C Nude mice proved to be unsuitable for xenografting our HNSCC cell lines. Durable tumor growth of resistant SC263-R cells could be induced in CB17 Scid mice. However, these cells had lost their resistance phenotype in vivo. Immunohistochemistry revealed a high infiltration of macrophages in cetuximab-treated SC263-R tumors. FaDu-S and FaDu-R cells successfully engrafted into CB17 Scid mice and maintained their sensitivity/resistance to cetuximab. Conclusion: We have established in vivo HNSCC mouse models with intact ADCC functionality for cetuximab resistance and sensitivity using the FaDu-R and FaDu-S cell lines, respectively. These models serve as valuable tools for investigating cetuximab resistance mechanisms and exploring novel drug combination strategies.

Policosanol suppresses tumor progression in a gastric cancer xenograft model.

Gastric cancer (GC) is the most common cancer worldwide and the third leading cause of cancer death, with the fifth highest incidence. The development of effective chemotherapeutic agents is needed to decrease GC mortality. Policosanol (PC) extracted from Cuban sugar cane wax is a healthy functional food ingredient that helps improve blood cholesterol levels and blood pressure. Its various physiological activities, such as antioxidant, anti-inflammatory, and anticancer activities, have been reported recently. Nevertheless, the therapeutic efficacy of PC in gastric xenograft models is unclear. We aimed to investigate the anticancer effect of PC on human GC SNU-16 cells and a xenograft mouse model. PC significantly inhibited GC cell viability and delayed tumor growth without toxicity in the SNU-16-derived xenograft model. Therefore, we investigated protein expression levels in tumor tissues; the expression levels of Ki-67, a proliferation marker, and cdc2 were decreased. In addition, we performed proteomic analysis and found thirteen differentially expressed proteins. Our results suggested that PC inhibited GC progression via cdc2 suppression and extracellular matrix protein regulation. Notably, our findings might contribute to the development of novel and effective therapeutic strategies for GC.