Tumor-promoting phorbol diesters inhibit in vitro antibody synthesis

Tumor-feeding artery diameter reduction is associated with improved short-term effect of hepatic arterial infusion chemotherapy plus lenvatinib treatment

BACKGROUND

Recently, hepatic arterial infusion chemotherapy (HAIC) plus lenvatinib has been frequently used to treat unresectable hepatocellular carcinoma (uHCC) in China. In the clinic, the hepatic arteries of some patients shrink significantly during this treatment, leading to improved short-term efficacy.

AIM

To investigate the relationship between the shrinkage of hepatic arteries and the short-term effect of HAIC plus lenvatinib treatment.

METHODS

Sixty-seven participants with uHCC were enrolled in this retrospective study. The patients received HAIC every 3 wk, followed by oral lenvatinib after the first HAIC course. Hepatic artery diameters were measured on CT before treatment and after 1 and 2 mo of treatment. Meanwhile, the changes in tumor capillaries were also examined on pathological specimens before and after 1 mo of treatment. The antitumor response after 1, 3, and 6 mo of treatment was assessed using the modified Response Evaluation Criteria in Solid Tumors (mRECIST). The relationship between the changes in vessel diameters and the short-term effect of the combination treatment was evaluated by receiver-operating characteristic and logistic regression analyses.

RESULTS

The hepatic artery diameters were all significantly decreased after 1 and 2 mo of treatment (P < 0.001), but there was no difference in the vessel diameters between 1 and 2 mo (P > 0.05). The microvessel density in the tumor lesions decreased significantly after 1 mo of combination treatment (P < 0.001). According to mRECIST, 46, 41, and 24 patients had complete or partial responses after 1, 3, and 6 mo of treatment, respectively, whereas 21, 21, and 32 patients had a stable or progressive disease at these times, respectively. Shrinkage of the tumor-feeding artery was significantly associated with the tumor response after 1, 3, and 6 mo of treatment (P < 0.001, P = 0.004, and P = 0.023, respectively); however, changes in other hepatic arteries were not significantly associated with the tumor response. Furthermore, shrinkage of the tumor-feeding artery was an independent factor for treatment efficacy (P = 0.001, P = 0.001, and P = 0.002 and 1, 3, and 6 mo, respectively).

CONCLUSION

The hepatic arteries shrank rapidly after treatment with HAIC plus lenvatinib, and shrinkage of the tumor-feeding artery diameter was closely related to improved short-term efficacy.

Chemotherapy-Induced Amenorrhea and Its Prognostic Significance in Premenopausal Women With Breast Cancer: An Updated Meta-Analysis

Objective

Chemotherapy-induced amenorrhea (CIA) is one of the most common side effects in premenopausal patients with breast cancer, and several factors may contribute to the incidence of CIA. In this meta-analysis, we aimed to summarize clinical risk factors associated with CIA incidence and to evaluate their prognostic effects in patients with breast cancer.

Methods

Three electronic databases (Cochrane Library, EMBASE, and MEDLINE) were systematically searched for articles published up to October 2021. The articles included clinical trials that evaluated risk factors associated with CIA and their prognostic value in treatment. For the meta-analysis, pooled odds ratio estimates (ORs) and 95% confidence intervals (CIs) were calculated using the inverse variance-weighted approach, in addition to publication bias and the chi-square test.

Results

A total of 68 studies involving 26,585 patients with breast cancer were included in this meta-analysis, and 16,927 patients developed CIA. From the 68 studies, 7 risk factors were included such as age group, hormone receptor (HR) status, estrogen receptor (ER) status, progesterone receptor (PR) status, tamoxifen administration, chemotherapeutic regimen, and tumor stage. Based on our results, patients with age of ≤40, HR-negative status, ER-negative status, PR-negative status, no use of tamoxifen, and use of anthracycline-based regimen (A) compared with anthracycline-taxane-based regimen (A+T) were associated with less incidence of CIA in patients with breast cancer. Moreover, CIA was associated with favorable disease-free survival (OR = 0.595, 95% CI = 0.537 to 0.658, p < 0.001) and overall survival (OR = 0.547, 95% CI = 0.454–0.660, p < 0.001) in premenopausal patients with breast cancer.

Conclusion

Age, HR status, ER status, PR status, tamoxifen administration, and chemotherapeutic regimen can be considered independent factors to predict the occurrence of CIA. CIA is a favorable prognostic factor in premenopausal patients with breast cancer. CIA should be a trade-off in the clinical management of premenopausal patients with breast cancer, and further large cohort studies are necessary to confirm these results.

Induction of CD8+ suppressor T cells by treatment with DMBA and TPA in vitro

Antigen-nonspecific CD8+ T suppressor cells, which suppressed delayed-type hypersensitivity (DTH) against sheep red blood cells in BALB/c mice, were induced by incubating spleen cells from mice treated with 7,12-dimethylbenz[a]anthracene (DMBA), a tumor initiator, with 12-O-tetradecanoylphorbol 13-acetate (TPA), a tumor promoter. The optimal condition was incubation in 3.2 x 10(-8) mol/5 ml of TPA for 4 days. It was shown that induction of the suppressor cells required macrophages from mice treated with DMBA. These data were consistent with the results of previous work, in which CD8+ suppressor cells were induced by painting BALB/c mice with TPA following DMBA treatment. DTH was suppressed in the culture supernatants of spleen cells from mice treated with DMBA and TPA; the suppression was genetically unrestricted. The suppressor factor was resistant to trypsin and sensitive to heating at 56 degrees C for 30 min and had affinity for the macrophages.

Effect of the ornithine decarboxylase inhibitor alpha, alpha-difluoromethylornithine on phorbol diester-induced inhibition of murine B lymphocyte differentiation

The tumor-promoting agent 12-O-tetradecanoylphorbol-13-acetate (TPA) inhibits the differentiation of murine B lymphocytes to antibody-producing plasma cells, in unfractionated spleen cell cultures or enriched B lymphocyte cultures. To determine the role of polyamines in TPA-induced inhibition, unfractionated splenic lymphocytes, in culture with antigen, were incubated with alpha, alpha-difluoromethylornithine (DFMO, 0.10 mM), an irreversible inhibitor of ornithine decarboxylase (ODC). DFMO prevented the TPA-induced inhibition of antibody forming cell number in a 5-day in vitro immunization procedure as measured by a hemolytic plaque assay. In enriched B lymphocyte cultures, however, DFMO had no comparable effect. DFMO did not prevent TPA-induced inhibition of antibody production in unfractionated spleen cell cultures but itself inhibited the amount of antibody produced. Putrescine (0.1 mM), added on day 4 of immunization, reversed DFMO inhibition of antibody production but did not enable DFMO to prevent the TPA-induced inhibition. These findings suggest that TPA-induced inhibition of plasma cell number can be mediated indirectly through effects on T lymphocytes and/or macrophages or directly through effect on B lymphocytes.

Direct inhibition of murine B lymphocyte differentiation by 12-O-tetradecanoylphorbol-13-acetate

The tumor-promoting agent, 12-O-tetradecanoylphorbol-13-acetate (TPA) inhibits the humoral immune response of lymphocytes to antigen. To test the hypothesis that this inhibition is due to a direct effect upon B lymphocytes, splenic lymphocytes or murine B lymphocytes, enriched by 'panning' splenic lymphocytes onto anti-IgM-coated petri dishes, were immunized in vitro with the thymus/accessory cell-independent antigen trinitrophenyl lipopolysaccharide (TNP-LPS) with or without TPA. The number of anti-TNP antibody-forming cells present in both lymphocyte populations after 5 days was almost completely inhibited to the same degree by TPA. These data unambiguously show that TPA can directly inhibit the differentiation of B lymphocytes to antibody-forming cells.

Suppression of the antibody response by phorbol esters in the mouse is due to an effect on the nylon wool adherent cell population

Phorbol esters, in particular 12-O-tetradecanoyl-phorbol-13-acetate (TPA), have been shown to have profound effects on most biological systems including tumor promotion. Presented here are studies on the acute toxic effects of TPA, and the effects of phorbol esters on the in vivo and in vitro, T cell-dependent, antigen-specific antibody response in the mouse. The LD50 of a single i.v. dose of TPA in the mouse was 309 micrograms/kg. Acute toxic effects included lethargy, hypothermia and enlarged, hemorrhagic spleens at the higher doses. TPA was shown to be a potent inhibitor of the in vivo primary antibody response as measured by the IgM antibody-forming cell (AFC) response to sheep red blood cells (sRBC). The ED50 of a cumulative i.v. dose was 145 micrograms/kg administered the day before and the day of immunization (72.5 micrograms/kg/day). A cumulative dose of 500 micrograms/kg (250 micrograms/kg/day) resulted in a 100% suppression of the response. This in vivo exposure to TPA did not alter B cell/T cell ratio in the spleen. Phorbol ester analogs inactive in other biological systems were also inactive in the in vivo AFC response. The in vitro AFC assay was used to determine what cell type was being affected by TPA. Separation of the adherent spleen cells into B and T cell populations was done using nylon wool columns and anti-theta plus complement treatment. Experiments with these cell populations indicated that TPA produced suppression of the response due to an effect on the nylon wool adherent cell population.