Antineoplastic Chemotherapeutic Agents Research Articles

Abstract 6333: Repurposing NSAIDs for chemo-immunotherapy: mechanisms beyond COX inhibition

Abstract It has been well-established that some nonsteroidal anti-inflammatory drugs (NSAIDs) have antitumor activities. The beneficial effects of these NSAIDs are mainly attributed to their ability to inhibit the production and activity of cyclooxygenases (COX1 and COX2) and prostaglandin (PGE2), which are known to promote tumor progression, angiogenesis, metastasis and immunosuppression. We recently reported that administration of indomethacin, a prototypical NSAID, can enhance the antitumor efficacy of adoptive T cell therapy in animal models. However, currently adoptive T cell therapy as a treatment option is only suitable for selected patients with certain types of cancer. Here, we set out to explore the utility of indomethacin in a chemo-immunotherapy setting that is readily applicable to a wide range of cancers. Cyclophosphamide (CTX) is a widely used antineoplastic chemotherapeutic agent with immunostimulatory activities when used at low-medium doses. We show that indomethacin had no impact on tumor growth but can significantly enhance the antitumor effect of CTX in multiple mouse tumor models. The beneficial effect of indomethacin was diminished in immunodeficient mice or CD8 T cell-depleted wild-type mice, indicating the requirement for the host immunity. Furthermore, the CTX and indomethacin regimen can sensitize tumors to anti-PD1 immunotherapy. scRNAseq analysis of tumor samples revealed the impact of indomethacin on the tumor microenvironment. Our data also indicate that the immunopotentiating effect of indomethacin can be independent of PGE2 inhibition, and involves the TRAIL-DR5 axis in promoting tumor regression. Other potential mechanisms, including modulation of chronic interferon signaling in tumor cells, have also been investigated. Altogether, our study sheds light on the multiple mechanisms underlying indomethacin’s beneficial effects, and highlights the potential of NSAID administration as a readily applicable and cost-effective approach to augment the efficacy of chemo-immunotherapy. Citation Format: Ogacheko D. Okoko, Md Y. Gazi, Xin Wang, Caitlin Brandle, Mercy Kehinde-Ige, Gary A. Piazza, Huidong Shi, Gang Zhou. Repurposing NSAIDs for chemo-immunotherapy: mechanisms beyond COX inhibition [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 6333.

Abstract 3042: BXQ-350 may protect peripheral nerves from the direct cytotoxicity of chemotherapeutic agents leading to chemotherapy induced peripheral neuropathy

Abstract Background: Chemotherapy Induced Peripheral Neuropathy (CIPN) is a debilitating side effect associated with many antineoplastic chemotherapeutic agents including cytotoxic and targeted agents. It significantly impacts cancer patients’ quality of life during treatment, and may cause lasting neuropathy and shorten treatment regimen, potentially impacting clinical benefit. The pathology of CIPN is complex and still not completely understood. Damages to nerve cells are believed to be directly resulting from the antineoplastic agents’ cytotoxicity, and inflammation and the immune system are believed to be involved as well. Evidence suggests that intervention of certain GPCRs (e.g., cannabinoid receptors and others) may be useful as potential treatments. Altered neuronal sphingolipid metabolism has been linked to neuropathic pain and elevated plasma levels of sphingosine-1-phosphate (S1P) have also been associated with patients receiving chemotherapy and developing CIPN; therefore, modulating S1P levels may also be a potential treatment. Method: BXQ-350 is a nanovesicle of Saposin C, an allosteric activator of sphingolipid metabolism, that lowers systemic S1P; Saposin C has been reported to activate certain GPCRs, including GPR37. BXQ-350 was investigated in an adult Phase 1 dose-escalation safety study in heavily pretreated all-comer cancer patients with advanced solid malignancies (NCT02859857). The cytoprotective properties of BXQ-350 against multiple agents known to induce CIPN were investigated in vitro in neuronal PC12 cells and BXQ-350’s CIPN mitigation properties were investigated in vivo in a CIPN preclinical model. Results: A pancreatic cancer patient with chronic CIPN at time of enrollment in the Phase 1 study spontaneously reported a significant improvement of her neuropathic symptoms shortly after receiving BXQ-350; several patients had similar improvements. Results from preclinical experiments in PC12 cells revealed that BXQ-350 at concentration as low as 50 nM protected cells from oxaliplatin, paclitaxel, bortezomib or MMAE and promoted neurite growth. BXQ-350 was subsequently investigated in a murine oxaliplatin-induced CIPN preclinical model, showing a dose-dependent reduction of thermal and mechanical allodynia correlating with decreasing systemic S1P levels. Conclusions: Preclinical results demonstrated that BXQ-350 was highly effective at protecting neuronal cells from antineoplastic agents known to induce CIPN and prevent CIPN in a preclinical model. These results appeared to support the clinical observation that BXQ-350 alleviated CIPN symptoms in several patients soon after receiving BXQ-350. Additional studies are on-going. Citation Format: Nikhil Wilkins, Tim Stephens, Robin Furnish, Charlie Cruze, Darren Wolfe, Gilles H. Tapolsky, Ray Takigiku. BXQ-350 may protect peripheral nerves from the direct cytotoxicity of chemotherapeutic agents leading to chemotherapy induced peripheral neuropathy [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 3042.

CB1 as a novel target for Ginkgo biloba'sterpene trilactone for controlling chemotherapy-induced peripheral neuropathy (CIPN).

The application of antineoplastic chemotherapeutic agents causes a common side effect known as chemotherapy-induced peripheral neuropathy (CIPN) that leads to reducing the quality of patient's life. This research involves the performance of molecular docking and molecular dynamic (MD) simulation studies to explore the impact ofterpenoids ofGinkgo bilobaon the targets (CB-1, TLR4, FAAH-1, COX-1, COX-2) that can significantly affect the controlling of CIPN's symptoms. According to the in-vitro and in-vivo investigations, terpenoids, particularly ginkgolides B, A, and bilobalide, can cause significant effects on neuropathic pain. The molecular docking results disclosed the tendency of our ligands to interact with mainly CB1 and FAAH-1, as well as partly with TLR4, throughout their interactions with targets. Terpene trilactone can exhibit a lower rate of binding energy than CB1's inhibitor (7dy), while being precisely located in the CB1's active site and capable of inducing stable interactions by forming hydrogen bonds. The analyses of MD simulation proved that ginkgolide B was a more suitable activator and inhibitor for CB1 and TLR4, respectively, when compared to bilobalide and ginkgolide A. Moreover, bilobalide is capable of inhibiting FAAH-1 more effectively than the two other ligands. According to the analyses of ADME, every three ligands followed the Lipinski's rule of five. Considering these facts, the exertion of three ligands is recommended for their anti-inflammatory, neuroprotective, and anti-nociception influences caused by primarily activating CB1 and inhibiting FAAH-1 and TLR4; in this regard, these compounds can stand as potential candidates for the control and treatment of CIPN's symptoms.

Angico Gum suppresses inflammatory responses and maintains tissue integrity through the NO and COX‐2 pathway in intestinal mucositis induced by 5‐fluorouracil

Intestinal homeostasis has often been referred to as a state of controlled inflammation, in which pro‐ and anti‐inflammatory factors function in a synchronous manner. In this context, intestinal mucositis can be deemed as an inflammatory pathophysiological process, which results in morphological and physiological changes in the intestinal mucosa of the gastrointestinal tract. Its emergence is due to the administration of antineoplastic agents, such as 5‐fluorouracil (5‐FU), an antimetabolite, during cancer therapy (1). With high rates of morbidity and mortality, mucositis still represents an obstacle in the treatment of cancer due to the lack of an effective treatment. Numerous studies have explored natural products and secondary metabolites from medicinal plants such as natural gums to find compounds having pharmacological activity against various human health disorders. Angico (Anadenanthera colubrina (Vell.)) is a plant of the Fabaceae family prevalent in the Brazilian ecosystems of the Cerrado and Caatinga (4). Angico has been reported to possess medicinal properties for the treatment of diarrhea, cough, bronchitis, and inflammation (5). Secondary metabolites such as steroids, flavonoids, terpenes, andphenolic derivatives can be extracted from the bark of A. colubrina (6) that can function as antioxidants, antimicrobials, and anti‐inflammatory, anti‐proliferative, antiallergic, antithrombotic, and antiviral agents (7). In the present study, we aimed to evaluate the effect of AG on experimental intestinal mucositis induced by 5‐FU. Swiss mice were randomly divided into nine groups: Saline, 5‐FU, AG‐100, AG‐400, Celecoxib (CLX), CLX + AG‐400, L‐NAME, L‐Arginine, and AG + L‐NAME. The animals were euthanized, then, blood and segments of the small intestine were collected to evaluate histopathological, levels of malondialdehyde (MDA) and Nitrite/Nitrate (NOx), leukocytes, mast and goblet cell counts, and immunohistochemical analysis of induced nitric oxide synthase (iNOS) and cyclooxygenase‐2 (COX‐2). AG prevents morphofunctional changes in experimental intestinal mucositis due to 5‐FU by attenuating inflammation, oxidative stress, tissue damage, mastocytosis, and leukopenia. These results suggest that the NO and COX‐2 pathways are possible mechanisms mediating the protective effect of AG on intestinal mucositis induced by antineoplastic chemotherapeutic agents such as 5‐FU.

Review of Pharmacotherapy for Tinnitus.

Various medications are currently used in the treatment of tinnitus, including anesthetics, antiarrhythmics, anticonvulsants, antidepressants, antihistamines, antipsychotics, anxiolytics, calcium channel blockers, cholinergic antagonists, NMDA antagonists, muscle relaxants, vasodilators, and vitamins. To date, however, no medications have been specifically approved to treat tinnitus by the US Food and Drug Administration (FDA). In addition, medicines used to treat other diseases, as well as foods and other ingested materials, can result in unwanted tinnitus. These include alcohol, antineoplastic chemotherapeutic agents and heavy metals, antimetabolites, antitumor agents, antibiotics, caffeine, cocaine, marijuana, nonnarcotic analgesics and antipyretics, ototoxic antibiotics and diuretics, oral contraceptives, quinine and chloroquine, and salicylates. This review, therefore, describes the medications currently used to treat tinnitus, including their mechanisms of action, therapeutic effects, dosages, and side-effects. In addition, this review describes the medications, foods, and other ingested agents that can induce unwanted tinnitus, as well as their mechanisms of action.

Rosuvastatin and simvastatin attenuate cisplatin-induced cardiotoxicity via disruption of endoplasmic reticulum stress-mediated apoptotic death in rats: targeting ER-Chaperone GRP78 and Calpain-1 pathways

Cisplatin (CP) is a powerful antineoplastic chemotherapeutic agent with broad-spectrum properties. Acute and cumulative cardiotoxicity are major limiting factors for CP therapy. Various pathogenic pathways have been suggested to CP-induced cardiotoxicity; oxidative damage, ER stress, and programmed cell death/apoptosis. The present study aimed to assess the signaling mechanisms related to the advantageous effects of rosuvastatin (RSV) and simvastatin (SMV) against CP-related cardiac ER stress dependent apoptotic death in rats. Acute cardiotoxicity was induced by a single dose of CP (10 mg/kg, i.p.) on the 10th day of the experiment. RSV (10 mg/ kg/day) and SMV (10 mg/kg/day) were orally administered for 15 days. CP-treated rats showed significant alterations in electrocardiographic recordings and elevation in serum cardiac function biomarkers; troponin T content, lactate dehydrogenase and creatine kinase-MB levels as well as boost in the cardiac oxidative stress biomarkers. In addition, CP exposure resulted in GRP78 induction; an ER stress and elevation marker at calpain-1 content as well as activation of activated caspase-3 (ACASP3) and caspase-12 were reflected on CP-triggered apoptosis evidenced by elevation in the Bax/Bcl-2 ratio. However, RSV and SMV administration mitigate those adverse CP effects. Statins administration prominently alleviated CP-induced cardiac abnormalities exerting improvement in the ECG pattern and cardiac enzyme biomarkers. Interestingly, statins; RSV and SMV, disrupted CP-induced ER stress and the consequent apoptotic cell death evidenced by downregulation of ER-chaperone GRP78, calpain-1, ACASP3 and caspase-12 as well as decline in the Bax/Bcl-2 ratio. From all the previous findings, it can be suggested that statins namely; RSV and SMV, play protective role against CP-induced cardiac injury by regulating ER stress-mediated apoptotic pathways.

Genotoxic Effects of the Anti-Cancer Drug Doxorubicin (Dxr) in the Bone Marrow Cells of Swiss Albino Mice (Mus musculus)

The antineoplastic chemotherapeutic agent doxorubicin (DXR) is probably the most utilized drug for treating many human cancers. In the current study we aimed to evaluate the genotoxic effects of doxorubicin Swiss mice bone marrow cells using the toxicological endpoints chromosomal aberrations, mitotic index and micronuclei formation. Twelve male animals, aged 6-8 weeks and weighing 24±2g were divided into four groups. One group served as control was intraperitoneally injected only with distilled water. The three remaining groups were injected intraperitoneally with single doses of doxorubicin (0.2, 0.4 and 0.8 mg/g body weight) for two consecutive days. 24 hours later, animals were anaesthetized and killed by cervical dislocation. Colchicine (0.05 %) was injected to animals 90 minutes before sacrifice. After sacrificing the animals, both femurs were dissected out and the bone marrow cells obtained. All treatments with doxorubicin caused an increased significance in the incidence of chromosomal aberrations (CA) and micronuclei formation in polychromatic erythrocytes (PCEs) cells. Meanwhile, there was a gradual repression in the mitotic index (MI) percentages of the treated groups compared to that of the control. Different types of chromosomal aberrations (structural and numerical) were induced as a result of doxorubicin treatments. These includes: gaps, breaks, fragments, rings, centric fusions (CF) and polyploidy. The mean percentages of total chromosomal aberrations increased from 3.33 ± 0.28 in the control group to 12.67 ± 2.42, 29.00 ± 4.27 and 38.67 ± 2.82 for doses 0.2, 0.4 and 0.8 mg/kg B.W. respectively. The numbers of micronucleated PCEs observed in mice cells treated with doxorubicin were increased from 4.67±0.48 for the control group to 7.00±1.02, 10.67±2.10 and 17.67 for the three doses respectively. Meanwhile, the PCE / (PCE+NCE) ratio calculated in treated animals were 0.85 ± 0.02, 0.63 ± 0.08 and 0.54 ± 0.10 compared to 0.94 ± 0.12 for the control. Our results indicated that doxorubicin has genotoxic as well as cytotoxic effects in mice bone marrow cells.

Hepatic protective effect of grape seed proanthocyanidin extract against Gleevec-induced apoptosis, liver Injury and Ki67 alterations in rats

ABSTRACT Gleevec (imatinib) is an antineoplastic chemotherapeutic agent used in the treatment of many types of cancer. The current study was conducted to examine the possible modifying effects of grape seeds proanthocyandins extract (GSPE) against apoptosis, liver injury and Ki67 alterations induced by Gleevec in male rats. 40 male albino rats were equally divided into four groups (First and second groups were control and GSPE groups; third group was Gleevec group and fourth group was treated with Gleevec and GSPE). Gleevec induced elevations in P53 and depletion of Bcl2 levels in liver tissues were compared with the control group. Liver sections in rats treated with Gleevec exhibited marked cellular infiltrations, vacuolar degeneration hepatocytes, numerous apoptotic cells, and congestion in central and portal veins, as well as a significant increase in the proliferating of Ki67 after Gleevec injection as compared with control group. In contrast, treatment with Gleevec and GSPE showed a moderate to good degree of improvement in hepatocytes with a significant increase in Ki67, a decrease in P53 and an increase in Bcl2 levels in liver tissues compared to treatment with Gleevec. Therefore, Gleevec induces apoptosis, injury and Ki67 changes in rat liver, whereas GSPE modulates these alternations.

Current aspects of ototoxicity. Ototoxic substances and their effects

Ototoxicity describes reversible or irreversible disorders of inner ear functions due to the influence of chemical, biological, or physical substances. Ototoxicity should be kept in mind during differential diagnosis of hearing loss, tinnitus, dizziness, and vertigo. In clinical practice, drug-induced ototoxic effects play a major role. The otorhinolaryngologist should also be involved in interdisciplinary cooperation, e.g., during treatment with antineoplastic chemotherapeutic agents with potential ototoxic side effects. In clinical practice, multimedication and interactions between different agents can complicate precise correlation in individual cases. Recent studies also show that noncellular components, such as otoconia, are extremely sensitive to chemical attacks.

Critical Serum-Selenium Levels in APL and MM Patients during ATO-Treatment (According to APL and MAC/DAC Schemes)

IntroductionArsenic trioxide (As2O3; ATO; Trisenox®) is an antineoplastic chemotherapeutic agent used for the treatment of acute promyelocytic leukemia (APL) and experimentally also for other malignancies including multiple myeloma (MM). As the therapeutic doses are rather high, and arsenic-selenium interactions well-known (arsenic complexation by selenium with subsequent excretion by bile), we assume that arsenic interferes in the selenium (Se) metabolism during the treatment. As selenium deficiency (<40 ng Se/g) can be detrimental in many ways, the aim of our study was to follow serum-selenium levels in APL and MM patients during ATO treatment.PatientsOver a period of 10 years, 20 patients (8 APL, 12 MM) were treated by ATO (administered as 2-h intravenous infusions). APL patients were previously treated according to a standard APL EORTC protocol. In 3 patients the ATO was started immediately after an interruption of treatment due to a differentiation syndrome and in the remaining 5 patients ATO was started due to relapse. ATO (0.15 mg/L) was administered for i) 50 consecutive days and prolonged for 25 days (5 days/week) after a 3-weeks break or for ii) 25 consecutive days repeated after a 1-week break.The majority of 12 MM patients was heavily pretreated, relapsed or refractory. ATO (0.25 mg/kg) infusion was followed by injection of ascorbic acid (1 g); Melphalan (0.1 mg/kg) and Dexamethasone (40 mg/kg) were added according to a MAC and DAC scheme, respectively. ATO was given in cycles (4 consecutive days followed by 3 weeks of 2 applications/week). Treatment efficacy was evaluated by measurement of a monoclonal spike, except for patients with a Bence-Jones type of MM who were only clinically evaluated.Sampling and analytical methodsThe urine and blood samples were taken before ATO infusion and total selenium was analyzed using inductively coupled plasma mass spectrometry (ICP-MS).ResultsAll APL patients reached a stable molecular remission. In contrast, the efficacy of the ATO treatment in MM patients was difficult to evaluate due to the patients’ poor initial condition. In 3 MM patients the effect of ATO could not be evaluated since they deceased during the treatment. In 4 out of 9 remaining MM patients at least a partial remission occurred. Differences between both groups were also reflected in selenium-serum levels at the beginning and during the therapy. The average selenium-serum level of the APL group at the beginning of the treatment was in the range of the general population and almost two times higher than the average of the MM group (88.4 ± 17.8 ng/g, n = 5 vs. 54.6 ± 18.8 ng/g, n =10; Figure 1A). During the ATO treatment the serum-selenium levels fell significantly in both groups – final levels for APL patients were mostly around 50 ng/g and for MM patients below 40 ng/g (Figure 1B). In the urine of all patients a diminished selenium-excretion was observed during treatment.ConclusionsAlmost all APL patients receiving ATO daily responded well to the treatment while the positive treatment-response of MM patients was limited, possibly due to their pretreatment status and/or a suboptimal treatment protocol. Low serum-selenium levels (<40 ng/ml) are frequently related to a compromised immune system. Hence, low initial selenium levels and even lower final selenium levels in MM patients may increase their vulnerability to infections and ATO side-effects. [Display omitted] [Display omitted] DisclosuresOff Label Use: Arsenic trioxide, drug with known antimyeloma activity. It was used as salvage options in multiple myeloma pts., in whom all other conventional treatment options were exhausted. Those patients would be otherwise treated only in a paliative way. They all wrote informed consent after we discussed the issue with them.

ChemoImmunoModulation: Immune Regulation by the Antineoplastic Chemotherapeutic Agents

Since 1948, when Farber et al. introduced aminopterin, the first chemotherapeutic agent, more than 100 such agents have come into use. Initially, antitumor chemotherapies were thought to produce only antiproliferative or cytotoxic effects on dividing tumor cells as it was often associated with the damage to healthy tissues and the development of resistant tumor clones. However, that view has been changing as a consequence of recent demonstrations that several antineoplastic drugs, even at low doses, have antiangiogenic and sometimes immunomodulating effects. In addition, new studies indicate that lowering the dose of conventional cytotoxic agents and combining chemotherapy with other modalities may not only decrease the toxicity of conventional chemotherapy, but also up-regulate the efficacy of different anticancer therapies. Giving chemotherapy in this manner has several potential advantages, including impediment of the onset of mutation-dependent mechanisms of acquired drug resistance and increase in the efficacy and durability of combinatorial therapeutic modalities. Certain "immunogenic" forms of cancer chemotherapy may cause indirect activation of immune cells due to the accessibility of tumor antigens and certain "danger" signals. Furthermore, new findings indicate that several chemotherapeutic agents can directly activate immune cells when used in ultra low noncytotoxic concentrations, the new phenomenon that was termed chemoimmunomodulation. The goal of this review is to analyze the immune modulating properties of antineoplastic chemotherapeutic agents and present new evidence of the immunostimulating potentials of several agents used in low and ultra low nontoxic doses. Therapeutic potentials of combined chemo-immunotherapeutic regimens have been extensively reviewed in a variety of recent publications and will not be discussed.

Chemotherapy-Knowledge and Handling Practice of Nurses Working in a Medical University of Nepal

Background: Many antineoplastic agents are known to be teratogenic and mutagenic to humans. Nurses are the main groups that are exposed to these drugs in hospital setting. Generally, the occupational activities that pose to greatest risk of exposure are the preparation and administration of antineoplastic agents, cleaning of chemotherapy spills, and handling of patient excreta. Objective: The objectives of this study were to evaluate the knowledge of nurse regarding the way of exposure of Cytotoxic Drugs (CDs) and to determine the current patterns of use of personal protective equipments while handling antineoplastic chemotherapeutic agents. Methods: An analytic cross sectional study was carried out at BPKIHS Dharan. The study was carried out on 125 nurses. The random sampling technique was used to select the study subjects using structured and semi-structured questionnaire. Collected data were analyzed using descriptive and inferential statistics. Result: More than 92% of participants reported usually wearing gloves during chemotherapy handling; 6% reported using laboratory coats as protective garments. Usual use of face and respiratory protection was less than 5%. Chemotherapy was reported to be prepared in nursing station where there are no laminar airflow hoods in 100% of work settings. None of the subjects have reportedly provided any type of medical monitoring. Conclusion: Use and availability of gloves have increased but personal protective equipment like protective garments, face and respiratory protective, when handling chemotherapy have decreased and medical monitoring of exposed employees still is neither widely practiced nor consistent with Occupational Safety and Health Administration (OSHA) guidelines.

Chemotherapeutic agents in low noncytotoxic concentrations increase immunogenicity of human colon cancer cells

We have recently reported that chemotherapeutic agents in ultra low noncytotoxic concentrations may block the ability of tumor cells to suppress functional activation of dendritic cells (DCs). HCT-116 human colon cancer cells were treated with 0.5 nM paclitaxel (PAC) or 2 nM doxorubicin (DOX) with the aim of defining the immunogenic changes induced by ultra low noncytotoxic concentrations of antineoplastic chemotherapeutic agents. Genetic alterations were screened by DNA microarray that revealed increased expression of genes involved in antigen processing and presentation, including the heat-shock protein, calmodulin, and proteasome 26 genes. As the proteins encoded by these genes are involved in the cytosolic route of antigen processing machinery, we next evaluated whether PAC and DOX in noncytotoxic concentrations changed expression of MHC class I antigen processing machinery (APM) components in three different colon cancer cell lines. Our results showed that PAC and DOX increased the intracellular expression of APM proteins, including calmodulin, LMP2, LMP7, TAP1 and tapasin. The biological significance of modulation of antigen processing and presentation proteins in tumor cells by ultra low nontoxic concentrations of chemotherapeutic drugs was revealed when non-treated and treated tumor cells were used as a source of tumor antigens for the generation of tumor-specific cytotoxic T cells (CTLs) in vitro. We demonstrated that (i) DCs that engulf tumor cells pretreated with noncytotoxic concentrations of chemotherapeutic agents induced CTLs with a higher cytotoxic potential than DCs loaded with nontreated tumor cells, and (ii) CTLs induced by tumor lysate-pulsed DCs killed live tumor cells more efficiently if these tumor cells were pretreated with noncytotoxic concentrations of chemotherapeutic drugs. These results demonstrate that chemomodulation of human tumor cells with noncytotoxic concentrations of chemotherapeutic agents increases tumor immunogenicity and results in the generation of more efficient DC vaccines and CTLs, which can be used for cell-based anticancer immunotherapies.

Treatment induced necrosis versus recurrent/progressing brain tumor: going beyond the boundaries of conventional morphologic imaging

Brain tumor patients undergo various combinations therapies, leading to very complex and confusing imaging appearances on follow up MR imaging and hence, differentiating recurrent or progressing tumors from treatment induced necrosis or effects has always been a challenge in neuro-oncologic imaging. This particular topic has become more relevant these days because of the advent of newer anti-angiogenic and anti-neoplastic chemotherapeutic agents as well as use of salvage radiation therapy. Various clinically available functional imaging modalities can provide additional physiologic and metabolic information about the tumors which could be useful in identifying viable tumor from treatment induced necrosis and hence, can guide treatment planning. In this review we will discuss various functional neuro-imaging modalities, their advantages and limitations and also their utility in treatment planning.

Chemotherapeutic Agents in Noncytotoxic Concentrations Increase Antigen Presentation by Dendritic Cells via an IL-12-Dependent Mechanism

Antineoplastic chemotherapeutic agents may indirectly activate dendritic cells (DCs) by inducing the release of "danger" signals from dying tumor cells. Whereas the direct cytotoxic or inhibitory effect of conventional chemotherapy on DCs has been reported, modulation of DC function by chemotherapeutic agents in low noncytotoxic concentrations has not yet been investigated. We have tested the effects of different classes of antineoplastic chemotherapeutic agents used in low noncytotoxic concentrations on the Ag-presenting function of DCs. We revealed that paclitaxel, doxorubicin, mitomycin C, and methotrexate up-regulated the ability of DCs to present Ags to Ag-specific T cells. Stimulation of DC function was associated with the up-regulation of expression of Ag-processing machinery components and costimulatory molecules on DCs, as well as increased IL-12p70 expression. However, the ability of DCs treated with paclitaxel, methotrexate, doxorubicin, and vinblastine to increase Ag presentation to Ag-specific T cells was abolished in DCs generated from IL-12 knockout mice, indicating that up-regulation of Ag presentation by DCs is IL-12-dependent and mediated by the autocrine or paracrine mechanisms. At the same time, IL-12 knockout and wild-type DCs demonstrated similar capacity to up-regulate OVA presentation after their pretreatment with low concentrations of mitomycin C and vincristine, suggesting that these agents do not utilize IL-12-mediated pathways in DCs for stimulating Ag presentation. These findings reveal a new mechanism of immunopotentiating activity of chemotherapeutic agents-a direct immunostimulatory effect on DCs (chemomodulation)-and thus provide a strong rationale for further assessment of low-dose chemotherapy given with DC vaccines for cancer treatment.

Inhibition of IκB Kinase Subunit 2 in Cutaneous T-Cell Lymphoma Down-Regulates Nuclear Factor-κB Constitutive Activation, Induces Cell Death, and Potentiates the Apoptotic Response to Antineoplastic Chemotherapeutic Agents

A key molecular feature of cutaneous T-cell lymphomas (CTCL) is the constitutive activation of the nuclear factor-kappaB (NF-kappaB) transcription factor. We investigated in vitro the effects on CTCL survival and chemoresistance of a specific inhibition of IkappaB kinase subunit 2 (IKK2). Selective IKK2 inhibition was carried out by transfection of SeAx and MyLa CTCL lines with an inactive form of IKK2 and by exposing these lines and tumor cells from 10 patients with Sézary syndrome (SS) to AS602868, a new IKK2 inhibitor. The constitutive nuclear translocation of NF-kappaB was analyzed by electrophoretic mobility shift assay and confocal microscopy. Apoptosis was determined by Annexin V/propidium iodide-positive staining and mitochondrial transmembrane potential alterations as well as poly(ADP-ribose)polymerase cleavage. The expression of Bcl-2 family oncoproteins and survivin was studied by immunoblotting. Specific IKK2 inhibition resulting from transfection or from incubation with AS602868 allowed a down-regulation of NF-kappaB transcriptional activity. As shown by electrophoretic mobility shift assay and apoptosis assays, AS602868 down-regulated the nuclear translocation of NF-kappaB and induced a potent apoptotic response in CTCL lines and in tumor cells from patients with SS while preserving the viability of both peripheral blood lymphocytes from healthy donors and of nonmalignant T cells from SS patients. Moreover, CTCL death induction by conventional antineoplastic agents etoposide and vincristine was potentiated by AS602868. Finally, AS602868-induced apoptosis of CTCL cells was associated with an up-regulation of Bax dimers and a decrease of survivin. These results indicate that IKK2 inhibition represents a promising strategy for the treatment of advanced stages of CTCL.

Restoration of Reproductive Potential after Autotransplantation of Frozen Ovaries in Mice Pretreated with Cyclophosphamide

Purpose: Infertility due to ovarian failure that is caused by antineoplastic chemotherapeutic agents is one of the primary problems of female cancer patients who are in their reproductive years. It has become important to preserve the reproductive potential of female cancer patients. This study was conducted to determine whether autotransplantation of frozen ovaries can restore reproductive potential. Methods: This study included 30 female mice that had normal reproductive potential. The mice were divided into 4 groups: the positive control, the negative control, the comparison group, and the experimental group. The positive control group received right total oophorectomy, and the negative control group received bilateral total oophorectomy. Greater than or equal to 90% of the left ovary was removed in the mice of the comparison group, and then cyclophosphamide was administered. In the experimental group, the right ovary taken out by right total oophorectomy, and this was crypreserved using the vitrification method. And then cyclophosphamide was administered. The cryopreserved ovary was autotransplanted to the left gonadal fat pad after greater than or equal to 90% of the left ovary was removed. The reproductive performance in each group was analyzed according to the pregnancy rate after mating. Results: In the positive control group, all five mice became pregnant, and the number of fetuses was 4 to 5 (mean= 4.60±0.55). In the comparison group, the pregnancy rate was 50%, and the mean number of fetuses was 1.40±0.55. In the experimental group, 7 of 10 (70%) mice became pregnant, and the mean number of fetuses was 4.71±2.56. There was no significant difference in the number of fetuses between the positive control and the experimental group (p=0.093), but there was a significant difference in the number of fetuses between the comparison group and the experimental group (p=0.019). Conclusion: The results of this study suggest that autotransplantation of frozen ovaries using the vitrification method may restore the impaired ovarian function induced by antineoplastic chemotherapeutic agents.

Preclinical Efficacy of the c-Met Inhibitor CE-355621 in a U87 MG Mouse Xenograft Model Evaluated by18F-FDG Small-Animal PET

The purpose of this study was to evaluate the efficacy of CE-355621, a novel antibody against c-Met, in a subcutaneous U87 MG xenograft mouse model using (18)F-FDG small-animal PET. CE-355621 or control vehicle was administered intraperitoneally into nude mice (drug-treated group, n = 12; control group, n = 14) with U87 MG subcutaneous tumor xenografts. Drug efficacy was evaluated over 2 wk using (18)F-FDG small-animal PET and compared with tumor volume growth curves. The maximum %ID/g (percentage injected dose per gram of tissue) of (18)F-FDG accumulation in mice treated with CE-355621 remained essentially unchanged over 2 wk, whereas the %ID/g of the control tumors increased 66% compared with the baseline. Significant inhibition of (18)F-FDG accumulation was seen 3 d after drug treatment, which was earlier than the inhibition of tumor volume growth seen at 7 d after drug treatment. CE-355621 is an efficacious novel antineoplastic chemotherapeutic agent that inhibits (18)F-FDG accumulation earlier than tumor volume changes in a mouse xenograft model. These results support the use of (18)F-FDG PET to assess early tumor response for CE-355621.

Cyclophosphamide as a potent inhibitor of tumor thioredoxin reductase in vivo

Cyclophosphamide (CTX) is in the nitrogen mustard group of alkylating antineoplastic chemotherapeutic agents. It is one of the most frequently used antitumor agents for the treatment of a broad spectrum of human cancers. Thioredoxin reductase (TrxR) catalyze the NADPH-dependent reduction of thioredoxin and play an important role in multiple cellular events related to carcinogenesis including cell proliferation, apoptosis, and cell signaling. This enzyme represents a promising target for the development of cytostatic agents. The purpose of this study is to determine whether CTX could target TrxR in vivo. Lewis lung carcinoma and solid H22 hepatoma treated with 50-250 mg/kg CTX for 3 h lost TrxR activity in a dose-dependent fashion. Over 75% and 95% of TrxR activity was lost at the dose of 250 mg/kg. There was, however, a recovery of TrxR activity such that it attained normal levels by 120 h after a dose of 250 mg/kg. In addition, we found that CTX caused a preferential TrxR inhibition over other antioxidant enzymes, such as glutathione peroxidase, catalase, and superoxide dismutase. We also used ascites H22 cells to investigate cancer cells response after TrxR was inhibited by CTX in vivo since CTX is needed to be activated by liver cytochrome P450 enzymes. The time course and dose-dependent changes of cellular TrxR activity were similar with those in tumor tissue. CTX caused a dose-dependent cellular proliferation inhibition which was positively correlated with TrxR inhibition at 3 h. Furthermore, when 3 h CTX-treated cells with various TrxR backgrounds, harvested from ascites-bearing mice, were implanted into mice, the proliferations of these cells were again proportionally dependent on TrxR activity. The TrxR inhibition could thereby be considered as a crucial mechanism contributing to anticancer effect seen upon clinical use of CTX.

Doxycycline induces expression of P glycoprotein in MCF-7 breast carcinoma cells.

P-glycoprotein (P-gp) overexpression by tumor cells imparts resistance to multiple antineoplastic chemotherapeutic agents (multiple drug resistance). Treatment of tumor cells with chemotherapeutic agents such as anthracyclines, epipodophyllotoxins, and Vinca alkaloids results in induction of P-gp expression. This study was performed to determine if clinically relevant antimicrobial drugs (i.e., drugs that are used to treat bacterial infections in cancer patients) other than antineoplastic agents can induce expression of P-gp in MCF-7 breast carcinoma cells. Expression of P-gp and MDR1 mRNA was determined in samples from MCF-7 cells that were treated in culture with doxorubicin (positive control) and the antimicrobial drugs doxycycline, piperacillin, and cefoperazone. The functional status of P-gp was assessed using laser cytometry to determine intracellular doxorubicin concentrations. The MTT (3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide) assay was used to determine if the cytotoxicity of experimental drugs was related to their ability to induce P-gp expression. MCF-7 cells treated with doxycycline (MCF-7/doxy) were stimulated to overexpress P-gp, whereas cells treated with piperacillin and cefoperazone did not overexpress P-gp. MCF-7/doxy cells were compared to a positive-control subline, MCF-7/Adr, previously selected for doxorubicin resistance, and to MCF-7 cells treated with doxorubicin (MCF-7/doxo). All three sublines overexpressed P-gp and MDR1 mRNA and accumulated less intracellular doxorubicin than did control MCF-7 cells. P-gp expression was induced only by experimental drugs that were cytotoxic (doxorubicin and doxycycline). Doxycycline, a drug that has been used for treatment of bacterial infections in cancer patients, can induce functional P-gp expression in cancer cells, resulting in multidrug resistance.