Unraveling the impact of cancer-associated fibroblasts on hypovascular pancreatic neuroendocrine tumors

BACKGROUND

Pancreatic neuroendocrine tumors (PNETs) with low microvessel density and fibrosis often exhibit clinical aggressiveness. Given the contribution of cancer-associated fibroblasts (CAFs) to the hypovascular fibrotic stroma in pancreatic ductal adenocarcinoma, investigating whether CAFs play a similar role in PNETs becomes imperative. In this study, we investigated the involvement of CAFs in PNETs and their effects on clinical outcomes.

METHODS

We examined 79 clinical PNET specimens to evaluate the number and spatial distribution of α-smooth muscle actin (SMA)-positive cells, which are indicative of CAFs. Then, the findings were correlated with clinical outcomes. In vitro and in vivo experiments were conducted to assess the effects of CAFs (isolated from clinical specimens) on PNET metastasis and growth. Additionally, the role of the stromal-cell-derived factor 1 (SDF1)-AGR2 axis in mediating communication between CAFs and PNET cells was investigated.

RESULTS

αSMA-positive and platelet-derived growth factor-α-positive CAFs were detected in the hypovascular stroma of PNET specimens. A higher abundance of α-SMA-positive CAFs within the PNET stroma was significantly associated with a higher level of clinical aggressiveness. Notably, conditioned medium from PNET cells induced an inflammatory phenotype in isolated CAFs. These CAFs promoted PNET growth and metastasis. Mechanistically, PNET cells secreted interleukin-1, which induced the secretion of SDF1 from CAFs. This cascade subsequently elevated AGR2 expression in PNETs, thereby promoting tumor growth and metastasis. The downregulation of AGR2 in PNET cells effectively suppressed the CAF-mediated promotion of PNET growth and metastasis.

CONCLUSION

CAFs drive the growth and metastasis of aggressive PNETs. The CXCR4-SDF1 axis may be a target for antistromal therapy in the treatment of PNET. This study clarifies mechanisms underlying PNET aggressiveness and may guide future therapeutic interventions targeting the tumor microenvironment.

The Utility of SOX2 and AGR2 Biomarkers as Early Predictors of Tamoxifen Resistance in ER-Positive Breast Cancer Patients

BACKGROUND

Despite the undeniable benefit of tamoxifen therapy for ER-positive breast cancer patients, approximately one-third of those patients either do not respond to tamoxifen or develop resistance. Thus, it is a crucial step to identify novel, reliable, and easily detectable biomarkers indicating resistance to this drug.

OBJECTIVE

The aim of this work is to explore SOX2 and AGR2 biomarker expression in the tumor tissue of ER-positive breast cancer patients in combination with the evaluation of serum AGR2 level of these patients in order to validate these biomarkers as early predictors of tamoxifen resistance.

METHODS

This study was conducted on 224 ER-positive breast cancer patients. All patients were primarily subjected to serum AGR2 levelling by ELISA and their breast cancer tissue immunostained for SOX2 and AGR2. After 5 years of follow-up, the patients were divided into 3 groups: group 1 was tamoxifen sensitive and groups 2 and 3 were tamoxifen resistant. Time to failure of tamoxifen treatment was considered the time from the beginning of tamoxifen therapy to the time of discovery of breast cancer recurrence or metastases (in months).

RESULTS

SOX2 and AGR2 biomarkers expression and serum AGR2 level were significantly higher in groups 2 and 3 in comparison to group 1, while the relationship between Her2 neu expression and Ki67 index in the 3 different groups was statistically nonsignificant. Lower SOX2 and AGR2 expression and low AGR2 serum levels in the studied patients of groups 2 and 3 were significantly associated with longer time-to-failure of tamoxifen treatment. According to the ROC curve, the combined use of studied markers validity was with a sensitivity of 100%, specificity of 96%, PPV 96%, and NPV 100% (p < 0.001; AUC: 0.984).

CONCLUSIONS

Integrated use of SOX2 and AGR2 biomarkers with serum AGR2 assay holds a promising hope for their future use as predictive markers for early detection of tamoxifen resistance in ER-positive breast cancer patients.

Production and application of bacteriophage and bacteriophage-encoded lysins

The widespread resistance to antibiotics among pathogenic bacteria has made development of alternatives to antibiotics a pressing public concern. Extensive studies have established bacteriophages (phages) and phage-encoded lytic enzymes (virolysins) as two of the most promising families of alternative antibacterials for the treatment and prophylaxis of bacterial infections. They have shown great potential in veterinary and human medicine for the treatment and prophylaxis of infections. Technologies have also been patented employing phages and virolysins in other pathogen related applications including detection and decontamination.

The anti-tumoral activity of human glycoprotein HGP.92: a study with the mouse Lewis-lung-tumor cell

The ability of a purified human glycoprotein (HGP.92) to exert anti-tumor activity was investigated in a mouse model using long-term readout assays. In vitro, in the presence of inflammatory mouse macrophages incubated with HGP.92, the growth of the mouse Lewis-lung-tumor cells (3LL) was decreased. This effect was concentration-dependent and required direct contact between tumor targets and HGP.92-treated macrophages. In addition, if the macrophage monolayer was depleted of HGP.92 before addition of the target cells, no more cytostatic effect was observed. This anti-tumor activity of HGP.92-treated mouse macrophage was partially abrogated by addition of catalase in the culture medium, but not by superoxide dismutase or scavengers of the hydroxyl radical and singlet oxygen. Moreover, this tumor-cell growth reduction was not dependent on nitric oxide. In vivo, multiple i.v. injections of HGP.92 (5 times, 3 days apart) during the first week and a half exerted significant anti-tumor activity, as assessed by the reduction of both the number and the size of the lung nodules 3 weeks after i.v. inoculation of 3LL cells.

Effect of Nocardia rubra cell-wall skeleton on cancer prevention in humans

The retired workers at the chemical weapons plant in Japan are regarded as a high-risk group for cancers. Under the Cancer Preventive Program, Nocardia rubra cell-wall skeleton (N-CWS) was administered to 80 workers directly involved in the production of sulfur mustard and 66 workers engaged in work related to sulfur mustard production. Untreated workers whose age, sex, duties and duration of work at this factory were individually matched to the N-CWS-treated workers were used as controls. During a 4.5-year observation period, development of cancers was found in 7 treated workers and 17 untreated controls. After elimination of the influence of the difference in smoking level, the incidence of subjects who developed cancers was compared statistically between the N-CWS-treated workers and the untreated controls and a significant suppression of development of cancers was noted in the N-CWS-treated workers. Thus, it was concluded that the administration of N-CWS could prevent cancer development in humans.

Active-specific immunotherapy for melanoma

Twenty-five patients with metastatic melanoma were treated with a therapeutic vaccine ("theraccine") consisting of allogeneic melanoma lysates and a novel adjuvant, DETOX (Ribi ImmunoChem Research, Inc, Hamilton, MT). Each patient received 200 antigenic units (20 x 10(6) tumor cell equivalents) subcutaneously on weeks 1, 2, 3, 4, and 6. Clinical responses included one complete remission, three partial remissions, and a long-term (17-month) stability. Two other patients had mixed responses, with partial remissions of numerous subcutaneous nodules. Sites of responsive disease included primarily the skin, but ileal, breast, and a liver metastasis also responded. Removal of residual lesions in patients with partial remissions, whose other lesions had disappeared during treatment, led to long disease-free survivals. The median duration of remission was 17 months, with four of the five responders alive for at least 24 months after treatment. An increase in precursors of cytolytic T cells (CTLs) correlated with clinical outcome, when complete, partial, and mixed responses and long-term stability were considered. The CTLs recognized melanoma-associated antigens on many cell lines, but not other types of tumor or normal lymphocytes. Skin-test reactivity to melanoma antigens and serum antibodies against the melanoma cells was unrelated to clinical response. Toxicity was minimal, restricted largely to minor soreness at the site of injection. Only five patients, four of whom were treated with repeated courses, developed severe granulomas. These results confirm that active-specific immunization with allogeneic lysates of melanoma administered with the adjuvant DETOX can induce immunity to melanoma, and can induce regressions of disease in a proportion of patients with metastatic disease with little toxicity.

Current status of melanoma treatment with interferon, cytokines and other biologic response modifiers in Japan

This paper introduces the current status of melanoma treatment with various biologic response modifiers (BRMs) in Japan, with an emphasis on the clinical results of Interferon therapies. The authors also refer briefly to the current situation of interleukin-2 (IL-2) and tumor necrosis factor (TNF) in Japan. Many BRMs have been used in treatment of melanoma, e.g., IFN, IL-2, TNFs, BCG, MY-1 (DNA extracted from BCG), WPG (CWs of Bifidobacterium infantis, ATCC 15697), OK-432 (Picibanil, Streptococcus pyogenes preparation), bestatin, and forphenicinol. Some of these have completed clinical trials, while others are still undergoing clinical testing. Among IFN-alpha, beta, and gamma, intralesional administration of natural IFN-beta was found to be more effective than IFN-alpha for metastatic skin melanoma, the survival time of patients being prolonged by the administration of IFN-beta. IFN-gamma appeared to have lower efficacy than IFN-alpha and beta. The frequency of BRM application to melanoma treatment will increase. The authors foresee that combinations with radio- and/or other chemotherapy will be more common than the single use of a BRM, especially in the case of IFN.

[BRM in the treatment of cancer]

Biological response modifiers can be divided into 2 groups; 1) immunomodulator (IM) or immunostimulator (IS) and 2) cytokines. Several IM or IS have been used clinically for the treatment of various cancers in combination with various chemotherapeutic agents. They are effective for prolonging the survival time or remission duration of cancer patients. However, no direct effect on cancer of the IM.IS has been proven. Cytokines such as interferons (IFNs) or interleukin-2 (IL-2) are effective against renal cell carcinoma, melanoma, hairy cell leukemia, multiple myeloma and other tumors even when they are used singly. IM.IS exert their anti-cancer effects through a combination of NK cell and macrophage activation or production of IFNs and ILs. Therefore, each effect is not strong enough to show a direct anticancer effect. Cytokines which are produced by recombinant techniques can be used in large doses and have been shown to have direct effects on certain types of cancers. The future approach is to devise the best combination between cytokines, cytokines and IM.IS, and cytokines and chemotherapeutic agents.

[Host mediated anti-tumor effect of Nocardia rubra cell wall skeleton on syngeneic tumor in mice]

The mode of action of Nocardia rubra cell wall skeleton (N-CWS) on Meth A fibrosarcoma (Meth A) was studied in BALB/c mice. N-CWS suppressed or regressed the intradermal growth of syngeneic Meth A cells in normal BALB/c and athymic BALB/c mice. The intradermally and subcutaneously infiltrated cells harvested from injection sites of N-CWS in normal mice showed in vitro cytotoxic activity against Meth A cells. Pretreatment of normal BALB/c mice with immunosuppressing agents such as hydrocortisone, carrageenan, or silica particles significantly reduced the anti-tumor effect of N-CWS. The growth of Meth A cells, rechallenged into BALB/c mice in which Meth A cells had once been suppressed or regressed by N-CWS treatment, was also inhibited, but not in similarly treated athymic nude mice. This resistant mechanism was shown to be dependent out cellular components but not on humoral components by the Winn Assay. The present results suggest that N-CWS exerts its anti-tumor activity by mediation of the immune system of the host and that the main effector cells in the early stage of tumor rejection are macrophages; T cells may also be involved in the later stage.

[Differences in the immunostimulatory activity and antitumor therapeutic effect of OK-432 and N-CWS]

Immunobiological activities of OK-432 and N-CWS were studied in BALB/c-Meth-A and C3H-MH 134 systems. Peritoneal exudate cells obtained from mice injected i.p. with OK-432 or N-CWS showed stronger in vitro cytotoxicity against Meth-A and YAC-1 cells than did those from non-treated mice. Spleen cells from OK-432 or N-CWS-treated mice exhibited lower Con A mitogenic response in comparison with those from non-treated mice. When Meth-A or MH-134 tumor cells were admixed with OK-432 or N-CWS, the intradermally inoculated tumor cells showed no or slower growth than did those admixed with saline only. There were no significant differences in all the above mentioned activities between OK-432 and N-CWS, and there was no difference in the direct tumor inhibitory activity of the two agents in vitro. However, the administration of N-CWS had no therapeutic effect against i.p.-inoculated tumor cells while OK-432 showed a strong therapeutic effect by the same treatment schedule. Further studies are required to clarify the mechanisms responsible for the difference in the therapeutic effect of the two agents.

[Immunotherapy of acute myelogenous leukemia (AML) in adults with the Nocardia rubra cell wall skeleton]

The effect of immunotherapy with Nocardia rubra cell-wall skeleton (N-CWS) on the remission duration and survival of adults with acute myelogenous leukemia (AML) was studied in a prospective randomized controlled study. After having been induced into complete remission and consolidated, 73 patients were randomized either to maintenance chemotherapy or maintenance chemotherapy plus immunotherapy with N-CWS and irradiated allogeneic AML cells. Thirty-four patients in the chemotherapy group and 32 in the chemoimmunotherapy group were evaluable. Six months after the closure of the study, the immunotherapy showed a borderline beneficial effect on remission duration (p = 0.080) and on survival length (p = 0.098). When the data were analyzed at 42 months after entry, there was a borderline significant difference in remission duration (p = 0.066) between the two groups, prolonging the 50% remission period by 120 days, but no significant differences in survival length (p = 0.306), although the 50% survival was 168 days longer in the chemoimmunotherapy group. Thus, immunotherapy with N-CWS and irradiated allogeneic AML cells seems to be active in the treatment of adult AML when used for maintenance therapy in combination with chemotherapy.

Biological response modifiers: preclinical evaluation and clinical activity

Biological response modifiers are agents capable of affecting the host immune response toward tumors and include those biological substances produced by the human mammalian cell genome. Interferons and other lymphokines, tumor antigens, antibodies and agents which can activate or stimulate host immune responses are all included in this general category of agents. With the advent of genetic engineering and with monoclonal antibody technology, highly pure preparations of these biological substances can now be produced for tests of activity in preclinical models and in man. As the initial results accrue with highly purified preparations of interferon and with monoclonal antibodies alone or conjugated to toxic substances, the possibility of tumor specific therapy is becoming a reality. The development of preclinical models to predict for clinical activity remains a most important task to attempt to bring to clinical trials the substances most likely to be efficacious as anticancer agents. Early clinical results indicate that many of these agents can give responses in patients with clinically perceptible disease and Phase II activity studies are just beginning to define the range of clinical activity for a variety of biological response modifying agents. The development of biological response modifiers through preclinical testing and into clinical trials will be discussed in detail.

[The action of gastric mucoprotein in experimental ulcers]

Experimentally-induced ulcers in the dog (phenylquino!incarbonic acid) and in the rat (ligature of the pylorus, constriction) were treated with 20 mg/kg per day (dog) and 20 mg per animal per day (rat) of mucoprotein. The protective action excercised by this substance was demonstrated by increases in mean survival times and by the failure to apear, or by the more rapid regression, of lesions in the treated animals.