The tumor suppressor p53 is considered the “guardian of the genome” that can protect cells against cancer by inducing cell cycle arrest followed by cell death. However, STAT3 is constitutively activated in several human cancers and plays crucial roles in promoting cancer cell proliferation and survival. Hence, STAT3 and p53 have opposing roles in cellular pathway regulation, as activation of STAT3 upregulates the survival pathway, whereas p53 triggers the apoptotic pathway. Constitutive activation of STAT3 and gain or loss of p53 function due to mutations are the most frequent events in numerous cancer types. Several studies have reported the association of STAT3 and/or p53 mutations with drug resistance in cancer treatment. This review discusses the relationship between STAT3 and p53 status in cancer, the molecular mechanism underlying the negative regulation of p53 by STAT3, and vice versa. Moreover, it underlines prospective therapies targeting both STAT3 and p53 to enhance chemotherapeutic outcomes.

The recently discovered interleukin (IL)- 32 isoform IL-32θ exerts anti-metastatic effects in the breast tumor microenvironment. However, the involvement of IL-32θ in breast cancer cell proliferation is not yet fully understood; therefore, the current study aimed to determine how IL-32θ affects cancer cell growth and evaluated the responses of IL-32θ-expressing cells to other cancer therapy. We compared the functions of IL-32θ in triple-negative breast cancer MDA-MB-231 cells that stably express IL-32θ, with MDA-MB-231 cells transfected with a mock vector. Slower growth was observed in cells expressing IL-32θ than in control cells, and changes were noted in nuclear morphology, mitotic division, and nucleolar size between the two groups of cells. Interleukin-32θ significantly reduced the colony-forming ability of MDA-MB-231 cells and induced permanent cell cycle arrest at the G1 phase. Long-term IL-32θ accumulation triggered permanent senescence and chromosomal instability in MDA-MB-231 cells. Genotoxic drug doxorubicin (DR) reduced the viability of MDA-MB-231 cells not expressing IL-32θ more than in cells expressing IL-32θ. Overall, these findings suggest that IL-32θ exerts antiproliferative effects in breast cancer cells and initiates senescence, which may cause DR resistance. Therefore, targeting IL-32θ in combination with DR treatment may not be suitable for treating metastatic breast cancer.

Jinju Kim, Hyo-Min Park, Chae-Min Lim, Kyeong-Bae Jeon, Seonhwa Kim, Jin Lee, Jin-Tae Hong, Deok-Kun Oh, Young Yang & Do-Young Yoon. BMB Reports -0001;0:. https://doi.org/10.5483/BMBRep.2024-0124

Exposure to particulate matter (PM) in the air harms human health. Most studies on particulate matter’s (PM) effects have primarily focused on respiratory and cardiovascular diseases. Recently, IL-32θ, one of the IL-32 isoforms, has been demonstrated to modulate cancer development and inflammatory responses. This study revealed that one-point mutated IL-32θ (A94V) plays an important role in attenuating skin inflammation. IL-32θ (A94V) inhibited PM-induced COX-2, a pro-inflammatory cytokine GM-CSF and CYP1A1 in PM-exposed human keratinocytes HaCaT cells. IL-32θ (A94V) modulating effects were mediated via down-regulating ERK/p38/NF-κB/ AP-1 and AhR/ARNT signaling pathways. Our study indicates that PM triggers skin inflammation by upregulating COX-2, GM-CSF and CYP1A1 expression. IL-32θ (A94V) suppresses the expressions of COX-2, GM-CSF, and CYP1A1 by blocking the nuclear translocation of NF-κB and AP-1, as well as inhibiting the activation of the AhR/ARNT signaling pathway. Our findings offer valuable insights into developing therapeutic strategies and potential drugs to mitigate PM-induced skin inflammation by inhibiting the ERK/p38/NF-κB/AP-1 and AhR/ARNT signaling pathways.